tag:theconversation.com,2011:/africa/topics/meteor-931/articlesMeteor – The Conversation2023-10-20T15:54:22Ztag:theconversation.com,2011:article/2159132023-10-20T15:54:22Z2023-10-20T15:54:22ZHow to watch October’s Orionids meteor shower and contemplate the wonders of the sky<figure><img src="https://images.theconversation.com/files/555005/original/file-20231020-17-bq3p8g.jpg?ixlib=rb-1.1.0&rect=11%2C0%2C3964%2C2377&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Orionids meteor shower takes place between October and November.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/2016-orionids-meteor-shower-1024802635">Brian Spencer / Shutterstock</a></span></figcaption></figure><p>Throughout the year, there are different meteor showers that all have different properties and can be more or less easy to spot. </p>
<p>During October, it’s <a href="https://www.rmg.co.uk/stories/topics/orionid-meteor-shower-2023-when-where-see-it-uk">time for the Orionids</a>, one of the best known meteor showers and also the most reliable. This is also an amazing opportunity to venture outside, observe them yourself and find out what makes them so special.</p>
<p>Shooting stars aren’t actually stars, but are caused by meteoroids. These are essentially rocks travelling in space. They can be similar in size to small pebbles and sand or, in rarer cases, bigger objects. </p>
<p>As our Earth moves through its orbit around the Sun, it can run into these objects by chance. There is a lot of this material hitting Earth: <a href="https://science.nasa.gov/solar-system/meteors-meteorites/facts/">approximately 48 tonnes per day</a>.</p>
<p>As the particles enter our atmosphere, they become meteors. The Orionids have an <a href="https://science.nasa.gov/solar-system/meteors-meteorites/orionids/">average speed of about 61 km/s</a>. The interaction with our atmosphere causes them to burn up at high altitude, cause bright streaks in the sky visible for a short time. </p>
<h2>Where are they from?</h2>
<p>Meteor showers, though, are not random encounters with meteoroids. Earth sometimes passes through denser regions of space debris left behind by comets as they travel around the Sun. </p>
<p>Comets are dirty snowballs made of loose material that is held together by frozen gases. When the Earth encounters comet debris, meteors can streak through the sky, putting on a spectacular display.</p>
<p>Each meteor shower is linked to a specific comet. The Orionids are of interest, not because there are lots of meteors, but because they are linked to Halley’s comet. This comet was <a href="https://science.nasa.gov/solar-system/comets/1p-halley/">the first to be recognised as periodic</a> – those with orbital periods around the Sun of less than 200 years. </p>
<p>Halley completes an orbit every 75 years. You might have missed it when it was close to us in 1986, but you can still see its trail through the Orionids.</p>
<p>When Halley gets close to the Sun, its ice turns to gas, leaving behind a trail of loose rubble. As Earth passes through this, we encounter the Orionids meteor shower.</p>
<p>Meteor showers are easy to enjoy as no specialist equipment is required. But we must practice patience and hope for good weather. Here ere are some tips to ensure your skywatching is successful.</p>
<h2>Timing</h2>
<p>Make sure to pick the right time. There are at least a <a href="https://www.rmg.co.uk/stories/topics/meteor-shower-guide">dozen meteor showers throughout the year</a> worth catching. They are named after constellations, indicating from which direction the meteors enter our atmosphere.</p>
<p>If you notice the streaks over a night, they will all seemingly radiate from one specific point in the sky (the radiant). For the Orionids that lies in the constellation of Orion, just towards the top left of its shoulder, which is marked by the star Betelgeuse. When you’ve decided on a date, the most promising time of night is usually the second half.</p>
<p>The Orionids start at the beginning of October and end at the beginning of November. On 21-22 October 2023, they reach a peak – when the highest meteor rates are expected. </p>
<p>For the Orionids, you can see an average of <a href="https://astronomynow.com/2022/10/19/watch-the-orionid-meteor-shower-peak-on-friday-night/">40-70 meteors per hour</a>. If you miss the peak, you will still be able to catch them, you just won’t see as many.</p>
<p>The Moon can make things tricky. A bright moonlit sky really does not help. So the best times are when the Moon is below the horizon or there’s a lunar phase that is not that bright. This year, the Moon is 37% illuminated during the Orionids peak, making conditions good but not ideal.</p>
<h2>Location</h2>
<p>Light is your enemy. Even if the Moon isn’t shining, you need to avoid bright lights. Find a spot that is not directly illuminated, but where you feel safe. </p>
<p>You can work with <a href="https://education.nationalgeographic.org/resource/light-pollution/">light pollution</a> in general if it is not too extensive. But the darker the sky is, the better the chances of seeing meteors. </p>
<p>Furthermore, a good view of the sky is required. That does not just mean looking towards the radiant, since meteors will streak across the entire sky. </p>
<p>Make sure you can see as much sky as possible. It might also be worth bringing a deck chair to lie back comfortably.</p>
<h2>Patience</h2>
<p>To fully appreciate the darkness of the sky and spot even the fainter meteors, you have to ensure your eyes are adjusted to dark conditions. This takes 20 to 30 minutes and cannot be rushed. </p>
<p>Stepping into your garden for a quick glimpse doesn’t work. You should wrap up warm and take something hot to drink with you to keep you going.</p>
<p>Remember that you can spoil your eyes’ adaptation to the dark by switching on a bright white light source. If you need light, cover your torch with a red filter. You will be surprised how much you can actually see at night by giving your eyes time to adapt.</p>
<p>The rates that are quoted for meteor showers (40-70 meteors per hour for the Orionids) are averages. They also refer to the darkest possible sky and assume the radiant is exactly above your head.</p>
<h2>Sky watching</h2>
<p>Meteor watching is an amazing activity for everyone and does not require specialised equipment. It engages you with the Universe and requires you to step out of your hectic routine, slow down and actually watch the night sky.</p>
<p>This act of calmness and awareness of your surroundings gives you the perfect environment to reflect upon your life and the universe, especially when thinking about how these meteors actually are parts of Halley’s comet and formed the building block of what we now call our solar system.</p>
<p>The Orionids are a unique opportunity to be inspired to skywatch and reconnect with the sky. So head out there and explore.</p><img src="https://counter.theconversation.com/content/215913/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Brown does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The meteor shower happens when Earth passes through debris from Halley’s comet.Daniel Brown, Lecturer in Astronomy, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2111842023-08-08T00:38:18Z2023-08-08T00:38:18ZA spectacular fireball just streaked across Melbourne – but astronomers didn’t see it coming<figure><img src="https://images.theconversation.com/files/541597/original/file-20230808-27645-48m1o0.jpg?ixlib=rb-1.1.0&rect=11%2C0%2C1985%2C1616&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://twitter.com/markjdavidson/status/1688662681467998211">Mark Davidson / Twitter</a></span></figcaption></figure><p>The first hours after a fireball sighting are like a detective mystery. Last night around midnight, people across Melbourne took to social media to report sightings of a bright light slowly streaking across the sky.</p>
<p>Video footage clearly shows the fireball break apart, with these fragments in turn burning up, meaning this object was big.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1688553695842349057"}"></div></p>
<h2>An unexpected piece of space junk</h2>
<p>There <a href="https://twitter.com/10NewsFirstMelb/status/1688671656284401664">have been reports</a> across Victoria of a loud explosion. Known as <a href="https://www.britannica.com/science/sonic-boom">sonic booms</a>, such sounds imply the pieces survived long enough to enter the lower atmosphere – otherwise they wouldn’t be audible from the ground. In turn, this tells us at least a part of this fireball was dense.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1688556188043206656"}"></div></p>
<p>Additionally, the glow of the fireball had clearly discernible colours, particularly orange, in some videos. This tells us the object isn’t a space rock, but is human-made, with a significant amount of plastics or metals burning up (familiar to anyone in high school chemistry class burning materials in the Bunsen burner).</p>
<p>So, it’s likely we just witnessed several tonnes of space junk – anything humans have put into orbit that isn’t under our control any longer – re-enter Earth’s atmosphere. However, nothing was predicted for reentry on the global space debris tracking site <a href="https://www.satview.org/">SatView</a>.</p>
<p>According to <a href="https://twitter.com/planet4589/status/1688701218086952962">an early analysis</a> by US-based astronomer Jonathan McDowell, the fireball may have been the third stage of a Soyuz 2 rocket <a href="https://everydayastronaut.com/glonass-k2-no-13-kosmos-2569-soyuz-2-1b-fregat/">carrying the navigation satellite GLONASS-K2</a>. This was launched by Roscosmos (the Russian space agency) on August 7 from the Plesetsk Cosmodrome about 800km north of Moscow. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1688701218086952962"}"></div></p>
<p>The incredible brightness of the fireball is thanks to the tremendous speed at which objects re-enter Earth’s thin upper atmosphere, 25,000 kilometres per hour or more. </p>
<p>When you rub your hands together, they get warm from the friction between them. Do that a thousand times faster and you can start to imagine them glowing white hot from the heat. If the friction is between the metal of the space junk and Earth’s thin atmosphere at an altitude of 100km, we can get a very bright glow. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/satellites-and-space-junk-may-make-dark-night-skies-brighter-hindering-astronomy-and-hiding-stars-from-our-view-202047">Satellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view</a>
</strong>
</em>
</p>
<hr>
<h2>You can help astronomers with the details</h2>
<p>To help us confirm what the fireball was and where it came from, we need witnesses to download the <a href="http://fireballsinthesky.com.au/download-app/">Fireballs in the Sky App</a> and recreate the passage of that trail as best they can.</p>
<p>From all those sightings we can triangulate the trajectory and determine where any surviving pieces might have landed and try to collect them. Reports so far are conflicting and we need more data. It appears it came into the atmosphere from the north-west across Victoria to Tasmania in the south-east, but it’s too soon to tell what its exact path was.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1688560558373851136"}"></div></p>
<p>Most space junk doesn’t make it to Earth. The incredible heat of 5,000 Kelvin or greater generated by the re-entry burns up almost all such pieces. </p>
<p>Some hardier engine blocks can make it to the ground, however, which is why alerts about space junk re-entering the atmosphere are sent out to aircraft in particular.</p>
<p>However, space junk travels so fast, even a very small mistake in the calculation of the re-entry will have it show up hundreds of kilometres away instead. For most purposes, such warnings are not as helpful as they could be.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/airplanes-face-a-growing-risk-of-being-hit-by-uncontrolled-re-entries-of-rockets-used-to-launch-satellites-202400">Airplanes face a growing risk of being hit by uncontrolled re-entries of rockets used to launch satellites</a>
</strong>
</em>
</p>
<hr>
<p>To improve this system, we need better tracking stations on the ground and advances in the modelling of the interaction between space junk and the upper atmosphere to improve our forecasts.</p>
<p>Thankfully buildings, let alone people, are <em>tiny</em> targets relative to the vast unpopulated reaches of land and sea. While there <a href="https://en.wikipedia.org/wiki/List_of_space_debris_fall_incidents">have been reported hits</a>, these are thankfully incredibly rare, making space junk hardly a danger for us on Earth. </p>
<p>As astronomers now rush to work out the details of this beautiful fireball, it also marks a spectacular opening for Australia’s <a href="https://www.scienceweek.net.au">National Science Week</a>, with thousands of live talks explaining science as widely as possible, just like this event.</p><img src="https://counter.theconversation.com/content/211184/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Duffy receives funding from the Australian Research Council and is employed at Swinburne University of Technology </span></em></p>A mysterious hunk of space junk buzzed through Australian skies last night. It may have been the third stage of a Soyuz 2 rocket just launched by Russia.Alan Duffy, Director of the Space Technology and Industry Institute, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2091012023-07-07T14:12:35Z2023-07-07T14:12:35ZPhysicist who found spherical meteor fragments claims they may come from an alien spaceship – here’s what to make of it<figure><img src="https://images.theconversation.com/files/536320/original/file-20230707-25-qnitc7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6586%2C2997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Anybody out there?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/view-space-galaxy-stars-universe-filled-1995429968">Triff/Shutterstock</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Avi Loeb, a physicist from Harvard University in the US, <a href="https://www.independent.co.uk/news/world/americas/avi-loeb-interstellar-object-aliens-b2369534.html">has recovered</a> 50 tiny spherical iron fragments from the bottom of the Pacific Ocean that he claims may be material from an interstellar alien spaceship. </p>
<p>Loeb is linking his finding with the passage of a fireball in January 2014. The meteor was observed by sensors of the US Department of Defense that track all objects entering the Earth’s atmosphere. It was recorded as travelling faster than most meteors and eventually broke up over the South Pacific Ocean near Papua New Guinea. </p>
<p>Data on the object is held by Nasa’s <a href="https://cneos.jpl.nasa.gov/">Centre for Near Earth Object Studies</a> (CNEOS). The meteor’s official name is CNEOS 20140108, and is also referred to as IM1 (for interstellar meteor).</p>
<figure class="align-center ">
<img alt="Loeb next to image of spherule" src="https://images.theconversation.com/files/536316/original/file-20230707-21-5ea08a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536316/original/file-20230707-21-5ea08a.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=307&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536316/original/file-20230707-21-5ea08a.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=307&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536316/original/file-20230707-21-5ea08a.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=307&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536316/original/file-20230707-21-5ea08a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=385&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536316/original/file-20230707-21-5ea08a.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=385&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536316/original/file-20230707-21-5ea08a.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=385&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Loeb next to image of spherule.</span>
<span class="attribution"><span class="source">NewsNation/Youtube</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>There is a very large scientific leap from observing a fireball to claiming it is an alien spaceship. What is the evidence on which Loeb bases the claim? And how likely is it to be true? </p>
<h2>‘Oumuamua, an interstellar comet</h2>
<p>We have already had at least one visitor from interstellar space - the comet <a href="https://theconversation.com/discovery-of-cigar-shaped-asteroid-from-outer-space-could-help-unveil-secrets-of-extrasolar-worlds-87873">'Oumuamua</a>. The appearance of 1I/2017U1, the official name for 'Oumuamua, was certainly an unusual event. The object was observed in 2017 as it was leaving the Solar System. Its <a href="https://legacy.ifa.hawaii.edu/info/press-releases/interstellar/interstellar_orbit.pdf">trajectory</a> is different from the near-circular orbits of the planets and elliptical orbits of comets.</p>
<p>The comet’s path was traced back, with scientists discovering that it had come from well beyond the outermost fringes of the Solar System. Scientists were excited but also intrigued - although its shape was not captured on camera, the way that light reflected from it as it rotated suggested that it had an odd shape like a cigar when viewed side-on or a plate when viewed from the top.</p>
<figure class="align-center ">
<img alt="'Oumuamua" src="https://images.theconversation.com/files/536103/original/file-20230706-23-ul92t8.jpeg?ixlib=rb-1.1.0&rect=42%2C22%2C1235%2C768&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536103/original/file-20230706-23-ul92t8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536103/original/file-20230706-23-ul92t8.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536103/original/file-20230706-23-ul92t8.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536103/original/file-20230706-23-ul92t8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536103/original/file-20230706-23-ul92t8.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536103/original/file-20230706-23-ul92t8.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">‘Oumuamua.</span>
<span class="attribution"><span class="source">ESO/M. Kornmesser</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>In a thoughtful <a href="https://blogs.scientificamerican.com/observations/how-to-search-for-dead-cosmic-civilizations/">article written in 2018</a>, Loeb speculated that 'Oumuamua might be artificial, rather than natural in origin – the product of an alien civilisation. He suggested that we should keep searching for interstellar debris in the Solar System. </p>
<p>In pursuit of such debris, Loeb’s team interrogated the CNEOS database, looking for objects with unusual orbital characteristics. That’s when they found CNEOS 20140108 and, based on its high velocity, suggested it was an <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ac8eac/pdf">interstellar meteor</a> – giving it the more manageable name of IM1. </p>
<p>Modelling the path of the fireball, Loeb identified a specific area of the South Pacific where he believed debris from IM1 would be deposited. Following a dredging operation in the area with a powerful magnet, he now claims to have found <a href="https://www.independent.co.uk/news/world/americas/avi-loeb-interstellar-object-aliens-b2369534.html">material from IM1</a>.</p>
<p>But what are the chances that he has found genuine interstellar debris at all, never mind a spaceship?</p>
<h2>Cosmic spherules?</h2>
<p>The metallic spherules that have been recovered are each about half a millimetre in diameter. It isn’t impossible for them to be of extraterrestrial origin: several previous expeditions have recovered spherules from space from the seabed.</p>
<p>The first expedition to find such samples was HMS Challenger in 1872-76. Material dredged from the ocean floor <a href="https://www.nhm.ac.uk/content/dam/nhmwww/discover/challenger/challenger-6-two-column.jpg.thumb.768.768.jpg">contained</a> many metallic droplets, described at the time, quite accurately, as “cosmic spherules”. Droplets from space are spherical because they solidify from molten material torn from the surface of meteorites as they traverse the atmosphere.</p>
<p>Subsequent expeditions throughout the 20th century have also found cosmic spherules at the bottom of the ocean, but it has become harder to identify them. This is because, in the 150 years since the Challenger expedition, the amount of pollution has increased on Earth. </p>
<p>In 1872, the industrial revolution was in its infancy in Europe and practically non-existent in the southern hemisphere. Hence pollution such as “fly ash” (waste from burning coal) and particles from vehicles was minimal. Many of these pollutants are also spherical in appearance and metallic in composition.</p>
<p>Today, products from industrial processes and vehicles are everywhere. So, without an actual analysis of the composition of the spherules and a comparison with analyses of meteorites (and common terrestrial pollutants), it is not possible to identify any as extraterrestrial.</p>
<h2>Interstellar?</h2>
<p>But Loeb doesn’t just think the material is from space, he thinks it is from interstellar space – arguing <a href="https://www.dailymail.co.uk/sciencetech/article-12243125/Harvards-Avi-Loeb-says-50-microscopic-spherules-recovered-Pacific-alien-probe.html">“this could be the first time humans put their hands on interstellar material”</a>. </p>
<p>This is simply not true. We have an abundance of interstellar material on Earth. Some of it is almost certainly on the ocean floor, but not in the form collected by Loeb. </p>
<p>The interstellar material to which I am referring comes in several different varieties. It is well known by astronomers that the interstellar medium - the space between stars - is not empty, but contains several different molecules, many of which are organic (made up of chains or rings of carbon). A portion of these molecules got mixed into the region of space where the Solar System was starting to form. </p>
<p>Stars themselves have also contributed material to the interstellar medium, as they evolved or exploded as supernovas. Some of this material comes as tiny diamonds or sapphires - rare mementoes of stars that lived and died before the Sun was born. These grains became part of the dust cloud that collapsed to form the Solar System, and were eventually carried to Earth in meteorites.</p>
<h2>Alien spacecraft?</h2>
<p>Loeb’s evidence for an extraterrestrial source for the material – never mind an interstellar origin – is rather shaky. He has found metallic spherules. For me (and many others) to accept that these spherules are extraterrestrial, I’d need firm analytical evidence. What is their composition? What is their age? Can we rule out terrestrial pollutants? Can we rule out debris from extraterrestrial material from within the Solar System? </p>
<p>The first question, about composition, has been answered: analysis of the spherules shows them to be <a href="https://www.dailymail.co.uk/sciencetech/article-12259813/EXCL-Harvard-scientists-say-UFO-crashed-ocean-2014-appears-artificial-origin.html">mainly iron with a few trace metals</a>.</p>
<p>We know meteors from our Solar System contain iron and nickel, echoing the relative abundances of these metals in the Sun. But the spherules apparently contain “negligible” amounts of nickel - thus indicating that they are almost certainly not from meteors within the Solar System. This does not, however, prove they are interstellar - it merely makes it more likely that they’re terrestrial pollutants.</p>
<p>The most convincing evidence would be to measure an age for the spherules greater than that of the Sun - which would identify them as interstellar.</p>
<p>And that would be amazing, but it would not necessarily identify them as having an artificial, rather than natural origin. I am not sure what evidence would be sufficiently convincing for this - maybe the autograph of the alien engineer who built the spacecraft?</p><img src="https://counter.theconversation.com/content/209101/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Grady receives funding from the STFC and the UK Space Agency. She is Professor of Planetary and Space Sciences at the Open University, Chancellor of Liverpool Hope University and Senior Researcher at the Natural History Museum. She tweets as @MonicaGrady</span></em></p>There is a very large scientific leap from observing a fireball to claiming it as an alien spaceship.Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1878362022-08-01T20:03:39Z2022-08-01T20:03:39ZMeteors seem to be raining down on New Zealand, but why are some bright green?<figure><img src="https://images.theconversation.com/files/476788/original/file-20220731-19335-76trxr.jpg?ixlib=rb-1.1.0&rect=5%2C304%2C3828%2C1851&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Greg Price</span>, <span class="license">Author provided</span></span></figcaption></figure><p>New Zealand may seem to be under meteor bombardment at the moment. After a <a href="https://theconversation.com/equivalent-to-1-800-tonnes-of-tnt-what-we-now-know-about-the-meteor-that-lit-up-the-daytime-sky-above-new-zealand-186636">huge meteor exploded</a> above the sea near Wellington on July 7, creating a sonic boom that could be heard across the bottom of the South Island, a smaller fireball was captured two weeks later above Canterbury. </p>
<p><a href="https://fireballs.nz/">Fireballs Aotearoa</a>, a collaboration between astronomers and citizen scientists which aims to recover freshly fallen meteorites, has received a lot of questions about these events. One of the most frequent is about the bright green colour, and whether it is the same green produced by auroras. </p>
<figure class="align-center ">
<img alt="An image of an aurora australis" src="https://images.theconversation.com/files/476789/original/file-20220731-20-zrewrz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/476789/original/file-20220731-20-zrewrz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/476789/original/file-20220731-20-zrewrz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/476789/original/file-20220731-20-zrewrz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/476789/original/file-20220731-20-zrewrz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/476789/original/file-20220731-20-zrewrz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/476789/original/file-20220731-20-zrewrz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An aurora australis observed from the international space station.</span>
<span class="attribution"><span class="source">Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Green fireballs have been reported and filmed in New Zealand regularly. Bright meteors often signal the arrival of a chunk of asteroid, which can be anywhere between a few centimetres to a metre in diameter when it comes crashing through the atmosphere. </p>
<p>Some of these asteroids contain nickel and iron and they hit the atmosphere at speeds of up to 60km per second. This releases an enormous amount of heat very quickly, and the vapourised iron and nickel radiate green light. </p>
<p>But is this the same as the bright green of an aurora? For the most recent meteor, the answer is mainly no, but it’s actually not that simple.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/equivalent-to-1-800-tonnes-of-tnt-what-we-now-know-about-the-meteor-that-lit-up-the-daytime-sky-above-new-zealand-186636">Equivalent to 1,800 tonnes of TNT: what we now know about the meteor that lit up the daytime sky above New Zealand</a>
</strong>
</em>
</p>
<hr>
<h2>The colours of a meteor trail</h2>
<p>The green glow of the aurora is caused by oxygen ions in the upper atmosphere, created by collisions between atmospheric oxygen molecules and particles ejected by the sun. </p>
<p>These oxygen ions recombine with electrons to produce oxygen atoms, but the electrons can persist in an excited state for several seconds. In an energy transition known as “forbidden” because it does not obey the usual quantum rules, they then radiate the auroral green light at 557nm wavelength.</p>
<p>A meteor can also shine by this route, but only if it’s extremely fast. Very fast meteors heat up in the thin atmosphere above 100km where auroras form. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/are-the-northern-lights-caused-by-particles-from-the-sun-not-exactly-174019">Are the northern lights caused by 'particles from the Sun'? Not exactly</a>
</strong>
</em>
</p>
<hr>
<p>If you want to see a green auroral wake from a meteor, watch out for the Perseid meteor shower, which has now started and will peak on August 13 in the southern hemisphere. </p>
<p>Also arriving at about 60km per second, the Perseids are extremely fast bits of the <a href="https://www.space.com/33677-comet-swift-tuttle-perseid-meteor-shower-source.html">comet Swift-Tuttle</a>. Some Perseids trail a beautiful, glowing and distinctly green wake behind them, particularly at the start of their path.</p>
<p>Once the Canterbury meteor hit on July 22, the capricious winds of the upper atmosphere twisted the gently glowing trail, resulting in a pale yellow glow towards the end (as seen in the GIF below, also recorded by Greg Price for an earlier meteor). This is caused by sodium atoms being continually excited in a catalytic reaction involving ozone.</p>
<p><img src="https://cdn.theconversation.com/static_files/files/2231/The_22_July_meteor_-_persistent_train_-_credit_Greg_Price.gif?1659310010" width="100%"> </p>
<h2>Are we being bombarded by meteors?</h2>
<p>Yes and no. The arrival of big, booming green meteors and the dropping of meteorites isn’t rare in New Zealand, but it is rare to recover the rock. Fireballs Aotearoa is working to improve the recovery rate.</p>
<p>In an average year, perhaps four meteorites hit New Zealand. We’re encouraging citizen scientists to build their own meteor camera systems so they can catch these events. </p>
<p>By comparing the meteor against the starry background and triangulating images caught by multiple cameras, we can pin down the meteor’s position in the atmosphere to within tens of metres.</p>
<figure class="align-center ">
<img alt="The July 22 meteor as seen by a specialised meteor camera near Ashburton." src="https://images.theconversation.com/files/476790/original/file-20220731-43929-h2dp31.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/476790/original/file-20220731-43929-h2dp31.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/476790/original/file-20220731-43929-h2dp31.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/476790/original/file-20220731-43929-h2dp31.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/476790/original/file-20220731-43929-h2dp31.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/476790/original/file-20220731-43929-h2dp31.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/476790/original/file-20220731-43929-h2dp31.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The July 22 meteor as seen by a specialised meteor camera near Ashburton.</span>
<span class="attribution"><span class="source">Campbell Duncan/NASA/CAMS NZ</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Not only does that help us find the rock, but it tells us what the pre-impact orbit of the meteoroid was, which in turn tells us which part of the solar system it came from. This is a rather efficient way of sampling the solar system without ever having to launch a space mission.</p>
<figure class="align-center ">
<img alt="Map of witness reports and cameras." src="https://images.theconversation.com/files/476791/original/file-20220731-31484-7i4x0t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/476791/original/file-20220731-31484-7i4x0t.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/476791/original/file-20220731-31484-7i4x0t.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/476791/original/file-20220731-31484-7i4x0t.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/476791/original/file-20220731-31484-7i4x0t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/476791/original/file-20220731-31484-7i4x0t.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/476791/original/file-20220731-31484-7i4x0t.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Witness reports and high-resolution meteor cameras help to calculate a meteor’s trajectory. This map shows the approximate trajectory of the July 22 meteor at the top of the red shape in the centre.</span>
<span class="attribution"><span class="source">Fireballs Aotearoa and International Meteor Association</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Fireballs Aotearoa is rapidly populating Otago with meteor cameras and there are half a dozen more in other parts of the South Island. The North Island isn’t well covered yet, and we’re keen for more people (in either island) to build or buy a meteor camera and keep it pointed at the sky. </p>
<p>Then next time a bright meteor explodes with a boom above New Zealand, we may be able to pick up the meteorite and do some good science with it.</p>
<hr>
<p><em>Many thanks for the input from Jim Rowe of the UK Fireball Alliance, and Greg Price who photographed the July 22 meteor and the persistent train.</em></p><img src="https://counter.theconversation.com/content/187836/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>William Jack Baggaley receives funding from University of Canterbury. </span></em></p>The green glow of an aurora is caused by oxygen ions in the upper atmosphere. Some meteors can glow in this way, too, but only if they are extremely fast.Jack Baggaley, Professor Emeritus Physics and Astronomy, University of CanterburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1866362022-07-11T04:25:07Z2022-07-11T04:25:07ZEquivalent to 1,800 tonnes of TNT: what we now know about the meteor that lit up the daytime sky above New Zealand<figure><img src="https://images.theconversation.com/files/473267/original/file-20220710-45032-fwekrn.jpg?ixlib=rb-1.1.0&rect=0%2C5%2C1280%2C703&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This image shows meteors that skimmed the atmosphere during just one night in March this year.</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>Meteorites hit New Zealand three or four times a year, but the fireball that shot across the sky above Cook Strait last week was unusual.</p>
<p>It had the explosive power of 1,800 tonnes of TNT and was captured from space by US satellites. It set off a sonic boom heard throughout the southern parts of the North Island. </p>
<p>Witnesses described a “giant bright orange fireball” and a flash that left a “trail of smoke that hung around for a few minutes”. </p>
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<p>The fireball was most likely caused by a small meteor, up to a few metres in diameter, traversing Earth’s atmosphere. It was one of only five impacts of greater than a thousand tonnes of energy globally in the past year. Most meteors are tiny, creating “shooting stars” that only briefly skim the atmosphere. </p>
<p>The fragmentation of the meteor produced a shock wave strong enough to be picked up by <a href="https://www.geonet.org.nz/">GeoNet</a>, a network of earthquake seismometers, with a flash bright enough to be recorded by a global lightning-tracking satellite. The Metservice’s Wellington radar picked up the leftover smoke trail south of the tip of the North Island. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1544899975380758528"}"></div></p>
<p>But what is the chance of finding any of the its fragments, or meteorites, that dropped to Earth? </p>
<p>As part of <a href="https://fireballs.nz/">Fireballs Aotearoa</a>, a recently established collaboration between the universities of Otago and Canterbury and the astronomy community to track down freshly fallen meteorites, we are deploying specialised night-sky meteor cameras across New Zealand. </p>
<p>Fireballs Aotearoa’s meteor cameras only operate at night, but the compiled witness reports reveal the July 7 fireball travelled from northwest to southeast and most likely fragmented over the ocean. Unfortunately, any meteorites are therefore probably inaccessible.</p>
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<h2>Meteorites on Earth</h2>
<p>Earth mainly gets meteorites from the asteroid belt, the Moon and Mars. They range from those only visible with a microscope to gigantic ones, such as the roughly 10km-wide meteorite that triggered the extinction of dinosaurs 65 million years ago. </p>
<p>Meteorites are scientific goldmines. Some contain material from before the Sun formed. Others tell us about the history of the young Sun’s planet-forming disk, when dust circulating around it began to clump into larger rocks and, eventually, planets. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/as-the-perseverance-rover-lands-on-mars-theres-a-lot-we-already-know-about-the-red-planet-from-meteorites-found-on-earth-155459">As the Perseverance rover lands on Mars, there's a lot we already know about the red planet from meteorites found on Earth</a>
</strong>
</em>
</p>
<hr>
<p>Lunar meteorites show the Moon originated from the collision of a small planet with Earth. Martian meteorites tell us about the surface and interior of our closest planet. We don’t even need to send a spaceship.</p>
<p>If a meteor is recorded by several night-sky cameras, then its trajectory can be calculated and any resulting meteorites potentially located. The trajectory also tells us the meteor’s pre-impact orbit, allowing us to estimate where in the Solar System it originated. </p>
<h2>How to help find a meteorite</h2>
<p>New Zealand has nine known meteorites. Although the fireball wasn’t seen, the most recent was the <a href="https://www.nzherald.co.nz/nz/meteorite-crashes-through-roof-of-auckland-house/BFUVILM6HJMFDCEG7YWXD4CCRA/">Auckland meteorite</a> that crashed through an Ellerslie roof in 2003. Our <a href="https://www.lpi.usra.edu/meteor/metbull.php?nwas=&strewn=&code=73471">analysis</a> shows this rock belongs to the ordinary chondrite group and therefore was part of a small asteroid only slightly younger than the Sun. </p>
<p>Last year, the British citizen-led <a href="https://www.ukfall.org.uk/">fireball network UKFall</a> captured footage of an enormous fireball over southern England. The <a href="https://www.europlanet-society.org/the-fall-of-the-winchcombe-meteorite/">debris was located on a driveway</a> in Winchcombe, Gloucestershire – where the owner initially assumed someone had emptied their barbecue. </p>
<p>Now on display in the Natural History Museum in London, the Winchcombe meteorite turned out to be a type incredibly <a href="https://www.bbc.com/news/science-environment-57763422">rare on Earth</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1498225844136955912"}"></div></p>
<p>It is similar to the 5g of material returned in 2020 from <a href="https://www.nature.com/articles/s41550-021-01551-5">asteroid Ryugu by the Hayabusa 2 spacecraft</a>, except the meteorite gave scientists a hundred times as much to work with. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-are-asteroids-made-of-a-sample-returned-to-earth-reveals-the-solar-systems-building-blocks-176548">What are asteroids made of? A sample returned to Earth reveals the Solar System's building blocks</a>
</strong>
</em>
</p>
<hr>
<p>Although the Wellington fireball on July 7 probably didn’t drop a meteorite on land, the next one might. And you can join the meteorite hunt by reporting any sightings to <a href="https://fireballs.nz/">Fireballs Aotearoa</a>.</p>
<hr>
<p><em>We would like to acknowledge Jim Rowe and Jeremy Taylor, our colleagues at Fireballs Aotearoa, for help with compiling this article.</em></p><img src="https://counter.theconversation.com/content/186636/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Scott receives funding from the MBIE Participatory Science Platform to build and deploy nightsky cameras across Otago.</span></em></p><p class="fine-print"><em><span>Michele Bannister receives funding from the Royal Society of New Zealand Te Apārangi to explore small worlds throughout the Solar System.</span></em></p>When the meteor exploded into pieces above New Zealand, it produced a shock wave strong enough to be picked up by earthquake seismometers. But any fragments have likely dropped into the ocean.James Scott, Associate Professor in Geology, University of OtagoMichele Bannister, Lecturer in Astronomy, School of Physical and Chemical Sciences Te Kura Matū, University of CanterburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1824342022-05-26T03:20:34Z2022-05-26T03:20:34ZFragments of a dying comet might put on a spectacular show next week – or pass by without a trace<figure><img src="https://images.theconversation.com/files/465169/original/file-20220524-21-u21zj2.jpg?ixlib=rb-1.1.0&rect=0%2C18%2C1398%2C2007&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The 1833 Leonid Meteor storm, as seen over Niagara Falls.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Leonid_Meteor_Storm_1833.jpg">Edmund Weiß (1888)</a></span></figcaption></figure><p>As Earth orbits the Sun, it ploughs through dust and debris left behind by comets and asteroids. That debris <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">gives birth to meteor showers</a> – which can be one of nature’s most amazing spectacles.</p>
<p>Most meteor showers are predictable, recurring annually when the Earth traverses a particular trail of debris. </p>
<p>Occasionally, however, Earth runs through a particularly narrow, dense clump of debris. This results in a meteor storm, sending <a href="https://blogs.loc.gov/headlinesandheroes/2020/09/how-newspapers-helped-crowdsource-a-scientific-discovery-the-1833-leonid-meteor-storm/#:%7E:text=The%20Leonid%20meteor%20storm%20was,know%20more%20about%20this%20phenomenon.">thousands of shooting stars streaking across the sky each hour</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Artist's impression of the great Leonid meteor storm of 1833" src="https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=919&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=919&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=919&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1154&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1154&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1154&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Artist’s impression of the 1833 Leonid meteor storm.</span>
<span class="attribution"><span class="source">Adolf Vollmy (April 1888)</span></span>
</figcaption>
</figure>
<p>A minor shower called the Tau Herculids could create a meteor storm for observers in the Americas next week. But while some websites promise “the most powerful meteor storm in generations”, astronomers are a little more cautious.</p>
<h2>Introducing comet SW3</h2>
<p>The story begins with a comet called <a href="https://cometography.com/pcomets/073p.html">73P/Schwassmann-Wachmann 3</a> (comet SW3 for short). First spotted in 1930, it is responsible for a weak meteor shower called the Tau Herculids, which nowadays appears to radiate from a point about ten degrees from the bright star Arcturus. </p>
