tag:theconversation.com,2011:/uk/topics/cosmos-14810/articlesCosmos – The Conversation2024-01-19T01:58:47Ztag:theconversation.com,2011:article/2212232024-01-19T01:58:47Z2024-01-19T01:58:47ZJapan is about to land its first lunar probe. As more nations race to the Moon, how will we keep the peace?<figure><img src="https://images.theconversation.com/files/570001/original/file-20240118-23-zlvufg.jpg?ixlib=rb-1.1.0&rect=287%2C109%2C1342%2C968&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Illustration of the Japanese moon
lander separating in orbit.</span> <span class="attribution"><a class="source" href="https://jda.jaxa.jp/result.php?lang=e&id=99a1760a907a60514deaad8181c9a853">JAXA</a></span></figcaption></figure><p>Early on Saturday, January 20 2024, Japan hopes to become the fifth country to successfully <a href="https://global.jaxa.jp/press/2024/01/20240115-1_e.html">land a probe</a> on the Moon. To date, the United States, the Soviet Union, China and India have preceded the East Asian nation.</p>
<p>Launched in September 2023 by the Japanese Aerospace Exploration Agency (<a href="https://global.jaxa.jp/">JAXA</a>), the Japanese Smart Lander for Investigating Moon (SLIM) is set to touch down around 02:20am AEDT. Trialling a novel landing technique with pinpoint accuracy, it is poised to settle on a gently sloped crater rim – a first in lunar exploration. </p>
<p>JAXA celebrates the mission as a technology demonstrator. The agency’s main aim is to practice near-real-time visual precision landing. The newly developed landing technology would allow them to touch down anywhere they want, rather than only where the terrain is favourable. </p>
<p>Plans for a follow-up expedition, the Lunar Polar Exploration probe (<a href="https://global.jaxa.jp/activity/pr/jaxas/no092/02.html">LUPEX</a>), are well advanced. That mission <a href="https://economictimes.indiatimes.com/news/science/isro-working-on-ambitious-lunar-missions-lupex-chandrayaan-4-official/articleshow/105292411.cms">will be developed jointly</a> with the Indian Space Research Organisation (ISRO).</p>
<h2>The Moon is a busy target</h2>
<p>In recent years, the Moon has become a key target for exploration missions. For instance, just last year we witnessed Russia’s <a href="https://theconversation.com/russia-has-declared-a-new-space-race-hoping-to-join-forces-with-china-heres-why-thats-unlikely-211993">attempted landing</a> of its Luna 25 probe and the first successful ISRO Moon shot, <a href="https://www.isro.gov.in/Chandrayaan3_Details.html">Chandrayaan-3</a>. </p>
<p>Meanwhile, the US aims to return humans to the Moon through their <a href="https://www.nasa.gov/specials/artemis/">Artemis</a> programme while also supporting <a href="https://phys.org/news/2024-01-lunar-lander-years-rockets-moon.html">commercial companies</a> in their quest to reestablish a viable presence there.</p>
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Read more:
<a href="https://theconversation.com/scientists-and-space-agencies-are-shooting-for-the-moon-5-essential-reads-on-modern-lunar-missions-216808">Scientists and space agencies are shooting for the Moon -- 5 essential reads on modern lunar missions</a>
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<p>NASA and its international partners aim to eventually place a crewed space station in lunar orbit, the <a href="https://www.nasa.gov/reference/nasas-gateway-program/">Gateway Lunar Space Station</a>. </p>
<p>Simultaneously, China continues its successful, carefully planned <a href="https://en.wikipedia.org/wiki/Chinese_Lunar_Exploration_Program">Chang'e project</a>. The Asian powerhouse is working towards establishing its own <a href="https://en.wikipedia.org/wiki/International_Lunar_Research_Station">International Lunar Research Station</a>. That Chinese–Russian project is <a href="https://spacenews.com/china-russia-enter-mou-on-international-lunar-research-station/">promoted</a> as “open to all interested countries and international partners”.</p>
<h2>‘Peaceful intentions’</h2>
<p>To date, the leading spacefaring nations have gone to great lengths to publicly assure us that their intentions in space are peaceful. Yet, last year Yury Borisov of Russia’s space agency Roscosmos <a href="https://www.abc.net.au/news/2023-08-22/russia-declares-the-race-has-begun-for-moons-resources/102757808">bluntly stated</a>: </p>
<blockquote>
<p>This is not just about the prestige of the country and the achievement of some geopolitical goals. This is about ensuring defensive capabilities and achieving technological sovereignty.</p>
</blockquote>
<p>Borisov’s comments should not be read in isolation, however. US officials have made similar assertions. In July last year, the US assistant secretary of defense for space policy, John F. Plumb, was <a href="https://www.defense.gov/News/News-Stories/Article/Article/3465982/space-integral-to-the-dod-way-of-war-policy-chief-says/">equally blunt</a>:</p>
<blockquote>
<p>Space is in our DNA for the military. It’s absolutely essential to our way of war.</p>
</blockquote>
<p>Such official commentary is clearly anathema to the purported peaceful intentions expressed by officials elsewhere in their respective national hierarchies. Similarly, to safeguard its national interests and <a href="https://www.reuters.com/article/idUSBREA3E03H/">encouraged</a> by President Xi Jinping himself, China has been <a href="https://www.airuniversity.af.edu/Portals/10/SSQ/documents/Volume-06_Issue-1/Cheng.pdf">fine-tuning</a> its own military space strategy. </p>
<p>The Moon is a large target, which to date is only accessible to a small number of actors. Yet, ever since <a href="https://moon.nasa.gov/inside-and-out/composition/water-and-ices/">evidence of water was found</a> near the Moon’s south pole, much effort has focused on finding ways to land safely in the Moon’s southern hemisphere.</p>
<p>With commercial actors and national interests thrown into the mix, we ought to consider the geopolitical implications of this new space race.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570002/original/file-20240118-15-r3cidd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Foreground of a grey surface with a half lit Earth in the distance hanging in a black sky" src="https://images.theconversation.com/files/570002/original/file-20240118-15-r3cidd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570002/original/file-20240118-15-r3cidd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570002/original/file-20240118-15-r3cidd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570002/original/file-20240118-15-r3cidd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570002/original/file-20240118-15-r3cidd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570002/original/file-20240118-15-r3cidd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570002/original/file-20240118-15-r3cidd.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">An earthrise seen from the surface of the Moon in July 1969 during the Apollo 11 mission.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/image-detail/amf-as11-44-6550/">NASA</a></span>
</figcaption>
</figure>
<h2>Who keeps the peace in space?</h2>
<p>The 1967 <a href="https://www.unoosa.org/oosa/en/ourwork/spacelaw/treaties/introouterspacetreaty.html">Outer Space Treaty</a> remains the defining legal document governing strategic conduct in space.
To date, its has been ratified by 114 countries and 22 other signatories, including all major spacefaring nations.</p>
<p>However, new technological developments and the increasing presence of private space companies have prompted some to suggest that the <a href="https://ace-usa.org/blog/foreign-policy-region/space-oceans-and-polar-regions/failures-and-successes-of-the-outer-space-treaty/">treaty has become outdated</a>.</p>
<p>Therefore, the US has independently developed a new international agreement, which it says is focused on common principles, guidelines and best practices applicable to the safe exploration of the Moon and beyond: the <a href="https://www.nasa.gov/artemis-accords/">Artemis Accords</a>.</p>
<p>Thus far, 33 countries have signed the agreement, but neither Russia nor China have acceded. Given the prevailing political differences, there is currently no clear way forward to bring all parties to the same table.</p>
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<strong>
Read more:
<a href="https://theconversation.com/outer-space-rwanda-and-nigeria-sign-an-accord-for-more-responsible-exploration-why-this-matters-203202">Outer space: Rwanda and Nigeria sign an accord for more responsible exploration – why this matters</a>
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<p>Although the Moon remains uncrowded, sustained exploration, human occupation and commercial exploitation will increase the likelihood of encounters on the lunar surface (or in orbit) between competing parties, or even between nations engaged in major conflict on Earth.</p>
<p>While the Outer Space Treaty envisions peaceful use of the space environment, the proliferation of military hardware in low Earth orbit implies that any such adverse encounter might result in <a href="https://www.aph.gov.au/About_Parliament/Parliamentary_departments/Parliamentary_Library/pubs/BriefingBook47p/OngoingMilitarisationSpace">devastating consequences</a>. </p>
<p>At present, there are few safeguards to prevent wholesale conflict escalating beyond our home planet. Diplomatic efforts have been largely <a href="https://www.scientificamerican.com/article/how-do-we-prevent-war-in-space/">lacklustre</a>. </p>
<p>Despite <a href="https://www.ucsusa.org/about/news/space-force-would-trigger-arms-race">urgent recommendations</a> from across the political spectrum to practice caution and avoid escalation, the world continues on a path towards an increasingly volatile space environment. </p>
<p>Fortunately, in this highly complex environment cool heads have thus far prevailed in resolving potential conflicts in space. As a case in point, we should probably be encouraged by the sustained multilateral collaboration on the <a href="https://www.nature.com/articles/d41586-023-01558-0">International Space Station</a>, despite the parties’ radically opposite stances on Earth.</p>
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<p><em>The author gratefully acknowledges constructive criticism on an earlier draft of this article by Dr. Fabio Favata.</em></p><img src="https://counter.theconversation.com/content/221223/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard de Grijs 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>Japan’s space agency is landing its first lunar probe this week. This makes the Moon an increasingly busy target for spacefaring nations – with conflicting political stances among them.Richard de Grijs, Professor of Astrophysics, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2186042023-12-31T20:27:24Z2023-12-31T20:27:24ZWant to buy a home telescope? Tips from a professional astronomer to help you choose<figure><img src="https://images.theconversation.com/files/565384/original/file-20231213-29-dpf9ef.jpg?ixlib=rb-1.1.0&rect=671%2C363%2C4722%2C3226&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/silhouette-of-person-standing-on-a-field-under-starry-night-8495473/">Thirdman/Pexels</a></span></figcaption></figure><p>While the unaided eye or binoculars can reveal much of the night sky, a telescope reveals so much more. Seeing Saturn’s rings or the Moon’s craters with your own eyes can be an “oh wow” moment.</p>
<p>However, choosing the right telescope can be tricky. There are telescopes with lenses and telescopes with mirrors. Telescopes that are moved by hand and others that are electronically controlled. Telescopes also come in a range of sizes, with a trade-off between light-gathering power, portability and price.</p>
<p>While there’s much to consider, changes in pricing and technology mean spectacular views of the universe are more accessible than just a decade ago.</p>
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Read more:
<a href="https://theconversation.com/want-to-get-into-stargazing-a-professional-astronomer-explains-where-to-start-218921">Want to get into stargazing? A professional astronomer explains where to start</a>
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<h2>How big should the aperture be?</h2>
<p>Aperture is fundamental for telescopes. The bigger the light-collecting lens or mirror, the fainter the objects you can see. Double the aperture from 50mm diameter to 100mm diameter, and the light-collecting area quadruples. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/562252/original/file-20231128-15-sp0qw3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A circular mirror in a museum behind a glass screen" src="https://images.theconversation.com/files/562252/original/file-20231128-15-sp0qw3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/562252/original/file-20231128-15-sp0qw3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562252/original/file-20231128-15-sp0qw3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562252/original/file-20231128-15-sp0qw3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562252/original/file-20231128-15-sp0qw3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562252/original/file-20231128-15-sp0qw3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562252/original/file-20231128-15-sp0qw3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&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 bigger mirror or lens captures more light. This mirror is from one of William Herschel’s telescopes.</span>
<span class="attribution"><span class="source">Michael Brown</span></span>
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<p>The aperture also limits the level of detail you can see, <a href="https://theconversation.com/explainer-what-is-wave-particle-duality-7414">due to the diffraction</a> (interference) of light.</p>
<p>Again, bigger is better – a larger aperture telescope will produce sharper images than a smaller aperture telescope of comparable design. Earth’s turbulent atmosphere also blurs images, which can limit the detail seen when the aperture is more than 150mm.</p>
<p>Sometimes cheaper telescopes are advertised by magnification, but a small telescope with extreme magnification just makes blurry images bigger without revealing more detail. </p>
<h2>Refractor or reflector?</h2>
<p>Should you buy a telescope with a refracting lens or a reflecting mirror? It depends what you want to look at, and your budget.</p>
<p><strong>Refracting telescopes</strong></p>
<p><a href="https://en.wikipedia.org/wiki/Refracting_telescope">Refracting telescopes</a> can be good for viewing objects on Earth and in the sky. Refracting telescopes with short focal lengths (where light is brought to a focus near the lens) can be quite compact and good for low magnification views, which is great for sweeping across dark country skies.</p>
<p>However, there are catches. While 70mm aperture refracting telescopes can be quite affordable, bigger refractor telescopes are often more expensive than comparable reflecting telescopes.</p>
<p>Refracting telescopes also suffer from chromatic aberration – where different colours aren’t brought to a common focus – and this is particularly noticeable at high magnification when stars get coloured halos. This can be mitigated using complex lens designs, but that adds to the cost.</p>
<p><strong>Reflecting telescopes</strong></p>
<p><a href="https://en.wikipedia.org/wiki/Reflecting_telescope">Reflecting telescopes</a> use mirrors to focus light. These tend to be larger and don’t suffer from chromatic aberration.</p>
<p><a href="https://www.space.com/what-are-dobsonian-telescopes">Dobsonian telescopes</a> have a simple Newtonian optical design and wooden mounts, and are a very cost effective (if sometimes bulky) option for larger apertures. <a href="https://en.wikipedia.org/wiki/Schmidt%E2%80%93Cassegrain_telescope">Schmidt-Cassegrain</a> and Maksutov telescopes, which use a combination of lenses and mirrors, are more compact (a big plus), but also more complex and expensive.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562041/original/file-20231128-15-u4sl89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A white telescope on a black sand sitting on a tiled porch" src="https://images.theconversation.com/files/562041/original/file-20231128-15-u4sl89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562041/original/file-20231128-15-u4sl89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562041/original/file-20231128-15-u4sl89.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562041/original/file-20231128-15-u4sl89.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562041/original/file-20231128-15-u4sl89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562041/original/file-20231128-15-u4sl89.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562041/original/file-20231128-15-u4sl89.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">Dobsonian telescopes are an affordable option for a large aperture telescope.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/31667440@N04/45423626755">Wutthichai Charoenburi/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>How do I find things in the sky? Depends on the mount</h2>
<p>Want to look at a celestial object? You will need to point your telescope in the right direction, keep it steady, and follow the object as it moves across the sky (due to Earth’s rotation).</p>
<p>To do this, a telescope <a href="https://www.skyatnightmagazine.com/advice/a-basic-guide-to-telescope-mounts">needs a mount</a>, which is often sold with the telescope but can also be bought separately. Mounts fall into two broad categories. </p>
<p><strong>Equatorial mounts</strong> have an axis aligned with Earth’s axis, so a single motor can compensate for Earth’s rotation. These mounts were essential for taking long exposure images with telescopes prior to computers and tend to be relatively heavy.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/562061/original/file-20231128-29-ygzgy4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large black telescope on a white mount sitting in a verandah" src="https://images.theconversation.com/files/562061/original/file-20231128-29-ygzgy4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/562061/original/file-20231128-29-ygzgy4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562061/original/file-20231128-29-ygzgy4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562061/original/file-20231128-29-ygzgy4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562061/original/file-20231128-29-ygzgy4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562061/original/file-20231128-29-ygzgy4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562061/original/file-20231128-29-ygzgy4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Telescopes need mounts so they can be positioned and securely held in place.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/astro_mike/4151500835/">Mike White/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p><strong>Alt-azimuth mounts</strong> have a vertical and a horizontal axis (how a camera is mounted on a tripod, for example), and tend to be cheaper and lighter than equatorial mounts. With the advent of cheap computing, they can now be used to automatically point at and track celestial objects.</p>
<p>To point a telescope at celestial objects you can move it manually or have electronics assist you, including “goto” mounts with motors that shift the telescope for you. </p>
<p>A completely manual telescope will be cheaper than a telescope with automation, but you will need to navigate the sky yourself.</p>
<p>Electronic assistance for navigating the sky is rapidly evolving and getting cheaper. Many telescopes on the market now use GPS and a smartphone app, which simplifies the process and makes everything more portable.</p>
<h2>Do I need a finder scope?</h2>
<p>Regardless of how you point your telescope, having a 30–50mm aperture auxiliary “finder” scope can be useful for small telescopes and essential for larger telescopes. </p>
<p>Large telescopes typically view a tiny patch of the sky, which makes finding your way tricky. A finder scope with a wider view and crosshairs simplifies things. Even telescopes with goto electronics often need to be calibrated with bright stars and locating them is easier with a finder scope.</p>
<h2>What about the eyepiece?</h2>
<p>An essential part of most telescopes is the <a href="https://www.skyatnightmagazine.com/advice/skills/eyepieces-the-basics">eyepiece</a> you look through. Sometimes decent telescopes are sold with quite cheap eyepieces, but it can be relatively inexpensive to upgrade to a better one.</p>
<p>A good start is a low-magnification eyepiece for sweeping views, and a high-magnification eyepiece for planets.</p>
<p><a href="https://www.skyatnightmagazine.com/advice/what-is-a-plossl-eyepiece">Plössl eyepieces</a> are affordable and provide good views. More complex eyepieces that provide better views are also available, and far cheaper than they once were.</p>
<p>If you want to look at the Sun, you <em>must</em> get a specially designed <a href="https://www.skyatnightmagazine.com/advice/telescope-filters-beginners-guide">solar filter</a>. Never point a telescope (including the finder scope) at the Sun without filters – it can permanently damage eyes and shatter lenses.</p>
<h2>What if I want to take astro photos?</h2>
<p>Taking basic astronomical photos has become much easier with smartphones. While you can hold a phone to the telescope eyepiece for a photo of the Moon or a planet, you will get better results with an adapter that holds your phone securely in place. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562040/original/file-20231128-29-p4frq7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A zoomed in view of the Moon with one side cast in a red shadow" src="https://images.theconversation.com/files/562040/original/file-20231128-29-p4frq7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562040/original/file-20231128-29-p4frq7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=577&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562040/original/file-20231128-29-p4frq7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=577&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562040/original/file-20231128-29-p4frq7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=577&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562040/original/file-20231128-29-p4frq7.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=724&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562040/original/file-20231128-29-p4frq7.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=724&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562040/original/file-20231128-29-p4frq7.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=724&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 photo of a lunar eclipse taken with a small telescope and iPhone.</span>
<span class="attribution"><span class="source">Michael Brown</span></span>
</figcaption>
</figure>
<p>Of course, better images can be taken with astronomy-specific cameras that can take very short exposures (for planets) or very long exposures (for fainter nebulae and galaxies). For long exposures, automatic tracking of celestial objects is essential, and that adds to a telescope’s price.</p>
<p><a href="https://www.digitalcameraworld.com/buying-guides/best-smart-telescope">Smart telescopes</a> are a relatively recent addition to the market. These goto telescopes have no eyepieces and only capture images electronically. As modern detectors are more sensitive than our eyes, they can capture quite spectacular images with a relatively small portable telescope, even when there’s light pollution.</p>
<p>However, you do lose the experience of seeing the universe directly with your own eyes through the eyepiece.</p>
<h2>Try before you buy!</h2>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/562250/original/file-20231128-17-r36dan.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small telescope sitting on a simple mount on a concrete floor" src="https://images.theconversation.com/files/562250/original/file-20231128-17-r36dan.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/562250/original/file-20231128-17-r36dan.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562250/original/file-20231128-17-r36dan.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562250/original/file-20231128-17-r36dan.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562250/original/file-20231128-17-r36dan.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562250/original/file-20231128-17-r36dan.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562250/original/file-20231128-17-r36dan.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&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 second-hand bargain, like this 70mm refractor telescope, may be lurking in someone’s garage.</span>
<span class="attribution"><span class="source">Michael Brown</span></span>
</figcaption>
</figure>
<p>If there’s a local amateur astronomical society, you can sign up or attend a star party. There should be plenty of telescopes, and owners happy to wax lyrical about them.</p>
<p>A specialist shop can also give a direct experience of a telescope: its size and how it works (with limitations during daytime). For example, you may find a telescope is too bulky or technical for your needs.</p>
<p>Online shopping can save money, but may have less customer support than a local shop. You could also snap up a bargain buying second hand, and a seller may allow you to test their telescope on the Moon and planets before buying.</p>
<p>There’s a lot to take on board before buying a telescope. Aperture, size, cost and other factors need to be considered. But there are many good options out there, and with a good choice you can see some wondrous things. And perhaps have an “oh wow” moment.</p><img src="https://counter.theconversation.com/content/218604/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael J. I. Brown receives research funding from the Australian Research Council and Monash University.
