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Huge satellite BlueWalker-3 has now unfurled – and yes it’s very bright

<p>If you look at the sky near Jupiter just after sunset, you might notice a bright new star, travelling fast across the sky.</p> <p>This star is no planet or far-flung galaxy – it’s the largest commercial communications satellite in low-Earth orbit, the BlueWalker 3 satellite which has now unfurled its solar panels.</p> <p>The apartment-sized satellite is a prototype from American company AST SpaceMobile, whose goal is to create a space-based mobile broadband network. This is only one of multiple satellites planned for the SpaceMobile constellation – some of which will be even bigger than BlueWalker 3.</p> <p>Amateur astronomers have been reporting sightings of BlueWalker 3 over the last few weeks, many with an approximate brightness of 2<sup>nd</sup> or 3<sup>rd</sup> magnitude. This is moderately bright, but not as bright as Sirius <a href="https://earthsky.org/astronomy-essentials/what-is-stellar-magnitude/" target="_blank" rel="noopener">– the brightest star in the night sky.</a></p> <figure class="wp-block-embed aligncenter is-type-rich is-provider-twitter wp-block-embed-twitter"> <div class="wp-block-embed__wrapper"> <div class="entry-content-asset"> <div class="embed-wrapper"> <div class="inner"> <div class="twitter-tweet twitter-tweet-rendered spai-bg-prepared" style="display: flex; max-width: 500px; width: 100%; margin-top: 10px; margin-bottom: 10px;"><iframe id="twitter-widget-0" class="spai-bg-prepared" style="display: block; position: static; visibility: visible; width: 400px; height: 550px; flex-grow: 1;" title="Twitter Tweet" src="https://platform.twitter.com/embed/Tweet.html?creatorScreenName=cosmosmagazine&dnt=true&embedId=twitter-widget-0&features=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&frame=false&hideCard=false&hideThread=false&id=1591249397953998849&lang=en&origin=https%3A%2F%2Fcosmosmagazine.com%2Fspace%2Fbluewalker-3-unfurlled-ast-space-x-elon-musk%2F&sessionId=96d02fb5de79caae06b83ca7b911f2ac94853601&siteScreenName=cosmosmagazine&theme=light&widgetsVersion=a3525f077c700%3A1667415560940&width=500px" frameborder="0" scrolling="no" allowfullscreen="allowfullscreen" data-tweet-id="1591249397953998849"></iframe></div> </div> </div> </div> </div> </figure> <p>This means that some astronomers prediction that it “could outshine all stars and planets in the night sky” hasn’t come to pass.</p> <p>However, <a href="https://en.wikipedia.org/wiki/List_of_brightest_stars" target="_blank" rel="noopener">a magnitude of 2 would put it in the rank of top 50</a> brightest stars.</p> <p>If you wanted to track it for yourself, <a href="https://heavens-above.com/" target="_blank" rel="noopener">website Heavens Above</a> has just created a new tool <a href="https://www.orbtrack.org/#/?satName=BLUEWALKER%203" target="_blank" rel="noreferrer noopener">to track the satellite.</a> <a href="https://in-the-sky.org/satpasses.php?gotosat=53807" target="_blank" rel="noreferrer noopener">You can also use In The Sky and note your location.</a> Note that it can only be seen just after the Sun has gone down, as the Sun from below the horizon reflects onto the satellite, and makes it bright.</p> <figure class="wp-block-embed aligncenter is-type-rich is-provider-twitter wp-block-embed-twitter"> <div class="wp-block-embed__wrapper"> <div class="entry-content-asset"> <div class="embed-wrapper"> <div class="inner"> <div class="twitter-tweet twitter-tweet-rendered spai-bg-prepared" style="display: flex; max-width: 500px; width: 100%; margin-top: 10px; margin-bottom: 10px;"><iframe id="twitter-widget-1" class="spai-bg-prepared" style="display: block; position: static; visibility: visible; width: 400px; height: 675px; flex-grow: 1;" title="Twitter Tweet" src="https://platform.twitter.com/embed/Tweet.html?creatorScreenName=cosmosmagazine&dnt=true&embedId=twitter-widget-1&features=eyJ0ZndfdGltZWxpbmVfbGlzdCI6eyJidWNrZXQiOlsibGlua3RyLmVlIiwidHIuZWUiLCJ0ZXJyYS5jb20uYnIiLCJ3d3cubGlua3RyLmVlIiwid3d3LnRyLmVlIiwid3d3LnRlcnJhLmNvbS5iciJdLCJ2ZXJzaW9uIjpudWxsfSwidGZ3X2hvcml6b25fdGltZWxpbmVfMTIwMzQiOnsiYnVja2V0IjoidHJlYXRtZW50IiwidmVyc2lvbiI6bnVsbH0sInRmd190d2VldF9lZGl0X2JhY2tlbmQiOnsiYnVja2V0Ijoib24iLCJ2ZXJzaW9uIjpudWxsfSwidGZ3X3JlZnNyY19zZXNzaW9uIjp7ImJ1Y2tldCI6Im9uIiwidmVyc2lvbiI6bnVsbH0sInRmd19jaGluX3BpbGxzXzE0NzQxIjp7ImJ1Y2tldCI6ImNvbG9yX2ljb25zIiwidmVyc2lvbiI6bnVsbH0sInRmd190d2VldF9yZXN1bHRfbWlncmF0aW9uXzEzOTc5Ijp7ImJ1Y2tldCI6InR3ZWV0X3Jlc3VsdCIsInZlcnNpb24iOm51bGx9LCJ0Zndfc2Vuc2l0aXZlX21lZGlhX2ludGVyc3RpdGlhbF8xMzk2MyI6eyJidWNrZXQiOiJpbnRlcnN0aXRpYWwiLCJ2ZXJzaW9uIjpudWxsfSwidGZ3X2V4cGVyaW1lbnRzX2Nvb2tpZV9leHBpcmF0aW9uIjp7ImJ1Y2tldCI6MTIwOTYwMCwidmVyc2lvbiI6bnVsbH0sInRmd19kdXBsaWNhdGVfc2NyaWJlc190b19zZXR0aW5ncyI6eyJidWNrZXQiOiJvbiIsInZlcnNpb24iOm51bGx9LCJ0ZndfdmlkZW9faGxzX2R5bmFtaWNfbWFuaWZlc3RzXzE1MDgyIjp7ImJ1Y2tldCI6InRydWVfYml0cmF0ZSIsInZlcnNpb24iOm51bGx9LCJ0Zndfc2hvd19ibHVlX3ZlcmlmaWVkX2JhZGdlIjp7ImJ1Y2tldCI6Im9uIiwidmVyc2lvbiI6bnVsbH0sInRmd190d2VldF9lZGl0X2Zyb250ZW5kIjp7ImJ1Y2tldCI6Im9uIiwidmVyc2lvbiI6bnVsbH19&frame=false&hideCard=false&hideThread=false&id=1594885656370909186&lang=en&origin=https%3A%2F%2Fcosmosmagazine.com%2Fspace%2Fbluewalker-3-unfurlled-ast-space-x-elon-musk%2F&sessionId=96d02fb5de79caae06b83ca7b911f2ac94853601&siteScreenName=cosmosmagazine&theme=light&widgetsVersion=a3525f077c700%3A1667415560940&width=500px" frameborder="0" scrolling="no" allowfullscreen="allowfullscreen" data-tweet-id="1594885656370909186"></iframe></div> </div> </div> </div> </div> </figure> <p>The goal with AST SpaceMobile is to create cellular broadband anywhere on the globe. Similar to Space X’s Starlink, many satellites are required to create full coverage around the world.</p> <p>Astronomers and satellite operators are currently at odds over these satellite constellations. The more there, the more interference is likely for both optical and radio astronomy.</p> <p>There’s also the question of what we – as humans – are comfortable with. Having 100s of these satellites in the sky at any one time would mean that when we look up, many of the bright lights in the sky would not be stars but satellites instead.</p> <figure class="wp-block-embed aligncenter is-type-rich is-provider-twitter wp-block-embed-twitter"> <div class="wp-block-embed__wrapper"> <div class="entry-content-asset"> <div class="embed-wrapper"> <div class="inner"> <div class="twitter-tweet twitter-tweet-rendered spai-bg-prepared" style="display: flex; max-width: 500px; width: 100%; margin-top: 10px; margin-bottom: 10px;"><iframe id="twitter-widget-2" class="spai-bg-prepared" style="display: block; position: static; visibility: visible; width: 400px; height: 699px; flex-grow: 1;" title="Twitter Tweet" src="https://platform.twitter.com/embed/Tweet.html?creatorScreenName=cosmosmagazine&dnt=true&embedId=twitter-widget-2&features=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&frame=false&hideCard=false&hideThread=false&id=1595568298414215168&lang=en&origin=https%3A%2F%2Fcosmosmagazine.com%2Fspace%2Fbluewalker-3-unfurlled-ast-space-x-elon-musk%2F&sessionId=96d02fb5de79caae06b83ca7b911f2ac94853601&siteScreenName=cosmosmagazine&theme=light&widgetsVersion=a3525f077c700%3A1667415560940&width=500px" frameborder="0" scrolling="no" allowfullscreen="allowfullscreen" data-tweet-id="1595568298414215168"></iframe></div> </div> </div> </div> </div> </figure> <p>There’s also potentially issues about collisions in orbit <a href="https://arstechnica.com/science/2020/11/nasa-objects-to-new-megaconstellation-citing-risk-of-catastrophic-collison/" target="_blank" rel="noopener">making our skies unsafe.</a></p> <p>There’s currently discussions happening between astronomers, satellite operators and the United Nations Committee on Peaceful Uses of Outer Space (COPUOS) about what is reasonable for satellites to be able to do in the night sky. The next meeting <a href="https://www.skatelescope.org/news/un-body-to-continue-deliberating-on-how-to-protect-dark-quiet-skies/" target="_blank" rel="noopener">will occur in 2023</a>.</p> <p>“States are generally supportive, and we succeeded in ensuring that the radio and optical interference effects of large satellite constellations on astronomy are considered by the subcommittee,” Head of Assurance at the SKAO, Tim Stevenson said after the last meeting in February.</p> <p>“We are looking forward to preparing and sustaining our case in COPUOS, which is the paramount forum in the world to deal with this issue.”</p> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=226135&title=Huge+satellite+BlueWalker-3+has+now+unfurled+%E2%80%93+and+yes+it%E2%80%99s+very+bright" width="1" height="1" data-spai-target="src" data-spai-orig="" data-spai-exclude="nocdn" /></p> <div id="contributors"> <p><em><a href="https://cosmosmagazine.com/space/bluewalker-3-unfurlled-ast-space-x-elon-musk/" target="_blank" rel="noopener">This article</a> was originally published on Cosmos Magazine and was written by Jacinta Bowler. </em></p> <p><em>Image: AST</em></p> </div>