<p>In 1995, comet SW3 <a href="https://cometography.com/pcomets/073p.html">suddenly and unexpectedly brightened</a>. A number of outbursts were observed over a few months. The comet had <a href="https://ui.adsabs.harvard.edu/abs/1996A%26A...310L..17C/abstract">catastrophically fragmented</a>, releasing huge amounts of dust, gas, and debris. </p>
<p>By 2006 (two orbits later), comet SW3 had disintegrated further, into <a href="https://www.nasa.gov/mission_pages/hubble/Comet_73P.html">several bright fragments accompanied by many smaller chunks</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Animated images of comet 73P as seen by the Hubble Space Telescope" src="https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=576&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=576&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=576&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=723&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=723&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=723&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fragments of comet 73P seen by the Hubble Space Telescope in 2006.</span>
<span class="attribution"><span class="source">NASA, ESA, H. Weaver (APL/JHU), M. Mutchler and Z. Levay (STScI)</span></span>
</figcaption>
</figure>
<h2>Is Earth on a collision course?</h2>
<p>This year, Earth will cross comet SW3’s orbit at the end of May.</p>
<p>Detailed computer modelling suggests debris has been spreading out along the comet’s orbit like enormous thin tentacles in space. </p>
<p>Has the debris spread far enough to encounter Earth? It depends on how much debris was ejected in 1995 and how rapidly that debris was flung outwards as the comet fell apart. But the pieces of dust and debris are so small we can’t see them until we run into them. So how can we get an insight into what might happen next week?</p>
<h2>Could history repeat itself?</h2>
<p>Our current understanding of meteor showers began 150 years ago with an event quite similar to SW3’s story.</p>
<p>A comet called <a href="https://www.nature.com/articles/061078c0">comet 3D/Biela</a> was discovered in 1772. It was a short-period comet, like SW3, returning every 6.6 years. </p>
<p>In 1846, the comet began to behave strangely. Observers saw its head had split in two, and some described an “archway of cometary matter” between the pieces.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Sketch of a comet split into two pieces, each with its own tail." src="https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=283&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=283&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=283&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=356&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=356&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=356&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sketch of comet 3D/Biela in February 1846, after it split into (at least) two pieces.</span>
<span class="attribution"><span class="source">Edmund Weiß</span></span>
</figcaption>
</figure>
<p>At the comet’s next return, in 1852, the two fragments had clearly separated and both were fluctuating unpredictably in brightness.</p>
<p>The comet was never seen again. </p>
<p>But in late November of 1872, an unexpected meteor storm graced northern skies, stunning observers with rates of more than 3,000 meteors per hour. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A paiting showing meteors raining down over mountains" src="https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=453&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=453&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=453&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=569&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=569&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=569&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The meteor storm of 1872.</span>
<span class="attribution"><span class="source">Amedee Guillemin</span></span>
</figcaption>
</figure>
<p>The meteor storm occurred when the Earth crossed 3D/Biela’s orbit: it was where the comet itself should have been two months earlier. A second storm, weaker than the first, occurred in 1885, when the Earth once more encountered the comet’s remains. </p>
<p>3D/Biela had disintegrated into rubble, but the two great meteor storms it produced served as a fitting wake. </p>
<p>A dying comet, falling apart before our eyes, and an associated meteor shower, usually barely imperceptible against the background noise. Are we about to see history repeat itself with comet SW3?</p>
<h2>What does this suggest for the Tau Herculids?</h2>
<p>The main difference between the events of 1872 and this year’s Tau Herculids comes down to the timing of Earth’s crossing of the cometary orbits. In 1872, Earth crossed Biela’s orbit several months <em>after</em> the comet was due, running through material lagging behind where the comet would have been.</p>
<p>By contrast, the encounter between Earth and SW3’s debris stream next week happens several months <em>before</em> the comet is due to reach the crossing point. So the debris needs to have spread <em>ahead</em> of the comet for a meteor storm to occur.</p>
<p>Could the debris have spread far enough to encounter Earth? Some models suggest we’ll see a strong display from the shower, others suggest the debris will fall just short.</p>
<h2>Don’t count your meteors before they’ve flashed!</h2>
<p>Whatever happens, observations of next week’s shower will greatly improve our understanding of how comet fragmentation events happen.</p>
<p>Calculations show Earth will <a href="https://www.imo.net/files/meteor-shower/cal2022.pdf">cross SW3’s orbit at about 3pm, May 31 (AEST)</a>. If the debris reaches far enough forward for Earth to encounter it, then an outburst from the Tau Herculids is likely, but it will only last an hour or two. </p>
<p>From Australia, the show (if there is one) will be over before it’s dark enough to see what’s happening. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="View of the night sky showing the Tau Herculids radiant" src="https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=322&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=322&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=322&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=405&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=405&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=405&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For observers across Australia, the Tau Herculids radiant is low in the northern sky around 7pm local time.</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>Observers in north and south America will, however, have a ringside seat. </p>
<p>They are more likely to see a moderate display of slow-moving meteors than a huge storm. This would be a great result, but might be a little disappointing.</p>
<p>However, there is a chance the shower could put on a truly spectacular display. Astronomers are travelling across the world, just in case. </p>
<h2>What about Australian observers?</h2>
<p>There’s also a small chance any activity will last longer than expected, or even arrive a bit late. Even if you’re in Australia, it’s worth looking up on the evening of May 31, just in case you can get a glimpse of a fragment from a dying comet!</p>
<p>The 1995 debris stream is just one of many laid down by the comet in past decades. </p>
<p>During the early morning of May 31, around 4am (AEST), Earth will cross debris from the comet’s 1892 passage around the Sun. Later that evening, around 8pm, May 31 (AEST), Earth will cross debris laid down by the comet in 1897.</p>
<p>However, debris from those visits will have spread out over time, and therefore we expect only a few meteors to grace our skies from those streams. But, as always, we might be wrong - the only way to know is to go out and see! </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The night sky at midnight, showing the Tau Herculids radiant." src="https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=322&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=322&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=322&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=405&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=405&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=405&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">By midnight (local time), the Tau Herculids radiant will have moved to the north-western sky, seen from across Australia.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/182434/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Could the Tau Herculid meteor shower put on a spectacular show next week? Only time will tell.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandTanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1817272022-05-03T20:08:08Z2022-05-03T20:08:08ZThe Eta Aquariid meteor shower is set to light up the skies. Here’s how to get the best seat in the house<p>There’s something wonderful about sitting under the night sky, watching a meteor shower play out overhead. However, observers in the southern hemisphere usually get the short end of the stick, with <a href="https://spaceaustralia.com/news/ultimate-sky-guide-catching-meteors-your-backyard-2022">most of the best showers</a> strongly favouring those north of the equator. </p>
<p>Every May, however, southern observers get a special treat – the Eta Aquariid meteor shower. This year conditions promise to be perfect, making it the ideal opportunity for some autumnal meteor observation.</p>
<p>The forecast peak for this year’s Eta Aquariids falls on the morning of Saturday, May 7. The Moon is well out of the way, so meteors won’t be lost in its glare. </p>
<p>But what if skies are cloudy? Well, if you miss the morning of the peak, don’t panic! The Eta Aquariids are famed for their broad peak, and meteor rates typically stay high for about a week around the peak (May 4–11). So if Saturday morning is cloudy, try looking again on Sunday, or even Monday.</p>
<p>To get the best view, you’ll want to get up in the early hours of the morning and be well away from any bright city lights. Give your eyes time to adjust to the darkness. Take a chair or recliner to get comfortable, relax and gaze skywards. </p>
<p>You won’t even need a telescope! To best observe meteor showers, you’ll want to watch as wide an area of sky as possible. Using a telescope or binoculars would make the spectacle almost impossible to observe.</p>
<h2>Dust and debris from a famous comet</h2>
<p>As the Earth orbits the Sun, it continually runs into dust and debris from comets and asteroids. Every April and May, the Earth spends about six weeks traversing a river of dust left behind by the famous <a href="https://en.wikipedia.org/wiki/Halley%27s_Comet">Comet 1P/Halley</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/460275/original/file-20220428-18-qu16zo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Comet Halley, as seen in 1986. The head of the comet is to the left, with the blue gas tail pointing to the lower right, and the dust tail curving slightly towards the upper right." src="https://images.theconversation.com/files/460275/original/file-20220428-18-qu16zo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/460275/original/file-20220428-18-qu16zo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=417&fit=crop&dpr=1 600w, https://images.theconversation.com/files/460275/original/file-20220428-18-qu16zo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=417&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/460275/original/file-20220428-18-qu16zo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=417&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/460275/original/file-20220428-18-qu16zo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=524&fit=crop&dpr=1 754w, https://images.theconversation.com/files/460275/original/file-20220428-18-qu16zo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=524&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/460275/original/file-20220428-18-qu16zo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=524&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Comet 1P/Halley was photographed on March 8, 1986, during its last pass around the Sun.</span>
<span class="attribution"><span class="source">NASA/W. Liller</span></span>
</figcaption>
</figure>
<p>Every 76 years or so, Comet Halley swings close to the Sun. Its icy surface heats up until the ices boil off into space in a process called “<a href="https://astronomy.swin.edu.au/cosmos/s/sublimation">sublimation</a>”. This shrouds the comet in a gaseous coma, which is blown away from the Sun to generate the comet’s tail. </p>
<p>The gas escaping Halley’s surface carries dust grains, which gradually spread around the comet’s orbit. Some move ahead of the comet, while others lag behind. </p>
<p>Over thousands of years, the space around Halley’s orbit has become thick with dust grains. The comet is essentially moving through a dirty snowstorm of its own making! And each year, the Earth runs through that broad river of dust – giving birth to the Eta Aquariid meteor shower. </p>
<p>Interestingly, the Earth runs into Halley’s debris again in October, producing the famous <a href="https://theconversation.com/see-one-of-the-years-best-meteor-showers-thanks-to-halleys-comet-33091">Orionid meteor shower</a>. But we get a better show in May each year with the Eta Aquariids, as this is when we move closer to the centre of the dust stream.</p>
<hr>
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Read more:
<a href="https://theconversation.com/thousands-of-satellites-are-polluting-australian-skies-and-threatening-ancient-indigenous-astronomy-practices-173840">Thousands of satellites are polluting Australian skies, and threatening ancient Indigenous astronomy practices</a>
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</em>
</p>
<hr>
<h2>Where should I look?</h2>
<p>When dust left behind by a comet smashes into Earth’s atmosphere, it becomes a spectacular fiery streak of light high in the sky. This <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">usually happens about 80km above the ground</a>, although the largest bits of debris can penetrate pretty deep into the atmosphere before burning up entirely.</p>
<p>The dust grains in a meteor shower all move around the Sun at essentially the same speed and in the same direction. This means the grains are also travelling in the same direction as they hit the Earth. </p>
<p>But as they move towards an observer on the ground, that observer’s perspective will make their paths diverge, and they will seem to be radiating out from a single point in the sky. That point is known as a shower’s “radiant”. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/460306/original/file-20220428-9919-42jk0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Meteors from the Orionid meteor shower in 2011, radiating from a point near the lower left of the image." src="https://images.theconversation.com/files/460306/original/file-20220428-9919-42jk0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/460306/original/file-20220428-9919-42jk0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=455&fit=crop&dpr=1 600w, https://images.theconversation.com/files/460306/original/file-20220428-9919-42jk0m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=455&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/460306/original/file-20220428-9919-42jk0m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=455&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/460306/original/file-20220428-9919-42jk0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=571&fit=crop&dpr=1 754w, https://images.theconversation.com/files/460306/original/file-20220428-9919-42jk0m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=571&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/460306/original/file-20220428-9919-42jk0m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=571&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Orionid meteors are a great example of how meteors in a shower seem to radiate from a single point in the sky.</span>
<span class="attribution"><span class="source">Phil Hart</span></span>
</figcaption>
</figure>
<p>Meteors showers are named for the constellation in which their radiant lies. So the Eta Aquariids have a radiant near the star Eta Aquarii – <a href="https://theskylive.com/sky/constellations/aquarius-bright-stars">the tenth-brightest star in Aquarius</a>.</p>
<p>To see the Eta Aquariids, you’ll need to wait until the radiant rises – before that, the body of the Earth gets in the way. We’re lucky here in the southern hemisphere, as the Eta Aquariid radiant rises in the east at around 1:30 to 2am, local time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/460462/original/file-20220429-25229-42jk0m.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/460462/original/file-20220429-25229-42jk0m.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/460462/original/file-20220429-25229-42jk0m.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/460462/original/file-20220429-25229-42jk0m.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/460462/original/file-20220429-25229-42jk0m.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/460462/original/file-20220429-25229-42jk0m.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/460462/original/file-20220429-25229-42jk0m.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/460462/original/file-20220429-25229-42jk0m.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Eta Aquariids radiant will rise between 1.20am and 2.20am for cities across Australia.</span>
<span class="attribution"><span class="source">Museums Victoria</span></span>
</figcaption>
</figure>
<p>While the Eta Aquariid meteors can be seen anywhere in the sky, the ideal place to see the best number of meteors is about 45 degrees to the left or right of the radiant itself.</p>
<p>Fortunately, this year we have another spectacular sight in the morning sky. Four planets – Saturn, Mars, Jupiter and Venus – will all be in a line. To see the best meteor show, look about 45 degrees to the left or right of this line of planets.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/460467/original/file-20220429-25839-7wz786.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="view of the night sky showing the Eta Aquariid radiant above the eastern horizon, along with the planets in a line - Saturn (highest), then Mars, Jupiter and Venus." src="https://images.theconversation.com/files/460467/original/file-20220429-25839-7wz786.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/460467/original/file-20220429-25839-7wz786.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/460467/original/file-20220429-25839-7wz786.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/460467/original/file-20220429-25839-7wz786.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/460467/original/file-20220429-25839-7wz786.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/460467/original/file-20220429-25839-7wz786.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/460467/original/file-20220429-25839-7wz786.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The line of planets and the Eta Aquariid radiant as they will appear at around 4am on May 7 from Sydney (rising in the east). The sky will look mostly the same from Brisbane, Canberra and Perth at 4am (local time), Melbourne, Hobart and Adelaide at 4:30am (local time) and Darwin at 5am (local time).</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>To see how the planets and radiant will rise from your location, visit the Stellarium planetarium <a href="https://stellarium-web.org/">website</a>, set your location and move the date and time forward to the morning of May 7. If you turn on the “constellations” and “constellations art” (at the bottom of the screen), you can watch Aquarius and the planets rising from the comfort of your computer.</p>
<h2>How many meteors should I expect to see?</h2>
<p>The Eta Aquariids are the second best shower of the year for people in Australia. They can put on a spectacular show - but don’t expect to see meteors falling like snowflakes. </p>
<p>When the radiant first rises above the horizon, at around 1.30am, meteors from the shower will be few and far between. If you see five or six Eta Aquariids in that first hour, you should probably count yourself lucky.</p>
<p>That said, these early meteors could be really spectacular. Known as “Earth grazers”, they often seem to streak from near one horizon all the way across the sky. Earth grazers are the result of meteors hitting our atmosphere at a very shallow angle, almost edge on. They’re rare, but incredible to witness!</p>
<p>As the night goes on, and the radiant climbs higher into the sky, the number of meteors should increase. In the hour before dawn, you could easily see 20 to 30 meteors per hour. </p>
<p>Oh, and a word of warning: meteors are like buses – if you’re expecting 30 per hour, you can easily wait ten minutes and see nothing, before three come along at once. Make sure you dress warm so you can stay under the stars for at least half an hour, if not more! </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hunting-galaxies-far-far-away-heres-how-anyone-can-explore-the-universe-172233">Hunting galaxies far far away – here's how anyone can explore the universe</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/181727/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Each year, the Earth runs through a broad river of dust surrounding Comet Halley – giving birth to the spectacular Eta Aquariid meteor shower.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandTanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1770232022-03-01T13:37:02Z2022-03-01T13:37:02ZAn asteroid impact could wipe out an entire city – a space security expert explains NASA’s plans to prevent a potential catastrophe<figure><img src="https://images.theconversation.com/files/447109/original/file-20220217-25-11g19ha.jpg?ixlib=rb-1.1.0&rect=0%2C158%2C5097%2C3275&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A giant asteroid struck Earth and wiped out the dinosaurs 65 million years ago. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/chicxulub-asteroid-impact-royalty-free-illustration/713781277?adppopup=true">Mark Garlick/Science Photo Library via Getty Images</a></span></figcaption></figure><p>The Earth exists in a dangerous environment. Cosmic bodies, like asteroids and comets, are constantly zooming through space and often crash into our planet. Most of these are too small to pose a threat, but some can be <a href="https://www.nytimes.com/2007/03/16/opinion/16iht-edschweick.4929643.html">cause for concern</a>.</p>
<p>As a scholar who <a href="https://svetlabenitzhak.com/2017/07/10/about/">studies space and international security</a>, it is my job to ask what the likelihood of an object crashing into the planet really is – and whether governments are spending enough money to prevent such an event.</p>
<p>To find the answers to these questions, one has to know what near-Earth objects are out there. To date, NASA has tracked only an estimated <a href="https://www.nasa.gov/planetarydefense/faq">40% of the bigger ones</a>. Surprise asteroids have visited Earth in the past and will undoubtedly do so in the future. When they do appear, how prepared will humanity be?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/447112/original/file-20220217-1111-ukmxoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing thousands of blue orbits overlapping with Earth's own orbit." src="https://images.theconversation.com/files/447112/original/file-20220217-1111-ukmxoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/447112/original/file-20220217-1111-ukmxoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=511&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447112/original/file-20220217-1111-ukmxoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=511&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447112/original/file-20220217-1111-ukmxoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=511&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447112/original/file-20220217-1111-ukmxoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=643&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447112/original/file-20220217-1111-ukmxoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=643&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447112/original/file-20220217-1111-ukmxoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=643&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The orbits of thousands of asteroids (in blue) cross paths with the orbits of planets (in white), including Earth’s.</span>
<span class="attribution"><a class="source" href="https://apod.nasa.gov/apod/ap210829.html">NASA/JPL</a></span>
</figcaption>
</figure>
<h2>The threat from asteroids and comets</h2>
<p>Millions of objects of various sizes orbit the Sun. Near-Earth objects include asteroids and comets whose orbits will bring them <a href="https://cneos.jpl.nasa.gov/about/neo_groups.html">within 120 million miles</a> (193 million kilometers) of the Sun.</p>
<p>Astronomers consider a near-Earth object a threat if it will <a href="https://cneos.jpl.nasa.gov/about/neo_groups.html">come within 4.6 million miles</a> (7.4 million km) of the planet and is at least 460 feet (140 meters) in diameter. If a celestial body of this size crashed into Earth, it could destroy an entire city and cause extreme regional devastation. Larger objects - 0.6 miles (1 km) or more - could have global effects and even cause mass extinctions.</p>
<p>The most famous and destructive impact took place 65 million years ago when a 6-mile (10-km) diameter <a href="https://press.princeton.edu/books/paperback/9780691169668/t-rex-and-the-crater-of-doom">asteroid crashed into what is now the Yucatán Peninsula</a>. It <a href="https://doi.org/10.1126/science.1177265">wiped out most plant and animal species</a> on Earth, including the dinosaurs.</p>
<p>But smaller objects can also cause significant damage. In 1908, an approximately 164-foot (50-meter) celestial body exploded over the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0019103518305104?via%3Dihub">Tunguska</a> river in Siberia. It <a href="https://www.cbc.ca/news/science/the-tunguska-event-1.742329">leveled</a> more than 80 million trees over 830 square miles (2,100 square km). In 2013, an asteroid only 65 feet (20 meters) across burst in the atmosphere 20 miles (32 km) above Chelyabinsk, Russia. It released the equivalent of 30 Hiroshima bombs worth of energy, <a href="https://doi.org/10.1126/science.1242642">injured over 1,100 people</a> and caused US$33 million in damage.</p>
<p>The next asteroid of substantial size to potentially hit Earth is asteroid 2005 ED224. When the 164-foot (50-meter) asteroid passes by on March 11, 2023, there is roughly a <a href="https://cneos.jpl.nasa.gov/sentry/details.html#?des=2005%20ED224">1 in 500,000 chance of impact</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/447113/original/file-20220217-25-4n6zxf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graph showing the number of known large, medium and small near-Earth objects." src="https://images.theconversation.com/files/447113/original/file-20220217-25-4n6zxf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/447113/original/file-20220217-25-4n6zxf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447113/original/file-20220217-25-4n6zxf.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447113/original/file-20220217-25-4n6zxf.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447113/original/file-20220217-25-4n6zxf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447113/original/file-20220217-25-4n6zxf.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447113/original/file-20220217-25-4n6zxf.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">NASA has been steadily finding and tracking near-Earth objects since the 1990s.</span>
<span class="attribution"><a class="source" href="https://cneos.jpl.nasa.gov/stats/totals.html">NASA/JPL-Caltech</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Watching the skies</h2>
<p>While the <a href="https://trumpwhitehouse.archives.gov/wp-content/uploads/2021/01/NEO-Impact-Threat-Protocols-Jan2021.pdf">chances of a larger cosmic body impacting Earth are small</a>, the devastation <a href="http://mpainesyd.com/idisk/Public/rocks_from_space/chapman4oecd.pdf">would be enormous</a>.</p>
<p>Congress recognized this threat, and in <a href="https://archive.org/details/nasa_techdoc_19920025001">the 1998 Spaceguard Survey</a>, it tasked NASA to find and track 90% of near-Earth objects 0.6 miles (1 km) across or bigger within 10 years. NASA <a href="https://www.nasa.gov/mission_pages/WISE/multimedia/gallery/neowise/pia14734.html">surpassed the 90% goal</a> in 2011. </p>
<p>In 2005, <a href="https://www.govinfo.gov/content/pkg/STATUTE-119/pdf/STATUTE-119-Pg2895.pdf">Congress passed another bill</a> requiring NASA to expand its search and track at least 90% of all near-Earth objects 460 feet (140 meters) or larger by the end of 2020. That year has come and gone and, mostly due to <a href="https://www.nap.edu/catalog/12842/defending-planet-earth-near-earth-object-surveys-and-hazard-mitigation">a lack of financial resources</a>, only <a href="https://www.nasa.gov/planetarydefense/faq">40% of those objects have been mapped</a>. </p>
<p>As of Feb. 14, 2022, <a href="https://cneos.jpl.nasa.gov/stats/totals.html">astronomers have located 28,266</a> near-Earth asteroids, of which 10,033 are 460 feet (140 meters) or larger in diameter and 888 at least 0.6 miles (1 km) across. About <a href="https://www.nasa.gov/planetarydefense/faq">30 new objects</a> are added each week.</p>
<p>A new mission, <a href="https://www.congress.gov/bill/115th-congress/house-bill/5503/text#toc-HB5A37F19BF1E40DC8CF66F29EAE2DD66">funded by Congress in 2018</a>, is scheduled to launch in 2026 an infrared, <a href="https://www.nasa.gov/feature/nasa-approves-asteroid-hunting-space-telescope-to-continue-development">space-based telescope</a> – NEO Surveyor – dedicated to <a href="https://neos.arizona.edu/">searching for potentially dangerous asteroids</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Yl2f46L5DJ4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Smaller asteroids, like the one that exploded over Russia in 2013, can strike Earth without warning, but larger, more dangerous objects have surprised astronomers, too.</span></figcaption>
</figure>
<h2>Cosmic surprises</h2>
<p>We can only prevent a disaster if we know it is coming, and asteroids have sneaked up on Earth before. </p>
<p>An asteroid the size of a football field – dubbed the “City-killer” – passed <a href="https://www.washingtonpost.com/nation/2019/07/26/it-snuck-up-us-city-killer-asteroid-just-missed-earth-scientists-almost-didnt-detect-it-time/">less than 45,000 miles</a> from Earth in 2019. An asteroid the size of a 747 jet <a href="https://www.jpost.com/science/747-sized-asteroid-skimmed-by-earth-and-scientists-didnt-see-it-coming-680052">came close</a> in 2021 as did a 0.6-mile (1-km) wide <a href="https://www.space.com/16263-asteroid-2012lz1-size-earth-flyby.html">asteroid</a> in 2012. Each of these was discovered only <a href="https://www.esa.int/Safety_Security/Asteroid_s_surprise_close_approach_illustrates_need_for_more_eyes_on_the_sky">about a day</a> before they passed Earth. </p>
<p>Research suggests that one reason may be that Earth’s rotation <a href="https://doi.org/10.1016/j.icarus.2021.114735">creates a blind spot</a> whereby some asteroids remain undetected or appear stationary. This may be a problem, as some surprise asteroids do not miss us. In 2008, astronomers spotted a small <a href="https://cneos.jpl.nasa.gov/news/2008tc3.html">asteroid</a> only 19 hours before it crashed into rural Sudan. And the recent <a href="https://www.sciencealert.com/astronomers-have-discovered-a-surprise-asteroid-orbiting-between-mercury-and-venus">discovery</a> of an asteroid 1.2 miles (2 km) in diameter suggests that there are still big objects lurking.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/447115/original/file-20220217-15-mq01h6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A drawing of a spacecraft approaching two asteroids." src="https://images.theconversation.com/files/447115/original/file-20220217-15-mq01h6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/447115/original/file-20220217-15-mq01h6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/447115/original/file-20220217-15-mq01h6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/447115/original/file-20220217-15-mq01h6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/447115/original/file-20220217-15-mq01h6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/447115/original/file-20220217-15-mq01h6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/447115/original/file-20220217-15-mq01h6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">NASA’s DART mission will crash a small spacecraft into the double asteroid Didymos to see if it will change the asteroid’s orbit.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/image-feature/stay-tuned-for-dart">NASA/JHUAPL/Steve Gribben</a></span>
</figcaption>
</figure>
<h2>What can be done?</h2>
<p>To protect the planet from cosmic dangers, early detection is key. At the 2021 Planetary Defense Conference, scientists recommended a minimum of <a href="https://www.businessinsider.com/nasa-asteroid-simulation-reveals-need-years-of-warning-2021-5">five to 10 years’ preparation time</a> to mount a successful defense against hazardous asteroids. </p>
<p>If astronomers find a dangerous object, there are <a href="https://www.nap.edu/catalog/12842/defending-planet-earth-near-earth-object-surveys-and-hazard-mitigation">four ways</a> to mitigate a disaster. The first involves regional first-aid and evacuation measures. A second approach would involve sending a spacecraft to fly near a small- or medium-sized asteroid; the gravity of the craft would slowly change the object’s orbit. To <a href="https://www.nap.edu/catalog/12842/defending-planet-earth-near-earth-object-surveys-and-hazard-mitigation">change a bigger asteroid’s path</a>, we can either crash something into it at high speeds or detonate a nuclear warhead nearby.</p>
<p>These may seem like far-fetched ideas, but in November 2021, NASA launched the world’s first full-scale planetary defense mission as a proof of concept: the <a href="https://www.nasa.gov/planetarydefense/dart">Double Asteroid Redirection Test</a>, or DART. The <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/asteroids/didymos/in-depth/">large asteroid Didymos</a> and its small moon currently pose no threat to Earth. In September 2022, NASA plans to change the asteroid’s orbit by crashing a 1,340-pound (610 kg) probe into Didymos’ moon at a speed of approximately 14,000 mph (22,500 kph). </p>
<p>Learning more about what threatening asteroids are made of is also important, as their composition may affect how successful we are at deflecting them. The <a href="https://www.nasa.gov/feature/goddard/2020/bennu-top-ten">asteroid Bennu</a> is 1,620 feet (490 meters) in diameter. Its orbit will bring it dangerously close to Earth on Sept. 24, 2182, and there is a <a href="https://cneos.jpl.nasa.gov/sentry/details.html#?des=101955">1 in 2,700</a> chance of a collision. An asteroid of this size could wipe out an entire continent, so to learn more about Bennu, NASA launched the <a href="https://www.nasa.gov/osiris-rex">OSIRIS-Rex</a> probe in 2016. The spacecraft arrived at Bennu, took pictures, collected samples and is due to return to Earth in 2023. </p>
<p>[<em>Get the best of The Conversation, every weekend.</em> <a href="https://memberservices.theconversation.com/newsletters/?nl=weekly&source=inline-weeklybest">Sign up for our weekly newsletter</a>.]</p>
<h2>Spending on planetary defense</h2>
<p>In 2021, NASA’s planetary defense budget was <a href="https://www.nasa.gov/sites/default/files/atoms/files/updated_fy_2021_spend_plan_june_2021.pdf">$158 million</a>. This is just <a href="https://www.planetary.org/articles/nasas-planetary-defense-budget-growth">0.7%</a> of NASA’s <a href="https://www.nasa.gov/sites/default/files/atoms/files/fy2022_budget_summary.pdf">total budget</a> and just 0.02% of the roughly <a href="https://www.defense.gov/Spotlights/FY2021-Defense-Budget/">$700 billion 2021 U.S. defense budget</a>.</p>
<p>This budget supports a number of missions, including the NEO Surveyor at <a href="https://docs.google.com/spreadsheets/d/e/2PACX-1vSngWs2AJa9KoPByrpX-XUgqD6UcMdjl3IW1xAW-m3yCvjreNM6d9KFWkshhxE_sPW9JmgmsaV0NwbG/pubhtml">$83 million</a>, DART at <a href="https://www.planetary.org/space-policy/cost-of-dart">$324 million</a> and Osiris Rex at around <a href="https://www.planetary.org/space-policy/cost-of-osiris-rex">$1 billion</a> over several years.</p>
<p>Is this the right amount to invest in monitoring the skies, given the fact that some <a href="https://www.nasa.gov/planetarydefense/faq">60% of all potentially dangerous asteroids remain undetected</a>? This is an important question to ask when one considers the potential consequences.</p>
<p>Investing in planetary defense is akin to buying homeowners insurance. The likelihood of experiencing an event that destroys your house is very small, yet people buy insurance nonetheless.</p>
<p>If even a single object larger than 460 feet (140 meters) hits the planet, the devastation and loss of life would be extreme. A bigger impact could quite literally wipe out most species on Earth. Even if no such body is expected to hit Earth in the <a href="https://www.smithsonianmag.com/science-nature/the-very-real-effort-to-track-killer-asteroids-and-comets-180979206/">next 100 years</a>, the chance is not zero. In this low likelihood versus high consequences scenario, investing in protecting the planet from dangerous cosmic objects may give humanity some peace of mind and could prevent a catastrophe.</p><img src="https://counter.theconversation.com/content/177023/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The views expressed are those of the author and do not reflect the official position of the U.S. Department of Defense, or of any organization the author is affiliated with, including the Air University, Air War College, the U.S. Air Force and the U.S. Space Force.</span></em></p>NASA has only mapped 40% of the potentially dangerous asteroids that could crash into Earth. New projects will boost that number, and upcoming missions will test tech that could prevent collisions.Svetla Ben-Itzhak, Assistant Professor of Space and International Relations, West Space Seminar, Air War College, Air UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1491462020-12-31T20:19:52Z2020-12-31T20:19:52ZLook up! Your guide to some of the best meteor showers for 2021<figure><img src="https://images.theconversation.com/files/373826/original/file-20201209-14-1bho31j.jpg?ixlib=rb-1.1.0&rect=1401%2C485%2C4589%2C3368&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/ikewinski/49334338277/">Flickr/Mike Lewinski </a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>The best meteor showers are a spectacular sight but, unfortunately, 2021 starts with a whimper. Moonlight this January will wash out the first of the big three — the Quadrantids (seen above in 2020). </p>
<p>After that, the year just gets better and better, with the <a href="https://theconversation.com/look-up-your-guide-to-some-of-the-best-meteor-showers-for-2021-149146#term-Perseids">Perseids</a> (another of the big three along with the <a href="https://theconversation.com/look-up-your-guide-to-some-of-the-best-meteor-showers-for-2021-149146#term-Geminids">Geminids</a>) a particular highlight for northern hemisphere observers in August. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">Explainer: why meteors light up the night sky</a>
</strong>
</em>
</p>
<hr>
<p>In addition to the year’s other reliable performers we’ve included one wild card: the <a href="https://theconversation.com/look-up-your-guide-to-some-of-the-best-meteor-showers-for-2021-149146#term-Aurigids">Aurigids</a>, in late August. Most years, the Aurigids are a very, very minor shower, but they just might put on a show this year.</p>
<p>So here is our pick of the meteoric highlights for 2021.</p>
<p>For each meteor shower, we give you a finder chart showing the radiant (where the meteors appear to come from in the sky) and where best to look in the sky, the full period of activity and the forecast peak. Most meteor showers typically only yield their best rates for about a day around maximum, so the peak night is definitely the best to observe.</p>
<p>The Zenithal Hourly Rate <a href="https://www.amsmeteors.org/meteor-showers/meteor-faq/#7">ZHR</a> is the maximum number of meteors you would expect to see under perfect observing conditions. The actual number you will see will likely be lower.</p>
<p>Most meteor showers can only really be observed from either the northern [N] or southern [S] hemisphere, but a few are visible from both [N/S]. </p>
<h2><a id="term-Lyrids"></a>Lyrids [N/S; N favoured]</h2>
<h3>Active: April 14–30</h3>
<h3>Maximum: April 22, 1pm UTC = 11pm AEST (Qld) = 7am CST = 3am Hawaii time</h3>
<h3>ZHR: 18</h3>
<h3>Parent: <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/c-1861-g1-thatcher/in-depth/">Comet C/1861 G1 Thatcher</a></h3>
<p>The Lyrids are one of the meteor showers with the longest and most storied histories, with recorded observations <a href="https://www.space.com/36550-history-lyrid-meteor-shower-2017.html">spanning millenia</a>. In the past, they were one of the year’s most active showers, with a history of producing spectacular meteor storms.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373830/original/file-20201209-23-10rgdul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Flash of two meteors across a night sky." src="https://images.theconversation.com/files/373830/original/file-20201209-23-10rgdul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373830/original/file-20201209-23-10rgdul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=457&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373830/original/file-20201209-23-10rgdul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=457&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373830/original/file-20201209-23-10rgdul.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=457&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373830/original/file-20201209-23-10rgdul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=574&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373830/original/file-20201209-23-10rgdul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=574&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373830/original/file-20201209-23-10rgdul.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=574&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A couple of Lyrids.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/draconianrain/49805909916/">Flickr/DraconianRain</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Nowadays, the Lyrids are more sedate, putting on a reliable show without matching the year’s stronger showers. They still throw up occasional surprises such as an outburst in excess of 90 meteors per hour in 1982.</p>
