tag:theconversation.com,2011:/fr/topics/radio-telescope-13650/articlesRadio telescope – The Conversation2024-02-05T13:30:46Ztag:theconversation.com,2011:article/2198922024-02-05T13:30:46Z2024-02-05T13:30:46ZUS Moon landing marks new active phase of lunar science, with commercial launches of landers that will study solar wind and peer into the universe’s dark ages<figure><img src="https://images.theconversation.com/files/567940/original/file-20240104-21-s3p58r.jpg?ixlib=rb-1.1.0&rect=4%2C17%2C2991%2C1868&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The dark, far side of the Moon is the perfect place to conduct radio astronomy. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/LunarEclipse/704e3da2df90473486270e23aa73419d/photo?Query=moon&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=399&digitizationType=Digitized&currentItemNo=12&vs=true&vs=true">AP Photo/Rick Bowmer</a></span></figcaption></figure><p>For the first time since 1972, NASA <a href="https://www.intuitivemachines.com/im-1">landed a craft on the surface of the Moon</a> in February 2024. But the agency didn’t do it alone – instead, it partnered with commercial companies. Thanks to new technologies and <a href="https://www.nasa.gov/commercial-lunar-payload-services/">public-private partnerships</a>, the scientific projects brought to the Moon on this craft and on future missions like it will open up new realms of scientific possibility. </p>
<p>As parts of several projects launching this year, teams of scientists, including myself, will conduct radio astronomy from the south pole and the far side of the Moon.</p>
<p>NASA’s <a href="https://www.nasa.gov/commercial-lunar-payload-services/">commercial lunar payload services program</a>, or CLPS, will use uncrewed landers to conduct NASA’s first science experiments from the Moon in over 50 years. The CLPS program differs from past space programs. Rather than NASA building the landers and operating the program, commercial companies will do so in a public-private partnership. NASA identified <a href="https://www.nasa.gov/commercial-lunar-payload-services/clps-providers/">about a dozen companies</a> to serve as vendors for landers that will go to the Moon. </p>
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<figcaption><span class="caption">CLPS will send science payloads to the Moon in conjunction with the Artemis program’s crewed missions.</span></figcaption>
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<p>NASA buys space on these landers for <a href="https://science.nasa.gov/lunar-science/clps-deliveries/">science payloads</a> to fly to the Moon, and the companies design, build and insure the landers, as well as contract with rocket companies for the launches. Unlike in the past, NASA is one of the customers and not the sole driver. </p>
<h2>Peregrine and Odysseus, the first CLPS landers</h2>
<p>The first two CLPS payloads are scheduled to launch during the first two months of 2024. There’s the <a href="https://science.nasa.gov/lunar-science/clps-deliveries/to2-astrobotic/">Astrobotics payload</a>, which launched Jan. 8 before its lander, named Peregrine, <a href="https://www.space.com/astrobotic-peregrine-moon-lander-headed-to-earth">experienced a fuel issue</a> that cut its journey to the Moon short. </p>
<p>Next, there’s the <a href="https://science.nasa.gov/lunar-science/clps-deliveries/op-to2-intuitive-machines/">Intuitive Machines payload</a>. Intuitive Machines’ lander, named Odysseus, <a href="https://www.intuitivemachines.com/im-1">landed near the south pole of the Moon</a> on Feb. 22, 2024. NASA has also planned a <a href="https://science.nasa.gov/lunar-science/clps-deliveries/">few additional landings</a> – about two or three per year – for each of the next few years.</p>
<p>I’m a <a href="https://www.colorado.edu/faculty/burns/">radio astronomer</a> and co-investigator on NASA’s <a href="https://www.colorado.edu/ness/projects/radiowave-observations-lunar-surface-photoelectron-sheath-rolses">ROLSES program</a>, otherwise known as Radiowave Observations at the Lunar Surface of the photoElectron Sheath. ROLSES was built by the NASA Goddard Space Flight Center and is led by <a href="https://science.gsfc.nasa.gov/sci/bio/natchimuthuk.gopalswamy-1">Natchimuthuk Gopalswamy</a>. </p>
<p>The ROLSES instrument landed on the Moon as <a href="https://www.intuitivemachines.com/_files/ugd/7c27f7_51f84ee63ea744a9b7312d17fefa9606.pdf">one of six NASA payloads</a> on the Intuitive Machines lander in February. Between ROLSES and another mission scheduled for the lunar far side in two years, LuSEE-Night, our teams will land NASA’s first two radio telescopes on the Moon by 2026. </p>
<h2>Radio telescopes on the Moon</h2>
<p>The Moon – particularly the far side of the Moon – is an ideal place to do radio astronomy and study signals from extraterrestrial objects such as the Sun and the Milky Way galaxy. On Earth, the ionosphere, which <a href="https://theconversation.com/earths-magnetic-field-protects-life-on-earth-from-radiation-but-it-can-move-and-the-magnetic-poles-can-even-flip-216231">contains Earth’s magnetic field</a>, distorts and absorbs radio signals below the <a href="https://www.fcc.gov/general/fm-radio">FM band</a>. These signals might get scrambled or may not even make it to the surface of the Earth.</p>
<p>On Earth, there are also TV signals, satellite broadcasts and defense radar systems <a href="https://theconversation.com/radio-interference-from-satellites-is-threatening-astronomy-a-proposed-zone-for-testing-new-technologies-could-head-off-the-problem-199353">making noise</a>. To do higher sensitivity observations, you have to go into space, away from Earth. </p>
<p>The Moon is what scientists call <a href="https://www.sciencefocus.com/space/what-is-tidal-locking">tidally locked</a>. One side of the Moon is always facing the Earth – the “<a href="https://www.rmg.co.uk/stories/topics/what-man-moon">man in the Moon</a>” side – and the other side, <a href="https://theconversation.com/whats-on-the-far-side-of-the-moon-111306">the far side</a>, always faces away from the Earth. The Moon has no ionosphere, and with about 2,000 miles of rock between the Earth and the far side of the Moon, there’s no interference. It’s radio quiet. </p>
<p>For our first mission with ROLSES, which launched in February 2024, we will collect data about environmental conditions on the Moon near its south pole. On the Moon’s surface, <a href="https://theconversation.com/solar-storms-can-destroy-satellites-with-ease-a-space-weather-expert-explains-the-science-177510">solar wind</a> directly strikes the lunar surface and creates a charged gas, called <a href="https://www.psfc.mit.edu/vision/what_is_plasma">a plasma</a>. Electrons lift off the negatively charged surface to form a highly ionized gas. </p>
<p>This doesn’t happen on Earth because <a href="https://theconversation.com/earths-magnetic-field-protects-life-on-earth-from-radiation-but-it-can-move-and-the-magnetic-poles-can-even-flip-216231">the magnetic field deflects</a> the solar wind. But there’s no global magnetic field on the Moon. With a low frequency radio telescope like ROLSES, we’ll be able to measure that plasma for the first time, which could help scientists figure out how to keep astronauts safe on the Moon. </p>
<p>When astronauts walk around on the surface of the Moon, they’ll pick up different charges. It’s like walking across the carpet with your socks on – when you reach for a doorknob, a spark can come out of your finger. The same kind of discharge happens on the Moon from the charged gas, but it’s potentially more harmful to astronauts. </p>
<h2>Solar and exoplanet radio emissions</h2>
<p>Our team is also going to use ROLSES to look at the Sun. The Sun’s surface releases shock waves that send out highly energetic particles and low radio frequency emissions. We’ll use the radio telescopes to measure these emissions and to see bursts of low-frequency radio waves from shock waves within the solar wind.</p>
<p>We’re also going to examine the Earth from the surface of the Moon and use that process as a template for <a href="https://theconversation.com/nasas-tess-spacecraft-is-finding-hundreds-of-exoplanets-and-is-poised-to-find-thousands-more-122104">looking at radio emissions from exoplanets</a> that may harbor life <a href="https://theconversation.com/are-there-any-planets-outside-of-our-solar-system-164062">in other star systems</a>. </p>
<p>Magnetic fields are important for life because they shield the planet’s surface from the <a href="https://theconversation.com/the-scorching-winds-on-the-surface-of-the-sun-and-how-were-forecasting-them-44098">solar/stellar wind</a>. </p>
<p>In the future, our team hopes to use specialized arrays of antennas on the far side of the Moon to observe nearby stellar systems that are known to have exoplanets. If we detect the same kind of radio emissions that come from Earth, this will tell us that the planet has a magnetic field. And we can measure the strength of the magnetic field to figure out whether it’s strong enough to shield life.</p>
<h2>Cosmology on the Moon</h2>
<p>The Lunar Surface Electromagnetic Experiment at Night, or <a href="https://www.colorado.edu/ness/projects/lunar-surface-electromagnetics-experiment-night-lusee-night">LuSEE-Night</a>, will fly in early 2026 to the far side of the Moon. LuSEE-Night marks scientists’ first attempt to do cosmology on the Moon.</p>
<p>LuSEE-Night is a novel collaboration between NASA and the Department of Energy. Data will be sent back to Earth using a communications satellite in lunar orbit, <a href="https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/A_pathway_for_communicating_at_the_Moon">Lunar Pathfinder</a>, which is funded by the European Space Agency.</p>
<p>Since the far side of the Moon is <a href="https://cosmicdawn.astro.ucla.edu/lunar_telescopes.html">uniquely radio quiet</a>, it’s the best place to do cosmological observations. During the two weeks of lunar night that happen every 14 days, there’s no emission coming from the Sun, and there’s no ionosphere. </p>
<p>We hope to study an unexplored part of the early universe called the <a href="https://www.astronomy.com/science/the-beginning-to-the-end-of-the-universe-the-cosmic-dark-ages/">dark ages</a>. The dark ages refer to before and just after the formation of the very first stars and galaxies in the universe, which is beyond what the <a href="https://webb.nasa.gov/">James Webb Space Telescope</a> can study.</p>
<p>During the dark ages, the universe was less than 100 million years old – today the universe is 13.7 billion years old. The universe was full of hydrogen <a href="https://theconversation.com/after-our-universes-cosmic-dawn-what-happened-to-all-its-original-hydrogen-65527">during the dark ages</a>. That hydrogen radiates through the universe at low radio frequencies, and when new stars turn on, they ionize the hydrogen, producing a radio signature in the spectrum. Our team hopes to measure that signal and learn about how the earliest stars and galaxies in the universe formed.</p>
<p>There’s also a lot of potential new physics that we can study in this last unexplored cosmological epoch in the universe. We will investigate the nature of <a href="https://theconversation.com/dark-matter-the-mystery-substance-physics-still-cant-identify-that-makes-up-the-majority-of-our-universe-85808">dark matter</a> and early <a href="https://theconversation.com/explainer-the-mysterious-dark-energy-that-speeds-the-universes-rate-of-expansion-40224">dark energy</a> and test our fundamental models of physics and cosmology in an unexplored age.</p>
<p>That process is going to start in 2026 with the LuSEE-Night mission, which is both a fundamental physics experiment and a cosmology experiment.</p>
<p><em>This is an updated version of an article originally published on Feb. 5, 2024.</em></p><img src="https://counter.theconversation.com/content/219892/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jack Burns receives funding from NASA.</span></em></p>Projects under NASA’s CLPS program – including the Odysseus lander that made it to the lunar surface – will probe unexplored questions about the universe’s formation.Jack Burns, Professor of Astrophysical and Planetary Sciences, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2043512023-05-03T12:10:32Z2023-05-03T12:10:32ZAI is helping astronomers make new discoveries and learn about the universe faster than ever before<figure><img src="https://images.theconversation.com/files/523645/original/file-20230501-18-4e90m3.jpg?ixlib=rb-1.1.0&rect=0%2C299%2C4895%2C3031&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The sky is big and full of information that AI tools can help astronomers unlock. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/paul-wild-observatory-under-starry-sky-royalty-free-image/637273906?phrase=telescope+with+milky+way&adppopup=true">Yuga Kurita/Moment via Getty Images</a></span></figcaption></figure><p>The famous first image of a black hole <a href="https://doi.org/10.3847/2041-8213/acc32d">just got two times sharper</a>. A research team used artificial intelligence to dramatically improve upon <a href="https://doi.org/10.3847/2041-8213/ab0ec7">its first image</a> from 2019, which now shows the black hole at the center of the M87 galaxy as darker and bigger than the first image depicted.</p>
<p>I’m an <a href="https://scholar.google.com/citations?user=OrRLRQ4AAAAJ&hl=en">astronomer</a> who studies and has written about <a href="https://wwnorton.com/books/9780393343861">cosmology</a>, <a href="https://wwnorton.com/books/9780393357509">black holes</a> and <a href="https://www.penguinrandomhouse.com/books/718149/worlds-without-end-by-chris-impey/">exoplanets</a>. Astronomers have been using AI for decades. In fact, in 1990, astronomers from the University of Arizona, where I am a professor, were among the <a href="https://www.datasciencecentral.com/the-evolution-of-astronomical-ai/">first to use a type of AI called a neural network</a> to study the shapes of galaxies. </p>
<p>Since then, AI has spread into every field of astronomy. As the technology has become more powerful, AI algorithms have begun helping astronomers tame massive data sets and discover new knowledge about the universe.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523641/original/file-20230501-18-3sjj1h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A group of radio antennas pointed at the sky." src="https://images.theconversation.com/files/523641/original/file-20230501-18-3sjj1h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523641/original/file-20230501-18-3sjj1h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523641/original/file-20230501-18-3sjj1h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523641/original/file-20230501-18-3sjj1h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523641/original/file-20230501-18-3sjj1h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523641/original/file-20230501-18-3sjj1h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523641/original/file-20230501-18-3sjj1h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Astronomy is no longer limited to just optical images – radio telescopes produce huge amounts of data that researchers need to process.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/observatory-antenna-in-the-sunse-royalty-free-image/1309400138?phrase=astronomy+data&adppopup=true">Wenbin/Moment via Getty Images</a></span>
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<h2>Better telescopes, more data</h2>
<p>As long as astronomy has been a science, it has involved trying to make sense of the multitude of objects in the night sky. That was relatively simple when the only tools were the naked eye or a simple telescope, and all that could be seen were a few thousand stars and a handful of planets.</p>
<p>A hundred years ago, Edwin Hubble used newly built telescopes to show that the universe is filled with not just stars and clouds of gas, <a href="https://www.nasa.gov/content/about-story-edwin-hubble">but countless galaxies</a>. As telescopes have continued to improve, the sheer number of celestial objects humans can see and the <a href="https://events.asiaa.sinica.edu.tw/school/20170904/talk/djorgovski1.pdf">amount of data</a> astronomers need to sort through have both grown exponentially, too.</p>
<p>For example, the soon-to-be-completed <a href="https://www.lsst.org/about">Vera Rubin Observatory</a> in Chile will make images so large that it would take 1,500 high-definition TV screens to view each one in its entirety. Over 10 years it is expected to generate 0.5 exabytes of data – about 50,000 times the amount of information held in all of the books contained within the Library of Congress. </p>
<p>There are 20 telescopes with mirrors larger than 20 feet (6 meters) in diameter. AI algorithms are the only way astronomers could ever hope to work through all of the data available to them today. There are a number of ways AI is proving useful in processing this data.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523642/original/file-20230501-292-iuhviz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A sky filled with galaxies." src="https://images.theconversation.com/files/523642/original/file-20230501-292-iuhviz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523642/original/file-20230501-292-iuhviz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523642/original/file-20230501-292-iuhviz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523642/original/file-20230501-292-iuhviz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523642/original/file-20230501-292-iuhviz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523642/original/file-20230501-292-iuhviz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523642/original/file-20230501-292-iuhviz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">One of the earliest uses of AI in astronomy was to pick out the multitude of faint galaxies hidden in the background of images.</span>
<span class="attribution"><a class="source" href="https://flickr.com/photos/nasawebbtelescope/52777397541/">ESA/Webb, NASA & CSA, J. Rigby</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
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<h2>Picking out patterns</h2>
<p>Astronomy often involves looking for needles in a haystack. About 99% of the pixels in an astronomical image contain background radiation, light from other sources or the blackness of space – only 1% have the subtle shapes of faint galaxies. </p>
<p>AI algorithms – in particular, neural networks that use many interconnected nodes and are able to learn to recognize patterns – are perfectly suited for picking out the patterns of galaxies. Astronomers began <a href="https://doi.org/10.1111/j.1365-2966.2010.16713.x">using neural networks to classify galaxies</a> in the early 2010s. Now the algorithms <a href="https://www.nao.ac.jp/en/news/science/2020/20200811-subaru.html">are so effective</a> that they can classify galaxies with an accuracy of 98%.</p>