</span></em></p>A telescope can reveal so much of the night sky, including Saturn’s rings and the Moon’s craters. But choosing the right telescope is a difficult decision – here’s what you need to know.Michael J. I. Brown, Associate Professor in Astronomy, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2189212023-12-28T20:38:02Z2023-12-28T20:38:02ZWant to get into stargazing? A professional astronomer explains where to start<p>There are few things more peaceful and relaxing than a night under the stars. Through the holidays, many people head <a href="https://www.lightpollutionmap.info/#zoom=3.80&lat=-28.5041&lon=129.6954&state=eyJiYXNlbWFwIjoiTGF5ZXJCaW5nUm9hZCIsIm92ZXJsYXkiOiJ3YV8yMDE1Iiwib3ZlcmxheWNvbG9yIjpmYWxzZSwib3ZlcmxheW9wYWNpdHkiOjYwLCJmZWF0dXJlc29wYWNpdHkiOjg1fQ==">away from the bright city lights</a> to go camping. They revel in the dark skies, spangled with myriad stars.</p>
<p>As a child, I loved such trips, and they helped cement my passion for the night sky, and for all things space. </p>
<p>One of my great joys as an astronomer is sharing the night sky with people. There is something wondrous about helping people stare at the cosmos through a telescope, getting their first glimpses of the universe’s many wonders. But we can also share and enjoy the night sky just with our own eyes – pointing out the constellations and the planets, or discovering <a href="https://theconversation.com/the-geminids-the-years-best-meteor-shower-is-upon-us-and-this-one-will-be-a-true-spectacle-218923">the joys of watching meteor showers</a>.</p>
<p>It is easy to be bitten by the astronomy bug, and a common question I get asked is “how can I get more into stargazing?”. Here are ways to get started in this fascinating and timeless hobby that won’t break the bank.</p>
<h2>Learning the night sky</h2>
<p>A good place to start if you’re a budding astronomer is to learn your way around the night sky. When I was young, this involved getting hold of a planisphere (a star map, <a href="https://in-the-sky.org/planisphere/index.php">you can make your own here</a>), or a <a href="https://www.amazon.com.au/Turn-Left-Orion-Hundreds-Telescope-ebook/dp/B07H4KN8G2">good reference book</a>. </p>
<p>Today, there are <a href="https://www.space.com/best-stargazing-apps">countless good apps</a> to help you find your way around the night sky. </p>
<p>A great example of such an app is <a href="https://stellarium-web.org/">Stellarium</a> – a planetarium program allowing you to view the night sky from the comfort of your room or to plan an evening’s observing ahead of schedule.</p>
<p>To memorise the night sky, you can try star hopping. Pick out a bright, famous, easy to find constellation, and use it as a guide to help you identify the constellations around it. </p>
<p>Learn one constellation per week, and within a year, you’ll be familiar with most of <a href="https://www.iau.org/public/themes/constellations/">the constellations</a> visible from your location.</p>
<p>Let’s use Orion as an example. The slider below shows images from Stellarium, with Orion riding high in the sky on a summer’s evening. I’ve added arrows to show how you can use Orion (shown in the centre of the map below) to hop around the summer sky.</p>
<p><iframe id="tc-infographic-1007" class="tc-infographic" height="400px" src="https://cdn.theconversation.com/infographics/1007/811d84689c71ac5c004a402a84a7fb446f0ae803/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>To learn the constellations around Orion, your task is relatively straightforward. Head out on a clear, dark summer’s night, and find Orion high to the north. The three stars of Orion’s belt are a fantastic signpost to Orion’s neighbours. </p>
<p>If you follow the line of the belt upwards and to the right, you come to <a href="https://en.wikipedia.org/wiki/Sirius">Sirius</a> – the brightest star in the night sky, and the brightest star in <a href="https://en.wikipedia.org/wiki/Canis_Major">Canis Major</a>, the big hunting dog. Carry the line on and curve to the left as you go, and you’ll find <a href="https://en.wikipedia.org/wiki/Canopus">Canopus</a>, the second brightest star in the sky.</p>
<p>Now come back to Orion’s belt, and follow its line down and to the left. You’ll come to a V-shaped group of stars, including the bright red <a href="https://en.wikipedia.org/wiki/Aldebaran">Aldebaran</a>. This is the <a href="https://en.wikipedia.org/wiki/Hyades_(star_cluster)">Hyades star cluster</a> (with Aldebaran a foreground interloper), which makes up the head of <a href="https://en.wikipedia.org/wiki/Taurus_(constellation)">Taurus</a>, the bull.</p>
<p>Take the line further, and you come to <a href="https://www.space.com/pleiades.html">the Pleiades</a> – often known as the Seven Sisters – a beautiful star cluster easily visible to the naked eye.</p>
<p>Back to Orion again. This time, you’re going to draw a line from <a href="https://en.wikipedia.org/wiki/Rigel">Rigel</a> (the bright star at the top-left of Orion’s boxy body) through <a href="https://en.wikipedia.org/wiki/Betelgeuse">Betelgeuse</a> (the bright red star at the lower-right of the box) and continue it towards the horizon. This takes you to <a href="https://en.wikipedia.org/wiki/Gemini_(constellation)">Gemini</a> – the twins.</p>
<p>Just by using Orion as the signpost, you can find your way to a good number of constellations (the cyan line points to <a href="https://en.wikipedia.org/wiki/Lepus_(constellation)">Lepus</a>, the hare; the white line to <a href="https://en.wikipedia.org/wiki/Canis_Minor">Canis Minor</a>, the little hunting dog). </p>
<p>By star hopping, you’ll slowly but surely learn your way around the night sky until the constellations become familiar friends.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/kindred-skies-ancient-greeks-and-aboriginal-australians-saw-constellations-in-common-74850">Kindred skies: ancient Greeks and Aboriginal Australians saw constellations in common</a>
</strong>
</em>
</p>
<hr>
<h2>Virtual observing</h2>
<p>Looking at the sky with the naked eye is a wonderful thing, but it’s also great to zoom in and see more detail.</p>
<p>What if you don’t have access to binoculars or a telescope of your own? Thankfully, software like Stellarium can give you a fantastic virtual observing experience.</p>
<p>Imagine you want to see Saturn’s rings – a spectacular sight through even a small telescope. You can easily do this with Stellarium. Find Saturn by using the search bar and click on it to bring up the planet’s info. </p>
<p>Click on the cross-hair symbol to “lock on”, then zoom in. The further you zoom in, the more you’ll see. You can even run the clock forwards or backwards to see the planet’s moons move in their orbits, or the tilt of Saturn’s rings <a href="https://theconversation.com/will-saturns-rings-really-disappear-by-2025-an-astronomer-explains-217370">changing from our viewpoint over time</a>.</p>
<p>A virtual observing session is as simple as that – just pan around the sky until you find something you want to see, and zoom in.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564091/original/file-20231207-17-qvar43.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close up of rotating Saturn" src="https://images.theconversation.com/files/564091/original/file-20231207-17-qvar43.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564091/original/file-20231207-17-qvar43.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=437&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564091/original/file-20231207-17-qvar43.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=437&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564091/original/file-20231207-17-qvar43.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=437&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564091/original/file-20231207-17-qvar43.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=549&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564091/original/file-20231207-17-qvar43.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=549&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564091/original/file-20231207-17-qvar43.gif?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">Example of using the clock feature in Stellarium to see the movement of Saturn’s moons.</span>
<span class="attribution"><span class="source">Stellarium</span></span>
</figcaption>
</figure>
<h2>A hobby best shared</h2>
<p>Now, a virtual observing session is great, but it pales compared to the real thing. I’d recommend using planetarium programs like Stellarium to figure out what you want to see, then heading out to look at it with your own eyes.</p>
<p>Astronomy is a wonderful hobby, and one that is best shared. Most towns and cities have their own astronomy clubs, and they’re usually more than happy to welcome guests who want to gaze at the night sky. </p>
<p>I joined my local astronomy society, the <a href="https://www.wyas.org.uk/">West Yorkshire Astronomical Society</a> in the United Kingdom, when I was just eight years old. I owe them so much. The members were incredibly supportive of a young kid with so many questions, and I genuinely believe I would not be where I am today without their help. As a member, I saw firsthand just how fantastic the amateur astronomy community is. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/562685/original/file-20231130-29-ogkxpc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A telescope inside a dome during daytime, with a young teen and two older men standing next to it" src="https://images.theconversation.com/files/562685/original/file-20231130-29-ogkxpc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/562685/original/file-20231130-29-ogkxpc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=438&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562685/original/file-20231130-29-ogkxpc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=438&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562685/original/file-20231130-29-ogkxpc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=438&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562685/original/file-20231130-29-ogkxpc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=550&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562685/original/file-20231130-29-ogkxpc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=550&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562685/original/file-20231130-29-ogkxpc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=550&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 author Jonti Horner at age 16, showing then Astronomer Royal of the UK, Arnold Wolfendale (right), the WYAS 18-inch telescope, hand-made by members. Also seen is the society’s then president, Ken Willoughby.</span>
<span class="attribution"><span class="source">Alan Horner, author provided</span></span>
</figcaption>
</figure>
<p>At the society, we had weekly talks on astronomy, given by the club members and visiting astronomers from local universities. We also had regular night sky viewing nights, using the society’s very own telescope – a behemoth the members had built themselves. </p>
<p>People who are passionate about their hobby love nothing more than sharing it with others. The members of astronomical societies are fantastic guides to the night sky, and they often have incredible equipment they’re more than happy to share with you.</p>
<p>Both astronomy clubs and universities often offer public night sky viewing nights, which are the perfect opportunity to peer at the sky through a telescope, with an experienced guide on hand to find the most impressive sights to share. </p>
<p>So, if you want to learn more about the night sky, reach out to your local astronomy society – it could be the start of something very special.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/want-to-buy-a-home-telescope-tips-from-a-professional-astronomer-to-help-you-choose-218604">Want to buy a home telescope? Tips from a professional astronomer to help you choose</a>
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</p>
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<p><em>If you want to find a local astronomy group, check out <a href="https://astronomy.org.au/amateur/amateur-societies/australia/">this list</a>. If you’re a member of a group that isn’t listed, please reach out to get them to update the list using the ‘Contact Us’ link.</em></p><img src="https://counter.theconversation.com/content/218921/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>People have been looking up at the stars for thousands of years. Here’s where to start if you want to learn more about the night sky – from spotting easy-to-find constellations to using the best apps.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2198132023-12-14T23:35:58Z2023-12-14T23:35:58ZThe first-ever survey on Australian attitudes towards space is out. So, what do we think?<figure><img src="https://images.theconversation.com/files/565712/original/file-20231214-19-k3ard3.jpg?ixlib=rb-1.1.0&rect=103%2C54%2C3858%2C2647&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">NASA rocket launched from the Arnhem Space Centre in NT on June 26 2022.</span> <span class="attribution"><a class="source" href="https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=14164&button=recent">NASA Wallops/Brian Bonsteel</a></span></figcaption></figure><p>If someone were to ask you how space technologies impact your daily life, or how much Australia should invest in space, would you have an immediate answer or would you wonder why these questions were even being asked? </p>
<p>Understanding what the average Australian thinks about space is essential – voters and taxpayers will only encourage governments to fund space activities if they feel it is important. </p>
<p>Yet until now there was no comprehensive survey of Australian opinions about space in the 66 years since humans launched their first satellite in 1957.</p>
<p>Our new <a href="https://www.spacegovcentre.org/post/space-in-the-australian-public-eye-in-depth-survey-reveals-national-opinions">report</a> shows what the Australian public thinks about Australia’s investment and activities in space and the results are eye opening. </p>
<h2>Space tech is everywhere</h2>
<p>You’ve probably used space technologies <a href="https://www.youtube.com/watch?v=wrwJqdN6NF0">many times today</a> without thinking about it. This includes navigation apps on your phone, <a href="https://www.gps.gov/applications/timing/">paying for your coffee</a>, <a href="http://www.bom.gov.au/australia/satellite/about_satellites.shtml">checking the weather</a>, <a href="https://en.wikipedia.org/wiki/Satellite_Internet_access">high-speed internet</a> and maybe even remote health services. </p>
<p>Data and services from satellites underpin activities vital to our national economy. Space helps farmers predict when to harvest their crops and GPS ensures ships, planes and trucks reach their destinations. </p>
<p>Information from space also lets us investigate climate change, assists in predicting bushfires and helps emergency services respond to floods. Pictures from space contribute to Indigenous land and water management and protecting cultural heritage.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/painting-with-fire-how-northern-australia-developed-one-of-the-worlds-best-bushfire-management-programs-205113">‘Painting with fire’: how northern Australia developed one of the world’s best bushfire management programs</a>
</strong>
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</p>
<hr>
<h2>What do Australians think about space?</h2>
<p>To understand what the public thinks about space today, the <a href="https://www.spacegovcentre.org/">Australian Centre for Space Governance</a> commissioned a study, co-funded by <a href="https://www.unsw.edu.au/canberra">UNSW Canberra</a>, which polled a nationally representative sample of more than 1,500 members of the Australian public. Our report is the first of its kind.</p>
<p>Our results showed the Australian community is interested in space but is unsure about what Australia does there. One third of Australians agreed space affected their everyday life and 44% were neutral. Around half of those surveyed are interested in Australian space activities but only a quarter said they were knowledgeable of global space events. </p>
<p>Similarly, the number of Australians who follow the activities of the <a href="https://www.space.gov.au/">Australian Space Agency</a>, established in 2018, was only around one fifth and an equal number had never heard of it. </p>
<p><iframe id="EdGzY" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/EdGzY/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Australia has a long history of space activities, usually in cooperation with international partners. Australia has tested rockets at Woomera in South Australia and supported US Moon landings. This included providing broadcast images to the world of the Apollo 11 Moon landing in 1969. </p>
<p>But when asked to choose from a list including tracking stations and Australian-born astronauts, more Australians remembered the 2001 comedy <a href="https://en.wikipedia.org/wiki/The_Dish">The Dish</a> than any of Australia’s historic space activities.</p>
<p>In addition, only 16% of Australians were aware of the country’s first (and only) locally launched satellite, <a href="https://www.dst.defence.gov.au/innovation/wresat-%E2%80%94-weapons-research-establishment-satellite">WRESAT</a>, lofted into orbit on an American rocket from Woomera in 1967.</p>
<h2>How much should Australia spend on space?</h2>
<p>Space has also been a vital part of the country’s <a href="https://www.ussc.edu.au/the-evolution-of-the-australia-us-defence-space-relationship">defence forces</a> and a range of <a href="https://nsc.crawford.anu.edu.au/publication/18851/australia-space-power-combining-civil-defence-and-diplomatic-efforts">government functions</a> that support Australia’s security and resilience. Around 50% of Australians felt the Australian Defence Force should prioritise space alongside other areas of defence interest. </p>
<p>Many people are aware of important applications of Earth observation satellites, like weather forecasting, mapping, disaster response and climate data. However, less than a quarter disagreed with the <a href="https://www.abc.net.au/news/2023-06-29/labor-axes-morrison-government-satellite-program/102538686">cancellation</a> of the A$1.2 billion National Space Mission for Earth Observation, a proposed ongoing Earth observation satellite program. Of those surveyed, 45% were neutral and less than a quarter felt the mission should not have been cancelled.</p>
<p>Space missions also allow us to understand the universe. If you’ve ever looked at a picture sent back from a NASA probe, it’s highly likely the image was received at the <a href="https://www.csiro.au/en/about/facilities-collections/international-facilities/cdscc">tracking station</a> just outside of Canberra, managed by CSIRO. Nearly 55% of Australians think it is important to invest in space science, even if there is no immediate social or economic benefit.</p>
<p><iframe id="qH93N" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/qH93N/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Overall, Australians are split about whether the country is spending the right amount on space. While 20% felt too little was spent on space technologies, 31% believed the amount was about right.</p>
<p>But the highest proportion, 36%, did not know. This is important, suggesting there isn’t sufficient information provided to the public. </p>
<h2>What do these results mean for Australia’s space future?</h2>
<p>Australians appear to be uncertain about the country’s space trajectory. But there were some clues about what direction the public feels Australia should take. Communication satellite technology and Earth observation were identified as the most important of the Australian Space Agency’s <a href="https://www.space.gov.au/Advancing%20Space%20Australian%20Civil%20Space%20Strategy%202019%20%E2%80%93%202028">seven priorities</a>. </p>
<p><iframe id="7X0A4" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/7X0A4/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Australians also saw building satellite capability as an important focus. But developing local launch capabilities was rated as the lowest priority, despite this often being the focus of <a href="https://theconversation.com/nasa-to-launch-3-rockets-from-northern-territory-in-boost-for-australian-space-efforts-184646">media reporting</a>.</p>
<p>Importantly, respondents saw space as a useful way to encourage study and work in the sciences. They also believed space activities should include a diverse representation of the community. </p>
<p>The clearest insight from this report is Australians are interested in space but are not very aware of what we do in space and why. This reflects longstanding national debates about government spending on space technologies. </p>
<p>There is an opportunity to address this. Clear messaging of how space services contribute to individual lives, national needs and government priorities, will help inform decision making. </p>
<p>It will also ensure those decisions align with what the public wants and values. </p>
<hr>
<p><em>Correction: This article previously stated the wrong year for the Apollo 11 Moon landing. It has now been corrected to 1969.</em></p><img src="https://counter.theconversation.com/content/219813/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tristan Moss receives funding from the Australian Research Council as part of a Discovery Early Career Researcher Award and from UNSW Canberra. He has previously been funded by the Department of Defence and as a Fulbright Scholar. </span></em></p><p class="fine-print"><em><span>Aleksandar Deejay receives funding from Geoscience Australia. He is the Executive Director of the Australian Centre for Space Governance and a research fellow at the School of Regulation and Global Governance (RegNet).</span></em></p><p class="fine-print"><em><span>Cassandra Steer receives funding from Geoscience Australia, Home Affairs, Department of Defence, and has previously received funding from DFAT, the Australian Space Agency, and the Canadian and US Departments of Defence. She is Chair of the Australian Centre for Space Governance and is affiliated with the International Institute of Space Law.</span></em></p><p class="fine-print"><em><span>Kathryn Robison Hasani is a Senior Research Fellow at the Australian Centre for Space Governance. She is affiliated with Flinders University. </span></em></p>Despite what you may think, Australia has a long history of space activities. But this is the first time the Australian public has been asked its opinions on space.Tristan Moss, Senior lecturer, UNSW SydneyAleksandar Deejay, Research fellow, Australian National UniversityCassandra Steer, Deputy Director, Institute for Space (InSpace), Australian National UniversityKathryn Robison Hasani, Senior Research Fellow, Australian Centre for Space Governance, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2114672023-09-18T21:55:08Z2023-09-18T21:55:08ZDiscovering the universe from our own backyards<figure><img src="https://images.theconversation.com/files/542371/original/file-20230809-19-r1poh9.jpg?ixlib=rb-1.1.0&rect=5%2C4%2C988%2C661&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Is there life beyond our world?</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>When I was a college student, I worked at the Charlevoix Astronomical Observatory in Québec. </p>
<p>It was a pretty decent summer job, as I got to observe celestial bodies until the dead of night, talk to astronomy buffs about space exploration and watch children be amazed by Saturn’s rings. </p>
<p>Over the dozens of astronomy nights I’ve hosted, one question has consistently come up:</p>
<p>“Does life exist anywhere else?”</p>
<p>Answering this fundamental question, articulated by the first philosophers, which has transcended time and eras and <a href="https://theconversation.com/are-we-alone-in-the-universe-4-essential-reads-on-potential-contact-with-aliens-210955">still remains at the heart of our rational thinking</a>, was a big assignment for me as a CEGEP student at the time. </p>
<p>I merely offered a simple “most likely,” before adding a surprising “and if that’s the case, the answer lies here, on Earth, in places called ‘planetary analogues.’”</p>
<p>Planetary analogues are locations on Earth that replicate one or more extreme conditions found on another celestial body. For example, temperature, pressure and solar radiation.</p>
<p>Both for technical and financial reasons, carrying out several space missions per year, manned or unmanned, is simply not realistic, especially as these missions take several years to complete.</p>
<p>Yet the Earth, our magnificent blue planet where life thrives, has some extreme, dangerous and cruel places. These places can reproduce certain conditions found in the arid deserts of Mars or the suffocating atmosphere of Venus. </p>
<p>What if these places were, in fact, habitats where life has developed?</p>
<h2>Lakes under ice</h2>
<p>For example, consider Europa, one of the moons of Jupiter, which, along with Mars, is one of the top contenders in our quest for extraterrestrial life. Its surface is covered in a dense layer of ice about ten kilometres thick, beneath which lies… an ocean. An ocean <a href="https://doi.org/10.1038/34857">of… liquid water</a>! </p>
<p>It turns out that in Antarctica, almost 400 lakes exist in similar conditions, that is to say that they lie below a permanent ice blanket, protected from everything that happens on the surface. These are known as “subglacial” lakes.</p>
<p>Such is the case of <a href="https://doi.org/10.1038/414603a">Lake Vostok</a>, the largest and deepest lake in Antarctica. It was in the 1960s that scientists first suspected the presence of a lake beneath a four-kilometre thick layer of ice. </p>