<p>This year’s peak Lyrid rates coincide with the first quarter Moon, which will set around midnight, local time, for most locations. The best time to observe will come in the early hours of the morning, after moonset. </p>
<p>For observers in the northern hemisphere, the Lyrid radiant will already be at a useful altitude by the time the Moon is low in the sky, so some brighter meteors might be visible despite the moonlight in the late evening (after around 10:30pm, local time).</p>
<p>Once the Moon sets the sky will darken and make the shower much easier to observe, yielding markedly higher rates. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373541/original/file-20201208-14-ymq9n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373541/original/file-20201208-14-ymq9n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373541/original/file-20201208-14-ymq9n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=512&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373541/original/file-20201208-14-ymq9n9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=512&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373541/original/file-20201208-14-ymq9n9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=512&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373541/original/file-20201208-14-ymq9n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=643&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373541/original/file-20201208-14-ymq9n9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=643&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373541/original/file-20201208-14-ymq9n9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=643&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Across the US, the Lyrid radiant is high in the east before sunrise, above the Summer Triangle of Vega, Deneb and Altair. Low to the horizon, Jupiter and Saturn are rising. US around 4am local time.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>For observers in the southern hemisphere, the Lyrid radiant reaches a useful altitude in the early hours of the morning, when the Moon will have set. If you’re a keen meteor observer, it could be worth setting your alarm early to get out and watch the show for a few hours before dawn.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373536/original/file-20201208-19-zsnq1k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373536/original/file-20201208-19-zsnq1k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373536/original/file-20201208-19-zsnq1k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=476&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373536/original/file-20201208-19-zsnq1k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=476&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373536/original/file-20201208-19-zsnq1k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=476&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373536/original/file-20201208-19-zsnq1k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=598&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373536/original/file-20201208-19-zsnq1k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=598&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373536/original/file-20201208-19-zsnq1k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=598&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Boorong from north-western Victoria saw the Lyrids as Neilloan, the Mallee fowl, kicking up shooting stars while preparing her nest. Melbourne, 5am.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Lyrid meteors are fast and often quite bright so can be rewarding to observe, despite the relatively low rates (one every five or ten minutes, or so). Remember, this shower always has the potential to throw up an unexpected surprise.</p>
<h2><a id="term-Eta-Aquariids"></a>Eta Aquariids [S]</h2>
<h3>Active: April 19–May 28</h3>
<h3>Maximum: May 6, 3am UTC = 1pm AEST (Qld/NSW/ACT/Vic/Tas) = 11am AWST (WA)</h3>
<h3>ZHR: 50+</h3>
<h3>Parent: <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/1p-halley/in-depth/">Comet 1P/Halley</a></h3>
<p>The Eta Aquariids are an autumn treat for southern hemisphere observers. While not one of the big three, they stand clear as the best of the rest of the annual showers, yielding a fine display in the two or three hours before dawn.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Zgm-Z14_b3o?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The Eta Aquariids are fast meteors and are often bright, with smoky trains. They are fragments of the most famous comet, 1P/Halley, which has been laying down debris around its current orbit of the Sun for tens of thousands of years.</p>
<p>Earth passes through that debris twice a year, with the Eta Aquariids the best of the two meteor showers that result. The other is the Orionids, in October.</p>
<p>Where most meteor showers have a relatively short, sharp peak, the Eta Aquariids remain close to their best for a whole week, centred on the maximum. Good rates (ZHR > 30 per hour) should be visible before sunrise on each morning between May 3–10. </p>
<p>The Moon will be a waning crescent when the Eta Aquariids are at their best. Its glare should not interfere badly with the shower, washing out only the faintest members. </p>
<p>Observers who brave the pre-dawn hours to observe the Eta Aquariids will have the chance to lie beneath a spectacular sky. The Milky Way will be high overhead, with Jupiter, Saturn and the Moon high to the east and bright, fast meteors streaking across the sky from an origin near the eastern horizon.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373487/original/file-20201208-13-8crtu8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373487/original/file-20201208-13-8crtu8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373487/original/file-20201208-13-8crtu8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373487/original/file-20201208-13-8crtu8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373487/original/file-20201208-13-8crtu8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373487/original/file-20201208-13-8crtu8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=484&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373487/original/file-20201208-13-8crtu8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=484&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373487/original/file-20201208-13-8crtu8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=484&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The crescent Moon, the two biggest planets, a couple of bright stars and the Eta Aquariids all in the east before sunrise on May 6. Australia, around 4am local time.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<h2><a id="term-Perseids"></a>Perseids [N]</h2>
<h3>Active: July 17–August 24</h3>
<h3>Maximum: August 12, 7pm–10pm UTC = 8pm–11pm BST = August 13, 4am–7am JST</h3>
<h3>ZHR: 110</h3>
<h3>Parent: <a href="https://cometography.com/pcomets/109p.html">Comet 109P/Swift-Tuttle</a></h3>
<p>The Perseids are the meteoric highlight of the northern summer and the most observed shower of the year. December’s Geminids offer better rates but the timing of the Perseid peak makes them an ideal holiday treat.</p>
<p>The Perseids are debris shed behind by comet 109P/Swift-Tuttle, which is the largest known object (diameter around 26km) whose orbit currently intersects that of Earth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373832/original/file-20201209-17-b2p16v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An asteroid streak across the sky with a volcano and telescope in the foreground." src="https://images.theconversation.com/files/373832/original/file-20201209-17-b2p16v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373832/original/file-20201209-17-b2p16v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373832/original/file-20201209-17-b2p16v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373832/original/file-20201209-17-b2p16v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373832/original/file-20201209-17-b2p16v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373832/original/file-20201209-17-b2p16v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373832/original/file-20201209-17-b2p16v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A Perseid crosses the sky over the Teide volcano and Teide Observatory on Tenerife.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/starryearth/50221956782/">Flickr/StarryEarth</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Perseid meteors are fast, crashing into Earth at a speed of about 216,000km/h, and often bright. While the shower is active, at low levels, for more than a month, the best rates are typically visible for at the three nights centred on the peak. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373496/original/file-20201208-21-513eh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373496/original/file-20201208-21-513eh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373496/original/file-20201208-21-513eh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=214&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373496/original/file-20201208-21-513eh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=214&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373496/original/file-20201208-21-513eh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=214&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373496/original/file-20201208-21-513eh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=269&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373496/original/file-20201208-21-513eh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=269&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373496/original/file-20201208-21-513eh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=269&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Perseids radiate from the north-east, with the radiant rising high in the sky during the early hours of the morning. London, 11pm (left) and 4am (right)</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>For observers at European latitudes, the Perseid radiant rises by mid-evening, so the shower can be easily observed from 10pm local time, and remains high all through the night. The later in the night you look, the higher the radiant will be and the more meteors you’re likely to see.</p>
<h2><a id="term-Aurigids"></a>Aurigids [N favoured]</h2>
<h3>Active: August 28–September 5</h3>
<h3>Maximum: Potential Outburst on August 31, peaking between 9:15pm–9:40pm UTC = 10:15pm–10:40pm BST = 11:15pm–11:40pm CEST = September 1, 1:15am–1:40am Gulf Standard Time = September 1, 5:15am–5:40am AWST (WA)</h3>
<h3>ZHR: 50–100 (?)</h3>
<h3>Parent: <a href="https://www.newscientist.com/article/dn12443-rare-meteor-shower-to-shed-light-on-dangerous-comets/">Comet C/1911 N1 Kiess</a></h3>
<p>Where the other showers are reliable and relatively predictable, offering good rates every year, the Aurigids are an entirely different beast. </p>
<p>In most years, the shower is barely visible. Even at its peak, rates rarely exceed just a couple of meteors seen per hour. But occasionally the Aurigids bring a surprise with short and unexpected outbursts of 30-50 meteors an hour seen in 1935, 1986, 1994 and 2019.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/A1NF4jYWHnE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The parent comet of the Aurigids, C/1911 N1 Kiess, moves on an orbit with a period far longer than the parent of any other shower on our list.</p>
<p>It is thought the orbit takes between 1,800 and 2,000 years to complete, although our knowledge of it is very limited as it was only observed for a short period of time. </p>
<p>In late August every year, Earth passes through debris shed by the comet at a previous passage thousands of years into the past. In most years, the dust we encounter is very sparse.</p>
<p>But occasionally we intersect a denser, narrow stream of debris, material laid down at the comet’s previous passage. That dust has not yet had time to disperse so is more densely packed and hence gives enhanced rates: a meteor outburst.</p>
<p>Several independent research teams studying the past behaviour of the shower have all come to the same conclusion. On August 31, 2021, the Earth will once again intersect that narrow band of debris and <a href="https://www.imo.net/files/meteor-shower/cal2021.pdf#page=13">an outburst may occur</a>, with predictions it will peak around 21:17 UTC or 21:35 UTC.</p>
<p>Such an outburst would be short-lived. The dense core of the debris stream is so narrow it will take the Earth just ten or 20 minutes to traverse. So you’ll have to be lucky to see it.</p>
<p>The forecast outburst this year is timed such that observers in Eastern Europe and Asia will be the fortunate ones, with the radiant above the horizon. The waning Moon will light the sky when the radiant is above the horizon, washing out the fainter meteors from the shower. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373529/original/file-20201208-14-3vqtfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373529/original/file-20201208-14-3vqtfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373529/original/file-20201208-14-3vqtfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=463&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373529/original/file-20201208-14-3vqtfs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=463&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373529/original/file-20201208-14-3vqtfs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=463&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373529/original/file-20201208-14-3vqtfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=582&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373529/original/file-20201208-14-3vqtfs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=582&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373529/original/file-20201208-14-3vqtfs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=582&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">From Europe, the expected peak of the Aurigids occurs just before Moonrise. Be sure to look for the Pleiades whilst watching for any Aurigids - they’re a spectacular cluster of bright stars, commonly known as the Seven Sisters. Vienna, 11:30pm.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373534/original/file-20201208-15-ut3cbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373534/original/file-20201208-15-ut3cbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373534/original/file-20201208-15-ut3cbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=432&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373534/original/file-20201208-15-ut3cbo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=432&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373534/original/file-20201208-15-ut3cbo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=432&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373534/original/file-20201208-15-ut3cbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=542&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373534/original/file-20201208-15-ut3cbo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=542&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373534/original/file-20201208-15-ut3cbo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=542&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The crescent Moon has risen in Asia at the time the Aurigids peak. Dubai, 1:30am.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>The Aurigids tend to be fast and are often quite bright. Previous outbursts of the shower have featured large numbers of bright meteors. It may just be worth getting up and heading outside at the time of the predicted outburst, just in case the Aurigids give us a show to remember.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373523/original/file-20201208-17-s4nwed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373523/original/file-20201208-17-s4nwed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373523/original/file-20201208-17-s4nwed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373523/original/file-20201208-17-s4nwed.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373523/original/file-20201208-17-s4nwed.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373523/original/file-20201208-17-s4nwed.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373523/original/file-20201208-17-s4nwed.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373523/original/file-20201208-17-s4nwed.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">While waiting for the Aurigids, the morning sky in Perth is also packed with many famous constellations and bright stars. Perth, 5:30am.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<h2><a id="term-Geminids"></a>Geminids [N/S]</h2>
<h3>Active: December 4–17</h3>
<h3>Maximum: December 14, 7am UTC = 6pm AEDT (NSW/ACT/Vic/Tas) = 3pm AWST (WA) = 2am EST</h3>
<h3>ZHR: 150</h3>
<h3>Parent: Asteroid <a href="https://echo.jpl.nasa.gov/asteroids/Phaethon/Phaethon_planning.2017.html">3200 Phaethon</a></h3>
<p>The Geminid meteor shower is truly a case of saving the best until last. By far the best of the annual meteor showers, it graces our skies every December, yielding good numbers of spectacular, bright meteors.</p>
<p>The shower is so good it is always worth observing, even in 2021, when the Moon will be almost full.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/UCX5GqWMzxs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Over the decades, the Geminids have gradually become stronger and stronger. They took the crown of the year’s best shower from the Perseids in the 1990s, and have continued to improve ever since.</p>
<p>For observers in the northern hemisphere, the Geminids are visible from relatively early in the evening, with their radiant rising shortly after sunset, and remaining above the horizon for all of the hours of darkness.</p>
<p>As the night progresses, the radiant gets very high in the sky and the shower can put on a truly spectacular show.</p>
<p>For those in the southern hemisphere, the situation is not quite as ideal. The further south you live, the later the radiant will rise, and so the later the show will begin.</p>
<p>When the radiant reaches its highest point in the sky (around 2am–3am local time), it sits closer to the horizon the further south you are, so the best meteor rates you observe will be reduced compared to those seen from more northerly locations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373553/original/file-20201208-17-85h9ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373553/original/file-20201208-17-85h9ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373553/original/file-20201208-17-85h9ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=225&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373553/original/file-20201208-17-85h9ns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=225&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373553/original/file-20201208-17-85h9ns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=225&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373553/original/file-20201208-17-85h9ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=283&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373553/original/file-20201208-17-85h9ns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=283&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373553/original/file-20201208-17-85h9ns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=283&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">At its highest point, the Geminids radiant sits higher from Brisbane (left) than from Hobart (right), which is why northern observers have a better chance of seeing more meteors.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Despite these apparent drawbacks, the Geminids are still by far the best meteor shower of the year for observers in Australia, and are well worth a look, even on the moonlit nights of 2021.</p>
<p>Peak Geminid rates last for around 24 hours, centred on the official peak time, before falling away relatively rapidly thereafter. This means that observers around the globe can enjoy the display.</p>
<p>The best rates come when the radiant is highest in the sky (around 2–3am) but it is well worth looking up at any time after the radiant has risen above the horizon.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/373559/original/file-20201208-23-1hsn82a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/373559/original/file-20201208-23-1hsn82a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373559/original/file-20201208-23-1hsn82a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373559/original/file-20201208-23-1hsn82a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373559/original/file-20201208-23-1hsn82a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373559/original/file-20201208-23-1hsn82a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373559/original/file-20201208-23-1hsn82a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373559/original/file-20201208-23-1hsn82a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">The Geminid radiant rises at about the following times across Australia.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>So wherever you are on the planet, if skies are clear for the peak of the Geminids, it is well worth going outside and looking up, to revel in the beauty of the greatest of the annual meteor showers.</p><img src="https://counter.theconversation.com/content/149146/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A poor start for meteor showers in 2021 but things get better with a possible spectacular surprise later in the year. Here’s your guide on when and where to look to catch nature’s fireworks.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandTanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1259362020-01-02T21:56:17Z2020-01-02T21:56:17ZLook up! Your guide to some of the best meteor showers for 2020<figure><img src="https://images.theconversation.com/files/306459/original/file-20191211-95159-vh28cj.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1024%2C671&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A composite image of one night watching the Orionids meteor shower.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/jeffreysullivan/30356513802/">Flickr/Jeff Sullivan</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Where 2019 was a disappointing year for meteor showers, with two of the big three (the Quadrantids, Perseids and Geminids) lost mainly to moonlight, 2020 promises to be much better.</p>
<p>The year starts with a bang with the Quadrantids providing a treat for northern hemisphere viewers. The Perseids, in August, provide another highlight for those in the northern hemisphere, while the December Geminids round the year off for observers all around the world.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">Explainer: why meteors light up the night sky</a>
</strong>
</em>
</p>
<hr>
<p>But the big three aren’t the only meteor showers that will put on a show this year. So when should you look up to see the meteoric highlights of the coming year?</p>
<p>Here’s our pick of the showers to watch. We have the time each shower is forecast to peak, finder charts showing you where best to look, and the theoretical peak rates you could see under ideal observing conditions. This is a number known as the Zenithal Hourly Rate (<a href="https://www.amsmeteors.org/meteor-showers/meteor-faq/#7">ZHR</a>).</p>
<p>Because the ZHR is the theoretical maximum rate you could see per hour, it is likely that the rates you observe will be lower. </p>
<p>For any meteor shower, if you want to give yourself the best chance to see a good display, it is worth trying to find a <a href="http://darksitefinder.com/map/">good dark site</a>, as far from light polluted skies as possible. Once you’re outside give yourself plenty of <a href="https://www.telescope.com/Articles/Equipment/Binoculars/Seeing-in-the-Dark/pc/9/c/192/sc/195/p/99833.uts">time to adapt to the darkness</a>, at least half an hour. Then just sit back, relax, and enjoy the show.</p>
<p>Showers that can only really be seen from either the northern or southern hemisphere are denoted by [N] or [S], whilst those that can be seen from both are marked by [N/S].</p>
<blockquote>
<p>You can <a href="https://cdn.theconversation.com/static_files/files/810/TC_2020_meteor_shower_guide.zip?1576116275">download a ICS file</a> of this guide to add to your favourite calender.</p>
</blockquote>
<h2><a id="term-quadrantids"></a>Quadrantids [N]</h2>
<h3>Active: December 28 - January 12</h3>
<h3>Maximum: January 4, 8:20am UTC = 8:20am GMT = 3:20am EST = 12:20am PST</h3>
<h3>ZHR: 120 (variable, can reach ~200)</h3>
<h3>Parent: It’s complicated… (Comet <a href="http://cometography.com/pcomets/096p.html">96P/Macholz</a> and asteroid <a href="https://doi.org/10.1051/0004-6361/201322228" title="Meteor-shower complex of asteroid 2003 EH1 compared with that of comet 96P/Machholz">2003 EH1</a>)</h3>
<p>The Quadrantids are the first of the big three meteor showers of the year – the three showers that give fabulous displays with ZHRs in excess of 100, year in, year out. </p>
<p>For most of the fortnight over which the Quadrantids are active, rates are low - just a few meteors per hour. In the hours approaching their peak, rates climb rapidly, before falling away just as rapidly once the peak is past. In total, rates exceed a quarter of their maximum value for just eight hours, centred on the peak.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306016/original/file-20191210-95149-qmco12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306016/original/file-20191210-95149-qmco12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306016/original/file-20191210-95149-qmco12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306016/original/file-20191210-95149-qmco12.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306016/original/file-20191210-95149-qmco12.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306016/original/file-20191210-95149-qmco12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306016/original/file-20191210-95149-qmco12.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306016/original/file-20191210-95149-qmco12.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">From Vancouver, as the Quadrantids reach their peak, the radiant is low to the horizon, but it moves higher in the east as dawn approaches [Vancouver midnight].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>The Quadrantid radiant is <a href="https://earthsky.org/space/what-are-circumpolar-stars">circumpolar (never sets)</a> for locations north of 40 degrees north. As a result, the shower can be observed throughout the hours of darkness for most locations in Europe and many in North America.</p>
<p>The radiant lies in the constellation <a href="https://www.constellation-guide.com/constellation-list/bootes-constellation/">Boötes</a>, the Herdsman, relatively near the tail of <a href="https://www.constellation-guide.com/constellation-list/ursa-major-constellation/">Ursa Major</a>, the Plough or Great Bear.</p>
<p>The radiant rises highest in the sky in the early hours of the morning, so this is when the best rates can be seen. In 2020, the shower’s peak favours observers in the east of North America, though those in northern Europe should see a good display in the hours before dawn on the morning of January 4.</p>
<p>If skies are clear it is definitely worth wrapping up warm and heading out to observe the most elusive of the year’s big three.</p>
<h2><a id="term-lyrids"></a>Lyrids [N/S; N preferred]</h2>
<h3>Active: April 14 – 30</h3>
<h3>Maximum: Variable – between April 21, 10:40pm UTC and April 22, 9:40am UTC (April 22 9:40am UTC = 4:40am EST = 1:40am PST)</h3>
<h3>ZHR: 18 (variable, can reach ~90)</h3>
<h3>Parent: <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/c-1861-g1-thatcher/in-depth/">Comet C/1861 G1 Thatcher</a></h3>
<p>The Lyrids are a shower with a long and storied history – with records reporting their activity <a href="https://www.space.com/36550-history-lyrid-meteor-shower-2017.html">tracing back for millennia</a>. Researchers have even suggested the Lyrids may have been active on Earth for <a href="https://ui.adsabs.harvard.edu/abs/1997MNRAS.289..721A/abstract" title="The mean orbit of the April Lyrids">more than a million years</a>.</p>
<p>In the distant past, there are reports the Lyrids produced some spectacular displays – meteor storms, with thousands of meteors visible per hour.</p>
<p>The modern Lyrids are usually more sedate, with peak rates rarely exceeding ~18 meteors per hour. But they do sometimes throw up the odd surprise. An outburst of the Lyrids in 1982 yielded rates of ~90 meteors per hour for a short period. </p>
<p>While no such outburst is forecast this year, the peak of the shower will occur just a day before a new Moon, so skies will be dark and viewing conditions ideal.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306017/original/file-20191210-95120-1ajzikc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306017/original/file-20191210-95120-1ajzikc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306017/original/file-20191210-95120-1ajzikc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=505&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306017/original/file-20191210-95120-1ajzikc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=505&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306017/original/file-20191210-95120-1ajzikc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=505&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306017/original/file-20191210-95120-1ajzikc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=635&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306017/original/file-20191210-95120-1ajzikc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=635&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306017/original/file-20191210-95120-1ajzikc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=635&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">From the USA, the radiant is well placed from late evening through the morning hours [Chicago 11pm]</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Although the Lyrids are best seen from the northern hemisphere, their radiant can reach a useful altitude for observers in the northern half of Australia. Keen observers might be tempted to head out in the early hours of the morning to watch. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306020/original/file-20191210-95153-8a4rjo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306020/original/file-20191210-95153-8a4rjo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306020/original/file-20191210-95153-8a4rjo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306020/original/file-20191210-95153-8a4rjo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306020/original/file-20191210-95153-8a4rjo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306020/original/file-20191210-95153-8a4rjo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306020/original/file-20191210-95153-8a4rjo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306020/original/file-20191210-95153-8a4rjo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Across Australia, the Lyrids are best seen in the hour before sunrise, when the radiant is at its highest [Brisbane, 5am].</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>The radiant rises during the night so the best rates are seen in the early hours of the morning, before dawn. From northern hemisphere sites, reasonable rates can be seen after about 10:30pm, local time -– but for those at southern hemisphere latitudes, the radiant fails to reach a reasonable altitude until well after midnight.</p>
<p>Lyrid meteors tend to be relatively fast and are often bright. Despite the relatively low rates (at least, compared to the big three) they are well worth a watch, especially as conditions this year will be as close to perfect as possible.</p>
<h2><a id="term-eta-aquariids"></a>Eta Aquariids [S]</h2>
<h3>Active: April 19 – May 28</h3>
<h3>Maximum: May 5, 9pm UTC = May 6, 7am AEST (Qld/NSW/ACT/Vic/Tas) = May 6, 4am AWST (WA) = May 6, 6am JST</h3>
<h3>ZHR: 50+</h3>
<h3>Parent: <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/1p-halley/in-depth/">Comet 1P/Halley</a></h3>
<p>While not counted as one of the big three, in many ways the Eta Aquariids stand clear of the pack as the best of the rest.</p>
<p>Only really visible to observers in the tropics and the southern hemisphere, the Eta Aquariids are fragments of the most famous of comets –- Halley’s comet. They mark the first (and best) of two passages made by the Earth through the debris laid down by that comet over thousands of years –- with the other being the Orionids, in October.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306022/original/file-20191210-95111-1m2val2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306022/original/file-20191210-95111-1m2val2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306022/original/file-20191210-95111-1m2val2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=564&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306022/original/file-20191210-95111-1m2val2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=564&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306022/original/file-20191210-95111-1m2val2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=564&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306022/original/file-20191210-95111-1m2val2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=708&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306022/original/file-20191210-95111-1m2val2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=708&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306022/original/file-20191210-95111-1m2val2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=708&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Look to the east before sunrise and catch the Eta Aquariids along with Jupiter, Saturn, and Mars too [Melbourne 5am].</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>The radiant only rises a few hours before dawn, even at southern altitudes, and the further north you go, the closer to sunrise the radiant appears. This is what prevents northern hemisphere observers from taking advantage of the Eta Aquariids –- the Sun has risen by the time the radiant is high enough for the shower to put on a decent show.</p>
<p>The meteors are fast and often bright, and the brighter ones have a reputation for leaving behind noticeable smoky trains. The maximum of the shower is broad, with rates remaining above ~30 meteors per hour for the week around the date of the maximum.</p>
<p>It is well worth getting out to observe the Eta Aquariids at around the time their radiant rises. This gives the maximum amount of time to observe the shower before dawn, but in addition, those few meteors you observe when the radiant is sitting just above the horizon can be spectacular.</p>
<p>Known as Earthgrazers, such meteors enter the atmosphere at a very shallow angle, with the result that they can streak all the way across the sky, from horizon to horizon.</p>
<p>The Eta Aquariids reach their peak in 2020 a couple of days before the full Moon. That the radiant does not rise until a few hours before sunrise works to our advantage this year –- the shower’s radiant will rise at around the same time the Moon sets, so the shower can be observed in Moon-free skies, despite the proximity of the Full Moon.</p>
<h2><a id="term-perseids"></a>Perseids [N]</h2>
<h3>Active: July 17 – August 24</h3>
<h3>Maximum: August 12, 1pm - 4pm UTC = 3am - 6am HST = 10pm - August 13, 1am JST + filament passage ~3 hours before the main peak</h3>
<h3>ZHR: 110</h3>
<h3>Parent: <a href="https://cometography.com/pcomets/109p.html">Comet 109P/Swift-Tuttle</a></h3>
<p>For northern hemisphere observers, the Perseids are perhaps the famous and reliable shower of the year.</p>
<p>While the Geminids offer higher rates, the Perseids fall during the middle of the northern summer, when families are often holidaying and the weather is warm and pleasant. As a result, the Perseids are the most widely observed of all meteor showers, and never fail to put on a spectacular show.</p>
<p>The parent comet of the Perseid meteor shower, 109P/Swift-Tuttle, was last at perihelion (closest to the Sun) in 1991. As a result, during the 1990s, the Perseids offered enhanced rates –- often displaying multiple peaks through the two or three days around their traditional maximum.</p>
<p>Those individual peaks were the result of the Earth passing through individual trails of material, laid down at past perihelion passages of the comet, which have not yet had time to fully disperse into the background of the shower as a whole.</p>
<p>It is now three decades since the comet’s last perihelion passage, but astronomers predict the Earth could well pass through one of those debris trails this year, at around 10am UTC (midnight Hawaii time, 3am Vancouver time), three hours before the normal forecast maximum for the shower.</p>
<p>As a result, peak rates should last for longer, and potentially reach higher values than would normally be expected from a typical Perseid return.</p>
<p>The radiant rises in the mid-evening from northern latitudes, which means the shower can be observed from around 10pm or 11pm, local time. The later in the night you look, the higher the radiant will be, and so the more meteors will be visible.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306023/original/file-20191210-95125-1vvbfup.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306023/original/file-20191210-95125-1vvbfup.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306023/original/file-20191210-95125-1vvbfup.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=419&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306023/original/file-20191210-95125-1vvbfup.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=419&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306023/original/file-20191210-95125-1vvbfup.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=419&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306023/original/file-20191210-95125-1vvbfup.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306023/original/file-20191210-95125-1vvbfup.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306023/original/file-20191210-95125-1vvbfup.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=527&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This year it’s best to catch the Perseids early in the evening before the Moon rises [Greenwich 9pm].</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Unfortunately, the peak of the Perseids in 2020 falls two days after the last quarter Moon, which means moonlight will begin to interfere with the display in the early hours of the morning. The best views of the shower will likely be seen between ~10pm or 11pm local time and ~2am the following morning. </p>
<p>If you can only observe in the hours before dawn, all is not lost. The Perseids are famed for producing plenty of bright meteors. They are worth observing even when the Moon is above the horizon, particularly on the nights around the forecast peak.</p>
<h2><a id="term-orionids"></a>Orionids [N/S]</h2>
<h3>Active: October 2 – November 7</h3>
<h3>Maximum: October 21</h3>
<h3>ZHR: 20+</h3>
<h3>Parent: <a href="https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/1p-halley/in-depth/">1P/Halley</a></h3>
<p>The Orionid meteor shower marks the second occasion the Earth encounters the stream of debris left behind by Halley’s comet each year. </p>
<p>In October, Earth passes farther from the centre of Halley’s debris stream than in May, with the result the observed rates for the Orionids are lower than for the Eta Aquariids. Despite this, the Orionids remain a treat for meteor enthusiasts in the northern autumn and southern spring.</p>
<p>The Orionids peak on October 21 but that maximum is often quite broad with activity hovering close to the peak rates for as much as a week around the maximum.</p>
<p>There is some evidence the peak rates vary over time, with a roughly 12 year periodicity, as a result of perturbations by the giant planet Jupiter (which orbits the Sun once every 12 years).</p>
<p>In the final years of the first decade of the 21st Century, the Orionids were markedly more active than expected, with maximum rates in the range 40-70. If the periodicity is real, then 12 years on from the peak of activity it is possible the Orionids will again put on a better than expected show.</p>
<p>So 2020 might well be an ideal year to look up and watch for fragments of Halley’s Comet vapourising high overhead.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306038/original/file-20191210-95159-c7448d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306038/original/file-20191210-95159-c7448d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306038/original/file-20191210-95159-c7448d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=625&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306038/original/file-20191210-95159-c7448d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=625&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306038/original/file-20191210-95159-c7448d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=625&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306038/original/file-20191210-95159-c7448d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=785&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306038/original/file-20191210-95159-c7448d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=785&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306038/original/file-20191210-95159-c7448d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=785&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Before dawn, Orion stands upright in the south as seen from the northern hemisphere [Vancouver 5am].</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>The radiant rises just before local midnight, meaning the meteors are best observed in the early hours of the morning. The radiant reaches its highest altitude in the hours before dawn. The Moon will not interfere this year, setting in the early evening, long before the radiant rises.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306039/original/file-20191210-95111-jwts67.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306039/original/file-20191210-95111-jwts67.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306039/original/file-20191210-95111-jwts67.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=565&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306039/original/file-20191210-95111-jwts67.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=565&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306039/original/file-20191210-95111-jwts67.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=565&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306039/original/file-20191210-95111-jwts67.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=710&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306039/original/file-20191210-95111-jwts67.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=710&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306039/original/file-20191210-95111-jwts67.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=710&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The view from the southern hemisphere finds Orion upside in the northern sky before sunrise.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Observers watching the Orionids are in for an extra treat. While the Orionids are active, so too are the Northern and Southern Taurid meteor showers. Where the Orionids are fast meteors, Taurids are slow, and often bright and spectacular.</p>