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How satellites, radar and drones are tracking meteorites and aiding Earth’s asteroid defence

<p>On July 31 2013 a <a href="https://cneos.jpl.nasa.gov/fireballs/" target="_blank" rel="noopener">constellation of US defence satellites</a> saw a streak of light over South Australia as a rock from outer space burned through Earth’s atmosphere on its way to crash into the ground below.</p> <p>The impact created an explosion equivalent to about 220 tonnes of TNT. More than 1,500km away, in Tasmania, the bang was heard by detectors normally used to listen for <a href="https://www.dfat.gov.au/international-relations/security/asno/Pages/australian-ims-stations" target="_blank" rel="noopener">extremely low-frequency sounds</a> from illegal tests of nuclear weapons.</p> <p>These were two excellent indications that there should be a patch of ground covered in meteorites somewhere north of Port Augusta. But how could we track them down?</p> <p>My colleagues and I who work on the <a href="https://dfn.gfo.rocks/" target="_blank" rel="noopener">Desert Fireball Network (DFN)</a>, which tracks incoming asteroids and <a href="https://dfn.gfo.rocks/meteorites.html" target="_blank" rel="noopener">the resulting meteorites</a>, had a couple of ideas: weather radar and drones.</p> <p><strong>Eyes in space</strong></p> <p>Finding meteorites is not an easy task. There is a network of high-quality ground-based sensors called the <a href="https://gfo.rocks/" target="_blank" rel="noopener">Global Fireball Observatory</a>, but it only covers about 1% of the planet.</p> <p>The <a href="https://cneos.jpl.nasa.gov/fireballs/" target="_blank" rel="noopener">US satellite data</a> published by NASA covers a much larger area than ground-based detectors, but it only picks up the biggest fireballs. What’s more, they <a href="https://academic.oup.com/mnras/article/483/4/5166/5256650" target="_blank" rel="noopener">don’t always give an accurate idea of the meteor’s trajectory</a>.</p> <p>So, to have any chance to find a meteorite from these data, you need a little outside help.</p> <p><strong>Weather radars</strong></p> <p>In 2019, Australia’s Bureau of Meteorology started making its weather radar data <a href="https://www.openradar.io/" target="_blank" rel="noopener">openly available</a> to researchers and the public. I saw this as an opportunity to complete the puzzle.</p> <p>I combed through the record of events from the Desert Fireball Network and NASA, and cross-matched them with nearby weather radars. Then I looked for unusual radar signatures that could indicate the presence of falling meteorites.</p> <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/496384/original/file-20221121-22-iwtkve.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/496384/original/file-20221121-22-iwtkve.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/496384/original/file-20221121-22-iwtkve.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=334&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/496384/original/file-20221121-22-iwtkve.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=334&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/496384/original/file-20221121-22-iwtkve.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=334&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/496384/original/file-20221121-22-iwtkve.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=420&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/496384/original/file-20221121-22-iwtkve.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=420&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/496384/original/file-20221121-22-iwtkve.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=420&amp;fit=crop&amp;dpr=3 2262w" alt="An annoyed aerial photo showing the locations of the Woomera radar station and the falling meteorites." /></a><figcaption><span class="caption">The Woomera weather radar station captured reflections from the falling meteorites.</span> <span class="attribution"><span class="source">Curtin University</span>, <span class="license">Author provided</span></span></figcaption></figure> <p>And bingo, the 2013 event was not too far from the Woomera radar station. The weather was clear, and the radar record showed some small reflections at about the right place and time.</p> <p>Next, I had to use the weather data to figure out how the wind would have pushed the meteorites around on their way down to Earth.</p> <p>If I got the calculations right, I would have a treasure map showing the location of a rich haul of meteorites. If I got them wrong, I would end up sending my team to wander around in the desert for two weeks for nothing.</p> <p><strong>The search</strong></p> <p>I gave what I hoped was an accurate treasure map to my colleague Andy Tomkins from Monash University. In September this year, he happened to be driving past the site on his way back from an expedition in the Nullarbor.</p> <p>Thankfully, Andy found the first meteorite within 10 minutes of looking. In the following two hours, his team found nine more.</p> <figure class="align-center "><img src="https://images.theconversation.com/files/496385/original/file-20221121-16-he3p7h.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/496385/original/file-20221121-16-he3p7h.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/496385/original/file-20221121-16-he3p7h.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/496385/original/file-20221121-16-he3p7h.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/496385/original/file-20221121-16-he3p7h.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/496385/original/file-20221121-16-he3p7h.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/496385/original/file-20221121-16-he3p7h.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" alt="Photo of several people walking through a desert field looking at the ground." /><figcaption><span class="caption">A field team from Monash University searched for meteorites in the strewn field.</span> <span class="attribution"><span class="source">Monash University</span>, <span class="license">Author provided</span></span></figcaption></figure> <p>The technique of finding meteorites with weather radars <a href="https://ares.jsc.nasa.gov/meteorite-falls/how-to-find-meteorites/" target="_blank" rel="noopener">was pioneered</a> by my colleague Marc Fries in the US. However, this is the first time it has been done outside the US NEXRAD radar network. (When it comes to monitoring airspace, the US has more powerful and more densely packed tech than anyone else.)</p> <p>This first search confirmed there were lots of meteorites on the ground. But how were we going to find them all?</p> <p>That’s where the drones come in. We used a method developed by my colleague Seamus Anderson to <a href="https://gfo.rocks/blog/2022/03/14/First_Meteorite_Found_with_Drone.html" target="_blank" rel="noopener">automatically detect meteorites from drone images</a>.</p> <p>In the end we collected 44 meteorites, weighing a bit over 4kg in total. Together they form what we call a “strewn field”.</p> <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/496386/original/file-20221121-13-qssltc.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/496386/original/file-20221121-13-qssltc.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/496386/original/file-20221121-13-qssltc.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/496386/original/file-20221121-13-qssltc.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/496386/original/file-20221121-13-qssltc.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/496386/original/file-20221121-13-qssltc.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/496386/original/file-20221121-13-qssltc.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/496386/original/file-20221121-13-qssltc.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" alt="An aerial view of a desert field with a black dot (a meteorite) highlighted by a yellow square." /></a><figcaption><span class="caption">A machine-learning algorithm identified meteorites from drone photos.</span> <span class="attribution"><span class="source">Curtin Uni</span>, <span class="license">Author provided</span></span></figcaption></figure> <p>Strewn fields <a href="https://onlinelibrary.wiley.com/doi/10.1111/maps.13892" target="_blank" rel="noopener">tell us a lot</a> about how an asteroid fragments in our atmosphere.</p> <p>That’s quite important to know, because the energy of these things is comparable to that of nuclear weapons. For example, the 17-metre asteroid that exploded over Chelyabinsk in Russia in 2013 produced an explosion 30 times the size of the bomb dropped on Hiroshima in 1945.</p> <p>So when the next big one is about to hit, it may be useful to predict how it will deposit its energy in our atmosphere.</p> <p>With new telescopes and better technology, we are starting to see some asteroids <a href="https://skymapper.anu.edu.au/news/great-balls-fire/" target="_blank" rel="noopener">before they hit Earth</a>. We will see even more when projects such as the <a href="https://www.lsst.org" target="_blank" rel="noopener">Vera Rubin Observatory</a> and the <a href="https://atlas.fallingstar.com" target="_blank" rel="noopener">Asteroid Terrestrial-impact Last Alert System (ATLAS)</a> are up and running.</p> <p>These systems might give us as much as a few days’ notice that an asteroid is heading for Earth. This would be too late to make any effort to deflect it – but plenty of time for preparation and damage control on the ground.</p> <p><strong>The value of open data</strong></p> <p>This find was only made possible by the free availability of crucial data – and the people who made it available.</p> <p>The US satellites that detected the fireball are presumably there to detect missile and rocket launches. However, somebody (I don’t know who) must have figured out how to publish some of the satellite data without giving away too much about their capabilities, and then lobbied hard to get the data released.</p> <p>Likewise, the find would not have happened without the work of Joshua Soderholm at Australia’s Bureau of Meteorology, who worked to make low-level weather radar data openly accessible for other uses. Soderholm went to the trouble to make the radar data <a href="https://www.go-fair.org/fair-principles/" target="_blank" rel="noopener">readily available and easy to use</a>, which goes well beyond the vague formulations you can read at the bottom of scientific papers like “data available upon reasonable request”.</p> <p>There is no shortage of fireballs to track down. Right now, we’re on the hunt for a meteorite that was spotted in space last weekend before <a href="https://www.nytimes.com/2022/11/19/science/fireball-asteroid-toronto-new-york.html" target="_blank" rel="noopener">blazing through the sky over Ontario, Canada</a>.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/194997/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /></p> <p><em>Writen by Hadrien Devillepoix. Republished with permission from <a href="https://theconversation.com/how-satellites-radar-and-drones-are-tracking-meteorites-and-aiding-earths-asteroid-defence-194997" target="_blank" rel="noopener">The Conversation</a>.</em></p> <p><em>Image: NASA</em></p>