<p>This story has been repeated in other areas of astronomy. Astronomers working on SETI, the Search for Extraterrestrial Intelligence, use radio telescopes to look for signals from distant civilizations. Early on, radio astronomers scanned charts by eye to <a href="https://earthsky.org/space/wow-signal-explained-comets-antonio-paris/">look for anomalies</a> that couldn’t be explained. More recently, researchers harnessed 150,000 personal computers and 1.8 million citizen scientists to look for artificial <a href="https://www.nytimes.com/2020/03/23/science/seti-at-home-aliens.html">radio signals</a>. Now, researchers are using AI to sift through reams of data much more quickly and thoroughly than people can. This has allowed SETI efforts to cover more ground while also greatly reducing the <a href="https://doi.org/10.1038/s41550-022-01872-z">number of false positive signals</a>.</p>
<p>Another example is the search for exoplanets. Astronomers discovered most of the <a href="https://exoplanets.nasa.gov/">5,300 known exoplanets</a> by measuring a dip in the amount of light coming from a star <a href="https://exoplanets.nasa.gov/resources/2338/exoplanet-detection-transit-method/">when a planet passes in front of it</a>. AI tools can now pick out the signs of an exoplanet with <a href="https://doi.org/10.48550/arXiv.2011.14135">96% accuracy</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523643/original/file-20230501-16-xeiogk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A planet near a dim red star." src="https://images.theconversation.com/files/523643/original/file-20230501-16-xeiogk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523643/original/file-20230501-16-xeiogk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523643/original/file-20230501-16-xeiogk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523643/original/file-20230501-16-xeiogk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523643/original/file-20230501-16-xeiogk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523643/original/file-20230501-16-xeiogk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523643/original/file-20230501-16-xeiogk.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">AI tools can help astronomers discover new exoplanets like TRAPPIST-1 b.</span>
<span class="attribution"><a class="source" href="https://flickr.com/photos/nasawebbtelescope/52775409328/">NASA, ESA, CSA, Joseph Olmsted (STScI)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Making new discoveries</h2>
<p>AI has proved itself to be excellent at identifying known objects – like galaxies or exoplanets – that astronomers tell it to look for. But it is also quite powerful at finding objects or phenomena that are theorized but have not yet been discovered in the real world.</p>
<p>Teams have used this approach to detect <a href="https://www.sciencedaily.com/releases/2023/02/230207144222.htm">new exoplanets</a>, learn about the <a href="https://www.quantamagazine.org/with-ai-astronomers-dig-up-the-stars-that-birthed-the-milky-way-20230328/">ancestral stars</a> that led to the formation and growth of the Milky Way, and predict the signatures of new types of <a href="https://cerncourier.com/a/gravitational-wave-astronomy-turns-to-ai/">gravitational waves</a>.</p>
<p>To do this, astronomers first use AI to convert theoretical models into observational signatures – including realistic levels of noise. They then use machine learning to sharpen the ability of AI to detect the predicted phenomena.</p>
<p>Finally, radio astronomers have also been using AI algorithms to sift through signals that don’t correspond to known phenomena. Recently a team from South Africa found a <a href="https://www.biznews.com/global-citizen/2023/04/06/machine-learnings-discovery-astronomy">unique object</a> that may be a remnant of the explosive merging of two supermassive black holes. If this proves to be true, the data will allow a new test of general relativity – Albert Einstein’s <a href="https://theconversation.com/why-does-gravity-pull-us-down-and-not-up-162141">description of space-time</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523644/original/file-20230501-22-dihfie.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two side-by-side images of an orange circular haze around a dark center." src="https://images.theconversation.com/files/523644/original/file-20230501-22-dihfie.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523644/original/file-20230501-22-dihfie.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=301&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523644/original/file-20230501-22-dihfie.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=301&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523644/original/file-20230501-22-dihfie.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=301&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523644/original/file-20230501-22-dihfie.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=378&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523644/original/file-20230501-22-dihfie.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=378&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523644/original/file-20230501-22-dihfie.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=378&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 team that first imaged a black hole, at left, used AI to generate a sharper version of the image, at right, showing the black hole to be larger than originally thought.</span>
<span class="attribution"><a class="source" href="https://iopscience.iop.org/article/10.3847/1538-4357/acaa9a/meta">Medeiros et al 2023</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Making predictions and plugging holes</h2>
<p>As in many areas of life recently, generative AI and large language models like ChatGPT are also making waves in the astronomy world.</p>
<p>The team that created the first image of a black hole in 2019 used a <a href="https://doi.org/10.3847/2041-8213/acc32d">generative AI to produce its new image</a>. To do so, it first taught an AI how to recognize black holes by feeding it simulations of many kinds of black holes. Then, the team used the AI model it had built to fill in gaps in the massive amount of data collected by the radio telescopes on the black hole M87. </p>
<p>Using this simulated data, the team was able to create a new image that is two times sharper than the original and is fully consistent with the predictions of general relativity.</p>
<p>Astronomers are also turning to AI to help tame the complexity of modern research. A team from the Harvard-Smithsonian Center for Astrophysics created a <a href="https://doi.org/10.48550/arXiv.2212.00744">language model called astroBERT</a> to read and organize 15 million scientific papers on astronomy. Another team, based at NASA, has even proposed using AI to <a href="https://www.technologyreview.com/2021/09/20/1035890/ai-predict-astro2020-decadal-survey/">prioritize astronomy projects</a>, a process that astronomers engage in every 10 years.</p>
<p>As AI has progressed, it has become an essential tool for astronomers. As telescopes get better, as data sets get larger and as AIs continue to improve, it is likely that this technology will play a central role in future discoveries about the universe.</p><img src="https://counter.theconversation.com/content/204351/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Impey receives funding from the National Science Foundation and Epic Games.</span></em></p>Artificial intelligence tools are making waves in almost every aspect of life, and astronomy is no different. An astronomer explains the history and future of AI in understanding the universe.Chris Impey, University Distinguished Professor of Astronomy, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1993532023-03-03T13:24:40Z2023-03-03T13:24:40ZRadio interference from satellites is threatening astronomy – a proposed zone for testing new technologies could head off the problem<figure><img src="https://images.theconversation.com/files/513013/original/file-20230301-20-knf7oq.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1281%2C1281&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Radio observatories like the Green Bank Telescope are in radio quiet zones that protect them from interference.</span> <span class="attribution"><a class="source" href="https://public.nrao.edu/gallery/green-bank-telescope/">NRAO/AUI/NSF</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Visible light is just one part of the electromagnetic spectrum that astronomers use to study the universe. The <a href="https://theconversation.com/the-james-webb-space-telescope-is-finally-ready-to-do-science-and-its-seeing-the-universe-more-clearly-than-even-its-own-engineers-hoped-for-184989">James Webb Space Telescope</a> was built to see infrared light, other <a href="https://swift.gsfc.nasa.gov/">space telescopes capture X-ray images</a>, and observatories like the <a href="https://greenbankobservatory.org/science/telescopes/gbt/">Green Bank Telescope</a>, the <a href="https://public.nrao.edu/telescopes/VLA/">Very Large Array</a>, the <a href="http://www.almaobservatory.org/">Atacama Large Millimeter Array</a> and dozens of other observatories around the world work at radio wavelengths. </p>
<p>Radio telescopes are facing a problem. All satellites, whatever their function, use radio waves to transmit information to the surface of the Earth. Just as <a href="https://theconversation.com/night-skies-are-getting-9-6-brighter-every-year-as-light-pollution-erases-stars-for-everyone-199383">light pollution can hide a starry night sky</a>, radio transmissions can swamp out the radio waves astronomers use to learn about black holes, newly forming stars and the evolution of galaxies.</p>
<p>We are three scientists who work in <a href="https://www.researchgate.net/profile/Christopher-De-Pree">astronomy</a> and <a href="https://scholar.google.com/citations?user=y5L4A3gAAAAJ&hl=en&oi=ao">wireless</a> <a href="https://scholar.google.com/citations?user=eEqTPcwAAAAJ&hl=en&oi=ao">technology</a>. With <a href="https://theconversation.com/how-many-satellites-are-orbiting-earth-166715">tens of thousands of satellites</a> expected to go into orbit in the coming years and increasing use on the ground, the radio spectrum is getting crowded. Radio quiet zones – regions, usually located in remote areas, where ground-based radio transmissions are limited or prohibited – have protected radio astronomy in the past.</p>
<p>As the problem of radio pollution continues to grow, scientists, engineers and policymakers will need to figure out how everyone can effectively share the limited range of radio frequencies. One solution that we have been working on for the past few years is to create a facility where astronomers and engineers <a href="https://beta.nsf.gov/funding/opportunities/spectrum-innovation-initiative-national-radio">can test new technologies</a> to prevent radio interference from blocking out the night sky.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing what wavelengths of light correspond with different types of radiation." src="https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=227&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=227&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=227&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=286&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=286&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=286&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Different telescopes capture different parts of the electromagnetic spectrum, with radio telescopes collecting radiation of the longest wavelengths.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:EM_Spectrum_Properties_edit.svg">InductiveLoad/NASA/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Astronomy with radio waves</h2>
<p>Radio waves are the longest wavelength emissions on the electromagnetic spectrum, meaning that the distance between two peaks of the wave is relatively far apart. Radio telescopes collect radio waves in wavelengths from millimeter to meter wavelengths. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An orange ring surrounding a dark center." src="https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The first direct image of a black hole was created using the Event Horizon Telescope, combining observations from eight radio telescopes.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Black_hole_-_Messier_87_crop_max_res.jpg#/media/File:Black_hole_-_Messier_87_crop_max_res.jpg">European Southern Observatory/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Even if you are unfamiliar with radio telescopes, you have probably heard about some of the research they do. The fantastic <a href="https://public.nrao.edu/gallery/astronomers-capture-first-image-of-a-black-hole/">first images of accretion disks</a> around <a href="https://theconversation.com/say-hello-to-sagittarius-a-the-black-hole-at-the-center-of-the-milky-way-galaxy-183008">black holes</a> were both produced by the <a href="https://eventhorizontelescope.org/about">Event Horizon Telescope</a>. This telescope is a global network of eight radio telescopes, and each of the individual telescopes that make up the Event Horizon Telescope is located in a place with very little radio frequency interference: a radio quiet zone.</p>
<p>A radio quiet zone is a region where ground-based transmitters, like cellphone towers, are required to lower their power levels so as not to affect sensitive radio equipment. The U.S. has two such zones. The largest is the <a href="https://info.nrao.edu/do/spectrum-management/national-radio-quiet-zone-nrqz-1">National Radio Quiet Zone</a>, which covers 13,000 square miles (34,000 square kilometers) mostly in West Virginia and Virginia. It contains the <a href="https://greenbankobservatory.org">Green Bank Observatory</a>. The other, <a href="https://its.ntia.gov/research-topics/table-mountain/tm-home/">the Table Mountain Field Site and Radio Quiet Zone</a>, in Colorado, supports research by a number of federal agencies.</p>
<p>Similar radio quiet zones are home to telescopes in <a href="https://www.csiro.au/en/about/facilities-collections/atnf/mro">Australia</a>, <a href="https://www.sarao.ac.za/science/meerkat/about-meerkat/">South Africa</a> and <a href="https://doi.org/10.1109/APEMC.2013.7360597">China</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/pgysWWwESfU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Large satellite constellations, like those of Starlink, can be seen marching in lines across night skies and harm both visible and radio astronomy.</span></figcaption>
</figure>
<h2>A satellite boom</h2>
<p>On Oct. 4, 1957, the Soviet Union launched Sputnik into orbit. As the small satellite circled the globe, amateur radio enthusiasts all over the world were able to <a href="https://ethw.org/Sputnik">pick up the radio signals</a> it was beaming back to Earth. Since that historic flight, wireless signals have become part of almost every aspect of modern life – from aircraft navigation to Wi-Fi – and the <a href="https://theconversation.com/how-many-satellites-are-orbiting-earth-166715">number of satellites has grown exponentially</a>. </p>
<p>The more radio transmissions there are, the more challenging it becomes to deal with <a href="https://researchrepository.wvu.edu/etd/11467/">interference in radio quiet zones</a>. Existing laws do not protect these zones from satellite transmitters, which can have devastating effects. In one example, transmissions from an Iridium satellite <a href="https://nap.nationalacademies.org/catalog/12800/spectrum-management-for-science-in-the-21st-century">completely obscured</a> the observations of a faint star made in a protected band allocated to radio astronomy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="One chart showing a single object and another showing a mess of lines." src="https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=296&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=296&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=296&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=372&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=372&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=372&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Two images from the Very Large Array in New Mexico show what a faint star looks like to a radio telescope without satellite interference, left, and with satellite interference, right.</span>
<span class="attribution"><span class="source">G. Taylor, UNM</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Satellite internet networks like Starlink, OneWeb and others will eventually be flying over every location on Earth and transmitting radio waves down to the surface. Soon, no location will be truly quiet for radio astronomy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The light pollution of a large city against the night sky." src="https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.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">Just as with light pollution, the more development there is on Earth and in the sky, the more radio interference there will be.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:San_Tan_Mountain_Lights.jpg">Gppercy/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Interference in the sky and on the ground</h2>
<p>The <a href="https://science.nrao.edu/facilities/vla/docs/manuals/obsguide/rfi">problem of radio interference is not new</a>.</p>
<p>In the 1980s, the Russian <a href="https://glonass-iac.ru/en/about_glonass/">Global Navigation Satellite System</a> – essentially the Soviet Union’s version of GPS – <a href="http://www.iucaf.org/sschool/procs/glonass.pdf">began transmitting at a frequency</a> that was officially protected for <a href="https://hal-enac.archives-ouvertes.fr/hal-01022448/document">radio astronomy</a>. Researchers <a href="https://arxiv.org/abs/astro-ph/0002516">recommended a number of fixes</a> for this interference. By the time operators of the Russian navigation system agreed to change the transmitting frequency of the satellites, <a href="https://adsabs.harvard.edu/full/1994PASP..106..807C">a lot of harm</a> had already been done due to the lack of testing and communication.</p>
<p>Many satellites look down at Earth using parts of the radio spectrum to monitor characteristics like <a href="https://land.copernicus.eu/global/products/ssm">surface soil moisture</a> that are important for weather prediction and climate research. The frequencies they rely on are protected under <a href="https://www.itu.int/rec/R-REC-RA.769-2-200305-I/en">international agreements</a> but are also under threat from radio interference. </p>