<p>Although the rates of both the Northern and Southern Taurids are lower than those of the Orionids (typically just ~5 per hour), their activity makes observations of the Orionids even more productive and exciting.</p>
<h2><a id="term-geminids"></a>Geminids [N/S]</h2>
<h3>Active: December 4 – 17</h3>
<h3>Maximum: December 14, 12:50am UTC = 11:50am AEDT (NSW/ACT/Vic/Tas) = 8:50am AWST (WA) = 5:50pm EST (evening of December 13)</h3>
<h3>ZHR: 150</h3>
<h3>Parent: Asteroid <a href="https://echo.jpl.nasa.gov/asteroids/Phaethon/Phaethon_planning.2017.html">3200 Phaethon</a></h3>
<p>The Geminids, which peak in mid-December, are truly a case of saving the best until last. The biggest of the year’s big three, the Geminids have, over the past few decades, been growing ever more active and spectacular, with recent years seeing rates in excess of 150 per hour.</p>
<p>For observers in northern Europe, the radiant is above the horizon relatively soon after sunset, meaning that the Geminids can readily be observed from around 8pm onwards.</p>
<p>The further south you travel, the later in the evening the radiant rises. For observers in Australia, the times at which the radiant appears above the horizon can be seen below.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306495/original/file-20191212-85397-15utob8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306495/original/file-20191212-85397-15utob8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306495/original/file-20191212-85397-15utob8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306495/original/file-20191212-85397-15utob8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306495/original/file-20191212-85397-15utob8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306495/original/file-20191212-85397-15utob8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306495/original/file-20191212-85397-15utob8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306495/original/file-20191212-85397-15utob8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Geminid radiant rises at about the following times across Australia.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>As with all showers, the higher the radiant in the sky, the better the observed rates from the Geminids will be. The longer you watch, the better things will get.</p>
<p>Geminid meteors are of medium speed and often bright so they put on a spectacular show even in those years when moonlight interferes.</p>
<p>In 2020 the Moon will be new around this time so it will be possible to spend the entire night watching the Geminids without any interference from our nearest celestial neighbour.</p>
<p>The radiant reaches its highest at around 2am local time making the hours just after midnight the ideal time to catch the Geminids at their best.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/306026/original/file-20191210-95138-jcektp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/306026/original/file-20191210-95138-jcektp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/306026/original/file-20191210-95138-jcektp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=628&fit=crop&dpr=1 600w, https://images.theconversation.com/files/306026/original/file-20191210-95138-jcektp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=628&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/306026/original/file-20191210-95138-jcektp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=628&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/306026/original/file-20191210-95138-jcektp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=789&fit=crop&dpr=1 754w, https://images.theconversation.com/files/306026/original/file-20191210-95138-jcektp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=789&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/306026/original/file-20191210-95138-jcektp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=789&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Geminids will put on a show during the early hours of the December 14 [Perth 2am; Sydney 3am]</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>The Geminid peak is relatively broad -– with rates remaining high for at least 24 hours around the forecast maximum. Observers across the globe will be treated to a spectacular display from the shower in 2020. </p>
<p>So find a dark site, wrap up warm, and treat yourself to a night spent watching the year’s most spectacular display of natural fireworks.</p><img src="https://counter.theconversation.com/content/125936/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A big year ahead for some of the meteor showers this year. Here’s your 2020 guide on when and where to look to catch nature’s fireworks.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandTanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1176722019-05-24T04:49:57Z2019-05-24T04:49:57ZWhat caused the fireballs that lit up the sky over Australia?<figure><img src="https://images.theconversation.com/files/276288/original/file-20190524-187176-14x502.png?ixlib=rb-1.1.0&rect=0%2C0%2C998%2C585&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">One of the fireballs (highlighted by the red circle) captured over the Northern Territory.</span> <span class="attribution"><span class="source">NT Emergency Services</span></span></figcaption></figure><p>Over the past few days a pair of spectacular fireballs have graced Australia’s skies.</p>
<p>The first, in the early hours of Monday, May 20, <a href="https://www.abc.net.au/news/2019-05-20/meteor-over-central-australia-cctv-police-weather-light-bright/11129714">flashed across the Northern Territory, and was seen from both Tennant Creek and Alice Springs</a>, more than 500km apart. </p>
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<p>The second came <a href="https://www.abc.net.au/news/2019-05-22/suspected-meteor-spotted-across-the-sky-in-south-australia/11136648">two days later, streaking over South Australia and Victoria</a>.</p>
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<p>Such fireballs are not rare events, and serve as yet another reminder that Earth sits in a celestial shooting gallery. In addition to their spectacle, they hold the key to understanding the Solar system’s formation and history. </p>
<h2>Crash, bang, boom!</h2>
<p>On any clear night, if you gaze skyward long enough, <a href="https://theconversation.com/look-up-your-guide-to-some-of-the-best-meteor-showers-for-2019-106863">you will see meteors</a>. These flashes of light are the result of objects impacting on our planet’s atmosphere.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/look-up-your-guide-to-some-of-the-best-meteor-showers-for-2019-106863">Look up! Your guide to some of the best meteor showers for 2019</a>
</strong>
</em>
</p>
<hr>
<p>Specks of debris <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">vaporise harmlessly in the atmosphere, 80-100km above our heads</a>, all the time – <a href="https://www.nasa.gov/mission_pages/asteroids/overview/fastfacts.html">about 100 tons of the stuff per day</a>.</p>
<p>The larger the object, the more spectacular the flash. Where your typical meteor is caused by an object the size of a grain of dust (or, for a particularly bright one, a grain of rice), fireballs like those seen this week are caused by much larger bodies – the size of a grapefruit, a melon or even a car.</p>
<p>Such impacts are rarer than their tiny siblings because there are many more small objects in the Solar system than larger bodies.</p>
<p><a href="https://theconversation.com/why-dangerous-asteroids-heading-to-earth-are-so-hard-to-detect-113845">Moving to still larger objects</a>, you get truly spectacular but rare events like the incredible <a href="https://theconversation.com/forensic-astronomy-the-russian-meteor-and-2012-da14-12266">Chelyabinsk fireball in February 2013</a>. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/ztrU90Ub4Uw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>That was probably the <a href="https://theconversation.com/chelyabinsk-meteor-explosion-a-wake-up-call-scientists-warn-19874">largest impact on Earth for 100 years</a>, and caused plenty of damage and injuries. It was the result of the explosion of an object 10,000 tonnes in mass, around 20 metres in diameter.</p>
<p>On longer timescales, the largest impacts are truly enormous. Some 66 million years ago, a comet or asteroid around 10km in diameter ploughed into what is now the Yucatan Peninsula, Mexico. The result? A crater some 200km across, and a <a href="https://theconversation.com/how-the-dinosaurs-went-extinct-asteroid-collision-triggered-potentially-deadly-volcanic-eruptions-112134">mass extinction that included the dinosaurs</a>.</p>
<p>Even that is not the largest impact Earth has experienced. Back in our planet’s youth, it was victim to a truly cataclysmic event, when it collided with an object the size of Mars. </p>
<p>When the dust and debris cleared, our once solitary planet was accompanied by the <a href="https://theconversation.com/was-our-two-faced-moon-in-a-small-collision-2659">Moon</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/o2lRpiediP8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The story behind the formation of the Moon.</span></figcaption>
</figure>
<p>Impacts that could threaten life on Earth are, thankfully, very rare. While <a href="https://theconversation.com/why-dangerous-asteroids-heading-to-earth-are-so-hard-to-detect-113845">scientists are actively searching to make sure no extinction-level impacts are coming in the near future</a>, it really isn’t something we should lose too much sleep about.</p>
<p>Smaller impacts, like those seen earlier this week, come far more frequently - indeed, footage of another <a href="https://www.space.com/bright-meteor-fireball-illinois-police-video-may-2019.html">fireball was reported</a> earlier this month over Illinois in the United States. </p>
<p>In other words, it is not that unusual to have two bright fireballs in the space of a couple of days over a country as vast as Australia. </p>
<h2>Pristine relics of planet formation</h2>
<p>These bright fireballs can be an incredible boon to our understanding of the formation and evolution of the Solar system. When an object is large enough, it is possible for fragments (or the whole thing) to penetrate the atmosphere intact, delivering a new meteorite to our planet’s surface.</p>
<p>Meteorites are incredibly valuable to scientists. They are celestial time capsules – relatively pristine fragments of asteroids and comets that formed when the Solar system was young.</p>
<p>Most meteorites we find have lain on Earth for long periods of time before their discovery. These are termed “finds” and while still valuable, are often degraded and weathered, chemically altered by our planet’s wet, warm environment. </p>
<p>By contrast, “falls” (meteorites whose fall has been observed and that are recovered within hours or days of the event) are far more precious. When we study their composition, we can be confident we are studying something ancient and pristine, rather than worrying that we’re seeing the effect of Earth’s influence.</p>
<h2>Tracking the fireballs</h2>
<p>For this reason, the <a href="http://fireballsinthesky.com.au/">Australian Desert Fireball Network</a> has set up an enormous network of cameras across our vast continent. These cameras are designed to scour the skies, all night, every night, watching for fireballs like those seen earlier this week.</p>
<p>If we can observe such a fireball from multiple directions, we can triangulate its path, calculate its motion through the atmosphere, and work out whether it is likely to have dropped a meteorite. Using that data, <a href="https://theconversation.com/how-to-find-a-meteorite-thats-fallen-to-earth-52906">we can even work out where to look</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Ls0QXPpmD2M?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A successful meteorite search by the Australian Desert Fireball Network.</span></figcaption>
</figure>
<p>In addition to these cameras, the project can make use of any data provided by people who saw the event. For that reason, the Fireballs team developed a <a href="http://fireballsinthesky.com.au/report-a-fireball/">free app, Fireballs in the Sky</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-we-solved-the-mystery-of-libyan-desert-glass-117253">How we solved the mystery of Libyan desert glass</a>
</strong>
</em>
</p>
<hr>
<p>It contains great information about fireballs and meteor showers, and has links to experiments tied into the national curriculum. More importantly, it also allows its users to submit their own fireball reports.</p>
<p>As for this week’s fireball over southern Australia, NASA says it was probably caused by an object <a href="https://www.abc.net.au/news/2019-05-23/nasa-says-meteor-soaring-to-earth-was-the-size-of-a-small-car/11141760">the size of a small car</a>. As for finding any remains, they are now likely lost in the waters of the Great Australian Bight.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/276275/original/file-20190524-187147-nrv4id.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/276275/original/file-20190524-187147-nrv4id.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/276275/original/file-20190524-187147-nrv4id.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=335&fit=crop&dpr=1 600w, https://images.theconversation.com/files/276275/original/file-20190524-187147-nrv4id.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=335&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/276275/original/file-20190524-187147-nrv4id.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=335&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/276275/original/file-20190524-187147-nrv4id.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=420&fit=crop&dpr=1 754w, https://images.theconversation.com/files/276275/original/file-20190524-187147-nrv4id.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=420&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/276275/original/file-20190524-187147-nrv4id.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=420&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">NASA’s record on the location marked in the Great Australian Bight of one of the fireballs over Australia this week.</span>
<span class="attribution"><a class="source" href="https://cneos.jpl.nasa.gov/fireballs/">NASA</a></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/117672/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonti Horner does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Security cameras captured two separate fireballs over Australia this week. So what’s responsible these bright flashes?Jonti Horner, Professor (Astrophysics), University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1172532019-05-22T19:48:16Z2019-05-22T19:48:16ZHow we solved the mystery of Libyan desert glass<figure><img src="https://images.theconversation.com/files/275324/original/file-20190520-69169-1pwuxu4.jpg?ixlib=rb-1.1.0&rect=0%2C216%2C2945%2C1819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A collection of raw Libyan desert glass.</span> <span class="attribution"><span class="source">Linnas/Shutterstock </span></span></figcaption></figure><p>In the remote desert of western Egypt, near the Libyan border, lie clues to an ancient cosmic cataclysm. </p>
<p>Libyan desert glass is the name given to fragments of canary-yellow glass found scattered over hundreds of kilometres, between giant shifting sand dunes. </p>
<p>Interest in Libyan desert glass goes back more than 3,000 years. Among items recovered from King Tut’s burial chamber is a <a href="http://gem.gov.eg/index/Gallery%20-G1_3.htm">gold and jewel-encrusted breastplate</a>. In the centre sits a beautiful scarab beetle, carved from Libyan desert glass.</p>
<p>Libyan desert glass – raw and carved – is <a href="https://www.ebay.com/b/Libyan-Desert-Glass/3239/bn_55190490">easily available today</a>, but how the glass formed has long puzzled scientists.</p>
<p>Our <a href="https://pubs.geoscienceworld.org/gsa/geology/article/570318/overestimation-of-threat-from-100-mt-class" title="Overestimation of threat from 100 Mt–class airbursts? High-pressure evidence from zircon in Libyan Desert Glass">research</a> has found the answer.</p>
<h2>The heat is on</h2>
<p><a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1945-5100.1996.tb02017.x" title="New fission‐track age determinations on impact glasses">Studies</a> show the Libyan desert glass formed about 29 million years ago. The glass is nearly pure silica, which requires temperatures above 1,600°C to form, and that is hotter than any igneous rock on Earth. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/274879/original/file-20190516-69204-dttve2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/274879/original/file-20190516-69204-dttve2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274879/original/file-20190516-69204-dttve2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=257&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274879/original/file-20190516-69204-dttve2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=257&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274879/original/file-20190516-69204-dttve2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=257&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274879/original/file-20190516-69204-dttve2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=323&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274879/original/file-20190516-69204-dttve2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=323&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274879/original/file-20190516-69204-dttve2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=323&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Optical light images of a thin slice of Libyan desert glass.</span>
<span class="attribution"><span class="source">Aaron J Cavosie</span></span>
</figcaption>
</figure>
<p>But few mineral relics survived from whatever caused the melting. Within the glass are rare occurrences of high-temperature minerals, including a form of quartz called cristobalite.</p>
<p>There are also grains of the mineral zircon, although most have reacted to form a higher-temperature mineral called <a href="https://theconversation.com/a-disappointing-earring-and-the-worlds-hottest-rock-zirconia-97084">zirconia</a>.</p>
<p>Ideas about how the glass formed include melting during meteorite impact, or melting caused by an airburst from an asteroid or other object burning up high in Earth’s atmosphere.</p>
<p>Despite many studies, definitive proof about which origin is correct has been elusive, until now. </p>
<p>One problem is that no impact crater from any object hitting the ground in the area has been identified as the source of the glass. Another was the lack of evidence of damage from high-pressure shock waves caused by any impact. </p>
<h2>Evidence of impact</h2>
<p>Our research, <a href="https://pubs.geoscienceworld.org/gsa/geology/article/570318/overestimation-of-threat-from-100-mt-class" title="Overestimation of threat from 100 Mt–class airbursts? High-pressure evidence from zircon in Libyan Desert Glass">published in the journal Geology</a>, reports the first evidence of high-pressure damage, showing the glass formed during a meteorite impact.</p>
<p>Meteorite impacts and airbursts are both catastrophic events. Large meteorite impacts, such as the one that <a href="https://www.nationalgeographic.com/science/prehistoric-world/dinosaur-extinction/">killed the dinosaurs</a> more than 65 million years ago, are rare.</p>
<p>But airbursts occur more frequently. An <a href="https://news.nationalgeographic.com/news/2013/11/131106-russian-meteor-chelyabinsk-airburst-500-kilotons/">airburst over Chelyabinsk</a>, Russia, in 2013 caused extensive property damage and injured people.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/tq02C_3FvFo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Boom!</span></figcaption>
</figure>
<p>The Chelyabinsk airburst <a href="https://www.theguardian.com/science/2013/nov/06/chelyabinsk-meteor-russia">deposited 0.5 megatons of energy</a> into the sky. Despite the damage, that event did not cause melting or shock damage.</p>
<p>In contrast, Libyan desert glass is thought by some to have been caused by a 100-megaton airburst, an event 200 times larger than the Russian airburst.</p>
<p>The airburst idea arose from modelling atmospheric nuclear explosions. Like a nuclear bomb, a large airburst deposits energy into the atmosphere that can melt surface materials. And an airburst does not leave a crater.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/target-earth-how-asteroids-made-an-impact-on-australia-92836">Target Earth: how asteroids made an impact on Australia</a>
</strong>
</em>
</p>
<hr>
<h2>The ‘smoking gun’</h2>
<p>The new “smoking gun” for understanding the origin of the Libyan desert glass is evidence of an unusual mineral called reidite. Reidite only forms during a meteorite impact, when atoms in the mineral zircon are forced into a tighter arrangement.</p>
<p>Such high-pressure minerals are a hallmark of a meteorite impact, and do not form during airbursts.</p>
<p>Zircon is a common mineral in granite, sandstone and other rock types. It is known from Earth, the Moon, Mars, and various meteorites. It is widely used for dating when rocks formed.</p>
<p>Zircon is also useful when searching for evidence of shock deformation caused by a meteorite impact. At low shock intensity, zircon deforms by bending of the crystal. It is like bending a plastic spoon to the point where it deforms but does not break.</p>
<p>As the shock intensity increases, zircon further responds in several unique ways and at extreme pressures, reidite forms. </p>
<p>If the rocks then get hot, zircon will recrystallise. This results in the formation of a network of new, tiny interlocking grains. Above 1,700°C zircon ultimately breaks down to zirconia. </p>
<p>Libyan desert glass contains many zircon grains, all smaller than the width of a human hair. While most reacted to zirconia due to the heat, about 10% preserve evidence of former reidite. But the thing is, reidite is no longer present.</p>
<p>Reidite is not stable when hot, and reverts back to zircon above 1,200°C. It only gets preserved if shocked rocks do not melt. So it takes a specialised technique called electron backscatter diffraction to nut out whether reidite once existed in shocked zircons that got hot. </p>
<p>The key to finding evidence of <a href="https://pubs.geoscienceworld.org/gsa/geology/article/46/10/891/548169/" title="FRIGN zircon—The only terrestrial mineral diagnostic of high-pressure and high-temperature shock deformation">former reidite</a> lies in analysing the crystal orientations of the tiny interlocking grains in reverted zircon.</p>
<p>Similar to turning a Rubik’s cube, the initial transformation to reidite occurs along specific directions in a zircon crystal. When reidite changes back to zircon, it leaves a fingerprint of its existence that can be detected through orientation analysis. </p>
<p>And we found the reidite fingerprint in samples of the Libyan desert glass. We examined zircon grains from seven samples and the critical crystal orientation evidence of former reidite was present in each sample.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/275583/original/file-20190521-23835-10b4w9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/275583/original/file-20190521-23835-10b4w9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275583/original/file-20190521-23835-10b4w9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=437&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275583/original/file-20190521-23835-10b4w9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=437&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275583/original/file-20190521-23835-10b4w9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=437&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275583/original/file-20190521-23835-10b4w9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=549&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275583/original/file-20190521-23835-10b4w9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=549&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275583/original/file-20190521-23835-10b4w9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=549&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A closer look at Libyan desert glass: The colors indicate the crystal orientations of tiny interlocking grains of recrystallised zircon. A recrystallized zircon with no history of reidite would be the same color.</span>
<span class="attribution"><span class="source">Aaron J Cavosie</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A meteor impact</h2>
<p>Reidite is rare and only reported from meteorite impact sites. It is found in material <a href="https://pubs.geoscienceworld.org/gsa/geology/article/43/10/899/131727/" title="Precambrian reidite discovered in shocked zircon from the Stac Fada impactite, Scotland">ejected</a> from craters and in shocked <a href="https://pubs.geoscienceworld.org/gsa/geology/article/43/4/315/131844/" title="Nanoscale records of ancient shock deformation: Reidite (ZrSiO4) in sandstone at the Ordovician Rock Elm impact crater">rocks</a> at craters.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-disappointing-earring-and-the-worlds-hottest-rock-zirconia-97084">A disappointing earring, and the world's hottest rock: zirconia</a>
</strong>
</em>
</p>
<hr>
<p>Prior studies have found evidence of former reidite within zircon from <a href="https://www.sciencedirect.com/science/article/pii/S0016703718306513" title="A new U-Pb age for shock-recrystallised zircon from the Lappajärvi impact crater, Finland, and implications for the accurate dating of impact events">impact melt</a>, similar to how it was identified in Libyan desert glass.</p>
<p>A 100 megaton airburst should occur <a href="https://www.sciencedirect.com/science/article/pii/S0094576513003500" title="Airburst warning and response">every 10,000 years</a>. If this size event is supposed to have caused Libyan desert glass to form, the geological record does not support the idea. The reidite fingerprint points to a meteor impact as the only option.</p>
<p>Outstanding mysteries about Libyan desert glass still remain, such as the location of the source crater, its size, and determining if it has eroded away.</p><img src="https://counter.theconversation.com/content/117253/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aaron J. Cavosie receives funding from the Australian Research Council for work not related to this study.</span></em></p>The origin of Libyan desert glass found scattered in an Egyptian desert has puzzled scientists for years. But a new look at the glass structure reveals its meteoric formation.Aaron J. Cavosie, Senior research fellow, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1144082019-04-01T12:51:01Z2019-04-01T12:51:01ZCurious Kids: what are meteorites made of and where do they come from?<figure><img src="https://images.theconversation.com/files/266793/original/file-20190401-177167-gu4cs5.jpg?ixlib=rb-1.1.0&rect=0%2C497%2C4000%2C2694&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/falling-meteorite-asteroid-comet-on-earth-1071396749">Shutterstock.</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a> is a series by <a href="https://theconversation.com/uk">The Conversation</a>, which gives children of all ages the chance to have their questions about the world answered by experts. All questions are welcome: you or an adult can send them – along with your name, age and town or city where you live – to curiouskids@theconversation.com. We won’t be able to answer every question, but we’ll do our best.</em></p>
<hr>
<blockquote>
<p><strong><em>What is a meteorite made of and where do they come from? – the children of Year Five at Leigh St. Mary’s Church of England Primary School, Lancashire, UK.</em></strong></p>
</blockquote>
<p>Meteorites are “space rocks”, which are found on Earth after they fall from the sky. While falling, these space rocks race through the air a hundred times faster than an airplane. Travelling this fast makes the space rocks very hot – more than 1000°C! And that makes them shine, like a star – which is why people call them “shooting stars”. </p>
<p>Most meteors are tiny, and burn up as they fall toward Earth. Some bigger ones explode. This happened in 2013 in Russia: a meteor as large a house exploded above a city of more than a million people. </p>
<iframe src="https://giphy.com/embed/WwYewJG2tmiMI8jTsS" width="100%" height="270" frameborder="0" class="giphy-embed" allowfullscreen=""></iframe>
<p>Some space rocks hit the Earth. This can make a hole in the ground, making what we call a crater. The Earth’s moon is covered with craters, but craters on Earth are usually washed away by rain, or plants grow over them, or they get wiped away when mountains grow. You can still find some pretty big craters on Earth, though, such as the <a href="https://www.britannica.com/place/Meteor-Crater">Barringer crater</a> in Arizona, US. </p>
<p>It’s a miracle no one has been hit on the head by one of these space rocks. But many dinosaurs weren’t that lucky 65m years ago, when a rock the size of London <a href="https://www.manchester.ac.uk/discover/news/stunning-fossil-find-records-the-last-day-of-the-dinosaurs/">struck Earth</a>. This meteor made the gigantic Chicxulub crater, caused a huge tsunami wave, turned day into night – and it’s the main reason why dinosaurs went extinct. </p>
<h2>What are meteors made of?</h2>
<p>Surely, you’d think, meteors can’t be just like normal stones – well, yes and no. They come in two different types. </p>
<p>One is a bit like stone, and it can be difficult to tell if it’s a meteorite. </p>
<p>The other is like a clump of metal, much heavier than normal stone. These are easier to recognise. Both types have a “skin” that is scorched, as if it had been in a very hot oven. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/266819/original/file-20190401-177184-w9aaki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/266819/original/file-20190401-177184-w9aaki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/266819/original/file-20190401-177184-w9aaki.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/266819/original/file-20190401-177184-w9aaki.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/266819/original/file-20190401-177184-w9aaki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/266819/original/file-20190401-177184-w9aaki.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/266819/original/file-20190401-177184-w9aaki.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A piece of the Allende meteorite – see its scorched skin?</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:AllendeMeteorite.jpg">H. Raab/Wikimedia Commons.</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Where do meteors come from?</h2>
<p>We know there are many rocks that go all the way around the sun, just like the Earth does over the course of one year. The largest one is almost a thousand kilometres wide. It’s called <a href="https://spacedictionary.org/ceres/">Ceres</a>. But many of the smaller ones humans can’t see … until they hit Earth! </p>
<p>Some of these rocks are called “asteroids”, because they shine like stars. Others are called “comets” because they are more like dirty snowballs that leave a trail behind them. </p>
<p>Asteroids and comets are the crumbles left over after planets like Earth formed, <a href="https://phys.org/news/2014-12-earth.html">4.5 billion years</a> ago. Some were also made when two planets crashed into each other. </p>
<p>Many planets, including Earth, are stony on the outside and metallic on the inside. And this explains why meteorites come in two types: the stony ones come from the outsides of those unlucky planets that got in a crash, while the metallic ones come from their insides. </p>
<p>Earth itself <a href="https://moon.nasa.gov/about/in-depth/">got hit</a> when it was still only millions of years young, and that’s how the moon was made.</p>
<h2>Meteors from Mars and beyond</h2>
<p>When a big meteorite makes a crater, it throws up rocks into space. Those rocks can also land on Earth. Some meteorites come from the moon, and some even <a href="https://www2.jpl.nasa.gov/snc/">from Mars</a>. We know that because inside the meteorites are tiny bubbles of air. The air on Mars is very different from the air on Earth, so we can tell if a rock comes from Mars by <a href="http://science.sciencemag.org/content/338/6108/785">examining the air bubbles</a> inside. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/266820/original/file-20190401-177178-1pwi62b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/266820/original/file-20190401-177178-1pwi62b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/266820/original/file-20190401-177178-1pwi62b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/266820/original/file-20190401-177178-1pwi62b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/266820/original/file-20190401-177178-1pwi62b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/266820/original/file-20190401-177178-1pwi62b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/266820/original/file-20190401-177178-1pwi62b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">‘Oumuamua in flight.</span>
<span class="attribution"><span class="source">ESO/M. Kornmesser.</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Some rocks even come from outside of our solar system. Scientists spotted the first one of these in 2017 – it’s called <a href="https://theconversation.com/how-i-discovered-the-origins-of-the-cigar-shaped-alien-asteroid-oumuamua-89577">‘Oumuamua</a>, and it’s a hundred metres wide. Luckily, it missed Earth. </p>
<p>Plants, animals and insects are all very different creatures. But all life on Earth shares something special, and that’s extremely tiny bits called amino acids. And they have been <a href="https://www.scientificamerican.com/article/murchison-meteorite/">found inside meteorites</a>! Scientists still aren’t quite sure what this means exactly, but some believe life might have arrived on Earth from space – if that turns out to be true, perhaps we’re all aliens, after all?</p>
<hr>
<p><em>More <a href="https://theconversation.com/topics/curious-kids-36782?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">Curious Kids</a> articles, written by academic experts:</em></p>
<ul>
<li><p><em><a href="https://theconversation.com/curious-kids-why-do-we-have-fingernails-and-toenails-110989?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">Why do we have fingernails and toenails? – Jake (age 9) and Ben (age 7), Melbourne, Australia.</a></em></p></li>
<li><p><em><a href="https://theconversation.com/curious-kids-how-do-currents-form-under-water-111882?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">How do currents form under water? – Natalie, age 11, Melksham, UK.</a></em></p></li>
<li><p><em><a href="https://theconversation.com/curious-kids-is-there-a-place-in-the-middle-of-the-english-channel-where-the-waves-change-direction-101562?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=CuriousKidsUK">Is there a place in the middle of the English Channel where the waves change direction? – Sebastian, age 12, Kent, UK.</a></em></p></li>
</ul><img src="https://counter.theconversation.com/content/114408/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jacco van Loon does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Meteorites might look like boring bits of rock – but each one has a fascinating story.Jacco van Loon, Astrophysicist and Director of Keele Observatory, Keele UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1138452019-03-22T06:27:14Z2019-03-22T06:27:14ZWhy dangerous asteroids heading to Earth are so hard to detect<figure><img src="https://images.theconversation.com/files/265255/original/file-20190322-195118-1fa6jbl.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3339%2C2057&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How close can a potentially dangerous asteroid get before it's detected?</span> <span class="attribution"><span class="source">Shutterstock/Alexyz3d</span></span></figcaption></figure><p>Earth is often in the firing line of fragments of asteroids and comets, most of which <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">burn up</a> tens of kilometres above our heads. But occasionally, something larger gets through. </p>
<p>That’s what happened off Russia’s east coast on December 18 last year. A <a href="https://www.bbc.com/news/science-environment-47607696">giant explosion occurred above the Bering Sea</a> when an asteroid some ten metres across detonated with an explosive energy ten times greater than the bomb dropped on Hiroshima.</p>
<p>So why didn’t we see this asteroid coming? And why are we only hearing about its explosive arrival now?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/look-up-your-guide-to-some-of-the-best-meteor-showers-for-2019-106863">Look up! Your guide to some of the best meteor showers for 2019</a>
</strong>
</em>
</p>
<hr>
<h2>Nobody saw it</h2>
<p>Had the December explosion occurred near a city – as <a href="https://www.theguardian.com/world/2013/feb/15/hundreds-injured-meteorite-russian-city-chelyabinsk">happened at Chelyabinsk in February 2013</a> – we would have heard all about it at the time.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/fBLjB5qavxY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Plenty of people observed and captured the Chelyabinsk meteor explosion.</span></figcaption>
</figure>
<p>But because it happened in a remote part of the world, it went unremarked for more than three months, until details were unveiled at the <a href="https://www.hou.usra.edu/meetings/lpsc2019/">50th Lunar and Planetary Science Conference</a> this week, based on <a href="https://cneos.jpl.nasa.gov/fireballs/">NASA’s collection of fireball data</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/265251/original/file-20190322-195097-jsp81r.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/265251/original/file-20190322-195097-jsp81r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/265251/original/file-20190322-195097-jsp81r.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=342&fit=crop&dpr=1 600w, https://images.theconversation.com/files/265251/original/file-20190322-195097-jsp81r.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=342&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/265251/original/file-20190322-195097-jsp81r.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=342&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/265251/original/file-20190322-195097-jsp81r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=430&fit=crop&dpr=1 754w, https://images.theconversation.com/files/265251/original/file-20190322-195097-jsp81r.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=430&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/265251/original/file-20190322-195097-jsp81r.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=430&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The 173kt fireball blast off Russia’s eastern coastline in December was the largest recorded since 2013’s fireball over the Russian city of Chelyabinsk.</span>
<span class="attribution"><a class="source" href="https://cneos.jpl.nasa.gov/fireballs/">NASA/JPL-Caltech/Center for Near Earth Object Studies</a></span>
</figcaption>
</figure>
<p>So where did this asteroid come from?</p>
<h2>At risk from space debris</h2>
<p>The Solar system is littered with material left over from the formation of the planets. Most of it is locked up in stable reservoirs – the Asteroid belt, the Edgeworth-Kuiper belt and the Oort cloud – far from Earth. </p>
<p>Those reservoirs continually leak objects into interplanetary space, injecting fresh debris into orbits that cross those of the planets. The inner Solar system is awash with debris, ranging from tiny flecks of dust to comets and asteroids many kilometres in diameter.</p>
<p>The vast majority of the debris that collides with Earth is utterly harmless, but our planet still <a href="https://theconversation.com/target-earth-how-asteroids-made-an-impact-on-australia-92836">bears the scars of collisions</a> with much larger bodies. </p>
<p>The largest, most devastating impacts (like that which <a href="https://theconversation.com/how-the-dinosaurs-went-extinct-asteroid-collision-triggered-potentially-deadly-volcanic-eruptions-112134">helped to kill the dinosaurs</a> 65 million years ago) are the rarest. But smaller, more frequent collisions also pose a marked risk.</p>
<p>In 1908, in Tunguska, Siberia, a <a href="http://www.bbc.com/earth/story/20160706-in-siberia-in-1908-a-huge-explosion-came-out-of-nowhere">vast explosion</a> levelled more than 2,000 square kilometres of forest. Due to the remote location, no deaths were recorded. Had the impact happened just two hours later, the city of St Petersburg could have been destroyed.</p>
<p>In 2013, it was a 10,000-tonne asteroid that <a href="https://earthsky.org/space/meteor-asteroid-chelyabinsk-russia-feb-15-2013">detonated above the Russian city of Chelyabinsk</a>. More than 1,500 people were injured and around 7,000 buildings were damaged, but amazingly nobody was killed. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/265252/original/file-20190322-195110-17x1ynm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/265252/original/file-20190322-195110-17x1ynm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/265252/original/file-20190322-195110-17x1ynm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=325&fit=crop&dpr=1 600w, https://images.theconversation.com/files/265252/original/file-20190322-195110-17x1ynm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=325&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/265252/original/file-20190322-195110-17x1ynm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=325&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/265252/original/file-20190322-195110-17x1ynm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=408&fit=crop&dpr=1 754w, https://images.theconversation.com/files/265252/original/file-20190322-195110-17x1ynm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=408&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/265252/original/file-20190322-195110-17x1ynm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=408&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The meteor trail taken about 200km away from Chelyabinsk a minute after the blast in 2013.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/alexeya/8475569087/">Flickr/Alex Alishevskikh</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We’re still trying to work out how often events like this happen. Our information on the frequency of the larger impacts is pretty limited, so estimates can vary dramatically.</p>