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Webb on Webb: How JWST peers back in time at the earliest stages of the Universe

<p>What did the first galaxies and <a href="https://cosmosmagazine.com/science/physics/webb-spotted-first-oldest-stars/" target="_blank" rel="noreferrer noopener">stars look like</a>? How have they evolved over time? Does life exist somewhere else out there in the great inky blackness of the universe? How can astronomers possibly hope to see through the vast amounts of gas and dust to uncover nascent stars nestled in their cloudy nurseries?</p> <p>In <em>Cosmos Magazine #96</em>, Swinburne University postdoctoral researcher, Sarah Webb, explains how astronomers are exploring these questions, uncovering the deepest mysteries of the universe and space and time.</p> <p>The appropriately named Webb, walks us through the most powerful time machine we’ve ever built, showing us how the <a href="https://www.nasa.gov/image-feature/james-webb-space-telescopes-golden-mirror/" target="_blank" rel="noreferrer noopener">golden mirrors</a> of the James Webb Space Telescope (JWST) allow it to peer through the space dense with gas and dust and look at (but not touch!) the very early days of our universe.</p> <div class="newsletter-box"> <div id="wpcf7-f6-p217307-o1" class="wpcf7" dir="ltr" lang="en-US" role="form"> </div> </div> <p>Be dazzled by beautiful, swirling galaxies and cliffs of dust hiding bright new-born stars as Webb explains the science behind her favourite JWST images, including the Southern Ring Nebula, spiral galaxy NGC 628 and the Cartwheel galaxy.</p> <p>Comparing the Hubble Deep Field with the JWST First Deep Field, we can see just how far technology, engineering and science have come, with JWST seeing further and more clearly than any instrument before it.</p> <p>Australia’s research contribution is highlighted, as Webb discusses some of the incredible science being done by astronomers right here in Australia – work which demonstrates JWST’s unbelievable potential to contribute to an enormous number of fields such as finding the most distant galaxy, early galaxy birth and evolution, dead stars, planets and asteroids, and of course looking for the most promising exoplanetary candidates for signs of life elsewhere in the Universe.</p> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=217307&amp;title=Webb+on+Webb%3A+How+JWST+peers+back+in+time+at+the+earliest+stages+of+the+Universe" width="1" height="1" /></p> <div id="contributors"> <p><em><a href="https://cosmosmagazine.com/science/webb-on-webb-back-time-early-universe/" target="_blank" rel="noopener">This article</a> was originally published on <a href="https://cosmosmagazine.com" target="_blank" rel="noopener">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/clare-kenyon" target="_blank" rel="noopener">Clare Kenyon</a>. Clare Kenyon is a science journalist for Cosmos. An ex-high school teacher, she is currently wrangling the death throes of her PhD in astrophysics, has a Masters in astronomy and another in education. Clare also has diplomas in music and criminology and a graduate certificate of leadership and learning.</em></p> <p><em>Image: </em><em>NASA, ESA, CSA, and STScI</em></p> </div>

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The largest commercial communications array ever has just launched. Expect to see it – it’s huge and bright