<p>A recent study showed that a large fraction of NASA’s soil moisture measurements <a href="https://doi.org/10.1109/TGRS.2013.2281266">experience interference</a> from ground-based radar systems and consumer electronics. There are systems in place to <a href="https://salinity.oceansciences.org/smap-radiometer.htm">monitor and account for the interference</a>, but avoiding the problem altogether through international communication and prelaunch testing would be a better option for astronomy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A number of satellite dishes in a remote desert." src="https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.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">Most radio telescopes, like the Atacama Large Millimeter Array in Chile, are in areas far from any source of interference. But a new site designed to test technologies and interference solutions could prevent future problems.</span>
<span class="attribution"><a class="source" href="http://www.eso.org/public/images/potw1111a/">ALMA (ESO/NAOJ/NRAO), J. Guarda</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Solutions to a crowded radio spectrum</h2>
<p>As the radio spectrum continues to <a href="https://whyy.org/segments/our-gadgets-increasingly-crowd-the-radio-spectrum-theyre-crowding-out-science-too/">get more crowded</a>, users will have to share. This could involve sharing in time, in space or in frequency. Regardless of the specifics, solutions will need to be tested in a controlled environment. There are early signs of cooperation. The National Science Foundation and SpaceX recently announced an <a href="https://beta.nsf.gov/news/statement-nsf-astronomy-coordination-agreement">astronomy coordination agreement</a> to benefit radio astronomy.</p>
<p>Working with astronomers, engineers, software and wireless specialists, and with the support of the National Science Foundation, we have been <a href="https://www.cs.albany.edu/nrdz-ra/index.html">leading a series of workshops</a> to develop what a national radio dynamic zone could provide. This zone would be similar to existing radio quiet zones, covering a large area with restrictions on radio transmissions nearby. Unlike a quiet zone, the facility would be outfitted with sensitive spectrum monitors that would allow astronomers, satellite companies and technology developers to test receivers and transmitters together at large scales. The goal would be to support creative and cooperative uses of the radio spectrum. For example, a zone established near a radio telescope could test schemes to provide broader bandwidth access for both active uses, like cell towers, and passive uses, like radio telescopes.</p>
<p>For <a href="https://doi.org/10.1109/MCOM.005.2200389">a new paper our team just published</a>, we spoke with users and regulators of the radio spectrum, ranging from radio astronomers to satellite operators. We found that most agreed that a radio dynamic zone could help solve, and potentially avoid, many critical interference issues in the coming decades.</p>
<p>Such a zone doesn’t exist yet, but our team and many people across the U.S. are working to refine the concept so that radio astronomy, Earth-sensing satellites and government and commercial wireless systems can find ways to share the precious natural resource that is the radio spectrum.</p><img src="https://counter.theconversation.com/content/199353/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Gordon De Pree has received funding from National Science Foundation. </span></em></p><p class="fine-print"><em><span>Christopher R. Anderson receives funding from the National Science Foundation, Office of Naval Research, and National Telecommunications and Information Administration. </span></em></p><p class="fine-print"><em><span>Mariya Zheleva receives funding from the National Science Foundation. </span></em></p>Many telescopes use the radio spectrum to learn about the cosmos. Just as human development leads to more light pollution, increasing numbers of satellites are leading to more radio interference.Christopher Gordon De Pree, Deputy Electromagnetic Spectrum Manager, National Radio Astronomy ObservatoryChristopher R. Anderson, Associate Professor of Electrical Engineering, United States Naval AcademyMariya Zheleva, Assistant Professor of Computer Science, University at Albany, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1979052023-01-16T22:13:08Z2023-01-16T22:13:08ZAstronomers reveal the most detailed radio image yet of the Milky Way’s galactic plane<figure><img src="https://images.theconversation.com/files/504592/original/file-20230116-19027-nxt92l.jpg?ixlib=rb-1.1.0&rect=264%2C0%2C1930%2C1103&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Combined images from the ASKAP and Parkes radio telescopes.</span> <span class="attribution"><span class="source">R. Kothes (NRC) and the PEGASUS team</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Two major astronomy research programs, called EMU and PEGASUS, have joined forces to resolve one of the mysteries of our Milky Way: where are all the supernova remnants? </p>
<p>A <a href="https://theconversation.com/a-new-australian-supercomputer-has-already-delivered-a-stunning-supernova-remnant-pic-188375">supernova remnant</a> is an expanding cloud of gas and dust marking the last phase in the life of a star, after it has exploded as a supernova. But the number of supernova remnants we have detected so far with radio telescopes is too low. Models predict five times as many, so where are the missing ones? </p>
<p>We have combined observations from two of Australia’s world-leading radio telescopes, the <a href="https://www.csiro.au/en/about/facilities-collections/ATNF/ASKAP-radio-telescope">ASKAP radio telescope</a> and the <a href="https://www.csiro.au/en/about/facilities-collections/atnf/parkes-radio-telescope">Parkes radio telescope, Murriyang</a>, to answer this question.</p>
<h2>The gas between the stars</h2>
<figure>
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<figcaption>Comparison between the ASKAP/EMU image and the combined ASKAP/EMU plus Parkes/PEGASUS image. <br>Images: R. Kothes (NRC) and E. Carretti (INAF).</figcaption>
</figure>
<p>The new image reveals thin tendrils and clumpy clouds associated with hydrogen gas filling the space between the stars. We can see sites where new stars are forming, as well as supernova remnants.</p>
<p>In just this small patch, only about 1% of the whole Milky Way, we have discovered more than 20 new possible supernova remnants where only seven were previously known. </p>
<p>These discoveries were led by PhD student Brianna Ball from Canada’s University of Alberta, working with her supervisor, Roland Kothes of the National Research Council of Canada, who prepared the image. These new discoveries suggest we are close to accounting for the missing remnants.</p>
<p>So why can we see them now when we couldn’t before?</p>
<figure class="align-center ">
<img alt="The ASKAP radio telescope, showing radio dishes pointed at a blue sky with the sun in the background." src="https://images.theconversation.com/files/504590/original/file-20230116-18-23rt6s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504590/original/file-20230116-18-23rt6s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504590/original/file-20230116-18-23rt6s.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504590/original/file-20230116-18-23rt6s.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504590/original/file-20230116-18-23rt6s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504590/original/file-20230116-18-23rt6s.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504590/original/file-20230116-18-23rt6s.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The ASKAP radio telescope at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory in Western Australia.</span>
<span class="attribution"><span class="source">CSIRO</span></span>
</figcaption>
</figure>
<h2>The power of joining forces</h2>
<p>I lead the <a href="http://www.emu-survey.org/">Evolutionary Map of the Universe</a> or EMU program, an ambitious project with ASKAP to make the best radio atlas of the Southern Hemisphere.</p>
<p>EMU will measure about 40 million new distant galaxies and supermassive black holes, to help us understand how galaxies have changed over the history of the universe.</p>
<p>Early EMU data have already led to the discovery of <a href="https://theconversation.com/odd-radio-circles-that-baffled-astronomers-are-likely-explosions-from-distant-galaxies-178290">odd radio circles (or “ORCs”)</a>, and revealed <a href="https://theconversation.com/dancing-ghosts-a-new-deeper-scan-of-the-sky-throws-up-surprises-for-astronomers-165239">rare oddities like the “Dancing Ghosts”</a>.</p>
<p>For any telescope, the resolution of its images depends on the size of its aperture. Interferometers like ASKAP simulate the aperture of a much larger telescope. With 36 relatively small dishes (each 12m in diameter) but a 6km distance connecting the farthest of these, ASKAP mimics a single telescope with a 6km wide dish.</p>
<p>That gives ASKAP a good resolution, but comes at the expense of missing radio emission on the largest scales. In the comparison above, the ASKAP image alone appears too skeletal.</p>
<figure class="align-center ">
<img alt="The Parkes radio telescope, Murriyang, showing the 64 telescope dish." src="https://images.theconversation.com/files/504591/original/file-20230116-16-v7ugns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504591/original/file-20230116-16-v7ugns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504591/original/file-20230116-16-v7ugns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504591/original/file-20230116-16-v7ugns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504591/original/file-20230116-16-v7ugns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504591/original/file-20230116-16-v7ugns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504591/original/file-20230116-16-v7ugns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Parkes radio telescope, Murriyang.</span>
<span class="attribution"><span class="source">CSIRO</span></span>
</figcaption>
</figure>
<p>To recover that missing information, we turned to a companion project called PEGASUS, led by Ettore Carretti of Italy’s National Institute of Astrophysics.</p>
<p>PEGASUS uses the 64m diameter Parkes/Murriyang telescope – one of the largest single-dish radio telescopes in the world – to map the sky.</p>
<p>Even with such a large dish, Parkes has rather limited resolution. By combining the information from both Parkes and ASKAP, each fills in the gaps of the other to give us the best fidelity image of this region of our Milky Way galaxy. This combination reveals the radio emission on all scales to help uncover the missing supernova remnants.</p>
<p>Linking the datasets from EMU and PEGASUS will allow us to reveal more hidden gems. In the next few years we will have an unprecedented view of almost the entire Milky Way, about a hundred times larger than this initial image, but with the same level of detail and sensitivity.</p>
<p>We estimate there may be up to 1,500 or more new supernova remnants yet to discover. Solving the puzzle of these missing remnants will open new windows into the history of our Milky Way.</p>
<hr>
<p><em>ASKAP and Parkes are owned and operated by CSIRO, Australia’s national science agency, as part of the Australia Telescope National Facility. CSIRO acknowledge the Wajarri Yamaji people as the Traditional Owners and native title holders of Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory, where ASKAP is located, and the Wiradjuri people as the traditional owners of the Parkes Observatory.</em></p><img src="https://counter.theconversation.com/content/197905/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Hopkins 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>Our galaxy should be full of traces of dead stars. Until now, we have found surprisingly few of these supernova remnants, but a new telescope collaboration is changing that.Andrew Hopkins, Professor of Astronomy, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1910542022-10-21T12:38:07Z2022-10-21T12:38:07ZSignatures of alien technology could be how humanity first finds extraterrestrial life<figure><img src="https://images.theconversation.com/files/490943/original/file-20221020-21-mv2tjy.jpg?ixlib=rb-1.1.0&rect=80%2C477%2C3753%2C1678&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Astronomers have been looking for radio waves sent by a distant civilization for more than 60 years.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/illustration-of-signal-coming-out-the-deep-cosmos-royalty-free-image/1338115983?phrase=signal%20coming%20from%20planet%20space&adppopup=true">Rytis Bernotas/iStock via Getty Images</a></span></figcaption></figure><p>If an alien were to look at Earth, many human technologies – from cell towers to fluorescent light bulbs – could be a beacon signifying the presence of life. </p>
<p><a href="https://sites.psu.edu/macyhuston/">We are</a> two <a href="https://sites.psu.edu/astrowright">astronomers</a> <a href="https://scholar.google.com/citations?user=lEUxaaIAAAAJ&hl=en&oi=ao">who</a> work on the <a href="https://www.pseti.psu.edu/about/">search for extraterrestrial intelligence</a> – or SETI. In our research, we try to characterize and detect signs of technology originating from beyond Earth. These are called technosignatures. While scanning the sky for a TV broadcast of some extraterrestrial Olympics may sound straightforward, searching for signs of distant, advanced civilizations is a much more nuanced and difficult task than it might seem.</p>
<h2>Saying ‘hello’ with radios and lasers</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/490923/original/file-20221020-1663-tvwgzj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A laser shooting up from an observatory into a starry sky." src="https://images.theconversation.com/files/490923/original/file-20221020-1663-tvwgzj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/490923/original/file-20221020-1663-tvwgzj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=902&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490923/original/file-20221020-1663-tvwgzj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=902&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490923/original/file-20221020-1663-tvwgzj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=902&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490923/original/file-20221020-1663-tvwgzj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1133&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490923/original/file-20221020-1663-tvwgzj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1133&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490923/original/file-20221020-1663-tvwgzj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1133&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 laser – like the one seen here – or beam of radio waves pointed intentionally at Earth would be a strong sign of extraterrestrial life.</span>
<span class="attribution"><a class="source" href="http://www.eso.org/public/images/gerd_huedepohl_4/">G. Hüdepohl/ESO</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The modern scientific <a href="https://astrobites.org/2021/08/16/classic-paper-summary/">search for extraterrestrial intelligence began in 1959</a> when astronomers Giuseppe Cocconi and Philip Morrison showed that radio transmissions from Earth <a href="https://doi.org/10.4159/harvard.9780674366688.c9">could be detected</a> by radio telescopes at interstellar distances. The same year, <a href="https://theconversation.com/frank-drake-has-passed-away-but-his-equation-for-alien-intelligence-is-more-important-than-ever-189935">Frank Drake</a>, launched the first SETI search, <a href="https://www.seti.org/project-ozma">Project Ozma</a>, by pointing a large radio telescope at two nearby Sun-like stars to see if he could detect any radio signals coming from them. Following the invention of the laser in 1960, astronomers showed that visible light could also <a href="https://doi.org/10.1038/190205a0">be detected from distant planets</a>.</p>
<p>These first, foundational attempts to detect <a href="http://www.bigear.org/oldseti.htm">radio</a> or <a href="https://doi.org/110.1086/423300">laser</a> signals from another civilization were all looking for focused, powerful signals that would have been intentionally sent to the solar system and meant to be found. </p>
<p>Given the technological limitations of the 1960s, astronomers did not give serious thought to searching for broadcast signals – like television and radio broadcasts on Earth – that would leak into space. But a beam of a radio signal, with all of its power focused towards Earth, could be detectable from much farther away – just picture the difference between a laser and a weak light bulb.</p>
<p>The search for intentional radio and laser signals is still one of the most popular SETI strategies today. However, this approach <a href="https://www.universetoday.com/149513/beyond-fermis-paradox-xvii-what-is-the-seti-paradox-hypothesis/">assumes that extraterrestrial civilizations want to communicate</a> with other technologically advanced life. Humans very rarely send targeted signals into space, and some scholars argue that intelligent species may <a href="https://theconversation.com/blasting-out-earths-location-with-the-hope-of-reaching-aliens-is-a-controversial-idea-two-teams-of-scientists-are-doing-it-anyway-182036">purposefully avoid broadcasting out their locations</a>. This search for signals that no one may be sending is called <a href="https://doi.org/10.48550/arXiv.physics/0611283">the SETI Paradox</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490932/original/file-20221020-1690-8mwnqz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An aerial view of a desert with a huge number of satellite dishes." src="https://images.theconversation.com/files/490932/original/file-20221020-1690-8mwnqz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490932/original/file-20221020-1690-8mwnqz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=328&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490932/original/file-20221020-1690-8mwnqz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=328&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490932/original/file-20221020-1690-8mwnqz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=328&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490932/original/file-20221020-1690-8mwnqz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=412&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490932/original/file-20221020-1690-8mwnqz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=412&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490932/original/file-20221020-1690-8mwnqz.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">This artist’s impression shows the Square Kilometer Array, a telescope array currently being built in both Australia and Africa that will be sensitive enough to detect the equivalent of radio broadcasts from distant planets.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:SKA_overview.jpg#/media/File:SKA_overview.jpg">SPDO/TDP/DRAO/Swinburne Astronomy Productions/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Leaking radio waves</h2>
