tag:theconversation.com,2011:/us/topics/space-weather-12489/articlesSpace weather – The Conversation2024-03-27T17:09:15Ztag:theconversation.com,2011:article/2258662024-03-27T17:09:15Z2024-03-27T17:09:15ZThe April 8 eclipse provides a rare opportunity to witness the sun’s superhot corona<figure><img src="https://images.theconversation.com/files/584383/original/file-20240326-16-cpzqx3.jpg?ixlib=rb-1.1.0&rect=0%2C2%2C1888%2C1057&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The corona of the sun can be clearly seen in this image taken in 2007.</span> <span class="attribution"><a class="source" href="https://images.nasa.gov/details/PIA09320">(NASA/JPL-Caltech/NRL/GSFC)</a></span></figcaption></figure><p>Being within a narrow path across Mexico, the United States and eastern Canada on April 8 will give a rare chance to see the hottest thing any human ever sees: the corona surrounding the sun.</p>
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Read more:
<a href="https://theconversation.com/on-april-8-2024-parts-of-ontario-quebec-the-maritimes-and-newfoundland-will-see-a-total-eclipse-of-the-sun-heres-how-to-get-ready-for-it-203382">On April 8, 2024, parts of Ontario, Québec, the Maritimes and Newfoundland will see a total eclipse of the sun. Here's how to get ready for it.</a>
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<p>The word “corona” means “crown” — during the eclipse, it becomes visible, and streaming plasma leaving the sun appears in amazing patterns.</p>
<p>This outer atmosphere shines with a strange whitish light, and is safe to look at once the bright surface of the sun is fully obscured. However, it is not safe to look at partial phases of the eclipse without <a href="https://theconversation.com/total-solar-eclipses-while-stunning-can-damage-your-eyes-if-viewed-without-the-right-protection-221381">suitable eye protection</a> such as an approved filter or a <a href="https://svs.gsfc.nasa.gov/14391/">shadow box</a>. </p>
<p>Humankind has been awed by this spectacle <a href="https://www.wired.com/2008/05/may-28-585-bc-predicted-solar-eclipse-stops-battle/">for a very long time without understanding it</a>. Astronomers now know the sun’s corona is heated to up to <a href="https://www.nasa.gov/science-research/heliophysics/nasas-parker-solar-probe-and-the-curious-case-of-the-hot-corona/">two million degrees Kelvin</a>, numerically almost equivalent to Celsius for such high temperatures. </p>
<p>What astronomers haven’t figured out yet is why the corona is so hot.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/ykkrf87WsLI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">NASA scientists describe photographing the sun’s corona during the 2015 eclipse.</span></figcaption>
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<h2>Heat and density</h2>
<p>The surface of the sun has a temperature of <a href="https://scied.ucar.edu/learning-zone/sun-space-weather/surface-of-the-sun">only about 5,800 kelvins</a> (5,500 C). The reason that we can safely look at the corona but must avoid looking at the surface has to do with density: <a href="https://spaceplace.nasa.gov/sun-corona/en/">the corona is very thin</a>, and most of the light we see is reflected sunlight from the surface. </p>
<p>The sun’s surface has enough density that, at its temperature, it emits about <a href="https://www.pveducation.org/pvcdrom/properties-of-sunlight/solar-radiation-in-space">65 megawatts for each square meter</a>. Even diluted by <a href="https://earthsky.org/space/what-is-the-astronomical-unit/">distance from the sun of 150 million kilometres</a>, this is enough to cause immediate eye damage.</p>
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Read more:
<a href="https://theconversation.com/total-solar-eclipses-while-stunning-can-damage-your-eyes-if-viewed-without-the-right-protection-221381">Total solar eclipses, while stunning, can damage your eyes if viewed without the right protection</a>
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<p>Since the corona is such thin gas, despite its high temperature, it does not emit nor reflect much light. For this reason, we can see it only when the body of the sun is completely blocked by the moon. Otherwise the scattered light in our atmosphere completely overwhelms it.</p>
<p>The mystery of the corona’s heat <a href="https://www.americanscientist.org/article/revealing-the-true-solar-corona">puzzled 19th-century astronomers</a>. At the time, new instruments had been developed to study <a href="https://www.azooptics.com/Article.aspx?ArticleID=1984">the composition of celestial bodies</a>.</p>
<p>In 1704, Sir Isaac Newton had discovered that “white” light could be split into colors, a result <a href="https://library.si.edu/digital-library/book/optickstreatise00newta">published in <em>Opticks</em></a>. Unfortunately, his basic views about light were wrong and likely set back the development of optical science 100 years! </p>
<p>Only in the early 1800s were instruments developed, largely setting the stage for the <a href="https://www.zeiss.com/corporate/en/about-zeiss/past/history/locations.html">immensely profitable German optical industry</a>. This allowed scientists to find out what materials were made of by the light they emitted when heated. </p>
<p>A staple of such studies was the <a href="https://www.britannica.com/science/Bunsen-burner">Bunsen burner</a>, originally developed not to have a colour like other flames do.</p>
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<a href="https://images.theconversation.com/files/582669/original/file-20240318-16-fmoksh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a black circle surrounded by wispy white light against a navy background" src="https://images.theconversation.com/files/582669/original/file-20240318-16-fmoksh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582669/original/file-20240318-16-fmoksh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=430&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582669/original/file-20240318-16-fmoksh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=430&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582669/original/file-20240318-16-fmoksh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=430&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582669/original/file-20240318-16-fmoksh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=540&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582669/original/file-20240318-16-fmoksh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=540&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582669/original/file-20240318-16-fmoksh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=540&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">A total solar eclipse in 2015 over Svalbard, Norway, reveals the streaming shapes in the solar wind pillars.</span>
<span class="attribution"><span class="source">(M. Druckmüller, S. Habbal, P. Aniol, P. Štarha)</span></span>
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<h2>Photography and astrophysics</h2>
<p>The parallel development of photography also helped <a href="https://history.aip.org/exhibits/cosmology/tools/tools-spectroscopy.htm">astronomy to turn into the science of astrophysics</a>, and the sun was an ideal first target for early instruments due to being very bright. </p>
<p>During the solar eclipse of 1868, emissions like the bright red known to be <a href="https://skyandtelescope.org/observing/guide-to-observing-the-sun-in-h-alpha092321050923/">from hydrogen were observed</a>. But when this light was broken down with a spectroscope, it also showed a yellow light that had never been observed on Earth. </p>
<p>This was determined to be a new element, named for its association with the sun (Greek <em>helios</em>). Only in 1895 was helium found on Earth, and in the strangest of places: <a href="https://www.smithsonianmag.com/history/how-scientists-discovered-helium-first-alien-element-1868-180970057/">radioactive ores</a>. </p>
<p>Almost all helium now used on Earth comes from natural gas fields, where it is trapped as it comes up from uranium and other decaying radioactive ores. The helium in the sun later became strong evidence for the Big Bang, in which the first nuclei, which were hydrogen, quickly underwent nuclear fusion to produce helium, but its discovery in the sun set the stage for expecting new elements there.</p>
<h2>A new mystery</h2>
<p>Once spectroscopy developed further in the late 19th century, indeed another mystery arose. Many elements had been discovered on Earth and put in systematic order by Russian chemist Dmitri Mendeleev as the “<a href="https://pubchem.ncbi.nlm.nih.gov/periodic-table">periodic table</a>.”</p>
<p>Surprisingly, many elements were also detected in solar spectra, usually when they absorbed specific wavelengths from the pure light coming from deep layers in the sun, <a href="https://imagine.gsfc.nasa.gov/science/toolbox/spectra1.html">leaving absorption lines</a>. Although the sun is made mostly of hydrogen and helium, these are not prominent in its spectrum. </p>
<p>However, in the corona, completely unknown lines were found. Following the lead of helium, it was felt that the sun must contain an element never observed on Earth, <a href="https://sunearthday.nasa.gov/2006/locations/coronium.php">promptly dubbed coronium</a>. Only in the 1940s was it realized that the emissions actually came from familiar elements, including iron. These were not initially recognized due to being highly stripped of the normal number of electrons going around their nuclei (normally 26 in iron), indicating extreme temperatures that rip atoms apart. </p>
<p>Even stranger, the further out one observed from the sun, the hotter the corona became.</p>
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<a href="https://images.theconversation.com/files/582445/original/file-20240318-20-t6q0rt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a black circle surrounded by wisps of red and green" src="https://images.theconversation.com/files/582445/original/file-20240318-20-t6q0rt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582445/original/file-20240318-20-t6q0rt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=441&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582445/original/file-20240318-20-t6q0rt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=441&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582445/original/file-20240318-20-t6q0rt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=441&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582445/original/file-20240318-20-t6q0rt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=554&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582445/original/file-20240318-20-t6q0rt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=554&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582445/original/file-20240318-20-t6q0rt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=554&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">The 2015 eclipse imaged in the light given off by highly ionized iron. The red indicates a temperature about one million degrees C, green about two million degrees C.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.3847/2041-8213/abe775">(SOURCE)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>Solar winds and weather</h2>
<p>In the late 1950s, the physicist Eugene Parker found that such high temperatures for the solar corona meant that it could not be static: it had to <a href="https://news.uchicago.edu/explainer/what-is-solar-wind">be blowing off into space</a>. This prediction was verified by <a href="http://www.phy6.org/Education/whsolwi.html">spacecraft measurements in 1959</a>. </p>
<p>Since then, we have known that there is a solar wind, and that the magnetic field shown by coronal structures is carried off into space with it. The solar wind can bring energy to Earth, which penetrates near us when the magnetic field is opposed to that of our planet, bringing auroras and potentially hazardous “<a href="https://theconversation.com/space-weather-is-difficult-to-predict-with-only-an-hour-to-prevent-disasters-on-earth-159895">space weather</a>.”</p>
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Read more:
<a href="https://theconversation.com/larger-and-more-frequent-solar-storms-will-make-for-potential-disruptions-and-spectacular-auroras-on-earth-219183">Larger and more frequent solar storms will make for potential disruptions and spectacular auroras on Earth</a>
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<p>NASA’s <a href="https://science.nasa.gov/mission/parker-solar-probe/">Parker Solar Probe</a> is now nearing the inner regions of the corona, still trying to determine the exact origins of the solar wind. Parker, who passed away in 2022, saw initial results from this spacecraft trying to find exactly how the outrageously hot corona propels the solar wind. </p>
<p>Meanwhile, April 8 is a rare opportunity to safely view the sun’s glorious super-heated corona.</p><img src="https://counter.theconversation.com/content/225866/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin Connors receives funding from NSERC. </span></em></p>The solar corona can be seen during the solar eclipse on April 8. Astronomers are still trying to figure out the mysteries of the corona, including why it’s so hot.Martin Connors, Professor of Space Science and Physics, Athabasca UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2191832023-12-28T19:34:18Z2023-12-28T19:34:18ZLarger and more frequent solar storms will make for potential disruptions and spectacular auroras on Earth<figure><img src="https://images.theconversation.com/files/564592/original/file-20231208-29-521tjc.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1669%2C1669&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A sunspot emitting a flare on the surface of the sun. </span> <span class="attribution"><a class="source" href="https://images.nasa.gov/details/PIA22645">(NASA/GSFC/Solar Dynamics Observatory)</a></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/larger-and-more-frequent-solar-storms-will-make-for-potential-disruptions-and-spectacular-auroras-on-earth" width="100%" height="400"></iframe>
<p>Bright auroras, with dancing lights in the sky, characterize the clear winter nights of northern Canada. Longer nights during the fall and winter also favour seeing more auroras, but the show is best outside of light-polluted cities. Impressive auroral events allowed bright auroras to be seen <a href="https://spaceweathergallery2.com/indiv_upload.php?upload_id=202170">as far south as the United States recently</a>. </p>
<p>Auroras are produced through the sun’s interaction with the Earth’s magnetic field. The number of auroras is increasing as <a href="https://www.swpc.noaa.gov/products/solar-cycle-progression">the sun’s activity becomes stronger</a>, approaching a solar maximum. </p>
<p>Perhaps surprisingly, the same space disturbances that cause auroras can affect our technologies.</p>
<p>In 1859, a geomagnetic storm — the largest in recorded history — disrupted technological systems, such as they were at the time, on Earth. Referred to as the “<a href="https://www.space.com/the-carrington-event">Carrington Event</a>” after Richard Carrington, the amateur astronomer who made the connection between a bright solar flare and subsequent auroral and magnetic effects. </p>
<p>That Sun-Earth link was slow to be accepted, but we now know that the Sun can trigger disturbances in near-Earth space, although it seems that events as large as that of 1859 are rare. </p>
<h2>Night visions</h2>
<p>Space is filled with thin hot gas called plasma that <a href="https://svs.gsfc.nasa.gov/14299/">carries magnetic fields</a>. The Earth, in the sun’s outer atmosphere, is surrounded by hot magnetic plasma which rushes past us at speeds of several hundred kilometres per second <a href="https://www.nasa.gov/solar-system/parker-solar-probe-and-the-birth-of-the-solar-wind/">in a flow called the solar wind</a>.</p>
<p>The sun is so massive that loss of the solar wind has a negligible effect on it, but Earth by comparison is a mere speck, three parts in a million as massive. <a href="https://www.nasa.gov/image-article/earths-magnetosphere-3/">Earth has a magnetic field</a>, which protects us from the solar onslaught, but is pushed back by it as well.</p>
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<a href="https://images.theconversation.com/files/564595/original/file-20231209-17-dta2j1.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a blue ball of light" src="https://images.theconversation.com/files/564595/original/file-20231209-17-dta2j1.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564595/original/file-20231209-17-dta2j1.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564595/original/file-20231209-17-dta2j1.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564595/original/file-20231209-17-dta2j1.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564595/original/file-20231209-17-dta2j1.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564595/original/file-20231209-17-dta2j1.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564595/original/file-20231209-17-dta2j1.gif?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>
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<span class="caption">These active regions may dramatically flare up in X-ray intensity, affecting Earth’s upper atmosphere and making a hazard for astronauts.</span>
<span class="attribution"><span class="source">(Solar Dynamics Observatory/NASA)</span></span>
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<p>Under certain conditions, energy can flow into the near-Earth region from the solar wind, largely building up on the opposite side from the sun in a comet-like “<a href="https://www.jstor.org/stable/24975910">magnetotail</a>.”</p>
<p>This can become unstable if too much energy builds up, blasting particles into the nightside atmosphere to light up auroras. This explains why auroras are seen at night: not only is it dark, but the sun’s energy takes an indirect route by first being stored in the magnetotail.</p>
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<figcaption><span class="caption">A NASA video explaining the magnetosphere.</span></figcaption>
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<p>The dancing auroras can also generate magnetic fields, which are strong enough to be detected by a compass, as discovered nearly 300 years ago by <a href="https://www.britannica.com/biography/Anders-Celsius">Swedish astronomer Anders Celsius</a>.</p>
<p>If the magnetic fields change rapidly, they can affect large regions of the Earth, building up to cause problems for power networks. This notably happened in North America in 1989, on the “<a href="https://spaceweatherarchive.com/2021/03/12/the-great-quebec-blackout">day the sun brought darkness</a>.”</p>
<h2>Solar cycles</h2>
<p>Italian astronomer Galileo studied sunspots in a systematic way in <a href="http://galileo.rice.edu/sci/observations/sunspots.html">the early 1600s</a>. About 300 years later, American astronomer George Hale showed that sunspots had intense magnetic fields, <a href="https://www2.hao.ucar.edu/education/scientists/george-ellery-hale-1868-1938">several thousand times stronger than Earth’s</a>. </p>
<p>In the 400 years since Galileo’s observations, we have found that the number of sunspots varies dramatically over <a href="https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle">an 11-year long cycle</a>. But it is only recently, in the Space Age, that we can relate its effects on Earth.</p>
<h2>Energy storage</h2>
<p>Magnetic fields store energy, and sometimes, as in Earth’s magnetotail or near sunspots, this energy can be changed to other forms. In the strong fields of sunspots, it can be released as X-rays in <a href="https://www.youtube.com/watch?v=64CTIrWBGTc">rapid, unpredictable flares</a>. </p>
<p>Sunspots and flares are near the surface or light-emitting layer of the sun, but <a href="https://www.swpc.noaa.gov/news/strongest-solar-flare-solar-cycle-25">material can escape from the sun’s strong gravity field</a>. Blobs of gas — <a href="https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections">coronal mass ejections</a> — can be hurtled into space. Some small fraction of these are shot out toward Earth, and auroras and their magnetic effects occur when they reach Earth’s atmosphere. They can also cause intensification of our radiation belts in ways that <a href="https://doi.org/10.1511/2014.110.374">can damage satellites</a>.</p>
<p>Counting sunspots on the sun’s surface allows us to get a general idea of what space disturbances may occur as the solar cycle progresses. Similarly, on Earth we can follow the seasons and have a general idea of what storms are likely. In both cases, however, exact prediction is difficult.</p>
<h2>Space weather forecasts</h2>
<p>From long-term trends, it was expected that the upcoming solar maximum would be small, as indeed <a href="https://doi.org/10.1051/swsc/2020060">the one that peaked in 2014 was</a>. However, in this, <a href="https://www.nasa.gov/news-release/solar-cycle-25-is-here-nasa-noaa-scientists-explain-what-that-means/">the following solar cycle</a>, we have already exceeded predicted numbers of sunspots and had large magnetic storms, so predictions may need to be revised upward. </p>
<p>Although direct measurement of incoming disturbances by satellites in the solar wind gives us only about an hour’s warning of stormy space weather, we can also predict a bit further in advance by watching sunspots rotate into view as the sun turns. </p>
<p>One solar rotation takes about as long as it does for the moon to go around Earth, that is to say, a month. So if a particular sunspot brings lots of activity, it likely will repeat in about a month.</p>
<h2>Rare storms</h2>
<p>The strongest flare of <a href="https://www.swpc.noaa.gov/news/sunspot-region-produces-x28-flare-largest-sep-10-2017">Solar Cycle 25 so far occurred on Dec. 14</a>, and was the most powerful eruption the sun has produced <a href="https://www.nasa.gov/missions/goes/september-2017s-intense-solar-activity-viewed-from-space">since the great storms of September 2017</a>.</p>
<p>Large solar storms are rare, but we must calmly prepare for possible space weather impacts that should maximize in a few years. We must be creative, since space weather effects can bring surprises. In 2022, unexpected heating of the atmosphere caused <a href="https://www.space.com/spacex-starlink-satellite-loss-space-weather-forecast">multiple satellite losses</a>. </p>
<p>As our knowledge of space physics steadily improves, so too will the new science of space weather prediction, allowing us to protect our technological assets. </p>
<p>In the meantime, we can look forward to spectacular auroras that should come as we near the 2025 solar maximum, with only measured and reasonable amounts of worry about the potential impacts of space weather.</p><img src="https://counter.theconversation.com/content/219183/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin Gerard Connors receives funding from Canada's NSERC. </span></em></p>The sun is expected to reach its solar maximum in 2025. Recent auroras suggest that the maximum may be bigger than predicted.Martin Connors, Professor of Space Science and Physics, Athabasca UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2099552023-08-14T18:42:58Z2023-08-14T18:42:58ZThis solar cycle, the sun’s activity is more powerful and surprising than predicted<figure><img src="https://images.theconversation.com/files/541795/original/file-20230808-15-85ytq4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1920%2C1080&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A coronal mass ejection on the solar surface.</span> <span class="attribution"><span class="source">(NASA/GSFC/SDO)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/this-solar-cycle-the-suns-activity-is-more-powerful-and-surprising-than-predicted" width="100%" height="400"></iframe>
<p>What do you feel when you see the aurora? </p>
<p>Otherwise known as the northern or southern lights, an aurora is light emitted by upper atmospheric particles as they interact with energized ones <a href="https://superdarn.ca/tutorials-11">from the magnetosphere</a>.</p>
<p>It’s an awe-inspiring and otherworldly event that those living at high latitudes can experience often. In <a href="https://creeliteracy.org/2018/05/01/northern-lights-creesimonsays/">Cree and Ojibwe teachings</a>, the northern lights are ancestral spirits who remain and communicate from the sky. </p>
<p>To scientists, the aurora is an infinitely complex amalgamation of <a href="https://www.nasa.gov/ionosphere">ionospheric</a> dynamics, a manifestation of Earth’s intrinsic connection to the sun. To industry, it’s a risk factor.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&rect=0%2C2%2C936%2C524&q=45&auto=format&w=1000&fit=clip"><img alt="green lights ribbon in the sky above powerlines" src="https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&rect=0%2C2%2C936%2C524&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540229/original/file-20230731-17-9pbazi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&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 aurora borealis seen above the Saskatoon SuperDARN space weather radar.</span>
<span class="attribution"><span class="source">(A. Reimer)</span></span>
</figcaption>
</figure>
<h2>The Starlink destruction event</h2>
<p>In February 2022, <a href="https://www.bbc.com/news/world-60317806">SpaceX launched 49 Starlink internet satellites into a low-Earth orbit (LEO)</a>. This was the 36th Starlink launch that SpaceX had carried out, and one that they anticipated to go off without a hitch, just like the 35 before. </p>
<p>On launch day, a <a href="https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections">coronal mass ejection</a> — a large burst of plasma expelled from the sun — struck Earth. It caused a geomagnetic storm in the atmosphere between around 100 and 500 kilometres in altitude, the target range for Starlink. </p>
<p>This event injected an immense amount of electromagnetic energy straight into Earth’s upper atmosphere. It produced <a href="https://www.youtube.com/watch?v=q_GYySXTtio">beautiful auroral displays</a>, but the energy also increased the density of the air. A higher air density typically isn’t a big deal for LEO satellites, because it’s already extremely low at usual operational altitudes (upwards of 400 kilometres). </p>
<p>Starlink, however, was initially <a href="https://doi.org/10.1029/2022SW003074">launched into an altitude of 210 kilometres</a>. That’s much closer to Earth, with an exponentially higher air density. Thirty-eight out of those 49 initial launch satellites were subsequently lost due to atmospheric drag from the dense atmosphere, <a href="https://doi.org/10.1051/swsc/2022034">pulling them back to Earth</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/mUlAz_Oxv4Q?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Starlink satellites burning up in the atmosphere over Puerto Rico, Feb. 7, 2022.</span></figcaption>
</figure>
<h2>Surprising solar cycle</h2>
<p>The sun undergoes a cycle — an 11-year one, to be exact — from which its activity increases and decreases periodically. At the peak of a cycle, we see more sunspots on the solar surface, more radiation emitted, and more solar flares. Geomagnetic storms like the one that caused the Starlink destruction event are a relatively common occurrence, especially when the sun reaches the peak of its 11-year cycle of strengthening and weakening activity. </p>
<p>In the previous cycle, which ended in 2019 (the 24th tracked cycle since 1755), <a href="https://doi.org/10.1016/j.asr.2022.10.033">there were 927 storms classed as moderate or weak alone</a> — an average of one every five or so days. </p>
<p>We’re currently four years into solar cycle 25, but this one has already proven surprising. The maximum activity of the 25th cycle was predicted to occur in 2025, but solar activity has already exceeded that. This means we’ve been seeing more geomagnetic storms, more auroral displays (and at lower latitudes than usual) and, potentially, more hazardous conditions for LEO satellites.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A plotted graph showing solar cycle sunspots" src="https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=221&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=221&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=221&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=278&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=278&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540308/original/file-20230731-23-cwg668.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=278&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Solar activity as the number of sunspots visible on the solar surface. The number of sunspots seen is already considerably higher than what is expected from the solar maximum, two years ahead of schedule.</span>
<span class="attribution"><a class="source" href="https://www.swpc.noaa.gov/products/solar-cycle-progression">(National Oceanic and Atmospheric Administration)</a></span>
</figcaption>
</figure>
<h2>Space weather — the unseen force of nature</h2>
<p>If geomagnetic storms are so common, why don’t they cause more issues? <a href="https://www.maine.gov/mema/maine-prepares/preparedness-library/geomagnetic-storms">The reality is that they do</a>, but the consequences are much less obvious than satellites burning up in the atmosphere.</p>
<p>When space weather energy enters Earth’s upper atmosphere, for example, the ionospheric composition changes in addition to the air getting denser. High-frequency, or “shortwave,” radio communication depends on a predictable ionosphere to broadcast long distances. </p>
<p>Geomagnetic storms that affect ionospheric composition can cause <a href="https://doi.org/10.1029/2018SW002008">radio blackouts</a>, such as a <a href="https://www.space.com/x-class-solar-flare-radio-blackout-august-2023">disruption in North America on Aug. 7</a>. Even minor storms can cause the degradation of radio signals used in military and maritime systems, aviation communication or ham radio. </p>
<p>Extreme storms can cause radio blackouts lasting hours, and for an entire side of the globe. Storms that big can also cause more discernible problems, such as the nine-hour <a href="http://www.hydroquebec.com/learning/notions-de-base/tempete-mars-1989.html">electricity outage experienced by Hydro-Québec in 1989</a>.</p>
<h2>Space weather warning systems</h2>
<p>It’s not all doom and disintegrating rockets, however. We can detect when a solar flare leaves the surface of the sun and predict roughly when it will affect the Earth, giving forewarning to certain types of storms and <a href="https://www.aurorawatch.ca/">chances to see the aurora</a>.</p>
<p>For many storms however, there is very little or no predictive capability because it depends on how the Earth’s magnetic field interacts with the solar wind, which is harder to see. </p>