<p>On the weekend SpaceX’s Falcon 9 rocket launched a giant satellite into space.</p> <p>Called BlueWalker 3, it’s a prototype by American company <a href="https://finance.yahoo.com/news/ast-spacemobile-announces-bluewalker-3-123100434.html" target="_blank" rel="noopener">AST SpaceMobile</a>, which is to create a space-based mobile broadband network. This is only one of multiple satellites planned for the SpaceMobile constellation – <a href="https://space.skyrocket.de/doc_sdat/bluewalker-3.htm" target="_blank" rel="noopener">some even bigger than BlueWalker 3.</a></p> <p>“The reason why our satellite is large is because in order to communicate with a low-power, low internal strength phone, you just need a large antenna on one side with a lot of power, and so that’s a critical part of our infrastructure,” <a href="https://www.space.com/spacex-bluewalker-3-starlink-satellites-launch-success" target="_blank" rel="noopener">AST SpaceMobile Chief Strategy Officer Scott Wisniewski told Space.com.</a></p> <p>“We think that’s really important for communicating directly with regular handsets, with no change to the handset, with no extra burdens on the user.”</p> <p>Although this is potentially exciting for those who need that connectivity, astronomers are concerned about just how big and bright this satellite will be.</p> <p><a href="https://www.newscientist.com/article/2337336-huge-satellite-could-outshine-all-stars-and-planets-in-the-night-sky/" target="_blank" rel="noopener">A New Scientist report</a> has even suggested that the satellite “could outshine all stars and planets in the night sky”.</p> <p>This is because the satellite is huge and reflective. Once the satellite unfurls – which it will do in the next few weeks – the antenna will measure 64m<sup>2</sup>.</p> <div class="newsletter-box"> <div id="wpcf7-f6-p213406-o1" class="wpcf7" dir="ltr" lang="en-US" role="form"> </div> </div> <p>As <a href="https://www.universetoday.com/157410/bluewalker-3-satellite-launches-this-weekend-may-be-bright/" target="_blank" rel="noopener">Universe Today notes</a> that’s in the same ballpark as NASA’s Echo-1 sphere launched in 1960. <a href="https://en.wikipedia.org/wiki/Project_Echo" target="_blank" rel="noopener">That ‘satelloon’ as</a> it was called, was also reflective, and was easy visible to the naked eye over most of Earth.</p> <p>With plans for a number of these huge satellites, ground based optical telescopes may struggle to image the night sky without disturbance.</p> <p>This is a continuation of worries from a few years ago, <a href="https://cosmosmagazine.com/space/spacex-astronomers-warn-over-musks-planned-satellite-constellation/">where SpaceX’s own satellite megaconstellation Starlink</a> began to affect astronomers’ work.</p> <p>The Falcon 9 rocket also included new Starlink satellites<a href="https://spaceflightnow.com/2022/05/13/spacex-passes-2500-satellites-launched-for-companys-starlink-network/" target="_blank" rel="noopener">, which brings the numbers over 2,200 active satellites</a> – which is about half the number of satellites SpaceX wants in orbit. It’s also worth pointing out that around <a href="https://dewesoft.com/daq/every-satellite-orbiting-earth-and-who-owns-them" target="_blank" rel="noopener">half of the satellites currently in orbit are Starlink’s. </a> </p> <p><a href="https://www.science.org/content/article/starlink-already-threatens-optical-astronomy-now-radio-astronomers-are-worried" target="_blank" rel="noopener">Radio astronomers</a> are also nervous. As <a href="https://www.sciencealert.com/starlink-is-being-an-absolute-nuisance-to-astronomers" target="_blank" rel="noopener">Alan Duffy at the time told ScienceAlert</a> “a full constellation of Starlink satellites will likely mean the end of Earth-based microwave-radio telescopes able to scan the heavens for faint radio objects.”</p> <p>Currently, astronomers are building a group to tackle this problem called the ‘IAU Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference’. It’s quite a mouthful, but the problem requires not only technological fixes, but tough conversations with these technology companies to come to a solution for everyone.</p> <p>Luckily, Jeffrey Hall, director of Lowell Observatory in Arizona, US, <a href="https://cosmosmagazine.com/space/increasing-concerns-about-crowded-space/">told Cosmos back in 2020,</a> “neither astronomers nor space scientists are strangers to difficult problems.”</p> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=213406&amp;title=The+largest+commercial+communications+array+ever+has+just+launched.+Expect+to+see+it+%26%238211%3B+it%E2%80%99s+huge+and+bright" width="1" height="1" /></p> <div id="contributors"> <p><em><a href="https://cosmosmagazine.com/technology/bluewalker-launched-spacex-largest-satellite-astronomers/" target="_blank" rel="noopener">This article</a> was originally published on <a href="https://cosmosmagazine.com" target="_blank" rel="noopener">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/jacinta-bowler" target="_blank" rel="noopener">Jacinta Bowler</a>. Jacinta Bowler is a science journalist at Cosmos. They have a undergraduate degree in genetics and journalism from the University of Queensland and have been published in the Best Australian Science Writing 2022.</em></p> <p><em>Image: Getty Images</em></p> </div>

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Spinetingling audio of a black hole goes viral, here’s why

<p dir="ltr">Audio that allows us to “hear a black hole” has gone viral online since it was shared by NASA, with listeners describing it as “creepy” and “ethereally beautiful”.</p> <p dir="ltr">NASA first shared the audio taken from the black hole in the Perseus galaxy cluster in May, which it described as a remixed sonification of sound waves discovered in 2003, but a recent re-posting on Twitter has seen it gone viral.</p> <p><span id="docs-internal-guid-f388abe3-7fff-2cd0-68cf-89aaead1f146"></span></p> <p dir="ltr">Here’s how it sounds:</p> <blockquote class="twitter-tweet"> <p dir="ltr" lang="en">The misconception that there is no sound in space originates because most space is a ~vacuum, providing no way for sound waves to travel. A galaxy cluster has so much gas that we've picked up actual sound. Here it's amplified, and mixed with other data, to hear a black hole! <a href="https://t.co/RobcZs7F9e">pic.twitter.com/RobcZs7F9e</a></p> <p>— NASA Exoplanets (@NASAExoplanets) <a href="https://twitter.com/NASAExoplanets/status/1561442514078314496?ref_src=twsrc%5Etfw">August 21, 2022</a></p></blockquote> <p dir="ltr">Nearly twenty years ago, researchers at the Chandra X-Ray Observatory “discovered that pressure waves sent out by the black hole caused ripples in the cluster’s hot gas that could be translated into a note”.</p> <p dir="ltr">But, said note was too low for humans to hear, being the equivalent of a B-flat 57 octaves below the middle C note on a piano, according to NASA.</p> <p dir="ltr">To create something we could actually hear, scientists used a process called sonification, which is where astronomical data is translated into sound.</p> <p dir="ltr">According to NASA, the  creepy sound was created using sound waves extracted outwards from the centre of the Perseus cluster, with astronomers increasing the frequency by 57 and 58 octaves.</p> <p dir="ltr">A radar-like scan around the image was also used to help us hear sound waves emitted in different directions.</p> <p dir="ltr"><span id="docs-internal-guid-b422c896-7fff-4c03-4c1f-0b305a6f28e2"></span></p> <p dir="ltr">“Another way to put this is that they are being heard 144 quadrillion and 288 quadrillion times higher than their original frequency,” NASA said.</p> <blockquote class="twitter-tweet"> <p dir="ltr" lang="en">I was today years old when I found out that sound could travel into space.<br />In fact, NASA released sound waves received from a black hole!<br />Creepy 😲<br />Next, music please? 🎶<a href="https://t.co/myk0laXDV4">pic.twitter.com/myk0laXDV4</a></p> <p>— Elie Habib (@elie_h) <a href="https://twitter.com/elie_h/status/1561773483092320256?ref_src=twsrc%5Etfw">August 22, 2022</a></p></blockquote> <p dir="ltr">James Miller-Jones, a Professor of Astrophysics at Curtin University, told the <em><a href="https://www.abc.net.au/news/2022-08-24/nasa-audio-black-hole-sounds-viral-hear-space/101360094" target="_blank" rel="noopener">ABC</a></em> that the frequencies of these sound waves are impacted by gases in the Perseus cluster.</p> <p dir="ltr">"Those sound waves are bumping into regions of dense gas, hotter gas, cooler gas, so they'll move in slightly different speeds in different directions," he explained.</p> <p dir="ltr">"That means they don't have a perfect circular shape. So as they scan around the cluster … it's capturing slightly different pitches."</p> <p dir="ltr">While this isn’t the first time the space agency has <a href="https://www.oversixty.com.au/entertainment/technology/hear-recordings-of-space-from-nasa-s-spacecraft" target="_blank" rel="noopener">shared sounds from space</a>, these sounds of the Perseus cluster differ in that they also use sound waves.</p> <p dir="ltr">"This is the only one that I've seen that is really translating real sound waves into the sonification, and to me that's just a beautiful demonstration of what is going on. It's quite powerful," Professor Miller-Jones said.</p> <p dir="ltr">"It tells us a lot about the cluster, and how energy is transported through it."</p> <p dir="ltr">Kimberly Arcand, the principal investigator of the sonification project, described the sound as “a beautiful Hans Zimmer score with the moody level set at really high” when she first heard it in late 2021.</p> <p dir="ltr">“It was such a wonderful representation of what existed in my mind,” she told <em><a href="https://www.washingtonpost.com/technology/2022/08/23/nasa-black-hole-sound/" target="_blank" rel="noopener">The Washington Post</a></em>, adding that it was a “tipping point” for the project in that it “really sparked people’s imagination”.</p> <p dir="ltr">“The idea that there are these supermassive black holes sprinkled throughout the universe that are … belching out incredible songs is a very tantalising thing,” Arcand added.</p> <p dir="ltr">The decision to release the “re-sonification” of the sound waves nearly two decades later came as part of NASA’s efforts to share complex scientific discoveries in plain English with its millions of social media followers.</p> <p dir="ltr"><span id="docs-internal-guid-afb09788-7fff-6723-82cd-3c0338da2593"></span></p> <p dir="ltr">Though some experts have cautioned that NASA’s clip isn’t exactly what you’d hear in space, others argue that it would be realistic to believe that it would be what we’d hear if we had ears that were sensitive enough.</p> <blockquote class="twitter-tweet"> <p dir="ltr" lang="en">I'm not religious, but I'm starting to think that those souls sent to Hell actually end up in a black hole.</p> <p>Sound ON to be horrified <a href="https://t.co/75v74pkkhu">https://t.co/75v74pkkhu</a></p> <p>— Paul Byrne (@ThePlanetaryGuy) <a href="https://twitter.com/ThePlanetaryGuy/status/1562065393581277185?ref_src=twsrc%5Etfw">August 23, 2022</a></p></blockquote> <p dir="ltr">Even so, plenty of social media users have shared their thoughts on the sound, making comparisons to the Lord of the Rings and Silent Hill series or sharing it was an image of an intergalactic puppy overlaid.</p> <p dir="ltr">“I can confirm that the black hole noise Nasa released is the sound of hell,” one user <a href="https://twitter.com/SlimeRegis/status/1562005777488945152" target="_blank" rel="noopener">wrote</a>.</p> <p dir="ltr">“New genre just dropped: Cosmic Horror,” another <a href="https://twitter.com/cybxrart/status/1561690611983343616" target="_blank" rel="noopener">shared</a>.</p> <p dir="ltr"><span id="docs-internal-guid-4a0fce13-7fff-7e3a-478a-a1cb41c49d94"></span></p> <p dir="ltr"><em>Image: @NASAExoplanets (Twitter)</em></p>