<p>Though humans don’t transmit many intentional signals out to the cosmos, many technologies people use today produce a lot of radio transmissions that leak into space. Some of these signals would be detectable if they came from a nearby star.</p>
<p>The worldwide network of television towers constantly emits signals in many directions that leak into space and can <a href="https://doi.org/10.1126/science.199.4327.377">accumulate into a detectable, though relatively faint</a>, radio signal. Research is ongoing as to whether current emissions from cell towers in the radio frequency on Earth would be detectable using today’s telescopes, but the upcoming <a href="https://doi.org/10.1088/1475-7516/2007/01/020">Square Kilometer Array radio telescope will be able to detect</a> even fainter radio signals with <a href="https://theconversation.com/the-science-behind-the-square-kilometre-array-40870">50 times the sensitivity of current radio telescope arrays</a>. </p>
<p>Not all human-made signals are so unfocused, though. Astronomers and space agencies use beams of radio waves to communicate with <a href="https://www.nasa.gov/directorates/heo/scan/services/networks/deep_space_network/about">satellites and space craft</a> in the solar system. Some researchers also use radio waves for <a href="https://www.nasa.gov/feature/jpl/planetary-radar-observes-1000th-near-earth-asteroid-since-1968">radar to study asteroids</a>. In both of these cases, the radio signals are more focused and pointed out into space. Any extraterrestrial civilization that happened to be in the line of sight of these beams could likely detect these unambiguously artificial signals.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490926/original/file-20221020-18-l76626.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A rendering of a massive set of rings around a star in space." src="https://images.theconversation.com/files/490926/original/file-20221020-18-l76626.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490926/original/file-20221020-18-l76626.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490926/original/file-20221020-18-l76626.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490926/original/file-20221020-18-l76626.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490926/original/file-20221020-18-l76626.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490926/original/file-20221020-18-l76626.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490926/original/file-20221020-18-l76626.png?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">A Dyson Sphere is a theoretical megastructure that would surround a star and collect its light to use as energy.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/kevinmgill/29401385502/">Kevin Gill/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Finding megastructures</h2>
<p>Aside from finding an actual alien spacecraft, radio waves are the most common technosignatures featured in sci-fi movies and books. But they are not the only signals that could be out there.</p>
<p>In 1960, astronomer Freeman Dyson theorized that, since stars are by far the most powerful energy source in any planetary system, a technologically advanced civilization might <a href="https://doi.org/10.1088/10.1126/science.131.3414.1667">collect a significant portion of the star’s light as energy</a> with what would essentially be a massive solar panel. Many astronomers call these megastructures, and there are a few ways to detect them.</p>
<p>After using the energy in the captured light, the technology of an advanced society would <a href="https://stem.guide/topic/entropy-the-second-law-of-thermodynamics/">re-emit some of the energy as heat</a>. Astronomers have shown that this heat <a href="https://ui.adsabs.harvard.edu/abs/1966ApJ...144.1216S/abstract">could be detectable</a> as extra infrared radiation coming from a star system.</p>
<p>Another possible way to find a megastructure would be to <a href="https://theconversation.com/what-are-the-odds-of-an-alien-megastructure-blocking-light-from-a-distant-star-49311">measure its dimming effect on a star</a>. Specifically, large artificial satellites orbiting a star would periodically block some of its light. This would appear as dips in the star’s apparent brightness over time. Astronomers could detect this effect similarly to how <a href="https://theconversation.com/are-there-any-planets-outside-of-our-solar-system-164062">distant planets are discovered today</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/490924/original/file-20221020-13-90h06v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An artist's depiction of a planet covered in cities and with a chemically altered atmosphere." src="https://images.theconversation.com/files/490924/original/file-20221020-13-90h06v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490924/original/file-20221020-13-90h06v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=495&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490924/original/file-20221020-13-90h06v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=495&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490924/original/file-20221020-13-90h06v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=495&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490924/original/file-20221020-13-90h06v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=622&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490924/original/file-20221020-13-90h06v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=622&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490924/original/file-20221020-13-90h06v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=622&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Advanced civilizations may produce a lot of pollution in the form of chemicals, light and heat that can be detected across the vast distances of space.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/press-release/goddard/2021/technosignature">NASA/Jay Freidlander</a></span>
</figcaption>
</figure>
<h2>A whole lot of pollution</h2>
<p>Another technosignature that astronomers have thought about is pollution.</p>
<p>Chemical pollutants – like <a href="https://www.nasa.gov/press-release/goddard/2021/technosignature">nitrogen dioxide</a> and <a href="https://doi.org/10.3847/PSJ/ac5404">chlorofluorocarbons</a> on Earth are almost exclusively produced by human industry. It is possible to detect these molecules in the <a href="https://theconversation.com/its-all-in-the-atmosphere-exploring-planets-orbiting-distant-stars-62034">atmospheres of exoplanets</a> with the same method the James Webb Space Telescope is using to <a href="https://theconversation.com/to-search-for-alien-life-astronomers-will-look-for-clues-in-the-atmospheres-of-distant-planets-and-the-james-webb-space-telescope-just-proved-its-possible-to-do-so-184828">search distant planets for signs of biology</a>. If astronomers find a planet with an atmosphere filled with chemicals that can only be produced by technology, it may be a sign of life.</p>
<p>Finally, <a href="https://doi.org/10.1093/mnras/stac469">artificial light</a> or <a href="https://doi.org/10.1017/S1473550414000585">heat from cities and industry</a> could also be detectable with large optical and infrared telescopes, as would a large <a href="https://doi.org/10.3847/1538-4357/aaae66">number of satellites orbiting a planet</a>. But a civilization would need to produce far more heat, light and satellites than Earth does to be detectable across the vastness of space using technology humans currently possess.</p>
<h2>Which signal is best?</h2>
<p>No astronomer has ever found a confirmed technosignature, so it’s hard to say what will be the first sign of alien civilizations. While many astronomers have thought a lot about <a href="https://doi.org/10.1017/S1473550419000284">what might make for a good signal</a>,
ultimately, nobody knows what extraterrestrial technology might look like and what signals are out there in the Universe. </p>
<p>Some astronomers support a <a href="https://www.aspbooks.org/publications/213/519.pdf">generalized SETI</a> approach which searches for anything in space that current scientific knowledge cannot naturally explain. Some, like us, continue to search for both intentional and unintentional technosignatures. The bottom line is that there are many avenues for detecting distant life. Since no one knows what approach is likely to succeed first, there is still a lot of exciting work left to do.</p><img src="https://counter.theconversation.com/content/191054/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Wright does research supported by the Penn State Extraterrestrial Intelligence Center. He also does SETI research and runs conferences dedicated to SETI with funds from NASA and the NSF.</span></em></p><p class="fine-print"><em><span>Macy Huston does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The technology of an advanced alien civilization is likely to produce many signs that could be detected across the vastness of space. Two astronomers explain the search for technosignatures.Macy Huston, PhD Candidate in Astronomy and Astrophysics, Penn StateJason Wright, Professor of Astronomy and Astrophysics, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1846342022-06-09T17:52:30Z2022-06-09T17:52:30ZNewly discovered fast radio burst challenges what astronomers know about these powerful astronomical phenomena<figure><img src="https://images.theconversation.com/files/467838/original/file-20220608-26-hzbdb2.jpg?ixlib=rb-1.1.0&rect=8%2C866%2C4934%2C2834&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers used a radio telescope in New Mexico to study a particularly interesting fast radio burst.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/dianasch/42831352202/in/photolist-28fRSMG-28eqRCT-2gij1gb-2mVkLCk-abPXeJ-mRBnWr-2nkk1HD-2mWEmz2-2meNv1Y-2mKaj3K-pC9Hhu-2mNuVQQ-56Jkta-2hu7JgN-2mZzZB8-BEVAUW-2mVoTaz-2mchThN-91rSYo-HHErwp-8eN6V4-abWktE-91oF7D-56JkqV-nZDA8K-DqoFyV-2jHHg2U-2juVMX6-of7i5L-2mtzGHF-2i9UMm7-T7hgaw-U7eWMd-2dNEVuC-2dugTrK-EEHmKy-2k5Jwdx-91rQbs-Ng5UdL-2kWVQh1-8snpug-UGDS2z-TBNsWE-6dRTJN-91rRzA-2aPaFTm-2kqAXBQ-TEHUBt-UDLB6b-2kNjNMS/">Diana Robinson/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em> </p>
<h2>The big idea</h2>
<p>A newly discovered fast radio burst has some unique properties that are simultaneously giving astronomers important clues into what may cause these mysterious astronomical phenomena while also calling into question one of the few things scientists thought they knew about these powerful flares, as my colleagues and I describe in a <a href="https://doi.org/10.1038/s41586-022-04755-5">new study</a> in Nature on June 8, 2022.</p>
<p>Fast radio bursts, or FRBs, are extremely bright pulses of radio waves that come from faraway galaxies. They release as much energy in a millisecond as <a href="https://theconversation.com/535-new-fast-radio-bursts-help-answer-deep-questions-about-the-universe-and-shed-light-on-these-mysterious-cosmic-events-161976">the Sun does over many days</a>. Researchers here at West Virginia University <a href="https://doi.org/10.1126/science.1147532">detected the first FRB back in 2007</a>. In the past 15 years, astronomers have detected around 800 FRBs, with <a href="https://doi.org/10.1007/s00159-019-0116-6">more being discovered every day</a>.</p>
<p>When a telescope captures an FRB, one of the most important features researchers look at is something called dispersion. Dispersion is basically a measure of how stretched out an FRB is when it reaches Earth. </p>
<p>The plasma that lies between stars and galaxies causes all light – including radio waves – to slow down, but lower frequencies feel this effect more strongly and slow down more than higher frequencies. FRBs contain a range of frequencies, so the higher frequency light in the burst hits Earth before the lower frequencies, causing the dispersion. This allows researchers to <a href="https://theconversation.com/535-new-fast-radio-bursts-help-answer-deep-questions-about-the-universe-and-shed-light-on-these-mysterious-cosmic-events-161976">use dispersion to estimate how far from Earth an FRB originated</a>. The more stretched out an FRB is, the more plasma the signal must have passed through, the farther away the source must be.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/467844/original/file-20220608-12-p4fex4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram with six panels each showing a spike in a squiggly line and a shaded frequency diagram." src="https://images.theconversation.com/files/467844/original/file-20220608-12-p4fex4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467844/original/file-20220608-12-p4fex4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=190&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467844/original/file-20220608-12-p4fex4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=190&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467844/original/file-20220608-12-p4fex4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=190&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467844/original/file-20220608-12-p4fex4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=238&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467844/original/file-20220608-12-p4fex4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=238&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467844/original/file-20220608-12-p4fex4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=238&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 top of this diagram show six spikes in radio wave brightness that are six bursts from FRB190520. The bottom half shows the frequency range for each individual burst.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s41586-022-04755-5">Niu, CH., Aggarwal, K., Li, D. et al.</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Why it matters</h2>
<p>The new FRB my colleagues and I discovered <a href="https://doi.org/10.1038/s41586-022-04755-5">is named FRB190520</a>. We found it using the <a href="https://doi.org/10.1007/s11433-006-0129-9">Five-hundred-meter Aperture Spherical Telescope</a> in China. An immediately apparent interesting thing about FRB190520 was that it is one of the only 24 repeating FRBs and repeats much more frequently than others – producing 75 bursts over a span of six months in 2020.</p>
<p>Our team then used the <a href="https://public.nrao.edu/telescopes/VLA/">Very Large Array</a>, a radio telescope in New Mexico, to further study this FRB and successfully pinpointed the location of its source – a dwarf galaxy roughly 3 billion light years from Earth. It was then that we started to realize how truly unique and important this FRB is. </p>
<p>First, we found that <a href="https://doi.org/10.1038/s41586-022-04755-5">there is a persistent, though much fainter, radio signal being emitted</a> by something from the same place that FRB190520 came from. Of the more than <a href="https://theconversation.com/535-new-fast-radio-bursts-help-answer-deep-questions-about-the-universe-and-shed-light-on-these-mysterious-cosmic-events-161976">800 FRBs discovered to date</a>, only one other has a similar persistent radio signal.</p>
<p>Second, since we were able to pinpoint that the FRB came from a dwarf galaxy, we were able to determine exactly how far away that galaxy is from Earth. But this result didn’t make sense. Much to our surprise, the distance estimate we made using the dispersion of the FRB was 30 billion light years from Earth, <a href="https://doi.org/10.1038/s41586-022-04755-5">a distance 10 times larger than the actual 3 billion light years to the galaxy</a>. </p>
<p>Astronomers have only been able to pinpoint the exact location – and therefore distance from Earth – <a href="http://frbhosts.org/#explore">of 19 other FRB sources</a>. For the rest of the roughly 800 known FRBs, astronomers have to rely on dispersion alone to estimate their distance from Earth. For the other 19 FRBs with known locations, the distances estimated from dispersion are very similar to the real distances to their source galaxies. But this new FRB shows that estimates using dispersion can sometimes be incorrect and throws many assumptions out the window.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/467843/original/file-20220608-12043-zp6ve6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An image showing distant bright spots of stars and galaxies." src="https://images.theconversation.com/files/467843/original/file-20220608-12043-zp6ve6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/467843/original/file-20220608-12043-zp6ve6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=597&fit=crop&dpr=1 600w, https://images.theconversation.com/files/467843/original/file-20220608-12043-zp6ve6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=597&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/467843/original/file-20220608-12043-zp6ve6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=597&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/467843/original/file-20220608-12043-zp6ve6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=750&fit=crop&dpr=1 754w, https://images.theconversation.com/files/467843/original/file-20220608-12043-zp6ve6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=750&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/467843/original/file-20220608-12043-zp6ve6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=750&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">FRB190520 came from a small dwarf galaxy 3 billion light years away, marked by the cross hairs in the larger inset with the exact location of the FRB source in the circle in the smaller image.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s41586-022-04755-5">Niu, CH., Aggarwal, K., Li, D. et al.</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>What still isn’t known</h2>
<p>Astronomers in this <a href="https://doi.org/10.1007/s00159-019-0116-6">new field</a> still don’t know <a href="https://frbtheorycat.org/index.php/Main_Page">what exactly produces FRBs</a>, so every new discovery or piece of information is important.</p>