<p>Nowcasting — using real-time data to understand conditions as they occur — is one of our best tools. With instruments such as ground-based radar and magnetometers on satellites, <a href="https://doi.org/10.1029/2023GL103733">we can estimate the electromagnetic space weather energy entering the atmosphere almost instantaneously</a>. </p>
<p>As for why SpaceX lost satellites in February 2022 during a minor geomagnetic storm, that was just a matter of timing. The loss of the satellites, however, is a stunning reminder of the power of the universe we live in.</p><img src="https://counter.theconversation.com/content/209955/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Billett receives funding from the European Space Agency and the Natural Sciences and Engineering Research Council of Canada. </span></em></p>We’re currently a few years into the 25th studied solar cycle. An 11-year period of sun activity, this solar cycle is more active than previously expected.Daniel Billett, Postdoctoral Fellow in Space Physics, University of SaskatchewanLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2045462023-05-24T13:07:12Z2023-05-24T13:07:12ZThe Tonga volcano eruption caused a ‘super bubble’ in Earth’s ionosphere, disrupting satellite navigation<figure><img src="https://images.theconversation.com/files/523693/original/file-20230501-26-bkhhsn.png?ixlib=rb-1.1.0&rect=57%2C3%2C2353%2C1415&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">GOES-18 image of Hunga Tonga Volcano. </span> <span class="attribution"><a class="source" href="https://www.space.com/tonga-underwater-volcano-stunning-eruption-from-space-video">NOAA</a></span></figcaption></figure><p>With technology increasingly embedded in our everyday lives, it is becoming more important to understand space weather and its impacts on tech.</p>
<p>When one hears “<a href="https://www.abc.net.au/contentsales/programsandgenres/solar-storms/14089696">space weather</a>”, one typically thinks of huge explosions on the Sun – coronal mass ejections hurled towards Earth, creating <a href="https://theconversation.com/what-are-auroras-and-why-do-they-come-in-different-shapes-and-colours-two-experts-explain-202618">beautiful displays of aurora</a>.</p>
<p>However, not all space weather starts at the Sun. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/523686/original/file-20230501-1802-ewcv53.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523686/original/file-20230501-1802-ewcv53.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523686/original/file-20230501-1802-ewcv53.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523686/original/file-20230501-1802-ewcv53.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523686/original/file-20230501-1802-ewcv53.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523686/original/file-20230501-1802-ewcv53.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523686/original/file-20230501-1802-ewcv53.gif?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">Satellite imagery of Hunga Tonga Volcano eruption.</span>
<span class="attribution"><span class="source">NASA Earth Observatory image by Joshua Stevens using GOES imagery courtesy of NOAA and NESDIS</span></span>
</figcaption>
</figure>
<p>The <a href="https://theconversation.com/why-the-volcanic-eruption-in-tonga-was-so-violent-and-what-to-expect-next-175035">volcanic eruption in Tonga</a> in January 2022 was so large, it created waves in the upper atmosphere that constituted their own form of space weather.</p>
<p>It was one of the largest explosions in modern history and impacted GPS across Australia and Southeast Asia. As we describe in our new study in the journal <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023SW003476">Space Weather</a>, the eruption caused a super “plasma bubble” over northern Australia that lasted for hours.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-year-on-we-know-why-the-tongan-eruption-was-so-violent-its-a-wake-up-call-to-watch-other-submarine-volcanoes-175734">A year on, we know why the Tongan eruption was so violent. It's a wake-up call to watch other submarine volcanoes</a>
</strong>
</em>
</p>
<hr>
<h2>A truly global positioning system</h2>
<p>While most people <a href="https://www.ga.gov.au/scientific-topics/positioning-navigation/positioning-australia/about-the-program">have a GPS</a> (global positioning system) receiver on their devices (such as a satnavs and smartphones), not many know how GPS actually works.</p>
<p>In essence, our devices listen to radio signals transmitted by satellites orbiting Earth. Using those signals, they calculate their location relative to the satellites, allowing us to orient ourselves and find that nearby pub or coffee shop.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FU_pY2sTwTA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How does GPS work?</span></figcaption>
</figure>
<p>The radio signals received by our devices are affected by Earth’s atmosphere (particularly the layer called the <a href="https://www.britannica.com/science/ionosphere-and-magnetosphere">ionosphere</a>), which degrades location accuracy. Common devices are only accurate to within tens of metres.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/527869/original/file-20230523-15-o16w99.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing the layers of Earth's atmosphere" src="https://images.theconversation.com/files/527869/original/file-20230523-15-o16w99.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/527869/original/file-20230523-15-o16w99.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=988&fit=crop&dpr=1 600w, https://images.theconversation.com/files/527869/original/file-20230523-15-o16w99.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=988&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/527869/original/file-20230523-15-o16w99.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=988&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/527869/original/file-20230523-15-o16w99.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1242&fit=crop&dpr=1 754w, https://images.theconversation.com/files/527869/original/file-20230523-15-o16w99.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1242&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/527869/original/file-20230523-15-o16w99.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1242&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Schematic of the Earth’s ionosphere, alongside the layers of the neutral atmosphere.</span>
<span class="attribution"><span class="source">American Geophysical Union</span></span>
</figcaption>
</figure>
<p>However, new and improving precise satellite positioning systems, used within the mining, agriculture and construction industries, can be accurate to within ten centimetres. The only catch is these systems need time to lock onto their location, and this can take thirty minutes or more.</p>
<p>This <a href="https://cgrsc.ca/resources/gnss-augmentation/precise-point-positioning-ppp/">precise satellite positioning</a> works by accurately modelling the errors caused by Earth’s ionosphere. But whenever the ionosphere becomes disturbed, it becomes complicated and difficult to model.</p>
<p>For instance, when a <a href="https://theconversation.com/massive-sunspots-and-huge-solar-flares-mean-unexpected-space-weather-for-earth-83677">geomagnetic storm</a> (a disturbance in the solar wind that impacts Earth’s magnetic field) takes place, the ionosphere becomes turbulent and radio waves travelling through it get scattered – like visible light that becomes bent and scattered when looking down into a lake in choppy conditions.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-tonga-volcanic-eruption-has-revealed-the-vulnerabilities-in-our-global-telecommunication-system-175048">The Tonga volcanic eruption has revealed the vulnerabilities in our global telecommunication system</a>
</strong>
</em>
</p>
<hr>
<h2>A volcanic disruption</h2>
<p><a href="https://www.nature.com/articles/s41586-022-05012-5">Recent studies</a> have shown the Hunga Tonga-Hunga Ha'apai volcano eruption caused choppy conditions in the ionosphere that lasted a few days. The size of the waves it generated in the ionosphere were similar in size to those created by geomagnetic storms.</p>
<p>While these waves influenced GPS data around the world for days after the eruption, their impact on positioning was rather limited in comparison to another type of disturbance in the ionosphere – a “super plasma bubble” that formed in the wake of the eruption.</p>
<p>The ionosphere is a layer of Earth’s atmosphere at altitudes of approximately 80–800km. It comprises gas with lots of electrically charged particles, which makes it a “<a href="https://scied.ucar.edu/learning-zone/sun-space-weather/plasma">plasma</a>”. </p>
<p>In turn, equatorial plasma bubbles are plasma disturbances in the ionosphere that naturally occur at nighttime above low-latitude regions. </p>
<p>Such plasma bubbles occur regularly. They form due to a phenomenon called the “generalised Rayleigh-Taylor instability”. It is similar to what happens when a heavy fluid sits on top of a less heavy fluid, and blobs of this lighter fluid rise up into the heavy fluid in the form of “bubbles” (see video below).</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/bW4526vHnY0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">“Classical” Rayleigh-Taylor instability in fluids.</span></figcaption>
</figure>
<p>When it comes to disturbances in the ionosphere however, the plasma is also controlled by magnetic and electric fields.</p>
<p>As they rise, plasma bubbles form strangely shaped structures that resemble cacti or inverted tree roots. Due to Earth’s magnetic field, these structures fan out as the bubble grows above the equator.</p>
<p>The result is that higher altitude bubbles reach higher latitudes as well. Typically, plasma bubbles reach a few hundred kilometres above the equator, reaching latitudes between 15 and 20 degrees to the north and south.</p>
<figure class="align-center ">
<img alt="Bubbles and super bubbles in the ionosphere" src="https://images.theconversation.com/files/524326/original/file-20230504-15-erqg5i.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524326/original/file-20230504-15-erqg5i.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524326/original/file-20230504-15-erqg5i.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524326/original/file-20230504-15-erqg5i.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524326/original/file-20230504-15-erqg5i.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524326/original/file-20230504-15-erqg5i.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524326/original/file-20230504-15-erqg5i.gif?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">Simulation showing the size and extent of a normal-size plasma bubble (left) next to that of the super bubble that reached above Northeastern Australia (right). The pink shading is the projection of the bubbles onto the map.</span>
<span class="attribution"><span class="source">Rezy Pradipta, Author provided</span></span>
</figcaption>
</figure>
<h2>A rare bubble above Australia</h2>
<p><a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL099798">Scientists detected</a> a <a href="https://www.nature.com/articles/s41598-023-33603-3">super plasma bubble</a> above Southeast Asia shortly after the Tonga eruption. It’s estimated to be similar in size to previously reported <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2006GL027512">rare super bubbles</a>.</p>
<p>Earth’s magnetic field carried this disturbance south, where it lingered for a few hours above Townsville in northeastern Australia.</p>
<p>To date, this is the farthest south any plasma bubble has been observed over Australia. While very rare, such super bubbles are known to have taken place over northern Australia, but they haven’t been directly observed before this event.</p>
<p>A roll-out of GPS stations across northern Australia has only recently made this type of observation possible.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523682/original/file-20230501-14-b62vgb.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/523682/original/file-20230501-14-b62vgb.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523682/original/file-20230501-14-b62vgb.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523682/original/file-20230501-14-b62vgb.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523682/original/file-20230501-14-b62vgb.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523682/original/file-20230501-14-b62vgb.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523682/original/file-20230501-14-b62vgb.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523682/original/file-20230501-14-b62vgb.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Disturbance in the GPS signals due to the ionosphere following the eruption.</span>
<span class="attribution"><span class="source">Brett Carter, Author provided</span></span>
</figcaption>
</figure>
<p>It is understood waves from the volcano eruption disturbed the winds in the upper atmosphere, altering the flow of plasma in the ionosphere and giving rise to the super plasma bubble.</p>
<p>Our study has found the bubble caused significant delays in the use of precise GPS across northern Australia and Southeast Asia. In some cases, getting a lock on the GPS location took over five hours longer due to the plasma bubble.</p>
<p>While we understand a lot about the ionosphere, our ability to predict its disturbances is still limited. Having more GPS stations is not only beneficial for improving positioning and navigation, it also fills gaps in monitoring the ionosphere. </p>
<p>The Tonga eruption was far from a typical “space weather” event caused by the Sun. But its impact on the upper atmosphere and GPS highlights the importance of understanding how the environment impacts the technologies we rely on.</p><img src="https://counter.theconversation.com/content/204546/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brett Carter is an Editor of the American Geophysical Union journal Space Weather. He receives funding from the Australian Research Council, SmartSat CRC and FrontierSI. He is also a member of the Australian Institute of Physics and the American Geophysical Union.</span></em></p><p class="fine-print"><em><span>Rezy Pradipta receives funding from the Federal Aviation Administration (FAA), National Aeronautics and Space Administration (NASA), and United States Air Force Office of Scientific Research (AFOSR). He is affiliated with the American Geophysical Union (AGU).</span></em></p><p class="fine-print"><em><span>Suelynn Choy receives funding from the CRC for Spatial Information, FrontierSI, Australian Research Council, SmartSat CRC and industry funding.</span></em></p>The eruption was so large, it created its own space weather and satellite technology disruptions – here’s how.Brett Carter, Associate Professor, RMIT UniversityRezy Pradipta, Senior Research Scientist, Boston CollegeSuelynn Choy, ProfessorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2026182023-03-29T04:32:17Z2023-03-29T04:32:17ZWhat are auroras, and why do they come in different shapes and colours? Two experts explain<figure><img src="https://images.theconversation.com/files/518083/original/file-20230329-24-p4501h.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3000%2C1998&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/LtnPejWDSAY">Lightscape / Unsplash</a></span></figcaption></figure><p>Over millennia, humans have observed and been inspired by beautiful displays of light bands dancing across dark night skies. Today, we call these lights the aurora: the aurora borealis in the northern hemisphere, and the aurora australis in the south.</p>
<p>Nowadays, we understand auroras are caused by charged particles from Earth’s magnetosphere and the solar wind colliding with other particles in Earth’s upper atmosphere. Those collisions excite the atmospheric particles, which then release light as they “relax” back to their unexcited state. </p>
<p>The colour of the light corresponds to the release of discrete chunks of energy by the atmospheric particles, and is also an indicator of how much energy was absorbed in the initial collision.</p>
<p>The frequency and intensity of auroral displays is related to activity on the Sun, which follows an 11-year cycle. Currently, we are approaching the next maximum, which is <a href="https://www.weather.gov/news/201509-solar-cycle">expected in 2025</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/sN5goxeTfjc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Fox Fires, a short film inspired by the Finnish folk tale of the aurora borealis.</span></figcaption>
</figure>
<h2>Connections to the Sun</h2>
<p>Such displays have long been documented by peoples throughout <a href="http://www.ewebtribe.com/NACulture/articles/aurora.html">North America</a>, Europe, <a href="https://www.smithsonianmag.com/smart-news/evidence-of-earliest-candidate-aurora-found-in-ancient-chinese-texts-180979979/">Asia</a> and <a href="https://education.riaus.org.au/cosmos-magazine-aurora-traditions-of-the-first-australians/">Australia</a>.</p>
<p>In the 17th century, scientific explanations for what caused the aurora began to surface. Possible explanations included air from Earth’s atmosphere rising out of Earth’s shadow to become sunlit (<a href="https://www.nasa.gov/mission_pages/themis/auroras/aurora_history.html">Galileo in 1619</a>) and light reflections from high-altitude ice crystals (<a href="https://pwg.gsfc.nasa.gov/polar/EPO/auroral_poster/aurora_all.pdf">Rene Descartes and others</a>). </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/do-the-northern-lights-make-sounds-that-you-can-hear-168032">Do the northern lights make sounds that you can hear?</a>
</strong>
</em>
</p>
<hr>
<p>In 1716, English astronomer Edmund Halley was the first to suggest a possible connection with Earth’s magnetic field. In 1731, a French philosopher named Jean-Jacques d'Ortous de Mairan noted a coincidence between the number of <a href="https://theconversation.com/giant-sunspot-returns-and-its-bigger-and-badder-than-ever-34002">sunspots</a> and aurora. He proposed that the aurora was connected with the Sun’s atmosphere. </p>
<p>It was here that the connection between activity on the Sun was linked with auroras here on Earth, giving rise to the areas of science now called “<a href="https://www.nasa.gov/mission_pages/sunearth/the-heliopedia">heliophysics</a>” and “<a href="https://spaceplace.nasa.gov/spaceweather/en/">space weather</a>”.</p>
<h2>Earth’s magnetic field as a particle trap</h2>
<p>The most common source of <a href="https://media.bom.gov.au/social/blog/1557/what-is-an-aurora/#:%7E:text=The%20colour%20emitted%20depends%20on,dark%20red%20or%20blue%20light.">aurora</a> is particles travelling within Earth’s <a href="https://www.nasa.gov/mission_pages/sunearth/multimedia/magnetosphere.html">magnetosphere</a>, the region of space occupied by Earth’s natural magnetic field. </p>
<p>Images of Earth’s magnetosphere typically show how the magnetic field “bubble” protects Earth from space radiation and repels most disturbances in the solar wind. However, what is not normally highlighted is the fact that Earth’s magnetic field contains its own population of electrically charged particles (or “plasma”). </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/DyuTyEw3etk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Model representation of Earth’s magnetic field interacting with the solar wind.</span></figcaption>
</figure>
<p>The magnetosphere is composed of charged particles that have escaped from Earth’s upper atmosphere and charged particles that have entered from the solar wind. Both types of particles are trapped in Earth’s magnetic field.</p>
<p>The motions of electrically charged particles are controlled by electric and magnetic fields. Charged particles gyrate around magnetic field lines, so when viewed at large scales magnetic field lines act as “pipelines” for charged particles in a plasma.</p>
<p>The Earth’s magnetic field is similar to a standard “dipole” magnetic field, with field lines bunching together near the poles. This bunching up of field lines actually alters the particle trajectories, effectively turning them around to go back the way they came, in a process called “magnetic mirroring”.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Sf1MGTD9xGY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">‘Magnetic mirroring’ makes charged particles bounce back and forth between the poles.</span></figcaption>
</figure>
<h2>Earth’s magnetosphere in a turbulent solar wind</h2>
<p>During quiet and stable conditions, most particles in the magnetosphere stay trapped, happily bouncing between the south and north magnetic poles out in space. However, if a disturbance in the solar wind (such as a <a href="https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections">coronal mass ejection</a>) gives the magnetosphere a “whack”, it becomes disturbed. </p>
<p>The trapped particles are accelerated and the magnetic field “pipelines” suddenly change. Particles that were happily bouncing between north and south now have their bouncing location moved to lower altitudes, where Earth’s atmosphere becomes more dense.</p>
<p>As a result, the charged particles are now likely to collide with atmospheric particles as they reach the polar regions. This is called “particle precipitation”. Then, when each collision occurs, energy is transferred to the atmospheric particles, exciting them. Once they relax, they emit the light that forms the beautiful aurora we see.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1640474775754784768"}"></div></p>
<h2>Curtains, colours and cameras</h2>
<p>The amazing displays of aurora dancing across the sky are the result of the complex interactions between the <a href="https://www.nasa.gov/feature/goddard/2021/themis-researchers-find-standing-waves-at-edge-of-earth-magnetic-bubble">solar wind and the magnetosphere</a>. </p>
<p>Aurora appearing, disappearing, brightening and forming structures like curtains, swirls, picket fences and travelling waves are all visual representations of the invisible, ever-changing dynamics in Earth’s magnetosphere as it interacts with the solar wind.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1640084831668432896"}"></div></p>
<p>As these videos show, aurora comes in all sorts of <a href="https://aurorasaurus.org/learn#aurora-colors">colours</a>. </p>
<p>The most common are the greens and reds, which are both emitted by oxygen in the upper atmosphere. Green auroras correspond to altitudes close to 100 km, whereas the red auroras are higher up, above 200 km. </p>
<p>Blue colours are emitted by nitrogen – which can also emit some reds. A range of pinks, purples and even white light are also possible due to a mixture of these emissions.</p>
<p>The aurora is more brilliant in photographs because camera sensors are more sensitive than the human eye. Specifically, our eyes are less sensitive to colour at night. However, if the aurora is bright enough it can be quite a sight for the naked eye. </p>
<h2>Where and when?</h2>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/0xUF82rVljE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Catching aurora in the southern hemisphere.</span></figcaption>
</figure>
<p>Even under quiet space weather conditions, aurora can be very prominent at high latitudes, such as in <a href="https://allsky.gi.alaska.edu/">Alaska</a>, <a href="https://auroramax.com/live">Canada</a>, <a href="https://site.uit.no/spaceweather/data-and-products/tgo-all-sky-cameras/">Scandinavia</a> and <a href="http://polaris.nipr.ac.jp/%7Eacaurora/syoCDC/index.html">Antarctica</a>. When a space weather disturbance takes place, auroras can migrate to much lower latitudes to become visible across the continental <a href="https://www.youtube.com/watch?v=_Myo-0CLrck&t=2s">United States</a>, <a href="https://www.agenzianova.com/en/news/aurora-boreale-in-germania-video/">central Europe</a> and even <a href="https://twitter.com/Rosiebscorpio/status/1639180442053283840?s=20">southern</a> and <a href="https://twitter.com/perthobs/status/1639122431532216325?s=20">mainland Australia</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1640002469366202369"}"></div></p>
<p>The severity of the space weather event typically controls the range of locations where the aurora is visible. The strongest events are the most rare.</p>
<p>So, if you’re interested in hunting auroras, keep an eye on your local space weather forecasts (<a href="https://www.swpc.noaa.gov/">US</a>, <a href="https://www.sws.bom.gov.au/">Australia</a>, <a href="https://www.metoffice.gov.uk/weather/specialist-forecasts/space-weather">UK</a>, <a href="https://spaceweather.sansa.org.za/">South Africa</a> and <a href="https://swe.ssa.esa.int/current-space-weather">Europe</a>). There are also numerous space weather experts on social media and even aurora-hunting citizen science projects (such as <a href="https://www.aurorasaurus.org/">Aurorasaurus</a>) that you can contribute towards!</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/uRufGWOiWmI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A rare sighting of the aurora australis from central Australia, with Uluru in the foreground.</span></figcaption>
</figure>
<p>Get outside and witness one of nature’s true natural beauties – aurora, Earth’s gateway to the heavens.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fire-in-the-sky-the-southern-lights-in-indigenous-oral-traditions-39113">Fire in the sky: The southern lights in Indigenous oral traditions</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/202618/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brett Carter receives funding from the Australian Research Council, the SmartSat CRC and the Australian Department of Defence. He has also consulted for Chimu Adventures as part of their Southern Lights Flight tours. </span></em></p><p class="fine-print"><em><span>Elizabeth A. MacDonald receives funding from NASA and employed by NASA's Goddard Space Flight Center. The Aurorasaurus project receives funding from NASA and NSF. </span></em></p>The aurora is one of nature’s most spectacular sights, a dazzling glow in the upper atmosphere driven by space weather.Brett Carter, Associate Professor, RMIT UniversityElizabeth A. MacDonald, Space Physicist, NASALicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1775102022-03-02T13:28:17Z2022-03-02T13:28:17ZSolar storms can destroy satellites with ease – a space weather expert explains the science<figure><img src="https://images.theconversation.com/files/448971/original/file-20220228-13-1r7fc0y.jpg?ixlib=rb-1.1.0&rect=0%2C42%2C4096%2C4046&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Sun occasionally ejects large amounts of energy and particles into space that can smash into Earth.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Coronal_mass_ejection_erupts_on_the_Sun,_31_August_2012.jpg#/media/File:Coronal_mass_ejection_erupts_on_the_Sun,_31_August_2012.jpg">NASA/GSFC/SDO via WikimediaCommons</a></span></figcaption></figure><p>On Feb. 4, 2022, SpaceX launched 49 satellites as part of Elon Musk’s Starlink internet project, <a href="https://www.cnbc.com/2022/02/09/spacex-losing-starlink-satellites-due-to-geomagnetic-space-storm.html">most of which burned up in the atmosphere days later</a>. The cause of this more than <a href="https://www.cnbc.com/2022/02/09/spacex-losing-starlink-satellites-due-to-geomagnetic-space-storm.html">US$50 million</a> failure was a geomagnetic storm caused by the Sun. </p>
<p>Geomagnetic storms occur when space weather hits and interacts with the Earth. Space weather is caused by fluctuations within the Sun that blast electrons, protons and other particles into space. <a href="https://scholar.google.com/citations?user=TdViV_sAAAAJ&hl=en&oi=ao">I study the hazards space weather poses to space-based assets</a> and how scientists can improve the models and prediction of space weather to protect against these hazards. </p>
<p>When space weather reaches Earth, it triggers many complicated processes that can cause a lot of trouble for anything in orbit. And engineers like me are working to better understand these risks and defend satellites against them.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/lOgIrDirDYY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Sun occasionally blasts huge amounts of particles into space during active events like solar flares and coronal mass ejections.</span></figcaption>
</figure>
<h2>What causes space weather?</h2>
<p>The Sun is always releasing a steady amount of charged particles into space. This is called the solar wind. Solar wind also carries with it the solar magnetic field. Sometimes, localized fluctuations on the Sun will <a href="https://www.swpc.noaa.gov/phenomena/solar-wind">hurl unusually strong bursts of particles in a particular direction</a>. If Earth happens to be in the path of the enhanced solar wind generated by one of these events and gets hit, you get a geomagnetic storm.</p>
<p>The two most common causes of geomagnetic storms are <a href="https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections">coronal mass ejections</a> – explosions of plasma from the surface of the Sun – and <a href="https://www.swpc.noaa.gov/news/coronal-hole-high-speed-streams-ch-hss">solar wind that escapes through coronal holes</a> – spots of low density in the Sun’s outer atmosphere.</p>
<p>The speed at which the ejected plasma or solar wind arrives at Earth is an important factor – the faster the speed, the stronger the geomagnetic storm. Normally, <a href="https://pwg.gsfc.nasa.gov/istp/nicky/cme-chase.html#:%7E:text=Near%20solar%20activity%20maximum%2C%20the,about%20400%20kilometers%20per%20second">solar wind travels at roughly 900,000 mph</a> (1.4 million kph). But strong solar events can release winds up to five times as fast.</p>