<p>This icy barrier deprives the lake of gaseous exchanges with the atmosphere or exposure to solar radiation, making it a permanently dark place that is poor in nutrients and subject to enormous pressure — not very hospitable.</p>
<p>However, the water at the surface of the lake is concentrated in oxygen, the key chemical element for living metabolism. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/542010/original/file-20230809-24-a15igl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/542010/original/file-20230809-24-a15igl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/542010/original/file-20230809-24-a15igl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1067&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542010/original/file-20230809-24-a15igl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1067&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542010/original/file-20230809-24-a15igl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1067&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542010/original/file-20230809-24-a15igl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542010/original/file-20230809-24-a15igl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542010/original/file-20230809-24-a15igl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lake Vostok (Antarctica) lies under four kilometres of ice.</span>
<span class="attribution"><span class="source">Wikimedia</span></span>
</figcaption>
</figure>
<h2>A love for extreme conditions</h2>
<p>In 2008, <a href="https://doi.org/10.1126/science.286.5447.2144">analyses of the ice covering Lake Vostok</a> revealed the presence of micro-organisms! This essentially means that life can indeed adapt to hostile environments that would otherwise be fatal for most organisms. These super-organisms, or “extremophile,” are able to tolerate these extreme conditions. </p>
<p>As a result, the waters of Lake Vostok, isolated from the Earth’s surface for millions of years, could well contain life too — an ideal planetary analogue.</p>
<p>Studying Lake Vostok, and its possible extremophile life forms, is almost like being on Jupiter’s moon Europa. And it’s almost like studying its ocean. Were Lake Vostok able to develop life, why not the ocean on Europa as well?</p>
<p>Subglacial lakes such as Vostok are just one example of the dozens of planetary analogue sites that have been identified. For example, in order to study certain Martian craters, the <a href="https://doi.org/10.1017/S1473550413000396">Earth’s deserts are the perfect playgrounds</a>. Scientists are exploring the Mojave (United States), <a href="https://doi.org/10.1038/s41467-023-36172-1">Atacama (Chile)</a> and Namib (Africa) deserts, which are dry and arid. Their soil also contains extremophiles, the study of which tells us about the development of life in hot environments where water is limited.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/542017/original/file-20230809-17-hzx8dz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Mojave desert" src="https://images.theconversation.com/files/542017/original/file-20230809-17-hzx8dz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542017/original/file-20230809-17-hzx8dz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542017/original/file-20230809-17-hzx8dz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542017/original/file-20230809-17-hzx8dz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542017/original/file-20230809-17-hzx8dz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542017/original/file-20230809-17-hzx8dz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542017/original/file-20230809-17-hzx8dz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&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 soil of the Mojave Desert contains extremophilic organisms.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Preparing for space missions on Earth</h2>
<p>As well as providing a better understanding of life and its emergence, investigating planetary analogues has another advantage: preparing and simulating space missions.</p>
<p>Just think — if we’re developing a new technology to sample a rock on Mars, it would be wise to try it out first, wouldn’t it? And not just inside NASA studios, where the parameters are controlled. We must step out and go to remote, uncomfortable regions. </p>
<p>That’s what the <a href="https://doi.org/10.1130/SPE483">Apollo astronauts of the 50s and 60s</a> did (those who aimed for the moon). They went to meteorite impact craters, volcanoes, deserts, all over the Earth, for months on end. All so they could practice their techniques with a variety of adapted tools, all slowed down by their space suits. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/542009/original/file-20230809-27-z4e7sr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/542009/original/file-20230809-27-z4e7sr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542009/original/file-20230809-27-z4e7sr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542009/original/file-20230809-27-z4e7sr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542009/original/file-20230809-27-z4e7sr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542009/original/file-20230809-27-z4e7sr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542009/original/file-20230809-27-z4e7sr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542009/original/file-20230809-27-z4e7sr.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"></a>
<figcaption>
<span class="caption">Astronauts Dave Scott (left) and Jim Irwin (right) sample rocks for a possible mission to the moon in 1971.</span>
<span class="attribution"><span class="source">(Analogs for Planetary Exploration [2011])</span></span>
</figcaption>
</figure>
<h2>It all begins on Earth</h2>
<p>Space exploration and the understanding of our solar system begin on Earth. At first glance, this idea may seem counter-intuitive, but it actually makes a lot of sense when you consider the remote, almost inaccessible and extreme environments our planet contains. </p>
<p>Astrochemistry and astrobiology have emerged in this same way, as multidisciplinary fields that equip us for our research into the evolution of Earth and life.</p>
<p>Now, if I were asked the question — “Does life exist anywhere else?” — I, still naive, but starting my PhD in the chemistry of extreme polar environments, would answer:</p>
<blockquote>
<p>Ask me again in five years!</p>
</blockquote>
<p>Joking aside, analogues have their limitations in that the conditions can never be recreated in their entirety. As a result, scientists need to be cautious in their approach and avoid jumping to hasty conclusions. </p>
<p>Life in Lake Vostok is not synonymous with life on Europa, far from it. But let’s just say that it’s an excellent first step that will guide us considerably in our future missions.</p><img src="https://counter.theconversation.com/content/211467/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Fillion ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Planetary analogues are sites on Earth that are so extreme that they replicate those of celestial bodies in our solar system.Daniel Fillion, Candidat au doctorat en océanographie, Université du Québec à Rimouski (UQAR)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2088482023-08-15T20:02:57Z2023-08-15T20:02:57ZCurious Kids: how do black holes pull in light?<figure><img src="https://images.theconversation.com/files/541440/original/file-20230807-25-zu9lzr.jpg?ixlib=rb-1.1.0&rect=68%2C85%2C5623%2C3421&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/black-hole-disk-glowing-plasma-supermassive-1720186741">Shutterstock</a></span></figcaption></figure><blockquote>
<p>How can a black hole pull in light when light isn’t a physical thing? – Will, age 8, Victoria</p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>What an excellent question, Will! I too wondered about this when I started to learn the wonders of physics.</p>
<p>To answer this, we must first explain three things: 1) what is light, 2) what is gravity, and 3) what is a black hole? </p>
<h2>1) What is light?</h2>
<p>Light is just a type of energy, travelling through space. There are many different types of light we can’t physically see, but can detect and even use. For example, ultraviolet light that comes from our Sun is why you have to wear sunscreen – so the light doesn’t hurt your skin.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541443/original/file-20230807-17-eqraxl.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A chart showing the entire electromagnetic spectrum from radio waves to gamma rays" src="https://images.theconversation.com/files/541443/original/file-20230807-17-eqraxl.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541443/original/file-20230807-17-eqraxl.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=251&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541443/original/file-20230807-17-eqraxl.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=251&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541443/original/file-20230807-17-eqraxl.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=251&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541443/original/file-20230807-17-eqraxl.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=315&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541443/original/file-20230807-17-eqraxl.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=315&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541443/original/file-20230807-17-eqraxl.jpeg?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"></a>
<figcaption>
<span class="caption">The electromagnetic spectrum includes all types of electromagnetic radiation – that is, energy. The bit in the middle with a rainbow and a sun symbol on it marks visible light.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-can-our-brains-sense-electromagnetic-waves-209267">Curious Kids: can our brains sense electromagnetic waves?</a>
</strong>
</em>
</p>
<hr>
<p>It’s important for us to remember that just because light doesn’t have mass, it still is very much a physical thing in our universe, following physical laws.</p>
<p>The neat thing is, no matter what type of light, it all follows the <em>same</em> physical laws in the universe. One rule is that light always wants to travel in a straight line through space.</p>
<p>This is where we now need to break down gravity, and what space is made of. </p>
<h2>2) What is gravity?</h2>
<p>Gravity is the force that keeps us safe here on Earth. It also keeps Earth circling around (orbiting) our Sun. But what causes gravity?</p>
<p>Many scientists in history pondered this question, and came up with all sorts of theories. But when Albert Einstein presented his theory on general relativity in 1915, we started to really understand exactly what gravity was, and how it affects our universe. </p>
<p>Einstein had mathematically worked out that we exist in something called “spacetime”. You can picture this as the fabric of our universe. Like a fabric, it can bend and stretch. I like to picture space like a trampoline. When you put something heavy (like a bowling ball) in the middle of a trampoline, the fabric underneath it bends and sinks down. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/540366/original/file-20230801-24-ijcskj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A cartoon image of a purple trampoline with a bowling ball in the middle" src="https://images.theconversation.com/files/540366/original/file-20230801-24-ijcskj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/540366/original/file-20230801-24-ijcskj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=310&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540366/original/file-20230801-24-ijcskj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=310&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540366/original/file-20230801-24-ijcskj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=310&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540366/original/file-20230801-24-ijcskj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=389&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540366/original/file-20230801-24-ijcskj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=389&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540366/original/file-20230801-24-ijcskj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=389&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 trampoline being bent by a bowling ball is not unlike spacetime being bent by something heavy. This is how gravity works.</span>
<span class="attribution"><span class="source">Sara Webb</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Now imagine a universe-sized trampoline, and we place our Sun on it. The dip in that trampoline represents the gravity of the Sun. And we can do this with every object that has mass.</p>
<p>When spacetime is bent by that mass, the lines that would normally be straight become slightly curved – you can see that in the picture below. This is most extreme around the really massive objects we call black holes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/540368/original/file-20230801-17-s9g6ur.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A chart showing a grid lightly stretched by a yellow ball, and very stretched by a black ball" src="https://images.theconversation.com/files/540368/original/file-20230801-17-s9g6ur.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/540368/original/file-20230801-17-s9g6ur.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=660&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540368/original/file-20230801-17-s9g6ur.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=660&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540368/original/file-20230801-17-s9g6ur.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=660&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540368/original/file-20230801-17-s9g6ur.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=829&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540368/original/file-20230801-17-s9g6ur.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=829&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540368/original/file-20230801-17-s9g6ur.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=829&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Spacetime bending around the Sun compared to a black hole. Note the lines that once would have been straight are bent and curved under the gravity.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Deepening_gravity_well.png">Sara Webb/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-are-planets-created-200454">Curious Kids: How are planets created?</a>
</strong>
</em>
</p>
<hr>
<h2>3) What is a black hole?</h2>
<p>Black holes are, in my opinion, one of the coolest things we’ve ever discovered in the universe. Black holes are regions of space so dense, nothing can escape.</p>
<p>They are usually formed when very large stars get too heavy and collapse (implode) on themselves. Astronomers think all the mass in the black hole is actually squished into a single point in the middle.</p>
<p>Black holes get a bad reputation for eating “anything that is near them”, which is just not true. Black holes do have a distance from their centre, which we mark as the point of no return. This is called the event horizon.</p>
<p>But farther away from this point, light and matter can circle around a black hole for a very long time. </p>
<h2>So how can a black hole pull in light?</h2>
<p>Now we’ve broken down those three key things, we can answer the great question asked by Will: how can a black hole pull in light? </p>
<p>When light is travelling near a black hole, it is still trying to travel in a straight line. As it gets closer to the black hole where spacetime is bent, the light will follow those bends.</p>
<p>When light gets <em>very close</em> to the black hole, it can be trapped circling around and around it. That’s because the fabric of spacetime is bent to the extreme. As you’ll remember, light is indeed a physical thing and is affected by spacetime.</p>
<p>Possibly my favourite part about this fact is it doesn’t just apply to black holes.</p>
<p>Anything with enough mass can make light bend around it, even our Sun. This was how scientists first confirmed Einstein’s theory of gravity <a href="https://www.discovermagazine.com/the-sciences/how-the-1919-solar-eclipse-made-einstein-the-worlds-most-famous-scientist">was likely correct in 1919</a>.</p>
<p>Something really heavy, like a whole group of galaxies clumped together, can bend space so much, it works like a magnifying glass and <a href="https://esahubble.org/wordbank/gravitational-lensing">shows zoomed-in pictures</a> of the stars behind it.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-are-gravitational-waves-190830">Curious Kids: what are gravitational waves?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/208848/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sara Webb 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 holes are known for pulling in all kinds of stuff – including light. Here’s how that actually works.Sara Webb, Postdoctoral Research Fellow, Centre for Astrophysics and Supercomputing, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2056612023-05-17T20:07:13Z2023-05-17T20:07:13ZFor the first time, astronomers have detected a radio signal from the massive explosion of a dying white dwarf<figure><img src="https://images.theconversation.com/files/526409/original/file-20230516-27-yy4ak6.jpg?ixlib=rb-1.1.0&rect=35%2C29%2C3922%2C2197&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Adam Makarenko/W. M. Keck Observatory</span>, <span class="license">Author provided</span></span></figcaption></figure><p>When stars like our Sun die, they tend to go out with a whimper and not a bang – unless they happen to be part of a binary (two) star system that could give rise to a supernova explosion.</p>
<p>Now, for the first time, astronomers have spotted the radio signature of just such an event in a galaxy more than 400 million light-years away. The finding, <a href="https://www.nature.com/articles/s41586-023-05916-w">published today in Nature</a>, holds tantalising clues as to what the companion star must have been like.</p>
<h2>An explosive star death</h2>
<p>As stars up to eight times heavier than our Sun start to run out of nuclear fuel in their core, they puff off their outer layers. This process gives rise to the colourful clouds of gas misleadingly known as <a href="https://theconversation.com/extreme-stripping-action-led-to-the-messy-birth-of-the-southern-ring-nebula-webb-image-reveals-196052">planetary nebulae</a>, and leaves behind a dense, compact hot core known as a white dwarf.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/526429/original/file-20230516-29-s0aan0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black background with many cross-hatched points of bright light" src="https://images.theconversation.com/files/526429/original/file-20230516-29-s0aan0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/526429/original/file-20230516-29-s0aan0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526429/original/file-20230516-29-s0aan0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526429/original/file-20230516-29-s0aan0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526429/original/file-20230516-29-s0aan0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526429/original/file-20230516-29-s0aan0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526429/original/file-20230516-29-s0aan0.jpeg?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">This image shows some of the oldest stars in the Milky Way – ancient white dwarfs – as imaged by NASA’s Hubble Space Telescope.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/multimedia/imagegallery/image_feature_734.html">NASA and H. Richer (University of British Columbia)</a></span>
</figcaption>
</figure>
<p>Our own Sun will undergo this transition in 5 billion years or so, then slowly cool and fade away. However, if a white dwarf somehow puts on weight, a self-destruct mechanism kicks in when it gets heavier than about 1.4 times the mass of our Sun. The subsequent thermonuclear detonation destroys the star in a distinctive kind of explosion called a <a href="https://astronomy.swin.edu.au/cosmos/T/Type+Ia+Supernova">Type Ia supernova</a>.</p>
<p>But where would the extra mass come from to fuel such a bang? </p>
<p>We used to think it could be gas being stripped off a bigger companion star in a close orbit. But stars tend to be messy eaters, spilling gas everywhere. A supernova explosion would shock any spilt gas and make it <a href="https://www.csiro.au/en/news/All/News/2023/January/Supernova-remnants-with-Parkes-and-ASKAP">glow at radio wavelengths</a>. Despite decades of searching however, not a single young Type Ia supernova has ever been detected with radio telescopes.</p>
<p>Instead, we began to think Type Ia supernovae must be pairs of white dwarfs spiralling inwards and merging together in a relatively clean fashion, leaving no gas to shock – and no radio signal. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/white-dwarf-merger-is-set-to-prove-supernova-theory-37272">White dwarf merger is set to prove supernova theory</a>
</strong>
</em>
</p>
<hr>
<h2>A rare type of supernova</h2>
<p>Supernova 2020eyj was discovered by <a href="https://fallingstar.com/home.php">a telescope in Hawai'i</a> on March 23 2020. For the first seven weeks or so it behaved in much the same way as any other Type Ia supernova.</p>
<p>But for the next five months, it stopped fading in brightness. Around the same time, <a href="https://eso.org/public/teles-instr/technology/spectroscopy/">it began to show features</a> indicating gas that was unusually rich in helium. We began to suspect Supernova 2020eyj belonged to a rare subclass of Type Ia supernovae in which the blast wave, moving at more than 10,000 kilometres per second, sweeps past gas that could only have been stripped off the outer layers of a surviving companion star.</p>
<p>To try to confirm our hunch, we decided to test if there was enough gas being shocked to produce a radio signal. As the supernova is too far north to observe with telescopes like the <a href="https://www.narrabri.atnf.csiro.au/">Australia Telescope Compact Array</a> near Narrabri, we instead used <a href="https://www.e-merlin.ac.uk/index.html">an array of radio telescopes spread across the United Kingdom</a> to observe the supernova about 20 months after the explosion.</p>
<p>To our great surprise, we had the first-ever clear detection of an “infant” Type Ia supernova at radio wavelengths, confirmed by a second observation some five months later. Could this be the “smoking gun” that not all Type Ia supernovae are caused by the merger of two white dwarfs?</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/w0tVccpYw8k?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Patience pays off</h2>
<p>One of the more remarkable properties of Type Ia supernovae is that they all seem to reach pretty much the same peak brightness. This is consistent with them all having reached a similar critical mass before exploding.</p>
<p>This very attribute allowed astronomer Brian Schmidt and colleagues to reach their <a href="https://www.nobelprize.org/prizes/physics/2011/press-release/">Nobel Prize-winning conclusion</a> in the late 1990s: that the universe’s expansion since the Big Bang is not slowing down under gravity (as everyone had expected), but is accelerating due to the effects of what we now call <a href="https://www.darkenergysurvey.org/the-des-project/science/">dark energy</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/nobel-laureate-brian-schmidts-big-ideas-for-how-australia-funds-and-uses-research-204015">Nobel laureate Brian Schmidt's big ideas for how Australia funds and uses research</a>
</strong>
</em>
</p>
<hr>
<p>So, Type Ia supernovae are important cosmic objects, and the fact we still don’t know exactly how and when these stellar explosions occur, or what makes them so consistent, has been a worry to astronomers.</p>
<p>In particular, if pairs of merging white dwarfs can range in total mass up to almost three times the mass of our Sun, why should they all release about the same amount of energy?</p>
<p>Our hypothesis (and radio confirmation) that Supernova 2020eyj occurred when enough helium gas was stripped off the companion star and onto the surface of the white dwarf to push it just over the mass limit, provides a natural explanation for this consistency. </p>
<p>The question now is why we haven’t seen this radio signal before in any other Type Ia supernova. Perhaps we tried to detect them too soon after the explosion, and gave up too easily. Or maybe not all companion stars are as helium-rich and prodigious in shedding their gaseous outer layers.</p>
<p>But as our study has shown, patience and persistence sometimes pays off in ways we never expected, allowing us to hear the dying whispers of a distant star.</p><img src="https://counter.theconversation.com/content/205661/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stuart Ryder is affiliated with not-for-profit Astronomy Australia Ltd. AAL does not sponsor or endorse any of the research activities conducted under the auspices of his Adjunct role with Macquarie University, nor does it have any active connection with any of the telescopes used in this paper.</span></em></p><p class="fine-print"><em><span>Erik Kool's research is supported through funding from the Vetenskapsrådet, the Swedish Research Council.</span></em></p>Our Sun will likely go out quietly – but not all such stars do. A new radio detection of a supernova can help us better understand these cosmic cataclysms.Stuart Ryder, Adjunct Fellow, School of Mathematical and Physical Sciences, Macquarie UniversityErik Kool, Postdoctoral Researcher in Astronomy, Stockholm UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2013772023-03-12T01:41:59Z2023-03-12T01:41:59ZAstronomers just discovered a comet that could be brighter than most stars when we see it next year. Or will it?<figure><img src="https://images.theconversation.com/files/514581/original/file-20230310-24-fiv47l.jpg?ixlib=rb-1.1.0&rect=355%2C244%2C3049%2C2031&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Comets are rarely as bright as this illustration.</span> <span class="attribution"><span class="source">IgorZh/Shutterstock</span></span></figcaption></figure><p>Hot on the heels of the disappointing <a href="https://theconversation.com/australia-is-finally-getting-a-last-chance-view-of-a-green-comet-not-seen-for-50-000-years-198867">Green Comet</a>, astronomers have just discovered a new comet with the potential to be next year’s big story – C/2023 A3 (Tsuchinshan-ATLAS). </p>