<p>Our new discovery raises specific questions, including whether persistent radio signals are common, what conditions produce them and whether the same phenomenon that produces FRBs is responsible for emitting the persistent radio signal. </p>
<p>And a huge mystery is why the dispersion of FRB190520 was so much greater than it should be. Was it due to something near the FRB? Was it related to the persistent radio source? Does it have to do with the matter in the galaxy where this FRB comes from? All of these questions are unanswered.</p>
<h2>What’s next</h2>
<p>My colleagues are going to focus in on studying FRB190520 using a host of different telescopes around the world. By studying the FRB, its galaxy and the space environment surrounding its source, we are hoping to find answers to many of the mysteries it revealed.</p>
<p>More answers will come from other FRB discoveries in the coming years, too. The more FRBs astronomers catalog, the greater the chances of discovering FRBs with interesting properties that can help complete the puzzle of these fascinating astronomical phenomena.</p><img src="https://counter.theconversation.com/content/184634/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kshitij Aggarwal does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Astronomers studying fast radio bursts recently discovered one that repeats, has a persistent radio signal and originated in a galaxy much closer than it should have.Kshitij Aggarwal, Affiliate Researcher in Astronomy and Astrophysics, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1832482022-05-19T13:08:31Z2022-05-19T13:08:31ZHow visionary scientist Bernie Fanaroff put African astronomy on the map<figure><img src="https://images.theconversation.com/files/463595/original/file-20220517-6201-dk0n1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Without Dr Bernie Fanaroff, the SKA might never have come to South African shores</span> <span class="attribution"><span class="source">Foto24/Gallo Images/Getty Images</span></span></figcaption></figure><p>Recent decades have seen remarkable growth in astronomy on the African continent. Africa enjoys pristine dark skies and vast radio quiet zones, making it the ideal home for many advanced telescopes trained on our galaxy and beyond.</p>
<p>For instance, Namibia hosts the <a href="https://www.mpi-hd.mpg.de/hfm/HESS/">High Energy Spectroscopic System</a> (HESS), which is an impressive gamma-ray telescope. The <a href="https://www.salt.ac.za/">Southern African Large Telescope</a> (SALT) in the small South African town of Sutherland is the largest optical telescope in the southern hemisphere. The <a href="https://www.sarao.ac.za/science/meerkat/">MeerKAT</a> telescope in South Africa’s arid and sparsely populated Karoo region is one of the world’s most powerful radio telescopes. It is also one of the precursor telescopes that have been built in preparation for an almighty radio telescope called the <a href="https://www.skatelescope.org/">Square Kilometre Array</a> (SKA).</p>
<p>The SKA is an international mega-science project. Part of it will be built in South Africa and will incorporate MeerKAT. The other part will be built in Western Australia. Construction of the SKA is expected to begin this year.</p>
<p>Through these and other projects, Africa is beginning to emerge as a world leader in astronomy. Many brilliant scientists contribute to this status – but without one, Dr Bernie Fanaroff, the SKA might never have come to South African shores. </p>
<p>We are both astronomers and, in March 2019 launched a podcast, <a href="https://thecosmicsavannah.com/">The Cosmic Savannah</a>, to showcase the amazing astronomy and astrophysics coming out of the African continent. When we reached the 50th episode, Bernie was the obvious guest for the landmark occasion.</p>
<p>Who better than Bernie, we thought, to reflect on how the discipline reached this point.</p>
<p><audio preload="metadata" controls="controls" data-duration="3182" data-image="" data-title="Episode 50: Titans of Astronomy" data-size="127308502" data-source="The Cosmic Savannah" data-source-url="https://thecosmicsavannah.com/episode-50-titans-of-astronomy/" data-license="CC BY-NC-ND" data-license-url="http://creativecommons.org/licenses/by-nc-nd/4.0/">
<source src="https://cdn.theconversation.com/audio/2496/050-the-cosmic-savannah-titans-of-astronomy.mp3" type="audio/mpeg">
</audio>
<div class="audio-player-caption">
Episode 50: Titans of Astronomy.
<span class="attribution"><a class="source" rel="nofollow" href="https://thecosmicsavannah.com/episode-50-titans-of-astronomy/">The Cosmic Savannah</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a><span class="download"><span>121 MB</span> <a target="_blank" href="https://cdn.theconversation.com/audio/2496/050-the-cosmic-savannah-titans-of-astronomy.mp3">(download)</a></span></span>
</div></p>
<h2>Globally famous</h2>
<p>Fanaroff is one of the key individuals responsible for the current growth and strength of astronomy in South Africa. He is a world-renowned radio astronomer who, while working on his PhD at Cambridge University in the early 1970s, made a breakthrough <a href="https://ui.adsabs.harvard.edu/abs/1974MNRAS.167P..31F/abstract">discovery</a> about radio galaxies. Radio galaxies contain supermassive black holes at their cores which spew out huge jets of plasma and glow at radio wavelengths.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/discovery-of-two-new-giant-radio-galaxies-offers-fresh-insights-into-the-universe-153457">Discovery of two new giant radio galaxies offers fresh insights into the universe</a>
</strong>
</em>
</p>
<hr>
<p>Bernie and his collaborator, a British astronomer named Julia Riley, were some of the first people to examine high-resolution images of such radio galaxies. They noticed that the luminosity of a radio galaxy was closely related to the shape of the plasma jets. This led to what became known as the “<a href="https://ned.ipac.caltech.edu/level5/Glossary/Essay_fanaroff.html">Fanaroff-Riley</a>” classification system, still used today, in which galaxies are grouped by their “Fanaroff-Riley” type.</p>
<p>But it took decades for Fanaroff to learn that a classification system had been named partly in his honour. He left the field of astronomy shortly after completing his PhD. Incensed by the poor treatment of workers in apartheid South Africa, he joined the National Union of Metalworkers, eventually becoming its national secretary. He later served in Nelson Mandela’s government, beginning in 1994.</p>
<p>Come 2003, he attended an astronomy conference – and discovered he was world famous. He told us:</p>
<blockquote>
<p>One or two people said to me, ‘Are you the Fanaroff of Fanaroff-Riley?’ This was actually news to me. And they said, ‘We thought you were dead! We heard you’d died because nobody’s heard anything of you since, you know, 1974.’ So I said, ‘No, I haven’t died and it is me,’ but it was all a bit of a surprise.</p>
</blockquote>
<p>After this, Fanaroff returned to astronomy: he became the project director for South Africa’s bid to host the Square Kilometre Array Telescope. Both South Africa and Australia were finalists in the bid; in 2012 it was decided by the international SKA consortium that the telescope would be split between both sites.</p>
<h2>A long-term vision</h2>
<p>Fanaroff and his colleague, Professor Justin Jonas, drove the bid. In our interview, he recalled:</p>
<blockquote>
<p>So [Jonas] said, if we’re going to have the world’s largest telescope in South Africa and in Africa, we better develop a community of radio astronomers and engineers who can build it and use it. So we were able to persuade our steering committee that we should start building a precursor.</p>
</blockquote>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/463690/original/file-20220517-20-qzsjhd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463690/original/file-20220517-20-qzsjhd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463690/original/file-20220517-20-qzsjhd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463690/original/file-20220517-20-qzsjhd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463690/original/file-20220517-20-qzsjhd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463690/original/file-20220517-20-qzsjhd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463690/original/file-20220517-20-qzsjhd.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">Some of the dishes that make up the MeerKAT, a precursor to the SKA, in South Africa’s Karoo region.</span>
<span class="attribution"><span class="source">Mujahid Safodien/AFP via Getty Images</span></span>
</figcaption>
</figure>
<p>The project quickly became about more than just science: it also drove human capacity development in South African astronomy. At the time of the SKA bid there were only five or six radio astronomers in the country.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-the-ska-telescope-is-boosting-south-africas-knowledge-economy-96228">How the SKA telescope is boosting South Africa's knowledge economy</a>
</strong>
</em>
</p>
<hr>
<p>He explained: </p>
<blockquote>
<p>“We decided very early on that we had to focus on getting the young people into science and making sure that we could develop them. So we put aside money for grants for undergraduate study in physics and engineering, for postgraduate study, for masters and PhD students, for research fellows.”</p>
</blockquote>
<p>Ultimately, it was this long-term vision which led to Bernie and his team landing the biggest global scientific project in Africa.</p>
<h2>A bright age of astronomy</h2>
<p>Thanks to people like Bernie, the future is bright for African astronomy. His message to young researchers, he said on the podcast, is: </p>
<blockquote>
<p>I think that you’re actually in a golden age of astronomy and I really envy you and the other young people who are coming into astronomy. Now you’ve got the MeerKAT, but you’ll soon have the SKA, which will be a wonderful telescope.</p>
</blockquote>
<p>He added: “You’ll have the (<a href="https://www.jwst.nasa.gov/">James Webb Space Telescope</a>), which will be a revolutionary optical and infrared telescope. You’ve got all the other new telescopes, the <a href="https://elt.eso.org/">Extremely Large Telescope</a> (in Chile), gamma-ray telescopes. And of course, you’ve now got gravitational wave telescopes. So you’re in a golden age where you’re going to be having so many opportunities.”</p><img src="https://counter.theconversation.com/content/183248/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Cunnama receives funding from the National Research Foundation. He is affiliated with the South African Astronomical Observatory</span></em></p><p class="fine-print"><em><span>Jacinta Delhaize received funding from the NRF for a South African Radio Astronomy postdoctoral fellowship 2018-2021.</span></em></p>Fanaroff is one of the key individuals responsible for the current growth and strength of astronomy in South Africa.Daniel Cunnama, Science Engagement Astronomer, South African Astronomical Observatory, South African Astronomical ObservatoryJacinta Delhaize, Lecturer, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1699662021-10-18T14:27:21Z2021-10-18T14:27:21ZSeti: why extraterrestrial intelligence is more likely to be artificial than biological<figure><img src="https://images.theconversation.com/files/426669/original/file-20211015-21-tuqae2.jpg?ixlib=rb-1.1.0&rect=21%2C71%2C4779%2C3541&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Are we listening in vain?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/radio-telescope-view-night-milky-way-250870294">sdecoret/Shutterstock</a></span></figcaption></figure><p>Is there intelligent life elsewhere in the universe? It’s a question that has been debated for centuries, <a href="https://blogs.scientificamerican.com/life-unbounded/the-first-alien/">if not millenia</a>. But it is only recently that we’ve had an actual chance of finding out, with initiatives such as <a href="https://www.seti.org">Seti</a> (Search for Extraterrestrial Intelligence) using radio telescopes to actively listen for radio messages from alien civilisations. </p>
<p>What should we expect to detect if these searches succeed? My suspicion is that it is very unlikely to be little green men – something I speculated about at a talk at a <a href="https://seti.berkeley.edu/listen/">Breakthrough Listen</a> (a Seti project) conference.</p>
<p>Suppose there are other planets where life began and that it followed something like a Darwinian evolution (which needen’t be the case). Even then, it’s highly unlikely that the progression of intelligence and technology would happen at exactly the same pace as on Earth. If it lagged significantly behind, then that planet would plainly reveal no evidence of extraterrestrial life to our radio telescopes. But around a star older than the Sun, life could have had a head start of a billion years or more. </p>
<p>Human technological civilisation only dates back millennia (at most) – and it may be only one or two more centuries before humans, made up of organic materials such as carbon, <a href="https://www.theguardian.com/technology/2019/mar/28/can-we-stop-robots-outsmarting-humanity-artificial-intelligence-singularity">are overtaken or transcended by</a> inorganic intelligence, such as AI. Computer processing power is already increasing exponentially, meaning AI in the future may be able to use vastly more data than it does today. It seems to follow that it could then get exponentially smarter, surpassing human general intelligence. </p>
<p>Perhaps a starting point would be to enhance ourselves with genetic modification in combination with technology – creating cyborgs with partly organic and partly inorganic parts. This could be a transition to fully artificial intelligences.</p>
<p>AI may even be able to evolve, creating better and better versions of itself on a faster-than-Darwinian timescale for billions of years. Organic human-level intelligence would then be just a brief interlude in our “human history” before the machines take over. So if alien intelligence had evolved similarly, we’d be most unlikely to “catch” it in the brief sliver of time when it was still embodied in biological form. If we were to detect extraterrestrial life, it would be far more likely to be electronic than flesh and blood – and it may not even reside on planets.</p>
<p>We must therefore reinterpret <a href="https://theconversation.com/where-is-everybody-doing-the-maths-on-extraterrestrial-life-3390">the Drake equation,</a> which was established in 1960 to estimate the number of civilisations in the Milky Way with which we could potentially communicate. The equation includes various assumptions, such as how many planets there are, but also how long a civilisation is able to release signals into space, estimated to be between 1,000 and 100 million years.</p>
<p>But the lifetime of an organic civilisation may be millennia at most, while its electronic diaspora could continue for billions of years. If we include this in the equation, it seems there may be more civilisations out there than we thought, but that the majority of them would be artificial.</p>
<p>We may even want to rethink the term “alien civilisations”. A “civilisation” connotes a society of individuals. In contrast, extraterrestrials might be a single integrated intelligence.</p>
<h2>Decoding messages</h2>
<p>If Seti succeeded, it would therefore be unlikely to record decodable messages. Instead, it may spot a byproduct (or even a malfunction) of some super complex machine far beyond our comprehension. </p>
<p>Seti focuses on the radio part of the electromagnetic spectrum. But as we have no idea of what’s out there, we should clearly explore all wavebands, including the optical and X-ray parts. Rather than just listening for radio transmission, we should also be alert to other evidence of non-natural phenomena or activity. These include <a href="https://www.space.com/dyson-sphere.html">artificial structures built around stars</a> to absorb their energy (Dyson spheres) or artificially created molecules, such as <a href="https://gml.noaa.gov/hats/publictn/elkins/cfcs.html">chlorofluorocarbons</a> – nontoxic, nonflammable chemicals containing carbon, chlorine, and fluorine – in planet atmospheres. These chemicals are greenhouse gasses that can’t be created by natural processes, meaning they could be a sign of “<a href="https://theconversation.com/a-layer-of-aerogel-could-make-mars-habitable-and-even-enable-life-to-develop-there-but-heres-why-we-should-wait-120330">terraforming</a>” (changing a planet to make it more habitable) or industrial pollution. </p>
<figure class="align-center ">
<img alt="Artist's impression of a Dyson sphere." src="https://images.theconversation.com/files/426881/original/file-20211018-80042-1f7sdg3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/426881/original/file-20211018-80042-1f7sdg3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/426881/original/file-20211018-80042-1f7sdg3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/426881/original/file-20211018-80042-1f7sdg3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/426881/original/file-20211018-80042-1f7sdg3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/426881/original/file-20211018-80042-1f7sdg3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/426881/original/file-20211018-80042-1f7sdg3.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">
<figcaption>
<span class="caption">Advanced extraterrestrials could build Dyson spheres.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/futuristic-scifi-city-on-ring-planet-1928570306">Eduard Muzhevskyi/Shutterstock</a></span>
</figcaption>
</figure>
<p>I’d argue it would even be worth looking for traces of aliens in our own solar system. While we can probably rule out visits by human-like species, there are other possibilities. An extraterrestrial civilisation that had mastered nanotechnology may have transferred its intelligence to tiny machines, for example. It could then invade other worlds, or even asteroid belts, with swarms of microscopic probes.</p>
<p>And even if we did receive a decodable radio message, how could we know what the intention of the super-intelligent sender would be? We have absolutely zero idea – think of the variety of bizarre motives (ideological, financial and religious) that have driven human endeavours in the past. They may be peaceful and inquisitive. Even less obtrusively, they may realise that it’s easier to think at low temperatures – getting far away from any star, or even hibernating for billions of years until it’s cooler. But they could be expansionist – and this seems the expectation of most who’ve thought about the future trajectory of civilisations.</p>
<h2>The future of intelligence</h2>
<p>As the universe evolves, intelligent species may get unfathomably clever.