<p>The strongest geomagnetic storm on record was caused by a <a href="https://www.history.com/news/a-perfect-solar-superstorm-the-1859-carrington-event">coronal mass ejection in September 1859</a>. When the mass of particles hit Earth, they caused electrical surges in telegraph lines that shocked operators and, in some extreme cases, <a href="https://doi.org/10.1016/j.asr.2006.01.013">actually set telegraph instruments on fire</a>. Research suggests that if a geomagnetic storm of this magnitude hit Earth today, it would cause roughly <a href="https://www.history.com/news/a-perfect-solar-superstorm-the-1859-carrington-event">$2 trillion in damage</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/448952/original/file-20220228-15-qnx8er.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A drawing showing the Earth surrounded by a magnetic field with solar energy compressing one side." src="https://images.theconversation.com/files/448952/original/file-20220228-15-qnx8er.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448952/original/file-20220228-15-qnx8er.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=328&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448952/original/file-20220228-15-qnx8er.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=328&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448952/original/file-20220228-15-qnx8er.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=328&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448952/original/file-20220228-15-qnx8er.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=412&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448952/original/file-20220228-15-qnx8er.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=412&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448952/original/file-20220228-15-qnx8er.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=412&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 Earth’s magnetic field acts as a shield that absorbs most solar wind.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Magnetosphere_rendition.jpg#/media/File:Magnetosphere_rendition.jpg">NASA via WikimediaCommons</a></span>
</figcaption>
</figure>
<h2>A magnetic shield</h2>
<p>Emissions from the Sun, including the solar wind, would be incredibly dangerous to any life form unlucky enough to be directly exposed to them. Thankfully, Earth’s magnetic field does a lot to protect humanity.</p>
<p>The first thing solar wind hits as it approaches Earth is the magnetosphere. This region surrounding the Earth’s atmosphere is filled with plasma made of electrons and ions. It’s dominated by the planet’s strong magnetic field. When solar wind hits the magnetosphere, it transfers mass, energy and momentum into this layer. </p>
<p>The magnetosphere can absorb most of the energy from the everyday level of solar wind. But during strong storms, it can get overloaded and transfer excess energy to the upper layers of Earth’s atmosphere near the poles. This redirection of energy to the poles is what <a href="https://www.swpc.noaa.gov/phenomena/aurora">results in fantastic aurora events</a>, but it also causes changes in the upper atmosphere that can harm space assets.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/449002/original/file-20220228-15-1ec6d9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing the many layers of the atmosphere: the troposphere, from 0 to 12 km from Earth's surface, moving upward through the stratosphere, mesosphere, thermosphere and finally the exosphere, the layer from 700 to 190,000 km above Earth." src="https://images.theconversation.com/files/449002/original/file-20220228-15-1ec6d9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449002/original/file-20220228-15-1ec6d9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=500&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449002/original/file-20220228-15-1ec6d9h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=500&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449002/original/file-20220228-15-1ec6d9h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=500&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449002/original/file-20220228-15-1ec6d9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=628&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449002/original/file-20220228-15-1ec6d9h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=628&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449002/original/file-20220228-15-1ec6d9h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=628&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 different layers of Earth’s atmosphere are all affected by solar storms differently.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/cartoon-atmosphere-layers-card-poster-royalty-free-illustration/1064199092?adppopup=true">Bigmouse108 / iStock via Getty Images</a></span>
</figcaption>
</figure>
<h2>Dangers to what’s in orbit</h2>
<p>There a few different ways geomagnetic storms threaten orbiting satellites that serve people on the ground daily.</p>
<p>When the atmosphere absorbs energy from magnetic storms, it heats up and expands upward. This <a href="https://doi.org/10.1029/2005JA011274">expansion significantly increases the density of the thermosphere</a>, the layer of the atmosphere that extends from about 50 miles (80 kilometers) to roughly 600 miles (1,000 km) above the surface of the Earth. Higher density means <a href="https://www.swpc.noaa.gov/impacts/satellite-drag#:%7E:text=The%20drag%20force%20on%20satellites,were%20previously%20at%20lower%20altitudes">more drag, which can be a problem for satellites</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/448968/original/file-20220228-13-1wlbbd7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A satellite carrying a stack of Starlink satellites." src="https://images.theconversation.com/files/448968/original/file-20220228-13-1wlbbd7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448968/original/file-20220228-13-1wlbbd7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448968/original/file-20220228-13-1wlbbd7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448968/original/file-20220228-13-1wlbbd7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448968/original/file-20220228-13-1wlbbd7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448968/original/file-20220228-13-1wlbbd7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448968/original/file-20220228-13-1wlbbd7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Starlink satellites are released in batches, and 40 were destroyed in early February because of a geomagnetic storm.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Starlink_Mission_(47926144123).jpg#/media/File:Starlink_Mission_(47926144123).jpg">SpaceX via WikimediaCommons</a></span>
</figcaption>
</figure>
<p>This situation is exactly what led to the demise of the the SpaceX Starlink satellites in February. Starlink satellites are <a href="https://www.cnbc.com/2022/02/09/spacex-losing-starlink-satellites-due-to-geomagnetic-space-storm.html">dropped off by Falcon 9 rockets into a low-altitude orbit</a>, typically somewhere between 60 and 120 miles (100 and 200 km) above the Earth’s surface. The satellites then use onboard engines to slowly overcome the force of drag and raise themselves to their final altitude of approximately <a href="https://www.cnbc.com/2022/02/09/spacex-losing-starlink-satellites-due-to-geomagnetic-space-storm.html">350 miles (550 km)</a>. </p>
<p>The latest batch of Starlink satellites encountered a geomagnetic storm while still in very low-Earth orbit. Their engines could not overcome the <a href="https://www.cnbc.com/2022/02/09/spacex-losing-starlink-satellites-due-to-geomagnetic-space-storm.html">significantly increased drag</a>, and the satellites began slowly falling toward Earth and eventually burned up in the atmosphere.</p>
<p>Drag is just one hazard that space weather poses to space-based assets. The significant increase in high-energy electrons within the magnetosphere during strong geomagnetic storms means more electrons will penetrate the shielding on a spacecraft and accumulate within its electronics. This buildup of electrons can <a href="https://www.nasa.gov/vision/universe/solarsystem/killer_electrons.html">discharge in what is basically a small lightning strike</a> and damage electronics. </p>
<p>Penetrating radiation or charged particles in the magnetosphere – even during mild geomagnetic storms – can also <a href="https://www.cambridge.org/core/books/spacecraftenvironment-interactions/F722691656610F887D25CB66695DDE01#:%7E:text=Spacecraft%2DEnvironment%20Interactions%20is%20a,and%20for%20spacecraft%20system%20engineers">alter the output signal from electronic devices</a>. This phenomenon can cause errors in any part of a spacecraft’s electronics system, and if the error occurs in something critical, the entire satellite can fail. Small errors are common and usually fixable, but <a href="https://doi.org/10.1002/swe.20023">total failures, though rare, do happen</a>.</p>
<p>Finally, geomagnetic storms can disrupt the ability of satellites to communicate with Earth using radio waves. Many communications technologies, like GPS, for example, <a href="https://www.sciencedirect.com/topics/social-sciences/radio-waves#:%7E:text=GPS%20receivers%20use%20radio%20waves,a%20reference%20system%20for%20GPS.">rely on radio waves</a>. The atmosphere always <a href="https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=6431636">distorts radio waves by some amount </a>, so engineers correct for this distortion when building communication systems. But during geomagnetic storms, changes in the ionosphere – the charged equivalent of the thermosphere that spans roughly the same altitude range – will change how radio waves travel through it. The calibrations in place for a quiet atmosphere become wrong during geomagnetic storms.</p>
<p>This, for example, makes it difficult to lock onto GPS signals and can <a href="https://doi.org/10.1029/2018SW001940">throw off the positioning by a few meters</a>. For many industries – aviation, maritime, robotics, transportation, farming, military and others – GPS positioning errors of a few meters are simply not tenable. Autonomous driving systems will require accurate positioning as well.</p>
<h2>How to protect against space weather</h2>
<p>Satellites are critically important for much of the modern world to function, and protecting space assets from space weather is an <a href="https://www.sworm.gov/">important area of research</a>. </p>
<p>Some of the risks can be minimized by <a href="https://doi.org/10.1038/s41598-021-99739-2">shielding electronics from radiation</a> or <a href="https://doi.org/10.1016/j.actaastro.2020.12.010">developing materials</a> that are more resistant to radiation. But there is only so much shielding that can be done in the face of a <a href="https://doi.org/10.1038/s41598-021-99739-2">powerful geomagnetic storm</a>.</p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>The ability to accurately forecast storms would make it possible to preemptively safeguard satellites and other assets to a certain extent by shutting down sensitive electronics or reorienting the satellites to be better protected. But while the modeling and forecasting of geomagnetic storms has significantly improved over the past few years, the projections are often wrong. The National Oceanic and Atmospheric Administration had warned that, following a coronal mass ejection, a <a href="https://www.space.com/sunspot-ar2936-solar-flare-cme-arrival-earth">geomagnetic storm was “likely” to occur</a> the day before or the day of the February Starlink launch. The mission went ahead anyway.</p>
<p>The Sun is like a child that often throws tantrums. It’s essential for life to go on, but its ever-changing disposition make things challenging.</p><img src="https://counter.theconversation.com/content/177510/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Piyush Mehta receives funding from the National Science Foundation and the National Aeronautics and Space Administration. He is affiliated with the National Aeronautics and Space Administration as a Special Government Employee and is a member of the NASA Space Weather Council. </span></em></p>Space weather can affect satellites in a number of different ways, from frying electronics to increasing drag in the atmosphere.Piyush Mehta, Assistant Professor of Mechanical and Aerospace Engineering, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1650002021-10-21T19:12:08Z2021-10-21T19:12:08ZCurious Kids: Why are the northern lights only spotted near the North Pole?<figure><img src="https://images.theconversation.com/files/427864/original/file-20211021-15-1x7qi1g.jpg?ixlib=rb-1.1.0&rect=0%2C12%2C8075%2C2864&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Aurora Australis, or Southern Lights, reflected in the water.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>Curious Kids is a series for children of all ages. Have a question you’d like an expert to answer? Send it to <a href="mailto:curiouskidscanada@theconversation.com">CuriousKidsCanada@theconversation.com</a>.</em></p>
<blockquote>
<p><strong>Why are the northern lights only spotted at areas around the poles? — Naba, 9, Oakville, Ont.</strong></p>
</blockquote>
<p>The northern lights are also called auroras, and they are regularly visible near Earth’s North and South Poles. They are a direct connection between the Earth and what’s happening on the sun.</p>
<p>Did you know that the sun has weather? But unlike Earth’s weather, the sun’s weather can affect the entire solar system! We call it space weather.</p>
<hr>
<p>
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Read more:
<a href="https://theconversation.com/solar-weather-has-real-material-effects-on-earth-118453">Solar weather has real, material effects on Earth</a>
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<p>The sun is constantly blowing a spray of tiny particles in all directions, called the solar wind. This wind isn’t made of air, like on Earth. It’s made of mostly hydrogen, and it’s blowing at hundreds of kilometres per second (this is more than a thousand times faster than hurricane-force wind on Earth). </p>
<p>This incredibly fast wind has been blowing on to the Earth for billions of years, so why hasn’t it blown away Earth’s air by crashing into us?</p>
<p>Fortunately, for living things like us, the Earth has a magnetic field, which causes the planet to act like a giant magnet in space and protects Earth from the solar wind. Earth’s magnetic field is what causes <a href="https://www.livescience.com/32732-how-does-a-compass-work.html">a compass to work</a>. <a href="https://www.steampoweredfamily.com/activities/how-to-make-a-compass/">The small magnet in a compass</a> aligns with Earth’s magnetic field and always points to Earth’s magnetic North Pole. Earth’s magnetic field is totally invisible to our eyes, but we can <a href="https://www.geomag.nrcan.gc.ca/mag_fld/default-en.php">measure it with magnets and other scientific instruments</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/o4FSg-90XlA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A NASA video showing how the Earth’s magnetic field protects from the solar wind.</span></figcaption>
</figure>
<p>The particles that make up the solar wind are deflected by Earth’s magnetic field, so they mostly pass around the Earth without crashing into us. But it’s not a perfect shield: because of the <a href="https://science.nasa.gov/science-news/news-articles/earths-magnetosphere">shape of Earth’s magnetic field</a>, close to the North and South Poles, a little bit of the solar wind can sometimes get through and crash directly into the Earth’s atmosphere.</p>
<p>This crash happens between very tiny particles at speeds much faster than a bullet, so the result is very different from than say, a car crash. Instead of throwing off smaller pieces or exploding, they emit light. The colours tell us about what type of atmospheric particle is being crashed into by the solar wind. Red and green are from oxygen collisions, and blue is from nitrogen.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/427892/original/file-20211021-24-1b9lal4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="the northern lights" src="https://images.theconversation.com/files/427892/original/file-20211021-24-1b9lal4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/427892/original/file-20211021-24-1b9lal4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/427892/original/file-20211021-24-1b9lal4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/427892/original/file-20211021-24-1b9lal4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/427892/original/file-20211021-24-1b9lal4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/427892/original/file-20211021-24-1b9lal4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/427892/original/file-20211021-24-1b9lal4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&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 northern lights as seen from Iceland.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
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<h2>Space weather</h2>
<p>Exactly what the auroras look like depends a bit on the state of Earth’s magnetic field and atmosphere, but more directly depends on space weather. Sometimes the sun produces a storm, called a <a href="https://www.swpc.noaa.gov/phenomena/solar-flares-radio-blackouts">solar flare</a> or a <a href="https://earthsky.org/space/what-are-coronal-mass-ejections/">coronal mass ejection</a>, when there are suddenly a lot more particles injected into the solar wind, making it stronger than usual. Because we have telescopes <a href="https://sohowww.nascom.nasa.gov/">in space</a> and <a href="http://obs.astro.ucla.edu/intro.html">on Earth</a> that carefully watch the sun for these storms, we usually have two to three days warning before a storm hits the Earth.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/space-weather-is-difficult-to-predict-with-only-an-hour-to-prevent-disasters-on-earth-159895">Space weather is difficult to predict — with only an hour to prevent disasters on Earth</a>
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<p>Typically, a solar storm will cause an impressive display of auroras only for people who live in the far north and south of the world, underneath the part of Earth’s magnetic field that can let the solar wind through. But sometimes, a really powerful storm can cause the auroras to be visible much closer to the equator. </p>
<p>When this happens, it means that a lot of the solar wind particles are crashing all over Earth’s atmosphere. It’s not dangerous to us directly because we’re protected from these fast-moving particles by Earth’s atmosphere. But astronauts who are above the atmosphere may have <a href="https://www.space.com/3247-astronauts-sleep-safety-solar-flare.html">to take shelter in a heavily shielded part of the space station</a>, and satellites can be temporarily shut down or even broken.</p>
<p>On very rare occasions, the auroras caused by a solar storm can be so powerful that <a href="https://www.nasa.gov/topics/earth/features/sun_darkness.html">electrical lines</a> on Earth can be damaged, causing many people to <a href="https://www.washingtonpost.com/news/capital-weather-gang/wp/2013/10/31/the-scary-halloween-solar-storm-of-2003-a-warning-for-todays-space-weather/">lose power</a>.</p>
<p>The sun has a cycle of storms: <a href="https://spaceplace.nasa.gov/solar-cycles/">it has more frequent storms every 11 years</a>, which is called the solar maximum. When the sun is near solar maximum, auroras are more likely to happen. The next solar maximum is <a href="https://www.nasa.gov/press-release/solar-cycle-25-is-here-nasa-noaa-scientists-explain-what-that-means">predicted to be in late 2024 or early 2025</a>, so we will have more and more auroras to watch over the next few years.</p>
<p>If you want to see auroras, you can check the <a href="https://spaceweather.com/">space weather forecast</a> every night just like you can check your local weather forecast every day.</p>
<p>In places close to the poles, where people have been watching auroras for as long as we’ve been human, <a href="https://newsinteractives.cbc.ca/longform/legends-of-the-northern-lights">many cultures understand the lights as a cosmic connection</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fire-in-the-sky-the-southern-lights-in-indigenous-oral-traditions-39113">Fire in the sky: The southern lights in Indigenous oral traditions</a>
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<p>A truly bright auroral display is an incredible experience. It’s a powerful reminder of connection between the Earth’s atmosphere, magnetic field and the sun, all of which are vitally important to life on Earth. </p>
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<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidscanada@theconversation.com">CuriousKidsCanada@theconversation.com</a>. Please tell us your name, age and the city where you live.</em>
<em>And since curiosity has no age limit — adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p>
<hr><img src="https://counter.theconversation.com/content/165000/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samantha Lawler receives funding from the Natural Sciences and Engineering Research Council of Canada.</span></em></p>A curious kid asks: Why are the northern lights only spotted at areas around the poles?Samantha Lawler, Assistant professor of astronomy, University of ReginaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1690272021-10-07T04:53:55Z2021-10-07T04:53:55ZForecasting space weather is hard. A new Australian satellite may help make it easier<figure><img src="https://images.theconversation.com/files/425153/original/file-20211007-27-1fxi6es.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2851%2C1556&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The CUAVA-1 satellite departs from the International Space Station.</span> <span class="attribution"><span class="source">JAXA</span></span></figcaption></figure><p>The Australian-made space weather satellite CUAVA-1 was deployed into orbit from the International Space Station on <a href="https://www.youtube.com/watch?v=UHbRKOzzvp0&t=1223s">Wednesday night</a>. <a href="https://cosmosmagazine.com/australia/australian-made-cubesats-blast-off-to-the-iss/">Launched to the space station</a> in August aboard a <a href="https://www.youtube.com/watch?v=CirCiSe96Yk&t=925s">SpaceX rocket</a>, a major focus of this shoebox-sized CubeSat is to study what radiation from the Sun does to Earth’s atmosphere and electronic devices.</p>
<p><a href="https://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html">Space weather</a> such as <a href="https://theconversation.com/massive-sunspots-and-huge-solar-flares-mean-unexpected-space-weather-for-earth-83677">solar flares</a> and changes in the solar wind affects Earth’s ionosphere (a layer of charged particles in the upper atmosphere). This in turn has an impact on <a href="https://www.sws.bom.gov.au/Category/Educational/Other%20Topics/Radio%20Communication/Intro_HF_Radio.pdf">long-distance radio communications</a> and the <a href="https://www.swpc.noaa.gov/impacts/satellite-drag">orbits of some satellites</a>, as well as creating fluctuations in the electromagnetic field that can wreak havoc with electronics in space and down to the ground. </p>
<p>The new satellite is the first designed and built by the Australian Research Council Training Centre for Cubesats, UAVs, and their Applications (or <a href="https://www.cuava.com.au/">CUAVA</a> for short). It carries payloads and technology demonstrators built by collaborators from the University of Sydney, Macquarie University, and UNSW-Sydney. </p>
<p>One of CUAVA-1’s aims is to help improve space weather forecasts, which are currently very limited. As well as its scientific mission, CUAVA-1 also represents a step towards the Australian Space Agency’s goal of <a href="https://publications.industry.gov.au/publications/advancing-space-australian-civil-space-strategy-2019-2028.pdf">growing the local space industry by 20,000 jobs by 2030</a>.</p>
<h2>Satellites and space weather</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/425198/original/file-20211007-15-jsspfy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/425198/original/file-20211007-15-jsspfy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=353&fit=crop&dpr=1 600w, https://images.theconversation.com/files/425198/original/file-20211007-15-jsspfy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=353&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/425198/original/file-20211007-15-jsspfy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=353&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/425198/original/file-20211007-15-jsspfy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=444&fit=crop&dpr=1 754w, https://images.theconversation.com/files/425198/original/file-20211007-15-jsspfy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=444&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/425198/original/file-20211007-15-jsspfy.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=444&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Exploded view of CUAVA-1 and its components and payloads. Tanned labels indicate Australian-made components.</span>
<span class="attribution"><span class="source">Xueliang Bai</span></span>
</figcaption>
</figure>
<p>While the Australian Space Agency was only formed in 2018, Australia has a <a href="https://theconversation.com/lost-in-space-australia-dwindled-from-space-leader-to-also-ran-in-50-years-83310">long history in satellite research</a>. In 2002, for example, <a href="https://www.nature.com/articles/40947">FedSat</a> was one of the first satellites in the world to carry a GPS receiver onboard. </p>
<p>Space-based GPS receivers today make it possible to routinely measure the atmosphere all around the world for weather monitoring and prediction. The Bureau of Meteorology and other weather forecasting agencies rely on <a href="https://www.gpsworld.com/ucar-system-boosts-gnss-data-for-weather-forecasting/">space-based GPS data</a> in their forecasting.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lost-in-space-australia-dwindled-from-space-leader-to-also-ran-in-50-years-83310">Lost in space: Australia dwindled from space leader to also-ran in 50 years</a>
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<hr>
<p>Space-based GPS receivers also make it possible to monitor the Earth’s ionosphere. From heights of about 80km to 1,000km, this layer of the atmosphere transitions from a gas of uncharged atoms and molecules to a gas of charged particles, both electrons and ions. (A gas of charged particles is also called a plasma.) </p>
<p>The ionosphere is the location of the <a href="https://www.youtube.com/watch?v=FpLd20_htF8&t=1s">beautiful auroral displays</a> that are common at high latitudes during moderate <a href="https://www.nasa.gov/mission_pages/sunearth/news/storms-on-sun.html#.VHaLDHVdXfE">geomagnetic storms</a>, or “bad space weather”, but there is much more to it.</p>
<p>The ionosphere can cause difficulties for satellite positioning and navigation, but it is also sometimes useful, such as when <a href="https://www.baesystems.com/en-aus/feature/seeing-over-the-horizon">ground-based radar</a> and radio signals can be bounced off it to scan or communicate over the horizon.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/425178/original/file-20211007-13-jrxwqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/425178/original/file-20211007-13-jrxwqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=463&fit=crop&dpr=1 600w, https://images.theconversation.com/files/425178/original/file-20211007-13-jrxwqd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=463&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/425178/original/file-20211007-13-jrxwqd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=463&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/425178/original/file-20211007-13-jrxwqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=581&fit=crop&dpr=1 754w, https://images.theconversation.com/files/425178/original/file-20211007-13-jrxwqd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=581&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/425178/original/file-20211007-13-jrxwqd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=581&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Technological and infrastructure affected by space weather events.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<h2>Why space weather is so hard to predict</h2>
<p>Understanding the ionosphere is an important part of operational space weather forecasting. We know the ionosphere becomes highly irregular during severe geomagnetic storms. It disrupts radio signals that pass through it, and creates surges of electric current in power grids and pipelines. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/P8jwTpG-26E?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What is space weather?</span></figcaption>
</figure>
<p>During severe <a href="https://media.bom.gov.au/social/blog/2454/space-weather-and-the-sun/">geomagnetic storms</a>, a large amount of energy is dumped into the Earth’s upper atmosphere near the north and south poles, while also changing currents and flows in the equatorial ionosphere.</p>
<p>This energy dissipates through the system, causing widespread changes throughout the upper atmosphere and altering high-altitude wind patterns above the equator hours later. </p>
<p>In contrast, X-rays and UV radiation from solar flares directly heat the atmosphere (above the ozone layer) above the equator and middle latitudes. These changes influence the amount of drag experienced in low-Earth orbit, making it difficult to predict the paths of satellites and space debris.</p>
<p>Even outside geomagnetic storms, there are “quiet-time” disturbances that affect <a href="https://theconversation.com/predicting-daily-space-weather-will-help-keep-your-gps-on-target-34750">GPS</a> and other electronic systems.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/predicting-daily-space-weather-will-help-keep-your-gps-on-target-34750">Predicting daily space weather will help keep your GPS on target</a>
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</em>
</p>
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<p>At present, we can’t make accurate predictions of bad space weather beyond about three days ahead. And the flow-on effects of bad space weather on the Earth’s upper atmosphere, including GPS and communication disturbances and changes in satellite drag, are even harder to forecast ahead of time. </p>
<p>As a result, most space weather prediction agencies are restricted to “nowcasting”: observing the current state of space weather and projecting for the next few hours.</p>
<p>It will take a lot more science to understand the connection between the Sun and the Earth, how energy from the Sun dissipates through the Earth system, and how these system changes influence the technology we increasingly rely on for everyday life.</p>
<p>This means more research and more satellites, especially for the equatorial to mid-latitudes relevant to Australians (and indeed most people on Earth). We hope CUAVA-1 is a step towards a constellation of Australian space weather satellites that will play a key role in future space weather forecasting.</p><img src="https://counter.theconversation.com/content/169027/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brett Carter receives funding from the Australian Reseach Council. He and Iver Cairns acknowledge contributions from the ASPiRE team working on space weather prediction and science.</span></em></p><p class="fine-print"><em><span>Iver Cairns receives funding from the Australian Research Council and Investment NSW. He and Brett Carter acknowledge contributions from the ASPiRE team working on space weather prediction and science.