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NASA releases highest-resolution images of infrared Universe

<p dir="ltr">New images released by NASA have captured the Universe in a level of detail never before seen and shows a cluster of galaxies as it appeared 4.6 billion years ago.</p> <p dir="ltr">The images, taken by the $13 billion James Webb Space Telescope, depict galaxy cluster <a href="https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet" target="_blank" rel="noopener">SMACS 0723</a> using composite images from its near-infrared camera that were taken at different wavelengths.</p> <p dir="ltr">The galaxy cluster has been photographed previously by the Hubble Space Telescope, though its smaller mirrors and closer orbit to Earth mean its images are less detailed and that it can’t peer back as far in time in comparison to the James Webb telescope, as reported by the <em><a href="https://www.abc.net.au/news/2022-07-13/nasa-webb-hubble-telescope-universe-image-comparison/101233396" target="_blank" rel="noopener">ABC</a></em>.</p> <p dir="ltr">As a result, the structures of distant galaxies are now visible, including clusters of stars and other features, according to a <a href="https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet" target="_blank" rel="noopener">release</a> from NASA.</p> <p dir="ltr">“We are looking back in time to within a billion years after the big bang when viewing the youngest galaxies in this field,” the release reads.</p> <p dir="ltr">In total, four images have been released by NASA, depicting the cosmic cliffs of the <a href="https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-reveals-cosmic-cliffs-glittering-landscape-of-star-birth" target="_blank" rel="noopener">Carina Nebula</a> (a star-forming gaseous cavity created from ultraviolet radiation and stellar winds), <a href="https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-sheds-light-on-galaxy-evolution-black-holes" target="_blank" rel="noopener">Stephen’s Quintet</a> (a group of five growing galaxies which appeared in the film <em>It’s a Wonderful Life</em>), the <a href="https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-captures-dying-star-s-final-performance-in-fine-detail" target="_blank" rel="noopener">Southern Ring Nebula</a> (a dying star surrounded by rings of gas and dust), and SMACS 0723.</p> <p dir="ltr">Spectra of the atmosphere surrounding <a href="https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-reveals-steamy-atmosphere-of-distant-planet-in-detail" target="_blank" rel="noopener">WASP-96 b</a>, a hot gas giant exoplanet, was also released. It shows evidence of water, as well as clouds and haze in the atmosphere of the planet, which orbits a distant Sun-like star.</p> <p dir="ltr">These images and spectra collected from Webb’s other instruments, will be used by scientists to learn more about the masses, ages, histories and compositions of the distant galaxies.</p> <p dir="ltr">Experts from around the world have shared their excitement at the release of the images and what it will mean for future research.</p> <p dir="ltr">“Wow wow wow!!! The Webb telescope continues to absolutely amaze and delight with these first images!” Dr Kim-Vy Tran, an associate professor at UNSW and a professional astronomer, said.</p> <p dir="ltr">“Stephan’s Quintet is a fabulous system of close galaxies, you can almost feel the shockwaves as these galaxies collide and tumble in their cosmic dance. Bound together by gravity, these galaxies are important for understanding the future of galaxies like our Milky Way.</p> <p dir="ltr">The Carinae nebula is also just superb. It’s a stellar nursery full of baby stars where we’re seeing incredible levels of detail for the first time.</p> <p dir="ltr">It’s like before we could see just the trees in the forest, but now we can see down to the branches and even the leaves of individual trees. Some of these baby stars are super-charged giants that are radiating huge amounts of energy, imagine a UV index of a gazillion!"</p> <p dir="ltr">Dr Themiya Nanayakkara, an astronomer at Swinburne University of Technology and the Australian point of contact for the James Webb Space Telescope user support, described seeing the images as “quite humbling”.</p> <p dir="ltr">"It is quite humbling to see the sharpest images of our birth clouds in our cosmic neighbourhood,” Dr Nanayakkara said.</p> <p dir="ltr">“As a person who has spent many nights using the largest telescopes on Earth to detect the faintest signatures of the early cosmos, I feel the transformation to JWST will be game-changing. The released spectra show that we don’t just detect one faint line, we can get the full suite of chemical elements in these galaxies.</p> <p dir="ltr">“This, for the first time, gives us unique human DNA-like signatures of the first galaxies in the Universe to build up the origin story of life and everything around us. And to think of that the most exciting times from this telescope are yet to come!"</p> <p><span id="docs-internal-guid-131f1508-7fff-8c0e-70f5-200ccbb07932"></span></p> <p dir="ltr"><em>Images: </em><em>NASA, ESA, CSA, and STScI</em></p>

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Fragments of a dying comet might put on a spectacular show next week – or pass by without a trace