Just take our own future. Eventually, stellar births and deaths in our galaxy will proceed gradually more slowly, until it gets jolted as the <a href="https://www.skyatnightmagazine.com/space-science/andromeda-milky-way-galaxy-collision/">Milky Way crashes with the Andromeda galaxy </a> in about billion years. The debris of our galaxy, Andromeda and their smaller companions within our local group of galaxies will thereafter clump together into one amorphous galaxy, while distant ones move away from us and eventually disappear. </p>
<p>But our remnant will continue for far longer – time enough, perhaps, for a civilisation to emerge that could be in possession of huge amounts of energy, even harnessing the entire mass of a galaxy.</p>
<p>This may be the culmination of the long-term trend for living systems to gain complexity. At this stage, all the atoms that were once in stars and gas could be transformed into a giant organism of galactic scale. Some science fiction authors envisage stellar-scale engineering to create black holes and <a href="https://theconversation.com/wormholes-may-be-lurking-in-the-universe-and-new-studies-are-proposing-ways-of-finding-them-153020">wormholes</a> – bridges connecting different points in spacetime, in theory providing shortcuts for space travellers. These
concepts are far beyond any technological capability that we can envisage, but not in violation of basic physical laws. </p>
<h2>Are we artificial?</h2>
<p>Post-human intelligences may also be able to build computers with enormous processing power. Humans are already able to model some quite complex phenomenon, such as the climate. More intelligent civilisations, however, may be able to simulate living things – with actual consciousnesses – or even entire worlds or universes.</p>
<figure class="align-center ">
<img alt="Image of a binary code background of matrix green." src="https://images.theconversation.com/files/426882/original/file-20211018-32522-1w0gnk4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/426882/original/file-20211018-32522-1w0gnk4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=340&fit=crop&dpr=1 600w, https://images.theconversation.com/files/426882/original/file-20211018-32522-1w0gnk4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=340&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/426882/original/file-20211018-32522-1w0gnk4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=340&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/426882/original/file-20211018-32522-1w0gnk4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=427&fit=crop&dpr=1 754w, https://images.theconversation.com/files/426882/original/file-20211018-32522-1w0gnk4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=427&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/426882/original/file-20211018-32522-1w0gnk4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=427&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Are we just characters in an alien computer game?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/binary-code-background-abstract-matrix-green-722889532">Mertsaloff/Shutterstock</a></span>
</figcaption>
</figure>
<p>How do we know that we aren’t <a href="https://theconversation.com/elon-musk-says-were-probably-living-in-a-computer-simulation-heres-the-science-60821">living in such a simulation</a> created by technologically superior aliens? Maybe we are no more than a bit of entertainment for some supreme being who is running such a model? Indeed, if life is destined to be able to create technologically advanced civilisations that can make computer programs, there may be more simulated universes our there than real ones out there – making it conceivable that we are in one of them. </p>
<p>This conjecture may sound outlandish, but it is all based on our current understanding of physics and cosmology. We should, however, surely be open-minded about the possibility that there’s much we don’t understand. Perhaps the laws we see and the constants we measure are only “local” and differ in other parts of the universe? That would lead to even more jaw-dropping possibilities. </p>
<p>Ultimately, physical reality could encompass complexities that neither our intellect nor our senses can grasp. Some electronic “brains” may simply have a quite different perception of reality. Nor can we predict or understand their motives. That’s why we can’t assess whether the current radio silence that Seti are experiencing signifies the absence of advanced alien civilisations, or simply their preference.</p>
<p><em>*This article is partly adapted from a speech given by the author at a Breakthrough Listen conference in 2018</em></p><img src="https://counter.theconversation.com/content/169966/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martin Rees 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>Organic human-level intelligence may be just a brief interlude in human history before the machines take over.Martin Rees, Emeritus Professor of Cosmology and Astrophysics, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1543812021-02-11T04:35:53Z2021-02-11T04:35:53ZA brief history: what we know so far about fast radio bursts across the universe<figure><img src="https://images.theconversation.com/files/383653/original/file-20210211-14-1qn1hrd.jpg?ixlib=rb-1.1.0&rect=0%2C25%2C2480%2C1770&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.scienceimage.csiro.au/image/249/parkes-radio-telescope/">CSIRO/John Masterson</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p><a href="https://theconversation.com/au/topics/fast-radio-bursts-6352">Fast radio bursts</a> are one of the great mysteries of the universe. Since their discovery, we have learned a great deal about these intense millisecond-duration pulses.</p>
<p>But we still have much to learn, such as what causes them. </p>
<p>We know the intense bursts originate in galaxies billions of light years away. We have also used these bursts (called <a href="https://astronomy.swin.edu.au/cosmos/F/Fast+Radio+Bursts">FRB</a>s) to <a href="https://theconversation.com/half-the-matter-in-the-universe-was-missing-we-found-it-hiding-in-the-cosmos-138569">find missing matter</a> that couldn’t be found otherwise.</p>
<p>With teams of astronomers around the world racing to understand their enigma, how did we get to where we are now? </p>
<h2>The first burst</h2>
<p>The first FRB was discovered in 2007 by a team led by British-American astronomer <a href="https://physics.wvu.edu/faculty-and-staff/faculty/duncan-lorimer">Duncan Lorimer</a> using <a href="https://blog.csiro.au/parkes-telescope-indigenous-name/">Murriyang</a>, the traditional Indigenous name for the iconic Parkes radio telescope (image, top).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/silence-please-why-radio-astronomers-need-things-quiet-in-the-middle-of-a-wa-desert-118922">Silence please! Why radio astronomers need things quiet in the middle of a WA desert</a>
</strong>
</em>
</p>
<hr>
<p>The team found an incredibly bright pulse — so bright that many astronomers did not believe it to be real. But there was yet more intrigue. </p>
<p>Radio pulses provide a tremendous gift to astronomers. By measuring when a burst arrives at the telescope at different frequencies, astronomers can tell the total amount of gas that it passed through on its journey to Earth.</p>
<figure class="align-center ">
<img alt="A curved graph, starting high top left and curving down low to bottom right." src="https://images.theconversation.com/files/381639/original/file-20210201-19-15wjt3o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381639/original/file-20210201-19-15wjt3o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=366&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381639/original/file-20210201-19-15wjt3o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=366&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381639/original/file-20210201-19-15wjt3o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=366&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381639/original/file-20210201-19-15wjt3o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=459&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381639/original/file-20210201-19-15wjt3o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=459&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381639/original/file-20210201-19-15wjt3o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=459&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A typical Fast Radio Burst. The burst arrives first at high frequencies and is delayed by as much as several seconds at the lower frequencies. This tell-tale curve is what astronomers are looking for.</span>
<span class="attribution"><span class="source">Ryan Shannon and Vikram Ravi</span></span>
</figcaption>
</figure>
<p>The Lorimer burst had travelled through far too much gas to have originated in our galaxy, the Milky Way. The team concluded it came from a galaxy billions of light years away.</p>
<p>To be visible from so far away, whatever produced it must have released an enormous amount of energy. In just a millisecond it released as much energy as our Sun would in 80 years.</p>
<p>Lorimer’s team could only guess which galaxy their FRB had come from. Murriyang can’t pinpoint FRB locations very accurately. It would take several years for another team to make the breakthrough.</p>
<h2>Locating FRBs</h2>
<p>To pinpoint a burst location, we need to detect an FRB with a radio interferometer — an array of antennas spread out over at least a few kilometres.</p>
<p>When signals from the telescopes are combined, they produce an image of an FRB with enough detail not only to see in which galaxy the burst originated, but in some cases to tell where within the galaxy it was produced. </p>
<p>The first FRB localised was from a source that emitted many bursts. The first burst was discovered in 2012 with the giant <a href="http://www.naic.edu/">Arecibo telescope</a> in Puerto Rico.</p>
<p>Subsequent bursts were detected by the <a href="https://public.nrao.edu/telescopes/vla/">Very Large Array</a>, in New Mexico, and found to be coming from a tiny galaxy about 3 billion light years away.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/386907/original/file-20210301-23-1k5kkjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Several dish-shipped antenna in the desert, all pointing up towards the sky in daylight." src="https://images.theconversation.com/files/386907/original/file-20210301-23-1k5kkjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/386907/original/file-20210301-23-1k5kkjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/386907/original/file-20210301-23-1k5kkjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/386907/original/file-20210301-23-1k5kkjz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/386907/original/file-20210301-23-1k5kkjz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/386907/original/file-20210301-23-1k5kkjz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/386907/original/file-20210301-23-1k5kkjz.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">Several of the ASKAP radio telescope antennas in WA.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In 2018, using the Australian Square Kilometre Array Pathfinder Telescope (<a href="https://www.csiro.au/en/Research/Facilities/ATNF/ASKAP">ASKAP</a>) in Western Australia, <a href="https://theconversation.com/how-we-closed-in-on-the-location-of-a-fast-radio-burst-in-a-galaxy-far-far-away-119177">our team identified the second FRB host galaxy</a>.</p>
<p>In stark contrast to the previous galaxy, this galaxy was very ordinary. But our <a href="https://science.sciencemag.org/content/365/6453/565" title="A single fast radio burst localized to a massive galaxy at cosmological distance">published discovery</a> was this month <a href="https://www.aaas.org/news/astronomical-discovery-earns-2020-aaas-newcomb-cleveland-prize">awarded a prize by the American Association for the Advancement of Science</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1359616899945013256"}"></div></p>
<p>Teams including ours have now localised roughly a dozen more bursts from a wide range of galaxies, large and small, young and old. The fact FRBs can come from such a wide range of galaxies remains a puzzle. </p>
<h2>A burst from close to home</h2>
<p>On April 28, 2020, a flurry of X-rays suddenly bashed into the <a href="https://swift.gsfc.nasa.gov/">Swift</a> telescope orbiting Earth.</p>
<p>The satellite telescope dutifully noted the rays had come from a very magnetic and erratic neutron star in our own Milky Way. This star has form: it goes into fits every few years.</p>
<p>Two telescopes, <a href="https://chime-experiment.ca/en">CHIME</a> in Canada and the STARE2 array in the United States, detected a very bright radio burst within milliseconds of the X-rays and in the direction of that star. This demonstrated such neutron stars could be a source of the FRBs we see in galaxies far away.</p>
<p>The simultaneous release of X-rays and radio waves gave astrophysicists important clues to how nature can produce such bright bursts. But we still don’t know for certain if this is the cause of FRBs.</p>
<h2>So what’s next?</h2>
<p>While 2020 was the year of the local FRB, we expect 2021 will be the year of the the far-flung FRB, even further than already observed.</p>
<p>The CHIME telescope has collected by far the largest sample of bursts and is compiling a meticulous catalogue that should be available to other astronomers soon.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-we-closed-in-on-the-location-of-a-fast-radio-burst-in-a-galaxy-far-far-away-119177">How we closed in on the location of a fast radio burst in a galaxy far, far away</a>
</strong>
</em>
</p>
<hr>
<p>A team at Caltech is building an <a href="https://www.deepsynoptic.org/">array</a> specifically dedicated to finding FRBs.</p>
<p>There’s plenty of action in Australia too. We are developing a new burst-detection supercomputer for ASKAP that will find FRBs at a faster rate and find more distant sources.</p>
<p>It will effectively turn ASKAP into a high-speed, high-definition video camera, and make a movie of the universe at 40 trillion pixels per second.</p>
<p>By finding more bursts, and more distant bursts, we will be able to better study and understand what causes these mysteriously intense bursts of energy. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0t0KoVhqz3Y?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">For the localisation of the first ‘one-off’ FRB, our team was awarded the 2020 Newcomb Cleveland Prize from the American Association for the Advancement of Science.</span></figcaption>
</figure><img src="https://counter.theconversation.com/content/154381/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan Shannon receives funding from the Australian Research Council</span></em></p><p class="fine-print"><em><span>Keith Bannister receives funding from CSIRO and the Australian Research Council.</span></em></p>Australian astronomers are part of a prize-winning team that was the first to pinpoint the location of a fast radio burst. But there is much we still don’t know about these mysterious bursts.Ryan Shannon, Associate Professor, Swinburne University of Technology, Swinburne University of TechnologyKeith Bannister, Astronomer, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1534572021-01-18T13:19:03Z2021-01-18T13:19:03ZDiscovery of two new giant radio galaxies offers fresh insights into the universe<figure><img src="https://images.theconversation.com/files/379206/original/file-20210118-17-1ljd4mt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The two giant radio galaxies found with the MeerKAT telescope. In the background is the sky as seen in optical light. Overlaid in red is the radio light from the enormous radio galaxies, as seen by MeerKAT.</span> <span class="attribution"><span class="source">I. Heywood (Oxford/Rhodes/SARAO)</span></span></figcaption></figure><p>Two giant radio galaxies have been discovered with South Africa’s powerful <a href="https://www.sarao.ac.za/science/meerkat/">MeerKAT telescope</a>, located in the Karoo region, a semi-arid area in the south west of the country. Radio galaxies get their name from the fact that they release huge beams, or ‘jets’, of radio light. These happen through the interaction between charged particles and strong magnetic fields related to supermassive black holes at the galaxies’ hearts.</p>
<p>These giant galaxies are much bigger than most of the others in the Universe and are thought to be quite rare. Although millions of radio galaxies are known to exist, only around 800 giants have been found. This population of galaxies was previously hidden from us by radio telescopes’ limitations. But the MeerKAT has allowed new discoveries because it can detect faint, diffuse light which previous telescopes were unable to do.</p>
<p>Our discovery, <a href="https://academic.oup.com/mnras/article/501/3/3833/6034001">published</a> in the Monthly Notices of the Royal Astronomical Society, gives astronomers further clues about how galaxies have changed and evolved throughout cosmic history. It’s also a way to understand how galaxies may continue to change and evolve – and even to work out how old radio galaxies can get.</p>
<p><audio preload="metadata" controls="controls" data-duration="470" data-image="" data-title="How we discovered two new giant radio galaxies" data-size="7585585" data-source="The Conversation Africa - Pasha" data-source-url="" data-license="CC BY-NC-ND" data-license-url="http://creativecommons.org/licenses/by-nc-nd/4.0/">
<source src="https://cdn.theconversation.com/audio/2111/galaxies-final-version.mp3" type="audio/mpeg">
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<div class="audio-player-caption">
How we discovered two new giant radio galaxies.