</span></em></p>The CUAVA-1 cubesat will monitor space weather and changes to Earth’s ionosphere that affect satellites and electronics.Brett Carter, Senior lecturer, RMIT UniversityIver Cairns, Professor of Space Physics, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1598952021-05-05T15:52:51Z2021-05-05T15:52:51ZSpace weather is difficult to predict — with only an hour to prevent disasters on Earth<figure><img src="https://images.theconversation.com/files/397967/original/file-20210429-19-3t3kvx.jpg?ixlib=rb-1.1.0&rect=7%2C39%2C5250%2C6535&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The interaction of solar winds and the Earth’s atmosphere produces the northern lights that dance across the night sky. </span> <span class="attribution"><span class="source">(Benjamin Suter/Unsplash)</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Recent developments at the forefront of astronomy allow us to observe that <a href="https://www.cnn.com/2021/04/13/world/raindrops-other-planets-scn/index.html">planets orbiting other stars have weather</a>. Indeed, we have known that other planets in our own solar system have weather, in many cases more extreme than our own. </p>
<p>Our lives are affected by short-term atmospheric variations of weather on Earth, and we fear that longer-term climate change will also have a large impact. The recently coined term “space weather” refers to effects that arise in space but affect Earth and regions around it. More subtle than meteorological weather, space weather usually acts on technological systems, and has potential impacts that range from communication disruption to power grid failures.</p>
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Read more:
<a href="https://theconversation.com/solar-weather-has-real-material-effects-on-earth-118453">Solar weather has real, material effects on Earth</a>
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</em>
</p>
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<p>An ability to predict space weather is an essential tool in providing warnings so that mitigation can be attempted, and to hopefully, in extreme cases, forestall a disaster. </p>
<h2>The history of weather forecasting</h2>
<p>We are now used to large-scale meteorological forecasts that are quite accurate for about a two-week timescale. </p>
<p>Scientific weather forecasting originated about a century ago, with the term <a href="https://www.smithsonianmag.com/history/how-world-war-i-changed-weather-good-180963360/">“front” being associated with the First World War</a>. Meteorological prediction is based on a good knowledge of underlying theory, codified into massive computer programs running on the most advanced computers, with huge amounts of input data. </p>
<p>Important aspects of weather, like moisture content, can be measured by satellites that monitor continuously. Other measurements are also be readily taken, for example, by the nearly 2,000 weather balloons launched each day. Exploring the limits in weather forecasting gave rise to chaos theory, sometimes called the “butterfly effect.” The buildup of error brings about the two-week practical limit. </p>
<p>In contrast, the prediction of space weather is only truly reliable about one hour in advance!</p>
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<figcaption><span class="caption">An explainer of the science behind chaos.</span></figcaption>
</figure>
<h2>Solar effects</h2>
<p>Most space weather <a href="https://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html">originates from the sun</a>. Its outermost atmosphere blows into space at supersonic speeds, although at such low density that interplanetary space is more rarified than what is considered a vacuum in our laboratories. Unlike winds on Earth, this solar wind carries along a magnetic field. This is much smaller than Earth’s own field that we can detect with a compass at the surface, and vastly smaller than that near a fridge magnet, but it can interact with Earth, with an important role in space weather. </p>
<p>The very thin solar wind, with a very weak magnetic field, can nevertheless affect Earth in part because it interacts with a large magnetic bubble around Earth, called the magnetosphere, over a very large area, at least a hundred times as big as the surface of our planet. Much like a breeze that can barely move a thread can move a huge sailing ship when caught on the large sails, the effect of solar wind, through its direct pressure (like on a sail) or through its magnetic field interacting with Earth’s, can be enormous. </p>
<p>As the origin point, the sun itself is a seething mass of hot gas and magnetic fields, and their interaction is complex, sometimes even explosive. Magnetic fields are concentrated near sunspots, and <a href="https://earthobservatory.nasa.gov/world-of-change/Solar">produce electromagnetic phenomena like solar flares (the name says it all) and coronal mass ejections</a>. Much as with tornadoes on Earth, we know generally when conditions are favourable for these localized explosions, but precise prediction is difficult. </p>
<p>Even once an event is detected, if a large mass of fast, hot and dense gas is shot in our direction (and such a “cloud” in turn is difficult to detect, coming at us against the glare of the sun), there is a further complicating factor in predicting its danger.</p>
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<figcaption><span class="caption">NASA scientists answer questions about space weather.</span></figcaption>
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<h2>Detecting magnetic fields</h2>
<p>Unlike the detectable, sometimes even visible, water content in the atmosphere that is so important in meteorology, the magnetic field of gas ejected from the sun, including in hot and denser clouds from explosions, is almost impossible to detect from afar. The effect of an interplanetary cloud is greatly enhanced if the direction of its magnetic field is opposite to Earth’s own field where it hits the barrier of Earth’s magnetosphere. In that case, a process known as “reconnection” allows much of the cloud’s energy to be transferred to the region near Earth, and accumulate largely on the night side, despite the cloud hitting on the side facing the sun. </p>
<p>By secondary processes, usually involving further reconnection, this energy produces space weather effects. Earth’s <a href="https://www.space.com/33948-van-allen-radiation-belts.html">radiation belts can be greatly energized</a>, endangering astronauts and even satellites. These processes can also produce bright auroras, whose beauty hides danger since they in turn produce magnetic fields. A generator effect takes place when dancing auroras make magnetic fields vary, but unlike in the generators that produce much of our electricity, the electric fields from auroras are uncontrolled. </p>
<p>The electric fields from auroras are small, and undetectable to human senses. However, over a very large region they can build up to apply a considerable voltage. It’s this effect that poses a hazard to our largest infrastructure, such as electric grids. To predict when this might happen, we would need to measure from afar the size and direction of magnetic field in an incoming space cloud. However, that invisible field is stealthy and hard to detect until it is nearly upon us.</p>
<h2>Satellite monitors</h2>
<p>By the gravitational laws of orbits, a satellite continuously monitoring magnetic fields by direct measurement must sit about a million miles (1.6 million kilometres) from Earth, between us and the sun a hundred times further away. A magnetic cloud causing minor space weather effects usually takes about three days to come from the sun to Earth. A truly dangerous cloud, from a bigger solar explosion, may take as little as a day. Since our monitoring satellites are relatively close to Earth, we only know about the crucial magnetic field direction at most one hour in advance of impact. This is not much time to prepare vulnerable infrastructure, like power and communication networks and satellites, to best survive.</p>
<p>Since the fleets of satellites needed to give better warning are not even on the drawing boards, we must rely on luck in the face of space weather. It may be a small comfort that the coming solar maximum — when the surface of the sun is at its most active during a cycle and is expected to peak in 2025 — <a href="https://www.nasa.gov/press-release/solar-cycle-25-is-here-nasa-noaa-scientists-explain-what-that-means">is predicted to be mild</a>. </p>
<p>It may be Mark Twain who said “it is hard to make predictions, especially about the future,” but it is certainly true in the case of space weather.</p><img src="https://counter.theconversation.com/content/159895/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin Gerard Connors receives funding from NSERC, the Canada Foundation for Innovation, Alberta Innovation, and the Canadian Space Agency. </span></em></p>It has only been in the past century that weather prediction on Earth has advanced enough to work two weeks in advance. Predicting space weather, however, is only reliable an hour in advance.Martin Connors, Professor of Space Science and Physics, Athabasca UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1576302021-03-29T11:12:26Z2021-03-29T11:12:26ZWhy we need to get better at predicting space weather<figure><img src="https://images.theconversation.com/files/391681/original/file-20210325-19-cp881k.jpg?ixlib=rb-1.1.0&rect=155%2C116%2C6334%2C3327&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A solar flare.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/sun-solar-flare-particles-coronal-mass-752393257">Shutterstock/Color4260</a></span></figcaption></figure><p>The Sun is the most important source of energy for sustaining life on Earth, but it gives us a lot more than just light and heat. It also gives us solar storms. </p>
<p>Disturbances on the Sun, such as coronal mass ejections produced by solar flares that emanate from active sunspot regions, can cause solar storms. Solar flares and coronal mass ejections emit vast quantities of radiation and charged particles into space. </p>
<p>These events can damage the Earth’s <a href="https://theconversation.com/solar-storms-could-lead-to-a-global-techno-meltdown-16678">communication and power infrastructures</a>, resulting in power outages and reduced system functionality. Satellites, space stations and astronauts, aviation, GPS, power grids and more can be affected.</p>
<p>As our civilisation becomes more advanced, we become more vulnerable to the effects of solar storms. Now, as the Sun’s activity <a href="https://www.esa.int/Safety_Security/Solar_cycle_25_the_Sun_wakes_up">is on the increase</a>, we need to get better at predicting solar weather.</p>
<p>Many people still remember the collapse of Canada’s Quebec electrical grid on <a href="https://www.nasa.gov/topics/earth/features/sun_darkness.html">13 March 1989</a>, which lasted for nine hours and affected six million people. It caused hundreds of millions of dollars in damages and lost revenues. This blackout was caused by solar storms. </p>
<p><a href="https://www.swsc-journal.org/articles/swsc/pdf/2013/01/swsc130015.pdf">The Carrington Event</a>, named for the amateur astronomer who recorded it, was another powerful solar storm which happened in September 1859. Cutting edge technology in 1859 was limited to electrical telegraphs, and most of those failed all over Europe and North America, in some cases giving their operators electric shocks. </p>
<p>These days, we’re much more reliant on technology, which is in turn increasingly vulnerable to the effects of space and its unique natural disasters.</p>
<h2>Space radiation</h2>
<p>Space is vast, cold, dark and awash with radiation. Radiation in space comes mainly from galactic cosmic radiation – high energy particles thrown out from other galaxies – and solar particle events – high energy particles from our own Sun.</p>
<p>In space radiation, atoms are accelerated in interstellar space to speeds close to the speed of light. Eventually, the electrons are stripped out and only the positively charged nucleus remains.</p>
<p>Humans have been observing and counting sunspots for more than 400 years, making this the <a href="https://www.nature.com/news/long-term-research-slow-science-1.12623#:%7E:text=The%20world's%20longest%2Drunning%20experiments,a%20marathon%2C%20not%20a%20sprint.&text=Although%20science%20is%20a%20long,length%20of%20a%20funding%20cycle.">longest running experiment</a> in the world. The sun has an 11-year sunspot cycle, and at the moment, we are in the middle of that cycle. Now it’s approaching “solar maximum”, where the greatest solar activity occurs. The next solar maximum is expected to begin in 2025.</p>
<figure class="align-center ">
<img alt="The northern lights over a lake." src="https://images.theconversation.com/files/391688/original/file-20210325-19-1i3lp77.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391688/original/file-20210325-19-1i3lp77.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391688/original/file-20210325-19-1i3lp77.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391688/original/file-20210325-19-1i3lp77.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391688/original/file-20210325-19-1i3lp77.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391688/original/file-20210325-19-1i3lp77.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391688/original/file-20210325-19-1i3lp77.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The northern lights are caused by solar flares.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/icelandic-spiral-northern-lights-autumn-time-528933889">Shutterstock/Mike-Hubert.com</a></span>
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</figure>
<p>People are familiar with the northern lights, which is one visible effect of solar radiation. Earth’s magnetic field, which protects us from most of the dangers of space radiation, directs the charged particles to the poles, where they enter our atmosphere and cause beautiful light displays.</p>
<p>But the radiation can also impact technology and people. During strong solar radiation storms, energetic protons can damage electronic circuits inside satellites and the biological DNA of astronauts. Passengers and crew flying over the north pole would be exposed to increased radiation. </p>
<p>These radiation storms can create errors that make navigation operations extremely difficult. Energetic protons can also ionise the atoms and molecules in the atmosphere, creating a layer of free electrons. This layer can absorb high-frequency radio waves, causing a blackout of high-frequency communications, also known as shortwave radio.</p>
<p>With our increasing reliance on technology, predicting the weather in space is crucial. However, accurately predicting space weather has long been a challenging problem for experts.</p>
<h2>Predicting space weather</h2>
<p>Understanding the complexity of sunspots will help us predict whether significant solar flares may happen. My colleagues and I developed a real-time automated computer system which uses image processing and artificial intelligence technologies to monitor and analyse solar satellite data. This helps predict the likelihood of solar flares in the coming 24 hours. </p>
<p>We pioneered new techniques for automatic processing, detection and feature extraction of solar features – like active regions and sunspots – captured by Nasa’s solar dynamics observatory satellite. We also introduced the first automated and real-time system <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008SW000401">to classify sunspots</a>. Before this, the classification of sunspots was a manual process painstakingly carried out by experts. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/four-graphs-that-suggest-we-cant-blame-climate-change-on-solar-activity-130154">Four graphs that suggest we can't blame climate change on solar activity</a>
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<p>Space missions and astronauts are much more likely to be affected by radiation, because they aren’t protected by Earth’s magnetic field. The effects on humans could include radiation sickness, increased risk for cancer, degenerative diseases and central nervous system effects. </p>
<p>Despite these risks, human and robotic activities are increasing in space and Nasa is working to land humans on Mars by the 2030s. There are two rovers – <a href="https://theconversation.com/curiosity-catches-a-whiff-of-methane-on-mars-and-a-possibility-of-past-life-35595">Curiosity</a> and <a href="https://theconversation.com/mars-perseverance-rover-set-for-nail-biting-landing-heres-the-rocket-science-154886">Perseverance</a> – and <a href="https://theconversation.com/mars-insight-why-well-be-listening-to-the-landing-of-the-perseverance-rover-153672">one lander</a> currently operational on Mars, with <a href="https://theconversation.com/how-the-exomars-mission-could-sniff-out-life-on-mars-and-what-to-do-next-56182">another rover planned</a> for launch in 2022. </p>
<p>Our space weather prediction system is <a href="http://spaceweather.inf.brad.ac.uk/">publicly available</a>, and is now used as one of the decision-making tools for Nasa’s robotic missions and to manage radiation effects on Nasa’s Chandra X-ray observatory orbit.</p>
<p>As we continue venturing further into space, we’ll need to strengthen our current space weather prediction capabilities to build a greater picture of solar activity and mitigate its effects around the solar system. </p>
<p>This task is incredibly challenging, as most solar observations are taken for Earth’s field of view. Better modelling and investigation of the evolution of solar features is necessary to accommodate for the drastically different celestial orbits around the Sun.</p><img src="https://counter.theconversation.com/content/157630/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rami Qahwaji received funding from The Engineering and Physical Sciences Research Council (EPSRC), European Commission, and the European Space Agency.</span></em></p>Satellites, space stations and astronauts, aviation, GPS, power grids and more can be affected.Rami Qahwaji, Professor of Visual Computing, University of BradfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1509792020-12-09T19:12:33Z2020-12-09T19:12:33ZBad space weather may make life impossible near Proxima Centauri<figure><img src="https://images.theconversation.com/files/372461/original/file-20201202-21-17lgvmk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's depiction of a flare-coronal mass ejection event on Proxima Centauri.</span> <span class="attribution"><span class="source">Mark Myers, ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>If you look up in the southern sky you can see the “pointer” stars, pointing towards the Southern Cross. One of these pointers is Alpha Centauri, which is actually a pair of Sun-like stars that are too close together to tell apart by eye. </p>
<p>There is a third member of the Alpha Centauri system as well: Proxima Centauri (Proxima Cen for short), which circles the central two stars in a wide orbit. This is the Sun’s nearest neighbour, at a distance of just 4.2 light years.</p>
<p>It is possible one of Proxima Cen’s planets is suitable for life. However, <a href="https://doi.org/10.3847/1538-4357/abca90">we recently detected</a> the signature of fierce space weather from Proxima Cen, which implies an orbiting planet could be blasted with hazardous particles and magnetic fields.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/372375/original/file-20201201-19-1n6c2qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/372375/original/file-20201201-19-1n6c2qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/372375/original/file-20201201-19-1n6c2qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/372375/original/file-20201201-19-1n6c2qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/372375/original/file-20201201-19-1n6c2qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/372375/original/file-20201201-19-1n6c2qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/372375/original/file-20201201-19-1n6c2qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/372375/original/file-20201201-19-1n6c2qz.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">Five of the 36 ASKAP antennas poised below a vista of the Milky Way. The Southern Cross and the Pointers are visible just above the central antenna in the image.</span>
<span class="attribution"><span class="source">CSIRO/Alex Cherney</span></span>
</figcaption>
</figure>
<h2>Our neighbour is not like the Sun</h2>
<p>Our Sun is a relatively unremarkable yellow dwarf star, hosting the only known life-bearing planet in the Universe: our Earth.</p>
<p>Proxima Cen is very different. It is a red dwarf star, with a diameter only 15% of the Sun’s, and a surface temperature of 3,000K (degrees Kelvin), much cooler than the Sun’s 6,000K. </p>
<p>Because Proxima Cen is relatively cool, the “Goldilocks zone” of orbits around it – where the temperature is just right for liquid water – is around one-twentieth the Earth’s distance from the Sun. We are interested in planets in a star’s Goldilocks zone because liquid water is necessary for life as we know it. </p>
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<strong>
Read more:
<a href="https://theconversation.com/say-hello-to-the-earths-nearest-exoplanet-neighbour-proxima-centauri-b-64351">Say hello to the Earth's nearest exoplanet neighbour: Proxima Centauri b</a>
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<p>We know Proxima Cen has at least two planets: Proxima Cen b, a rocky “super-Earth” located in the middle of Proxima Cen’s Goldilocks zone, and Proxima Cen c, a “sub-Neptune” located further out.</p>
<p>For years, astronomers have suspected planets like Proxima Cen b may be a dangerous home for life because they are so close to their host stars. Many red dwarf stars produce frequent, powerful flares – intense bursts of radiation travelling out into space. If planets like Proxima Cen b don’t have protective features such as a thick atmosphere or a strong magnetic field, they would be exposed to perilous levels of radiation.</p>
<h2>But what’s the weather like around these stars?</h2>
<p>The “space weather” of red dwarfs is another important factor in determining how hospitable they are to life. While flares involve intense bursts of light, space weather events mean the magnetic field and charged particles from the star can interact with planets directly.</p>
<p>The most energetic space weather events are known as <a href="https://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html#q4">coronal mass ejections (or CMEs)</a>. These massive eruptions escape the atmosphere of a star and travel through space at millions of kilometres per hour.</p>
<p>If the space weather conditions are extreme enough, the planetary atmosphere can be blown away and its magnetic field can be pushed backwards, leaving the surface exposed to deadly flare radiation.</p>
<p>CMEs have been detected around the Sun since the 1970s, but detecting space weather events around distant stars is much harder. </p>
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<img src="https://cdn.theconversation.com/static_files/files/1349/2012cme.gif?1606883521" width="100%">
<figcaption>
<span class="caption">A sequence of powerful coronal mass ejections from the Sun, observed by the ESA/NASA Solar and Heliospheric Observatory (SOHO). The Sun is located behind the central masked circle.</span>
<span class="attribution"><span class="source">ESA/NASA/SOHO</span></span>
</figcaption>
</figure>
<p><a href="https://cdn.theconversation.com/static_files/files/1349/2012cme.gif?1606883521"></a></p>
<h2>For updates on the weather, tune into the radio</h2>
<p>CMEs on the Sun produce characteristic bursts of radio noise, such as “type II” and “type IV” bursts. By detecting similar signatures on other stars, we can indirectly identify stellar CMEs.</p>
<p>In early 2019, we pointed our telescopes at Proxima Cen for 11 nights. We used CSIRO’s new radio telescope, the <a href="https://www.csiro.au/en/Research/Facilities/ATNF/ASKAP">Australian Square Kilometre Array Pathfinder (ASKAP)</a>, as well as the <a href="https://www.zt.ems.uwa.edu.au">Zadko Telescope</a>, the <a href="https://rsaa.anu.edu.au/observatories/telescopes/anu-23m-telescope">ANU 2.3m Telescope</a>, and NASA’s <a href="https://www.nasa.gov/tess-transiting-exoplanet-survey-satellite/">Transiting Exoplanet Survey Satellite (TESS)</a>.</p>
<p>Our goal was to detect the signature of a CME. </p>
<p>On the night of May 2, 2019, we observed a massive optical flare with an estimated total energy output of 16 septillion joules. (That’s nearly 17 million years’ worth of Australia’s current electricity output.) On the Sun, flares this big happen only once every decade or two. But on Proxima Cen, they happen every few weeks.</p>
<p>Using ASKAP, we observed a spectacular sequence of intense radio bursts. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/372396/original/file-20201201-19-19l04dt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/372396/original/file-20201201-19-19l04dt.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=322&fit=crop&dpr=1 600w, https://images.theconversation.com/files/372396/original/file-20201201-19-19l04dt.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=322&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/372396/original/file-20201201-19-19l04dt.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=322&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/372396/original/file-20201201-19-19l04dt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=404&fit=crop&dpr=1 754w, https://images.theconversation.com/files/372396/original/file-20201201-19-19l04dt.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=404&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/372396/original/file-20201201-19-19l04dt.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=404&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Radio and optical data from Proxima Cen on the night of May 2 2019. The top panel shows the ASKAP ‘dynamic spectrum’, showing how the intensity varies with radio frequency and time. The bottom panel shows data from optical telescopes, revealing a powerful outburst of radiation. When paired together, the occurrence of powerful radio bursts associated with flaring activity becomes clear.</span>
<span class="attribution"><span class="source">Andrew Zic/University of Sydney/CSIRO</span></span>
</figcaption>
</figure>
<p>With the amazing detail revealed with ASKAP, we could see we had detected the best example of a solar-like type IV radio burst from another star to date.</p>
<p>This blast of radio waves implies the space weather environment around Proxima Cen is quite violent.</p>
<h2>‘One swallow does not make a summer’</h2>
<p>In 1859, British astronomers Richard Carrington and Richard Hodgson made the first observations of a solar flare, which was followed by a massive space weather storm named the “<a href="https://en.wikipedia.org/wiki/Carrington_Event">Carrington event</a>”. We now know the storm was caused by a massive coronal mass ejection hitting Earth.</p>
<p>Carrington noted the coincidence between these extraordinary events, but was cautious to draw any connection between them, famously stating “one swallow does not make a summer”. We now find ourselves in a similar situation to Carrington. </p>
<p>We have observed a radio burst signature implying a CME erupting from Proxima Cen. But to confirm the relationship of these stellar radio bursts with CMEs, we need to harness information from other wavelengths. Once we can do this, we should soon know exactly how hazardous it is to live next to a star like Proxima Centauri.</p>
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<strong>
Read more:
<a href="https://theconversation.com/is-alpha-centauri-the-right-place-to-search-for-life-elsewhere-57716">Is Alpha Centauri the right place to search for life elsewhere?</a>
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<img src="https://counter.theconversation.com/content/150979/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Zic received support from an Australian Government Research Training Program Scholarship, and as a Graduate Student with CSIRO Astronomy and Space Science. Andrew is now a Research Plus Postdoctoral Fellow with CSIRO, hosted by Macquarie University.</span></em></p><p class="fine-print"><em><span>Tara Murphy receives funding from the Australian Research Council. She is an Associate Investigator of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav).