<p>Typically, people argue that Tunguska-sized impacts happen <a href="https://academic.oup.com/astrogeo/article/50/1/1.18/201316">every few hundred years</a>, but that’s just based on a sample of one event. The truth is, we don’t really know.</p>
<h2>What can we do about it?</h2>
<p>Over the past couple of decades, a concerted effort has been made to search for potentially hazardous objects that pose a threat before they hit Earth. The result is the <a href="https://cneos.jpl.nasa.gov/stats/totals.html">identification of thousands of near-Earth asteroids</a> upwards of a few metres across.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/pF5ffUhUbHI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Once found, the orbits of those objects can be determined, and their paths <a href="https://cneos.jpl.nasa.gov/ca/">predicted into the future</a>, to see whether an impact is possible or even likely. The longer we can observe a given object, the better that prediction becomes. </p>
<p>But as we saw with Chelyabinsk in 2013, and again in December, we’re not there yet. While the catalogue of potentially hazardous objects continues to grow, many still remain undetected, waiting to catch us by surprise.</p>
<p>If we discover a collision is pending in the coming days, we can work out where and when the collision will happen. That happened for the first time in 2008 when astronomers discovered the tiny <a href="https://cneos.jpl.nasa.gov/news/2008tc3.html">asteroid 2008 TC3</a>, 19 hours before it hit Earth’s atmosphere over northern Sudan. </p>
<p>For impacts predicted with a longer lead time, it will be possible to work out whether the object is truly dangerous, or would merely produce a spectacular but harmless fireball (like 2008 TC3).</p>
<p>For any objects that truly pose a threat, the race will be on to deflect them – to turn a hit into a miss.</p>
<h2>Searching the skies</h2>
<p>Before we can quantify the threat an object poses, we first need to know that the object is there. But finding asteroids is hard.</p>
<p>Surveys scour the skies, <a href="https://spaceguardcentre.com/what-are-neos/finding-and-observing-asteroids/">looking for faint star-like points moving against the background stars</a>. A bigger asteroid will reflect more sunlight, and therefore appear brighter in the sky - at a given distance from Earth. </p>
<p>As a result, the smaller the object, the closer it must be to Earth before we can spot it.</p>
<p>Objects the size of the Chelyabinsk and Bering Sea events (about 20 and 10 metres diameter, respectively) are tiny. They can only be spotted when passing very close to our planet. The vast majority of the time they are simply undetectable.</p>
<p>As a result, having impacts like these come out of the blue is really the norm, rather than the exception!</p>
<p>The Chelyabinsk impact is a great example. Moving on its orbit around the Sun, it approached us in the daylight sky - totally hidden in the Sun’s glare. </p>
<p>For larger objects, which impact much less frequently but would do far more damage, it is fair to expect we would receive some warning.</p>
<h2>Why not move the asteroid?</h2>
<p>While we need to keep searching for threatening objects, there is another way we could protect ourselves.</p>
<p>Missions such as <a href="https://solarsystem.nasa.gov/missions/hayabusa/in-depth/">Hayabusa</a>, <a href="http://www.hayabusa2.jaxa.jp/en/">Hayabusa 2</a> and <a href="https://www.asteroidmission.org/">OSIRIS-REx</a> have demonstrated the ability to travel to near-Earth asteroids, land on their surfaces, and move things around. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/265259/original/file-20190322-36273-1tgxglt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/265259/original/file-20190322-36273-1tgxglt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/265259/original/file-20190322-36273-1tgxglt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/265259/original/file-20190322-36273-1tgxglt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/265259/original/file-20190322-36273-1tgxglt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/265259/original/file-20190322-36273-1tgxglt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/265259/original/file-20190322-36273-1tgxglt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/265259/original/file-20190322-36273-1tgxglt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This artist’s concept shows the OSIRIS-REx spacecraft contacting the asteroid Bennu.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/image-feature/osiris-rex-grabs-a-sample">NASA's Goddard Space Flight Center</a></span>
</figcaption>
</figure>
<p>From there, it is just a short hop to being able to deflect them – to change a potential collision into a near-miss. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-the-dinosaurs-went-extinct-asteroid-collision-triggered-potentially-deadly-volcanic-eruptions-112134">How the dinosaurs went extinct: asteroid collision triggered potentially deadly volcanic eruptions</a>
</strong>
</em>
</p>
<hr>
<p>Interestingly, ideas of asteroid deflection dovetail nicely with the <a href="https://theconversation.com/mining-asteroids-could-unlock-untold-wealth-heres-how-to-get-started-95675">possibility of asteroid mining</a>.</p>
<p>The technology needed to extract material from an asteroid and send it back to Earth could equally be used to alter the orbit of that asteroid, moving it away from a potential collision with our planet.</p>
<p>We’re not quite there yet, but for the first time in our history, we have the potential to truly control our own destiny.</p><img src="https://counter.theconversation.com/content/113845/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonti Horner does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We’re finding more near-Earth objects all the time, and the challenge is to identify those that could potentially hit us. So how come we missed one that caused a huge blast in December?Jonti Horner, Professor (Astrophysics), University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1068632018-12-31T21:07:59Z2018-12-31T21:07:59ZLook up! Your guide to some of the best meteor showers for 2019<figure><img src="https://images.theconversation.com/files/251105/original/file-20181217-185255-1g6x1vi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The 2018 Geminids meteor shower recorded over two very cold hours on the slope of Mount Lütispitz, Switzerland.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/lschlagenhauf/45425029645/">Flickr/Lukas Schlagenhauf</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>The year gets off to a bang with the Quadrantids, the first of the annual big three <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">meteor showers</a>. Active while the Moon is new, it gives northern hemisphere observers a show to enjoy during the cold nights of winter. Sadly, the shower is not visible from southern skies.</p>
<p>The other two members of the big three — the Perseids and Geminids — are not so fortunate this year, with moonlight set to interfere and reduce their spectacle. </p>
<p>So, with that in mind, where and when should you observe to make the best of 2019’s meteoric offerings? Here we present the likely highlights for this year – the showers most likely to put on a good show.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">Explainer: why meteors light up the night sky</a>
</strong>
</em>
</p>
<hr>
<p>We provide details of the full forecast activity period for each shower, and the forecast time of maximum. We also give sky charts, showing you where best to look, and give the theoretical peak rates that could be seen under ideal observing conditions – a number known as the Zenithal Hourly Rate, or <a href="https://www.amsmeteors.org/meteor-showers/meteor-faq/#7">ZHR</a>.</p>
<p>It is important to note that the ZHR is the theoretical maximum number of meteors you would expect to see per hour for a given shower, unless it were to catch us by surprise with an unexpected outburst!</p>
<p>In reality, the rates you observe will be lower than the ZHR – but the clearer and darker your skies, and the higher the shower’s radiant in the sky, the closer you will come to this ideal value.</p>
<p>For any shower, to see the best rates, it is worth trying to find a <a href="http://darksitefinder.com/map/">good dark site (the darker the better)</a> – far from streetlights and other illuminations. Once you’re outside, give your eyes plenty of time to adapt to the dark - <a href="https://www.telescope.com/Articles/Equipment/Binoculars/Seeing-in-the-Dark/pc/9/c/192/sc/195/p/99833.uts">half an hour should do the trick</a>.</p>
<p>Showers that can only really be seen from one hemisphere or the other are denoted by either [N] or [S], while those that can be seen globally are marked as [N/S].</p>
<blockquote>
<p>You can <a href="https://calendar.google.com/calendar/ical/theconversation.com_e0dofqra13ht6g6stianlnhkvk%40group.calendar.google.com/public/basic.ics">download this ics file</a> and add to your calendar to stay informed on when the meteor showers are due.</p>
</blockquote>
<h2><a id="term-quadrantids"></a>Quadrantids [N]</h2>
<h3>Active: December 28 - January 12</h3>
<h3>Maximum: January 4, 2:20am UT = 2:20am GMT = 3:20am CET</h3>
<h3>ZHR: 120 (variable, can reach ~200)</h3>
<h3>Parent: It’s complicated (comet <a href="http://cometography.com/pcomets/096p.html">96P/Macholz</a> and asteroid <a href="https://doi.org/10.1051/0004-6361/201322228">2003 EH1</a>)</h3>
<p>Despite being one of this year’s three most active annual showers, the Quadrantids are often overlooked and under-observed. This is probably the result of their peak falling during the depths of the northern hemisphere winter, when the weather is often less than ideal for meteor observations.</p>
<p>For most of the fortnight they are active, Quadrantid rates are very low (less than five per hour). The peak itself is very short and sharp, far more so than for the year’s other major showers. As a result, rates exceed a quarter of the maximum ZHR for a period of just eight hours, centred on the peak time. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/249566/original/file-20181210-72514-eqzq6w.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/249566/original/file-20181210-72514-eqzq6w.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249566/original/file-20181210-72514-eqzq6w.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249566/original/file-20181210-72514-eqzq6w.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249566/original/file-20181210-72514-eqzq6w.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249566/original/file-20181210-72514-eqzq6w.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249566/original/file-20181210-72514-eqzq6w.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249566/original/file-20181210-72514-eqzq6w.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Quadrantid radiant lies in the northern constellation Boötes, relatively near the tail of Ursa Major, the Great Bear. The radiant is shown here at around midnight, local time, as it begins to climb higher in the northeastern sky.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium, Author provided</span></span>
</figcaption>
</figure>
<p>The Quadrantid radiant lies in the northern constellation Boötes, the Herdsman, and is circumpolar (never sets) for observers poleward of 40 degrees north. As a result, observers in northern Europe and Canada can see Quadrantids at any time of night. The radiant is highest in the sky (and the rates are best) in the hours after midnight. </p>
<p>For this reason, this year’s peak (at 2:20am UT) is best suited for observers in northern Europe - and given that peak rates can exceed 100 per hour, it is certainly worth setting the alarm for, to get up in the cold early hours, and watch the spectacle unfold.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/251110/original/file-20181217-185261-1gxrqy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/251110/original/file-20181217-185261-1gxrqy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/251110/original/file-20181217-185261-1gxrqy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=455&fit=crop&dpr=1 600w, https://images.theconversation.com/files/251110/original/file-20181217-185261-1gxrqy0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=455&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/251110/original/file-20181217-185261-1gxrqy0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=455&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/251110/original/file-20181217-185261-1gxrqy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=572&fit=crop&dpr=1 754w, https://images.theconversation.com/files/251110/original/file-20181217-185261-1gxrqy0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=572&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/251110/original/file-20181217-185261-1gxrqy0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=572&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This false-color composite image shows a combination of Quadrantid and non-Quadrantid meteors streaking through the skies over NASA’s Marshall Space Flight Center, in the US, on the night of January 3-4, 2012.</span>
<span class="attribution"><span class="source">NASA/MSFC/Meteoroid Environments Office/Danielle Moser and Bill Cooke</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2><a id="term-alpha-centaurids"></a>Alpha Centaurids [S]</h2>
<h3>Active: January 31 - February 20</h3>
<h3>Maximum: February 8, 1:00pm UT = February 8, 9pm (WA) = February 8, 11pm (Qld) = February 9, 12am (NSW/ACT/Vic/Tas)</h3>
<h3>ZHR: Variable; typically 6, but can exceed 25</h3>
<h3>Parent: Unknown</h3>
<p>The Alpha Centaurids are a minor meteor shower, producing typical rates of just a few meteors per hour. But they are famed as a source of spectacular fireballs for southern hemisphere observers and so are worth keeping an eye out for in southern summer skies.</p>
<p>Alpha Centaurids are fast meteors, and are often bright. As with most showers that are only visible from the southern hemisphere, they remain poorly studied. Though typically yielding low rates, several outbursts have occurred where rates reached or exceeded 25 per hour. </p>
<p>The shower’s radiant lies close to the bright star Alpha Centauri – the closest naked-eye star to the Solar System and the third brightest star in the night sky.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/250835/original/file-20181217-185258-a9sukf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/250835/original/file-20181217-185258-a9sukf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/250835/original/file-20181217-185258-a9sukf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/250835/original/file-20181217-185258-a9sukf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/250835/original/file-20181217-185258-a9sukf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/250835/original/file-20181217-185258-a9sukf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/250835/original/file-20181217-185258-a9sukf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/250835/original/file-20181217-185258-a9sukf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Alpha Centaurids are well placed for the southern hemisphere. This view from Brisbane around the time of maximum activity.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Alpha Centauri is just 30 degrees from the south celestial pole. As a result, the radiant essentially never sets for observers across Australia. The best rates will be seen from late evening onward, as the radiant rises higher into the southern sky. </p>
<p>This year, the peak of the Alpha Centaurids coincides with the New Moon, making it an ideal time to check out this minor but fascinating shower.</p>
<h2><a id="term-eta-aquariids"></a>Eta Aquariids [S preferred]</h2>
<h3>Active: April 19 - May 28</h3>
<h3>Maximum: May 6, 2pm UT = May 6, 10pm (WA) = May 7, 12am (Qld/NSW/ACT/Vic/Tas)</h3>
<h3>ZHR = 40+</h3>
<h3>Parent: <a href="http://cometography.com/pcomets/001p.html">Comet 1P/Halley</a></h3>
<p>The Eta Aquariids are possibly the year’s most overlooked treat, particularly for observers in the southern hemisphere. The first of two annual showers produced by comet <a href="http://cometography.com/pcomets/001p.html">1P/Halley</a>, the Eta Aquariids produce excellent rates for a whole week around their peak.</p>
<p>The radiant rises in the early hours of the morning, after the forecast maximum time, and best rates are seen just as the sky starts to brighten with the light of dawn. It can be well worth rising early to observe them, as rates can climb as high as 40 to 50 meteors per hour before the brightening sky truncates the display.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/250844/original/file-20181217-185255-1azxn7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/250844/original/file-20181217-185255-1azxn7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/250844/original/file-20181217-185255-1azxn7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=566&fit=crop&dpr=1 600w, https://images.theconversation.com/files/250844/original/file-20181217-185255-1azxn7j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=566&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/250844/original/file-20181217-185255-1azxn7j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=566&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/250844/original/file-20181217-185255-1azxn7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=712&fit=crop&dpr=1 754w, https://images.theconversation.com/files/250844/original/file-20181217-185255-1azxn7j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=712&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/250844/original/file-20181217-185255-1azxn7j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=712&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Look for the Eta Aquariids before sunrise and catch Venus and Mercury too.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Eta Aquariid meteors are fast and often bright, and the shower regularly rewards those who are willing to rise early. Spectacular Earth-grazing meteors that tear from one side of the sky to the other can be seen shortly after the radiant rises above the horizon.</p>
<p>This year conditions are ideal to observe the shower, with New Moon falling on May 4, just two days before the forecast maximum. As a result, the whole week around the peak will be suitable for morning observing sessions, giving observers plenty of opportunity to see the fall of tiny fragments of the most famous of comets.</p>
<h2><a id="term-southern-delta-aquariids"></a>Southern Delta Aquariids, <a id="term-piscis-austrinids"></a>Piscis Austrinids and <a id="term-alpha-capricornids"></a>Alpha Capricornids [N/S; S favoured]</h2>
<h3>Active: Early-July to Mid-August</h3>
<h3>Maximum: July 28 - 30</h3>
<h3>Combined ZHR: 35</h3>
<h3>Parent: Comet <a href="http://cometography.com/pcomets/096p.html">96P/Macholz</a> (Southern Delta Aquariids); Unknown (Piscis Austrinids); Comet <a href="https://authors.library.caltech.edu/86156/1/1-s2.0-S0032063317304518-main.pdf">169P/NEAT</a> (Alpha Capricornids)</h3>
<p>In most years, the approach of August is heralded by keen meteor observers as the build up to the Perseids – the second of the year’s big three showers. This year, moonlight will interfere, spoiling them for most observers.</p>
<p>But this cloud comes with a silver lining. A fortnight or so before the peak of the Perseids, three relatively minor showers come together to provide an excellent mid-winter show for southern hemisphere observers. This year, the Moon is perfectly placed to allow their observation.</p>
<p>These three showers – the Southern Delta Aquariids, Alpha Capricornids and Pisces Austrinids – favour observers in the southern hemisphere, though they can also be observed from northern latitudes. </p>
<p>Regardless of your location, the best rates for these showers are seen in the hours after midnight. Reasonable rates begin to be visible for southern hemisphere observers as early as 10pm local time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/249571/original/file-20181210-72504-109hsrj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/249571/original/file-20181210-72504-109hsrj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249571/original/file-20181210-72504-109hsrj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=533&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249571/original/file-20181210-72504-109hsrj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=533&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249571/original/file-20181210-72504-109hsrj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=533&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249571/original/file-20181210-72504-109hsrj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=670&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249571/original/file-20181210-72504-109hsrj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=670&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249571/original/file-20181210-72504-109hsrj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=670&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The radiants of the Southern Delta Aquariids, Alpha Capricornids and Piscis Austrinids ride high in the southern hemisphere sky around local midnight.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/249573/original/file-20181210-72536-1muhwdq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/249573/original/file-20181210-72536-1muhwdq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249573/original/file-20181210-72536-1muhwdq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=513&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249573/original/file-20181210-72536-1muhwdq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=513&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249573/original/file-20181210-72536-1muhwdq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=513&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249573/original/file-20181210-72536-1muhwdq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=645&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249573/original/file-20181210-72536-1muhwdq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=645&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249573/original/file-20181210-72536-1muhwdq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=645&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For northern hemisphere observers, the radiants of the same three showers sit low to the horizon around local midnight.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>The Southern Delta Aquariids are the most active of the three, producing up to 25 fast, bright meteors per hour at their peak, which spans the five days centred on July 30.</p>
<p>The Alpha Capricornids, by contrast, produce lower rates typically contributing just five meteors per hour. But where the Southern Delta Aquariids are fast, the Alpha Capricornids are very slow meteors and are often spectacular. </p>
<p>Like the Alpha Centaurids, in February, they have a reputation for producing large numbers of spectacular fireballs. This tendency to produce meteors that are both very bright and also slow moving makes them an excellent target for astrophotographers, as well as naked-eye observers.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/251140/original/file-20181218-27767-1yffjjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/251140/original/file-20181218-27767-1yffjjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/251140/original/file-20181218-27767-1yffjjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/251140/original/file-20181218-27767-1yffjjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/251140/original/file-20181218-27767-1yffjjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/251140/original/file-20181218-27767-1yffjjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/251140/original/file-20181218-27767-1yffjjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/251140/original/file-20181218-27767-1yffjjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An Alpha Capricornid meteor captured among the star trails in 2013.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/jeffreysullivan/21986263774/">Flickr/Jeff Sullivan</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2><a id="term-taurids"></a>Taurids [N/S]</h2>
<h3>Active: September 10 - December 10</h3>
<h3>Maxima: October 10 (Southern Taurids); November 13 (Northern Taurids)</h3>
<h3>ZHR: 5 + 5</h3>
<h3>Parent: <a href="http://cometography.com/pcomets/002p.html">Comet 2P/Encke</a></h3>
<p>The Taurids are probably the most fascinating of all the annual meteor showers. Though they only deliver relatively low rates (approximately five per hour from each of the two streams, north and south), they do so over an incredibly long period – three full months of activity. </p>
<p>In other words, the Earth spends a quarter of a year passing through the Taurid stream. In fact, we cross the stream again in June, when the meteors from the shower are lost due to it being exclusively visible in daylight. </p>
<p>So a third of our planet’s orbit is spent ploughing through a broad stream of debris, known as the Taurid stream. In total, the Taurid stream deposits more mass of meteoric material to our planet’s atmosphere than all of the other annual meteor showers combined.</p>
<p>So vast is the Taurid stream that there is speculation that it originated with the <a href="https://doi.org/10.1093/mnras/251.4.632">cataclysmic disintegration of a super-sized comet</a>, thousands or tens of thousands of years in the past, and that the current shower is a relic of that ancient event. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/249578/original/file-20181210-76986-1letx58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/249578/original/file-20181210-76986-1letx58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249578/original/file-20181210-76986-1letx58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=523&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249578/original/file-20181210-76986-1letx58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=523&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249578/original/file-20181210-76986-1letx58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=523&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249578/original/file-20181210-76986-1letx58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=657&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249578/original/file-20181210-76986-1letx58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=657&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249578/original/file-20181210-76986-1letx58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=657&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The two Taurid radiants, as seen from northern Europe before dawn [Paris 6:30am, October 10]</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/250918/original/file-20181217-185237-1nzz6tc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/250918/original/file-20181217-185237-1nzz6tc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/250918/original/file-20181217-185237-1nzz6tc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=433&fit=crop&dpr=1 600w, https://images.theconversation.com/files/250918/original/file-20181217-185237-1nzz6tc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=433&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/250918/original/file-20181217-185237-1nzz6tc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=433&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/250918/original/file-20181217-185237-1nzz6tc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=544&fit=crop&dpr=1 754w, https://images.theconversation.com/files/250918/original/file-20181217-185237-1nzz6tc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=544&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/250918/original/file-20181217-185237-1nzz6tc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=544&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The November maximum will be hindered by the Moon, this view as seen from Melbourne during the early hours of November 13.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Taurid meteors are slow, and are often spectacularly bright. Like the Alpha Capricornids, they have a reputation for producing regular fireballs, making them another good target for the budding astrophotographer. </p>
<p>Rather than having a single, sharp peak, Taurid activity stays at, or close to, peak rates for the best part of a month, between the maxima of the northern and southern streams, meaning that it is always possible to find some time when moonlight does not interfere to observe the shower. </p>
<h2><a id="term-geminids"></a>Geminids [N/S]</h2>
<h3>Active: December 4 - December 17</h3>
<h3>Maximum: December 14, 6:40pm UT = December 15, 4:40am (Qld) = December 15, 5:40am (NSW/ACT/Vic/Tas)</h3>
<h3>ZHR: 140+</h3>
<h3>Parent: Asteroid <a href="https://echo.jpl.nasa.gov/asteroids/Phaethon/Phaethon_planning.2017.html">3200 Phaethon</a></h3>
<p>Another of the big three annual meteor showers, the Geminids are probably the best, with peak rates in recent years exceeding 140 meteors per hour.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/251106/original/file-20181217-185268-1wqem63.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/251106/original/file-20181217-185268-1wqem63.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/251106/original/file-20181217-185268-1wqem63.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/251106/original/file-20181217-185268-1wqem63.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/251106/original/file-20181217-185268-1wqem63.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/251106/original/file-20181217-185268-1wqem63.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/251106/original/file-20181217-185268-1wqem63.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/251106/original/file-20181217-185268-1wqem63.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A composite image of the Geminids shower from the vantage point of Johnson Space Center, US.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nasamarshall/46288430991/">NASA/Lauren Harnett</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>The Geminids are visible from both hemispheres – although the radiant rises markedly earlier for northern observers. Even in the south of Australia, the radiant rises well before midnight, giving all observers the rest of the night to enjoy the spectacle.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/250916/original/file-20181217-185249-wj9zwx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/250916/original/file-20181217-185249-wj9zwx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/250916/original/file-20181217-185249-wj9zwx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=516&fit=crop&dpr=1 600w, https://images.theconversation.com/files/250916/original/file-20181217-185249-wj9zwx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=516&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/250916/original/file-20181217-185249-wj9zwx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=516&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/250916/original/file-20181217-185249-wj9zwx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=648&fit=crop&dpr=1 754w, https://images.theconversation.com/files/250916/original/file-20181217-185249-wj9zwx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=648&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/250916/original/file-20181217-185249-wj9zwx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=648&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Moon interferes with the Geminids, which radiate close to the bright star Castor. This view is from Perth in the hours before sunrise.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Moonlight will seriously interfere with the peak of the shower this year, washing out the fainter meteors, with the result that observed rates will be lower than the ZHR might otherwise suggest. </p>
<p>But the shower regularly produces abundant bright meteors, and yields such high rates that it is still well worth checking out, even through the glare of the full Moon. </p>
<h2><a id="term-ursids"></a>Ursids [N]</h2>
<h3>Active: December 17 - December 26</h3>
<h3>Maximum: December 23, 3:00am UT</h3>
<h3>ZHR: 10+</h3>
<h3>Parent: <a href="http://cometography.com/pcomets/008p.html">Comet 8P/Tuttle</a></h3>
<p>The final shower of the year – the Ursids – is a treat for northern hemisphere observers alone. Much like the shower that started our journey through the year, the Quadrantids, the Ursids remain poorly observed, often lost to the bleak midwinter weather that plagues many northern latitudes.</p>
<p>But if skies are clear the Ursids are visible throughout the night, as their radiant lies just 12 degrees from the north celestial pole. As such, they make a tempting target for observers to check out in the evening, even if the radiant is at its highest in the early hours of the morning.</p>
<p>Most years, the Ursids are a relatively minor shower, with peak rates rarely exceeding ten meteors per hour. They have thrown up a few surprises over the past century, with occasional outbursts of moderately-fast meteors yielding rates up to, and in excess of, a hundred meteors per hour.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/249577/original/file-20181210-76971-1drjl8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/249577/original/file-20181210-76971-1drjl8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249577/original/file-20181210-76971-1drjl8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=516&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249577/original/file-20181210-76971-1drjl8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=516&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249577/original/file-20181210-76971-1drjl8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=516&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249577/original/file-20181210-76971-1drjl8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=648&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249577/original/file-20181210-76971-1drjl8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=648&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249577/original/file-20181210-76971-1drjl8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=648&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Ursid radiant, in the constellation Ursa Minor, is circumpolar for almost the entire northern hemisphere, as it lies just 12 degrees from the north celestial pole. It is shown here as it would be seen at 11pm from near Tokyo, Japan.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>While no such outburst is predicted for 2019, the Ursids have proven to be a shower with a surprise or two left to show and so may just prove to be an exciting way to end the meteoric year.</p>
<hr>
<p><em>If you have a good photo of any of this year’s meteor showers that you’d like to share with The Conversation’s readers then please send it to <a href="mailto:readerspic@theconversation.edu.au">readerspic@theconversation.edu.au</a>. Please include your full name and the location the photo (or any composite) was taken.</em></p><img src="https://counter.theconversation.com/content/106863/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Moonlight will spoil some of the big meteor showers this year, but still plenty of others to see. So here’s your guide on when and where to look to catch nature’s fireworks.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandTanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1085052018-12-11T10:28:28Z2018-12-11T10:28:28ZGeminids meteor shower: an astrophysicist on what to look out for<figure><img src="https://images.theconversation.com/files/249622/original/file-20181210-76986-cdg5pt.jpg?ixlib=rb-1.1.0&rect=123%2C23%2C5036%2C3311&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A spectacular display.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/geminid-meteors-shower-downward-this-composite-1175362177?src=IaiaWHx2ctulFFkGuHS_iA-1-22">Shutterstock.</a></span></figcaption></figure><p>The Geminids meteor shower peaks on the mornings of December 13 and 14, 2018 – but if you <a href="https://theconversation.com/look-up-your-guide-to-some-of-the-best-meteor-showers-for-2018-86053">look up</a> any time there’s a clear night sky up until December 17, you might just catch a glimpse of a Geminid meteor. </p>
<p>The <a href="http://iopscience.iop.org/article/10.1088/0004-6256/140/5/1519/meta">Geminids shower is unusual</a> as it is one of two meteor showersconfirmed to be caused by an asteroid (most meteor showers are caused by comets). The Earth passes through the debris cloud scattered by an asteroid called 3200 Phaethon in December each year. The fiery display is caused as the debris is vapourised by the Earth’s atmosphere, having travelled through the solar system for <a href="https://www.nature.com/articles/ngeo941">4.6 billion years</a>. </p>
<p>The <a href="https://www.imo.net/resources/calendar/">Geminids</a> shower is noted for producing 120 or more meteors per hour, which travel at around 35 kilometres per second, and are often brightly coloured. The colours indicate <a href="https://leonid.arc.nasa.gov/meteor.html">the main chemical composition</a> of that particular meteor. An orange or yellow colour denotes sodium, yellow signifies iron, blue-green means magnesium and violet indicates calcium. If the meteor appears red, that’s nitrogen and oxygen atoms in the atmosphere glowing as they are super heated by the space dust slamming into them at high speed.</p>
<h2>About that asteroid</h2>
<p>3200 Phaethon has a wildly eccentric orbit, quite different to many other asteroids. At its furthest point from the centre of the solar system, 3200 Phaethon enters the asteroid belt between the orbits of Mars and Jupiter, around 360m kilometres from the Sun (for context, Earth is around 150m kilometres from the Sun). At its closest point, it’s 21m kilometres away – a mere stone’s throw from the Sun, in astronomical terms. Here, the asteroid can bake in temperatures up to 750°C. </p>
<p>3200 Phaethon is a measly 5.8 kilometres long. It crosses the orbit of the Earth, so it’s classed as a near Earth object (NEO). But it’s unlikely to ever hit the Earth: the <a href="https://newton.spacedys.com/neodys/index.php?pc=1.1.8&n=3200">next nearest approach is not until 2093</a>, at a distance almost eight times further away than the moon. Beyond 2093, if it did hit us, it would cause significant damage, but it probably wouldn’t cause an extinction-level event. The asteroid or comet that helped to wipe out the dinosaurs is estimated to have been <a href="https://link.springer.com/article/10.1007/s11208-005-0051-0">ten to 15 kilometres long</a>. </p>
<figure>
<iframe src="https://player.vimeo.com/video/305617790" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
</figure>
<p>The extreme variations in temperature experienced by 3200 Phaethon, together with a very short day of just 3.6 hours and regular close encounters with the Sun causes the asteroid to shed dust and debris at a rate great enough that <a href="http://iopscience.iop.org/article/10.1088/2041-8205/771/2/L36/meta">dust tails have been observed</a>. This, and other observations, have led some astronomers to describe this object as a comet or a “rock comet”, somewhat blurring the line between asteroids and comets. </p>
<p>Indeed, scientist are only just beginning to understand the distinction between <a href="https://theconversation.com/looks-like-a-comet-but-feels-like-an-asteroid-thats-wild-20268">comets and asteroids</a>. In the past, scientists thought of comets as interlopers from the far outskirts of the solar system, which were somehow disturbed and dragged inwards by the gravity of the Sun. </p>
<p>Asteroids, on the other hand, were thought to have formed alongside the planets, ending up on the boundary of the inner and outer solar system. They mostly reside in the asteroid belt – altogether, their total mass is no more than <a href="https://doi.org/10.1006/icar.2002.6837">around 4% of the moon</a>. While 3200 Phaethon is often referred to as an asteroid, it seems the more we learn, the less relevant the distinction between the terms asteroid and comet really is. </p>
<p>Technically, these terms are already obsolete, because <a href="https://www.iau.org/news/pressreleases/detail/iau0603/">in 2006</a>, when the International Astronomical Union (IAU) reclassified Pluto as a dwarf planet, it also decided that “all other objects, except satellites, orbiting the Sun shall be referred to collectively as small solar-system bodies”. This essentially removes the need for words like asteroid and comet, but of course they persist in the scientific and public vocabulary.</p>
<h2>Become a citizen scientist</h2>
<p>Meteors are best observed in a dark location with a clear view of the sky – a backyard or local park, or even better, the countryside. It’s worth staying for at least an hour, to increase your chances of spotting one. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/249835/original/file-20181210-76965-16jd6t3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249835/original/file-20181210-76965-16jd6t3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249835/original/file-20181210-76965-16jd6t3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249835/original/file-20181210-76965-16jd6t3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249835/original/file-20181210-76965-16jd6t3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249835/original/file-20181210-76965-16jd6t3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249835/original/file-20181210-76965-16jd6t3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A fireball, captured at Bayfordbury Observatory.</span>