<span class="attribution"><span class="source">The Conversation Africa - Pasha</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a><span class="download"><span>7.23 MB</span> <a target="_blank" href="https://cdn.theconversation.com/audio/2111/galaxies-final-version.mp3">(download)</a></span></span>
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<p>The giant radio galaxies were spotted in new radio maps of the sky created by one of the most advanced surveys of distant galaxies. The team working on it has included astronomers from around the world including South Africa, the UK, Italy and Australia. Called the International Gigahertz Tiered Extragalactic Exploration (<a href="http://idia.ac.za/mightee/">MIGHTEE</a>) survey, it involves data collected by South Africa’s impressive MeerKAT radio telescope. MeerKAT consists of 64 antennae and dishes, and started <a href="https://theconversation.com/how-were-probing-the-secrets-of-a-giant-black-hole-at-our-galaxys-centre-108181">collecting science data</a> in early 2018. It will ultimately be incorporated into the <a href="https://www.skatelescope.org/">Square Kilometre Array</a>, an intergovernmental radio telescope project spearheaded by Australia and South Africa.</p>
<p>The galaxies in question are several billion light years away. The discovery of enormous jets and lobes in the MIGHTEE map allowed us to confidently identify the objects as giant radio galaxies.</p>
<p>Their discovery means that a clearer understanding of the evolutionary pathways of galaxies is beginning to emerge. This is tantalising evidence that a large population of faint, very extended giant radio galaxies may exist. This may help us understand how radio galaxies become so huge and what sort of havoc supermassive black holes can wreak on their galaxies. </p>
<h2>What’s new</h2>
<p>Many galaxies have supermassive black holes in their midst. When large amounts of interstellar gas start to orbit and fall in towards the black hole, the black hole becomes ‘active’: huge amounts of energy are released from this region of the galaxy. </p>
<p>In some active galaxies, charged particles interact with the strong magnetic fields near the black hole and release huge beams, or ‘jets’, of radio light. The radio jets of these so-called ‘radio galaxies’ can be many times larger than the galaxy itself and can extend vast distances into intergalactic space. Think of them like jets of water from a whale’s blowhole, a thin column extending into a cloudy plume at the end.</p>
<p>We found these giant radio galaxies in a region of sky that’s about four times the area of the full Moon. Based on what we currently know about the density of giant radio galaxies in the sky, the probability of finding two of them in a region this size is extremely small – only 0.0003%. So, it’s possible that giant radio galaxies – those that emit the beams, or jets of light described above – may actually be more common than we previously thought.</p>
<p>These aren’t the first radio galaxies astronomers have discovered. Many hundreds of thousands have already been identified. But only around 800 have radio jets bigger than 700 kilo-parsecs in size, or around 22 times the size of the Milky Way. These truly enormous systems are called ‘giant radio galaxies’.</p>
<p>Our new discoveries are more than 2 Mega-parsecs across: about 6.5 million light years or about 62 times <a href="https://imagine.gsfc.nasa.gov/features/cosmic/milkyway_info.html">the size of the Milky Way</a>. Yet they are fainter than others of the same size. That’s what makes them harder to see. </p>
<h2>Clues</h2>
<p>We suspect that many more galaxies like these should exist, because of the way we think galaxies should grow and change over their lifetimes. And that’s one question we hope this discovery can help to answer: how old are giant radio galaxies and how did they get so enormous?</p>
<p>Now, telescope technology is making it possible to put these and other theories to the test. MeerKAT is the best of its kind in the world because of the telescope’s unprecedented sensitivity to faint and diffuse radio light. This capability is what made it possible for us to detect the giant radio galaxies. We could see features that haven’t been noticed before: large-scale radio jets coming from the central galaxies, as well as fuzzy cloud-like lobes at the end of the jets.</p>
<figure class="align-center ">
<img alt="Two massive satellite dishes are pointed up towards the night sky" src="https://images.theconversation.com/files/379207/original/file-20210118-13-h2vexp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/379207/original/file-20210118-13-h2vexp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=334&fit=crop&dpr=1 600w, https://images.theconversation.com/files/379207/original/file-20210118-13-h2vexp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=334&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/379207/original/file-20210118-13-h2vexp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=334&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/379207/original/file-20210118-13-h2vexp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=420&fit=crop&dpr=1 754w, https://images.theconversation.com/files/379207/original/file-20210118-13-h2vexp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=420&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/379207/original/file-20210118-13-h2vexp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=420&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">South Africa’s MeerKAT telescope.</span>
<span class="attribution"><span class="source">South African Radio Astronomy Observatory (SARAO)</span></span>
</figcaption>
</figure>
<p>The fact that only very few radio galaxies are so gigantic has always been a bit of a mystery. It is thought that the giants are the oldest radio galaxies, which have existed for long enough (several hundred million years) for their radio jets to grow outwards to these enormous sizes. If this is true, then many more giant radio galaxies should exist than are currently known. And that’s important because radio jets can influence the star formation of their host galaxy. Essentially, they might ‘kill’ their galaxy by blowing out all the gas and preventing the formation of new stars.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/radio-galaxies-the-mysterious-secretive-beasts-of-the-universe-64381">Radio galaxies: the mysterious, secretive "beasts" of the Universe</a>
</strong>
</em>
</p>
<hr>
<p>The MIGHTEE survey continues, and we hope to uncover more of these giant galaxies as it progresses. We also expect to find many more with the Square Kilometre Array: construction of this transcontinental telescope is due to start in South Africa and Australia in 2021 and continue until 2027. Science commissioning observations could begin as early as 2023. </p>
<p>The Square Kilometre Array is also expected to reveal larger populations of radio galaxies, revolutionising our understanding of galaxy evolution.</p><img src="https://counter.theconversation.com/content/153457/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jacinta Delhaize receives funding from the South African Radio Astronomy Observatory. </span></em></p>Based on what we currently know about the density of giant radio galaxies in the sky, the probability of finding two of them in this region is extremely small.Jacinta Delhaize, SARAO Postdoctoral Research Fellow, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1189222020-12-22T20:57:01Z2020-12-22T20:57:01ZSilence please! Why radio astronomers need things quiet in the middle of a WA desert<figure><img src="https://images.theconversation.com/files/374698/original/file-20201214-15-1gentz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Panorama of the spectacular night sky over some of the ASKAP antennas at the MRO. </span> <span class="attribution"><span class="source">Credit: Alex Cherney/CSIRO</span>, <span class="license">Author provided</span></span></figcaption></figure><p>A remote outback station about 800km north of Perth in Western Australia is one of the best places in the world to operate telescopes that listen for radio signals from space.</p>
<p>It’s the site of CSIRO’s Murchison Radio-astronomy Observatory (<a href="https://www.csiro.au/en/Research/Astronomy/ASKAP-and-the-Square-Kilometre-Array/MRO">MRO</a>) and is home to three telescopes (and soon a fourth when half of the <a href="https://www.csiro.au/en/Research/Astronomy/ASKAP-and-the-Square-Kilometre-Array/SKA">Square Kilometre Array</a>, the world’s largest radio telescope, is built there). </p>
<p>But it’s important these telescopes don’t pick up any other radio signals generated here on Earth that could interfere with their observations.</p>
<p>That’s why the observatory was set up with strict rules on what can and can’t be used on site.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/282976/original/file-20190707-51273-o8b5yl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two people standing by a sign saying Radio Quiet Zone." src="https://images.theconversation.com/files/282976/original/file-20190707-51273-o8b5yl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/282976/original/file-20190707-51273-o8b5yl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282976/original/file-20190707-51273-o8b5yl.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282976/original/file-20190707-51273-o8b5yl.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282976/original/file-20190707-51273-o8b5yl.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282976/original/file-20190707-51273-o8b5yl.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282976/original/file-20190707-51273-o8b5yl.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">Me (left) and my colleague Carol Wilson at the signs marking the start of the Australian Radio Quiet Zone WA.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Listening to the sky</h2>
<p>One of the radio telescopes is the Australian Square Kilometre Array Pathfinder (<a href="https://www.csiro.au/en/Research/Facilities/ATNF/ASKAP?ref=/CSIRO/Website/Research/Astronomy/ASKAP-and-the-Square-Kilometre-Array/ASKAP">ASKAP</a>) operated by CSIRO. It’s actually an array of 36 individual antennas that work together as one large telescope.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-we-closed-in-on-the-location-of-a-fast-radio-burst-in-a-galaxy-far-far-away-119177">How we closed in on the location of a fast radio burst in a galaxy far, far away</a>
</strong>
</em>
</p>
<hr>
<p>ASKAP can capture high-quality images and <a href="https://theconversation.com/weve-mapped-a-million-previously-undiscovered-galaxies-beyond-the-milky-way-take-the-virtual-tour-here-148442">scan the whole sky</a>, a bit like a wide-angle lens allowing you to see more through a single viewpoint. It has already found a niche as a <a href="https://blog.csiro.au/explosions-in-the-sky-askap-detects-20-new-fast-radio-bursts/">finder</a> and <a href="https://blog.csiro.au/fast-radio-burst-traced-to-a-distant-galaxy/">localiser</a> of fast radio bursts. These are flashes of radio waves in space that last just milliseconds.</p>
<p>The MRO site also hosts the Curtin University-led Murchison Widefield Array (<a href="http://www.mwatelescope.org/">MWA</a>) telescope, which <a href="https://www.washington.edu/news/2020/06/11/epoch-reionization/">has been peering into the universe’s “dark ages”</a> and <a href="https://www.icrar.org/looking-for-ET/">finding no trace of aliens</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307853/original/file-20191219-11919-1qwlqmk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A series of antennas in the desert." src="https://images.theconversation.com/files/307853/original/file-20191219-11919-1qwlqmk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307853/original/file-20191219-11919-1qwlqmk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307853/original/file-20191219-11919-1qwlqmk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307853/original/file-20191219-11919-1qwlqmk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307853/original/file-20191219-11919-1qwlqmk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307853/original/file-20191219-11919-1qwlqmk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307853/original/file-20191219-11919-1qwlqmk.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">Antennas of the Murchison Widefield Array (MWA) low-frequency radio telescope.</span>
<span class="attribution"><span class="source">Dragonfly Media</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The other radio telescope is Arizona State University’s <a href="https://loco.lab.asu.edu/edges/">EDGES</a>, which is looking for signals from the formation of stars and galaxies early in the universe.</p>
<p>These internationally recognised instruments detect mere whispers from space – radio waves that have travelled for billions of light-years before reaching Earth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307854/original/file-20191219-11951-1b77kxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A single piece of equipment in the desert location." src="https://images.theconversation.com/files/307854/original/file-20191219-11951-1b77kxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307854/original/file-20191219-11951-1b77kxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307854/original/file-20191219-11951-1b77kxa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307854/original/file-20191219-11951-1b77kxa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307854/original/file-20191219-11951-1b77kxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307854/original/file-20191219-11951-1b77kxa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307854/original/file-20191219-11951-1b77kxa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Experiment to Detect the Global EoR Signature (EDGES) instrument.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>But their sensitivity exposes them to sources of unwanted radio frequency interference, known as RFI. </p>
<p>RFI can be caused by radio transmitters, such as mobile phones, CB radios or even wi-fi devices. Electrical equipment such as power tools can also be a problem. </p>
<h2>Way outback and beyond</h2>
<p>What makes the Murchison region an ideal operating environment for limiting RFI is the location has minimal human activity or occupancy. The <a href="https://www.murchison.wa.gov.au/">Murchison Shire</a> is the size of a small country but with a population of only 100 people. </p>
<p>The Shire covers an area of 49,500km² — roughly the size of the Netherlands in Europe. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/375288/original/file-20201216-17-uti6wb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map showing the location of the observatory in Western Australia" src="https://images.theconversation.com/files/375288/original/file-20201216-17-uti6wb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375288/original/file-20201216-17-uti6wb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375288/original/file-20201216-17-uti6wb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375288/original/file-20201216-17-uti6wb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375288/original/file-20201216-17-uti6wb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=523&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375288/original/file-20201216-17-uti6wb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=523&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375288/original/file-20201216-17-uti6wb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=523&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The location of the MRO on Boolardy Station in WA.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>With the help of the Commonwealth and Western Australia governments, significant regulatory protection has been established to protect the site.</p>
<p>For example, the Australian Radio Quiet Zone Western Australia (<a href="https://www.atnf.csiro.au/projects/askap/ARQZWA.html">ARQZWA</a>), established by the Australian Communications and Media Authority, created a fixed zone around the MRO site to protect the telescopes from interference. Other groups intending to use transmitting equipment must seek permission first and follow any guidelines given.</p>
<h2>Switch off everything</h2>
<p>When staff go out to the site for the first time they get training about RFI, health and safety and indigenous culture.</p>
<p>Mobile phones need to be turned off at all times (which is fine, because it’s too far from any mobile towers to work anyway). </p>
<p>Bluetooth devices (wireless mice or fitness trackers) should be switched off or left behind, laptops should have Bluetooth and Wi-Fi switched off. The list goes on. </p>