</span></em></p>We observed a powerful flare and a huge burst of radio waves from our nearest stellar neighbour, Proxima Centauri, indicating violent space weather around the star.Andrew Zic, Postdoctoral Research Fellow at Macquarie University, CSIROTara Murphy, Professor and ARC Future Fellow, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1374572020-04-30T18:03:21Z2020-04-30T18:03:21ZThe Sun: study shows it’s less active than sibling stars – here’s what that could mean<figure><img src="https://images.theconversation.com/files/331567/original/file-20200429-51457-ll2phm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The sun emitting a sudden flash of light—a solar flare.</span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>All stars emit varying amounts of light over time – and the Sun is no exception. Such changes in starlight can help us understand how habitable any planets around other stars are – a very active star may bombard its planets with harmful radiation. Now a new study, <a href="https://science.sciencemag.org/cgi/doi/10.1126/science.aay3821">published in Science</a>, shows that the Sun is significantly less active than other, similar stars. </p>
<p>In many stars, the observed variation in brightness is driven by their internal magnetic field. When parts of the magnetic field breaks out through a star’s surface, it can cause dark regions known as <a href="https://aasnova.org/2018/12/12/what-are-starspots-like-on-sun-like-stars/">starspots</a> or brighter regions (known as <a href="https://www.isf.astro.su.se/highlights/faculae-explained/">faculae</a>) in the star’s atmosphere. As a star rotates on its axis, so the bright and dark regions pass across the face of the star from our viewpoint, causing a periodic change in brightness of the star as a result.</p>
<p>Some of the most extreme examples of variable stars are <a href="https://britastro.org/vss/EBHandbook11.pdf">eclipsing binary stars</a> and <a href="https://www.atnf.csiro.au/outreach/education/senior/astrophysics/variable_pulsating.html">pulsating stars</a>. In the former, the light variation is due to an external effect: a pair of stars orbit around their common centre of mass, repeatedly blocking some of their partner’s light from our point of view. If the orbit is viewed edge-on, the brightness of the star will appear to decrease significantly at regular intervals.</p>
<p>In a pulsating star, the light variation has an intrinsic cause: the star literally pulses in and out, becoming larger then smaller, brighter then fainter, with a regularly repeating pattern of changing brightness. Pulsating stars can change in brightness by a factor of ten or more with each cycle. Both of these classes of stars are favourite targets for astronomers, as their light variation may be used to probe the dynamics or structure of a stellar system.</p>
<h2>Calm before the storm?</h2>
<p>The stellar brightness variations due to bright and dark spots rotating across our line of sight are generally of much lower amplitude though. The Sun’s brightness only varies by a fraction of a percent as it rotates once every <a href="https://www.livescience.com/32894-does-the-sun-rotate.html">24 days</a>. Even such small changes can affect the Earth’s climate on timescales of decades or its atmospheric chemistry on timescales as short as months or days. </p>
<p>We have <a href="https://www.space.com/42702-400-years-solar-observations.html">records of sunspots</a> dating back to 1610, and they show that the Sun regularly goes through a cycle every 11 years during which the number of sunspots alternately reach a maximum and then virtually disappear entirely. When sunspots are at their most prevalent, the Sun is particularly active – outbursts of light known as <a href="https://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html">solar flares and coronal mass ejections</a> are more common. These can have significant impact on our lives here on Earth. As well as causing the <a href="https://www.nasa.gov/content/about-auroras">northern lights</a>, they can also disrupt satellites and damage power lines. </p>
<p>In the new study, researchers compared a detailed 140-year record of the Sun’s brightness with the light curves of a set of solar siblings observed by the <a href="https://www.nasa.gov/mission_pages/kepler/overview/index.html">Kepler satellite</a> over the course of four years. They looked at stars whose temperature, mass, radius and age were all similar to the Sun, and selected 349 stars for which the rotation period could be measured as between 20 and 30 days. </p>
<p>The astronomers measured a range of variability from 0 (no change in brightness) to 0.75%, with an average around 0.36%. By taking random four-year segments of the Sun’s light curve, they found the typical variability of the Sun’s brightness was only 0.07% – and even at its greatest was no more than 0.20%. They therefore concluded that most stars of the same type as the Sun are more active than the Sun.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/331566/original/file-20200429-51461-f4gb0f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/331566/original/file-20200429-51461-f4gb0f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331566/original/file-20200429-51461-f4gb0f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331566/original/file-20200429-51461-f4gb0f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331566/original/file-20200429-51461-f4gb0f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331566/original/file-20200429-51461-f4gb0f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331566/original/file-20200429-51461-f4gb0f.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">
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<span class="caption">Brightness variations of the Sun in comparison with the star KIC 7849521.</span>
<span class="attribution"><span class="source">MPS / hormesdesign.de</span></span>
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</figure>
<p>So does this mean that the Sun is genuinely different to other stars in the same class? Astronomers know that, as stars age, their <a href="https://www.astrobio.net/cosmic-evolution/gyrochronology/">rotation slows</a> and they become less magnetically active. At some point they may transition to a new phase of very low activity - but we don’t know exactly when that transition occurs. Perhaps the Sun is approaching such a stage in its life. Alternatively, could it simply be that, in the 140 years of solar data used, we have only sampled a relatively quiet period of the Sun’s activity – might it have been more active at other times?</p>
<p>This possibility is more worrying. It might suggest that the Sun could undergo periods when its variability is much higher, with a corresponding increase in magnetic activity and stronger outflows that could disrupt life here on Earth. </p>
<p>Perhaps comfortingly, measurements of certain isotopes – variants of chemical elements with lighter or heavier nuclei – on Earth can be used to <a href="https://www.aanda.org/articles/aa/pdf/2018/12/aa32956-18.pdf">track solar activity</a> over the last 9000 years. They reveal that the variation of the Sun’s brightness has not changed significantly on this timescale either.</p>
<p>Understanding stellar variability is vital for assessing the habitability of exoplanets. In extreme cases, stellar flares may strip the atmosphere from an otherwise habitable exoplanet, rendering it unsuitable for life. The recently discovered planet orbiting the nearest star, <a href="https://theconversation.com/possibly-habitable-planet-found-around-our-nearest-neighbour-star-64321">Proxima b</a>, for example, is in its star’s habitable zone, but Proxima Centauri itself is a very active star and the planet is most likely bathed in harmful radiation from stellar flares.</p>
<p>This new study may indicate that only very inactive stars such as the Sun are likely to host habitable exoplanets. Perhaps we should be grateful that the Sun is among the more sedate of its siblings.</p><img src="https://counter.theconversation.com/content/137457/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Norton 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>Has the Sun entered a stage of old age?Andrew Norton, Professor of Astrophysics Education, The Open UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1184532019-07-10T21:23:21Z2019-07-10T21:23:21ZSolar weather has real, material effects on Earth<figure><img src="https://images.theconversation.com/files/283405/original/file-20190709-44487-194iyqg.jpg?ixlib=rb-1.1.0&rect=9%2C0%2C6480%2C3648&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Solar flares and other phenomena can have a surprising effect on our Earthly activities.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>On Sep. 1, 1859, solar astronomer Richard Carrington <a href="https://science.nasa.gov/science-news/science-at-nasa/2008/06may_carringtonflare">witnessed sunspots that suddenly and briefly flashed brightly before they disappeared</a>. Just before dawn the next day, auroras erupted over most of the Earth, reaching as far south as the Caribbean and Hawaii while southern lights were seen as far north as Chile. The event produced not only a visible light show in areas where they do not typically appear, <a href="https://news.nationalgeographic.com/news/2011/03/110302-solar-flares-sun-storms-earth-danger-carrington-event-science/">but it also sent telegraph systems around the world haywire</a>. </p>
<p>Given the state of technology during Carrington’s time, the impact of a geomagnetic storm was limited to disruptions of telegraph service. If something similar happened today, the world’s technological infrastructure could grind to a halt. Extreme space weather events such as geomagnetic storms are <a href="http://lasp.colorado.edu/home/wp-content/uploads/2011/07/lowres-Severe-Space-Weather-FINAL.pdf">more disruptive now</a> than in the past. This is because of our greater dependence on technical systems that can be affected by electric currents and energetic particles high in the Earth’s atmosphere.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/nNng0KrNUuI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An active region on the sun — an area of intense and complex magnetic fields — has rotated into view on the sun in this video captured by NASA’s Solar Dynamics Observatory between July 5-11, 2017. The dark core of this sunspot is larger than Earth.</span></figcaption>
</figure>
<h2>The space weather threat</h2>
<p>We might think of space as a silent, empty void and the sun as only a distant source of light and heat. This is not necessarily true. <a href="https://www.huffpost.com/entry/the-unpredictability-of-s_b_9721612">The sun and the Earth are connected in more complex, intimate and sometimes dangerous ways</a>. </p>
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Read more:
<a href="https://theconversation.com/the-scorching-winds-on-the-surface-of-the-sun-and-how-were-forecasting-them-44098">The scorching winds on the surface of the sun – and how we're forecasting them</a>
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<p>Sunspots are <a href="http://swe.ssa.esa.int/what-is-space-weather">temporary phenomena on the sun’s photosphere</a> that appear darker than the surrounding areas. Sunspots can change continuously and may last for only a few hours to days; or even months for the more intense groups. <a href="https://www.swpc.noaa.gov/news/sunspots-and-solar-cycles">The total number of sunspots has long been known to vary with an approximately 11-year repetition known as the solar cycle.</a> The peak of sunspot activity is known as solar maximum and the lull is known as solar minimum. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/283143/original/file-20190708-51258-3lyq8n.jpg?ixlib=rb-1.1.0&rect=9%2C10%2C987%2C775&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/283143/original/file-20190708-51258-3lyq8n.jpg?ixlib=rb-1.1.0&rect=9%2C10%2C987%2C775&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/283143/original/file-20190708-51258-3lyq8n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=470&fit=crop&dpr=1 600w, https://images.theconversation.com/files/283143/original/file-20190708-51258-3lyq8n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=470&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/283143/original/file-20190708-51258-3lyq8n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=470&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/283143/original/file-20190708-51258-3lyq8n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=591&fit=crop&dpr=1 754w, https://images.theconversation.com/files/283143/original/file-20190708-51258-3lyq8n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=591&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/283143/original/file-20190708-51258-3lyq8n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=591&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Vivid orange streamers of super-hot, electrically charged gas (plasma) arc from the surface of the sun, revealing the structure of the solar magnetic field rising vertically from a sunspot.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/mission_pages/hinode/news/five-yearsa.html">Hinode, JAXA/NASA</a></span>
</figcaption>
</figure>
<p>Indicating intense magnetic activity, sunspots accompany secondary phenomena such as bursts of electromagnetic radiation (flares) and coronal mass ejections (CME) — which are sudden eruptions of material — accompanied by solar energetic particles (SEPs). A solar flare is a sudden release of energy from the sun, while a CME shoots hot plasma from the sun into space. </p>
<p>The precise mechanisms that trigger flares and CMEs are still being debated, but the bigger the group of sunspots, <a href="https://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html#q8">the more intense solar activity tends to be</a>. The sun continually ejects high-energy electrons, protons and other nuclei that bombard the Earth. <a href="https://www.space.com/11506-space-weather-sunspots-solar-flares-coronal-mass-ejections.html">Solar flares and CMEs send enormous amounts of energy</a> and charged particles hurtling into collision with the Earth’s upper atmosphere, where they can cause geomagnetic storms.</p>
<p>Charged particles during geomagnetic storms cause disturbances in the Earth’s magnetic field, generating effects on electrical systems. <a href="https://doi.org/10.1111/risa.12765">Geomagnetic storms produce numerous effects</a> such as voltage disruptions leading to power outages; changes in soil voltage that enhance corrosion in oil pipelines; disruption in satellite, radio and cellular communications networks; exposure to elevated levels of radiation; and reductions in flights with polar routes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/283404/original/file-20190709-44487-kk7r6v.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/283404/original/file-20190709-44487-kk7r6v.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/283404/original/file-20190709-44487-kk7r6v.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/283404/original/file-20190709-44487-kk7r6v.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/283404/original/file-20190709-44487-kk7r6v.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/283404/original/file-20190709-44487-kk7r6v.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/283404/original/file-20190709-44487-kk7r6v.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/283404/original/file-20190709-44487-kk7r6v.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">A solar flare surges off the lower left hand of the sun on Oct. 19, 2014. The image was captured in extreme ultraviolet wavelength of 131 Angstroms – a wavelength that can see the intense heat of a flare and that is typically represented in teal.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/content/goddard/new-sunspot-releases-x11-class-solar-flare">NASA/SDO</a></span>
</figcaption>
</figure>
<p>For the most part, the Earth’s magnetic field protects humans from the barrage of radiation which comes from the sun. However, the Earth’s magnetic field is weaker at either pole and therefore some particles of enter the Earth’s atmosphere through geomagnetic storms. </p>
<h2>Solar weather effects</h2>
<p>The adverse economic impacts of solar activity on the North American power grid have been well-documented. For instance, <a href="https://doi.org/10.1051/swsc/2013041">four per cent of the power disturbances</a> between 1992 and 2010 reported to the U.S. Department of Energy are attributable to strong geomagnetic activity.</p>
<p>I have been working on the <a href="https://ideas.repec.org/p/wis/wpaper/1707.html">economic effects of climate change</a> for some time now and thought: “How about the sun?” </p>
<p>Interestingly, while the study of space weather is a rapidly growing field, academic work to assess its overall social and economic impacts appears to be in its infancy. </p>
<p>I am currently working with one of my former graduate students, Zichun Zhao, on the economic impacts of space weather. Our proxy measure of solar activity is the number of sunspots produced by the sun at a given time and, luckily, this data is <a href="http://www.sidc.be/silso/datafiles">publicly available</a>. </p>
<p>In our empirical analysis, we found that the <a href="https://data.oecd.org/gdp/gross-domestic-product-gdp.htm">Gross Domestic Products (GDP) of the 34-member countries of the Organization for Economic Co-operation and Development</a> decreases as solar activity increases. On average, GDP decreases by at least 0.06 per cent for every increase of one per cent in solar activity. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/how-space-weather-poses-a-risk-to-the-finance-industry-64621">How space weather poses a risk to the finance industry</a>
</strong>
</em>
</p>
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<p>We find that the negative economic effects of geomagnetic storms are more significant in northern latitudes. However, the effects of geomagnetic storms <a href="https://www.nasa.gov/topics/earth/features/sun_darkness.html">are not restricted to high latitudes</a> and have been documented in the <a href="http://nora.nerc.ac.uk/id/eprint/500436/">United Kingdom</a>, <a href="https://yle.fi/uutiset/osasto/news/solar_storm-triggered_northern_lights_likely_across_finland__if_clouds_clear/9822507">Finland</a>, <a href="https://phys.org/news/2015-11-sweden-solar-flare-flight.html">Sweden</a>, <a href="https://www.mapfre.com/fundacion/html/revistas/seguridad/n133/en/article2.html">Spain</a>, the <a href="https://www.nap.edu/catalog/12507/severe-space-weather-events-understanding-societal-and-economic-impacts-a">U.S., Canada</a>, <a href="https://www.fin24.com/Tech/News/massive-solar-storm-could-affect-dstv-and-internet-20170908">South Africa</a>, <a href="https://doi.org/10.1051/swsc/2019013">Japan</a>, <a href="http://dx.doi.org/10.1002/cjg2.1261">China</a> and <a href="https://ui.adsabs.harvard.edu/abs/2008cosp%2E%2E%2E37.1491K/abstract">Brazil</a>.</p>
<p>Our empirical results indicate that damages caused by geomagnetic storms are much greater in the information and communications sectors.</p><img src="https://counter.theconversation.com/content/118453/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Batu 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 sun’s phenomena, like flares, can cause solar particles to enter the Earth’s atmosphere, with material effects.Michael Batu, Assistant Professor, Department of Economics, University of WindsorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1193492019-07-02T11:27:03Z2019-07-02T11:27:03ZTotal solar eclipses reveal the dark and stormy side of the sun we never see<figure><img src="https://images.theconversation.com/files/282091/original/file-20190701-105187-ref4z6.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4096%2C4083&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The low solar corona as viewed in extreme ultraviolet light. Bright regions are where the most energetic solar storms are born. An eruption in action can be seen in the bottom-left.</span> <span class="attribution"><span class="source">NASA’s Solar Dynamic Observatory (SDO) satellite.</span>, <span class="license">Author provided</span></span></figcaption></figure><p>In astronomy, we have a common saying: “good luck, and clear skies”. For an eclipse chaser like me, this is especially important. We have two minutes and no second chance – one small cloud can spoil everything.</p>
<p>Thousands of tourists turn up to see them, along with a few dozen scientists, for which the eclipse is a unique opportunity to observe the extended atmosphere of the sun – known as the solar corona. Just like Earth, the sun has an atmosphere and magnetic field which extends out to large distances into space. The solar corona is an intense plasma of separated protons and electrons that’s a million degrees Celsius or hotter.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/282186/original/file-20190702-28330-h88hkq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/282186/original/file-20190702-28330-h88hkq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/282186/original/file-20190702-28330-h88hkq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=374&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282186/original/file-20190702-28330-h88hkq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=374&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282186/original/file-20190702-28330-h88hkq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=374&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282186/original/file-20190702-28330-h88hkq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=470&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282186/original/file-20190702-28330-h88hkq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=470&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282186/original/file-20190702-28330-h88hkq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=470&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sunspots on September 1, 1859, as sketched by Richard Carrington. A and B mark the initial positions of an intensely bright event, which moved over the course of five minutes to C and D before disappearing.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Solar_storm_of_1859#/media/File:Carrington_Richard_sunspots_1859.jpg">Richard Carrington/Wikipedia</a></span>
</figcaption>
</figure>
<p>In this alien environment of hot, magnetised plasma, physics behaves in ways that are poorly understood. Our safety on Earth may depend on understanding it better though – explosive events in the corona can have dramatic and potentially hazardous effects on Earth. </p>
<p>There’s a constant flow of material from this layer of the sun into interplanetary space that’s called the solar wind. In 1859, scientists first discovered it when a solar flare was followed by intense aurora on Earth – also known as Northern or Southern Lights. They were apparently bright enough for people to read newspapers by their light at night. This was known as “the Carrington Event” – electrical currents generated by the flare caused damage to telegraph systems.</p>
<p>As society has become increasingly dependent on technology, understanding space weather and being able to predict it is more important than ever. Eruptions from the sun can damage and disrupt spacecraft, power systems, airlines, communications and GPS systems. A major eruption under the right conditions, like the event in 1859, could cause <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/risa.12765">huge damage to the global economy</a>, on the order of hundreds of billions of dollars.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/282188/original/file-20190702-28290-yn5e6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/282188/original/file-20190702-28290-yn5e6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282188/original/file-20190702-28290-yn5e6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282188/original/file-20190702-28290-yn5e6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282188/original/file-20190702-28290-yn5e6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282188/original/file-20190702-28290-yn5e6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282188/original/file-20190702-28290-yn5e6j.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">Aurora Borealis over Tromso, Norway. The sun’s solar wind collides with Earth’s atmosphere, creating the lights known as the Northern or Southern Lights.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/aurora-borealis-tromso-norway-front-norwegian-497083891?src=A7ZRigJQBbdktHaQ8pt2Ng-1-10&studio=1">Mu Yee Ting/Shutterstock</a></span>
</figcaption>
</figure>
<h2>The dark side of the sun</h2>
<p>Outside of an eclipse, the solar corona is made invisible by the extremely bright light coming directly from the sun’s visible surface – the photosphere. The photosphere is over a million times brighter than even the brightest regions of the corona, so observing the corona is a bit like studying the behaviour of a glowworm hovering next to a lighthouse. Scientists will have spent years, and plenty of funding, preparing for this two-minute phenomenon.</p>
<p>A total eclipse occurs when the moon passes in front of the sun, blocking the sun’s bright disk and casting a deep shadow onto Earth. Over the course of a few hours, the shadow zooms across Earth’s surface faster than Concorde. The “path of totality” – the name for the course the shadow follows – is so large it spans oceans and continents.</p>
<p>Luckily for us, the corona is revealed in all its glory during a total solar eclipse. And luck really is the right word in this context. Imagine the odds of an inhabited planet with intelligent life having a moon that is of the right size and distance to appear the same size in the sky so that it can eclipse the sun. As the moon covers the bright disk of the sun, the surrounding atmosphere appears as a faint ring, with extended rays that point outwards from the sun like a crown – hence the name corona.</p>
<p>To observe the sun safely and study the corona during an eclipse, you need the special filters in a spectrometer. The spectrometer accepts light from the solar corona along a long, narrow entrance slit and during the eclipse, this slit scans to observe the whole corona. The light is split into three channels according to wavelength, and then dispersed onto detectors which record how dense and hot the plasma is – information scientists can’t obtain otherwise.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/282203/original/file-20190702-126355-9o5qa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/282203/original/file-20190702-126355-9o5qa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282203/original/file-20190702-126355-9o5qa6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282203/original/file-20190702-126355-9o5qa6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282203/original/file-20190702-126355-9o5qa6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282203/original/file-20190702-126355-9o5qa6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282203/original/file-20190702-126355-9o5qa6.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">Some of the scientific instruments built and prepared by an international team of scientists led by Prof Shadia Habbal (University of Hawaii) to observe eclipses. The team’s chief engineer, Judd Johnson, is busy fine-tuning one of the telescopes.</span>
<span class="attribution"><span class="source">Shadia Habbal</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p><a href="https://sulis.space">The spectrometer could eventually reside in space</a>, observing the solar corona continuously as part of a mission to watch the sun from a satellite. Scientists could reconstruct the corona’s magnetic field, plasma and other features to finally make sense of this extreme and mysterious environment – and help prepare Earth for its mood swings.</p>
<p>Eclipses such as 2019’s event in South America give a highly-detailed snapshot of the solar atmosphere, and offer a precious opportunity to learn about the hidden layer of the sun which can greatly affect life on Earth. It’s also relatively cheap compared to space missions, and can help scientists develop new tools for looking into space. As always, we hope for good luck, and clear skies.</p><img src="https://counter.theconversation.com/content/119349/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Huw Morgan receives funding from the Science and Technology Facilities Council (UKRI). Aberystwyth's researchers are part of an international team of eclipse chasers led by Professor Shadia Habbal from the University of Hawaii. The high-resolution spectrometer researchers at Aberystwyth use was developed by Professor Adalbert Ding from the Technische Universitaet Berlin.</span></em></p>Scientists spend years preparing for the two-minute window of a total solar eclipse.Huw Morgan, Reader in Physical Sciences, Aberystwyth UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1128862019-03-06T12:23:01Z2019-03-06T12:23:01ZOur space weather mission will venture deeper into space than any other – here’s what it could achieve<figure><img src="https://images.theconversation.com/files/261894/original/file-20190304-92280-ihwnis.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lagrange mission.</span> <span class="attribution"><span class="source">ESA/A. Baker</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>You may have noticed that some weather forecasts have started mentioning the <a href="https://aurorawatch.lancs.ac.uk/">chances of seeing an aurora</a>, also known as northern lights. Just as the atmosphere of the Earth gives us terrestrial weather, the nearby, vast atmosphere of the sun gives rise to space weather – <a href="https://theconversation.com/what-caused-those-spectacular-northern-lights-and-how-you-can-catch-them-next-time-39081">triggering events such as auroras</a>. Many weather institutes around the world now provide <a href="https://theconversation.com/why-were-preparing-weather-forecasts-in-space-32638">forecasts of the weather in space</a> because of the hazard it poses to services we rely on, such as satellite positioning services, power distribution and communications. </p>
<p>But forecasting services are only as good as the modelling and the data that underpin them. Currently, space weather forecasting satellites typically record this data from their orbit around the Earth. However, working with the UK and the European Space Agencies, we are developing a new satellite, <a href="https://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/Lagrange_mission_providing_solar_warning">dubbed Lagrange</a>, that could significantly improve space weather predictions. It will venture further away from our planet than any other dedicated space weather mission, getting a much a better view of what is going on. </p>
<p>Extreme space weather storms now feature on the <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/61934/national_risk_register.pdf">national risk registers</a> of many countries as one of the greatest natural hazards. In the UK, it comes after pandemic flu, coastal flooding and effusive volcanic eruptions. As a result, the Met Office has been monitoring space weather 24 hours a day, every day of the year, since 2014 in order to provide forecasts to a range of customers. Today, severe space weather storms are estimated to have the potential to cause <a href="https://theconversation.com/how-space-weather-poses-a-risk-to-the-finance-industry-64621">billions of pounds of damage</a> across Europe. </p>
<h2>Stable points in space</h2>
<p>Lagrange will carry all the equipment needed to characterise the activity of the sun that determine the conditions in its atmosphere. There are instruments to measure the magnitude of bursts of X-rays called <a href="https://hesperia.gsfc.nasa.gov/sftheory/flare.htm">solar flares</a> and the gusty and variable particle flows and magnetic field of the <a href="https://theconversation.com/solar-wind-and-space-dust-create-new-source-of-water-laboratory-study-suggests-22212">solar wind</a>. Others will detect gigantic eruptions of plasma known as <a href="https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections">coronal mass ejections</a> that dwarf the Earth when they arrive, with streams of particles moving at near light speed.</p>
<p>The whole suite of instruments is cleverly chosen to enable us to monitor and forecast space weather from the sun impacting on the Earth. In particular, it will measure the magnetic fields of the sun that are responsible for creating space weather in the first place and estimate how long it takes the worst space weather to reach the Earth.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/261891/original/file-20190304-92304-2hzil0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/261891/original/file-20190304-92304-2hzil0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=512&fit=crop&dpr=1 600w, https://images.theconversation.com/files/261891/original/file-20190304-92304-2hzil0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=512&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/261891/original/file-20190304-92304-2hzil0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=512&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/261891/original/file-20190304-92304-2hzil0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=643&fit=crop&dpr=1 754w, https://images.theconversation.com/files/261891/original/file-20190304-92304-2hzil0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=643&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/261891/original/file-20190304-92304-2hzil0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=643&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Lagrange points.</span>