<p>Although it is still more than 18 months from its closest approach to Earth and the Sun, comet Tsuchinshan-ATLAS already has social media buzzing, with optimistic articles being written about how it could be <a href="https://www.space.com/bright-new-comet-discovered-zooming-toward-the-sun-could-outshine-the-stars-next-year">a spectacular sight</a>. What’s the full story on this new icy wanderer? </p>
<h2>Introducing comet C/2023 A3 (Tsuchinshan-ATLAS)</h2>
<p>Every year, a few dozen new comets are discovered – dirty snowballs moving on highly elongated paths around the Sun. The vast majority are far too faint to see with the unaided eye. Perhaps one comet per year will approach the edge of naked-eye visibility.</p>
<p>Occasionally, however, a much brighter comet will come along. Because comets are things of ephemeral and transient beauty, the discovery of a comet with potential always leads to excitement.</p>
<p>Comet C/2023 A3 (Tsuchinshan-ATLAS) certainly fits the bill. Discovered independently by astronomers at <a href="https://en.wikipedia.org/wiki/Purple_Mountain_Observatory">Purple Mountain Observatory in China</a> and the <a href="https://atlas.fallingstar.com/">Asteroid Terrestrical-impact Last Alert System</a>, ATLAS, the comet is currently between the orbits of Jupiter and Saturn, a billion kilometres from Earth. It is falling inwards, moving on an orbit that will bring it to within 59 million kilometres of the Sun in September 2024.</p>
<p>The fact the comet was found while it’s so far away is part of the reason for astronomers’ excitement. Although currently some 60,000 times too faint to see with the naked eye, the comet <em>is</em> bright for something so far from the Sun. And observations suggest it’s following an orbit that could allow it to become truly spectacular. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/514580/original/file-20230310-462-j31o82.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram of the solar system with a small comet visible in one of the middle rings" src="https://images.theconversation.com/files/514580/original/file-20230310-462-j31o82.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514580/original/file-20230310-462-j31o82.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=364&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514580/original/file-20230310-462-j31o82.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=364&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514580/original/file-20230310-462-j31o82.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=364&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514580/original/file-20230310-462-j31o82.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=458&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514580/original/file-20230310-462-j31o82.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=458&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514580/original/file-20230310-462-j31o82.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=458&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 location of comet Tsuchinshan-ATLAS plotted on March 10 2023.</span>
<span class="attribution"><a class="source" href="https://theskylive.com/3dsolarsystem?obj=c2023a3">TheSkyLive.com</a></span>
</figcaption>
</figure>
<h2>A recipe for comet greatness</h2>
<p>It’s all down to a combination of the comet’s path through the Solar System, and the potential size of its nucleus – the solid centre.</p>
<p>As comets swing closer to the Sun, they heat up, and their surface ices sublime (turn from a solid to a gas). Erupting from the comet’s surface, this gas carries along dust, shrouding the nucleus in what’s called a coma – a giant cloud of gas and dust. The coma is then pushed away from the Sun by solar wind, resulting in a tail (or tails) pointing directly away from the Sun.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/514616/original/file-20230310-145-aisr00.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/514616/original/file-20230310-145-aisr00.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514616/original/file-20230310-145-aisr00.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514616/original/file-20230310-145-aisr00.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514616/original/file-20230310-145-aisr00.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514616/original/file-20230310-145-aisr00.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514616/original/file-20230310-145-aisr00.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514616/original/file-20230310-145-aisr00.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&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 schematic view of a comet, not to scale, showing the comet’s nucleus (a), coma (b), and gas and dust tails (c and d). Those tails always point away from the Sun (which lies in the direction of g) no matter how the comet is moving (direction f in the figure).</span>
<span class="attribution"><span class="source">Sanu N/Wkimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The closer a comet gets to the Sun, the hotter its surface becomes, and the more active it will get. Historically, the vast majority of the brightest, most spectacular comets have followed orbits that brought them closer to the Sun than Earth’s orbit. The closer, the better, and Tsuchinshan-ATLAS certainly ticks that box.</p>
<p>In fact, this new comet seems to tick all the boxes. It appears to have a sizeable nucleus, making it brighter (bright enough to be discovered so far from the Sun). It is destined to have a very close encounter with our star. And, the kicker, it will then pass almost directly between Earth and the Sun, approaching within 70 million kilometres of us just two weeks after perihelion (the closest approach to the Sun). The closer a comet comes to Earth, the brighter it will appear to us.</p>
<p>Put that together, and you have a recipe for a comet that could shine as brightly as the brightest stars. Some forecasts are even more bullish, suggesting it could be up to a hundred times brighter still!</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meteors-seem-to-be-raining-down-on-new-zealand-but-why-are-some-bright-green-187836">Meteors seem to be raining down on New Zealand, but why are some bright green?</a>
</strong>
</em>
</p>
<hr>
<h2>The curse of prediction</h2>
<blockquote>
<p>Comets are like cats: they have tails, and they do precisely what they want
– astronomer David H. Levy.</p>
</blockquote>
<p>Predicting how newly discovered comets will behave is a dangerous game. Some may be spectacular, while others fizzle. </p>
<p>Take, for example, <a href="https://en.wikipedia.org/wiki/Comet_Kohoutek">comet Kohoutek</a>, in 1973. Like Tsuchinshan-ATLAS, Kohoutek was discovered unusually far from the Sun, moving on an orbit that swung close to our star. Cue the hype. Astronomers promised the public “<a href="https://skynews.ca/kohoutek-fiasco/">the comet of the century</a>”, predicting Kohoutek could become bright enough to see in broad daylight.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/514577/original/file-20230309-21-z4xk4w.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A blue star field with a red lower left corner and a bright streak angled towards top left" src="https://images.theconversation.com/files/514577/original/file-20230309-21-z4xk4w.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514577/original/file-20230309-21-z4xk4w.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514577/original/file-20230309-21-z4xk4w.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514577/original/file-20230309-21-z4xk4w.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514577/original/file-20230309-21-z4xk4w.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514577/original/file-20230309-21-z4xk4w.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514577/original/file-20230309-21-z4xk4w.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">Photo of the comet Kohoutek (C/1973 E1) taken by members of the lunar and planetary laboratory photographic team from the University of Arizona, at the Catalina observatory with a 35mm camera on January 11 1974.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Comet_Kohoutek#/media/File:Comet_Kohoutek_(S74-17688).jpg">NASA</a></span>
</figcaption>
</figure>
<p>But comets are like cats. Kohoutek brightened as it swung in towards the Sun, but more slowly than expected. Rather than being visible in broad daylight, it was <em>only</em> as bright as the brightest stars, and faded quickly after perihelion. It was still a good show, but far from the comet of the century. Because of the hype, many dubbed Kohoutek a spectacular disappointment.</p>
<p>It turns out Kohoutek was passing through the inner Solar System for the very first time. It had never come so close to the Sun, so its surface was rich in highly volatile ice which began to sublime when the comet was still far away. At that great distance, the comet was much brighter than other, more experienced comets – and that brightness suggested the comet would be truly spectacular.</p>
<p>As it came closer to the Sun, those volatiles were exhausted, and the comet’s final activity was less than initially predicted, making it fainter.</p>
<p>There is a very real chance Tsuchinshan-ATLAS might, like comet Kohoutek, be approaching the inner Solar System for the first time. We’re not yet sure – but if it is, it might also wind up being less spectacular than predicted.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/514602/original/file-20230310-16-5wmidx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A comet sits with its greenish head at the bottom right of the image, with its tail extending to top left. In the foreground, a bright Eta Aquariid meteor can be seen, descending nearly vertically from the middle of the frame" src="https://images.theconversation.com/files/514602/original/file-20230310-16-5wmidx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514602/original/file-20230310-16-5wmidx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514602/original/file-20230310-16-5wmidx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514602/original/file-20230310-16-5wmidx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514602/original/file-20230310-16-5wmidx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514602/original/file-20230310-16-5wmidx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514602/original/file-20230310-16-5wmidx.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">Comet C/2020 F8 (SWAN), as photographed by Jonti in early May 2020. The bright near vertical streak is an Eta Aquariid - a fragment of comet 1P/Halley burning up harmlessly in the foreground. The coma of the comet lies at the bottom right, with the tail extending up to the top left corner of the frame.</span>
<span class="attribution"><span class="source">Jonti Horner</span></span>
</figcaption>
</figure>
<h2>Where it all falls apart</h2>
<p>But it could be even worse. Comets are prone to disaster. They fragment, fall apart, and disintegrate surprisingly often. Those coming into the inner Solar System for the first time are particularly fragile. </p>
<p>A recent example of such a fragmentation was comet <a href="https://en.wikipedia.org/wiki/C/2020_F8_(SWAN)">C/2020 F8 (SWAN)</a>. When SWAN was discovered, it looked promising – likely to become a naked-eye object in May 2020. But as it approached the Sun, it suddenly brightened, then became fuzzy, and began to fade away. By the time it should have been brightest, it had all but disappeared, having fallen apart before our very eyes.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/514578/original/file-20230310-14-3ega7x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dark star field with a blue glow in the middle and a bright orange streak illuminating the centre" src="https://images.theconversation.com/files/514578/original/file-20230310-14-3ega7x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/514578/original/file-20230310-14-3ega7x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=753&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514578/original/file-20230310-14-3ega7x.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=753&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514578/original/file-20230310-14-3ega7x.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=753&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514578/original/file-20230310-14-3ega7x.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=947&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514578/original/file-20230310-14-3ega7x.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=947&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514578/original/file-20230310-14-3ega7x.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=947&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 West reached peak brightness in March 1976, as seen here. During its peak, observers reported that it was bright enough to study during full daylight.</span>
<span class="attribution"><a class="source" href="https://www.eso.org/public/images/c-west-mar1976-ps/">P. Stättmayer/ESO</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>On the flip side, fragmentation events can sometimes turn a good comet into a great one. Three years after Kohoutek came <a href="https://en.wikipedia.org/wiki/Comet_West">comet C/1975 V1 (West)</a>, and it <em>was</em> truly spectacular. </p>
<p>It passed even closer to the Sun than Tsuchinshan-ATLAS will – and was already dazzling when, at perihelion, its nucleus broke into four pieces. That fragmentation event released a huge amount of gas and dust, and the comet brightened markedly, even becoming visible in broad daylight.</p>
<h2>Will Tsuchinshan-ATLAS be worth the anticipation?</h2>
<p>We won’t know for certain whether comet Tsuchinshan-ATLAS will be a spectacle until it arrives. It could fall apart and become less bright, or it could surprise us. </p>
<p>It could brighten more than expected – which would make for an amazing sight in the morning sky in late September and early October 2024, and an even better one in the evening sky in mid-October 2024</p>
<p>We just don’t know. But we’ll get our first hints in the months to come. By <a href="http://astro.vanbuitenen.nl/comet/2023A3">tracking how the comet brightens</a> as it glides sunwards, we will get our first indications as to its true fate – so keep your fingers crossed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/comet-families-similar-to-our-own-are-found-around-another-star-32817">Comet families similar to our own are found around another star</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/201377/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>The newly discovered comet C/2023 A3 Tsuchinshan-ATLAS is anticipated to be spectacularly bright late next year. But it’s important to temper our expectations.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1988672023-02-01T03:53:38Z2023-02-01T03:53:38ZAustralia is finally getting a last-chance view of a green comet not seen for 50,000 years<figure><img src="https://images.theconversation.com/files/507467/original/file-20230131-21-7p6s4z.jpg?ixlib=rb-1.1.0&rect=32%2C9%2C2993%2C2037&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/edu_inaf/52658472905/">Alessandro Bianconi/Edu INAF/Flickr </a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Over the past few weeks, social media has been abuzz with excited posts about the green comet that is currently “<a href="https://www.gulf-insider.com/dubai-witnesses-rare-comet-whizzing-across-sky/">whizzing</a>” or “flying through the sky”. </p>
<p>Now, comets don’t so much whizz as crawl. Despite that, there is a grain of truth in the reports – along with a whole heap of hype. </p>
<p>There is a relatively bright, green comet in the sky at the moment. Sadly, despite the hyperbole, you’re unlikely to spot it with the unaided eye – unless you have great eyesight, a dark sky, and know where to look.</p>
<p>People in the Northern Hemisphere have been following the comet for weeks. Now, for us in Australia, it will finally become visible, just a few days after its closest approach to Earth. So what’s all the fuss about?</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1616933701555740672"}"></div></p>
<h2>Green and rare</h2>
<p>Comet C/2022 E3 (ZTF) is a small dirty snowball discovered in March 2022 by the automated <a href="https://www.ztf.caltech.edu/">Zwicky Transient Facility</a> (hence the name ZTF).</p>
<p>Unlike asteroids, which are made of rock, comets are icy bodies. When they approach the Sun and the temperature rises, that icy surface sublimates (changes directly from a solid to a gas). The comet thus becomes shrouded in a fuzzy “coma” of gas and dust. Radiation pressure from the Sun, along with the effects of the <a href="https://www.britannica.com/science/solar-wind">solar wind</a>, pushes the gas and dust outwards, and the comet grows a “tail”. </p>
<p>The gas released by the comet is exposed to sunlight in the vacuum of space. That radiation, particularly the ultraviolet light, <a href="https://www.britannica.com/science/color/Physical-and-chemical-causes-of-colour#ref383867">excites the gas</a>. This means the gas gets rid of the energy it absorbs by shining in specific colours. </p>
<p>Much of the work astronomers do is based on breaking the light from distant objects into its component colours, to study what they are made of. Comet tails are usually blue, but comet ZTF has a very distinct greenish hue. Green is the telltale sign the comet is emitting large amounts of <a href="https://en.wikipedia.org/wiki/Diatomic_carbon">diatomic carbon</a> and <a href="https://en.wikipedia.org/wiki/Cyanogen">cyanogen</a>, which both create a greenish glow when excited.</p>
<p>So, by looking at the comet’s colour, we can immediately learn a bit about its composition – which is pretty cool!</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/507473/original/file-20230131-24-8j38ko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dark star field with a bright green and white light on the lower-right corner, with two white streaks coming out of it in different directions" src="https://images.theconversation.com/files/507473/original/file-20230131-24-8j38ko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/507473/original/file-20230131-24-8j38ko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507473/original/file-20230131-24-8j38ko.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507473/original/file-20230131-24-8j38ko.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507473/original/file-20230131-24-8j38ko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=483&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507473/original/file-20230131-24-8j38ko.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=483&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507473/original/file-20230131-24-8j38ko.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=483&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 close-up view of Comet C/2022 E3 (ZTF) on January 27 2023, captured at Lake Sonoma in California, US. You can see both its tail and even an ‘anti-tail’, an optical illusion caused by our viewing position on Earth.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/paranoidroid/52660668683/">Moshen Chan/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Upon discovery, the comet was just inside the orbit of Jupiter. Astronomers soon realised it would come relatively close to Earth in January and February this year, just a couple of weeks after its closest approach to the Sun (perihelion, <a href="https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2022E3&view=OPC">which came on January 12</a>).</p>
<p>Comet ZTF is a “long period comet”, which means it’s moving on an extremely elongated orbit around the Sun. It originated in the Oort cloud – a vast cloud of trillions of cometary nuclei that stretches halfway to the nearest star, leftovers from planetary formation 4.5 billion years ago. Those comets are held in cold storage until something nudges them inwards.</p>
<p>The last time comet ZTF graced the inner Solar System was around 50,000 years ago. While long period comets are not uncommon, interestingly this is likely ZTF’s final swing past our star. Thanks to a quirk of celestial mechanics, it is going to leave the Solar System altogether, travelling just fast enough to escape the Sun’s gravity.</p>
<p>Our Solar System (and all other planetary systems) are continually shedding comets like dandruff – with ZTF being just one more flake to add to the interstellar snowstorm.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1620388366196817920"}"></div></p>
<h2>A perfect ringside seat</h2>
<p>Now, under normal circumstances, comet ZTF would be solely of interest to keen amateur and professional astronomers. It is actually a relatively small comet, with a nucleus likely no more than a few hundred metres across.</p>
<p>Were it not for the fact of its relatively close approach, it would never get bright enough to be noteworthy.</p>
<p>Instead, pure chance has led to the comet passing through the inner Solar System at just the right time to come close to us. Instead of a dim and distant view, our planet has a perfect ringside seat to see the comet at its finest.</p>
<h2>When and where can we see it in Australia?</h2>
<p>At 17:54 UT on February 1 (that’s in the early morning of February 2 in Australia, around 5am on the east coast, but earlier in west), comet ZTF will be just under <a href="http://astro.vanbuitenen.nl/comet/2022E3">42.5 million kilometres</a> (0.284 au) from Earth. </p>
<p>Just as expected, the comet is now at its brightest – visible to observers in the Northern Hemisphere as a faint fuzzy blob (with the naked eye, from dark skies), albeit one that is made significantly harder to spot thanks to the glare of the nearly full Moon.</p>
<p>For observers in the Southern Hemisphere, we had to wait because the comet was too far in the northern sky – essentially “above” our planet in space.</p>
<p>Fortunately, the comet is now moving southwards at a rate of around <a href="https://in-the-sky.org/ephemeris.php?ird=1&irs=1&ima=1&iob=1&objtype=3&objpl=Mercury&objtxt=C%2F2022+E3+%28ZTF%29&tz=0&startday=1&startmonth=2&startyear=2023&interval=4&rows=25">five or six degrees per day</a> for the first ten days of February. Observers in the far north (Cairns and Darwin) might catch a glimpse low in the northern sky on the evening of February 2. Those in Hobart will have to wait until February 7 or 8 before it creeps high enough above the horizon to be spotted.</p>
<p>A good resource to check when the comet will be above the horizon from your home town is the free web-based planetarium package <a href="https://stellarium-web.org/">Stellarium</a>. Go to the site, pan around to the north, and set the clock (at the bottom right) to an hour or two after sunset – then step forward day by day until ‘C/2022 E3 (ZTF)’ is visible above the northern horizon.</p>
<h2>Get your gear ready</h2>
<p>Technically, the comet is currently bright enough to see with the naked eye. Eagle-eyed northern observers have been reporting sightings without optical aid since mid-January.</p>
<p>However, the comet is <em>only just</em> visible in this way – which means you need to know exactly where to look, and to have a really dark sky. And even if you can, what you see will likely be underwhelming – a dim fuzzy blob.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1620128140050972672"}"></div></p>
<p>By the time the comet is visible in Australia, it will be dimming quite rapidly, making it harder to see from one night to the next.</p>
<p>If you’re keen to see it, your best bet is to at least get a pair of binoculars. Work out where it should be, and scan the sky slowly, looking for a fuzzy patch of light.</p>
<p>The best time to find the comet will likely be February 11, when it will be within a degree of Mars, which currently shines bright and red, high to the north in the evening sky.</p>
<p>On the night of the 11th, find Mars with your binoculars, and pan just slightly to the right – you should be able to find the comet there.</p>
<p>But the best way to view the comet will be online. Astronomers worldwide are capturing incredible images of our celestial visitor. Taken with exposures many minutes in length, these photos reveal a view far better than anything possible with the naked eye.</p><img src="https://counter.theconversation.com/content/198867/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>Skies in the Northern Hemisphere have been graced by a rare, green comet. Now, it’s our turn to look for it in Australia – but the view will be dimming rapidly.Jonti Horner, Professor (Astrophysics), University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1908302023-01-12T03:45:24Z2023-01-12T03:45:24ZCurious Kids: what are gravitational waves?<figure><img src="https://images.theconversation.com/files/486718/original/file-20220927-20-rw1bvt.jpg?ixlib=rb-1.1.0&rect=17%2C224%2C1979%2C1568&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">3D visualisation of gravitational waves produced by two orbiting black holes.</span> <span class="attribution"><span class="source">Henze/NASA</span></span></figcaption></figure><blockquote>