<span class="attribution"><a class="source" href="http://star.herts.ac.uk/allsky/index.php">Bayfordbury AllSky Camera/University of Hertfordshire.</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Any time you are sky watching, if you happen to see a huge, bright meteor that lasts for several seconds – known as a fireball – you can <a href="https://ukmeteornetwork.co.uk/fireball-report/">report it to scientists</a> so that they can follow up. If the piece of rock that caused the fireball was large enough, some of it could make it to the ground, becoming a meteorite. For every report that is submitted, the easier it will be to possibly find some left over space rock to study.</p>
<p>Make a note of the time you saw the fireball, the direction it travelled and any other relevant information. If you happen to capture a photo or a video, even better. These reports are really valuable as they help scientists in various fields: it could help astronomers identify unknown NEOs, and help geologists and planetary scientists to learn more about the formation of our solar system.</p><img src="https://counter.theconversation.com/content/108505/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samantha Rolfe does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Expect a spectacular display of 120 or more meteors per hour – some of them brightly coloured.Samantha Rolfe, Lecturer in Astrobiology and Principal Technical Officer at Bayfordbury Observatory, University of HertfordshireLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1009822018-08-07T13:06:42Z2018-08-07T13:06:42ZHow ancient cultures explained comets and meteors<figure><img src="https://images.theconversation.com/files/230771/original/file-20180806-34489-1u9mavr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/scientific-background-bright-comet-dark-blue-238563268?src=yNSHHz2wUzFpegKdoINhlQ-1-15">IgorZh/Shutterstock</a></span></figcaption></figure><p>Comets and meteors have fascinated the human race since they were first spotted in the night sky. But without science and space exploration to aid understanding of what these <a href="https://www.universetoday.com/100075/infographic-whats-the-difference-between-a-comet-asteroid-and-meteor/">chunks of rock and ice are</a>, ancient cultures often turned to myth and legend to explain them.</p>
<p>The <a href="http://journals.sagepub.com/doi/abs/10.1177/002182860703800203">Greeks and Romans believed</a> that the appearance of comets, meteors and meteor showers were portentous. They were signs that something good or bad had happened or was about to happen. The arrival of a comet could herald the birth of a great figure, and some people have even argued that the star in the sky which the Persian Magi followed to Bethlehem to see the newborn Jesus <a href="https://theconversation.com/what-can-science-tell-us-about-the-star-of-bethlehem-51773">was actually a comet</a>. </p>
<p>In the spring of 44BC, a comet that appeared was interpreted as <a href="http://www.bbc.co.uk/religion/0/20786572">a sign of the deification</a> of Julius Caesar, <a href="https://www.ancient.eu/article/803/the-murder-of-julius-caesar/">following his murder</a>. Caesar’s adopted son Octavian (soon to be the Emperor Augustus) made much of the comet, which burned in the sky during the funerary games held for Caesar. This portentous event was frequently celebrated in the ancient sources. In his epic poem, the Aeneid, Virgil <a href="http://www.gutenberg.org/files/228/228-h/228-h.htm#link2HCH0006">describes how</a> “a star appeared in the daytime, and Augustus persuaded people to believe it was Caesar”.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/230782/original/file-20180806-191019-vbe9q1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/230782/original/file-20180806-191019-vbe9q1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/230782/original/file-20180806-191019-vbe9q1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=294&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230782/original/file-20180806-191019-vbe9q1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=294&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230782/original/file-20180806-191019-vbe9q1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=294&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230782/original/file-20180806-191019-vbe9q1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=369&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230782/original/file-20180806-191019-vbe9q1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=369&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230782/original/file-20180806-191019-vbe9q1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=369&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Caesar’s comet, depicted on a denarius coin.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:S0484.4.jpg">Wikimedia/Classical Numismatic Group, Inc.</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Augustus celebrated the comet and the deification of his father on coins (it did help to be the son of a god when trying to rule the Roman Empire), and many examples survive today. </p>
<h2>Meteor showers</h2>
<p>The Roman historian Cassius Dio referred to “<a href="https://books.google.co.uk/books?id=cm6PBAAAQBAJ&pg=RA1-PR110&lpg=RA1-PR110&dq=cassius+dio+%22comet+stars%22&source=bl&ots=CFyYIEOB-6&sig=jto_KSWb_F8uuypw98O-Awfu_QM&hl=en&sa=X&ved=2ahUKEwj08sD5lNjcAhUUVsAKHRv6BgMQ6AEwAXoECAkQAQ#v=onepage&q=cassius%20dio%20%22comet%20stars%22&f=false">comet stars</a>” occurring in August 30BC. These are mentioned as among the portents witnessed <a href="http://adsabs.harvard.edu/full/1978JRASC..72...81B">after the death of the Egyptian queen Cleopatra</a>. Experts are not entirely sure what it means when Dio uses the plural term “comet stars”, but some have connected this recorded event to the annual Perseid meteor shower.</p>
<p>Though it retains an ancient Greek name, <a href="https://theconversation.com/explainer-why-the-august-night-sky-lights-up-with-the-perseid-meteor-shower-63794">we now know</a> that the arrival of the Perseid meteor shower every August is actually the Earth’s orbit passing through debris from the Swift-Tuttle comet.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/230781/original/file-20180806-191044-vjvsho.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/230781/original/file-20180806-191044-vjvsho.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/230781/original/file-20180806-191044-vjvsho.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=671&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230781/original/file-20180806-191044-vjvsho.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=671&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230781/original/file-20180806-191044-vjvsho.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=671&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230781/original/file-20180806-191044-vjvsho.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=843&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230781/original/file-20180806-191044-vjvsho.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=843&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230781/original/file-20180806-191044-vjvsho.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=843&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Perseus flees after cutting off Medusa’s head in this water jar depiction.</span>
<span class="attribution"><a class="source" href="http://www.britishmuseum.org/research/collection_online/collection_object_details/collection_image_gallery.aspx?partid=1&assetid=980386001&objectid=461872">British Museum</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>The meteor shower is named for the Perseidai (Περσείδαι), who were the sons of the ancient Greek hero Perseus. Perseus was a legendary figure with a fine family pedigree – he was the mythical son of Zeus and Argive princess Danaë (she of the golden rain). Perseus <a href="http://earthsky.org/constellations/cassiopeia-and-perseus-in-northeast-on-october-evenings">earned himself a constellation</a> after a number of epic adventures across the Mediterranean and Near East that included the frequently illustrated <a href="https://www.ancient.eu/Medusa/">murder of the Gorgon sister, Medusa</a>.</p>
<p>Another of Perseus’s celebrated acts was <a href="https://www.poetryintranslation.com/PITBR/Latin/Metamorph4.php#anchor_Toc64106270">the rescue of the princess Andromeda</a>. Abandoned by her parents to placate a sea monster, the princess was found by Perseus on a rock by the ocean. He married her and they went on to have seven sons and two daughters. Sky watchers believed that the constellation Perseus, located just beside Andromeda in the night sky, was the origin of the shooting stars they could see every summer, and so the name Perseid stuck. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/230789/original/file-20180806-191022-c0ioa3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/230789/original/file-20180806-191022-c0ioa3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/230789/original/file-20180806-191022-c0ioa3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=711&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230789/original/file-20180806-191022-c0ioa3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=711&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230789/original/file-20180806-191022-c0ioa3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=711&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230789/original/file-20180806-191022-c0ioa3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=893&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230789/original/file-20180806-191022-c0ioa3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=893&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230789/original/file-20180806-191022-c0ioa3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=893&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wall painting from Pompeii, representing Perseus rescuing Andromeda.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Museo_Nazionale_Napoli_Perseus_And_Andromeda.jpg">Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Tears and other traditions</h2>
<p>In Christian tradition the Perseid meteor shower has long been <a href="https://www.catholicnewsagency.com/news/in-august-watch-this-meteor-shower-named-for-a-saint-62501">connected to the martyrdom of St Lawrence</a>. Laurentius was a deacon in the early church at Rome, martyred in the year 258AD, during the <a href="https://books.google.co.uk/books?id=1SOQBAAAQBAJ&printsec=frontcover&source=gbs_ge_summary_r&redir_esc=y#v=onepage&q&f=false">persecutions of the Emperor Valerian</a>. The martyrdom supposedly took place on August 10, when the meteor shower was at its height, and so the shooting stars are equated to the saint’s tears. </p>
<p>Detailed records of astronomical events and sky watching can be found in historical texts from the Far East too. Ancient and medieval records from <a href="https://www.sciencedirect.com/science/article/pii/0146636477900019">China</a>, <a href="http://cds.cern.ch/record/815141/files/0501216.pdf">Korea</a> and Japan have all been found to contain detailed accounts of meteor showers. Sometimes these different sources <a href="http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1958SCoA....2..131I&classic=YES">can be correlated</a>, which has allowed astronomers to track, for example, the impact of Halley’s comet on ancient societies both east and west. These sources have also been used to find the <a href="http://adsbit.harvard.edu//full/1958SCoA....2..131I/0000139.000.html">first recorded observation</a> of the Perseid meteor shower as a specific event, in Han Chinese records of 36AD.</p>
<p>Though the myths and legends may make one think that ancient civilisations had little scientific understanding of what meteors, comets and asteroids could be, this couldn’t be farther from the truth. The early astronomers of the Near East, those who created the <a href="https://www.staff.science.uu.nl/%7Egent0113/babylon/babycal.htm">Babylonian</a> and <a href="https://www.jstor.org/stable/985113">Egyptian calendars</a>, and astronomical data were – by far – the most advanced in antiquity. And a <a href="https://news.nationalgeographic.com/2016/01/160128-math-geometry-babylon-jupiter-astronomy-space/">recent study of ancient cuneiform texts</a> has proven that the Babylonian ability to track comets, planetary movements and sky events as far back as the first millennium BC involved a much more complex geometry than had been previously believed.</p><img src="https://counter.theconversation.com/content/100982/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eve MacDonald does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Without the scientific knowledge we have today, ancient cultures turned to myths and legends to understand celestial objects.Eve MacDonald, Lecturer in Ancient History, Cardiff UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/979752018-06-28T11:01:48Z2018-06-28T11:01:48ZNew telescope will scan the skies for asteroids on collision course with Earth<figure><img src="https://images.theconversation.com/files/224506/original/file-20180622-26558-f8q147.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist depiction of an asteroid on a collision course with Earth</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/large-asteroid-closing-on-earth-95167171?src=to8AFSoMLoWFaKqU7UeLig-1-41">By Mopic/shutterstock.com</a></span></figcaption></figure><p>Around sunrise on Feb. 15, 2013, an extremely bright and otherworldly object was seen streaking through the skies over Russia before it exploded about 97,000 feet above the Earth’s surface. The resulting blast damaged thousands of buildings and injured almost 1,500 people in Chelyabinsk and the surrounding areas. While this sounds like the first scene of a science fiction movie, this invader wasn’t an alien spaceship attacking humanity, but a <a href="http://doi.org/10.1126/science.1242642">20-meter-wide asteroid that had collided with the Earth</a>. </p>
<p>What is worrisome is that no one had any idea this 20-meter asteroid existed until it entered the Earth’s atmosphere that morning.</p>
<p>As an astronomer, I study objects in the sky that change in brightness over short time scales – observations that I use to detect planets around other stars. A large part of my research is understanding how we can better design and run telescopes to monitor an ever-changing sky. That’s important because the same telescopes I’m using to explore other star systems are also being designed to help my colleagues discover objects in our own solar system, like asteroids on a collision course with with Earth.</p>
<h2>Near-Earth objects</h2>
<p>A meteor is any chunk of matter that enters the Earth’s atmosphere. Before the Chelyabinsk meteor met its demise on Earth, it was orbiting our sun as an asteroid. These rocky objects are normally thought to be restricted to the asteroid belt between Mars and Jupiter. However, there are many asteroids throughout the solar system. Some, like the Chelyabinsk meteor, are known as near-Earth objects (NEOs). </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/224509/original/file-20180622-26567-1nep0we.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/224509/original/file-20180622-26567-1nep0we.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/224509/original/file-20180622-26567-1nep0we.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/224509/original/file-20180622-26567-1nep0we.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/224509/original/file-20180622-26567-1nep0we.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/224509/original/file-20180622-26567-1nep0we.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/224509/original/file-20180622-26567-1nep0we.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/224509/original/file-20180622-26567-1nep0we.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aerial view of Arizona Meteor Crater, September 2010.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Meteor_Crater#/media/File:Meteorcrater.jpg">Shane Torgerson</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The Chelyabinsk meteor likely came from a group of NEOs called Apollo asteroids, named after the asteroid 1862 Apollo. There are more than 1,600 known Apollo asteroids logged in the <a href="https://ssd.jpl.nasa.gov/sbdb.cgi">JPL Small-Body Database</a> that have orbits that may cross the Earth’s path, and are large enough (over 140 meters), that they’re considered potentially hazardous asteroids (PHAs) because a collision with Earth would devastate the region hit. </p>
<p>The scars of these past collisions are prominent on the moon, but the Earth also bears the marks of such impacts. <a href="http://www.passc.net/EarthImpactDatabase/chicxulub.html">Chicxulub crater</a> on Mexico’s Yucatan Peninsula was created by the Chicxulub asteroid that drove the dinosaurs to extinction. The <a href="http://www.passc.net/EarthImpactDatabase/barringer.html">Barringer Crater in Arizona is just 50,000 years old</a>. The question is not if a dangerously large asteroid will collide with the Earth, but when?</p>
<h2>Searching for threats</h2>
<p>The U.S. government is taking the threat of an asteroid collision seriously. In Section 321 of the <a href="https://www.congress.gov/bill/109th-congress/senate-bill/1281/text?overview=closed">NASA Authorization Act of 2005</a>, Congress required NASA develop a program to search for NEOs. NASA was assigned the task of identifying 90 percent of all NEOs greater than 140 meters in diameter. Currently, they estimate that <a href="https://www.nasa.gov/planetarydefense/faq">three-quarters of the 25,000 PHAs have yet to be found</a>. </p>
<p>To reach this goal, an international team of of hundreds of scientists, including myself, is completing construction of the Large Synoptic Survey Telescope (LSST) in Chile, which will be an essential tool for alerting us of PHAs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/224507/original/file-20180622-26564-uvawfp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/224507/original/file-20180622-26564-uvawfp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/224507/original/file-20180622-26564-uvawfp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/224507/original/file-20180622-26564-uvawfp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/224507/original/file-20180622-26564-uvawfp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/224507/original/file-20180622-26564-uvawfp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/224507/original/file-20180622-26564-uvawfp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/224507/original/file-20180622-26564-uvawfp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Exterior view of the Large Synoptic Survey Telescope, which is still under construction.
Sublocation Cerro Pachón, Chile.</span>
<span class="attribution"><a class="source" href="https://gallery.lsst.org/bp/#/folder/3989372/71658815">LSST Project/NSF/AURA</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>With significant funding from the U.S. National Science Foundation, LSST will search for PHAs during its 10-year mission by observing the same area of sky at hourly intervals searching for objects that have changed position. Anything that moves in just one hour has to be so close that it is within our solar system. Teams led by researchers at the <a href="https://arxiv.org/pdf/1711.10621.pdf">University of Washington</a> and <a href="https://arxiv.org/pdf/1706.09398.pdf">JPL</a> have both produced simulations showing that LSST on its own will be capable of finding around 65 percent of PHAs. If we combine LSST data with other astronomical surveys like <a href="http://pswww.ifa.hawaii.edu/pswww/">Pan-STARRS</a> and the <a href="https://catalina.lpl.arizona.edu/">Catalina Sky Survey</a>, we think we can help reach that goal of discovering 90 percent of potentially hazardous asteroids.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/224508/original/file-20180622-26573-hlszro.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/224508/original/file-20180622-26573-hlszro.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/224508/original/file-20180622-26573-hlszro.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/224508/original/file-20180622-26573-hlszro.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/224508/original/file-20180622-26573-hlszro.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=567&fit=crop&dpr=1 754w, https://images.theconversation.com/files/224508/original/file-20180622-26573-hlszro.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=567&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/224508/original/file-20180622-26573-hlszro.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=567&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A photograph and a baseline design rendering mix, showing a view of the completed exterior building from the road leading up to the site.</span>
<span class="attribution"><a class="source" href="https://gallery.lsst.org/bp/#/search/51636894?q=telescope&folderId=2334407&folderName=Facility&filters=%257B%2522date_created_unix%2522%253A%257B%2522from%2522%253A%252201%252F01%252F2018%2522%252C%2522to%2522%253A%252206%252F30%252F2018%2522%257D%257D">LSST Project/NSF/AURA</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Preparing to avert disaster</h2>
<p>Both the Earth and these asteroids are orbiting the sun, just on different paths. The more observations taken of a given asteroid, the more precisely its orbit can be mapped and predicted. The biggest priority, then, is finding asteroids that may collide with the Earth in the future. </p>
<p>If an asteroid is on a collision course hours or days before it occurs, the Earth won’t have many options. It’s like a car suddenly pulling out in front of you. There is little that you can do. If, however, we find these asteroids years or decades before a potential collision, then we may be able to use spacecraft to nudge the asteroid enough to change its path so that it and the Earth don’t collide.</p>
<p>This is, however, easier said than done, and currently, no one really knows how well an asteroid can be redirected. There have been several proposals for <a href="https://www.nasa.gov/planetarydefense/dart">missions by NASA</a> and the <a href="https://www.esa.int/Our_Activities/Space_Engineering_Technology/Hera/Asteroid_Impact_Mission2">European Space Agency to do this</a>, but so far, they have not passed early stages of mission development. </p>
<p>The <a href="http://www.b612foundation.org/">B612 Foundation</a>, a private nonprofit group, is also trying to privately raise money for a mission to redirect an asteroid, and they may be the first to attempt this if the government space programs don’t. Pushing an asteroid sounds like an odd thing to do, but when we one day find an asteroid on a collision course with Earth, it may well be that knowledge that will save humanity.</p><img src="https://counter.theconversation.com/content/97975/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael B. Lund is affiliated with one of the science collaborations for the Large Synoptic Survey Telescope.</span></em></p>An asteroid on a collision course with Earth is inevitable. Astronomer Michael Lund explains how a new telescope under construction in Chile will become a vital tool for detecting objects that could devastate our planet.Michael B. Lund, Post-doctoral researcher, Department of Physics & Astronomy, Vanderbilt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/914682018-02-15T16:08:48Z2018-02-15T16:08:48Z‘Black Panther’ roars. Are we listening?<figure><img src="https://images.theconversation.com/files/206499/original/file-20180215-124886-18xcxrs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Letitia Wright in _Black Panther_. Popular discussions about the movie demonstrate a desire for representation in commercial media. </span> <span class="attribution"><span class="source">(Marvel/Disney)</span></span></figcaption></figure><p>Marvel Studios’ <em>Black Panther</em>, opening tonight in theatres across Canada and the United States, is pretty much guaranteed to be a hit. It <a href="http://deadline.com/2018/01/black-panther-advance-ticket-sales-record-fandango-superhero-movies-1202275304/">set records for advance ticket sales on Fandango</a>, its <a href="https://www.billboard.com/articles/columns/chart-beat/8099442/black-panther-soundtrack-number-1-debut-billboard-200">soundtrack album debuted in the No. 1 spot on the Billboard charts</a> and <a href="https://www.washingtonpost.com/amphtml/news/comic-riffs/wp/2018/02/13/black-panther-is-now-on-track-to-be-the-biggest-february-opening-ever/">industry estimates point to opening-weekend revenues as high as US$170 million</a>. </p>
<p>Director Ryan Coogler and star Chadwick Boseman appeared on the cover of the industry trade magazine <a href="http://variety.com/2018/film/features/black-panther-chadwick-boseman-ryan-coogler-interview-1202686402"><em>Variety</em></a>, while <a href="http://www.gq-magazine.co.uk/article/black-panther-michael-b-jordan-cover"><em>British GQ</em></a> styled actor Michael B. Jordan to recall Black Panther Party activists. The red-carpet premiere <a href="https://theconversation.com/black-panther-honouring-the-legacy-of-black-style-91067">made a splash on celebrity and fashion blogs</a>, and it’s <a href="http://variety.com/2018/digital/news/black-panther-twitter-record-2018-1202695436/">the most-tweeted-about film of the year</a>. Marvel’s had big hits before. But this feels like something different.</p>
<h2>Ahead of its time</h2>
<p>The Black Panther, also known as King T’Challa of Wakanda, <a href="https://www.britannica.com/topic/Black-Panther-comic-book-character">was created as a comic book hereo in 1966</a> by artist Jack Kirby and writer/editor Stan Lee. Although considered the first Black superhero in American comics, this is not the first time we’ve seen a Black superhero in the cinema. Comedian Robert Townsend gave us Meteor Man in 1993, Shaquille O’Neal portrayed the DC Comics character Steel in 1997 and Wesley Snipes starred as Blade the Vampire Hunter in three films beginning in 1998.</p>
<p>This is, however, the first Black-led superhero film since comic book movies became, in the words of <a href="https://books.google.ca/books?id=r4zdBwAAQBAJ">Liam Burke</a>, “modern Hollywood’s leading genre.” </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/206496/original/file-20180215-124890-6v5s6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/206496/original/file-20180215-124890-6v5s6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=930&fit=crop&dpr=1 600w, https://images.theconversation.com/files/206496/original/file-20180215-124890-6v5s6d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=930&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/206496/original/file-20180215-124890-6v5s6d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=930&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/206496/original/file-20180215-124890-6v5s6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1169&fit=crop&dpr=1 754w, https://images.theconversation.com/files/206496/original/file-20180215-124890-6v5s6d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1169&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/206496/original/file-20180215-124890-6v5s6d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1169&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cover, <em>Black Panther (2016)</em> #1.</span>
<span class="attribution"><span class="source">Grand Comics Database</span></span>
</figcaption>
</figure>
<p>Much as T’Challa’s first appearance in print — in the <em>Fantastic Four</em> issue #52 in July 1966 — predated the founding of the Black Panther Party by a few months; the decision to bring him to the silver screen 50 years later ran ahead of major shifts in the discourse about diversity and representation in the entertainment industries. </p>
<p>The project was announced as part of Phase Three of the Marvel Cinematic Universe in October 2014, a few months before <a href="http://www.reignofapril.com">April Reign</a> launched the hashtag <a href="https://mobile.twitter.com/search?q=%23OscarsSoWhite">#OscarsSoWhite</a> to draw attention to the racialized economy of recognition in Hollywood, and more than a year before the <a href="https://mobile.twitter.com/search?q=%23whitewashedOUT">#whitewashedOUT</a> campaign focused on the casting of white actors in roles written as Asian or Asian-American. It came before <em>Moonlight’s</em> dramatic win for Best Picture at the 2017 Academy Awards.</p>
<p>Sight still unseen by most, <em>Black Panther</em> has been embraced as a triumphant rejoinder in our long, difficult conversations about race and the legacies of colonialism and slavery. <a href="https://www.nytimes.com/2018/02/12/magazine/why-black-panther-is-a-defining-moment-for-black-america.html"><em>The New York Times Magazine</em></a> hails it as a “defining moment for black America,” while <a href="https://www.theglobeandmail.com/arts/film/the-black-panther-revolution-ishere/article37967876/"><em>the Globe and Mail</em></a> says its treatment of the Black experience “resonates across the diaspora.” </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/206493/original/file-20180215-124909-1p63jic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/206493/original/file-20180215-124909-1p63jic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/206493/original/file-20180215-124909-1p63jic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/206493/original/file-20180215-124909-1p63jic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/206493/original/file-20180215-124909-1p63jic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/206493/original/file-20180215-124909-1p63jic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/206493/original/file-20180215-124909-1p63jic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Michael B Jordan and Chadwick Boseman.</span>
<span class="attribution"><span class="source">(Marvel/Disney)</span></span>
</figcaption>
</figure>
<p>In a short video clip I first encountered on <a href="https://www.youtube.com/watch?v=7H97GhLWZR8">Twitter</a>, three young men admire the film’s poster, exclaiming, “This is what y’all feel all the time? I would love this country, too.” Activists, educators and scholars from racialized communities have long raised concerns about <a href="http://www.cjc-online.ca/index.php/journal/article/view/2286/3017">under-representation and stereotyping in the media</a> and <a href="http://www.racialequitytools.org/resourcefiles/Media-Impact-onLives-of-Black-Men-and-Boys-OppAgenda.pdf">their impact on self-esteem and identity</a>.</p>
<p>While it is difficult to draw a direct, causal line from watching a movie to an improved sense of self-worth or well-being, it is undeniable that <em>Black Panther</em> —with its nearly all-Black cast, stylish use of hip-hop, lush costuming, and setting in the proudly uncolonized, technologically advanced nation of Wakanda —is giving <a href="http://annenberg.usc.edu/sites/default/files/Dr_Stacy_L_Smith-Inequality_in_900_Popular_Films.pdf">many of us who have felt under-served by Hollywood</a> a language with which to speak our aspirations.</p>
<h2>Box office politics</h2>
<p>While echoing the broad picture of under-representation, <a href="http://bunchecenter.pre.ss.ucla.edu/wp-content/uploads/sites/82/2016/02/2016-Hollywood-Diversity-Report-2-25-16.pdf">research conducted by Darnell Hunt, Ana-Christina Ramón and Michael Tran at UCLA’s Ralph Bunche Centre for African American Studies</a> also points to the positive incentives towards diversity. Canada and the U.S., which together make up the “domestic” film market, are becoming more diverse, and young people, who are the biggest purchasers of cinema tickets, are the most diverse of all. </p>
<p>As a result, according to Hunt, Ramón and Tran, films with diverse casts have higher global box returns and higher returns on investment. In a <a href="https://www.nytimes.com/2018/02/12/movies/black-panther-marvel-chadwick-boseman-ryan-coogler-lupita-nyongo.html"><em>New York Times</em> roundtable</a>, Coogler suggested that commercial media production provided a space that could harmonize marginalized communities’ aspirations for representation with economic imperatives:</p>
<blockquote>
<p>They say it’s the studio system, but it’s really the people system. It’s who’s running the studio? How are they running it? When you look at Disney with [Tendo Nagenda, executive vice president for production at Walt Disney Studios, and Nate Moore, a producer at Marvel Studios and an executive producer of “Black Panther”], it’s a place that’s interested in representation, not just for the sake of representation, but representation because that’s what works, that’s what’s going to make quality stuff that the world is going to embrace, that’s what leads to success.</p>
</blockquote>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/206501/original/file-20180215-124890-f48x55.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/206501/original/file-20180215-124890-f48x55.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=251&fit=crop&dpr=1 600w, https://images.theconversation.com/files/206501/original/file-20180215-124890-f48x55.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=251&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/206501/original/file-20180215-124890-f48x55.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=251&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/206501/original/file-20180215-124890-f48x55.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=315&fit=crop&dpr=1 754w, https://images.theconversation.com/files/206501/original/file-20180215-124890-f48x55.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=315&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/206501/original/file-20180215-124890-f48x55.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=315&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The studio’s embrace of diversity may be sincere but it is also strategic.</span>
<span class="attribution"><span class="source">(Marvel/Disney)</span></span>
</figcaption>
</figure>
<p><em>Black Panther</em> is a case in point. Coogler and his stars speak movingly about the experience of making this film and what it means to them as African-Americans with more or less immediate connections to Africa. But, at the same time, the studio’s embrace of diversity is also a highly strategic move — 18 films into their mega-franchise. </p>
<p>While some critics have begun to call out the ossifying house style of “Marvel movies,” Coogler (like Taika Waititi, director of the recent <em>Thor: Ragnarok</em>) brings a distinctive aesthetic sensibility and critical reputation to bear. The studio may have gambled that the Black film-goers who supported recent films like <em>Hidden Figures</em> and <em>Get Out</em> would pick up the slack as producers reach deeper and deeper into Marvel Comics’ catalogue for characters with less existing brand recognition.</p>
<p>We have yet to see if the <a href="http://deadline.com/2018/02/black-panther-african-american-films-foreign-box-office-1202286475/">increasingly vital international audiences — often rhetorically brought up by studio executives as the obstacle to more diverse casting — will also respond positively</a>?</p>
<p>Marvel Studios and Disney did not make <em>Black Panther</em> in order to say something about race in America. It is, rather, a product designed to fit into a series, offering familiar pleasures with enough difference to keep the whole franchise interesting. </p>
<p>Yet, it arrives at a moment of possibility. Creators involved in its production, at the studio and on set, as well as audiences, have transformed it into a referendum on representation. </p>
<p>Putting different faces on movie screens will not solve all our problems, yet the <em>Black Panther</em> phenomenon demonstrates that people are crying out for chances to see themselves and their communities portrayed with dignity and diversity —as heroes, villains and everyone in between. Will the executives who control the purse strings listen ?</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/fsT5SyBLlIg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">(Marvel/Disney)</span></figcaption>
</figure><img src="https://counter.theconversation.com/content/91468/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Benjamin Woo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Black Panther arrives at a moment of possibility. Its popularity demonstrates that people are crying out for chances to see themselves and their communities portrayed with dignity—as heroes.Benjamin Woo, Assistant Professor, Carleton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/901332018-01-18T13:19:52Z2018-01-18T13:19:52ZA huge asteroid wiped out the dinosaurs, but what danger do smaller ones pose?<figure><img src="https://images.theconversation.com/files/202268/original/file-20180117-53299-cskvli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Don't panic...yet</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/lwpkommunikacio/7313468438">Lwp Kommunikáció/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>A small asteroid <a href="http://www.dailymail.co.uk/sciencetech/article-5228513/Asteroid-set-make-close-approach-Earth-HOURS.html">passed relatively close to Earth</a> this month, having been discovered just six days earlier. This might sound scary, but it’s unusual that such an object would actually collide with the Earth. </p>
<p>Each year about 50,000 tonnes of extraterrestrial material (rocks and dust) hits our planet. This comes as tiny pieces – even if it all came at once, it would be only slightly larger than the “lorry-sized” asteroid that passed us in January.</p>
<p>But while scientists can readily spot fairly large asteroids greater than about a kilometre across, what risk do such smaller asteroids that may be more difficult to track pose? Should we worry?</p>
<p>It is widely believed the dinosaurs <a href="https://theconversation.com/dinosaurs-could-have-avoided-mass-extinction-if-the-killer-asteroid-had-landed-almost-anywhere-else-87109">were wiped out</a> 65m years ago by an asteroid impact. The environmental changes that it caused – a rapid rise in atmospheric temperature and global forest fires, followed by plummeting temperatures and acidified ocean waters – were a consequence of the size of the asteroid, probably about 10km across. </p>
<p>This is almost three orders of magnitude larger in diameter, and about 30m times heavier, than the year’s worth of asteroids that hit us today.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/dpmXyJrs7iU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The Earth had a <a href="https://theconversation.com/the-five-greatest-balls-of-fire-over-earth-55454">brush with an object</a> estimated to be around 20 metres across almost five years ago over Chelyabinsk in Russia. Nobody saw it coming. Spectacular footage of the incoming fireball was recorded by commuters on their way to work, shocked to see the dark February morning lit by something originally thought to be a missile.</p>
<p>The rock exploded in the atmosphere, with many meteorite fragments scattered across the region. The largest piece, of about 600kg, was recovered several months later in an ice covered lake. Although many people were hurt when the object powered its way through the atmosphere, the injuries mostly came from window glass shattered by the atmospheric shock wave it caused.</p>
<p>The inhabitants of the Chelyabinsk region had a lucky escape – no crater was created by the asteroid because it burst into pieces about 30km up in the atmosphere. Luckily, this is the <a href="https://impact.ese.ic.ac.uk/ImpactEarth/index.html">most likely situation</a> for an object that size. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/202269/original/file-20180117-53295-bv74kw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/202269/original/file-20180117-53295-bv74kw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/202269/original/file-20180117-53295-bv74kw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/202269/original/file-20180117-53295-bv74kw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/202269/original/file-20180117-53295-bv74kw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/202269/original/file-20180117-53295-bv74kw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/202269/original/file-20180117-53295-bv74kw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Meteor Crater in Arizona.</span>
<span class="attribution"><span class="source">Kevin Walsh/wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>It is not until an asteroid is about 50 metres across that a crater is produced on impact. Even when it is two or three kilometres across – the size of <a href="https://en.wikipedia.org/wiki/Meteor_Crater">Meteor Crater in Arizona</a> – it is not near large enough to cause destruction on the global scale of the dinosaur extinction event. But it would certainly cause local problems if the impact was in an inhabited area. Imagine the asteroid that created the Meteor Crater – literally and figuratively – hitting central London, Washington or Mumbai.</p>
<h2>Monitoring threat</h2>
<p>There are several <a href="https://cneos.jpl.nasa.gov/">international observing programmes</a> using automated telescopes specifically dedicated to mapping all “Near Earth Objects”. These are asteroids with a closest approach to the sun of less than 1.3 Astronomical Units – one such unit is the distance between the Earth and the sun. A special watch is kept for “potentially hazardous objects”, which are Near Earth Objects over 150 metres in diameter with orbits that cross that of the Earth. </p>
<p>Fortunately, practically all of these objects are in stable orbits, and are not designated hazardous. Asteroids with sizes down to about five metres across can now be observed. Although, as the Chelyabinsk event illustrated, there are still objects that evade the watchers. Part of the reason that the Chelyabinsk object went undetected, was because it came into the atmosphere at a very low angle from the direction of the sun. But the main reason was the sheer number of such objects, and the relatively short time (about a decade) that we have been actively tracking them. </p>
<p>It is salutary to look at the number of detections of Near Earth Objects. <a href="https://www.minorplanetcenter.net/">The Minor Planet Center</a> maintains a database of observations, keeping a running total which, by the end of December 2017, stood at over 17,500. A further 28 have already been spotted this month. You can get an idea <a href="https://www.minorplanetcenter.net/iau/lists/InnerPlot2.html">here</a> where all these objects are relative to the Earth and the sun – I guarantee that you will be more than a little perturbed when you see how surrounded we are by these missiles. </p>
<p>One of the major problems that civilisation has is that while we are becoming incredibly efficient at spotting Near Earth Objects, we still cannot do anything about one that might be on a collision path with the Earth. NASA <a href="https://theconversation.com/how-to-capture-an-asteroid-and-why-we-should-go-to-such-trouble-58973">currently has a project</a>, DART (Double Asteroid Redirection Test), to redirect a threatening asteroid at the preliminary design phase. A spacecraft, about 1.5 metres across, will be aimed to crash into an asteroid (Didymos B) about 140 metres across. Didymos B orbits a primary body, Didymos A. The aim of the project is to change the orbit of Didymos B around its binary partner, while not altering the orbit of Didymos A around the sun.</p>