<span class="attribution"><span class="source">wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The really new aspect of the mission though is where it will be placed. Rather than being in orbit around the Earth, the spacecraft will be sent to a “Lagrange point”. Massive objects, such as planets, have a strong gravitational field that enables us to put satellites into orbit around them. What is less well known is that that there are positions where the gravitational forces of objects such as the sun and the Earth (including the moon) and orbital motions of a spacecraft interact to create a stable location. When it comes to the sun-Earth system there are five such points, and they are called <a href="https://www.space.com/30302-lagrange-points.html">Lagrange points </a> after the Italian-French mathematician Joseph-Louis Lagrange. </p>
<p>Our mission will hover at the fifth Lagrange point (L5), sitting at one vertex of an equilateral triangle that has the sun and the Earth at its other two points. Putting a spacecraft at L5 essentially gives space weather forecasters a side-on view of the sun that will enable us to see what eruptions are heading towards the Earth. Another advantage is that the spacecraft gets to bathe in solar wind streams that will be directed at the Earth a few days later, due to the rotation of the sun. </p>
<p>Measuring the solar wind flow a few days before it points at the Earth will improve the forecast of background conditions by 50%, helping us accurately forecast an “all clear”. It will also tell us whether Earth-directed coronal mass ejections will be sped up or slowed down by the solar wind through which they move. Together with the side-on view, this will help us more accurately predict the arrival of these large eruptions at the Earth. In fact, it should double the accuracy of the forecast time compared to the current methods.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/261898/original/file-20190304-92301-a8b46s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/261898/original/file-20190304-92301-a8b46s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/261898/original/file-20190304-92301-a8b46s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/261898/original/file-20190304-92301-a8b46s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/261898/original/file-20190304-92301-a8b46s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/261898/original/file-20190304-92301-a8b46s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/261898/original/file-20190304-92301-a8b46s.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">
<figcaption>
<span class="caption">Sun after an eruption.</span>
<span class="attribution"><span class="source">ESA/ROB</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The ultimate aim of Lagrange is to improve the resilience of the planet to extreme space weather risk by enabling more accurate forecasts. However a forecast is only useful if those impacted by the hazard know what to do when an alert is issued. The academic community is supporting Lagrange by also responding to this educational space weather need, providing new teaching programmes to enable the key people to gain necessary knowledge and skills to tackle any extreme space weather events in the future. </p>
<p>Responding to extreme space weather can take many forms, but the best protection is to be prepared. If we know a major space weather event is about to happen, then satellite operators can put satellites into “safe mode” to ride out the storm. Meanwhile electricity grid operators can stabilise the grid by reducing repair work and asking high-usage customers such as factories to reduce activity. They can also keep a close eye on the performance of the high-voltage transformers at electricity substations to make sure they are not overheating. </p>
<p>Lagrange is undergoing development at the moment, but all going well it should will launch in the mid-2020s. Given the cost of space weather to our economy, it can’t come a moment too soon.</p><img src="https://counter.theconversation.com/content/112886/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lucie Green receives funding from the Royal Society. </span></em></p><p class="fine-print"><em><span>Robert Wicks receives funding from HEFCE, STFC, and UKSA. </span></em></p>The Lagrange mission could greatly improve forecasts of space weather.Lucie Green, Professor of Physics, UCLRobert Wicks, Lecturer in Space Risks, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1059832018-11-08T03:24:21Z2018-11-08T03:24:21ZBlasts from the past: how massive solar eruptions ‘probably’ detonated dozens of US sea mines<figure><img src="https://images.theconversation.com/files/243813/original/file-20181104-83635-1obzabs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Solar flares captured on the Sun.</span> <span class="attribution"><a class="source" href="https://www.nasa.gov/content/goddard/sunspot-ar2192-release-x2.0-class-solar-flare-on-oct-26-2014">NASA/SDO</a></span></figcaption></figure><p>An extraordinary account of the impact space weather had on military operations in Vietnam in 1972 was found buried in the US Navy archives, according to a newly published article in <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018SW002024">Space Weather</a>.</p>
<p>On August 4, 1972, the crew of a US Task Force 77 aircraft flying near a naval minefield in the waters off Hon La observed 20 to 25 explosions over about 30 seconds. They also witnessed an additional 25 to 30 mud spots in the waters nearby. </p>
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<a href="https://theconversation.com/its-never-been-more-important-to-keep-an-eye-on-space-weather-65648">It's never been more important to keep an eye on space weather</a>
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<p><a href="http://www.navweaps.com/Weapons/WAMUS_Mines.php#Vietnam_War_%22Destructor%22_Mines">Destructor sea mines</a> had been deployed here during Operation Pocket Money, a mining campaign launched in 1972 against principal North Vietnamese ports.</p>
<p>There was no obvious reason why the mines should have detonated. But it has now emerged the US Navy soon turned its attention to extreme solar activity at the time as a probable cause.</p>
<p>The more we can understand the impact of such space weather on technology then the better we can be prepared for any future extreme solar activity.</p>
<h2>A solar theory</h2>
<p>As detailed in a now declassified <a href="https://vva.vietnam.ttu.edu/repositories/2/digital_objects/83295">US Navy report</a>, the event sparked an immediate investigation about the potential cause(s) of the random detonations of so many sea mines. </p>
<p>The sea mines deployed had a self-destruct feature. But the minimum self-destruct time on these mines was not for another 30 days, so something else was to blame.</p>
<p>On August 15, 1972, the Commander in Chief of the US Pacific Fleet, Admiral Bernard Clarey, asked about a hypothesis that <a href="https://theconversation.com/massive-sunspots-and-huge-solar-flares-mean-unexpected-space-weather-for-earth-83677">solar activity</a> could have caused the mine detonations. </p>
<p>Many of the mines deployed were <a href="http://www.navweaps.com/index_tech/tech-068.php#Magnetic_Mines">magnetic influence sea mines</a> that were designed to detonate when they detected changes in the magnetic field. </p>
<p>Solar activity was then well known to cause <a href="https://theconversation.com/damaging-electric-currents-in-space-affect-earths-equatorial-region-not-just-the-poles-45073">magnetic field changes</a>, but it wasn’t clear whether or not the Sun could cause these unintentional detonations. </p>
<h2>Solar flares</h2>
<p>Early August in 1972 saw some of the most intense <a href="https://link.springer.com/article/10.1007%2FBF00152736">solar activity</a> ever recorded. </p>
<p>A sunspot region, denoted MR 11976, set off a series of intense <a href="https://www.space.com/11506-space-weather-sunspots-solar-flares-coronal-mass-ejections.html">solar flares</a> (energetic explosions of electromagnetic radiation), coronal mass ejections (eruptions of solar plasma material that typically accompany flares) and clouds of charged particles travelling close to the speed of light. </p>
<p>Those conducting the investigation into the mine incident visited the Space Environment Laboratory at the National Oceanographic and Atmospheric Administration (<a href="https://www.swpc.noaa.gov/">NOAA</a>) near Boulder, Colorado, to speak to space scientists.</p>
<p>One of the scientists at NOAA at the time was the now Emeritus Professor Brian Fraser, from Australia’s <a href="https://www.newcastle.edu.au/research-and-innovation/centre/csp/about-us">Newcastle University</a>, and it’s an event he told me he remembers well: </p>
<blockquote>
<p>I was on my first sabbatical leave at NOAA working with Wallace (Wally) Campbell’s group, and one day in Wally’s office I noticed a group of US Navy brass hat gentlemen and a couple of dark suits.</p>
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<p>Brian said he had later quizzed Wally on what was going on, and Wally explained they were concerned about geomagnetic field changes triggering sea mines laid in Hai Phong, North Vietnam.</p>
<blockquote>
<p>There was no mention whether or not they had exploded but maybe Wally was being coy. And of course it was all probably top secret then.</p>
</blockquote>
<p>The outcome of this investigation, as stated in the declassified US Navy <a href="https://vva.vietnam.ttu.edu/repositories/2/digital_objects/83295">report</a>, detailed “a high degree of probability” that the Destructor mines had been detonated by the August solar storm activity.</p>
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<a href="https://images.theconversation.com/files/243814/original/file-20181104-83629-171fwbu.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/243814/original/file-20181104-83629-171fwbu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/243814/original/file-20181104-83629-171fwbu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=151&fit=crop&dpr=1 600w, https://images.theconversation.com/files/243814/original/file-20181104-83629-171fwbu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=151&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/243814/original/file-20181104-83629-171fwbu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=151&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/243814/original/file-20181104-83629-171fwbu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=189&fit=crop&dpr=1 754w, https://images.theconversation.com/files/243814/original/file-20181104-83629-171fwbu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=189&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/243814/original/file-20181104-83629-171fwbu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=189&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">Declassified: excerpt from U.S. Navy Report, Mine Warfare Project Office - The Mining of North Vietnam, 8 May 1972 to 14 January 1973.</span>
<span class="attribution"><a class="source" href="https://vva.vietnam.ttu.edu/repositories/2/digital_objects/83295">1070416001, Glenn Helm Collection, The Vietnam Center and Archive, Texas Tech University</a></span>
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<h2>Solar interference</h2>
<p>Solar storms <a href="https://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html#q13">cause</a> strong magnetic field fluctuations, which impact large power grid infrastructure, particularly in the high-latitude regions beneath the northern and southern auroras. </p>
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<figcaption><span class="caption">Solar flares captured by NASA and ESA.</span></figcaption>
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<p>The storms of early August 1972 were no different. There were numerous reports across North America of <a href="https://ieeexplore.ieee.org/document/4075456">power disruptions</a> and <a href="https://ieeexplore.ieee.org/document/6773728">telegraph line outages</a>. Now that light has been shone on the impact of these events on sea mine operations in 1972, the scientific community has another clear example of space weather impacts on technologies.</p>
<p>The intensity of the early August activity peaked when an <a href="https://www.nasa.gov/mission_pages/sunearth/news/X-class-flares.html">X-class</a> solar flare at 0621 UT August 4, 1972, launched an ultra-fast coronal mass ejection that reached Earth in the record time of 14.6 hours. The solar wind normally takes two to three days to reach Earth. </p>
<p>Scientists think that the previous slower ejections from earlier flares had cleared the path for this fast disturbance, similar to what was observed by the <a href="https://stereo.gsfc.nasa.gov/">STEREO</a> spacecraft in <a href="https://theconversation.com/solar-eruption-could-help-earth-prepare-for-technology-melt-down-18747">July 2012</a>.</p>
<p>It’s the impact of this fast disturbance in the solar wind on the Earth’s magnetosphere that <a href="https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2018SW002024">probably caused</a> the detonation of the Destructor mines.</p>
<h2>Using the past to predict the future</h2>
<p>The <a href="http://wdc.kugi.kyoto-u.ac.jp/dst_realtime/presentmonth/index.html">Dst index</a>, measured in nano-Tesla (nT), is a typical measure of the disturbance level in the Earth’s magnetic field – the more negative, the more intense the storm. </p>
<p>Some recent extreme solar storms, according to this scale, include the 2015 St Patrick’s Day storm (<a href="http://wdc.kugi.kyoto-u.ac.jp/dst_provisional/201503/index.html">-222 nT</a>) and the 2003 Halloween storm (<a href="http://wdc.kugi.kyoto-u.ac.jp/dst_final/200310/index.html">-383 nT</a>).</p>
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Read more:
<a href="https://theconversation.com/what-the-weather-is-like-on-a-star-can-help-in-the-search-for-life-56275">What the 'weather' is like on a star can help in the search for life</a>
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<p>Interestingly, the extreme activity in August 1972 was far less intense on this scale, only weighing in at <a href="http://wdc.kugi.kyoto-u.ac.jp/dst_final/197208/index.html">-125 nT</a>. </p>
<p>Exactly why this storm reached extreme level on some measures, such as its high speed from the Sun, but not on the typical Dst scale is a topic of significant discussion within the scientific <a href="https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/91GL02783">literature</a>.</p>
<p>Given the complexities of this event, <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018SW002024">this new paper</a> lays out a grand challenge to the space weather community to use our modern modelling techniques to reexamine this solar event. Hopefully, understanding these strange events will better prepare us for future solar eruptions.</p><img src="https://counter.theconversation.com/content/105983/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brett Carter receives funding from the Australian Research Council and the Australian Antarctic Science Program. </span></em></p>When dozens of US mines planted in waters off the Vietnam coast detonated almost simultaneously in 1972, all eyes turned to the Sun for an explanation.Brett Carter, Senior lecturer, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1047192018-10-17T13:09:13Z2018-10-17T13:09:13ZHow a group of school students discovered the sounds of solar storms<figure><img src="https://images.theconversation.com/files/241021/original/file-20181017-41156-1bho8cf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Solar winds make the Earth's magnetic field crunch and whistle.</span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>We are now truly living in the era of big data. And it’s not just companies like Facebook and YouTube that are reaping the benefits, big data is transforming science too. In the space sciences, we have an unprecedented number of satellites and ground-based instruments that monitor Earth’s space environment – routinely producing tonnes of data. But how do you process it all? While you may have heard about algorithms and artificial intelligence, there are some decidedly more human approaches too.</p>
<p>One of the things I study are the sounds within the Earth’s magnetosphere – the magnetic bubble that protects us from space radiation. These sounds consist of particles vibrating back and forth. Because they are electrically charged, they are affected by magnetic fields, but can also themselves affect magnetic fields, such as those from the Earth, to create a <a href="https://theconversation.com/you-are-living-inside-a-massive-musical-instrument-and-heres-what-it-sounds-like-72992">magnetic type of sound waves</a>. However, since there are so few particles in space, these sounds <a href="https://theconversation.com/what-does-empty-space-sound-like-we-need-your-help-to-find-out-69252">are incredibly weak</a> and only present at frequencies thousands of times lower than we can hear.</p>
<p>We can, however, make our recordings of them audible simply by amplifying them and dramatically speeding them up. This latter part can help with big data – you can get through a whole year’s worth of these recordings by just listening to six minutes of audio. And by doing this, we identified the sounds that follow solar storms. Our results <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018SW001988">were published</a> in Space Weather.</p>
<p>But we didn’t do it alone. One way scientists have been trying to cope with big data is by using <a href="https://theconversation.com/explainer-what-is-citizen-science-16487">citizen science</a>, crowdsourcing volunteers from the public to carry out well-defined tasks that help classify or analyse datasets that would be difficult to do using a computer or a lone scientist. </p>
<p>This has proven incredibly successful. For example, the 1.6m users of the citizen science platform <a href="https://www.zooniverse.org/">Zooniverse</a> have managed to achieve 375m classifications – ranging from distant galaxies to marine invertebrates. However, with these projects, the scientists who set them up have to have an idea of what they’re looking for. It’s highly likely though that there are phenomena hidden in the data that we are currently missing because we don’t know how to look for it yet.</p>
<h2>Citizen science 2.0</h2>
<p>I had the idea that we could combine these two approaches, having lots of people listening to sounds from space and seeing if anything interesting turned up. And now it has, with our new study revealing the sounds that follow solar storms, found thanks to a group of A-level school students in London. What the students discovered was a loud crunching noise followed by a series of whistling sounds whose pitch decreased. This event in the audio, lasting five or six seconds, corresponded to several days in reality.</p>
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<p>By looking into these unexpected sounds in more detail, we found that they started just as a “coronal mass ejection” or solar storm hit Earth’s magnetosphere, which caused a big disturbance. Such disturbances are important because they can adversely affect technology such as communications satellites and power grids, <a href="https://theconversation.com/why-were-preparing-weather-forecasts-in-space-32638">known as space weather</a>.</p>
<p>It turned out that the whistling sounds were vibrations of Earth’s magnetic field lines – a bit like the vibrations of a guitar string can form a note. While the solar storm stripped away many of the particles present in Earth’s space environment, they started to refill again from the top of the atmosphere as it recovered. It was this refilling that caused the pitch of the sounds to drop slowly over time.</p>
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<p>Space scientists had barely discussed sounds like this before – they were thought to be incredibly rare. We wanted to find out whether that was actually the case by taking a closer look at our audible dataset. What we found is that similar sounds are in fact quite common following solar storms – in 2013, the year of the first event, 20 others occurred.</p>
<p>By looking in more detail at these whistling sounds, we hope to better understand the recovery process of Earth’s magnetosphere during other space weather events. In particular, knowing which classes of solar storms and other phenomena lead to these sounds will allow us to figure out not only how effective they are at driving space weather, but conversely how all that energy gets dissipated during the recovery. By building up a better picture of what happens, we may one day <a href="https://theconversation.com/the-scorching-winds-on-the-surface-of-the-sun-and-how-were-forecasting-them-44098">improve our forecasting</a>.</p>
<p>As our research shows, citizen science can clearly turn up interesting and unexpected scientific results. But that’s not all – it can also create art. Today also sees the release of an anthology of short films, created by independent filmmakers from across the globe, all of which were inspired by and incorporate these sounds. You can <a href="https://www.youtube.com/watch?v=P5_OljSnA1k">watch it online</a> for free.</p><img src="https://counter.theconversation.com/content/104719/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin Archer has received funding from the Science and Technology Facilities Council and the European Geosciences Union.</span></em></p>The Earth’s magnetic field lines whistle after solar outbursts.Martin Archer, Space Plasma Physicist, Queen Mary University of LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/927112018-03-29T10:29:39Z2018-03-29T10:29:39ZSpace weather threatens high-tech life<figure><img src="https://images.theconversation.com/files/212007/original/file-20180326-159081-ibu4ks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A coronal mass ejection erupts from the sun in 2012.</span> <span class="attribution"><a class="source" href="https://svs.gsfc.nasa.gov/11095">NASA</a></span></figcaption></figure><p>Shortly after 4 a.m. on a crisp, cloudless September morning in 1859, the sky above what is currently Colorado erupted in bright red and green colors. Fooled by the brightness into <a href="https://arstechnica.com/science/2012/05/1859s-great-auroral-stormthe-week-the-sun-touched-the-earth/">thinking it was an early dawn</a>, gold-rush miners in the mountainous region of what was then called the Kansas Territory woke up and started making breakfast. What happened in more developed regions was even more disorienting, and carries a warning for the wired high-tech world of the 21st century.</p>
<p>As the sky lit up over the nighttime side of the Earth, <a href="https://io9.gizmodo.com/how-the-carrington-event-let-telegraphs-run-on-aurora-p-1686759750">telegraph systems worldwide went berserk</a>, clacking nonsense code and emitting large sparks that ignited fires in nearby piles of paper tape. Telegraph operators <a href="https://science.nasa.gov/science-news/science-at-nasa/2008/06may_carringtonflare">suffered electrical burns</a>. Even disconnecting the telegraph units from their power sources <a href="https://science.nasa.gov/science-news/science-at-nasa/2008/06may_carringtonflare">didn’t stop the frenzy</a>, because the transmission wires themselves were carrying huge electrical currents. Modern technology had just been humbled by a fierce space weather storm that had arrived from the sun, the <a href="http://doi.org/10.1029/2011SW000734">largest ever recorded</a> – and more than twice as powerful as a storm nine years earlier, which had itself been the largest in known history.</p>
<p>My seven years of research on predicting solar storms, combined with my decades using GPS satellite signals under <a href="http://www.cis.rit.edu/%7Errdpci/space-weather.html">various solar storm conditions</a>, indicate that today’s even more sensitive electronics and satellites would be devastated should an event of that magnitude occur again. In 2008, a panel of experts commissioned by the National Academy of Sciences issued a detailed report with a sobering conclusion: The world would be <a href="https://www.nap.edu/catalog/12643/severe-space-weather-events-understanding-societal-and-economic-impacts-a">thrown back to the life of the early 1800s</a>, and it would take years – or even a decade – to recover from an event that large. </p>
<h2>A solar explosion</h2>
<p>Space weather storms have happened since the birth of the solar system, and have <a href="https://arxiv.org/ftp/arxiv/papers/0902/0902.3446.pdf">hit Earth many times</a>, both before and after that massive event in 1859, which was named the <a href="https://arstechnica.com/science/2012/05/1859s-great-auroral-stormthe-week-the-sun-touched-the-earth/">Carrington event</a> after a British astronomer who <a href="http://www.solarstorms.org/SCarrington.html">recorded his observations of the sun</a> at the time. They’re caused by huge electromagnetic explosions on the surface of the sun, called <a href="https://www.swpc.noaa.gov/phenomena/coronal-mass-ejections">coronal mass ejections</a>. Each explosion sends billions of protons and electrons, in a <a href="http://pluto.space.swri.edu/image/glossary/plasma.html">superheated ball of plasma</a>, out into the solar system.</p>
<p><a href="https://spacemath.gsfc.nasa.gov/weekly/3Page27.pdf">About 1 in every 20</a> coronal mass ejections heads in a direction that <a href="https://theconversation.com/how-facebook-the-wal-mart-of-the-internet-dismantled-online-subcultures-71536">intersects Earth’s orbit</a>. <a href="https://www.spaceweatherlive.com/en/help/how-do-we-know-if-a-cme-is-earth-directed-and-when-its-going-to-arrive">Around three days later</a>, our planet experiences what is called a space weather storm or a geomagnetic storm. </p>
<p>While these events are described using terms like “weather” and “storm,” they do not affect whether it’s rainy or sunny, hot or cold, or other aspects of what it’s like outdoors on any given day. Their effects are not meteorological, but only electromagnetic. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/212010/original/file-20180326-159081-14mbyu0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/212010/original/file-20180326-159081-14mbyu0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/212010/original/file-20180326-159081-14mbyu0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/212010/original/file-20180326-159081-14mbyu0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/212010/original/file-20180326-159081-14mbyu0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/212010/original/file-20180326-159081-14mbyu0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/212010/original/file-20180326-159081-14mbyu0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/212010/original/file-20180326-159081-14mbyu0.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">Aurorae are signs of a geomagnetic storm.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/image-feature/goddard/2017/northern-lights-over-alaska-2">NASA/Terry Zaperach</a></span>
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<h2>Hitting Earth</h2>
<p>When the coronal mass ejection arrives at Earth, the charged particles collide with air molecules in the upper atmosphere, generating heat and <a href="https://www.timeanddate.com/astronomy/northern-southern-lights.html">light called aurora</a>.</p>
<p>Also, as happens anytime <a href="https://www.youtube.com/watch?v=DVcvKwEUYqk">moving electrical charges encounter a magnetic field</a>, the interaction creates a spontaneous electrical current in any conductor that’s available. If the plasma ball is big enough, its interaction with Earth’s magnetic field can induce <a href="https://doi.org/10.1002/swe.20065">large currents on long wires</a> on the ground, like the one that overloaded telegraph circuits in 1859.</p>
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<p>On March 13, 1989, a storm only about <a href="https://www.swpc.noaa.gov/noaa-scales-explanation">one-fifth as strong</a> as the Carrington event hit Earth. It induced a large surge of current in the long power lines of the <a href="http://www.hydroquebec.com/learning/notions-de-base/tempete-mars-1989.html">Hydro-Quebec power grid</a>, causing physical damage to transmission equipment and leaving <a href="https://www.scientificamerican.com/article/geomagnetic-storm-march-13-1989-extreme-space-weather/">6 million people without power for nine hours</a>. Another storm-induced power surge <a href="https://spectrum.ieee.org/energy/the-smarter-grid/a-perfect-storm-of-planetary-proportions">destroyed a large transformer</a> at a New Jersey nuclear plant. Even though a spare transformer was nearby, it still took <a href="http://www.solarstorms.org/SWChapter1.html">six months to remove and replace</a> the melted unit. Some people worried that the bright auroral lights meant <a href="https://www.washingtonpost.com/news/capital-weather-gang/wp/2017/06/08/trumps-budget-eliminates-program-that-detects-infrastructure-crippling-solar-storms/">nuclear war had broken out</a>.</p>
<p>And in October 2003, a rapid series of solar storms affected Earth. Collectively called the Halloween solar storm, this series <a href="https://www.nasa.gov/topics/solarsystem/features/halloween_storms.html">caused surges</a> that <a href="https://www.directionsmag.com/article/1510">threatened the North American power grid</a>. Its <a href="https://www.space.com/23396-scary-halloween-solar-storm-2003-anniversary.html">effects on satellites</a> made GPS navigation erratic and interrupted communications connections during the peak of the storm.</p>
<p>Larger storms will have wider effects, cause more damage and take longer to recover from.</p>
<h2>Wide-reaching effects</h2>
<p>Geomagnetic storms attack the lifeblood of modern technology: electricity. A space weather storm typically lasts for two or three days, during which the entire planet is subjected to powerful electromagnetic forces. The <a href="https://www.nap.edu/catalog/12643/severe-space-weather-events-understanding-societal-and-economic-impacts-a">National Academy of Sciences study</a> concluded that an especially massive storm would damage and shut down power grids and communications networks worldwide.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/209611/original/file-20180308-30961-ghoyz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/209611/original/file-20180308-30961-ghoyz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/209611/original/file-20180308-30961-ghoyz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/209611/original/file-20180308-30961-ghoyz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/209611/original/file-20180308-30961-ghoyz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/209611/original/file-20180308-30961-ghoyz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/209611/original/file-20180308-30961-ghoyz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/209611/original/file-20180308-30961-ghoyz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Electricity, shown in the upper right, is integrated into every aspect of modern life.</span>
<span class="attribution"><a class="source" href="https://www.fcc.gov/help/public-safety-tech-topic-19-communications-interdependencies">Federal Communications Commission</a></span>
</figcaption>
</figure>
<p>After the storm passed, there would be no simple way to restore power. Manufacturing plants that build replacements for burned-out lines or power transformers would have no electricity themselves. Trucks needed to deliver raw materials and finished equipment wouldn’t be able to fuel up, either: Gas pumps run on electricity. And what pumps were running would soon dry up, because electricity also runs the machinery that extracts oil from the ground and refines it into usable fuel. </p>
<p>With transportation stalled, food wouldn’t get from farms to stores. Even systems that seem non-technological, like public water supplies, would shut down: Their pumps and purification systems need electricity. People in developed countries would find themselves with no running water, no sewage systems, no refrigerated food, and no way to get any food or other necessities transported from far away. People in places with more basic economies would also be without needed supplies from afar.</p>
<p>It could take <a href="https://www.nap.edu/catalog/12643/severe-space-weather-events-understanding-societal-and-economic-impacts-a">between four and 10 years</a> to repair all the damage. In the meantime, people would need to grow their own food, find and carry and purify water, and cook meals over fires.</p>
<p>Some systems would continue to operate, of course: bicycles, horse-drawn carriages and sailing ships. But another type of equipment that would keep working provides a clue to preventing this type of disaster: Electric cars would continue to work, but only in places where there were solar panels and wind turbines to recharge them.</p>