<p>What are gravitational waves? – Millie, age 10, Sydney</p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>What a great question Millie! </p>
<p>To answer this we have to travel back in time, to the year 1916. This is the year famous physicist Albert Einstein published his general theory of relativity.</p>
<p>Einstein had figured out how to explain gravity within the Universe using maths. Gravity is the force that keeps us on Earth, and Earth orbiting around the Sun. Until 1916 there had been many theories to try and explain what gravity was and why it exists. But Einstein suggested that gravity was the bending of something called space-time. </p>
<p>You can think of space-time like the fabric of the Universe. It’s what makes up the space we live in. Without it we wouldn’t have a Universe, and that wouldn’t be very fun.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-is-it-possible-to-see-what-is-happening-in-distant-solar-systems-now-185463">Curious Kids: is it possible to see what is happening in distant solar systems now?</a>
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<h2>A space-time trampoline</h2>
<p>Curved space-time is responsible for the effects of gravity. A trampoline is a great way for us to picture this on a flat surface. </p>
<p>Imagine you place a heavy bowling ball in the centre of a trampoline – its mass bends the fabric, and it creates a dip. Now, if we tried to roll a marble across the trampoline, it would roll inwards and around the bowling ball.</p>
<p>That’s all gravity is: the distortion of the space-time fabric, affecting how things move.</p>
<figure class="align-center ">
<img alt="Top: trampoline with bowling ball bending the fabric. Bottom: trampoline with bowling ball bending the fabric, and marble path direction outlined by red arrow." src="https://images.theconversation.com/files/485636/original/file-20220920-23-pg5fnk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/485636/original/file-20220920-23-pg5fnk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=618&fit=crop&dpr=1 600w, https://images.theconversation.com/files/485636/original/file-20220920-23-pg5fnk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=618&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/485636/original/file-20220920-23-pg5fnk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=618&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/485636/original/file-20220920-23-pg5fnk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=776&fit=crop&dpr=1 754w, https://images.theconversation.com/files/485636/original/file-20220920-23-pg5fnk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=776&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/485636/original/file-20220920-23-pg5fnk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=776&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">If a heavy thing like a bowling ball stretches the trampoline, a marble will roll towards it in a circle.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This is what Einstein’s famous equations helped to explain – how we can expect space-time to move under different conditions. We know that in the Universe, nothing stands still. Everything is always moving, and when objects speed up through space-time, they can create small ripples, just like a pebble in a pond.</p>
<p>These ripples are what we call gravitational waves. Our Universe is likely full of these tiny waves, like an ocean with waves moving in all different directions.</p>
<p>But unlike the ocean, gravitational waves are incredibly small and won’t be rocking Earth about. When first predicted by Einstein, he doubted if we’d ever be able to detect them because of how teeny tiny they should be.</p>
<p>I would love to know what he would think today. Not only have we detected gravitational waves, but we’ve detected 90 unique events! This is one of the biggest achievements in physics, and how they did it was nothing short of amazing.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-is-cosmic-microwave-background-radiation-185537">Curious Kids: what is cosmic microwave background radiation?</a>
</strong>
</em>
</p>
<hr>
<h2>Squeeze and stretch</h2>
<p>When a gravitational wave passes through Earth, it squeezes or stretches the whole planet in the direction it travels. If we tried to measure it with something like a ruler, the ruler would appear to be the same length because the numbers on the ruler would also be stretched or squeezed, and wouldn’t change.</p>
<p>But scientists have a trick: they can use light, because light can only travel a certain distance over a certain time. If space is stretched out, the light has to travel a little bit farther, and takes longer. Vice versa for when space in squeezed. </p>
<p>The trick to knowing if space has been squeezed or stretched is to measure it in <em>two</em> directions, and calculate the difference. Unfortunately for us it isn’t something that is easy to measure.</p>
<p>The difference in the distance we’re looking for is 1,000 times smaller then a really tiny particle called a proton. To really blow your mind, our bodies have around 10 <em>octillion</em> protons (10,000,000,000,000,000,000,000,000,000). </p>
<p>It’s an insanely small change we needed to detect, but thankfully clever scientists and engineers figured out a way to do it, and you can learn more about these detectors in the video below.</p>
<p>Gravitational waves have given us new eyes to our Universe, allowing us to “see” things like black holes and neutron stars crashing together – because we can finally detect the tiny ripples they create. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/4GbWfNHtHRg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure><img src="https://counter.theconversation.com/content/190830/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sara Webb 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>To understand this question, we need to travel back in time.Sara Webb, Postdoctoral Research Fellow, Centre for Astrophysics and Supercomputing, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1775132022-05-25T13:46:19Z2022-05-25T13:46:19ZWhat the Voyager space probes can teach humanity about immortality and legacy as they sail through space for trillions of years<figure><img src="https://images.theconversation.com/files/464877/original/file-20220523-11-z3t5y6.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C799%2C589&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists expect the Voyager spacecraft to outlive Earth by at least a trillion years.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:PIA17036_Voyager_the_Explorer.jpg#/media/File:PIA17036_Voyager_the_Explorer.jpg">NASA/JPL-CalTech</a></span></figcaption></figure><p>Voyager 1 is the farthest human-made object from Earth. After sweeping by Jupiter, Saturn, Uranus and Neptune, it is now almost <a href="https://voyager.jpl.nasa.gov/mission/status/">15 billion miles (24 billion kilometers) from Earth</a> in interstellar space. Both Voyager 1 and its twin, Voyager 2, carry little pieces of humanity in the form of their <a href="https://voyager.jpl.nasa.gov/golden-record/">Golden Records</a>. These messages in a bottle include spoken greetings in 55 languages, sounds and images from nature, an album of recordings and images from numerous cultures, and a written message of welcome from Jimmy Carter, who was U.S. president <a href="https://theconversation.com/voyager-golden-records-40-years-later-real-audience-was-always-here-on-earth-79886">when the spacecraft left Earth in 1977</a>.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/464881/original/file-20220523-23-zyjgnu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A golden colored record with 'The Sounds of Earth' written in the center." src="https://images.theconversation.com/files/464881/original/file-20220523-23-zyjgnu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/464881/original/file-20220523-23-zyjgnu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464881/original/file-20220523-23-zyjgnu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464881/original/file-20220523-23-zyjgnu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464881/original/file-20220523-23-zyjgnu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464881/original/file-20220523-23-zyjgnu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464881/original/file-20220523-23-zyjgnu.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">Each Voyager spacecraft carries a Golden Record containing two hours of sounds, music and greetings from around the world. Carl Sagan and other scientists assumed that any civilization advanced enough to detect and capture the record in space could figure out how to play it.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:The_Sounds_of_Earth_-_GPN-2000-001976.jpg">NASA/Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>The Golden Records were built to last a billion years in the environment of space, but in a recent analysis of the paths and perils these explorers may face, astronomers calculated that they <a href="https://www.space.com/predicting-voyager-golden-records-distant-future">could exist for trillions of years</a> without coming remotely close to any stars.</p>
<p>Having spent my career in the field of <a href="https://sipa.fiu.edu/people/faculty/religious-studies/hurchingson.james.html">religion and science</a>, I’ve thought a lot about how spiritual ideas intersect with technological achievements. The incredible longevity of the Voyager spacecraft presents a uniquely tangible entry point into exploring ideas of immortality.</p>
<p>For many people, immortality is the everlasting existence of a soul or spirit that follows death. It can also mean the continuation of one’s legacy in memory and records. With its Golden Record, each Voyager provides such a legacy, but only if it is discovered and appreciated by an alien civilization in the distant future. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/464879/original/file-20220523-15-ck32f0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People in black standing around a coffin at a gravesite." src="https://images.theconversation.com/files/464879/original/file-20220523-15-ck32f0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464879/original/file-20220523-15-ck32f0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464879/original/file-20220523-15-ck32f0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464879/original/file-20220523-15-ck32f0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464879/original/file-20220523-15-ck32f0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464879/original/file-20220523-15-ck32f0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464879/original/file-20220523-15-ck32f0.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">Many religions espouse some form of life after death.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/outdoor-shot-of-funeral-royalty-free-image/104305070?adppopup=true">RubberBall Productions/Brand X Pictures via Getty Images</a></span>
</figcaption>
</figure>
<h2>Life after death</h2>
<p>Religious beliefs about immortality are numerous and diverse. Most religions foresee a postmortem career for a personal soul or spirit, and these range from everlasting residence among the stars to reincarnation. </p>
<p>The ideal eternal life for many Christians and Muslims is to abide forever in God’s presence in heaven or paradise. Judaism’s teachings about what happens after death are less clear. In the Hebrew Bible, the dead are mere “shades” in a darkened place called Sheol. Some rabbinical authorities <a href="https://jewishencyclopedia.com/articles/12697-resurrection">give credence to the resurrection of the righteous</a> and even to the eternal status of souls.</p>
<p>Immortality is not limited to the individual. It can be collective as well. For many Jews, the <a href="https://library.yctorah.org/2016/05/the-importance-of-the-land-of-israel/">final destiny of the nation of Israel or its people</a> is of paramount importance. Many Christians anticipate a <a href="https://www.britannica.com/topic/Kingdom-of-God">future general resurrection</a> of all who have died and the coming of the kingdom of God for the faithful.</p>
<p>Jimmy Carter, whose message and autograph are immortalized in the Golden Records, is a progressive Southern Baptist and a living example of religious hope for immortality. Now <a href="https://healthcare.utah.edu/healthfeed/postings/2015/08/082015_jimmy.carter.php">battling brain cancer</a> and approaching centenarian status, he has thought about dying. Following his diagnosis, Carter <a href="https://www.washingtonpost.com/politics/2019/11/04/jimmy-carter-says-he-is-completely-ease-with-death/">concluded in a sermon</a>: “It didn’t matter to me whether I died or lived. … My Christian faith includes complete confidence in life after death. So I’m going to live again after I die.”</p>
<p>It is plausible to conclude that the potential of an alien witnessing the Golden Record and becoming aware of Carter’s identity billions of years in the future would offer only marginal additional consolation for him. Carter’s knowledge in his ultimate destiny is a measure of his deep faith in the immortality of his soul. In this sense, he likely represents people of numerous faiths. </p>
<h2>Secular immortality</h2>
<p>For people who are secular or nonreligious there is little solace to be found in an appeal to the continuing existence of a soul or spirit following one’s death. Carl Sagan, who came up with the idea for the Golden Records and led their development, wrote of the afterlife: “<a href="https://www.goodreads.com/quotes/1221453-i-would-love-to-believe-that-when-i-die-i">I know of nothing to suggest that it is more than just wishful thinking</a>.” He was more saddened by thoughts of missing important life experiences – like seeing his children grow up – than fearful about the expected annihilation of his conscious self with the death of his brain.</p>
<p>For those like Sagan there are other possible options for immortality. They include <a href="https://gizmodo.com/why-freezing-yourself-is-a-terrible-way-to-achieve-immo-1552142674">freezing and preserving the body for future physical resurrection</a> or <a href="https://www.wsj.com/articles/will-your-uploaded-mind-still-be-you-11568386410">uploading one’s consciousness and turning it into a digital form</a> that would long outlast the brain. Neither of these potential paths to physical immortality has proved to be feasible yet.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/cEzcFXRKHUw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Golden Records contain a snapshot of Earth and humanity.</span></figcaption>
</figure>
<h2>The Voyagers and legacy</h2>
<p>Most people, whether secular or religious, want the actions they do while alive to bear <a href="https://doi.org/10.1016/j.jaging.2004.08.002">continuing meaning into the future as their fruitful legacy</a>. People want to be remembered and appreciated, even cherished. Sagan summed it up nicely: “To live in the hearts we leave behind <a href="https://www.goodreads.com/quotes/1029590-to-live-in-the-hearts-we-leave-behind-is-to">is to live forever</a>.” </p>
<p>With Voyagers 1 and 2 estimated to exist for more than a trillion years, they are about as immortal as it gets for human artifacts. Even before the Sun’s expected demise when it runs out of fuel in about 5 billion years, all living species, mountains, seas and forests <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">will have long been obliterated</a>. It will be as if we and all the marvelous and extravagant beauty of planet Earth never existed – a devastating thought to me.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/464878/original/file-20220523-21-ofwph8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A chart showing the path of Voyager 1 spiraling off into the distance." src="https://images.theconversation.com/files/464878/original/file-20220523-21-ofwph8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464878/original/file-20220523-21-ofwph8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=199&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464878/original/file-20220523-21-ofwph8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=199&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464878/original/file-20220523-21-ofwph8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=199&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464878/original/file-20220523-21-ofwph8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=250&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464878/original/file-20220523-21-ofwph8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=250&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464878/original/file-20220523-21-ofwph8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=250&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Voyager 1’s path, in white, has taken the craft well past the orbits of the outer planets into interstellar space, where aliens may someday come across the relic of humanity.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Voyager_1_skypath_1977-2030.png#/media/File:Voyager_1_skypath_1977-2030.png">NASA/JPL via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>But in the distant future, the two Voyager spacecraft will still be floating in space, awaiting discovery by an advanced alien civilization for whom the messages on the Golden Records were intended. Only those records will likely remain as testimony and legacy of Earth, a kind of objective immortality.</p>
<p>Religious and spiritual people can find solace in the belief that God or an afterlife waits for them after death. For the secular, hoping that someone or something will remember humanity, any wakeful and appreciative aliens will have to do.</p><img src="https://counter.theconversation.com/content/177513/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Edward Huchingson does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A professor of religion and science explains different views on immortality, from the religious perspective of President Jimmy Carter to the scientific, secular take of Carl Sagan.James Edward Huchingson, Professor Emeritus and Lecturer in Religion and Science, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1597752021-05-10T18:51:22Z2021-05-10T18:51:22ZCOVID-19 upended Americans’ sense of individualism and invited us to embrace interconnectedness – an idea from Greek philosopher Epicurus<figure><img src="https://images.theconversation.com/files/398390/original/file-20210503-17-1yk8eaz.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3994%2C2682&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nothing demonstrates our reliance on each other like a highly contagious disease.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/jeymy-mendoza-hugs-her-mother-maria-jimenez-as-they-wait-in-news-photo/1232461504">Al Seib/Los Angeles Times via Getty Images</a></span></figcaption></figure><p>The ability to <a href="https://www.huffpost.com/entry/pull-yourself-up-by-your-bootstraps-nonsense_n_5b1ed024e4b0bbb7a0e037d4">lift oneself up by their own bootstraps</a> has long been <a href="https://www.vox.com/science-and-health/2018/9/4/17759590/happiness-fantasy-capitalism-culture-carl-cederstrom">celebrated in the United States</a>. This admiration of self-reliance derives from the 17th-century English philosopher John Locke, who argued that <a href="https://plato.stanford.edu/entries/locke-political/">individuals are fully accountable for themselves because they alone own their bodies</a> – a kind of “self-ownership.”</p>
<p>Locke’s theory of self-ownership continues to inform how individuals in modern societies perceive themselves as capable of choosing and acting freely and independently, motivated by their own intentions. </p>
<p>However, <a href="https://scholar.google.com/citations?user=6GBSQXoAAAAJ&hl=en&oi=ao">as a scholar of 18th-century British literature and culture</a>, I am aware that some of Locke’s contemporaries challenged his portrayal of the fixed and ownable self, arguing that individuals are made up of constantly moving atoms and therefore fluid and prone to being transformed.</p>
<p>This idea, which came from the ancient Greek philosopher Epicurus, may prove valuable and persuasive as societies struggle to recover from the devastation of COVID-19. </p>
<h2>Origins of self-reliance</h2>
<p>John Locke presented his view of self-ownership in his “<a href="https://www.gutenberg.org/files/7370/7370-h/7370-h.htm">Second Treatise of Government</a>.” The treatise, published in 1689, was highly influential not only in England but also in the U.S. </p>
<p>The Founding Fathers adopted Locke’s portrayal of “life, liberty and property” as universal, inalienable rights, and his claim that government must attain the consent of the governed. These principles would, in 1776, <a href="https://www.ushistory.org/gov/2.asp">inform the Declaration of Independence</a>.</p>
<p>In a chapter on property, Locke asserts that “every man has a property in his own person, [which] nobody has any right to but himself.” This serves as the foundation for all personal rights within his political philosophy.</p>
<p>Confronted by the COVID-19 pandemic, though, individuals have been forced to reckon with the fragility of their self-ownership. How can one presume to have a property in their own person if the boundaries of this property are so readily breached by a deadly virus?</p>
<h2>Modern Epicureans</h2>
<p>Epicurus offered an unflinching theory of the cosmos that not only maintained that all existence is made up of atoms but also denied divine presence and insisted on death as the end of the self. The 17th and 18th centuries saw his ideas return in what has been called “The Epicurean Revival.” This revival was fueled in part by the new popularity of the ancient Roman philosopher Lucretius’ book-length poem, “<a href="https://plato.stanford.edu/entries/lucretius/">On the Nature of Things</a>,” from the first century B.C.</p>
<p>Lucretius presents <a href="https://plato.stanford.edu/entries/epicurus/">Epicurus’ philosophy</a> – which promoted pleasure, tranquility and “the good life” – in exquisite verse, making it accessible and entertaining.</p>
<p>A contributor to the Epicurean revival, the poet and devout Calvinist <a href="https://earlymodern.web.ox.ac.uk/works-lucy-hutchinson">Lucy Hutchinson</a>, produced the first <a href="https://www.oxfordscholarlyeditions.com/view/10.1093/actrade/9780199693832.book.1/actrade-9780199693832-book-1">translation of Lucretius into English</a>, and incorporated Epicurus’ theory of the atomic cosmos into her biblical epic “<a href="https://www.wiley.com/en-us/Order+and+Disorder-p-9780631220602">Order and Disorder</a>” in 1679. </p>
<p>Whereas Locke portrays the self as an object to be owned and therefore fixed, Hutchinson reveals the self to be fluid, prone to being molded and transformed by external forces such as other people or new social or environmental events. It is also porous and, with the constant movement of atoms, perpetually penetrated by the atoms of other bodies. </p>
<p>Instead of insisting on the integrity and autonomy of the self, as Locke does, Hutchinson turns her reader’s attention to the interconnectedness of selves. She portrays how, because individuals constantly undergo change, ultimately culminating in their death, they are inseparable from one another as well as from the environment.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/398406/original/file-20210503-23-1v72jun.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A Black woman wearng glasses and a green hat signs a poster." src="https://images.theconversation.com/files/398406/original/file-20210503-23-1v72jun.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/398406/original/file-20210503-23-1v72jun.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=466&fit=crop&dpr=1 600w, https://images.theconversation.com/files/398406/original/file-20210503-23-1v72jun.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=466&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/398406/original/file-20210503-23-1v72jun.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=466&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/398406/original/file-20210503-23-1v72jun.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=586&fit=crop&dpr=1 754w, https://images.theconversation.com/files/398406/original/file-20210503-23-1v72jun.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=586&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/398406/original/file-20210503-23-1v72jun.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=586&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Gwendolyn Brooks after a poetry reading in 1997.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/poet-1-bv-416-valencia-pulitzer-prize-winning-poet-news-photo/569157541">Brian Vander Brug/Los Angeles Times via Getty Images</a></span>
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<h2>‘We are each other’s business’</h2>
<p>Ironically, at the same time that the pandemic has required people to socially distance and remain within their “bubbles” or “pods,” it has also obliged individuals to recognize how profoundly connected they are to others. Nothing attests to humans’ porous nature <a href="https://read.dukeupress.edu/books/book/1261/ContagiousCultures-Carriers-and-the-Outbreak">like a highly contagious disease</a>. </p>