<p>As Earth orbits the Sun, it ploughs through dust and debris left behind by comets and asteroids. That debris <a href="https://theconversation.com/explainer-why-meteors-light-up-the-night-sky-35754" target="_blank" rel="noopener">gives birth to meteor showers</a> – which can be one of nature’s most amazing spectacles.</p> <p>Most meteor showers are predictable, recurring annually when the Earth traverses a particular trail of debris.</p> <p>Occasionally, however, Earth runs through a particularly narrow, dense clump of debris. This results in a meteor storm, sending <a href="https://blogs.loc.gov/headlinesandheroes/2020/09/how-newspapers-helped-crowdsource-a-scientific-discovery-the-1833-leonid-meteor-storm/#:%7E:text=The%20Leonid%20meteor%20storm%20was,know%20more%20about%20this%20phenomenon." target="_blank" rel="noopener">thousands of shooting stars streaking across the sky each hour</a>.</p> <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=919&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=919&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=919&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=1154&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=1154&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/465041/original/file-20220524-23-pixuou.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=1154&amp;fit=crop&amp;dpr=3 2262w" alt="Artist's impression of the great Leonid meteor storm of 1833" /></a><figcaption><em><span class="caption">Artist’s impression of the 1833 Leonid meteor storm.</span> <span class="attribution"><span class="source">Adolf Vollmy (April 1888)</span></span></em></figcaption></figure> <p>A minor shower called the Tau Herculids could create a meteor storm for observers in the Americas next week. But while some websites promise “the most powerful meteor storm in generations”, astronomers are a little more cautious.</p> <p><strong>Introducing comet SW3</strong></p> <p>The story begins with a comet called <a href="https://cometography.com/pcomets/073p.html" target="_blank" rel="noopener">73P/Schwassmann-Wachmann 3</a> (comet SW3 for short). First spotted in 1930, it is responsible for a weak meteor shower called the Tau Herculids, which nowadays appears to radiate from a point about ten degrees from the bright star Arcturus.</p> <p>In 1995, comet SW3 <a href="https://cometography.com/pcomets/073p.html" target="_blank" rel="noopener">suddenly and unexpectedly brightened</a>. A number of outbursts were observed over a few months. The comet had <a href="https://ui.adsabs.harvard.edu/abs/1996A%26A...310L..17C/abstract" target="_blank" rel="noopener">catastrophically fragmented</a>, releasing huge amounts of dust, gas, and debris.</p> <p>By 2006 (two orbits later), comet SW3 had disintegrated further, into <a href="https://www.nasa.gov/mission_pages/hubble/Comet_73P.html" target="_blank" rel="noopener">several bright fragments accompanied by many smaller chunks</a>.</p> <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=576&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=576&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=576&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=723&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=723&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/465044/original/file-20220524-16-tuml3t.gif?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=723&amp;fit=crop&amp;dpr=3 2262w" alt="Animated images of comet 73P as seen by the Hubble Space Telescope" /></a><figcaption><em><span class="caption">Fragments of comet 73P seen by the Hubble Space Telescope in 2006.</span> <span class="attribution"><span class="source">NASA, ESA, H. Weaver (APL/JHU), M. Mutchler and Z. Levay (STScI)</span></span></em></figcaption></figure> <p><strong>Is Earth on a collision course?</strong></p> <p>This year, Earth will cross comet SW3’s orbit at the end of May.</p> <p>Detailed computer modelling suggests debris has been spreading out along the comet’s orbit like enormous thin tentacles in space.</p> <p>Has the debris spread far enough to encounter Earth? It depends on how much debris was ejected in 1995 and how rapidly that debris was flung outwards as the comet fell apart. But the pieces of dust and debris are so small we can’t see them until we run into them. So how can we get an insight into what might happen next week?</p> <p><strong>Could history repeat itself?</strong></p> <p>Our current understanding of meteor showers began 150 years ago with an event quite similar to SW3’s story.</p> <p>A comet called <a href="https://www.nature.com/articles/061078c0" target="_blank" rel="noopener">comet 3D/Biela</a> was discovered in 1772. It was a short-period comet, like SW3, returning every 6.6 years.</p> <p>In 1846, the comet began to behave strangely. Observers saw its head had split in two, and some described an “archway of cometary matter” between the pieces.</p> <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=283&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=283&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=283&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=356&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=356&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/465046/original/file-20220524-18-2sg6h.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=356&amp;fit=crop&amp;dpr=3 2262w" alt="Sketch of a comet split into two pieces, each with its own tail." /></a><figcaption><em><span class="caption">Sketch of comet 3D/Biela in February 1846, after it split into (at least) two pieces.</span> <span class="attribution"><span class="source">Edmund Weiß</span></span></em></figcaption></figure> <p>At the comet’s next return, in 1852, the two fragments had clearly separated and both were fluctuating unpredictably in brightness.</p> <p>The comet was never seen again.</p> <p>But in late November of 1872, an unexpected meteor storm graced northern skies, stunning observers with rates of more than 3,000 meteors per hour.</p> <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=453&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=453&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=453&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=569&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=569&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/465047/original/file-20220524-22-d7c5zp.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=569&amp;fit=crop&amp;dpr=3 2262w" alt="A paiting showing meteors raining down over mountains" /></a><figcaption><em><span class="caption">The meteor storm of 1872.</span> <span class="attribution"><span class="source">Amedee Guillemin</span></span></em></figcaption></figure> <p>The meteor storm occurred when the Earth crossed 3D/Biela’s orbit: it was where the comet itself should have been two months earlier. A second storm, weaker than the first, occurred in 1885, when the Earth once more encountered the comet’s remains.</p> <p>3D/Biela had disintegrated into rubble, but the two great meteor storms it produced served as a fitting wake.</p> <p>A dying comet, falling apart before our eyes, and an associated meteor shower, usually barely imperceptible against the background noise. Are we about to see history repeat itself with comet SW3?</p> <p><strong>What does this suggest for the Tau Herculids?</strong></p> <p>The main difference between the events of 1872 and this year’s Tau Herculids comes down to the timing of Earth’s crossing of the cometary orbits. In 1872, Earth crossed Biela’s orbit several months <em>after</em> the comet was due, running through material lagging behind where the comet would have been.</p> <p>By contrast, the encounter between Earth and SW3’s debris stream next week happens several months <em>before</em> the comet is due to reach the crossing point. So the debris needs to have spread <em>ahead</em> of the comet for a meteor storm to occur.</p> <p>Could the debris have spread far enough to encounter Earth? Some models suggest we’ll see a strong display from the shower, others suggest the debris will fall just short.</p> <p><strong>Don’t count your meteors before they’ve flashed!</strong></p> <p>Whatever happens, observations of next week’s shower will greatly improve our understanding of how comet fragmentation events happen.</p> <p>Calculations show Earth will <a href="https://www.imo.net/files/meteor-shower/cal2022.pdf" target="_blank" rel="noopener">cross SW3’s orbit at about 3pm, May 31 (AEST)</a>. If the debris reaches far enough forward for Earth to encounter it, then an outburst from the Tau Herculids is likely, but it will only last an hour or two.</p> <p>From Australia, the show (if there is one) will be over before it’s dark enough to see what’s happening.</p> <figure class="align-center zoomable"><em><a href="https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=322&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=322&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=322&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=405&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=405&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/465059/original/file-20220524-22-pmvu1v.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=405&amp;fit=crop&amp;dpr=3 2262w" alt="View of the night sky showing the Tau Herculids radiant" /></a></em><figcaption><em><span class="caption">For observers across Australia, the Tau Herculids radiant is low in the northern sky around 7pm local time.</span> <span class="attribution"><span class="source">Museums Victoria/stellarium</span></span></em></figcaption></figure> <p>Observers in north and south America will, however, have a ringside seat.</p> <p>They are more likely to see a moderate display of slow-moving meteors than a huge storm. This would be a great result, but might be a little disappointing.</p> <p>However, there is a chance the shower could put on a truly spectacular display. Astronomers are travelling across the world, just in case.</p> <p><strong>What about Australian observers?</strong></p> <p>There’s also a small chance any activity will last longer than expected, or even arrive a bit late. Even if you’re in Australia, it’s worth looking up on the evening of May 31, just in case you can get a glimpse of a fragment from a dying comet!</p> <p>The 1995 debris stream is just one of many laid down by the comet in past decades.</p> <p>During the early morning of May 31, around 4am (AEST), Earth will cross debris from the comet’s 1892 passage around the Sun. Later that evening, around 8pm, May 31 (AEST), Earth will cross debris laid down by the comet in 1897.</p> <p>However, debris from those visits will have spread out over time, and therefore we expect only a few meteors to grace our skies from those streams. But, as always, we might be wrong - the only way to know is to go out and see! <img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/182434/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /></p> <figure class="align-center zoomable"><a href="https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=322&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=322&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=322&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=405&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=405&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/465061/original/file-20220524-23-ilm484.png?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=405&amp;fit=crop&amp;dpr=3 2262w" alt="The night sky at midnight, showing the Tau Herculids radiant." /></a><figcaption><em><span class="caption">By midnight (local time), the Tau Herculids radiant will have moved to the north-western sky, seen from across Australia.</span> <span class="attribution"><span class="source">Museums Victoria/Stellarium</span></span></em></figcaption></figure> <p><em><a href="https://theconversation.com/profiles/jonti-horner-3355" target="_blank" rel="noopener">Jonti Horner</a>, Professor (Astrophysics), <a href="https://theconversation.com/institutions/university-of-southern-queensland-1069" target="_blank" rel="noopener">University of Southern Queensland</a> and <a href="https://theconversation.com/profiles/tanya-hill-121214" target="_blank" rel="noopener">Tanya Hill</a>, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), <a href="https://theconversation.com/institutions/museums-victoria-1116" target="_blank" rel="noopener">Museums Victoria</a></em></p> <p><em>This article is republished from <a href="https://theconversation.com" target="_blank" rel="noopener">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/fragments-of-a-dying-comet-might-put-on-a-spectacular-show-next-week-or-pass-by-without-a-trace-182434" target="_blank" rel="noopener">original article</a>.</em></p> <p><em>Image: Getty Images</em></p>