<h2>Preparing and protecting</h2>
<p>Geomagnetic storms would affect those small-scale installations far less than grid-scale systems. It’s a basic principle of electricity and magnetism that the longer a wire that’s exposed to a moving magnetic field, the <a href="https://doi.org/10.1016/S1364-6826(02)00126-8">larger the current that’s induced</a> in that wire.</p>
<p>In 1859, the telegraph system was so profoundly affected because it had wires stretching from city to city across the U.S. Those very long wires had to handle enormous amounts of energy all at once, and failed. Today, there are long runs of wires connecting power generators to consumers – such as <a href="https://www.eia.gov/todayinenergy/detail.php?id=27152">from Niagara Falls to New York City</a> – that would be similarly susceptible to large induced currents.</p>
<p>The only way to reduce vulnerability to geomagnetic storms is to substantially revamp the power grid. Now, it is a <a href="https://www.eia.gov/todayinenergy/detail.php?id=27152">vast web of wires</a> that effectively spans continents. Governments, businesses and communities need to work together to split it into much smaller components, each serving a town or perhaps even a neighborhood – or an individual house. These “<a href="https://www.energy.gov/articles/how-microgrids-work">microgrids</a>” can be connected to each other, but should have <a href="https://science.nasa.gov/science-news/science-at-nasa/2010/26oct_solarshield">protections built in</a> to allow them to be disconnected quickly when a storm approaches. That way, the length of wires affected by the storm will be shorter, reducing the potential for damage.</p>
<p>A family using solar panels and batteries for storage and an electric car to get around would likely find its water supply, natural gas or internet service disrupted. But their freedom to travel, and to use electric lights to work after dark, would provide a much better chance at survival.</p>
<h2>When will the next storm hit?</h2>
<p>People should start preparing today. It’s impossible to know when a major storm will hit next: The most we’ll get is a <a href="https://theconversation.com/new-solar-storm-forecasting-technique-breaks-the-24-hour-warning-barrier-for-earth-42917">three-day warning</a> when something happens on the surface of the sun. It’s really only a matter of time before there is another one like the Carrington event.</p>
<p><a href="https://doi.org/10.1063/1.4993929">Solar astrophysicists</a> are also studying the sun to identify any events or conditions that might herald a coronal mass ejection. They’re collecting enormous amounts of data about the sun and using computer analysis to try to connect that information to geomagnetic storms on Earth. This work is underway and will become more refined over time. The research has not yet yielded a reliable prediction of a coming solar storm before an ejection occurs, but it improves each year. </p>
<p>In my view, the safest course of action involves developing microgrids based on renewable energy. That would not only improve people’s quality of life around the planet right now, but also provide the best opportunity to maintain that lifestyle when adverse events happen.</p><img src="https://counter.theconversation.com/content/92711/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roger Dube has previously received funding from the National Aeronautics and Space Administration (NASA). </span></em></p>The wired Earth of the 21st century is at the mercy of the volatile nature of the sun.Roger Dube, Research Professor of Imaging Science, Rochester Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/923852018-02-28T18:49:18Z2018-02-28T18:49:18Z‘Beast from The East’ – the science behind Europe’s Siberian chill<figure><img src="https://images.theconversation.com/files/208297/original/file-20180228-36706-185c0cg.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://twitter.com/NPASLondon/status/968522249711116288">National Police Air Service</a></span></figcaption></figure><p>The so-called “Beast from the East” has arrived in the UK, bringing unusually cold weather – <a href="https://www.accuweather.com/en/gb/london/ec4a-2/february-weather/328328">about 7°C colder</a> than the historical average for this time of year. Wind chill is making temperatures feel particularly arctic. So how did the Siberian gusts come to arrive on Europe’s doorstep?</p>
<p>The movement of air across the globe, and the weather it brings with it, is governed by three major influences: gravity, the sun, and something called the <a href="https://www.metoffice.gov.uk/learning/learn-about-the-weather/how-weather-works/coriolis-effect">Coriolis effect</a>. The influence of gravity is simple, constantly pulling air towards the Earth’s surface.</p>
<p>The rise and fall of the sun dictates whether the air stays there. During the day, radiation from the sun heats the Earth, warming air directly above the surface and causing it to rise, leaving behind a region of low pressure (a low density of air particles). As the air rises, it cools and spreads outwards. This mass of air, now denser than the air below it, sinks back down under the force of gravity, and naturally flows back towards the lower pressure region of air, creating a cycle of air circulation. These circulating patterns of wind exist <a href="https://www.metoffice.gov.uk/learning/learn-about-the-weather/how-weather-works/global-circulation-patterns">on an intercontinental scale</a>, transporting heat all the way from the tropics to the poles.</p>
<p>However, thanks to the <a href="https://www.metoffice.gov.uk/learning/learn-about-the-weather/how-weather-works/coriolis-effect">Coriolis effect</a> – the deflection of objects moving in a straight path due to the Earth’s rotation – the winds do not travel directly north or south. To illustrate this effect, imagine a spinning top. Parts of the spinning top closer to the spindle rotate at slower speeds than parts further away, as they have less distance to travel to complete a full circle. Similarly, the equator <a href="http://www.physicstutorials.org/home/rotational-motion/tangential-speed-velocity">has to travel much faster than the poles do</a> as the Earth rotates. As air travels north from the equator, its extra momentum compared to the slower rotating land that it is moving over makes it curve across to the east, while air travelling to the south pole curves westward.</p>
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<p>In the northern hemisphere, this interaction between the Coriolis effect and the circulation systems produces the <a href="https://www.metoffice.gov.uk/learning/wind/what-is-the-jet-stream">northern polar jet stream</a>: high altitude currents of air blowing eastwards at hundreds of miles per hour, moving weather systems around the globe. This causes the UK’s prevailing westerly and south-westerly winds, which usually draw weather systems in from the relatively warm Atlantic and shield us from colder air masses to the east.</p>
<p>The shape of the jet streams is not rigid – it follows a meandering path, much like a slithering snake. Occasionally, the jet stream path can become so twisted that it folds back upon itself, reversing the direction of the prevailing wind, and drawing in cold air from the east. <a href="https://theconversation.com/beast-from-the-east-and-freakishly-warm-arctic-temperatures-are-no-coincidence-92774">A complex cascade of events</a> associated with a phenomenon called Stratospheric Sudden Warming led to exactly this happening. In the last couple of days, the bitterly cold front combined with water vapour in the air to carpet the country in a blanket of brilliant white. </p>
<p>As the warmth of the sun disappears each night, the cold can feel all the more biting. But in the absence of the sun’s heat, the smaller difference in temperature between air near the ground and higher up makes air circulate more slowly. This often creates calmer conditions that might just provide a brief respite from the extra chill of the wind. For this same reason, air passengers generally experience <a href="https://www.skyscanner.net/news/guide-turbulence">smoother flying conditions when flying at night</a>.</p>
<p>If you live in the city however, your experience of the “beast” can vary wildly from place to place. Cities continue to produce heat at night, <a href="https://www.nationalgeographic.org/encyclopedia/urban-heat-island/">generating their own microclimates</a>. This man-made heat keeps air moving, and warms city dwellers up more than those in rural areas. At the same time, the ordered formation of buildings in cities <a href="http://urban-climate.org/documents/TonyChandler_TheClimateOfLondon.pdf">creates strong wind corridors</a> that are certainly best avoided at times like these.</p>
<p>Wherever you are experiencing this freezing weather, you can at least be thankful that you are here on Earth. Wind circulation patterns on other planets produce far more extreme weather than we will ever experience. Visitors to Venus, for example, would experience some serious turbulence when approaching landing, as <a href="http://venus.aeronomie.be/en/venus/temperaturegreenhouseeffect.htm">the 500°C difference between surface and cloud</a> generates extreme air circulation. </p>
<p>However, if you were lucky enough to touch down and survive the experience of the crushing pressure found on Venus’ surface, you would feel nothing more than a gentle breeze, thanks to the planet’s very slow rotation, weak Coriolis effect, and dense air. You might want to seek shelter though – at close to 460°C, suddenly a cold chill doesn’t seem so bad.</p><img src="https://counter.theconversation.com/content/92385/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gareth Dorrian receives funding from Nottingham Trent University and has previously received research support funding from the Natural Environment Research Council. </span></em></p><p class="fine-print"><em><span>Ian Whittaker 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>No matter how cold it is, you’re lucky you don’t live on Venus.Gareth Dorrian, Post Doctoral Research Associate in Space Science, Nottingham Trent UniversityIan Whittaker, Lecturer, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/836772017-09-08T00:18:31Z2017-09-08T00:18:31ZMassive sunspots and huge solar flares mean unexpected space weather for Earth<figure><img src="https://images.theconversation.com/files/185178/original/file-20170907-9585-c1fei2.jpg?ixlib=rb-1.1.0&rect=183%2C0%2C1615%2C1074&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A huge solar flare flashes in the middle of the sun on Sept. 6, 2017. A separate image of the Earth provides scale.</span> <span class="attribution"><a class="source" href="https://svs.gsfc.nasa.gov/12706">NASA/GSFC/SDO</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>If you still have your solar viewing glasses from the eclipse, now is a good time to slap them on and look up at the sun. You’ll see two big dark areas visible on our star. These massive sunspots are regions of intense and complicated magnetic fields that can produce solar flares – bursts of high-energy radiation. You can just make them out with solar viewing glasses, but they’re better viewed through a solar telescope. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"905107565406818304"}"></div></p>
<p>These two huge sunspots are currently causing quite a bit of consternation and interest. The solar storms they’ve sent toward Earth may affect communications and other technologies like GPS and radio signals. They’re causing amazing displays of the Northern and Southern Lights. And space weather scientists like us are excited because we wouldn’t normally expect this much activity from the sun at the moment.</p>
<p>The sun goes through 11-year cycles of solar activity. What scientists call a solar maximum is the time in the cycle when the sun is putting out the most energy. That’s when we tend to see the most sunspots, solar flares and associated solar storms. Some solar maxima are larger or more active than others – such as the 1990-1991 solar max. But this last cycle, which peaked in 2014, was <a href="https://solarscience.msfc.nasa.gov/predict.shtml">quite small</a>, and there were few large geomagnetic storms.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/185117/original/file-20170907-9538-1uarzku.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185117/original/file-20170907-9538-1uarzku.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185117/original/file-20170907-9538-1uarzku.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185117/original/file-20170907-9538-1uarzku.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185117/original/file-20170907-9538-1uarzku.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185117/original/file-20170907-9538-1uarzku.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185117/original/file-20170907-9538-1uarzku.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185117/original/file-20170907-9538-1uarzku.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The number of sunspots varies over the years, but you’d expect to see more during solar maxima and fewer during solar minima.</span>
<span class="attribution"><a class="source" href="http://www.swpc.noaa.gov/products/goes-x-ray-flux">NOAA</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We’re heading into the bottom of solar minimum, when the sun tends to have fewer sunspots, <a href="https://www.nasa.gov/content/goddard/the-difference-between-flares-and-cmes">solar flares</a> and <a href="http://www.swpc.noaa.gov/phenomena/coronal-mass-ejections">coronal mass ejections</a> – large <a href="http://earthsky.org/space/what-are-coronal-mass-ejections">expulsions of plasma, electrons and ions, and magnetic fields</a>. But despite where we are in the sun’s cycle, activity on the sun has dramatically picked up over the past few days. On and off, these two sunspots have been flaring and shooting out coronal mass ejections, directed toward Earth.</p>
<p>So what’s going on with the sun? And should we be concerned about this somewhat out-of-character solar behavior?</p>
<h2>Here’s what’s happened so far</h2>
<p>On September 4, the sun started sputtering. A moderately large flare (<a href="https://www.nasa.gov/mission_pages/sunearth/news/classify-flares.html">classified as an M5.5</a>) erupted at approximately 18:30 UTC. It produced a coronal mass ejection aimed at Earth.</p>
<p>The sun continued to flare on September 5. A <a href="https://helios.gsfc.nasa.gov/sep.html">solar energetic particle</a> event from the previous day’s activity arrived at the Earth, where it likely affected radio communications as well as the health of satellite systems.</p>
<p>On September 6, the sun produced two massive <a href="https://www.nasa.gov/mission_pages/sunearth/news/X-class-flares.html">X-class flares</a>. This is the category for the strongest of all solar flares.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"905456884911661057"}"></div></p>
<p>NASA announced one was <a href="https://www.nasa.gov/feature/goddard/2017/active-region-on-sun-continues-to-emits-solar-flares">the most powerful since at least 2008</a>. It <a href="https://twitter.com/NASASun/status/905822026488619008">produced another coronal mass ejection</a>.</p>
<figure class="align-center zoomable">
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<figcaption>
<span class="caption">The second and strongest of the two X-class flares on September 6 produced a coronal mass ejection directed at Earth.</span>
<span class="attribution"><span class="source">NOAA</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Over the next day, the same sunspots continued to spit out more solar flares. It took about an hour for the <a href="https://helios.gsfc.nasa.gov/sep.html">solar energetic particles</a> they emitted to arrive at Earth. These protons are incredibly fast-moving. They can affect communication systems, typically in the polar regions where they are more likely to enter into the Earth’s atmosphere. As with all increases of radiation in space, they can also affect satellite systems and the health of astronauts. </p>
<p>Early in the morning hours of September 7 in the U.S., that first coronal mass ejection that erupted from the sun three days earlier arrived at Earth. Because of the way its magnetic field aligned with Earth’s, it <a href="http://wdc.kugi.kyoto-u.ac.jp/dst_realtime/201709/index.html">generated only a small geomagnetic storm</a>.</p>
<p>After being detected by spacecraft upstream from Earth in the solar wind, the massive coronal mass ejection from September 6 also hit Earth on the evening of September 7 EDT. Its arrival was a few hours earlier than <a href="http://www.swpc.noaa.gov/products/wsa-enlil-solar-wind-prediction">space weather forecasting agencies</a> around the world predicted.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/185185/original/file-20170907-9603-8u5a2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185185/original/file-20170907-9603-8u5a2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185185/original/file-20170907-9603-8u5a2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185185/original/file-20170907-9603-8u5a2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185185/original/file-20170907-9603-8u5a2w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185185/original/file-20170907-9603-8u5a2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185185/original/file-20170907-9603-8u5a2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185185/original/file-20170907-9603-8u5a2w.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">Both sunspots are visible on the sun’s surface, as well as the flare in the solar atmosphere.</span>
<span class="attribution"><a class="source" href="https://svs.gsfc.nasa.gov/12706">NASA/GSFC/SDO</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>What other effects will Earth see?</h2>
<p>All this solar activity has already caused a couple of radiation storms in Earth’s high latitude regions that <a href="http://www.swpc.noaa.gov/phenomena/solar-flares-radio-blackouts">blacked out radio communication</a> at certain frequencies. The impacts extended toward the equator and have affected high-frequency communications, including ham radios, which are used in emergency and disaster relief management. Radio fade-out maps from the <a href="http://www.sws.bom.gov.au/HF_Systems/6/2/2">Australian Bureau of Meteorology</a> show that <a href="http://www.swpc.noaa.gov/communities/radio-communications">high-frequency radio communication disruptions</a> have likely occurred in the same areas being pummeled by Hurricane Irma.</p>
<p>There has likely been a <a href="https://www.engadget.com/2017/09/07/a-huge-solar-flare-temporarily-knocked-out-gps-communications/">loss of global navigation system satellite communications</a> in those same areas, but it will take time for the data to be analyzed and for us to gain a full understanding of how this space weather activity has affected those on the ground. The <a href="https://theconversation.com/are-you-a-frequent-flyer-solar-storm-radiation-can-be-harmful-28775">radiation storms</a> may also force flights over the polar regions to reroute to avoid increased radiation exposures for people on board and potential loss of communication and navigation systems for aircraft on these paths. </p>
<p>With the collision of the coronal mass ejection from this X-class flare with Earth come other impacts for the near-Earth space environment. <a href="https://theconversation.com/divert-power-to-shields-the-solar-maximum-is-coming-11228">Geomagnetic storms</a>, like the one currently in progress, are known to wreak havoc on a range of satellite and ground-based communication technologies, as well as <a href="https://theconversation.com/damaging-electric-currents-in-space-affect-earths-equatorial-region-not-just-the-poles-45073">power grids</a>, GPS/GNSS, and orbit predictions of satellites and space debris. It is also very likely to produce dazzling aurora activity as far south as the northern U.S. and Europe in the Northern Hemisphere, and as far north as southern Australia and New Zealand in the Southern Hemisphere. </p>
<p>While scientists and aurora-hunting enthusiasts closely watch the storm’s ongoing effects, others will be bracing for problems and disruptions to the many technological services that will be affected.</p>
<p>We don’t need to worry about this coronal mass ejection being “the big one” – a solar storm direct hit that could cause widespread power blackouts and trigger <a href="https://science.nasa.gov/science-news/science-at-nasa/2014/23jul_superstorm/">as much as US$2 trillion worth of damage</a>, according to a National Academy of Sciences study. But this storm, on the back of this month’s abnormally active space weather, may wind up on the larger end of the scale, and will be the subject of lots of analysis and research.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/185120/original/file-20170907-9568-1nt2u26.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185120/original/file-20170907-9568-1nt2u26.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185120/original/file-20170907-9568-1nt2u26.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185120/original/file-20170907-9568-1nt2u26.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185120/original/file-20170907-9568-1nt2u26.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185120/original/file-20170907-9568-1nt2u26.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185120/original/file-20170907-9568-1nt2u26.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185120/original/file-20170907-9568-1nt2u26.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Images of the sun during solar cycle 23. You typically see more activity during a solar maximum (2001) than during a minimum (1996 or 2006).</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/mission_pages/sunearth/science/solarcycle23.html">ESA&NASA/SoHO</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We don’t yet fully understand everything that is happening. But the activity over the past few days, when the sun should be within its quietest period, shows that significant space weather events are possible at any stage of the 11-year solar cycle.</p>
<p>You can help us study this and other solar storms as a citizen scientist. Sign up for <a href="http://www.aurorasaurus.org/">Aurorasaurus</a> and let us know if you observe aurorae with this event.</p><img src="https://counter.theconversation.com/content/83677/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexa Halford receives funding from NASA. </span></em></p><p class="fine-print"><em><span>Brett Carter receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Julie Currie receives funding from the Australian Research Council. </span></em></p>At a time in the sun’s cycle when space weather experts expect less solar activity, our star is going bonkers with solar flares and coronal mass ejections. What effects will Earth feel?Alexa Halford, Researcher in Physics and Astronomy, Dartmouth CollegeBrett Carter, Senior Research Fellow, RMIT UniversityJulie Currie, Research Officer, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/835202017-09-06T08:27:25Z2017-09-06T08:27:25ZWhale strandings: could solar storms that cause the northern lights be to blame?<p>A series of sperm whale strandings saw 29 of the animals beached across the North Sea in early 2016. As these whales are not normally found in the North Sea, the strandings were a <a href="https://theconversation.com/explainer-what-do-we-know-about-why-whales-strand-themselves-4323">bit of a mystery</a>. But a <a href="https://www.cambridge.org/core/journals/international-journal-of-astrobiology/article/solar-storms-may-trigger-sperm-whale-strandings-explanation-approaches-for-multiple-strandings-in-the-north-sea-in-2016/C70B7A535EFA936C0449C1730B647A74#">study</a> is now proposing that the solar storms that cause the northern and southern lights (aurora) could be to blame for the <a href="https://theconversation.com/dead-whales-are-expensive-whose-job-is-it-to-clear-them-up-37528">ill-fated whales</a> ending up on the beaches.</p>
<p>In their seasonal migrations between warmer equatorial waters and the squid-rich Norwegian Sea, sperm whales generally don’t travel through the North Sea. Instead, they migrate along the western coast of the British Isles. The North Sea is far too shallow for the whales and their favourite squid prey (<em>Gonatus fabricii</em>) generally isn’t found there either. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/184747/original/file-20170905-13755-1fzhzjg.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/184747/original/file-20170905-13755-1fzhzjg.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=752&fit=crop&dpr=1 600w, https://images.theconversation.com/files/184747/original/file-20170905-13755-1fzhzjg.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=752&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/184747/original/file-20170905-13755-1fzhzjg.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=752&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/184747/original/file-20170905-13755-1fzhzjg.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=944&fit=crop&dpr=1 754w, https://images.theconversation.com/files/184747/original/file-20170905-13755-1fzhzjg.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=944&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/184747/original/file-20170905-13755-1fzhzjg.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=944&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">North Sea map.</span>
<span class="attribution"><span class="source">Halava/wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>So once the whales entered the North Sea, it’s likely that they became disorientated, <a href="https://theconversation.com/what-causes-whale-mass-strandings-72985">trapped in the shallow waters</a> and ultimately beached. <a href="http://www.sciencedirect.com/science/article/pii/S0025326X16306592">Necropsies performed on the whales</a> suggested that they were healthy and well nourished, and so why they had entered the North Sea at all was a mystery.</p>
<p>It is thought that some animals can get a <a href="https://theconversation.com/explainer-how-do-homing-pigeons-navigate-25633">sense of direction</a> from the Earth’s magnetic field. Indeed, cetaceans, which includes whales and dolphins, are thought to be able to navigate using “<a href="https://theconversation.com/how-dogs-find-their-way-home-without-a-gps-58526">magnetoreception</a>” just like <a href="https://theconversation.com/migrating-birds-use-a-magnetic-map-to-travel-long-distances-82624">migrating birds</a> and <a href="https://theconversation.com/revealed-bats-use-sunsets-to-reset-their-magnetic-compasses-and-fly-in-the-dark-29598">bats</a>. The recent study suggests that the whales’ detour into the North Sea was the result of a <a href="https://theconversation.com/our-predictions-of-solar-storms-have-not-been-very-accurate-until-now-heres-why-42669">geomagnetic storm</a> interfering with the whales’ magnetic navigation system. </p>
<p>The authors propose that these storms, which are the result of <a href="https://theconversation.com/prepare-yourself-wild-solar-weather-ahead-31560">explosions of particles from the sun</a>, created disturbances in the Earth’s magnetic field. They specifically identify two geomagnetic storms – occurring on December 20/21, 2015, and December 31 and January 1, 2015/2016 – which they argue could have caused disturbances strong enough to confuse the whales into travelling down the east coast of Shetland, rather than the west. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/184726/original/file-20170905-13755-ledk9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/184726/original/file-20170905-13755-ledk9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=659&fit=crop&dpr=1 600w, https://images.theconversation.com/files/184726/original/file-20170905-13755-ledk9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=659&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/184726/original/file-20170905-13755-ledk9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=659&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/184726/original/file-20170905-13755-ledk9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=828&fit=crop&dpr=1 754w, https://images.theconversation.com/files/184726/original/file-20170905-13755-ledk9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=828&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/184726/original/file-20170905-13755-ledk9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=828&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The magnetic map of where the Norwegian and North Seas join. The whales should have travelled along the white arrow, but instead travelled along the red arrow.</span>
<span class="attribution"><span class="source">Vanselow et al. (2017)</span></span>
</figcaption>
</figure>
<p>They suggest that a series of magnetic mountains, which have a magnetic field that is stronger than the surrounding area, would normally act as a barrier to the whales – preventing them from straying into the North Sea. During the storms, however, the local magnetic field was altered so much that these magnetic mountains appeared invisible to the whales – allowing them to pass into the North Sea. </p>
<h2>Powerful impact</h2>
<p>The idea that geomagnetic storms cause navigational issues for animals is somewhat new but previous studies have shown that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3128737/">homing pigeons</a> and <a href="http://jeb.biologists.org/content/130/1/63">migrating birds</a>, for example, have trouble navigating through regions of magnetic anomalies. One study has found that the number of honey bees returning to their hive seems to <a href="https://www.omicsonline.org/open-access/severe-honey-bee-apis-mellifera-losses-correlate-with-geomagnetic-andproton-disturbances-in-earths-atmosphere-2332-2519-1000134.php?aid=57103">drop significantly</a> during geomagnetic storms, though the exact link remains unknown.</p>
<p>We have known for a long time that the sun’s activity, and the <a href="https://theconversation.com/its-never-been-more-important-to-keep-an-eye-on-space-weather-65648">space weather</a> it produces, can have a significant impact on us here on Earth. Not only does space weather produce the <a href="https://theconversation.com/what-caused-those-spectacular-northern-lights-and-how-you-can-catch-them-next-time-39081">beautiful aurora</a> that lights up the night sky, it can also cause <a href="https://theconversation.com/how-space-weather-poses-a-risk-to-the-finance-industry-64621">serious damage to our technical systems</a>.</p>
<p>In fact, space weather has already resulted in damage to satellites, interference with the Global Positioning System (GPS) and power grid failure. And it is estimated that a <a href="https://theconversation.com/why-were-preparing-weather-forecasts-in-space-32638">serious space weather event</a> could cost the global economy <a href="https://www.bas.ac.uk/media-post/news-study-reveals-potential-cost-of-solar-storms/">US$40 billion per day</a>. </p>
<h2>Finding proof</h2>
<p>While there’s increasing evidence that space weather can also affect biological organisms, it’s important to remember that a correlation is not the same as proof.</p>
<p>Further scientific analyses, such as actually monitoring a large number of whales to see if, and how, their travel paths change during geomagnetic storms, will be needed to prove this link for sure. After all, geomagnetic storms happen fairly often, so it could simply be a coincidence that these two events happened around the same time.</p>
<p>While space weather scientists are working hard to prepare our technological systems for future space weather events, it seems as though we may have to let nature take its course for the whales – at least for now.</p><img src="https://counter.theconversation.com/content/83520/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nathan Case receives funding from the Science and Technology Facilities Council. This article does not reflect the views of the UK research councils. Nathan is a member of the AuroraWatch UK team at Lancaster University which issues alerts of potential aurora visibility from the UK.</span></em></p>Space weather can impact life on Earth.Nathan Case, Senior Research Associate in Space and Planetary Physics, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/785832017-06-01T09:19:17Z2017-06-01T09:19:17ZMission to the sun will protect us from devastating solar storms and help us travel deeper into space<figure><img src="https://images.theconversation.com/files/171774/original/file-20170601-1275-kzza19.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Magnificent coronal mass ejection at the sun in 2012.</span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>From prayer and sacrifice to sunbathing, humans have worshipped the sun since time immemorial. And it’s no wonder. At around 150m km away, it is close enough to provide the light, heat and energy to sustain the entire human race. But despite the fact that our parent star has been studied extensively with modern telescopes – both from home and in space – there’s a lot we don’t know about it.</p>