<p>A person’s ability to evade the virus is tied to their community’s willingness to <a href="https://theconversation.com/why-wear-face-masks-in-public-heres-what-the-research-shows-135623">wear masks</a> and <a href="https://theconversation.com/how-many-people-need-to-get-a-covid-19-vaccine-in-order-to-stop-the-coronavirus-152071">be vaccinated</a>, as well as address underlying inequities such as in <a href="https://www.nature.com/immersive/d41586-021-00943-x/index.html">housing and health care</a>. There’s also <a href="https://www.vox.com/science-and-health/22327548/covid-19-grief-bereavement-loss">new recognition</a> of how hard it is for people to pull themselves together when it feels like the world is falling apart around them. </p>
<p>[<em>Explore the intersection of faith, politics, arts and culture.</em> <a href="https://theconversation.com/us/newsletters/this-week-in-religion-76/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=religion-explore">Sign up for This Week in Religion.</a>]</p>
<p>It is likely that people will nevertheless cling to John Locke’s idea of selfhood as self-ownership, <a href="https://www.cambridge.org/core/journals/pmla/article/abs/prehistory-of-possessive-individualism/6985F24250821FF6A4D62E6F30FEE638">so fundamental it is to American democracy</a>. However, for societies to be better prepared not only to cope with future disasters but also to recover from this one, I believe a different view of the self is needed – one that takes into account just how much one’s own health depends on the health of others. </p>
<p>Like it or not, humans are atomically entangled with their environments and with one another. As the American poet <a href="https://www.poetryfoundation.org/poets/gwendolyn-brooks">Gwendolyn Brooks</a> writes in a <a href="https://poets.org/poem/paul-robeson">poem about singer, actor and activist Paul Robeson</a>, “We are each other’s harvest. We are each other’s business. We are each other’s magnitude and bond.”</p><img src="https://counter.theconversation.com/content/159775/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kristin Girten does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A British literature scholar explains how philosopher John Locke’s theory of selfhood will not help the pandemic recovery, if individuals fail to see themselves as interconnected.Kristin Girten, Associate Professor of English, University of Nebraska OmahaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1217342019-08-13T11:58:38Z2019-08-13T11:58:38ZMargaret Burbidge at 100: the trailblazing astronomer who wouldn’t take ‘no women’ for an answer<figure><img src="https://images.theconversation.com/files/287844/original/file-20190813-9400-2gxlza.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C392%2C272&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Dr. Burbidge is presented with the "Woman of the Year" award in 1976, while professor at UC San Diego.</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Margaret_Burbidge#/media/File:Margaret_burbidge.jpg">Annie Gracy/Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>As Carl Sagan famously said: “The cosmos is within us. We are made of star-stuff.” That’s not just a poetic bromide – there’s solid scientific proof that the calcium in our bones, the iron in our blood and the copper in our hair were all made in furnaces within stars. Astronomer Margaret Burbidge laid out the <a href="https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.29.547">evidence for this</a> in a 100-page paper in 1957. Her work, alongside Geoffrey Burbidge, William Fowler and Fred Hoyle, forever changed the way humans think of themselves and their place in the universe.</p>
<p>Apart from her groundbreaking work on the origin of elements, Burbidge is interested in galaxies, extremely distant and luminous cosmic objects that harbour supermassive black holes called quasars, and in the theory of a steady-state universe, an alternative to the Big Bang theory. Her life and work has influenced generations of astronomers and left an impressive legacy of discoveries. She achieved all this at a time when women often found their path to a career in science barred. </p>
<p>Burbidge recently turned 100. This is a great opportunity for generations of scientists who have been influenced by her, either personally or through her work, to <a href="http://womeninastronomy.blogspot.com/2019/08/happy-100th-birthday-margaret-burbidge.html">celebrate the life</a> of this truly stellar astronomer.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/287833/original/file-20190813-9404-8oc12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/287833/original/file-20190813-9404-8oc12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287833/original/file-20190813-9404-8oc12.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287833/original/file-20190813-9404-8oc12.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287833/original/file-20190813-9404-8oc12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287833/original/file-20190813-9404-8oc12.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287833/original/file-20190813-9404-8oc12.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">Quasars fascinated Burbidge and she spent much of her time researching them, along with other distant objects in the universe.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/scientific-astronomical-background-bright-quasar-deep-338122148?src=Mlp-DSBU5kYJhPgviOWZVw-1-4">LgorZh/Shutterstock</a></span>
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<h2>A century in science</h2>
<p>Eleanor Margaret Peachey was born on August 12 1919, in Davenport, Greater Manchester, but spent her early years in London. She first saw the starry sky at the age of four, on the boat to France with her mother. Science ran in her family – both her parents were chemists and her father had a penchant for inventing.</p>
<p>James Jeans, <a href="https://www.britannica.com/biography/James-Jeans">another prolific astronomer</a>, was also a distant relative. Although they never met, she got his popular science books as gifts for Christmas. At 12, already fascinated by big numbers, she was heavily immersed in reading them.</p>
<p>During World War II, she studied astronomy at University College London. There, she met Geoffrey Burbidge, who she married. Together, they embarked on a lifelong adventure in science. </p>
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Read more:
<a href="https://theconversation.com/you-probably-havent-heard-of-these-five-amazing-women-scientists-so-pay-attention-38329">You probably haven't heard of these five amazing women scientists – so pay attention</a>
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<p>At that time she taught a practical class with the telescope and had a chance encounter with Arthur C. Clarke, who’d later become the famous science fiction writer and futurist. Young Clarke was an enthusiastic student who <a href="https://www.aip.org/history-programs/niels-bohr-library/oral-histories/25487">wanted to learn</a> “everything to do with the planets and interplanetary travel”. Apparently he was so keen observing the stars that he almost knocked another student off the roof one night. </p>
<p>Burbidge always had a stern determination to overcome obstacles. Her <a href="https://www.skyandtelescope.com/astronomy-news/happy-birthday-margaret-burbidge/">observing logbook</a> in 1944 shows how she unflinchingly recentered the stars in the field of view of the telescope each time bombs exploding nearby jolted her eyepiece.</p>
<p>She found the strength to overcome challenges through her love of astronomy. Seeing a spiral galaxy for the first time on a photographic plate left her euphoric. She recalled:</p>
<blockquote>
<p>I felt it was almost sinful to be enjoying astronomy so much, now that it was my job and the source of my livelihood.</p>
</blockquote>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1105498374726447105"}"></div></p>
<h2>Inspiring women in science</h2>
<p>But the world was still an unkind place for gifted women scientists. Burbidge first encountered gender-based discrimination when she applied for a fellowship at the Carnegie Observatories, in the US. A letter from the director informed her curtly that such fellowships were restricted to men. Later, she was barred from observing the sky at Mount Wilson Observatory in California.</p>
<p>Burbidge wasn’t deterred and, in her usual manner, whenever she met “with a blockage,” she “found a way around it”. She gained access to Mount Wilson Observatory posing as Geoff’s assistant. She had to conceal her pregnancy while climbing up the mountain even on hot, sweltering days, swaddled in a coat.</p>
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Read more:
<a href="https://theconversation.com/nobel-prize-should-be-just-the-start-of-making-women-scientists-more-visible-104606">Nobel Prize should be just the start of making women scientists more visible</a>
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<p>She often used her professional clout to speak on behalf of other women in science. She declined the <a href="https://aas.org/grants-and-prizes/annie-jump-cannon-award-astronomy">Annie Jump Cannon award</a> in 1971 – a prize that honours the research achievements of women astronomers. She argued that gender-based awards keep women from fair recognition. This act of rebellion spurred the creation of the <a href="https://cswa.aas.org/">Committee on the Status of Women in Astronomy</a>, which encourages women into the field and promotes their work within it.</p>
<p>Today, scientists are confronted with many problems, from tackling the still-existing inequalities within their own profession, to solving all kinds of humanitarian crises. Margaret Burbidge offers a shining example of how one can achieve a breakthrough even in difficult times. While contemplating the destructive forces in the world in 1983, Margaret confessed her <a href="http://cwp.library.ucla.edu/articles/advent.html">unwavering hope for the future</a>.</p>
<blockquote>
<p>I believe we have the capacity to foresee and forestall. Scientists of all nations are in a position […] to improve the lives of all humans.</p>
</blockquote><img src="https://counter.theconversation.com/content/121734/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andreea Font has received funding from Science and Technology Facilities Council and Royal Society. </span></em></p>In an age when women were rarely allowed in observatories, Margaret Burbidge changed how we saw the stars.Andreea Font, Senior Lecturer at Astrophysics Research Institute, Liverpool John Moores UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1090972018-12-20T10:33:07Z2018-12-20T10:33:07ZIn 1968, Apollo 8 realised the 2,000-year-old dream of a Roman philosopher<figure><img src="https://images.theconversation.com/files/251565/original/file-20181219-45397-1ghvwxz.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://en.wikipedia.org/wiki/File:NASA-Apollo8-Dec24-Earthrise.jpg#/media/File:NASA-Apollo8-Dec24-Earthrise.jpg">NASA</a></span></figcaption></figure><p>Half a century of Christmases ago, the NASA space mission Apollo 8 became the first manned craft to leave low Earth orbit, atop the unprecedentedly powerful Saturn V rocket, and head out to circumnavigate another celestial body, making 11 orbits of the moon before its return. The mission is often cast in a supporting role – a sort of warm up for the first moon landing. Yet for me, the voyage of Borman, Lovell and Anders six months before Neil Armstrong’s “small step for a man” will always be the great leap for humankind.</p>
<p>Apollo 8 is the space mission for the humanities, if ever there was one: this was the moment that humanity realised a dream conceived in our cultural imagination over two millennia ago. And like that first imagined journey into space, Apollo 8 also changed our moral perspective on the world forever.</p>
<p>In the first century BC, Roman statesman and philosopher Marcus Tullius Cicero penned <a href="http://www.tertullian.org/fathers/cicero_dream_of_scipio_02_trans.htm">a fictional dream</a> attributed to the Roman general Scipio Aemilianus. The soldier is taken up into the sphere of distant stars to gaze back towards the Earth from the furthest reaches of the cosmos:</p>
<blockquote>
<p>And as I surveyed them from this point, all the other heavenly bodies appeared to be glorious and wonderful — now the stars were such as we have never seen from this earth; and such was the magnitude of them all as we have never dreamed; and the least of them all was that planet, which farthest from the heavenly sphere and nearest to our earth, was shining with borrowed light, but the spheres of the stars easily surpassed the earth in magnitude — already the earth itself appeared to me so small, that it grieved me to think of our empire, with which we cover but a point, as it were, of its surface.</p>
</blockquote>
<h2>Earth-centric</h2>
<p>Even for those of us who are familiar with the ancient and medieval Earth-centred cosmology, with its concentric celestial spheres of sun, moon, planets and finally the stars wheeling around us in splendid eternal rotation, this comes as a shock. For the diagrams that illustrate pre-modern accounts of cosmology invariably show the Earth occupying a fair fraction of the entire universe. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/251718/original/file-20181220-45397-13ubk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/251718/original/file-20181220-45397-13ubk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=443&fit=crop&dpr=1 600w, https://images.theconversation.com/files/251718/original/file-20181220-45397-13ubk8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=443&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/251718/original/file-20181220-45397-13ubk8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=443&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/251718/original/file-20181220-45397-13ubk8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=556&fit=crop&dpr=1 754w, https://images.theconversation.com/files/251718/original/file-20181220-45397-13ubk8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=556&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/251718/original/file-20181220-45397-13ubk8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=556&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The geocentric model. Bartolomeu Velho, 1568 (Bibliothèque Nationale, Paris).</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Geocentric_model#/media/File:Bartolomeu_Velho_1568.jpg">Wikimedia Commons</a></span>
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<p>Cicero’s text informs us right away that these illustrations are merely schematic, bearing as much relation to the actual imagined scale of the universe as today’s London Tube map does to the real geography of its tunnels. And his Dream of Scipio was by no means an arcane musing lost to history – becoming a major part of the canon for succeeding centuries. The fourth century Roman provincial scholar Macrobius built one of the great and compendious “commentaries” of late antiquity around it, ensuring its place in learning throughout the first millennium AD.</p>
<p>Cicero, and Macrobius after him, make two intrinsically-linked deductions. Today we would say that the first belongs to science, the second to the humanities, but, for ancient writers, knowledge was not so artificially fragmented. In Cicero’s text, Scipio first observes that the Earth recedes from this distance to a small sphere hardly distinguishable from a point. Second, he reflects that what we please to call great power is, on the scale of the cosmos, insignificant. Scipio’s companion remarks:</p>
<blockquote>
<p>I see, that you are even now regarding the abode and habitation of mankind. And if this appears to you as insignificant as it really is, you will always look up to these celestial things and you won’t worry about those of men. For what renown among men, or what glory worth the seeking, can you acquire?</p>
</blockquote>
<p>The vision of the Earth, hanging small and lowly in the vastness of space, generated an inversion of values for Cicero; a human humility. This also occurred in the case of the three astronauts of Apollo 8. </p>
<h2>A change in perspective</h2>
<p>There is a vast difference between lunar and Earth orbit – the destination of all earlier space missions. “Space” is not far away. The international space station orbits, as most manned missions, a mere 250 miles above our heads. We could drive that distance in half a day. The Earth fills half the sky from there, as it does for us on the ground.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/251566/original/file-20181219-45397-1ehsisp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/251566/original/file-20181219-45397-1ehsisp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/251566/original/file-20181219-45397-1ehsisp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=764&fit=crop&dpr=1 600w, https://images.theconversation.com/files/251566/original/file-20181219-45397-1ehsisp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=764&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/251566/original/file-20181219-45397-1ehsisp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=764&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/251566/original/file-20181219-45397-1ehsisp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=959&fit=crop&dpr=1 754w, https://images.theconversation.com/files/251566/original/file-20181219-45397-1ehsisp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=959&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/251566/original/file-20181219-45397-1ehsisp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=959&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Apollo 8 crew-members: James Lovell Jr., William Anders, Frank Borman (L-R).</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Apollo_8_Crewmembers_-_GPN-2000-001125.jpg#/media/File:Apollo_8_Crewmembers_-_GPN-2000-001125.jpg">NASA</a></span>
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<p>But the moon is 250,000 miles distant. And so Apollo 8, in one firing of the S4B third stage engine to leave Earth orbit, increased the distance from Earth attained by a human being by not one order of magnitude, but three. From the moon, the Earth is a small glistening coin of blue, white and brown in the distant black sky.</p>
<p>So it was that, as their spacecraft emerged from the far side of its satellite, and they saw the Earth slowly rise over the bleak and barren horizon, the crew grabbed all cameras to hand and shot the now iconic “Earthrise” pictures that are arguably the great cultural legacy of the Apollo program. Intoning the first verses from the Book of Genesis as their Christmas message to Earth – “… and the Earth was without form, and void, and darkness was upon the face of the deep…” – was their way of sharing the new questions that this perspective urges. As Lovell put it in <a href="https://www.space.com/42744-apollo-8-memories-james-lovell-50-years-later.html">an interview</a> this year:</p>
<blockquote>
<p>But suddenly, when you get out there and see the Earth as it really is, and when you realise that the Earth is only one of nine planets and it’s a mere speck in the Milky Way galaxy, and it’s lost to oblivion in the universe — I mean, we’re a nothing as far as the universe goes, or even our galaxy. So, you have to say, ‘Gee, how did I get here? Why am I here?’</p>
</blockquote>
<p>The 20th century realisation of Scipio’s first century BC vision also energised the early stirrings of the environmental movement. When we have seen the fragility and unique compactness of our home in the universe, we know that we have one duty of care, and just one chance.</p>
<p>Space is the destiny of our imagination, and always has been, but Earth is our precious dwelling place. Cicero’s Dream, as well as its realisation in 1968, remind the world, fresh from the Poland climate talks, that what we do with our dreams today will affect generations to come.</p><img src="https://counter.theconversation.com/content/109097/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tom McLeish receives funding from EPSRC, BBSRC, the National Formulation Centre and the Templeton World Charities Foundation. </span></em></p>Apollo 8 was the moment that humanity realised a dream conceived in our cultural imagination over two millennia ago.Tom McLeish, Professor of Natural Philosophy in the Department of Physics, University of YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/766302017-04-26T01:05:33Z2017-04-26T01:05:33ZCan Bill Nye – or any other science show – really save the world?<figure><img src="https://images.theconversation.com/files/166714/original/file-20170425-13380-14ry8qb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Will Bill Nye's new show find a wider audience than Neil deGrasse Tyson's 'Cosmos' did?</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/inVision-Vince-Bucci-Invision-AP-a-ENT-CPAENT-C-/513a1e21274242ed99d659d85630c48b/3/0">Vince Bucci/Invision for the Television Academy/AP Images</a></span></figcaption></figure><p>Netflix’s new talk show, “<a href="https://www.netflix.com/title/80117748">Bill Nye Saves the World</a>,” debuted the night before people around the world joined together to demonstrate and March for Science. Many have lauded the timing and relevance of the show, featuring the famous “<a href="https://www.netflix.com/title/80046944">Science Guy</a>” as its host, because it aims to myth-bust and debunk anti-scientific claims in an <a href="https://theconversation.com/trump-isnt-lying-hes-bullshitting-and-its-far-more-dangerous-71932">alternative-fact era</a>.</p>
<p><a href="https://theconversation.com/what-does-research-say-about-how-to-effectively-communicate-about-science-70244">But are more facts</a> really the kryptonite that will rein in what some suggest is a rapidly spreading <a href="https://www.scientificamerican.com/article/trumps-5-most-ldquo-anti-science-rdquo-moves/">“anti-science” sentiment in the U.S.</a>?</p>
<p>“With the right science and good writing,” Nye hopes, “we’ll do our best to enlighten and entertain our audience. And, <a href="https://media.netflix.com/en/press-releases/netflix-announces-new-talk-show-with-bill-nye">perhaps we’ll change the world a little</a>.” In an ideal world, a show like this might attract a broad and diverse audience with varying levels of science interest and background. By entertaining a wide range of viewers, the thinking goes, the show could effectively dismantle enduring beliefs that are at odds with scientific evidence. Significant parts of the public still aren’t on board with the <a href="https://theconversation.com/yes-we-can-do-sound-climate-science-even-though-its-projecting-the-future-75763">scientific consensus on climate change</a> and the <a href="https://theconversation.com/vaccines-back-in-the-headlines-heres-what-the-experts-say-47815">safety of vaccines</a> and <a href="https://theconversation.com/new-report-on-ge-crops-avoids-simple-answers-and-thats-the-point-study-members-say-59289">genetically modified foods</a>, for instance.</p>
<p>But what deserves to be successful isn’t always what ends up winning hearts and minds in the real world. In fact, <a href="https://aaas.confex.com/aaas/2016/webprogram/Paper18139.html">empirical data we collected suggest</a> that the viewership of such shows – even heavily publicized and celebrity-endorsed ones – is small and made up of people who are already highly educated, knowledgeable about science and receptive to scientific evidence.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166715/original/file-20170425-13414-qu005f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166715/original/file-20170425-13414-qu005f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166715/original/file-20170425-13414-qu005f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166715/original/file-20170425-13414-qu005f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166715/original/file-20170425-13414-qu005f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166715/original/file-20170425-13414-qu005f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166715/original/file-20170425-13414-qu005f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166715/original/file-20170425-13414-qu005f.jpg?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"></a>
<figcaption>
<span class="caption">‘Cosmos’‘ pedigree and publicity seemed like they would translate to success….</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/inVision-Frank-Micelotta-Invision-AP-a-ENT-CPAE-/194092c8627d4ef3aa898b073e2f2c83/1/0">Frank Micelotta/Invision for FOX/AP Images</a></span>
</figcaption>
</figure>
<h2>‘Cosmos’ illustrates the issue</h2>
<p>The 2014 reboot of <a href="http://www.carlsagan.com/">Carl Sagan</a>’s popular 1980 series “Cosmos,” starring astrophysicist Neil deGrasse Tyson, is just one recent example. Tyson’s show, “<a href="http://channel.nationalgeographic.com/cosmos-a-spacetime-odyssey/">Cosmos: A Spacetime Odyssey</a>,” aired prime time on Fox and the National Geographic channel, received several <a href="http://www.emmys.com/awards/nominees-winners/2014">Emmy nominations</a> and was considered a critical success in which “Tyson managed to <a href="https://www.washingtonpost.com/news/speaking-of-science/wp/2015/02/26/neil-degrasse-tyson-to-receive-the-national-academy-of-sciences-most-prestigious-honor/?utm_term=.ae59385f7780">educate and excite viewers of all ages</a> across the globe.”</p>