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Satellites interfere with Indigenous astronomy

<p>Since time immemorial, Indigenous peoples worldwide have observed, tracked and memorised all the visible objects in the night sky.</p> <p>This ancient star knowledge was meticulously ingrained with practical knowledge of the land, sky, waters, community and the Dreaming — and passed down through generations.</p> <p>One of the most well-known and celebrated Aboriginal constellations is the Emu in the Sky, which appears in the southern sky early in the year. It is an example of a dark constellation, which means it’s characterised by particularly dark patches in the sky, rather than stars.</p> <p>Conversely, space technology companies such as Starlink are increasingly competing to dominate the skies, and potentially change them forever.</p> <p>The modern-day space race has led to thousands of satellites being scattered through Earth’s outer orbits. If left unchallenged, these companies risk overpopulating an already crowded space environment – potentially pushing dark skies to extinction.</p> <p><strong>Mega-constellations</strong></p> <p>Mega-constellations are groupings of satellites that communicate and work together as they orbit Earth.</p> <p>Since 2018, the Starlink project, run by Elon Musk’s SpaceX, has launched about 1,700 satellites into low Earth orbit. The company plans to launch another <a href="https://www.cnbc.com/2021/08/19/spacex-starlink-satellite-internet-new-capabilities-starship-launch.html" target="_blank" rel="noopener">30,000 over the next decade</a>.</p> <p>British company OneWeb has launched nearly 150 satellites, with plans <a href="https://www.spaceconnectonline.com.au/launch/5111-oneweb-to-deploy-over-half-its-constellation-satellites-this-month" target="_blank" rel="noopener">for another 6,000</a>. And Amazon intends to launch an additional <a href="https://www.cnbc.com/2021/11/01/amazons-project-kuiper-launching-first-internet-satellites-in-q4-2022.html" target="_blank" rel="noopener">3,000 satellites</a> into multiple orbits.</p> <figure class="align-center "><em><img src="https://images.theconversation.com/files/458059/original/file-20220414-20-rmk6kw.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/458059/original/file-20220414-20-rmk6kw.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=337&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/458059/original/file-20220414-20-rmk6kw.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=337&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/458059/original/file-20220414-20-rmk6kw.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=337&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/458059/original/file-20220414-20-rmk6kw.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=424&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/458059/original/file-20220414-20-rmk6kw.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=424&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/458059/original/file-20220414-20-rmk6kw.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=424&amp;fit=crop&amp;dpr=3 2262w" alt="A satellite hovering in orbit above Earth." /></em><figcaption><em><span class="caption">A growing number of Starlink satellites can be found in low orbit around Earth.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/minsk-minskiy-district-belarus-19-january-2110892792" target="_blank" rel="noopener">Shutterstock</a></span></em></figcaption></figure> <p>Each of these companies is taking to the skies to increase internet access across the globe. But even if they deliver on this, sky gazers — and especially Indigenous peoples — are left to wonder: at what cost?</p> <p><strong>Streaks in the night</strong></p> <p>People across the globe began noticing streaks across our skies not long after the first Starlink launch in May 2019. They were unlike anything anyone had seen before.</p> <p>Astronomers are very used to viewing the sky and dealing with interference, often originating from aircraft or the occasional satellite. However, the goal of mega-constellations is to engulf the entire planet, <a href="https://spacenews.com/spacex-launches-another-set-of-starlink-satellites-as-it-nears-global-coverage/" target="_blank" rel="noopener">leaving no place untouched</a>. Mega-constellations alter our collective view of the stars. And there is currently no known way to remove them.</p> <p>One mega-constellation has been observed to <a href="https://www.vox.com/science-and-health/2020/1/7/21003272/space-x-starlink-astronomy-light-pollution" target="_blank" rel="noopener">produce up to 19 parallel streaks</a> across the sky. These streaks disturb astronomical observations, and a significant amount of scientific data can be lost as a result.</p> <figure class="align-center "><img src="https://images.theconversation.com/files/458060/original/file-20220414-17-8ym1fy.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/458060/original/file-20220414-17-8ym1fy.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/458060/original/file-20220414-17-8ym1fy.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/458060/original/file-20220414-17-8ym1fy.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/458060/original/file-20220414-17-8ym1fy.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/458060/original/file-20220414-17-8ym1fy.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/458060/original/file-20220414-17-8ym1fy.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" alt="Satellites leaving streaks in the night sky." /><figcaption><em><span class="caption">Satellites can leave streaks in the night sky.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/starlink-satellites-summer-night-sky-1753118759" target="_blank" rel="noopener">Shutterstock</a></span></em></figcaption></figure> <p>As they travel across the entire sky, scattering the Sun’s light, dark constellations become even fainter — further desecrating Indigenous knowledge and kinship with the environment.</p> <p><a href="https://academic.oup.com/mnrasl/article/504/1/L40/6188393" target="_blank" rel="noopener">Further research</a> on the impacts of mega-constellations have found that as they orbit Earth, the Sun’s rays are reflected off them and scattered into the atmosphere.</p> <p>The authors of that study conclude we are collectively experiencing a new type of “skyglow” as a result: a phenomenon in which the brightness of the sky increases due to human-made light pollution.</p> <p>Initial calculations indicate this new source of light pollution has increased the brightness of night skies globally by about 10%, compared with the natural skyglow measured in the 1960s.</p> <p>Currently, the upper limit of light pollution tolerable at observatories <a href="https://www-cambridge-org.virtual.anu.edu.au/core/journals/transactions-of-the-international-astronomical-union/article/commission-50-identification-and-protection-of-existing-or-potential-observatory-sites-identification-et-protection-des-sites-dobservatoires-existants-ou-potentiels/5483EC52C57F73B2246AF593513A2D9D" target="_blank" rel="noopener">is 10% above the natural skyglow</a>, which suggests we have already reached the limit.</p> <p>In other words, scientific observations of the sky are already at risk of being rendered redundant. If this excess skyglow increases even more, observatories are at serious risk.</p> <p><strong>Indigenous sky sovereignty</strong></p> <p>Indigenous knowledge systems and oral traditions teach us about the intricate and complex relationships Indigenous peoples have with the environment, including the sky.</p> <p>For example, many Aboriginal and Torres Strait Islander cultures have no concept of “outer space”. They only have a continuous and connected reality where coexistence with all things is paramount.</p> <p>As captured by the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0962629818304086?via%3Dihub" target="_blank" rel="noopener">Bawaka Country</a> group, based in northeast Arnhem Land:</p> <blockquote> <p>…to hurt Sky Country, to try and possess it, is an ongoing colonisation of the plural lifeworlds of all those who have ongoing connections with and beyond the sky.</p> </blockquote> <p>Desecrating the sky impacts Indigenous sovereignty as it limits access to their knowledge system, in the same ways desecrating the land has removed First Peoples from their countries, cultures and ways of life.</p> <p>For example, the Gamilaraay and Wiradjuri peoples of New South Wales observe the Emu in the Sky to gauge when it is time to hunt for emu eggs — and most importantly, when it is time to stop. How would the Gamilaraay know when to stop collecting eggs, or when to conduct annual ceremonies signalled by the Celestial Emu, if it was no longer visible?</p> <p>Similarly, important parts of the Jukurrpa, or Dreaming of the Martu people of Western Australia is embedded in the Seven Sisters constellation. How would they keep this knowledge safe if they can’t locate any of the Sisters?</p> <p>Indigenous histories teach us about the devastating consequences of colonialism, and how the impacts of the colonial agenda can be mitigated through prioritising the health of country and community.</p> <p>In the words of <a href="https://www.nature.com/articles/s41550-020-01238-3" target="_blank" rel="noopener">astronomer Aparna Venkatesan and colleagues</a>:</p> <blockquote> <p>…the manner and pace of ‘occupying’ near-Earth space raise the risk of repeating the mistakes of colonisation on a cosmic scale.</p> </blockquote> <p>Active Indigenous sky sovereignty acknowledges the interconnected nature between land and sky, and that caring for country includes sky country. By doing so, it challenges <a href="https://digitalrepository.unm.edu/amst_etds/81/" target="_blank" rel="noopener">the otherwise unimpeded authority</a> of technology corporations.</p> <p><strong>Harming fauna, harming ourselves</strong></p> <p>By understanding that the world (and indeed the Universe) is interconnected, we see that no living creature is immune to the consequences of polluting the skies.</p> <p>Currently, native fauna such as the tammar wallaby, magpie, bogong moth and marine turtles are experiencing a <a href="https://www.awe.gov.au/sites/default/files/documents/national-light-pollution-guidelines-wildlife.pdf" target="_blank" rel="noopener">reduction in populations and quality of life</a> due to the impacts of light-pollution.</p> <figure class="align-center "><em><img src="https://images.theconversation.com/files/458063/original/file-20220414-30327-7xnlx8.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px" srcset="https://images.theconversation.com/files/458063/original/file-20220414-30327-7xnlx8.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/458063/original/file-20220414-30327-7xnlx8.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/458063/original/file-20220414-30327-7xnlx8.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/458063/original/file-20220414-30327-7xnlx8.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/458063/original/file-20220414-30327-7xnlx8.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/458063/original/file-20220414-30327-7xnlx8.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" alt="A tammar wallaby with young in its pouch." /></em><figcaption><em><span class="caption">The tammar wallaby is just one Australian species affected by light pollution.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/wallaby-young-animal-pouch-undergrowth-1840354798" target="_blank" rel="noopener">Shutterstock</a></span></em></figcaption></figure> <p>Migratory species are particularly affected by light pollution, which can result in them losing access to their migratory route. This is a crisis Australia’s fauna has faced since before the introduction of mega-constellations.</p> <p>With more skyglow and light pollution, positive outcomes for native fauna and migratory species diminish.</p> <p><strong>Going forward</strong></p> <p>Several companies have made attempts to reduce the impact of mega-constellations on skyglow.</p> <p>For example, OneWeb has opted to rollout fewer satellites than initially proposed, and has designed them to be positioned at a higher altitude. This means <a href="https://arxiv.org/ftp/arxiv/papers/2012/2012.05100.pdf" target="_blank" rel="noopener">they will produce less skyglow</a>, while also covering a larger area.</p> <p>Starlink, on the other hand, has not shown any public interest in operating at higher and less impactful altitudes, for fears it will <a href="https://arstechnica.com/tech-policy/2021/04/fcc-lets-spacex-cut-satellite-altitude-to-improve-starlink-speed-and-latency/" target="_blank" rel="noopener">impact the Starlink network’s speed and latency.</a></p> <p>That said, they have attempted to reduce their satellites’ luminosity by painting them with a novel anti-reflective coating. Coating techniques have demonstrated a reduction in reflected sunlight by up to 50%. Unfortunately, not all wavelengths of <a href="https://arxiv.org/abs/2010.04655" target="_blank" rel="noopener">light being scattered are reduced using this method</a>. So multi-wave astronomy, and different species of animals, are still at risk.</p> <p>We’ll need more solutions to navigate our increasingly polluted atmosphere, particularly if communication monopolies continue to rein over near-Earth space.</p> <p>Just as some companies have started considering tactics to avoid increasing skyglow, all space tech companies must be held responsible for adding to an already polluted space.</p> <p>Guidelines such as those set by the Inter-Agency Space Debris Coordination Committee offer solutions to this problem. They suggest lowering the height of a satellite’s orbit when it’s no longer needed, <a href="https://www.nature.com/articles/d41586-018-06170-1" target="_blank" rel="noopener">allowing it to disintegrate as it falls</a> down to Earth.</p> <p>However, these are international guidelines, so there’s no legal framework to enforce such practices.</p> <p>And given that near-miss collisions have already <a href="https://techcrunch.com/2019/09/03/near-miss-between-science-craft-and-starlink-satellite-shows-need-to-improve-orbital-coordination/" target="_blank" rel="noopener">taken place between some mega-constellations</a>, and an estimated 20,000 pieces of space debris already floating above, reducing orbital pollution must also now be a priority.</p> <p>Reducing air pollutants has also been shown to drastically <a href="https://doi.org/10.1093/mnrasl/slab030" target="_blank" rel="noopener">decrease natural sky brightness</a>, offering a potential solution for improving night sky visibility — not to mention cleaner breathing air for all.</p> <p>In valuing Indigenous knowledge systems, that value must be extended to the natural environment in which that knowledge is embedded and founded upon. In Australia, preserving dark skies is not just vital for the continuation of Indigenous knowledge and astronomers — it benefits us all.</p> <p>A major tenet of life for Indigenous peoples is valuing the sustainability of one’s actions. By adopting this at a larger scale, we could create a reality in which we’re not a threat to our own survival.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important;" src="https://counter.theconversation.com/content/173840/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /></p> <p><em><a href="https://theconversation.com/profiles/karlie-noon-1310291" target="_blank" rel="noopener">Karlie Noon</a>, Astronomer, <a href="https://theconversation.com/institutions/australian-national-university-877" target="_blank" rel="noopener">Australian National University</a></em></p> <p><em>This article is republished from <a href="https://theconversation.com" target="_blank" rel="noopener">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/thousands-of-satellites-are-polluting-australian-skies-and-threatening-ancient-indigenous-astronomy-practices-173840" target="_blank" rel="noopener">original article</a>.</em></p> <p><em>Image: Getty Images</em></p>