<p>DART is scheduled for launch in December 2020, intercepting Didymos in October 2022. So we have fewer than five years to wait before we find out whether we can protect our planet from its unruly neighbours.</p>
<p>For now, while small asteroids certainly can pose some danger, the threat is more regional than that posed by larger asteroids. So there is no need (yet) to start stockpiling baked beans and bottled water against our imminent demise by asteroid attack. The 50,000 tonnes of space material that hits Earth each year falls mainly as dust grains less than half a millimetre across. And given that we are all still here (at the time of writing…), it poses no threat to humanity.</p><img src="https://counter.theconversation.com/content/90133/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Monica Grady receives funding from the STFC, the UK Space Agency and the EU Horizon 2020 Program, She is a Research Fellow of the Natural History Museum and a Trustee of Lunar Mission One.</span></em></p>Small asteroids can be hard to spot. But what kind of threat do they pose to the Earth?Monica Grady, Professor of Planetary and Space Sciences, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/860532017-12-31T14:17:59Z2017-12-31T14:17:59ZLook up! Your guide to some of the best meteor showers for 2018<figure><img src="https://images.theconversation.com/files/199879/original/file-20171219-27547-1w0do8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The 2017 Geminids as seen from Ecuador, against the backdrop of the splendid Milky Way (centre) and the Large Magellanic Cloud (right).</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/ecuadordave/38237384725/">Flickr/David Meyer</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>This year gets off to a relatively slow start when it comes to seeing the annual major meteor showers.</p>
<p>The Quadrantids, one of the big three annual showers, are lost to the vagaries of the full Moon in early January. </p>
<p>But the year’s other two most active annual showers – the Perseids (in August) and Geminids (in December) – are set to put on fine displays. </p>
<p>So when and where should you look to have the best chance of seeing <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">nature’s fireworks</a>?</p>
<p>Here we present the likely meteoric highlights of 2018. These are the meteor showers most likely to put on a good show this year.</p>
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Read more:
<a href="https://theconversation.com/stars-that-vary-in-brightness-shine-in-the-oral-traditions-of-aboriginal-australians-85833">Stars that vary in brightness shine in the oral traditions of Aboriginal Australians</a>
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<p>For each shower, we give the forecast activity period and the predicted time of maximum. We also provide charts showing you where to look, and give the peak rates that could be seen under perfect conditions (known as the maximum Zenithal Hourly Rate, or ZHR). </p>
<p>The actual rate you see will always be lower than this value - but the higher a shower’s radiant in the sky and the darker the conditions, the closer the observed rate will get to this ideal value.</p>
<p>To see the best rates it is well worth trying to <a href="http://darksitefinder.com/map/">find a good dark site</a>, far from street lights. Once outside, make sure to give your eyes plenty of time to adapt to the darkness (<a href="https://www.telescope.com/Articles/Equipment/Binoculars/Seeing-in-the-Dark/pc/9/c/192/sc/195/p/99833.uts">at least half an hour</a>).</p>
<p>Showers that can only be seen from one hemisphere are denoted by either [N] or [S], with those that can be seen globally marked as [N/S]. </p>
<h2>Lyrids [N/S; N favoured]</h2>
<h3>Active: April 14-30</h3>
<h3>Maximum: April 22, 6pm UT = April 23, 2am AWST (WA) = 4am AEST (QLD/NSW/ACT/Vic/Tas)</h3>
<h3>ZHR: 18+</h3>
<h3>Parent: <a href="https://books.google.com.au/books?id=14zKCQAAQBAJ&pg=PA80&lpg=PA80&dq=comet+thatcher&source=bl&ots=JDPIo8sePG&sig=_v5sM9Y7oPo9fWJmn_RHphpDTRs&hl=en&sa=X&ved=0ahUKEwis79LG05XYAhXCVZQKHWkwDSA4FBDoAQguMAE#v=onepage&q=comet%20thatcher&f=false">Comet C/1861 G1 (Thatcher)</a></h3>
<p>The Lyrids hold the record for the shower with the longest recorded history, having been observed since <a href="https://www.space.com/36550-history-lyrid-meteor-shower-2017.html">at least 687BC</a>.</p>
<p>That longevity is linked to the orbit of the Lyrid’s parent comet, discovered in 1861 by A. E. Thatcher. Comet Thatcher moves on a highly inclined, eccentric orbit, swinging through the inner Solar system every 415 years or so. Its most recent approach to Earth was in 1861.</p>
<p>Compared with many other comets, Thatcher’s orbit is relatively stable, as the only planet with which it can experience close encounters is Earth. This means the meteors it sheds continue to follow roughly the same orbit. </p>
<p>Over the millennia, that shed debris has spread all around the comet’s vast orbit, meaning that for thousands of years, every time Earth intersects Comet Thatcher’s orbit, the Lyrids have been seen, as regular as clockwork.</p>
<p>One study of the orbits of Lyrid meteors even suggests the shower may have been active for <a href="http://adsabs.harvard.edu/abs/1997MNRAS.289..721A">at least a million years</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199373/original/file-20171215-26009-1rz2nbv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199373/original/file-20171215-26009-1rz2nbv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199373/original/file-20171215-26009-1rz2nbv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199373/original/file-20171215-26009-1rz2nbv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199373/original/file-20171215-26009-1rz2nbv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199373/original/file-20171215-26009-1rz2nbv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199373/original/file-20171215-26009-1rz2nbv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199373/original/file-20171215-26009-1rz2nbv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Across Australia, the Lyrids are best seen an hour before sunrise, when the radiant is at its highest [Brisbane 5am].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>These days, the Lyrids are usually a moderately active shower, producing somewhere between 10 and 20 fast, bright meteors per hour at their peak. Occasionally, though, the Lyrids have thrown up a surprise, with rates climbing far higher for a period of several hours. </p>
<p>The best of those outbursts seem to occur every 60 years or so, with the most recent occurring in 1982 when observed rates reached or exceeded 90 per hour. </p>
<p>No such outburst is predicted for 2018, but even in quiet years, the Lyrids are still a fun shower to observe. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199376/original/file-20171215-17869-py3oy8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199376/original/file-20171215-17869-py3oy8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199376/original/file-20171215-17869-py3oy8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=505&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199376/original/file-20171215-17869-py3oy8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=505&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199376/original/file-20171215-17869-py3oy8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=505&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199376/original/file-20171215-17869-py3oy8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=635&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199376/original/file-20171215-17869-py3oy8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=635&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199376/original/file-20171215-17869-py3oy8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=635&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">From the USA, the radiant is well placed from late evening until early morning [Chicago 11pm].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>They are best seen from northern latitudes, but their radiant is far enough south for observers throughout Australia to observe them in the hours before dawn. </p>
<p>For observers at mid-northern latitudes, the Lyrid radiant reaches suitable altitude by about 11pm local time. Viewers in the southern hemisphere have to wait until the early hours of the morning before reasonable rates can be observed.</p>
<p>The forecast time of maximum this year favours observers in Australia and east Asia but the timing of maximum has been known to vary somewhat, so observers around the globe will likely be keeping their eyes peeled, just in case!</p>
<h2>Perseids [N]</h2>
<h3>Active: July 17 - August 24</h3>
<h3>Maximum: August 12, 8pm UT - August 13, 8am UT = from August 12, 9pm BST (UK) = 10pm CEST (Europe) = 6pm EDT (East Coast, US) = 3pm PDT (West Coast, US) for 12 hours</h3>
<h3>ZHR: 110</h3>
<h3>Parent: <a href="http://www.planetsedu.com/comet/swift-tuttle/">Comet 109P/Swift-Tuttle</a></h3>
<p>For observers in the northern hemisphere, the Perseids are a spectacular summer highlight. At their peak, rates often reach or exceed 100 meteors per hour, and they are famed for their frequent spectacular fireballs. </p>
<p>The Perseids are probably the best known and most widely observed of all modern meteor showers. They are remarkably consistent, with peak rates usually visible for a couple of evenings, and fall in the middle of the northern hemisphere summer holiday season. The warm nights and frequent clear skies at that time of year make the shower a real favourite!</p>
<p>Like the Lyrids, the Perseids have a long and storied history, having been observed for at least 2,000 years. Their parent comet, 109P/Swift-Tuttle, is a behemoth, with the largest nucleus of the known periodic comets - some 26km in diameter.</p>
<p>It has likely moved on its current orbit for tens of thousands of years, all the time laying down the debris that gives us our annual Perseid extravaganza. It will next swing past Earth in 2126 when it will be a spectacular naked eye object.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199382/original/file-20171215-17848-4xam1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199382/original/file-20171215-17848-4xam1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199382/original/file-20171215-17848-4xam1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=419&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199382/original/file-20171215-17848-4xam1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=419&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199382/original/file-20171215-17848-4xam1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=419&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199382/original/file-20171215-17848-4xam1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199382/original/file-20171215-17848-4xam1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199382/original/file-20171215-17848-4xam1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=527&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">From the UK, the Perseids radiant is visible all night and summer is the perfect time for meteor watching [Greenwich 9pm].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>This year the forecast maximum for the Perseids favours observers in Europe, although given the length of peak activity, any location in the northern hemisphere has the potential to see a spectacular show on the night of August 12. </p>
<p>But don’t despair if it’s cloudy that night, as the Perseids have a relatively broad period of peak activity, meaning that good rates can be seen for a few days either side of their peak. </p>
<p>In 2018, the peak of the Perseid shower coincides with the New Moon, and so is totally unaffected by moonlight, which makes this an ideal year to observe the shower.</p>
<p>The further north you are, the earlier the shower’s radiant will be visible. But reasonable rates can typically be seen any time after about 10pm, local time. The later in the night you observe, the better the rates will be, as the radiant climbs higher into the sky.</p>
<p>It is not uncommon for enthusiastic observers to watch the shower until dawn on the night of maximum, seeing several hundred meteors in a single night.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199876/original/file-20171219-27562-s59mse.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199876/original/file-20171219-27562-s59mse.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199876/original/file-20171219-27562-s59mse.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=419&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199876/original/file-20171219-27562-s59mse.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=419&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199876/original/file-20171219-27562-s59mse.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=419&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199876/original/file-20171219-27562-s59mse.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199876/original/file-20171219-27562-s59mse.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199876/original/file-20171219-27562-s59mse.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A fantastic Perseids display from 2016 over Austria.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/michael_karrer/4910137746/">Flickr/Michael Karrer</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>Draconids [N]</h2>
<h3>Active: October 6-10</h3>
<h3>Maximum: October 9, 12:10am UT = 1:10am BST (UK) = 2:10am CEST (Europe)</h3>
<h3>ZHR: 10+</h3>
<h3>Parent: <a href="http://cometography.com/pcomets/021p.html">Comet 21P/Giacobini-Zinner</a></h3>
<p>The Draconids are a fascinating meteor shower, although in most years, somewhat underwhelming. Unlike the previous showers, the Draconids are a relatively young meteor shower that can vary dramatically from one year to the next. </p>
<p>First observed less than a century ago, the Draconids (also known as the Giaocobinids) are tied to a <a href="http://astronomy.swin.edu.au/cosmos/J/Jupiter-family+Comets">Jupiter-family comet</a> called <a href="https://solarsystem.nasa.gov/planets/21pgiacobinizinner/indepth">21P/Giacobini-Zinner</a>. </p>
<p>That comet was the first to be visited by a spacecraft, and has frequent close encounters with Jupiter, which continually nudges its orbit around. These encounters also perturb the meteor stream the comet is laying down, sometimes enhancing rates at Earth and sometimes diminishing them.</p>
<p>In the early 20th century, it was realised that Comet Giacobini-Zinner’s orbit comes close enough to Earth that we might be able to see meteors as we plough through the debris it leaves behind.</p>
<p>This led to the first predictions of Draconid activity. Sure enough, in 1920, the great meteor observer <a href="http://hyperion2.cc.uregina.ca/%7Eastro/DEN/short_bio.pdf">W. F. Denning</a> confirmed the existence of the shower, with a mere five meteors observed between October 6 and October 9.</p>
<p>In 1933 and 1946, the Draconids produced two of the greatest meteor displays of the 20th century - great storms, with peak rates of several thousand meteors per hour. In those years, Earth crossed the comet’s orbit just a month or two after the comet passed through perihelion (closest approach to the Sun), and Earth ploughed through dense material in the comet’s wake.</p>
<p>After 1946, the Draconids went quiet, all but vanishing from our skies. Jupiter had swung the comet onto a less favourable orbit. Only a few Draconids were seen in 1972, then again in 1985 and 1998.</p>
<p>The late 1990s saw a renaissance in our ability to predict and understand meteor showers, born of <a href="https://leonid.arc.nasa.gov/history.html">enhanced activity exhibited by the Leonid meteor shower</a>. Using the techniques developed to study the Leonids, astronomers predicted enhanced activity from the Draconids in 2011, and the predicted outburst duly occurred, with rates of around 300 meteors per hour being observed.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199385/original/file-20171215-17878-ljdv6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199385/original/file-20171215-17878-ljdv6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199385/original/file-20171215-17878-ljdv6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199385/original/file-20171215-17878-ljdv6c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199385/original/file-20171215-17878-ljdv6c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199385/original/file-20171215-17878-ljdv6c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199385/original/file-20171215-17878-ljdv6c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199385/original/file-20171215-17878-ljdv6c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Europe is well placed to catch some Draconids streaming from the eye of the dragon, near the star Rastaban [Paris 12:30am].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>This year comet Giacobini-Zinner once again passes through perihelion and swings close to Earth’s orbit. The chances are good that the shower will be active - albeit unlikely to produce a spectacular storm. </p>
<p>Modelling suggests that rates of 20 to 50 faint meteors per hour might be seen around 12:14am UT on October 9. Other models suggest that rates will peak about 45 minutes earlier, with lower rates of 15 to 20. </p>
<p>The Draconid radiant is circumpolar (that is, it never sets) for locations north of 44°N, and is highest in the sky before midnight. This year, the Moon is new at the time of the forecast peak, which is ideally timed for observers in Europe.</p>
<p>If skies are clear that evening, it is well worth heading out at around 11:30pm BST on October 8 (12:30am CEST on October 9) and spending a couple of hours staring north, just in case the Draconids put on another spectacular show.</p>
<h2>Taurids [N/S]</h2>
<h3>Active: September 10 - December 10</h3>
<h3>Maxima: October 10 (Southern Taurids); November 12 (Northern Taurids)</h3>
<h3>ZHR: 5 + 5</h3>
<h3>Parent: <a href="http://cometography.com/pcomets/002p.html">Comet 2P/Encke</a></h3>
<p>Of all the year’s meteor showers, the one that dumps the greatest amount of dust into Earth’s atmosphere are the Taurids. The inner Solar system contains a vast swathe of debris known as the Taurid stream. It is so spread out that Earth spends a quarter of the year passing through it. </p>
<p>In June, that debris spawns the Daytime Taurid meteor shower, which (as the name suggests) occurs during daylight hours, and is only really known thanks to radio observations. </p>
<p>After leaving the stream for a little while, Earth penetrates it again at the start of September, and activity continues right through until December. Hourly rates fluctuate up and down, with several distinct peaks and troughs through October and November.</p>
<p>The Taurid stream is complex - with at least two main components, known as the northern and southern branches. Typically, the Southern Taurids are active a little earlier in the year and reach their peak about a month before the northern branch. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199865/original/file-20171219-27557-a0vuay.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199865/original/file-20171219-27557-a0vuay.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199865/original/file-20171219-27557-a0vuay.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=522&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199865/original/file-20171219-27557-a0vuay.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=522&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199865/original/file-20171219-27557-a0vuay.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=522&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199865/original/file-20171219-27557-a0vuay.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=657&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199865/original/file-20171219-27557-a0vuay.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=657&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199865/original/file-20171219-27557-a0vuay.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=657&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">During northern autumn, the Taurids can be seen radiating from the western sky before dawn [Paris 6:30am October 10].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199866/original/file-20171219-27538-1qprqfj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199866/original/file-20171219-27538-1qprqfj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199866/original/file-20171219-27538-1qprqfj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=538&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199866/original/file-20171219-27538-1qprqfj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=538&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199866/original/file-20171219-27538-1qprqfj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=538&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199866/original/file-20171219-27538-1qprqfj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=676&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199866/original/file-20171219-27538-1qprqfj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=676&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199866/original/file-20171219-27538-1qprqfj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=676&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For the southern spring, the Taurids radiate from the northern sky before dawn [Melbourne 3:30am November 12].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>The Taurids are slow meteors and feature plenty of bright fireballs. So even though their rates are low, they are well worth looking out for, particularly when other showers are also active, such as the Draconids, the Orionids and the Leonids.</p>
<p>Put together, these showers make the northern autumn or the southern spring a great time to get out and look for natural fireworks.</p>
<h2>Orionids [N/S]</h2>
<h3>Active: October 2 - November 7</h3>
<h3>Maximum: October 21</h3>
<h3>ZHR: 20+</h3>
<h3>Parent: <a href="http://www.ianridpath.com/halley/halley6.htm">Comet 1P/Halley</a></h3>
<p>Twice a year, Earth runs through the stream of debris littered around the orbit of <a href="http://www.ianridpath.com/halley/halley6.htm">Comet 1P/Halley</a>. Throughout the month of October this gives rise to the Orionid meteor shower.</p>
<p>The Orionids are a fairly reliable meteor shower with a long, broad maximum. Typically, peak rates can last for almost a week, centred on the nominal maximum date. Throughout that week, Orionid rates can fluctuate markedly, leading to a number of distinct maxima and minima. </p>
<p>Orionid meteors are fast - much faster than the Taurids that are active at the same of year. Like the Taurids, they are often bright, the result of the high speed at which the meteoroids hit Earth’s atmosphere. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199387/original/file-20171215-17854-1ybanyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199387/original/file-20171215-17854-1ybanyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199387/original/file-20171215-17854-1ybanyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=587&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199387/original/file-20171215-17854-1ybanyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=587&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199387/original/file-20171215-17854-1ybanyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=587&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199387/original/file-20171215-17854-1ybanyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=737&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199387/original/file-20171215-17854-1ybanyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=737&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199387/original/file-20171215-17854-1ybanyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=737&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Before sunrise, Orion stands upright in the southwest as seen from the northern hemisphere [Chicago 5am].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199388/original/file-20171215-17857-nnk05b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199388/original/file-20171215-17857-nnk05b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199388/original/file-20171215-17857-nnk05b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=565&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199388/original/file-20171215-17857-nnk05b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=565&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199388/original/file-20171215-17857-nnk05b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=565&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199388/original/file-20171215-17857-nnk05b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=710&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199388/original/file-20171215-17857-nnk05b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=710&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199388/original/file-20171215-17857-nnk05b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=710&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">But from the southern hemisphere Orion appears to be standing on his head, in the northern sky before dawn [Sydney 5am].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>The Orionid radiant rises in the late evening and is only really high enough in the sky for reasonable rates to be seen after midnight. As a result, the best rates are usually observed in the hours before dawn. </p>
<p>This works well this year, as the Moon will be in its waxing gibbous phase, setting some time after midnight and leaving the sky dark, allowing us to watch for pieces of the most famous comet of them all.</p>
<h2>Geminids [N/S]</h2>
<h3>Active: December 4-17</h3>
<h3>Maximum: December 14, 12:30pm UT = Australia: December 14, 8pm AWST (WA) = 10:30pm (QLD) = 11:30pm AEST (NSW/ACT/Vic/Tas) = United States: December 14, 7:30am (EST) = 5:30am (PST) = 2:30am (Hawaii)</h3>
<h3>ZHR: 120</h3>
<h3>Parent: <a href="https://echo.jpl.nasa.gov/asteroids/Phaethon/Phaethon_planning.2017.html">Asteroid 3200 Phaethon</a></h3>
<p>As the year comes to a close, we reach the most reliable and spectacular of the annual meteor showers – <a href="https://theconversation.com/this-years-geminid-meteor-shower-will-be-a-true-spectacle-52068">the Geminids</a>. Unlike the Perseids and the Lyrids, which have graced our skies for thousands of years, the Geminids are a relatively new phenomenon. </p>
<p>They were first observed just 150 years ago, and through the first part of the 20th century were a relatively minor shower. But since then rates have improved decade-on-decade, to the point where they are now the best of the annual showers, bar none.</p>
<p>The reason for their rapid evolution is that their orbit (and that of their parent body, the asteroid Phaethon) is shifting rapidly over time, precessing around the Sun (wobbling like a slow spinning top). As it does so, the centre of Phaethon’s orbit, and the centre of the Geminid stream, are moving ever closer to Earth. </p>
<p>For northern locations, the radiant rises shortly after sunset, and good rates can be seen from mid-evening onwards. For observers in the southern hemisphere, the radiant rises later, so good rates are delayed until later at night (<a href="https://theconversation.com/this-years-geminid-meteor-shower-will-be-a-true-spectacle-52068">as detailed in our 2015 report on the shower</a>).</p>
<p>Although the time of maximum this year seems to favour observers in the Americas and Australia, peak rates from the Geminids usually last around 24 hours, and so good rates should be visible around the globe.</p>
<p>This year the maximum falls a day before the Moon reaches first quarter so the best rates are visible (after midnight, local time) when the Moon will have set and moonlight will not interfere.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199391/original/file-20171215-17869-icjny5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199391/original/file-20171215-17869-icjny5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199391/original/file-20171215-17869-icjny5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199391/original/file-20171215-17869-icjny5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199391/original/file-20171215-17869-icjny5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199391/original/file-20171215-17869-icjny5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199391/original/file-20171215-17869-icjny5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199391/original/file-20171215-17869-icjny5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Australia’s summer meteor shower, the consistent and spectacular Geminids in the early morning sky [Brisbane 4am].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/199392/original/file-20171215-17878-kzgbgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/199392/original/file-20171215-17878-kzgbgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/199392/original/file-20171215-17878-kzgbgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=524&fit=crop&dpr=1 600w, https://images.theconversation.com/files/199392/original/file-20171215-17878-kzgbgp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=524&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/199392/original/file-20171215-17878-kzgbgp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=524&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/199392/original/file-20171215-17878-kzgbgp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=659&fit=crop&dpr=1 754w, https://images.theconversation.com/files/199392/original/file-20171215-17878-kzgbgp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=659&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/199392/original/file-20171215-17878-kzgbgp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=659&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Geminids appear high overhead over American skies in winter [Los Angeles midnight].</span>
<span class="attribution"><span class="source">Museums Victoria/stellarium</span></span>
</figcaption>
</figure>
<p>Given that rates from the Geminids continue to climb, the estimated ZHR of 120 is likely to be somewhat conservative. Rates in excess of 130, and even as high as 200 per hour, have been seen in recent years.</p>
<p>Geminids are medium-speed meteors and are often bright. The individual meteors also seem to last just that bit longer than other showers, a fact likely related to their parent object’s rocky nature. </p>
<p>Wherever you are on the planet, the Geminids are a fantastic way to bring the year to an end, and we will hopefully be treated to a magnificent display this year.</p><img src="https://counter.theconversation.com/content/86053/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Your guide to some of the best meteor showers for 2018. Where to look and when in both the northern and southern skies to catch nature’s fireworks.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandTanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/827982017-08-23T08:22:33Z2017-08-23T08:22:33ZHere’s the blueprint for a global fireball observatory – and why we need one<figure><img src="https://images.theconversation.com/files/182802/original/file-20170821-4987-91zqm6.png?ixlib=rb-1.1.0&rect=0%2C2%2C786%2C519&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> </figcaption></figure><p>Bright shooting stars are one of nature’s great wonders. Like the one in the main image, which was <a href="http://www.devonlive.com/watch-as-a-fireball-lights-up-the-skies-over-south-devon/story-30369572-detail/story.html">visible from</a> Devon in the south-west of England in June, these fireballs are caused by space rocks hitting Earth’s atmosphere. The friction forces them to slow down, producing a tremendous amount of heat at the same time. If the rock is big enough, a fragment will survive this fiery transition and fall to Earth as a meteorite. </p>
<p>Planetary scientists study these rocks to extract clues as to how our solar system formed. But this work is complicated by the fact that we don’t know where in the solar system most of Earth’s <a href="https://www.lpi.usra.edu/meteor/">50,000 or so meteorites</a> came from. </p>
<p>To improve this situation, you have to determine a new fireball’s orbit once it breaches Earth’s atmosphere. This means observing it from multiple angles. You then ideally want to recover the meteorite before the weather changes the chemistry of the sample – usually in the first shower of rain. A new network of cameras is being set up in the UK to help in this endeavour, phase two of a global network that started five years ago in Australia. </p>
<h2>Fireball hunting</h2>
<p>Meteorites are arriving from outer space all the time. About 50 tonnes of extraterrestrial material enters Earth’s atmosphere each year. Most are sand-sized particles known as cosmic dust, including the majority of the <a href="https://www.space.com/37829-perseid-meteor-shower-2017-skywatcher-photos.html">Perseid meteor shower</a> that took place earlier in August. </p>
<p>But even over a relatively small space like the UK, <a href="http://www.lpi.usra.edu/books/MESSII/9021.pdf">about 20 meteorites</a> of a searchable size land each year – of which the Devon fireball was a good example. Most are barely 10g, about the size of a six-sided dice. Two or three will be bigger; usually up to a kilogram in mass or the size of a tennis ball. </p>
<p>This is but a remnant of the 6,000 to 20,000 meteorites in the same size range that we see each year in the land mass of the world as a whole. Yet observing and finding these is still no mean feat. To date, only around 30 meteorites <a href="http://www.meteoriteorbits.info/">have been recovered</a> after their fireball was observed. This has mostly been through remote camera networks including in Canada, France, the Czech Republic, Finland and Australia. </p>
<p>Such networks are continuously imaging the night sky over a huge area, which is ideal for tracking orbits back to space and reaching the landing site fast. I used to work as a researcher for the <a href="https://theconversation.com/how-to-find-a-meteorite-thats-fallen-to-earth-52906">Desert Fireball Network</a> in Australia. Since it was set up five years ago, its 52 cameras have found four meteorites. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/182826/original/file-20170821-4969-9p19yd.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/182826/original/file-20170821-4969-9p19yd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182826/original/file-20170821-4969-9p19yd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182826/original/file-20170821-4969-9p19yd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182826/original/file-20170821-4969-9p19yd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182826/original/file-20170821-4969-9p19yd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182826/original/file-20170821-4969-9p19yd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182826/original/file-20170821-4969-9p19yd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">One of the cameras in the Nullarbor Desert in southern Australia.</span>
<span class="attribution"><span class="source">DFN</span></span>
</figcaption>
</figure>
<p>The project to extend the Desert Fireball Network has already seen three high-resolution cameras installed in different parts of England in recent months, along with sophisticated image-processing software. A further seven will be in place by next summer, in a collaboration between Imperial College London, University of Glasgow, the Open University, the Natural History Museum and Curtin University in Perth, Australia. </p>
<p>The new network will track any fast-moving object flying across the skies above the UK, including things like satellites. It will complement an existing network of 30 video cameras called the <a href="https://ukmeteornetwork.co.uk">UK Meteor Observation Network</a>, which is already run by citizen scientists to spot fireballs and smaller meteors. UKMON focuses on capturing images rather than meteorite recovery. The two operations will share data, enhancing one another’s abilities. There are also plans to extend the new network to the US, South America, New Zealand and Saharan Africa in the next few years. </p>
<p>The challenges facing the UK operation are quite different to those in Australia. Where the Australian network needs to be able to survive unattended in the brutal desert heat, the UK cameras will work in a distinctly colder, wetter climate. </p>
<p>They will have to contend with light pollution, unpredictable weather and significant cloud cover, reducing the number of nights they will be able to take images. But most problematic of all is the ground itself. The Australian outback is ideal for meteorite hunting: uniformly red and with very little vegetation, meaning you can spot a little black rock from several hundred metres. By contrast, the UK’s lush vegetation and woodland can easily camouflage meteorites.</p>
<p>Yet the UK network also has advantages. Most cameras will be within a day’s drive and connected to the internet to provide instant warnings when a camera needs some tender loving care – the Australian cameras tend to be on rougher terrain that takes longer to reach and many are not internet-connected. At the same time, the UK population density is such that quite a lot of people are likely to spot a large fireball and take pictures on their smartphones. </p>
<h2>Apps upside your head</h2>
<p>Unlocking the assistance of these 65m independent autonomous observatories in the UK is part of the project. The Australian fireball team has developed an app in conjunction with US software consultancy ThoughtWorks. Known as Fireballs in the Sky and free for <a href="https://itunes.apple.com/gb/app/fireballs-in-the-sky/id709019924?mt=8">Apple</a> and <a href="https://play.google.com/store/apps/details?id=com.tw.fireballs&hl=en_GB">Android</a> phones alike, it allows anyone to become a citizen scientist. Users can report any fireball, as well as getting details of the next big meteor shower and where in the sky to look for it – and here’s a grab of what it looks like.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/182827/original/file-20170821-4938-lfmj1h.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/182827/original/file-20170821-4938-lfmj1h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/182827/original/file-20170821-4938-lfmj1h.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=531&fit=crop&dpr=1 600w, https://images.theconversation.com/files/182827/original/file-20170821-4938-lfmj1h.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=531&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/182827/original/file-20170821-4938-lfmj1h.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=531&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/182827/original/file-20170821-4938-lfmj1h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=667&fit=crop&dpr=1 754w, https://images.theconversation.com/files/182827/original/file-20170821-4938-lfmj1h.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=667&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/182827/original/file-20170821-4938-lfmj1h.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=667&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The app.</span>
<span class="attribution"><span class="source">DFN/ThoughtWorks</span></span>
</figcaption>
</figure>
<p>The app is already up and running. In fact, the latest recovered meteorite in Australia, called Dingle Dell, was <a href="http://www.abc.net.au/news/2016-11-22/meteorite-recovered-with-the-help-of-dedicated-star-gazers/8046880">initially observed</a> by a citizen scientist using it. </p>
<p>This made it possible to find the pristine meteorite before delicate minerals inside it were irreparably altered or washed away by rain, revealing extraterrestrial salts formed early in the solar system that usually quickly disappear on the surface of Earth. These could potentially tell us things about the origins of life and water on our planet. </p>
<p>These kinds of exciting discoveries give a taste of why it will be a race against time to recover the first meteorite tracked by the UK network. So do we have any volunteers?</p><img src="https://counter.theconversation.com/content/82798/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Daly’s PhD was funded under The Australian Research Council Laureate fellowship awarded to Professor Phil Bland. Luke is an associate of the Royal School of Mines at Imperial College London, and a member of the Meteoritical Society.</span></em></p><p class="fine-print"><em><span>Gareth Collins has received funding from the UK Research Councils (NERC, STFC & EPSRC).</span></em></p><p class="fine-print"><em><span>Martin Suttle receives funding from the STFC. </span></em></p>Ten new remote cameras will soon be scouring the British night skies for meteorites.Luke Daly, Research Associate, School of Geographical and Earth Sciences, University of GlasgowGareth Collins, Reader in Planetary Science, Imperial College LondonMartin D. Suttle, Researcher in Meteoritics and Planetary Science, Imperial College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/780292017-08-01T20:15:15Z2017-08-01T20:15:15ZCurious Kids: What’s going to happen to the Sun in the future? Will it explode?<figure><img src="https://images.theconversation.com/files/171265/original/file-20170529-25219-8dc8r2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Sun is currently middle-aged, having celebrated its 4,568,000,000th birthday at some point in the last million years. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/naveenlreddy/17161922320/in/photolist-s9xkAq-aojzAy-cyGtLw-rypHLX-nXYPQk-fAxJHS-kbRGf2-9jeW4L-9jFSqX-cw4eEf-9eWgU9-9uMncH-oNyX5A-9jc8An-cyGsLN-kEz2gA-9wiPQB-o6n6sK-89azDZ-qTHZUL-aEofGr-pLgzgj-6gfeo-rKK5u4-d5VQnd-baN8ra-nuWFkB-cbW1Nf-7fXRv9-6ohay-r2m8Ye-paYQjg-q3X2Fs-aEtJdy-bsqCRo-dzuy5u-b2xbSe-dwuyhg-q177Hv-9JLvUQ-aK2f6Z-9NAEu9-85MnZg-s2LUrY-9BeNCY-nV4iMg-97NQMe-aAiAxY-avgC7j-2TxZ5z">Flickr/ChopWood CarryWater</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><em>This is an article from <a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a>, a new series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!</em> </p>
<hr>
<blockquote>