<p>However, Tyson’s efforts to reach a broad audience and preach beyond the proverbial choir fell short. Nielsen ratings indicate the new version of “Cosmos” reached 1.3 percent of television households, which doesn’t compare well even to other science shows and educational programming. PBS’ “NOVA,” for instance, <a href="http://www.sgptv.org/media/pdfs/SGPTV_2016-17_Media_Kit_100416.pdf">typically reaches about 3 percent</a> of households (around <a href="http://www.nielsen.com/us/en/insights/news/2016/nielsen-estimates-118-4-million-tv-homes-in-the-us--for-the-2016-17-season.html">four million viewers</a> a week), and PBS’ other prime time programming usually gets higher Nielsen ratings than “Cosmos” had. “Cosmos” lagged even further behind science entertainment shows like “<a href="http://www.cbs.com/shows/ncis/">NCIS</a>,” which reached 11.2 percent of households, and “<a href="http://www.cbs.com/shows/big_bang_theory/">The Big Bang Theory</a>,” which reached 10.8 percent of households during the same week “Cosmos” aired its first episode.</p>
<p>In 2014, we conducted a <a href="https://aaas.confex.com/aaas/2016/webprogram/Paper18139.html">representative national survey</a> in a collaboration among the University of Wisconsin, the University of Pennsylvania’s Annenberg Public Policy Center and Temple University. We found that 76.1 percent of Americans did not watch any episodes of “Cosmos,” 7.1 percent said they watched one episode, and only 2.4 percent said they watched all 13 episodes.</p>
<p>And there were really no surprises about who tuned in. Respondents who saw at least one episode were 40 percent more likely to be male, 35 percent more likely to claim interest in science, and significantly more knowledgeable about science than those who didn’t watch. Less affluent audiences were less likely to watch at least one episode, as were those who were highly religious. Even those who expressed above-average interest in science watched only 1.5 “Cosmos” episodes on average.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/166716/original/file-20170425-13401-110os80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/166716/original/file-20170425-13401-110os80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166716/original/file-20170425-13401-110os80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=435&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166716/original/file-20170425-13401-110os80.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=435&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166716/original/file-20170425-13401-110os80.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=435&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166716/original/file-20170425-13401-110os80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=547&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166716/original/file-20170425-13401-110os80.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=547&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166716/original/file-20170425-13401-110os80.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=547&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">What science programming will capture the imaginations of those who aren’t already into science?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/two-boys-brothers-watching-tv-attentively-56826280">Watching image via www.shutterstock.com.</a></span>
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<h2>Success is out there?</h2>
<p>Engaging scientific programming could still be an antidote to waning public interest in science, especially where <a href="https://theconversation.com/science-achievement-gaps-start-early-in-kindergarten-65028">formal science education</a> <a href="https://theconversation.com/heres-why-kids-fall-behind-in-science-56785">is falling short</a>. But it is revealing that “Cosmos” – a heavily marketed, big-budget show backed by Fox Networks and “Family Guy” creator Seth McFarlane – did not reach the audience who need quality science information the most. “Bill Nye Saves the World” might not either. Its streaming numbers are not yet available.</p>
<p>Today’s <a href="http://press.princeton.edu/titles/10935.html">fragmented and partisan media environment</a> fosters selective exposure and motivated reasoning – that is, viewers typically tune in to programming that <a href="https://dx.doi.org/10.1037/a0015701">confirms their existing worldview</a>. There are few opportunities or incentives for audiences to <a href="https://dx.doi.org/10.1073/pnas.1320868111">engage with scientific evidence</a> in the media. All of this can propagate misleading claims and deter audiences from accepting the <a href="https://doi.org/10.1073/pnas.1317516111">conclusions of sound science</a>. And adoption of misinformation and alternative facts is <a href="https://theconversation.com/why-each-side-of-the-partisan-divide-thinks-the-other-is-living-in-an-alternate-reality-71458">not a partisan problem</a>. Policy debates questioning or ignoring scientific consensus on vaccines, climate change and GMOs have <a href="https://doi.org/10.1177/0002716214554756">cut across different political camps</a>.</p>
<p>None of this is meant to downplay the huge potential of entertainment media to reach diverse audiences beyond the proverbial choir. We know from decades of research that our mental images of science and its impact on society are <a href="https://doi.org/10.1177/0093650210384988">shaped heavily</a> by (sometimes stereotypical) portrayals of science and scientists in shows like “The Big Bang Theory” or “<a href="http://www.bbcamerica.com/shows/orphan-black">Orphan Black</a>.”</p>
<p>But successful scientific entertainment programming needs to accomplish two goals: First, draw in a diverse audience well beyond those already interested in science; second, present scientific issues in a way that unites audiences around shared values rather than further polarizing by presenting science in ways that seems at odds with specific political or religious worldviews. </p>
<p>While “Cosmos” failed to attract a diverse audience eager to be introduced to the wonders of the universe (and science), there’s still value in the science community and entertainment industry collaboratively developing these kinds of television programs. In order to be successful, however, these collaborations must draw on insights from social science research to maximize the reach of novel diverse formats, communication strategies and media outlets. The National Academies of Sciences, Engineering and Medicine’s <a href="http://scienceandentertainmentexchange.org/">Science and Entertainment Exchange</a>, for instance, tries to connect the entertainment industry and the nation’s best scientists in order to combine the reach of entertainment media’s engaging storytelling with the most accurate portrayal of science.</p>
<p>And social science research suggests that complex information can reach audiences via the most unlikely of places, including the satirical fake news program “The Colbert Report.” In fact, a University of Pennsylvania study showed that a series of “Colbert Report” episodes <a href="http://www.cc.com/video-collections/8iug7x/the-colbert-report-colbert-super-pac/3yzu4u">about Super PACs and 501(c)(4) groups</a> during the 2012 presidential election <a href="http://dx.doi.org/10.1080/15205436.2014.891138">did a better job educating viewers</a> than did mainstream programming in traditional news formats. </p>
<p>Social science can help us learn from our mistakes and better understand how to connect with hard-to-reach audiences via new formats and outlets. None of these shows by themselves will save the world. But if done right, they each might get us closer, one empirical step at a time.</p>
<hr>
<p><em>After publication, “Cosmos: A Spacetime Odyssey” host <a href="https://theconversation.com/go-76630#comment_1276757">Neil deGrasse Tyson responded to this article</a> in a comment.</em></p><img src="https://counter.theconversation.com/content/76630/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 organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Popular programming that focuses on science tends to not actually be all that popular. Bringing in new audiences who aren’t already up to speed on science topics is a challenge.Heather Akin, Post-Doctoral Research Fellow at the Annenberg Public Policy Center, University of PennsylvaniaBruce W. Hardy, Assistant Professor of Strategic Communication, Temple UniversityDietram A. Scheufele, Professor of Life Sciences Communication, University of Wisconsin-MadisonDominique Brossard, Professor and Chair in the Department of Life Sciences Communication, University of Wisconsin-MadisonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/691342016-12-15T19:25:53Z2016-12-15T19:25:53ZBook review: Do we live in A Fortunate Universe?<figure><img src="https://images.theconversation.com/files/149822/original/image-20161213-1610-tpypyi.jpg?ixlib=rb-1.1.0&rect=171%2C0%2C1024%2C655&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Andromeda Galaxy, just part of a finely tuned universe.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/24354425@N03/16024383810/">Flickr/NASA, ESA, J. Dalcanton, B.F. Williams, and L.C. Johnson (University of Washington), the PHAT team, and R. Gendler</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Geraint Lewis and Luke Barnes are two deep-thinking Australian-based astronomers who take us on a guided tour of the universe in their new book <a href="http://www.cambridge.org/au/academic/subjects/physics/history-philosophy-and-foundations-physics/fortunate-universe-life-finely-tuned-cosmos">A Fortunate Universe: Life in a Finely Tuned Cosmos</a>.</p>
<p>Along the way, they cook up a philosophical feast for hungry geeks.</p>
<p>Their style is engaging – a bit like Alice in Wonderland – but with a lot more physics. And their informal banter is so disarmingly informal that by the end we’re on a first name basis with Geraint and Luke.</p>
<p>They introduce us to their favourite movies and music – and their wry sense of humour is not without value. This is an unusual popular science book in which the authors have humanised themselves. Congratulations Geraint and Luke!</p>
<h2>Big questions</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/149994/original/image-20161213-1610-778hj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149994/original/image-20161213-1610-778hj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/149994/original/image-20161213-1610-778hj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=911&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149994/original/image-20161213-1610-778hj1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=911&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149994/original/image-20161213-1610-778hj1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=911&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149994/original/image-20161213-1610-778hj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1145&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149994/original/image-20161213-1610-778hj1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1145&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149994/original/image-20161213-1610-778hj1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1145&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="attribution"><span class="source">Cambridge University Press</span></span>
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<p>This book is for anyone who has ever wondered: “Why is it so?” With colourful analogies and admirably accurate simplifications, Geraint and Luke have succeeded in making much of modern physics and cosmology comprehensible.</p>
<p>They address the biggest questions of science. What is dark energy? What is dark matter? Why is there something rather than nothing? Why is there more matter than antimatter? Where did the laws physics come from? Do we live in a multiverse? Do we live in a simulation? How different could the universe have been? If God is omnipotent, why does evil exist?</p>
<p>Not even the popular scientist and writer <a href="http://cosmos.asu.edu/about">Paul Davies</a> tries to address so many important big questions in one book – and fortunately, Paul only puts God in his <a href="http://cosmos.asu.edu/publication-type/popular-articles-essays">book titles</a>.</p>
<p>Here is how Geraint and Luke describe the main thesis of their book:</p>
<blockquote>
<p>We scratched our heads … and wondered deeply about how things could have been different. This quickly leads to the realisation that life would be very difficult, if not impossible, in the vast sea of possible universes.</p>
<p>You may be asking yourself ‘how could the universe have been different?’ and the answer is the fundamental laws of matter and energy could have been different. There are basic quantities that theorists cannot calculate; we have to cheat by getting the answer from experiments. These loose ends cry out for a deeper understanding.</p>
</blockquote>
<p>My comment on that is: “Hmmm … maybe.”</p>
<h2>Why the constants?</h2>
<p>We physicists are always trying to come up with better equations to describe the universe. In our equations for <a href="https://www.britannica.com/science/gravity-physics">gravity</a>, for example, there is a constant that we call “G”. It represents the strength of gravity. </p>
<p>Geraint and Luke seem comfortable imagining universes with different values of G. If G were ten times larger, gravity would be so strong that you couldn’t walk. If G were ten times smaller, there wouldn’t be an Earth to walk on. </p>
<p>We have tried to derive the value of G from a more fundamental theory, but have had little success. The only thing we can do with G is <a href="http://www.nature.com/nphys/journal/v12/n2/full/nphys3651.html">measure it</a>. So in some sense, G seems arbitrary. The only explanation for its arbitrary value – according to Geraint and Luke – is that it has been fine tuned to allow life to exist in our universe.</p>
<p>They call this fine tuning “a fact” and then spend most of the book trying to explain this “fact”.</p>
<p>Geraint and Luke define fine tuning like this:</p>
<blockquote>
<p>Something is fine tuned if, to explain the data, you must make an unmotivated but suspiciously precise assumption. </p>
</blockquote>
<p>I agree with that, but notice that in this sentence, the “something” that is fine tuned could be the theory (which is the normal way physicists use the term fine tuning), or it could be the universe.</p>
<p>If you hang around theoretical physicists for more than an hour in a pub talking shop, you will hear the phrase “fine tuning”. It is the most common insult that we heap on each other’s pet theories: “You’re trying to explain the remarkable spatial flatness of the universe with a remarkably flat <a href="https://arxiv.org/abs/astro-ph/9508078">inflaton potential</a>. That’s fine tuning. You’re cheating. Your theory stinks.” </p>
<p>We try hard to make our theories natural, but to fit the universe we live in, our equations need what seem like arbitrary constants that we haven’t been able to explain at any deeper level. </p>
<p>Rather than blame our current theories for this shortcoming, and rather than calling the <em>theories</em> fine tuned, the authors think that our <em>universe</em> is fine tuned.</p>
<p>For something to be fine tuned, there have to have been other possibilities. Geraint and Luke explain:</p>
<blockquote>
<p>[…] what if almost all of the possible universes are sterile, with conditions too simple or extreme for life of any conceivable type to arise? Then we are faced with a conundrum. Why, in the almost infinite sea of possibilities, was our universe born with the conditions that allow life to arise? That is the subject of this book.</p>
</blockquote>
<p>Imagining an almost infinite sea of unfortunate possibilities would make anyone feel fortunate not to be in that sea. </p>
<p>Geraint and Luke argue, if you take the number of universes that are compatible with life and divide by the number of all possible universes, that ratio must be tiny. Hence the title of the book A Fortunate Universe. </p>
<h2>Fine tuned by what?</h2>
<p>We can’t currently derive those pesky physical constants (such as G) so we have to resort to only measuring them. </p>
<p>Interpreting this as evidence for a supernatural being who fine tunes the universe so that we can exist is not a very humble interpretation of the data. But for 25 pages near the end of the book, Luke argues that God is the fine tuner.</p>
<p>Saying that the universe is fine tuned for life makes as much sense to me as saying that my legs are fine tuned to reach the ground. The case for our theories being incomplete and not as fundamental as we would like, is more compelling to me as a scientist than the idea that any god fine tuned the universe for us. </p>
<p>To <a href="http://www.azquotes.com/quote/719877">paraphrase</a> the American theoretical physicist and cosmologist <a href="http://krauss.faculty.asu.edu/">Lawrence Krauss</a>: The lack of understanding of physical constants is not evidence for God. It’s evidence of a lack of understanding.</p>
<p>If you’re a scientifically minded theist looking for your God in the universe, this book is invaluable. If you’re a strident atheist, this book is a long god-of-the-ultimate-gap argument and just another theistic salvo for intelligent design. </p>
<p>I enjoyed the book a lot, but I disagreed with the main thesis. No matter what your religious beliefs are, this book will make you think.</p>
<hr>
<p><em>A Fortunate Universe: Life in a Finely Tuned Cosmos</em></p>
<p><em>By Geraint Lewis and Luke Barnes</em></p>
<p><em>Published by <a href="http://www.cambridge.org/au/academic/subjects/physics/history-philosophy-and-foundations-physics/fortunate-universe-life-finely-tuned-cosmos?format=HB">Cambridge University Press</a> (A$56.95)</em></p><img src="https://counter.theconversation.com/content/69134/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charley Lineweaver 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>A new book explores some of the big questions of why the universe exists and why it seems fine-tuned for life.Charley Lineweaver, Researcher at Research School of Astronomy and Astrophysics and the Research School of Earth Sciences, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/461572015-09-03T13:18:46Z2015-09-03T13:18:46ZThe fate of the universe: heat death, Big Rip or cosmic consciousness?<figure><img src="https://images.theconversation.com/files/93520/original/image-20150901-13443-kp3nxx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Black holes will be all that remains before the universe enters heath death. But the story doesn't end there...</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Future_of_an_expanding_universe#/media/File:BlackHole.jpg">NASA/ESA/wikimedia</a></span></figcaption></figure><p>By piecing together an increasing number of clues, cosmologists are getting closer to understanding what the future and ultimate fate of the universe will be. And I’m afraid the news is not good. Star formation will cease and black holes will take over until they eventually evaporate into nothingness. There could even be a “Big Rip” on the horizon. But for those who don’t mind waiting another 10<sup>10<sup>50</sup></sup> years or so, things may start to look up as a number of bizarre events could take place.</p>
<p>But before we consider random events in the very far future, let’s start with what we know about the past and the present. </p>
<h2>The past</h2>
<p>The reason we can investigate the past evolution of the universe is that, in some regards, astronomy is analogous to archaeology. Explicitly: the further we peer away from our home planet, the further back in time we see in to the universe. And when we look far back in time, we observe that galaxies are closer together than they are at present. Although only <a href="https://theconversation.com/one-funeral-at-a-time-big-bang-denial-and-the-search-for-truth-11127">one strand of evidence among many</a>, this observation – coupled with Einstein’s theory of general relativity – means that the <a href="https://theconversation.com/god-the-big-bang-next-please-1871">universe started with a Big Bang</a> and has been expanding ever since. </p>
<h2>The present</h2>
<p>Late last century, one of the most pressing issues in modern cosmology was to measure the deceleration rate of the universe. Given the amount of mass observed in the cosmos it was thought that it might be enough to cause an eventual contraction of the expansion. </p>
<p>Remarkably, two independent teams of scientists found the exact opposite. The universe was not slowing down in its expansion, it was accelerating. This <a href="https://theconversation.com/nobel-prize-win-tells-us-the-universe-is-accelerating-what-does-that-mean-3753">profound discovery</a> lead to the Nobel prize in physics in 2011. However, understanding the implications of it remains challenging. </p>
<p>One way to think about the accelerating universe is that there must be some kind of material (or field) that permeates the universe that exerts a negative pressure (or a repulsive gravity). We call this <a href="https://theconversation.com/explainer-the-mysterious-dark-energy-that-speeds-the-universes-rate-of-expansion-40224">dark energy</a>. </p>
<p>This may sound a bit far-fetched, but independent experiments have been conducted to corroborate the acceleration of the universe and the existence of dark energy. From 2006, I was involved in the <a href="http://wigglez.swin.edu.au/site/">WiggleZ Dark Energy Survey</a> – a scientific experiment to independently confirm the acceleration. Not only did we find that the acceleration is happening, but we provided compelling evidence that the cause of this was dark energy. We observed that dark energy was retarding the growth of massive superclusters of galaxies. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/93521/original/image-20150901-13422-kchauj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/93521/original/image-20150901-13422-kchauj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/93521/original/image-20150901-13422-kchauj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/93521/original/image-20150901-13422-kchauj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/93521/original/image-20150901-13422-kchauj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/93521/original/image-20150901-13422-kchauj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/93521/original/image-20150901-13422-kchauj.png?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">
<figcaption>
<span class="caption">The growth rate of superclusters like Virgo is providing strong evidence for the existence of dark energy.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:6_Virgo_Supercluster_%28blank%29.png">Andrew Z. Colvin/wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We therefore suggested that <a href="http://wigglez.swin.edu.au/site/prmay2011_files/wigglez_mediarelease.pdf">dark energy is real</a>. If the concept of dark energy and its repulsive gravitation force is too weird, then an alternative to consider is that perhaps our theory of gravitation needs to be modified. This might be achieved in a similar way that relativity advanced Newtonian gravitation. Either way, we need new physics to explain it. </p>
<h2>The future</h2>
<p>Before turning to the very distant future, I will mention another relevant survey: <a href="http://www.gama-survey.org">GAMA</a>. Using that survey, we found that <a href="https://theconversation.com/dont-panic-but-the-universe-is-slowly-dying-45779">the universe is slowly “dying”</a>. Put another way: the peak era of star formation is well behind us, and the universe is already fading.</p>
<p>The more “immediate” future can be predicted with some certainty. Five billion years from now, the <a href="http://www.scientificamerican.com/article/the-sun-will-eventually-engulf-earth-maybe/">sun will enter its red giant phase</a>. Depressingly, no more than two more billion years after that, it will consume Earth.</p>
<p>After that, the relative strength of dark energy and how it might vary over time becomes important. The stronger and faster the repulsive force of dark energy is, the more likely it is that the universe will experience a <a href="http://www.telegraph.co.uk/news/science/science-news/11715091/Big-Rip-will-end-the-universe-scientists-claim.html">Big Rip</a>. Put bluntly: the Big Rip is what happens when the repulsive force of dark energy is able to overcome gravitation (and everything else). Bodies that are gravitationally bound (such as our local supercluster, our own Milky Way galaxy, our solar system, and eventually ourselves) <a href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.91.071301">become ripped apart</a> and all that is left is (probably) lonesome patches of vacuum.</p>
<p>The data from the WiggleZ survey and other experiments do not rule out the Big Rip, but push it in to the exceptionally far future (if at all). </p>
<p>Somewhat more pressing is the heat death of the universe. As the universe carries on expanding, we will no longer be able to observe galaxies outside our local group (100 million years from now). Star formation will then cease in about <a href="http://arxiv.org/abs/astro-ph/9701131">1-100 trillion years</a> as the supply of gas needed will be exhausted. While there will be some stars around, these will run out of fuel in some 120 trillion years. All that is left at that point is stellar remnants: black holes, neutron stars, & white dwarfs being the prime examples. One hundred quintillion (10<sup>20</sup>) years from now, most of these objects will be swallowed up by the supermassive <a href="https://theconversation.com/explainer-black-holes-7431">black holes</a> at the heart of galaxies. </p>
<p>In this way, the universe will get darker and quieter until there’s not much going on. What happens next will depend on how fast the matter in the universe decays. It is thought that protons, which make up atoms along with neutrons and electrons, spontaneously decay into subatomic particles if you just wait long enough. The time for all ordinary matter to disappear has been calculated to be 10<sup>40</sup> years from now. Beyond this, only black holes will remain. And even <a href="http://journals.aps.org/prd/abstract/10.1103/PhysRevD.13.198">they will evaporate away</a> after some 10<sup>100</sup> years. </p>