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Rare full moon with occur on Christmas Day this year

<p>For the first time in decades, the last full moon of 2015 will occur on Christmas day this year. Also known as a Full Cold Moon, as our Northern hemisphere neighbours experience the phenomenon in the winter, the full moon will reach its peak at 6:11am EST.</p> <p>The astronomical event is called apogee, and occurs when the moon reaches its furthest orbit from Earth, at over 407,000 kilometres away. It has not occurred since 1977, and this year, the moon is also said to be the smallest it’s been since 2004.</p> <p>NASA have announced the moon will be bright enough to cast shadows. It should be clearly visible through a telescope or binoculars if weather permits.</p> <p>“As we look at the moon on such an occasion, it's worth remembering that the moon is more than just a celestial neighbour," says NASA’s John Keller. "The geologic history of the moon and Earth are intimately tied together such that the Earth would be a dramatically different planet without the moon."</p> <p>NASA forecast Christmas and the final full moon won’t coincide again until 2034, so be sure to catch this beautiful natural phenomenon while it lasts!</p> <p><strong>Related links: </strong></p> <p><strong><em><a href="http://www.oversixty.co.nz/health/wellbeing/2015/08/cures-from-the-kitchen-cupboard/">8 kitchen cupboard cures for common ailments</a></em></strong></p> <p><strong><em><a href="http://www.oversixty.co.nz/health/wellbeing/2015/09/old-wives-tale-medical-advice/">Odd medical advice your mother probably told you</a></em></strong></p> <p><strong><a href="http://www.oversixty.co.nz/health/wellbeing/2015/09/monday-music-playlist/"><em>Catchy songs to beat the Monday blues</em></a></strong></p>

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