<p><strong>What is going to happen to the sun in the future? Will it explode? Will it burn out? Is it getting closer to the Earth? Will it drop like a shooting star? Sophie (age 12) and Max (age 10), Melbourne.</strong></p>
</blockquote>
<p>That’s a fantastic set of questions - and I’ll try to answer all of them. I’ll start with the last, and work backwards from there.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FyLSjkOV2H8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Will the Sun drop like a shooting star?</h2>
<p>When the Sun does reach the end of its life, it won’t fall to Earth - but we’ll come to that in a moment.</p>
<p>Although people like to imagine that shooting stars are stars falling from the heavens, they’re actually just bits of dust, burning up harmlessly way overhead. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171132/original/file-20170526-6377-caognc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171132/original/file-20170526-6377-caognc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171132/original/file-20170526-6377-caognc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171132/original/file-20170526-6377-caognc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171132/original/file-20170526-6377-caognc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171132/original/file-20170526-6377-caognc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171132/original/file-20170526-6377-caognc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171132/original/file-20170526-6377-caognc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A meteor (or ‘shooting star’) burning bright over the telescopes at Chile’s Paranal Observatory. It is not a star falling to Earth - but a beautiful sight nonetheless.</span>
<span class="attribution"><span class="source">ESO/S. Guisard</span></span>
</figcaption>
</figure>
<p>On any clear night of the year, if you go outside and watch the sky, you will eventually see a few shooting stars (“meteors”). But on some nights, you can see tens, or even hundreds per hour. <a href="https://theconversation.com/look-up-your-guide-to-some-of-the-best-meteor-showers-for-2017-64885">Here’s a calendar of the year’s best “meteor showers”</a>, if you want to know when to look, and <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">here’s an Explainer</a>, if you want to learn more about meteors.</p>
<h2>Is the Sun getting closer to the Earth?</h2>
<p>The Earth moves around the Sun on a slightly egg-shaped orbit, so it is sometimes a bit closer to the Sun, and sometimes a bit further away. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171126/original/file-20170526-6367-17j7339.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171126/original/file-20170526-6367-17j7339.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171126/original/file-20170526-6367-17j7339.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171126/original/file-20170526-6367-17j7339.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171126/original/file-20170526-6367-17j7339.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171126/original/file-20170526-6367-17j7339.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171126/original/file-20170526-6367-17j7339.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171126/original/file-20170526-6367-17j7339.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The orbits of Mercury, Venus, Earth and Mars, are all a bit ‘egg-shaped’ - but if you came back in a billion years, the planets would still be moving on almost the same orbits, at the same distances from the Sun.</span>
<span class="attribution"><span class="source">Danial79/Wikipedia</span></span>
</figcaption>
</figure>
<p>The change in distance is small compared to the size of Earth’s orbit, though - and overall, the average distance from the Earth to the Sun now is no different to what it was when the dinosaurs walked the Earth.</p>
<h2>What is going to happen to the Sun in the future? Will it explode? Will it burn out?</h2>
<p>The Sun won’t explode. Some stars do explode at the end of their lives, an explosion that outshines all the other stars in their galaxy added together - something we call a “supernova”. That spectacular fate only happens for the most massive stars, however. Smaller stars like the Sun follow a different route to their end.</p>
<p>The first thing that will happen to the Sun will happen really slowly. The Sun is currently middle-aged, having celebrated its 4,568,000,000th birthday at some point in the last million years. </p>
<p>Over that time, the Sun hasn’t really changed much - but it has gradually got a bit brighter. That brightening will carry on into the future - and eventually the Earth will get so hot that the oceans will boil!</p>
<p>Don’t panic, though - that won’t happen <a href="https://theconversation.com/the-sun-wont-die-for-5-billion-years-so-why-do-humans-have-only-1-billion-years-left-on-earth-37379">for at least another five hundred million years</a>.</p>
<p>Eventually (in five or seven billion years time), the Sun’s life will come to an end. </p>
<p>Our star will swell up, becoming something called a “Red Giant” star. It might even get so big that it swallows the Earth whole. As it swells, it will cool down, shining red or orange, like the bright star Betelgeuse in the constellation Orion.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171129/original/file-20170526-6385-1wf5lr6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171129/original/file-20170526-6385-1wf5lr6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171129/original/file-20170526-6385-1wf5lr6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=925&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171129/original/file-20170526-6385-1wf5lr6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=925&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171129/original/file-20170526-6385-1wf5lr6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=925&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171129/original/file-20170526-6385-1wf5lr6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1162&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171129/original/file-20170526-6385-1wf5lr6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1162&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171129/original/file-20170526-6385-1wf5lr6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1162&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Betelgeuse, a red supergiant star, shines brightly at the left-hand shoulder of Orion. Betelgeuse is a much more massive star than the Sun, and when it dies (in the next million years) it will explode as a supernova!</span>
<span class="attribution"><span class="source">Rogelio Bernal Andreo</span></span>
</figcaption>
</figure>
<p>That stage of the Sun’s life will last just a few million years, at most. Then, the Sun will die. Not with a bang, but more of a whoosh.</p>
<p>The outer layers of the Sun will blow away, off into outer space, leaving behind its core - a glowing ember the size of the Earth called a White Dwarf star. That ember will gradually cool and fade, until eventually, billions of years in the future, it will go dark.</p>
<p>The Sun’s death will be really spectacular - if you’re watching from far enough away. As the Sun’s outer layers blow away, they will form something called a “Planetary Nebula”. That nebula will only last a few tens of thousands of years - a short but beautiful farewell to our wonderful star.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171130/original/file-20170526-6377-1qyrou0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171130/original/file-20170526-6377-1qyrou0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171130/original/file-20170526-6377-1qyrou0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171130/original/file-20170526-6377-1qyrou0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171130/original/file-20170526-6377-1qyrou0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171130/original/file-20170526-6377-1qyrou0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171130/original/file-20170526-6377-1qyrou0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171130/original/file-20170526-6377-1qyrou0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Helix Nebula. The faint star at the nebula’s centre was once like the Sun. Now all that remains is a white dwarf, surrounded by an ever-expanding shroud of atmosphere, blown off into space.</span>
<span class="attribution"><span class="source">NASA, ESA, and C.R. O'Dell (Vanderbilt University)</span></span>
</figcaption>
</figure>
<p>How do we know all this? We have never watched this process happen in real time, but astronomers can see various stars at different stages of this process and are able to piece together the chain of events that way. Being an astronomer is a bit like being a detective - you have to gather clues and use them to work out what has happened (and what will happen in the future).</p>
<hr>
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<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165749/original/image-20170419-32713-1kyojyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><em>Please tell us your name, age and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.</em></p><img src="https://counter.theconversation.com/content/78029/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonti Horner does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>In five or seven billion years time, the Sun’s life will come to an end. And it will be really spectacular - if you’re watching from far enough away.Jonti Horner, Vice Chancellor's Senior Research Fellow, University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/648852017-01-01T18:33:49Z2017-01-01T18:33:49ZLook up! Your guide to some of the best meteor showers for 2017<figure><img src="https://images.theconversation.com/files/150903/original/image-20161220-26712-5rttec.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Patience can be rewarded as with this composite of the 2016 Geminids meteor shower, seen over Mt Teide volcano on the Canary Islands, off Spain</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/starryearth/30832909633/">Flickr/StarryEarth</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>After a disappointing 2016, when most of the annual major meteor showers were washed out by moonlight, 2017 looks far more promising. </p>
<p>Of the big three, the Quadrantids in January and Geminids in December are both visible in dark, moonless skies. Sadly, the Perseids in August will again be badly obscured by a waning gibbous Moon, but they are always worth watching.</p>
<p>Here we detail the predicted meteoric highlights for the coming year for the northern (N) and southern (S) hemispheres, and those visible for both (N/S). </p>
<p>New this year, for each shower we also give the maximum Zenithal Hourly Rate (ZHR): the maximum number of meteors per hour that could be seen, given absolutely ideal conditions.</p>
<p>The rates you actually observe will be lower than this value. The higher a shower’s radiant in the sky, and the darker the conditions, the closer the observed rates will get to the ZHR. </p>
<p>For this reason, if you <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754">want to see the best of a meteor shower</a>, try to find a good, dark site (far from streetlights), and give your eyes at <a href="http://www.telescope.com/Articles/Equipment/Binoculars/Seeing-in-the-Dark/pc/9/c/192/sc/195/p/99833.uts">least half an hour to adjust to the darkness</a>. </p>
<p>For each shower, the time of forecast maximum is given in Universal Time (<a href="https://www.timeanddate.com/worldclock/timezone/utc">UT</a>), with conversions to local time for certain regions where the shower could be observed. For other regions simply convert from UT into your <a href="http://earthsky.org/astronomy-essentials/universal-time">local timezone</a>.</p>
<p>The parent is the comet or asteroid responsible for the debris through which the Earth passes each year that’s the cause of the annual meteor shower.</p>
<h2>Quadrantids (N)</h2>
<h3>Active: December 28, 2016 - January 12, 2017</h3>
<h3>Forecast Maximum: January 3, 2pm UT = January 3, 6am PST (West Coast, US) = January 3, 11pm JST (Japan)</h3>
<h3>ZHR: ~120</h3>
<h3>Parent: <a href="http://cometography.com/pcomets/096p.html">Comet 96P/Machholz</a> / <a href="http://iopscience.iop.org/article/10.1086/383213/pdf">Asteroid 2003 EH1</a></h3>
<p>The Quadrantids get the new year off to a meteoric start. At their peak they can be spectacular, with rates often exceeding 100 meteors per hour. </p>
<p>For locations north of 40 degrees north, the shower’s radiant (the point on the sky from which the meteors appear) is circumpolar, which means it is always above the horizon. </p>
<p>The result? Quadrantid meteors can be seen throughout the hours of darkness. The best viewing is after midnight, local time, as the radiant climbs high into the morning sky.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/150869/original/image-20161220-26748-1jxf8y9.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/150869/original/image-20161220-26748-1jxf8y9.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/150869/original/image-20161220-26748-1jxf8y9.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/150869/original/image-20161220-26748-1jxf8y9.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/150869/original/image-20161220-26748-1jxf8y9.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/150869/original/image-20161220-26748-1jxf8y9.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/150869/original/image-20161220-26748-1jxf8y9.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/150869/original/image-20161220-26748-1jxf8y9.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Quadrantids come from the northern part of the northern hemisphere’s sky, with their radiant rising higher in the sky during the early hours of morning.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>For most of the shower’s fortnight of activity, only one or two meteors per hour might be seen. For that reason, the Quadrantids are often overlooked, but at their best, they are well worth the effort of setting an early morning alarm on a cold winter’s night.</p>
<p>The forecast maximum this year favours locations in the western part of North America and in far East Asia. Observers north of the Arctic Circle have the privilege of being able to watch the shower continuously, if they can brave the winter cold.</p>
<h2>Lyrids [N/S]</h2>
<h3>Active: April, 16-25</h3>
<h3>Forecast Maximum: April 22, 12pm UT = April 22, 5am PDT (West Coast, US) = April 22, 10pm AEST (QLD/NSW/ACT/Vic/Tas) = April 22, 8pm AWST (WA)</h3>
<h3>ZHR: 18</h3>
<h3>Parent: <a href="http://solarsystem.nasa.gov/planets/c1861g1thatcher/indepth">Comet C/1861 G1, Thatcher</a></h3>
<p>The Lyrids are a fairly consistent, moderately active meteor shower, producing around 15 to 20 meteors per hour at their peak. </p>
<p>Visible from either hemisphere, the Lyrids are best observed from northern latitudes, where the radiant climbs high in the sky before dawn. This year, the forecast peak favours observers in the Americas, although the precise timing of the maximum has been known to vary somewhat from year to year.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149490/original/image-20161210-31385-9jonla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149490/original/image-20161210-31385-9jonla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149490/original/image-20161210-31385-9jonla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149490/original/image-20161210-31385-9jonla.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149490/original/image-20161210-31385-9jonla.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149490/original/image-20161210-31385-9jonla.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149490/original/image-20161210-31385-9jonla.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149490/original/image-20161210-31385-9jonla.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">As seen from Australia, the Lyrid radiant is at its highest in the hour before sunrise.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149492/original/image-20161210-31405-1bthxc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149492/original/image-20161210-31405-1bthxc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149492/original/image-20161210-31405-1bthxc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=460&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149492/original/image-20161210-31405-1bthxc6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=460&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149492/original/image-20161210-31405-1bthxc6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=460&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149492/original/image-20161210-31405-1bthxc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=578&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149492/original/image-20161210-31405-1bthxc6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=578&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149492/original/image-20161210-31405-1bthxc6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=578&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">From America, the Lyrid radiant is high in the east before sunrise, with Venus and the crescent Moon low to the horizon and Saturn in the southern sky.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>The Lyrids have the longest recorded history of any meteor shower, with observations dating back to <a href="http://solarsystem.nasa.gov/planets/meteors/lyrids">at least 687BC</a>.</p>
<p>While the Lyrids are typically only a moderately active shower, they can occasionally be truly spectacular. Every 60 years or so, they produce rates much higher than normal, an event known as an outburst. </p>
<p>The most recent such event occurred in 1982 when, for a short time, rates topped 90 meteors per hour. In 1803 the shower was more spectacular still. Rates reached storm proportions, and the sky over the eastern states of the US was <a href="http://articles.adsabs.harvard.edu//full/1931PA.....39..256F/0000258.000.html">alight with meteors</a>, rates of more than 700 per hour.</p>
<p>This year, unfortunately, no such enhanced activity is forecast. Nevertheless, the Lyrids are still worth a look, letting us see pieces of a comet that currently lies more than a hundred billion kilometres distant.</p>
<h2>Eta Aquariids [S]</h2>
<h3>Active: April 19 - May 28</h3>
<h3>Forecast Maximum: May 6, 2am UT = May 6, 12pm AEST (QLD/NSW/ACT/Vic/Tas) = May 6, 10am AWST (WA)</h3>
<h3>ZHR: 50</h3>
<h3>Parent: <a href="http://www.ianridpath.com/halley/halley6.htm">Comet 1P/Halley</a></h3>
<p>For observers in the southern hemisphere, the Eta Aquariids are one of the highlights of the meteor calendar.</p>
<p>Active in autumn, as the nights grow ever longer, the Eta Aquariids are best observed in the hours before dawn, when rates can climb as high as 40 or 50 meteors per hour. </p>
<p>Even for locations well south of the equator, the radiant does not rise until 1am or later, so this is definitely one to set the alarm for.</p>
<p>The Eta Aquariids are the stronger of two annual showers produced when Earth passes through debris shed by <a href="http://www.ianridpath.com/halley/halley6.htm">Comet 1P/Halley</a>. We’ll come to its sister shower, the Orionids, later. </p>
<p>The debris shed by Comet Halley is spread in a wide band across Earth’s orbit, which results in the Eta Aquariids being active for a period of around six weeks. Peak rates occur for just a week or so around the forecast maximum.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149486/original/image-20161210-31364-7q73e4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149486/original/image-20161210-31364-7q73e4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149486/original/image-20161210-31364-7q73e4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=574&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149486/original/image-20161210-31364-7q73e4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=574&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149486/original/image-20161210-31364-7q73e4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=574&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149486/original/image-20161210-31364-7q73e4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=722&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149486/original/image-20161210-31364-7q73e4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=722&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149486/original/image-20161210-31364-7q73e4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=722&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In the hour before sunrise, the Eta Aquariids radiant is high in the eastern sky, with Venus and Mercury below.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Observers who brave the pre-dawn hours to observe the shower this year are in for an added treat, with Venus and Mercury putting on a spectacular show as the dawn twilight builds. </p>
<p>The Eta Aquariids themselves are fast meteors, and are often bright, continuing to make an impression as the sky brightens before dawn. </p>
<h2>The Southern Delta Aquariids, Piscis Austrinids and Alpha Capricornids [N/S; S favoured]</h2>
<h3>Active: Early-July to Mid-August</h3>
<h3>Forecast Maxima: July 28-30</h3>
<h3>Combined ZHR: 35</h3>
<h3>Parent: <a href="http://cometography.com/pcomets/096p.html">Comet 96P/Machholz</a> (Southern Delta Aquariids); Unknown (Piscis Austrinids); <a href="http://iopscience.iop.org/article/10.1088/0004-6256/139/5/1822/pdf">Comet 169P/NEAT</a> (Alpha Capricornids</h3>
<p>During late July and early August, three meteor showers combine to provide a nice spectacle for keen observers, particularly those in the southern hemisphere.</p>
<p>Given that the normally reliable and spectacular Perseids (mid August) are badly affected by moonlight this year, these showers allow observers to get their mid-year meteor fix. </p>
<p>These three showers, combined, favour observers in the southern hemisphere, though they can also be observed from northern latitudes. From both hemispheres the rates get better as the night goes on and the radiants rise, with the best rates seen in the hours after midnight. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149494/original/image-20161210-31396-18phn7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149494/original/image-20161210-31396-18phn7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149494/original/image-20161210-31396-18phn7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=533&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149494/original/image-20161210-31396-18phn7c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=533&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149494/original/image-20161210-31396-18phn7c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=533&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149494/original/image-20161210-31396-18phn7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=670&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149494/original/image-20161210-31396-18phn7c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=670&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149494/original/image-20161210-31396-18phn7c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=670&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A trio of meteor showers, as seen from the Southern Hemisphere around local midnight.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149495/original/image-20161210-31370-142mq2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149495/original/image-20161210-31370-142mq2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149495/original/image-20161210-31370-142mq2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=513&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149495/original/image-20161210-31370-142mq2y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=513&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149495/original/image-20161210-31370-142mq2y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=513&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149495/original/image-20161210-31370-142mq2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=645&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149495/original/image-20161210-31370-142mq2y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=645&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149495/original/image-20161210-31370-142mq2y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=645&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The same meteor showers, as seen from the Northern Hemisphere around local midnight.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Of the three, the Southern Delta Aquariids are the most active, with a broad peak lasting around five days, centred on July 30. Their meteors are the fastest of the three showers, as well as the most numerous. </p>
<p>The Alpha Capricornids, by contrast, are relatively slow and infrequent (just five or so per hour), but are often spectacular, with a reputation as a fireball shower. When combined with the activity from the other two showers, they represent a great opportunity for budding astro-photographers to get some spectacular shots.</p>
<h2>Orionids [N/S]</h2>
<h3>Active: October 2 - November 7</h3>
<h3>Forecast Maximum: October 21</h3>
<h3>ZHR: 20</h3>
<h3>Parent: <a href="http://www.ianridpath.com/halley/halley6.htm">Comet 1P/Halley</a></h3>
<p><a href="https://theconversation.com/see-one-of-the-years-best-meteor-showers-thanks-to-halleys-comet-33091">The Orionids</a> are the second of the annual meteor showers associated with the most famous comet, 1P/Halley.</p>
<p>In October, the Earth passes slightly farther from the densest part of Halley’s debris stream than in May, so the Orionids are somewhat weaker than their sister shower.</p>
<p>This is more than offset by the ease with which they may be observed. The Orionid radiant reaches a reasonable altitude by around midnight, local time. As a result, the shower can yield good rates for several hours before the sky starts to brighten before dawn.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149497/original/image-20161210-31364-196buvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149497/original/image-20161210-31364-196buvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149497/original/image-20161210-31364-196buvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=587&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149497/original/image-20161210-31364-196buvq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=587&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149497/original/image-20161210-31364-196buvq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=587&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149497/original/image-20161210-31364-196buvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=737&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149497/original/image-20161210-31364-196buvq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=737&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149497/original/image-20161210-31364-196buvq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=737&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Before sunrise, Orion stands upright high in the south-west as seen from the northern hemisphere.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149498/original/image-20161210-31364-1bo49ij.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149498/original/image-20161210-31364-1bo49ij.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149498/original/image-20161210-31364-1bo49ij.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=565&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149498/original/image-20161210-31364-1bo49ij.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=565&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149498/original/image-20161210-31364-1bo49ij.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=565&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149498/original/image-20161210-31364-1bo49ij.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=710&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149498/original/image-20161210-31364-1bo49ij.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=710&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149498/original/image-20161210-31364-1bo49ij.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=710&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">From the southern hemisphere, Orion appears to stand on his head, in the northern sky before dawn.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Though peak rates are forecast to occur on October 21, the Orionid maximum is usually a broad and prolonged affair. Good rates can be seen for several days before and after the maximum, with several sub-maxima occurring as Earth passes through denser filaments of debris in the broader stream. </p>
<p>Orionid rates are supplemented by meteors from the Taurid stream, a minor shower active from September until December. Where the Orionids are fast, the Taurids are very slow but they often produce spectacular fireballs.</p>
<h2>Geminids [N/S]</h2>
<h3>Active: December December 4-17</h3>
<h3>Forecast Maximum: December 14, 6:30am UT = December 14, 1:30am EST (East Coast, US) = December 14, 5:30pm AEDT (NSW/ACT/Vic/Tas) = December 14, 4:30pm AEST (QLD) = December 14, 2:30pm AWST (WA)</h3>
<h3>ZHR: 120</h3>
<h3>Parent: <a href="https://www.nasa.gov/centers/marshall/news/lunar/phaethon.html">Asteroid 3200 Phaethon</a></h3>
<p>The Geminids are probably the most <a href="https://theconversation.com/this-years-geminid-meteor-shower-will-be-a-true-spectacle-52068">reliable and rewarding of the annual meteor showers</a>. Visible from either hemisphere, they yield peak rates of well over a hundred meteors per hour. </p>
<p>Unlike some other showers, those peak rates persist for several hours (up to a day) so observers across the globe have the chance to see the shower at its best.</p>
<p>From locations well north of the equator the radiant rises just after sunset and good rates can be seen from the mid-evening onwards. </p>
<p>For the southern hemisphere the radiant rises later (mid-to-late evening). As the radiant climbs, so too will the number of meteors that can be seen.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/105015/original/image-20151209-3294-dokse.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/105015/original/image-20151209-3294-dokse.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/105015/original/image-20151209-3294-dokse.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/105015/original/image-20151209-3294-dokse.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/105015/original/image-20151209-3294-dokse.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/105015/original/image-20151209-3294-dokse.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/105015/original/image-20151209-3294-dokse.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/105015/original/image-20151209-3294-dokse.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Geminid radiant travels across the northern sky, as seen from Perth.</span>
<span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span>
</figcaption>
</figure>
<p>Geminids are moderately fast meteors, and are often bright. They also seem to persist slightly longer in the sky than meteors from other showers.</p>
<p>For southern observers, they are a fantastic summer treat to end the meteoric year, but for those north of the equator, one shower remains that can occasionally throw up an unexpected festive treat.</p>
<h2>Ursids [N only]</h2>
<h3>Active: December 17-26</h3>
<h3>Forecast Maximum: December 22, 3pm UT = December 22, 7am PST (West Coast, US) = December 22, 11pm JST (Japan)</h3>
<h3>ZHR: 10, variable</h3>
<h3>Parent: <a href="http://cometography.com/pcomets/008p.html">Comet 8P/Tuttle</a></h3>
<p>The Ursids are the final shower of the year, and are only visible for locations in the northern hemisphere. </p>
<p>Ursid meteors radiate from within just 14 degrees of the north celestial pole, so the radiant only changes in altitude by 28 degrees over the course of a night! </p>
<p>In most years, the Ursids are a fairly minor shower, yielding only ten meteors per hour at their peak for dedicated observers. But in the past they have produced at least two major outbursts, and the maximum activity seems to vary somewhat from year to year. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149489/original/image-20161210-31352-mmg7tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149489/original/image-20161210-31352-mmg7tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149489/original/image-20161210-31352-mmg7tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=516&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149489/original/image-20161210-31352-mmg7tj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=516&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149489/original/image-20161210-31352-mmg7tj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=516&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149489/original/image-20161210-31352-mmg7tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=649&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149489/original/image-20161210-31352-mmg7tj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=649&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149489/original/image-20161210-31352-mmg7tj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=649&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Ursid radiant as seen from Tokyo at 11pm, December 22.</span>
<span class="attribution"><span class="source">Museums Victoria</span></span>
</figcaption>
</figure>
<p>No major outburst is forecast for this year, but the Ursids are a shower of surprises. </p>
<p>There is the possibility that the Earth will encounter a denser clump of debris around 15 minutes ahead of the time of forecast maximum. That debris, left behind by the shower’s parent comet, 8P/Tuttle, in 884AD, will likely have become quite dispersed in the 1,133 years since it was lain down. As a result, any increase to the observed rates will probably be relatively small. </p>
<p>But it could still be well worth a look, just in case the Ursids manage to surprise us once again.</p><img src="https://counter.theconversation.com/content/64885/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>2017 is looking to be a spectacular year for meteor showers. So here’s what to look out for in both the northern and southern skies.Jonti Horner, Vice Chancellor's Senior Research Fellow, University of Southern QueenslandTanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/639362016-09-05T20:10:16Z2016-09-05T20:10:16ZExtinction alert: saving the world from a deadly asteroid impact<figure><img src="https://images.theconversation.com/files/136390/original/image-20160902-20255-p36t9x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How to save the Earth from an asteroid strike. </span> <span class="attribution"><span class="source">Shutterstock/trialhuni</span></span></figcaption></figure><p>Sixty-five million years ago, <a href="http://science.sciencemag.org/content/208/4448/1095.abstract">disaster struck</a> the Earth. An asteroid or comet around <a href="https://theconversation.com/revealed-asteroid-that-killed-the-dinosaurs-boiled-earths-atmosphere-36606">10km in diameter slammed into</a> what is now the Yucatan Peninsula in Mexico.</p>
<p>While the idea was ridiculed at first, this event is now widely believed to be the reason the dinosaurs became extinct.</p>
<p>This realisation led to a rallying of scientists and engineers around the world to detect and monitor the asteroids in the heavens, and if need be, to be prepared to deflect one from hitting us.</p>
<p>Today, we have a <a href="https://www.nasa.gov/planetarydefense/overview">Planetary Defense Coordination Office</a> under NASA whose sole mission is to prepare us for this unlikely but devastating possibility.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/B1UQHhZHeiA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>It is believed that <a href="http://www.fallingstar.com/danger.php">we have found</a> all of the asteroids the size of that which killed the dinosaurs (at least those near Earth). </p>
<h2>Recent impacts</h2>
<p>But there are many smaller asteroids that can still do a lot of damage which are undetected. In 1908, <a href="http://www.bbc.com/earth/story/20160706-in-siberia-in-1908-a-huge-explosion-came-out-of-nowhere">the Tunguska event</a> flattened about 2,000 square kilometres of forest in Siberia. </p>
<p>This asteroid was only about 50 metres across, but we have only <a href="https://b612foundation.org/faq-on-the-chelyabinsk-asteroid-impact/">found about 1%</a> of the near Earth objects (NEOs) of this size.</p>
<p>Despite being so rare, if a large asteroid did hit Earth, it would cause extraordinary damage. In fact, you’re more likely to be killed by an asteroid <a href="http://www.fallingstar.com/danger.php">than die in a shark attack</a>. </p>
<p>We know about a number of <a href="http://www.fallingstar.com/historical.php">recent asteroid impacts</a>, but we’re still discovering more in the geological record. Currently it’s estimated that NEOs which can cause global ecological effects occur around <a href="http://www.lpi.usra.edu/books/AsteroidsIII/pdf/3043.pdf">once every 500,000 years</a>.</p>
<p>Right now, despite being able to detect and track large asteroids (you can look at current known asteroid positions yourself using <a href="http://www.asteroidwhat.org/index.php">online databases</a>), we know very little about their interior.</p>
<p>Much of what we do know is based on meteorite samples which have fallen to Earth. But it is difficult to extrapolate small samples to understanding what asteroids look like as a whole.</p>
<h2>Asteroid types</h2>
<p>Asteroids have several types <a href="http://www.space.com/51-asteroids-formation-discovery-and-exploration.html">based on mineral composition</a>, but their internal structure can also potentially take <a href="http://www.swri.org/3pubs/ttoday/spring04/Cosmic.htm">several forms</a>. </p>
<p>Some might be rubble piles, weakly held together by gravity and electrostatic forces, while others might be solid bodies of rock. Different structural types would require <a href="http://www.sciencedirect.com/science/article/pii/S0032063300000489">different methods of deflection</a>. </p>
<p>For example, a rubble pile might break up if we hit it with an object, with each smaller piece still posing a threat. This might dictate a more finessed approach, such as hitting it with a <a href="http://spacegeneration.org/images/stories/Projects/NEO/winning_papers/2011-Alison%20Gibbings_MAA.pdf">smart cloud of smaller particles</a> released by a space craft.</p>
<p>The use of explosive devices to move an asteroid is expected to be about <a href="https://books.google.com.au/books?hl=en&lr=&id=Dw0A7T0fy6AC&oi=fnd&pg=PA104&ots=aJAnvB49gv&sig=tUbo9Cxn8bYTLIPxIqCh4S9Gi4Y">100 times less efficient</a> on porous asteroids compared to more solid bodies.</p>
<h2>Inside an asteroid</h2>
<p>My research involves repurposing geophysical techniques used for more than a century on Earth to determine the strength and structure of asteroids. To test whether these techniques will work requires simulating asteroid conditions in a lab. </p>
<p>This means we have to recreate the gravity, atmospheric and temperature conditions. We also have to find a material that matches the properties of an asteroid surface to test our equipment on.</p>
<p>NASA performs experiments in low gravity using a <a href="http://www.nasa.gov/centers/armstrong/features/parabolic_flights_06_15.html">parabolic jet</a>, which is temporarily in free fall. Atmospheric conditions can be modified in a <a href="http://www.nasa.gov/multimedia/imagegallery/image_feature_1281.html">vacuum chamber</a>. </p>
<p>Researchers have developed <a href="http://commons.erau.edu/cgi/viewcontent.cgi?article=1150&context=discovery-day">simulant materials</a> that are similar in chemical composition to various classes of asteroids. As well as being useful for testing mining equipment that might be used on asteroids, they can also be used to test geophysical equipment might be able to determine useful properties, such as structure.</p>
<p>Once this technology is proven, it can potentially be used to land on an asteroid and peer into its interior. By understanding its structure, porosity and strength, we can then start to plan deflection strategies for individual asteroids, and for asteroids in general.</p>
<h2>Being prepared</h2>
<p>The dinosaurs went extinct because they didn’t have a space program. Luckily, we are more prepared (although Australia is still one of just two OECD nations <a href="https://theconversation.com/lets-talk-about-the-space-industry-in-australias-election-campaign-61567">without a space program</a>, the other is Iceland).</p>
<p>If we were to detect an inbound asteroid with warning of at least several years, we can send a mission to find out what it’s made of. Then we can plan the optimal strategy complete with backup plans.</p>
<p>In 1995, a workshop with ex-Cold War US and Russian weapons designers was held to propose a way of deflecting an asteroid if it was detected at the last minute. They came up with (though never built) a nuclear weapon capable of <a href="https://e-reports-ext.llnl.gov/pdf/232015.pdf">instantly vaporising a 1km asteroid</a>.</p>
<p>It would also have the potential to move an extinction class asteroid out of our path given at least a few months notice, or a comet given two years notice. Given any less time, we may have to be content with evacuating as many people as possible from the predicted landing site.</p>
<p>Asteroid impacts aren’t the only event that might wipe us out. Nuclear warfare, biological terrorism and artificial intelligence all have the <a href="https://theconversation.com/the-five-biggest-threats-to-human-existence-27053">potential to destroy us</a>. Some researchers have even suggested that the probability of humanity surviving until 2100 <a href="https://www.theguardian.com/books/2003/jun/14/featuresreviews.guardianreview10">is just one in two</a>. </p>
<p>Given this level of risk, one thing is certain: we can and should spend more time and resources trying to reduce these risks.</p><img src="https://counter.theconversation.com/content/63936/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Dello-Iacovo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Large asteroid hits on Earth have the potential to wipe out humanity so knowing how to detect and deflect them is vital. But we know very little about the interior make up of many asteroids.Michael Dello-Iacovo, PhD candidate (Mining Engineering), UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.