<p>At this point, the universe will be nearly a vacuum. Particles that remain, like electrons and light particles (photons), are then very far apart due to the universe’s expansion and rarely – if at all – interact. This is the true death of the universe, dubbed the “heat death”. </p>
<p>The idea comes from the <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html">second law of thermodynamics</a>, which states that entropy – a measure of “disorder” or the number of ways a system can be arranged – always increases. Any system, including the universe, will eventually evolve into a state of maximum disorder – just like a sugar cube will always dissolve in a cup of tea but would take an insanely long time to randomly go back to an orderly cube structure. When all the energy the in the cosmos is uniformly spread out, there is no more heat or free energy to fuel processes that consume energy, such as life.</p>
<h2>Boltzmann Brains and new Big Bangs</h2>
<p>All of the above seem very bleak to say the least. So I will end this article on a highly speculative, <a href="http://arxiv.org/abs/1405.0298">probably wrong</a>, completely untestable, but more positive, note. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/93514/original/image-20150901-13401-gr8hdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/93514/original/image-20150901-13401-gr8hdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/93514/original/image-20150901-13401-gr8hdc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/93514/original/image-20150901-13401-gr8hdc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/93514/original/image-20150901-13401-gr8hdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/93514/original/image-20150901-13401-gr8hdc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/93514/original/image-20150901-13401-gr8hdc.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">Fishy? The far future of the universe could rather bizarre.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/akrockefeller/13892653941/in/photolist-naDu1e-6YrhaZ-4GXcBN-dJu9p4-aCRcEK-h7eHjh-dPu5Dj-dJu49c-dYqyPu-dPotf8-dQ9ijS-pGKkVe-p8ndvK-oRK77J-oRK73q-66vM1x-c2bt3J-oRJymP-9qKL2b-dYqzeW">AK Rockefeller/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>According to the strange rules of quantum mechanics, random things can pop up from a vacuum. And it is not just a mathematical quirk: the existence of particles suddenly coming into existence and then disappearing again is seen constantly in particle physics experiments. However, there is no reason why so-called “quantum fluctuations” could not give rise to an entire atom. </p>
<p>There has even been speculation that a “brain”, dubbed a <a href="https://www.newscientist.com/article/mg22229692.600-quantum-twist-could-kill-off-the-multiverse/">Boltzmann brain</a>, could be created in this context. The timescale for such a thing to appear? Well, that has been computed at <a href="http://iopscience.iop.org/article/10.1088/1475-7516/2007/01/022">10<sup>10<sup>50</sup></sup> years</a>.</p>
<p>And a new Big Bang? That could be on the way <a href="http://arxiv.org/abs/hep-th/0410270">in some 10<sup>10<sup>10<sup>56</sup></sup></sup> years</a>. </p>
<p><em>Read other stories from our cosmology series <a href="https://theconversation.com/uk/topics/cosmology-series">here</a></em></p><img src="https://counter.theconversation.com/content/46157/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Pimbblet 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 about 10100 years, the universe will have passed away in a tragic ‘heat death’. But don’t despair, eventually random conscious brains may pop out in empty space to shake things up.Kevin Pimbblet, Senior Lecturer in Physics, University of HullLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/447582015-07-16T04:57:21Z2015-07-16T04:57:21ZWhat might Pluto sound like? Our musical love affair with the cosmos<figure><img src="https://images.theconversation.com/files/88598/original/image-20150716-26289-de09w9.jpg?ixlib=rb-1.1.0&rect=0%2C129%2C979%2C685&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Music and astronomy have been intimately linked since antiquity.</span> <span class="attribution"><span class="source">AAP Image/ NASA</span></span></figcaption></figure><p>Fans of astronomy who also have a musical bent may have experienced a “what if” moment this week. With NASA’s <a href="https://www.nasa.gov/mission_pages/newhorizons/main/index.html">New Horizons</a> currently thrilling the world with the <a href="https://theconversation.com/live-blog-new-horizons-flyby-of-pluto-44670">best ever images</a> of the dwarf planet, it would have been the perfect time to bust out a recording of <a href="http://www.gustavholst.info/biography/index.php?chapter=1">Gustav Holst</a>’s symphonic suite, The Planets, and propose a toast to Pluto.</p>
<p>Unfortunately, Holst didn’t write a movement for Pluto. Exactly 100 years ago, Holst was halfway through composing what would become his most famous work, but Pluto wasn’t <a href="http://news.sciencemag.org/space/2015/07/new-planet-beyond-neptune-year-we-discovered-pluto">discovered</a> until 1930, four years before the <a href="http://www.gustavholst.info/biography/index.php?chapter=6">composer’s death</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/AHVsszW7Nds?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Gustav Holst’s seven-movement orchestral suite, The Planets (1914-16).</span></figcaption>
</figure>
<p>Holst was apparently <a href="http://www.gustavholst.info/compositions/listing.php?work=18">uninterested</a> in updating his planetary audio tour, slightly resenting the work’s popularity and the corresponding attention deficit afforded his other compositions.</p>
<p>Resentment may have given way to pride had he known just how influential and <a href="http://www.imdb.com/name/nm0392304/">ubiquitous</a> The Planets would become, especially in cinema.</p>
<p>The Imperial March from Star Wars, for example, was clearly based on Mars, The Bringer of War, the first movement in the video of The Planets above. Not so much as stealing, <a href="http://www.biography.com/people/john-williams-9532526">John Williams</a> was probably honouring <a href="http://www.imdb.com/name/nm0000184/">George Lucas</a>’s request to recreate the spirit of Holst – an acknowledgement of the grip Holst’s music has on the public’s imagining of outer space.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/8VwkyrTb6go?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">John Williams – Star Wars’ The Imperial March (1980).</span></figcaption>
</figure>
<p>The fact that Holst was actually composing music based on <em>astrologically</em> inspired themes rather than astronomical (hence no “Earth” movement) is curiously beside the point now – we are so used to hearing this music appropriated for the purpose of making imagined outer space audible.</p>
<p>Humans have always turned to music to help deal with the profoundly confronting enormity of the cosmos.</p>
<p>From humming Twinkle Twinkle Little Star to a child at bedtime while peering through the window at the night sky, to <a href="http://www.imdb.com/name/nm0000040/">Stanley Kubrick</a> <a href="http://www.newyorker.com/magazine/2013/09/23/space-is-the-place">exploiting</a> the raw power of <a href="http://www.johann-strauss.org.uk/strauss.php?id=121">Strauss</a> and the luminous intricacy of <a href="http://www.schott-music.com/shop/persons/featured/gyoergy-ligeti/">Ligeti</a> in <a href="http://www.imdb.com/title/tt0062622/">2001: A Space Odyssey</a>, somehow music and the cosmos go together.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/3XyS7uCtnq0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Opening sequence for Stanley Kubrick’s 2001: A Space Odyssey (1968).</span></figcaption>
</figure>
<p>One of the most emotionally resonant items aboard NASA’s <a href="http://voyager.jpl.nasa.gov/where/">Voyager 1 spacecraft</a> on its interstellar journey is of course the <a href="http://voyager.jpl.nasa.gov/spacecraft/goldenrec.html">Golden Record</a>, with its extensive and diverse <a href="https://theconversation.com/beyond-the-morning-star-the-real-tale-of-voyagers-aboriginal-music-18288">musical selection</a>.</p>
<p>The 90-minute sampling of music from around the globe is hardly tokenistic and it implies that humanity regards music as a very good foot to put forward when sending messages to alien civilisations.</p>
<h2>The Music of the Spheres</h2>
<p>This is all nothing new – music and astronomy have been intimately linked since antiquity.</p>
<p>An inaudible expression of mathematics via harmony, the <a href="http://www.sensorystudies.org/picture-gallery/spheres_image/">Music of the Spheres</a> was thought to determine the celestial dance moves of the planets and moons.</p>
<p>It all stemmed from Greek mathematician <a href="http://www.britannica.com/biography/Pythagoras">Pythagoras</a>’s discovery that pitch is proportionally related to the length of the sounding body such as a string or air column, and that what humans perceive as “harmonious”-sounding intervals (two pitches sounding at the same time) corresponded with simple mathematical ratios.</p>
<p>Pythagoras’ 2,600-year-old <a href="https://en.wikipedia.org/wiki/Musica_universalis#History">suggestion</a> that planetary bodies emit a kind of orbital hum may have been off the mark in terms of function (believing the inaudible vibrations affected everyday life on Earth) but not in substance.</p>
<p>Translations of radio and electromagnetic waves from space into audible sound make for <a href="http://www-pw.physics.uiowa.edu/space-audio/">eerie listening</a>.</p>
<p>The pioneering American composer <a href="http://terryriley.net/">Terry Riley</a> <a href="http://www.npr.org/templates/story/story.php?storyId=930399">wrote</a> an evening-length composition based on sounds collected from across the solar system in collaboration with a scientist and the Kronos string quartet:</p>
<figure>
<iframe src="https://player.vimeo.com/video/9213829" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Kronos Quartet: Sun Rings (2002).</span></figcaption>
</figure>
<p>You can even listen to a <a href="http://www.radio-astronomy.net/index.htm">live performance</a> by space 24 hours a day, seven days a week if you so desire, or a <a href="http://lightyear.fm/">playback</a> of all radio waves that have travelled away from Earth since we began transmitting radio. </p>
<p>Despite this history of recruiting our aural imagination to help get our minds around space, I do wonder what kind of humanly constructed sound could actually do Pluto justice.</p>
<p>Rejected for a time by size-ist scientists, invited back on new terms, and for many ever-associated with a <a href="http://www.imdb.com/character/ch0027779/">cute dog cartoon</a> by <a href="http://www.disney.com.au/">Disney</a>, the sheer mysteriousness of Pluto is somewhat obscured by the jokes.</p>
<p>So many educational posters line the planets up like snooker balls, for eminently practical reasons, that our sense of Pluto’s vast distance from us is rarely accurate.</p>
<p>A <a href="http://www.vox.com/2015/7/13/8947339/new-horizons-pluto-mission-nasa#ooid=81NGQ0djoP4shu015hc2FomKCLo1sfxJ">recent video on Vox</a> explains that if Earth were the size of a basketball, then Pluto would be a golf ball. Maintaining that scale, the two objects would have to be more than 80 kilometres apart to accurately reflect how far away Pluto is.</p>
<p>Words like “cold” and “lonely” don’t seem to capture the devastating isolation Pluto endures, a vantage point from which the sun appears as not much more than a bright star.</p>
<p>The visionary German composer <a href="http://www.karlheinzstockhausen.org/">Karlheinz Stockhausen</a> wasn’t afraid to venture past Pluto, into deep musical space. His mid-1970s musical drama <a href="http://www.theguardian.com/music/2005/oct/13/classicalmusicandopera">Sirius</a> brings us some fantastically original and imaginative sounds courtesy of four emissaries from a planet orbiting Sirius. The extensive use of electronically generated sounds in addition to the live performers gives this music its unearthly quality.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/1G3b65VU3L4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Karlheinz Stockhausen’s Sirius, Part 1 of 2 (1975-77).</span></figcaption>
</figure>
<h2>A lonely planet</h2>
<p>At least <a href="http://www.hyperion-records.co.uk/dc.asp?dc=D_CDH55350">one composer</a> has taken up the challenge to complete Holst’s Planets, but his version of Pluto was designed to work well in a complete performance of the original suite, more or less connected to the planets-as-astrology approach of Holst.</p>
<p>Are there undreamt-of sounds lurking in humanity’s various musical languages that could truly evoke Pluto-ness in all its mind-bending solitude? Will even deeper relationships between sound and space be discovered by scientists?</p>
<p>I suspect the answers will be yes, and I can’t wait to hear what the music will be like.</p><img src="https://counter.theconversation.com/content/44758/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Liam Viney 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>From Twinkle Twinkle to Space Odyssey and beyond, humans have always turned to music to help deal with the profoundly confronting enormity of the cosmos. Is that a match made in the heavens?Liam Viney, Piano Performance Fellow , The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/408702015-05-08T04:30:09Z2015-05-08T04:30:09ZThe science behind the Square Kilometre Array<figure><img src="https://images.theconversation.com/files/80835/original/image-20150507-1219-1xxnjmd.jpg?ixlib=rb-1.1.0&rect=0%2C1571%2C5000%2C3106&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wide-eyes: the Square Kilometre Array in the Karoo in South Africa.</span> <span class="attribution"><a class="source" href="https://www.skatelescope.org/wp-content/uploads/2015/04/Afr_SkaCloseUp_V2.full.jpg">SKA</a></span></figcaption></figure><p>By now, most people with even a passing interest in science will have heard about the Square Kilometre Array (SKA). It is the world’s largest radio telescope, and will operate over sites in <a href="https://theconversation.com/the-square-kilometre-array-finally-has-a-home-or-two-7274">South Africa and Western Australia</a>. </p>
<p>But exactly what will this telescope do? And what are the scientific questions that it one day may be able to answer?</p>
<p>The SKA will be 50 times more sensitive and 10,000 faster than the best radio telescopes we have today. It will have the capacity to produce images with resolution quality 50 times higher than the <a href="http://hubblesite.org/">Hubble Space Telescope</a>. </p>
<p>The SKA’s greater sensitivity will expand the range of the observable universe and has the potential to answer profound questions in astrophysics, cosmology and fundamental physics. </p>
<h2>How the SKA works</h2>
<p>Modern radio telescopes are collections of antennae that are scattered over a large area. Using a technique called interferometry, they behave as a single dish, with a total collecting area of all the antennas combined – up to one square kilometre for the SKA. </p>
<p>With this and other modern instruments, teams of astronomers will readily be able to see the universe in ever greater detail at all wavelengths of light. </p>
<p>The SKA will detect hydrogen, the most abundant element in the universe. Neutral hydrogen is the basic building block for stars – stars form when hydrogen clouds collapse under their own gravity. Once galaxies form not all the hydrogen is in stars, and it is this remaining hydrogen that we see with radio telescopes.</p>
<h2>Five key questions SKA will address</h2>
<p>1) Through SKA, we will be able to go back to when the first stars and black holes formed an era known as the “Dark Ages”. It will provide a time lapse of the universe allowing astronomers to learn about the mechanisms by which the first structures were created.</p>
<p>2) The SKA will also directly probe <a href="https://theconversation.com/explainer-einsteins-theory-of-general-relativity-3481">Einstein’s theory of general relativity</a> using highly magnetised and rapidly spinning neutron stars known as pulsars. These pulsars are cosmic lighthouses, emitting a pulse of radiation at very precise intervals. </p>
<p>Due to the exact timing of the pulses, they can be used as cosmic clocks. By locating pulsars that are orbiting black holes and timing them, we can study general relativity in extreme gravity conditions as well as testing the predictions that general relativity makes about the black hole itself. </p>
<p>General relativity also predicts the existence of gravitational waves – literally waves in the space-time continuum. By monitoring an array of these clocks with the SKA, we can try to detect disturbances caused by a passing gravitational wave which would have a known signature.</p>
<p>3) By mapping the hydrogen in a billion galaxies, the SKA will reveal the large-scale structure of the universe. This will allow us to study how galaxies form and evolve. Mapping the distribution of hydrogen across the cosmos will also shed light on the mystery of why the expansion of the universe is accelerating. </p>
<p>Scientists detected this accelerated expansion in 1998 – a feat that won them the <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2011/">Nobel Prize in Physics in 2011</a> – and its cause is attributed to a mysterious and unknown “dark energy”. Understanding this dark energy is one of the SKA’s key science goals.</p>
<p>4) Another important area is the study of <a href="http://hubblesite.org/newscenter/archive/releases/2007/17/image/a/">dark matter</a>. Astronomers have been aware of dark matter for some time, and believe that it makes up most of the matter density in the universe, yet its direct detection remains elusive. The SKA will provide ways to map the dark matter distribution across the universe as well as provide ways to probe it a fundamental physics level.</p>
<p>5) We know that magnetic fields are ubiquitous in our universe and are present in planets, stars and galaxies not least our own earth and sun. Yet very little is known about their origin. </p>
<p>The challenge in studying these magnetic fields is that while stars and galaxies can be seen because they emit light, magnetic fields can only be seen through their polarising effect on light. </p>
<p>The SKA’s unique capabilities to detect polarised light will transform the study of magnetic fields and address topics such as the shape and strength of magnetic field in the Milky Way and how it compares to other galaxies. </p>
<h2>One more thing: is there anything out there?</h2>
<p>Perhaps the most important question the SKA will address is simply this: “Are we alone in the universe?” It will be able to probe the regions around stars where earth-like planets are most likely to form and where the environments could potentially sustain life. </p>
<p>Astrobiologists will be able to use the SKA to look for the building blocks of life – amino acids. We will be able to search much larger regions than ever before for signs of extraterrestrial life. </p>
<p>The SKA’s extreme sensitivity makes it able to detect airport strength radar signals on planets many tens of light years away. This means we could directly detect extraterrestrial signals, and perhaps one day listen to alien FM.</p><img src="https://counter.theconversation.com/content/40870/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Prina Patel receives funding from the SKA South Africa Project. </span></em></p>The Square Kilometre Array is the world’s largest telescope – what will it do and how does it work?Prina Patel, SKA Postdoc in Observational Cosmology, University of the Western CapeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/373042015-02-09T05:47:11Z2015-02-09T05:47:11ZHow big is the biggest star we have ever found?<figure><img src="https://images.theconversation.com/files/71323/original/image-20150206-28618-1e7h56c.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spot the biggest.</span> <span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/File:UY_Scuti_zoomed_in,_Rutherford_Observatory,_07_September_2014.jpeg">Rutherford Observatory</a></span></figcaption></figure><p>The universe is such a big place that it is easy to get baffled by the measurements that astronomers make. The size of UY Scuti, possibly one of the largest stars we have observed to date, is certainly baffling.</p>
<p>Not surprisingly, UY Scuti is classified as a “<a href="http://space.about.com/od/stars/a/Hypergiant-Stars.htm">hypergiant</a>” star – which is the classification which comes after “<a href="http://www.kidsastronomy.com/stars/super_giant_star.html">supergiant</a>” and regular “<a href="http://www.kidsastronomy.com/stars/giant_star.html">giant</a>”. Its size may make it the biggest, but it is not the most massive star (where the “mass” in massive stands for the amount of matter in the star). </p>
<p>UY Scuti’s mass is probably slightly more than 30 times the mass of our sun, which places it nowhere near the top of the most massive stars list. That honour is held by a star with the charming name of <a href="http://www.wikiwand.com/en/R136a1">R136a1</a>, which clocks in at 265 times as massive as the sun, but only 30 times the radius of the sun. Mass and physical size don’t always correlate for stars, particularly the case for giant stars.</p>
<p>So while UY Scuti is only around 30 times more massive than the sun, it has a radius somewhere in the region of 1,700 times larger than the radius of the sun. This star is one of a class of stars that varies in brightness because it varies in size, so this number is also likely to change over time. The margin of error on this measurement is about 192 solar radii. This uncertainty is why I used “possibly one of the largest stars” in my description of UY Scuti. If it is smaller by 192 solar radii, there are a <a href="http://www.wikiwand.com/en/List_of_largest_known_stars">few other candidates</a> that would beat UY Scuti.</p>
<p>The approximate size of the star is about 750m miles, or nearly eight astronomical units, where one astronomical unit is the distance between the earth and the sun. This is large enough that it would extend past Jupiter.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/71332/original/image-20150206-28618-18cuf3x.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/71332/original/image-20150206-28618-18cuf3x.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=783&fit=crop&dpr=1 600w, https://images.theconversation.com/files/71332/original/image-20150206-28618-18cuf3x.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=783&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/71332/original/image-20150206-28618-18cuf3x.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=783&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/71332/original/image-20150206-28618-18cuf3x.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=984&fit=crop&dpr=1 754w, https://images.theconversation.com/files/71332/original/image-20150206-28618-18cuf3x.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=984&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/71332/original/image-20150206-28618-18cuf3x.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=984&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">UY Scuti size comparison to the sun.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/File:UY_Scuti_size_comparison_to_the_sun.png">Philip Park</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The complication with stars is that they have diffuse edges. Most stars don’t have a rigid surface where the gas ends and vacuum begins, which would have served as a harsh dividing line and easy marker of the end of the star. </p>
<p>So in order to usefully define the “edge” of a star, we use the location of the photosphere. The photosphere is where the star becomes transparent to light, and where photons – that is, light particles – can escape. As far as an astrophysicist is concerned, this is the surface of the star, as this is the point at which photons can leave the star. Going any further towards the centre of star would mean photons caught in a series of bounces, and unable to stream freely.</p>
<p>To be clear, the photosphere is not where the gas of the star ends – stars also have atmospheres, which are transparent to light, and which extend beyond the photosphere. But the atmosphere is not considered to be part of the star when it comes to defining its radius.</p>
<p>For UY Scuti, whose photosphere extends beyond the orbit of Jupiter, this means that the light produced in the centre of the star would not be able to stream freely from the star until it had made it beyond Jupiter. Beyond that, there would be a diffuse, hot atmosphere which would extend even further out into our solar system, and a large amount of gas and dust which was lost from the star over the years. This nebula of gas lost from the star extends out to 400 astronomical units, which is 10 times further out than Pluto.</p><img src="https://counter.theconversation.com/content/37304/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This article was originally published on Astroquizzical.com</span></em></p>The universe is such a big place that it is easy to get baffled by the measurements that astronomers make. The size of UY Scuti, possibly one of the largest stars we have observed to date, is certainly…Jillian Scudder, Postdoctoral Research Fellow in Astrophysics, University of SussexLicensed as Creative Commons – attribution, no derivatives.