<p>This is why NASA is launching a revolutionary probe, set to lift-off on 11 August 2018, that will literally touch it. Initially dubbed the Solar Probe Plus mission, the spacecraft <a href="https://www.nasa.gov/feature/goddard/2017/nasa-renames-solar-probe-mission-to-honor-pioneering-physicist-eugene-parker">has now been renamed</a> the Parker Solar Probe. This is to honour physicist Eugene Parker who carried out important work on the solar wind – a stream of charged particles from the sun.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/171773/original/file-20170601-25673-mifjim.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171773/original/file-20170601-25673-mifjim.gif?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/171773/original/file-20170601-25673-mifjim.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=856&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171773/original/file-20170601-25673-mifjim.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=856&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171773/original/file-20170601-25673-mifjim.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=856&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171773/original/file-20170601-25673-mifjim.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1076&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171773/original/file-20170601-25673-mifjim.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1076&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171773/original/file-20170601-25673-mifjim.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1076&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Helios 2 mission.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<p>There have been many missions to investigate the sun. In 1976, the <a href="https://imagine.gsfc.nasa.gov/science/toolbox/missions/helios2.html">Helios 2</a> spacecraft came as close as 43m km from the sun’s atmosphere. But the $1.5 billion Parker probe will travel to just 6m km above the solar surface – some nine times closer than any spacecraft has ever gone before. This will open a new era of understanding as, for the first time, sensors will be able to detect and analyse phenomena as they occur in the sun. </p>
<p>While the cruising altitude of the mission may sound like a safe distance at millions of kilometres, the sun’s immense energy will relentlessly bombard the payload with heat. An 11.5cm thick carbon composite shroud, similar to what modern Formula 1 race cars employ in their high-performance braking systems, will shield the sensitive equipment. This will be crucial as temperatures will soar beyond 1,400°C.</p>
<p>At these extreme temperatures, the solar arrays that power the spacecraft will retract. This manoeuvre will allow the instruments and power sources to remain close to room temperature in the shadow of the carbon composite shield. Just as well, as the spacecraft will experience radiation 475 times more intense than Earth orbit. </p>
<p>Any errors in the planned spacecraft trajectories could result in the probe sinking deeper into the sun’s atmosphere, which is several million degrees hot. This could ultimately destroy the spacecraft. </p>
<h2>Solar science</h2>
<p>So what can we learn from this risky mission? The dynamic activity brought about by supercharged particles and radiation being released from the sun – encountering the Earth as they pass through the inner solar system – is called <a href="https://theconversation.com/the-scorching-winds-on-the-surface-of-the-sun-and-how-were-forecasting-them-44098">space weather</a>. The consequences of space weather can be catastrophic, including the loss of satellite communications, changes to the orbits of spacecraft around Earth and damaging surges throughout global power grids. Most important is the risk to astronauts exposed to the powerful ionising radiation. </p>
<p>The <a href="https://theconversation.com/how-space-weather-poses-a-risk-to-the-finance-industry-64621">devastating cost</a> of such fierce electromagnetic storms has been estimated at $2 trillion, resulting in space weather being formally listed in the <a href="https://www.gov.uk/government/publications/national-risk-register-for-civil-emergencies-2015-edition">UK’s National Risk Registry</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/171706/original/file-20170531-25704-1876hgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171706/original/file-20170531-25704-1876hgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=528&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171706/original/file-20170531-25704-1876hgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=528&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171706/original/file-20170531-25704-1876hgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=528&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171706/original/file-20170531-25704-1876hgz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=663&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171706/original/file-20170531-25704-1876hgz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=663&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171706/original/file-20170531-25704-1876hgz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=663&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Parker probe.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<p>The new solar probe will revolutionise our understanding of what conditions are necessary in the sun’s atmosphere to generate severe bouts of space weather by making direct measurements of the magnetic fields, plasma densities and atmosphere temperatures for the first time. In a similar way to how an elastic band can snap following excessive stretching, it is believed that the continual twisting and churning of the magnetic field lines that permeate the solar atmosphere may give rise to particle acceleration and radiation bombardment. Once the magnetic fields break, we can experience severe space weather. </p>
<p>Unfortunately, we presently have no direct method of sampling the sun’s magnetic fields. Scientists are attempting to uncover new techniques that will allow the twists, strengths and directions of the sun’s powerful fields to be determined, but so far they can’t provide an accurate enough understanding. This is where the Parker probe will provide a new age of understanding, since it will be able to sample the sun’s powerful magnetic fields while there.</p>
<p>Round-the-clock observations and direct measurements of the atmospheric conditions responsible for increased levels of space weather are paramount in order to provide crucial warning of imminent solar threats. An instrument suite on-board the probe, the FIELDS suite, will provide such unprecedented information. Scientists can then feed this into intensive computer models, ultimately allowing space, aviation, power and telecommunication authorities to be alerted when potentially devastating space weather is imminent. </p>
<p>Of course, understanding the origins of space weather also has implications for other important areas of astrophysical research. It will allow space agencies to better protect astronauts during future manned missions to Mars, where the thinner Martian atmosphere offers little protection to incoming solar radiation. </p>
<p>Also, by being able to accurately model the effects of the streaming solar wind, future spacecraft will be able to effectively use <a href="https://theconversation.com/why-sailing-to-the-stars-has-suddenly-become-a-realistic-goal-57762">solar sails</a> to help them reach further into the depths of the solar system, perhaps eventually opening up the possibility of truly interstellar travel.</p><img src="https://counter.theconversation.com/content/78583/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Jess receives funding from the UK Science and Technology Facilities Council (STFC). </span></em></p>The Parker probe will go closer to the sun than any other spacecraft has dared go before – literally touching it.David Jess, Lecturer and STFC Ernest Rutherford Fellow, Queen's University BelfastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/766012017-04-24T13:18:35Z2017-04-24T13:18:35ZCitizen scientists discover new type of aurora<figure><img src="https://images.theconversation.com/files/166480/original/file-20170424-25594-14gpl50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The aurora Steve.</span> <span class="attribution"><a class="source" href="https://www.facebook.com/photo.php?fbid=10154330305806962&set=oa.1687595721257106&type=3&theater">Rémi Farvacque/Alberta Aurora Chasers (facebook)</a></span></figcaption></figure><p>A collaboration between aurora-hunting citizen scientists and a team of professional researchers has resulted in the discovery of a completely new type of aurora. The finding was made possible thanks to photos taken by aurora enthusiasts from across the globe which scientists could then compare with data from satellites.</p>
<p>The aurora, more commonly known as the <a href="https://theconversation.com/the-southern-lights-put-on-a-display-in-the-night-sky-28612">northern or southern lights</a>, form when electrically charged particles collide with the gases in our upper atmosphere. These charged particles, which have been accelerated into our atmosphere by the Earth’s magnetic field, transfer their energy to the atmospheric gases (such as nitrogen and oxygen). This extra energy is then released in the form of light which gives us the majestic aurora. </p>
<p>The aurora varies in strength depending on how active the sun is. Normally, an aurora is only visible near the magnetic poles but, when particularly active, it can be seen from <a href="https://theconversation.com/what-caused-those-spectacular-northern-lights-and-how-you-can-catch-them-next-time-39081">much further away</a>. </p>
<p>We generally see the aurora as a band about the poles (known as the auroral oval). This band is often green, with tinges of red or purple thrown into the mix. But sightings of this new phenomenon were different – straight away people noticed it didn’t look like the “normal” aurora.</p>
<p>When pictures first starting appearing on <a href="https://www.facebook.com/groups/AlbertaAuroraChasers/">social media</a>, the odd aurora was widely assumed to be what is known as a “<a href="http://news.spaceweather.com/protonarc/">proton arc</a>”, but scientists knew that <a href="https://www.facebook.com/musubk/posts/10100459063136322">this wasn’t right</a>. Proton arcs are caused by protons (positively charged particles which make up the atomic nucleus along with neutrons) colliding with neutral gases in the atmosphere. <a href="https://wiki.oulu.fi/display/SpaceWiki/Proton+aurora">Proton aurora</a> are not visible by eye and are broad and diffuse. This new type of aurora, however, was visible by eye and was a bright, structured band of purple in the night sky. They knew it had to be something else – but what?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/166469/original/file-20170424-27254-e1icsn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/166469/original/file-20170424-27254-e1icsn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/166469/original/file-20170424-27254-e1icsn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/166469/original/file-20170424-27254-e1icsn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/166469/original/file-20170424-27254-e1icsn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/166469/original/file-20170424-27254-e1icsn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/166469/original/file-20170424-27254-e1icsn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Meet Steve, the bright purple band reflected in the lake.</span>
<span class="attribution"><span class="source">Dave Markel Photography, ESA</span></span>
</figcaption>
</figure>
<p>The <a href="http://aurorasaurus.org/">Aurorasaurus</a> citizen science project issued a call to arms to collect sightings of this as-yet-unnamed aurora. <a href="http://blog.aurorasaurus.org/?p=449">Over 50 sightings</a> from countries including Canada, US, UK and New Zealand were reported during 2016 and 2017. Because this type of aurora didn’t yet have a name, the citizen scientists called it “Steve” (after the animated children’s film, <a href="http://www.dreamworksanimation.com/oth/">Over the Hedge</a>).</p>
<p>The <a href="http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm/When_Swarm_met_Steve">biggest breakthrough</a> in identifying “Steve” came when Eric Donovan, an associate professor of physics and astronomy at the University of Calgary in Canada, found an instance where a photo was taken of “Steve” at the same time as one of the European Space Agency’s <a href="http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm">Swarm satellites</a> passed above it. Donovan found that as the satellite flew straight though Steve, data from the electric field instrument showed very clear changes.</p>
<figure>
<iframe src="https://player.vimeo.com/video/166121341" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Steve appears as a purple band (left of video). ‘Normal’ aurora appears as green (right of video).</span></figcaption>
</figure>
<p>Speaking at a recent <a href="https://livestream.com/ESA/earthexplorer2017/videos/152430872">scientific conference</a>, Donovan said that “the temperature 300km above Earth’s surface jumped by 3000°C and the data revealed a 25km-wide ribbon of gas flowing westwards at about 6km per second compared to a speed of about ten metres per second either side of the ribbon.”</p>
<p>This result definitively proved that “Steve” is in fact a distinct feature from the normal aurora oval, as the ribbon was located south of the main aurora. It also showed that “Steve” is not a proton arc.</p>
<p>While we have now been able to measure “Steve”, we still aren’t sure what causes it. It seems that “Steve” is fairly common but it took the power of citizen science for it to really be noticed. Donovan says that research is still ongoing but that he thinks <a href="http://gizmodo.com/what-the-hell-is-this-beautiful-thing-1794528895">he is close to finding the cause</a>.</p>
<p>Discoveries of new types of aurora are rare and this one highlights the importance of citizen scientists. If it weren’t for the dedication of amateur aurora hunters, we may never have started studying this new phenomenon. So if you think you’ve spotted “Steve”, make sure you <a href="http://aurorasaurus.org">submit your sighting</a> to Aurorasaurus to help us learn more about this beautiful purple streak.</p><img src="https://counter.theconversation.com/content/76601/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nathan Case receives funding from the Science and Technology Facilities Council. This article does not reflect the views of the UK research councils. Nathan is a member of the AuroraWatch UK team at Lancaster University which issues alerts of potential aurora visibility from the UK.</span></em></p>Scientists still don’t know what caused the mysterious phenomenon ‘Steve’.Nathan Case, Senior Research Associate in Space and Planetary Physics, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/719102017-01-27T09:02:04Z2017-01-27T09:02:04ZWhy the Earth’s magnetic poles could be about to swap places – and how it would affect us<figure><img src="https://images.theconversation.com/files/154278/original/image-20170125-23851-8inepe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Earth's magnetic field is hugely important to our survival.</span> <span class="attribution"><span class="source">NASA Goddard Space Flight Centre/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The Earth’s <a href="https://theconversation.com/earths-magnetic-heartbeat-a-thinner-past-and-new-alien-worlds-59442">magnetic field</a> surrounds our planet like an invisible force field – protecting life from harmful solar radiation by deflecting charged particles away. Far from being constant, this field is continuously changing. Indeed, our planet’s history includes at least several hundred global magnetic reversals, where north and south magnetic poles swap places. So when’s the next one happening and how will it affect life on Earth? </p>
<p>During a reversal the magnetic field won’t be zero, but will assume a weaker and more complex form. It <a href="http://scrippsscholars.ucsd.edu/cconstable/content/earths-magnetic-field-reversing">may fall to</a> 10% of the present-day strength and have magnetic poles at the equator or even the simultaneous existence of multiple “north” and “south” magnetic poles. </p>
<p>Geomagnetic reversals occur a few times every million years on average. However, the interval between reversals is very irregular and can range up to tens of millions of years. </p>
<p>There can also be temporary and incomplete reversals, known as events and excursions, in which the magnetic poles move away from the geographic poles – perhaps even crossing the equator – before returning back to their original locations. The last full reversal, the Brunhes-Matuyama, occurred around 780,000 years ago. A temporary reversal, <a href="http://www.nature.com/nature/journal/v253/n5494/abs/253705a0.html">the Laschamp event</a>, occurred around 41,000 years ago. It lasted less than 1,000 years with the actual change of polarity lasting around 250 years. </p>
<h2>Power cut or mass extinction?</h2>
<p>The alteration in the magnetic field during a reversal will weaken its shielding effect, allowing heightened levels of radiation on and above the Earth’s surface. Were this to happen today, the increase in charged particles reaching the Earth would result in increased risks for satellites, aviation, and ground-based electrical infrastructure. Geomagnetic storms, driven by the interaction of anomalously large eruptions of solar energy with our magnetic field, give us a foretaste of what we can expect with a weakened magnetic shield.</p>
<p>In 2003, <a href="https://www.nasa.gov/topics/solarsystem/features/halloween_storms.html">the so-called Halloween storm</a> caused local electricity-grid blackouts in Sweden, required the rerouting of flights to avoid communication blackout and radiation risk, and disrupted satellites and communication systems. But this storm was minor in comparison with other storms of the recent past, such as the <a href="http://www.history.com/news/a-perfect-solar-superstorm-the-1859-carrington-event">1859 Carrington event</a>, which caused aurorae as far south as the Caribbean. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/154398/original/image-20170126-30413-1k0cpxu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/154398/original/image-20170126-30413-1k0cpxu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=278&fit=crop&dpr=1 600w, https://images.theconversation.com/files/154398/original/image-20170126-30413-1k0cpxu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=278&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/154398/original/image-20170126-30413-1k0cpxu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=278&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/154398/original/image-20170126-30413-1k0cpxu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=349&fit=crop&dpr=1 754w, https://images.theconversation.com/files/154398/original/image-20170126-30413-1k0cpxu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=349&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/154398/original/image-20170126-30413-1k0cpxu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=349&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Aurora borealis.</span>
<span class="attribution"><span class="source">Soerfm/wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The impact of a major storm on today’s electronic infrastructure is not fully known. Of course any time spent without electricity, heating, air conditioning, GPS or internet would have a major impact; widespread blackouts could result in economic disruption<a href="http://news.agu.org/press-release/extreme-space-weather-induced-electricity-blackouts-could-cost-u-s-more-than-40-billion-daily/?utm_source=CPRE&utm_medium=email&utm_campaign=press%20releases&utm_content=17-03%20space%20weather%20economic%20impacts"> measuring in tens of billions of dollars a day</a>. </p>
<p>In terms of life on Earth and the direct impact of a reversal on our species we cannot definitively predict what will happen as modern humans did not exist at the time of the last full reversal. Several studies have tried to <a href="http://adsabs.harvard.edu/abs/1985Natur.314..341R">link past reversals with mass extinctions</a> – suggesting some reversals and episodes of extended volcanism <a href="http://www.sciencedirect.com/science/article/pii/S0012821X07003640,%20http://www.nature.com/ngeo/journal/v5/n8/full/ngeo1521.html">could be driven by a common cause</a>. However, there is no evidence of any impending cataclysmic volcanism and so we would only likely have to contend with the electromagnetic impact if the field does reverse relatively soon. </p>
<p>We do know that many animal species have some form of <a href="https://theconversation.com/no-fishy-business-salmon-use-earths-magnetic-field-to-migrate-22835">magnetoreception that enables them to sense the Earth’s magnetic field</a>. They may use this to assist in long-distance navigation during migration. But it is unclear what impact a reversal might have on such species. What is clear is that early humans did manage to live through the Laschamp event and life itself has survived the hundreds of full reversals evidenced in the geologic record.</p>
<h2>Can we predict geomagnetic reversals?</h2>
<p>The simple fact that we are “overdue” for a full reversal and the fact that the Earth’s field is currently decreasing at a rate of 5% per century, <a href="http://www.nature.com/nature/journal/v452/n7184/full/452165a.html">has led to suggestions</a> that the field may reverse within the next 2,000 years. But pinning down an exact date – at least for now – will be difficult.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/154274/original/image-20170125-23872-mjgami.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/154274/original/image-20170125-23872-mjgami.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=328&fit=crop&dpr=1 600w, https://images.theconversation.com/files/154274/original/image-20170125-23872-mjgami.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=328&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/154274/original/image-20170125-23872-mjgami.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=328&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/154274/original/image-20170125-23872-mjgami.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=412&fit=crop&dpr=1 754w, https://images.theconversation.com/files/154274/original/image-20170125-23872-mjgami.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=412&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/154274/original/image-20170125-23872-mjgami.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=412&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Magnetic reversal.</span>
<span class="attribution"><span class="source">NASA.</span></span>
</figcaption>
</figure>
<p>The Earth’s magnetic field is generated within the liquid core of our planet, by the slow churning of molten iron. Like the atmosphere and oceans, the way in which it moves is governed by the laws of physics. We should therefore be able to predict the “weather of the core” by tracking this movement, just like we can predict real weather by looking at the atmosphere and ocean. A reversal can then be likened to a particular type of storm in the core, where the dynamics – and magnetic field – go haywire (at least for a short while), before settling down again. </p>
<p>The difficulties of predicting the weather beyond a few days are widely known, despite us living within and directly observing the atmosphere. Yet predicting the Earth’s core is a far more difficult prospect, principally because it is buried beneath 3,000km of rock such that our observations are scant and indirect. However, we are not completely blind: we know the major composition of the material inside the core and that it is liquid. A global network of ground-based observatories and orbiting satellites also measure how the magnetic field is changing, which gives us insight into how the liquid core is moving.</p>
<p>The recent discovery of a <a href="http://www.nature.com/ngeo/journal/v10/n1/full/ngeo2859.html">jet-stream</a> within the core highlights our evolving ingenuity and increasing ability to measure and infer the dynamics of the core. Coupled with numerical simulations and laboratory experiments to study the fluid dynamics of the planet’s interior, our understanding is developing at a rapid rate. The prospect of being able to forecast the Earth’s core is perhaps not too far out of reach.</p><img src="https://counter.theconversation.com/content/71910/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Phil Livermore receives funding from the Natural Environment Research Council.</span></em></p><p class="fine-print"><em><span>Jon Mound receives funding from the Natural Environment Research Council. </span></em></p>A geomagnetic reversal may have a severe impact on humans.Phil Livermore, Associate Professor of geophysics, University of LeedsJon Mound, Associate Professor of Geophysics, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/702292016-12-12T16:01:26Z2016-12-12T16:01:26ZHow we caught the first glimpse of weather on a faraway gas giant<figure><img src="https://images.theconversation.com/files/149458/original/image-20161209-31396-j8hy9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mysterious gas giant is about 1,000 light years away.</span> <span class="attribution"><span class="source">Mark Garlick/University of Warwick.</span>, <span class="license">Author provided</span></span></figcaption></figure><p>More than 3,000 exoplanets, which orbit stars other than our sun, <a href="https://theconversation.com/more-than-1-000-new-exoplanets-discovered-but-still-no-earth-twin-59274">are now known</a> to exist. But just knowing that a planet exists is one thing – what we’d really like to know is what the conditions on that planet are like. Does it have an atmosphere, and does that atmosphere have weather? </p>
<p>We expect gas giants to have strong winds and violent storms, <a href="https://theconversation.com/from-great-red-spot-to-orange-pimple-is-jupiters-superstorm-finally-blowing-over-49318">like the Great Red Spot on Jupiter</a>. But to date, observing these things on a giant planet in another solar system has been impossible. That’s because detecting a planet’s atmosphere is very hard. We need bright targets, and even then the light from the parent star overwhelms that from the planet.</p>
<p>To study weather on an exoplanet we need not just to see the atmosphere, but how it changes over time. This has only been done once before, in relation to the “super-Earth” planet <a href="http://www.space.com/32416-super-earth-55-cancri-e-super-hot-weather.html">55 Cancri e</a>. Now we have for the first time observed the weather on a gas giant planet outside our own solar system. The results <a href="http://nature.com/articles/doi:10.1038/s41550-016-0004">have been published</a> in Nature Astronomy. </p>
<p>To study weather patterns on an exoplanet we can look at the light it reflects. Light from the parent star heats the planet, but some of it is reflected, either by the planet’s surface or its atmosphere – especially if the exoplanet is cloudy. On top of this the planet emits its own light, getting brighter the hotter it is. By observing the planet as it orbits, we can see changes in the planet’s light and so create a map of the brightness of the planet’s surface. If we observe multiple orbits of the planet, we can see how that brightness changes each orbit, and so work out how the planet’s atmosphere changes over time.</p>
<h2>The weather on HAT-P-7b</h2>
<p>We used <a href="https://kepler.nasa.gov/">NASA’s Kepler satellite</a> to track such changes on <a href="http://www.space.com/19421-backward-alien-planet-orbit-discovery.html">HAT-P-7b</a>, an exoplanet about 16 times larger than Earth and more than 1,000 light-years away in the <a href="http://www.constellation-guide.com/constellation-list/cygnus-constellation/">constellation Cygnus</a>. The gas giant – similar to Jupiter, but bigger – orbits very close to its star. In particular we looked at cloud formations coming and going for four entire years, giving us the most detailed determination yet of weather on an exoplanet. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/149630/original/image-20161212-31385-123wdde.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149630/original/image-20161212-31385-123wdde.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=350&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149630/original/image-20161212-31385-123wdde.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=350&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149630/original/image-20161212-31385-123wdde.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=350&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149630/original/image-20161212-31385-123wdde.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=440&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149630/original/image-20161212-31385-123wdde.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=440&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149630/original/image-20161212-31385-123wdde.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=440&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artist’s conception of the Kepler space telescope observing planets transiting a distant star.</span>
<span class="attribution"><span class="source">NASA Ames/W Stenzel</span></span>
</figcaption>
</figure>
<p>HAT-P-7b is tidally locked: one side of the planet is always in daylight facing the star, with the other side facing the cold of space. This makes the day side much hotter than the night side. Strong temperature differences like this <a href="http://worldbuilding.stackexchange.com/questions/4850/how-would-winds-behave-on-a-tidally-locked-planet">typically cause powerful winds</a>, blowing around the planet in an equatorial jet. </p>
<p>Because the night side of the planet is colder, we expect clouds to form there but rapidly evaporate when they reach the hot day side. But that’s not the whole story. The strong winds can transport the clouds, moving a bank of them to the “morning” part on the day side, where they stay for a while before evaporating. Clouds reflect light, so they make this region of the planet absorb less energy from the sun and cool down. A cooler day-side means weaker winds, and so less clouds moving there. But with fewer clouds, the planet can absorb more energy, allowing the day side to heat up and the winds to transport clouds again – forming a weather cycle.</p>
<p>When the winds are strong, the planet is brightest where the clouds are, and we see mostly reflected light. When the clouds are gone and the winds are weak, they still transport heat, meaning the brightest point is on the opposite side and we see mostly light emitted from the planet. By tracking changes in the brightest point on the planet we were able to see the winds changing and so observe weather in an exoplanet’s atmosphere.</p>
<p>But these clouds are like nothing seen on Earth. When we talk about temperature on a planet like HAT-P-7b, hot means 2,100°C and cold about 1,300°C. What could form a cloud that only evaporates in the middle “morning side”, at 1,700°C – hot enough to melt iron? While we don’t know for sure what the clouds are made of, one plausible answer is <a href="http://www.minerals.net/mineral/corundum.aspx">corundum</a>. Corundum is a mineral better known as ruby or sapphire, so perhaps clouds of ruby are moving around this planet, appearing and disappearing in a stunning display – from a distance.</p>
<p>Finding more examples will be a goal of future satellite missions such as <a href="https://theconversation.com/how-hubbles-successor-will-give-us-a-glimpse-into-the-very-first-galaxies-45970">NASA’s James Webb space telescope</a> and <a href="http://sci.esa.int/plato/">ESA’s PLATO</a>. Our study helps tell these missions know what to look for, although we will certainly find the unexpected too. </p>
<p>Planets are diverse: we know of <a href="https://theconversation.com/more-than-1-000-new-exoplanets-discovered-but-still-no-earth-twin-59274">Earth-like planets, super-Earths, Neptunes and Jupiters</a>, many at temperatures far exceeding anything in the solar system, and in planetary systems unlike anything we’ve seen before. Exoplanet atmospheres will be just as diverse, and a whole range of atmospheres and weather are waiting to be uncovered. While we studied a hot giant planet here, the same techniques may one day be used to look at planets like the Earth. To find out if such a planet is habitable, we need to understand its atmosphere and better yet, its weather.</p><img src="https://counter.theconversation.com/content/70229/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Armstrong receives funding from the European Union Seventh Framework program (FP7/2007- 2013) under grant agreement No. 313014 (ETAEARTH).</span></em></p>Ruby and sapphire clouds may be hovering over exoplanet HAT-P-7b.David Armstrong, Researcher in Astrophysics, University of WarwickLicensed as Creative Commons – attribution, no derivatives.