<p>The MRO control building has a double RFI door to enter through – think airlock-style in any sci-fi movie.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/374636/original/file-20201213-23-y8qsun.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="One of the airlock style double doors." src="https://images.theconversation.com/files/374636/original/file-20201213-23-y8qsun.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/374636/original/file-20201213-23-y8qsun.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/374636/original/file-20201213-23-y8qsun.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/374636/original/file-20201213-23-y8qsun.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/374636/original/file-20201213-23-y8qsun.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/374636/original/file-20201213-23-y8qsun.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/374636/original/file-20201213-23-y8qsun.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The twin airlock-style RFI doors at the MRO control building.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The site has a hybrid power station with solar panels that deliver up to 40% of the observatory’s power.</p>
<p>During the day, when the the clean energy system generates more power than the site requires, the excess energy is stored in a 2.5MWh lithium-ion battery, one of the largest in Australia. </p>
<p>The design specifications of the MRO power station ensure the facility contains the RFI generated by its own electronic systems.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307858/original/file-20191219-11900-1g3u2z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The solar panel array in the middle of the desert." src="https://images.theconversation.com/files/307858/original/file-20191219-11900-1g3u2z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307858/original/file-20191219-11900-1g3u2z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307858/original/file-20191219-11900-1g3u2z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307858/original/file-20191219-11900-1g3u2z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307858/original/file-20191219-11900-1g3u2z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307858/original/file-20191219-11900-1g3u2z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307858/original/file-20191219-11900-1g3u2z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aerial view of the MRO power station, which has an array of 5,280 solar panels and battery with RFI shielding.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>You can’t stop everything</h2>
<p>Unfortunately, as with all Earth-based locations, the telescopes receive RFI from orbiting satellites, which fall under international jurisdiction. The site also receives signals from aircraft safety beacons on commercial flights over the region. </p>
<p>Astronomers have developed software to remove this RFI from data as it usually overwhelms any astronomical signals. </p>
<p>We’ve also had several recorded occasions (usually during summer) when radio signals from as far away as Perth have been detected, due to atmospheric ducting. This is where the atmosphere effectively “guides” the radio waves much further than they would normally travel, due to changes in the atmospheric layers. Fortunately this is very rare. </p>
<p>The MRO has been in existence for about ten years, one of the newest such observatories in the world, but the 3,450km² Boolardy pastoral station on which it stands was established back in the 1850s.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307859/original/file-20191219-11914-1c2vkzf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A lizard walking in front of the telescope equipment." src="https://images.theconversation.com/files/307859/original/file-20191219-11914-1c2vkzf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307859/original/file-20191219-11914-1c2vkzf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307859/original/file-20191219-11914-1c2vkzf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307859/original/file-20191219-11914-1c2vkzf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307859/original/file-20191219-11914-1c2vkzf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307859/original/file-20191219-11914-1c2vkzf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307859/original/file-20191219-11914-1c2vkzf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A goanna (or bangara in Wajarri Yamatji language) strolls past some of the antennas.</span>
<span class="attribution"><span class="source">ICRAR/Curtin</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The traditional owners are the Wajarri Yamatji, who have lived in the region for tens of thousands of years. Together we negotiated an Indigenous Land Use Agreement (ILUA) in 2009 for the current telescopes, and we are negotiating a second one to allow the construction of the SKA.</p>
<p>Protection of the indigenous heritage is a significant component of this agreement and a major responsibility for the Australian government, CSIRO and the SKA organisation.</p>
<p>We also work collaboratively with neighbouring pastoralists to ensure they can carry on their daily work, including practices such as mustering, in a way that is compatible with radio astronomy. </p>
<h2>Visitors are not welcome</h2>
<p>Due to the remoteness of the MRO and the radio quiet rules and regulations, even those involved with the projects are discouraged from visiting (I’ve only been to the site once).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/weve-mapped-a-million-previously-undiscovered-galaxies-beyond-the-milky-way-take-the-virtual-tour-here-148442">We've mapped a million previously undiscovered galaxies beyond the Milky Way. Take the virtual tour here.</a>
</strong>
</em>
</p>
<hr>
<p>Tourists are discouraged. We’ve distributed fact sheets to locals and visitor centres to explain this in more detail.</p>
<p>But you can visit the site remotely. We’ve created a cool techy replacement where you can take a <a href="https://virtualtours-external.csiro.au/MRO/">virtual tour of this unique and wondrous place</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/301707/original/file-20191114-26207-m2978q.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A screengrab of the virtual tour of the site." src="https://images.theconversation.com/files/301707/original/file-20191114-26207-m2978q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/301707/original/file-20191114-26207-m2978q.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/301707/original/file-20191114-26207-m2978q.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/301707/original/file-20191114-26207-m2978q.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/301707/original/file-20191114-26207-m2978q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/301707/original/file-20191114-26207-m2978q.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/301707/original/file-20191114-26207-m2978q.png?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">Take a virtual tour of the MRO site.</span>
<span class="attribution"><a class="source" href="https://virtualtours-external.csiro.au/MRO/">CSIRO</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure><img src="https://counter.theconversation.com/content/118922/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kate Chow works for the Commonwealth Scientific and Industrial Research Organisation. </span></em></p>Visitors are discouraged from the remote desert location where powerful telescopes are listening to the universe.Kate Chow, Research Scientist, SKA Site & Infrastructure, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1517342020-12-11T05:40:18Z2020-12-11T05:40:18ZArecibo telescope’s fall is indicative of global divide around funding science infrastructure<figure><img src="https://images.theconversation.com/files/374283/original/file-20201210-24-1ust91j.jpg?ixlib=rb-1.1.0&rect=0%2C16%2C5351%2C3532&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Once featured in movies, TV shows and video games, the Arecibo Observatory was the pride of Puerto Rico.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/this-aerial-view-shows-the-damage-at-the-arecibo-news-photo/1229890426">RICARDO ARDUENGO / Contributor / AFP via Getty Images</a></span></figcaption></figure><p>A mere two weeks after the <a href="https://apnews.com/article/puerto-rico-radio-telescrope-to-close-b63df9ec84a876ab1c2e665f20e402e4">National Science Foundation declared it would close the Arecibo single-dish radio telescope</a> – once the largest in the world – the observatory took a dramatic dying breath and collapsed on Dec. 1, 2020.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Eenw0p14ZrM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Arecibo Observatory Collapse in Puerto Rico.</span></figcaption>
</figure>
<p>While drone footage captured the moment in excruciating detail, in truth, the disintegration of the telescope in Arecibo, Puerto Rico began far before this cinematic end. </p>
<p>It is tempting to blame the demise of Arecibo on the physical damage it sustained earlier in 2020, when an auxiliary metal cable snapped – perhaps a delayed consequence of <a href="https://weather.com/safety/hurricane/news/2020-07-30-tropical-storm-isaias-puerto-rico-dominican-republic-haiti-impacts">Tropical Storm Isaias</a> or the <a href="https://www.cbsnews.com/news/5-0-magnitude-earthquake-hits-southern-puerto-rico-amid-ongoing-tremors-2020-01-25/">earthquakes that shook Puerto Rico</a>. But Arecibo’s downfall was, in reality, caused by years of financial struggles. </p>
<p>As someone who <a href="https://scholar.google.com/citations?user=GGLRwIwAAAAJ&hl=en&oi=ao">studies technology and infrastructure development</a>, I see what happened at Arecibo as a classic example of the tension between facility maintenance and scientific progress.</p>
<h2>From prominence to ruin</h2>
<p>Completed in 1963, Arecibo collected <a href="https://www.naic.edu/ao/legacy-discoveries">data that led to one Nobel Prize</a> and <a href="http://www.naic.edu/ao/blog/arecibo-observatory-contributes-exploration-black-holes-started-year%E2%80%99s-nobel-prize-winners">played a critical role in a second</a>. In 1992, it was the first observatory to spot planets outside Earth’s solar system. In the past decades, it also played a large role in the search for extraterrestrial intelligence, including <a href="https://www.seti.org/seti-institute/project/details/arecibo-message">broadcasting the first terrestrial message to outer space</a>. </p>
<p>But for all its achievements, U.S. commitment to Arecibo began to falter in 2006. The National Science Foundation, which supported Arecibo, implemented a 15% budget cut that year across its Division of Astronomical Sciences. <a href="https://www.nature.com/news/2006/061106/full/061106-4.html">Arecibo was among the first facilities on the chopping block</a>, despite its continued productivity. </p>
<p>The previous year, the NSF had announced it was preparing to reallocate funds between existing facilities <a href="http://www.naic.edu/%7Eastro/NSFSR/Senior%20Review%20Memo%201.pdf">in order to initiate “new activities.”</a> These initiatives included the funding and development of the Atacama Large Millimeter Array in Chile, starting in 2003. </p>
<p>The decision to cut Arecibo’s funding was met with <a href="https://www.chronicle.com/article/astronomers-are-at-odds-over-recommendation-to-scale-down-funds-for-arecibo-telescope/">resistance from the scientific community</a> and beyond, including the then-governor of Puerto Rico, Aníbal Acevedo Vilá, who wrote to the NSF <a href="http://www.naic.edu/%7Eastro/Letter_From_Governor.pdf">requesting reconsideration</a>.</p>
<p>But in 2007 Arecibo’s <a href="https://www.nytimes.com/2007/11/20/science/space/20scop.html">budget was slashed from US$10.5 to $8 million</a>. With a second major cut scheduled for four years later, the closure of the facility seemed imminent. Instead, the NSF tasked a new consortium to take over the management of Arecibo in 2011, changing it from a federally funded institution to one that <a href="https://www.sciencemag.org/news/2011/05/new-consortium-run-arecibo-observatory">could seek funds from other sources</a>. </p>
<p>Optimism about this development soon gave way to pessimism. NSF continued to support Arecibo, <a href="https://www.pbs.org/newshour/science/worlds-largest-radio-telescope-faces-retirement">with NASA pitching in a third of costs</a>. However, the balancing act of a flat NSF budget and the promise of other new observatory projects <a href="https://www.pbs.org/newshour/science/worlds-largest-radio-telescope-faces-retirement">once again threatened the observatory</a>. In 2015, Robert Kerr, then facilities director of Arecibo, <a href="https://doi.org/10.1038/nature.2015.18745">quit – allegedly over funding clashes</a>. In 2018, the <a href="https://www.sciencemag.org/news/2018/02/iconic-arecibo-radio-telescope-saved-university-consortium">University of Central Florida took over management of Arecibo</a> and helped it recover from damages sustained by Hurricane Maria.</p>
<p>But the end was coming. On November 19, 2020, the NSF finally announced the <a href="https://www.nytimes.com/2020/11/19/science/arecibo-observatory.html">official end of operations at the telescope</a>. </p>
<h2>Pride of place</h2>
<p>A community of astronomers and locals are <a href="https://www.dailyherald.com/article/20201201/news/312019967">actively mourning the ruins of Arecibo</a>. Beyond its scientific success, Arecibo signified more.</p>
<p>#WhatAreciboMeansToMe, a hashtag on Twitter, has collected hundreds of stories from locals and tourists, astronomers and enthusiasts alike. Puerto Rican voices are loud here, many recounting childhood memories of hiking up the trail to the Ángel Ramos Visitors’ Center. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1333768301382668290"}"></div></p>
<p>The Arecibo Observatory <a href="https://www.nationalgeographic.com/science/2020/11/historic-radio-telescope-in-puerto-rico-to-be-demolished/">occupied a space of pride for Puerto Rican scientists</a> and the local community. In many ways, it was a symbol of the island. Through this lens, to watch the Arecibo Observatory be allowed to collapse and become rubble is painful for many, especially when contrasted with defunct observatories in the continental United States, where <a href="https://astronomy.williams.edu/hopkins-observatory/other-observatories/">a number are preserved as historical sites</a>.</p>
<p>In Latin America, infrastructure projects are often tied to ideas about economic development – <a href="https://foreignpolicy.com/2009/10/13/the-ideology-of-development/">a potential answer to solve a country’s ills</a>. In this context, to watch a prized facility literally crumble, as the United States retracted its financial involvement, seems like nothing less than abandonment.</p>
<p>It is interesting to note that controversy has often followed the construction of large astronomy facilities. From the Maunakea Observatories being <a href="https://www.forbes.com/sites/alexknapp/2015/06/12/understanding-the-thirty-meter-telescope-controversy/?sh=6948f9ee62af">built on land sacred to native Hawaiians</a> to labor disputes in the <a href="https://www.nature.com/news/alma-observatory-halts-work-amid-labour-dispute-1.13612">building of the Atacama Large Millimeter Array</a> in Chile, to the seizing of lands and racial tensions <a href="https://www.scientificamerican.com/article/in-south-africa-opposition-flares-against-giant-ska-radio-telescope/">surrounding the Square Kilometer Array</a> in the Karoo region of South Africa, a pattern emerges of Northern scientific institutions investing in regions with long colonial histories – and stirring up local concern and discontent. </p>
<p>In the case of Arecibo, these disputes flared at the end rather than at the beginning. But a similar lack of interest in how scientific research facilities fit the place they inhabit is clear. In my view, it is time to begin discussions beyond the scientific importance of research facilities. Planners must address their full life cycles and their impact on local communities.</p><img src="https://counter.theconversation.com/content/151734/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Raquel Velho does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The collapse of the Arecibo Observatory in Puerto Rico was a result of financial neglect – and was a long time coming.Raquel Velho, Assistant Professor of Science and Technology Studies, Rensselaer Polytechnic InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1515102020-12-07T13:08:37Z2020-12-07T13:08:37ZThree scientists on what we learned from the Arecibo radio telescope<figure><img src="https://images.theconversation.com/files/373089/original/file-20201204-23-5mfera.jpg?ixlib=rb-1.1.0&rect=738%2C194%2C4291%2C2952&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Large radio telescope dish in Arecibo national observatory.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/large-radio-telescope-dish-arecibo-national-1263118288">Shutterstock/photospirit</a></span></figcaption></figure><p>Astronomers are mourning the loss of the world’s second largest radio telescope in Puerto Rico. The US National Science Foundation <a href="https://www.bbc.co.uk/news/world-us-canada-55147973">said</a> the Arecibo telescope’s 900-tonne instrument platform fell onto a reflector dish some 450ft (137 metres) below – just weeks after it was announced that the telescope would be dismantled due to safety fears.</p>
<p>It was a sad and dramatic end for this magnificent telescope (once famously scaled <a href="https://www.youtube.com/watch?v=6HFkF8904Uw">by James Bond</a>) which was the largest in the world <a href="https://www.nature.com/articles/d41586-019-02790-3">until 2019</a>. It has given so much to humanity from the start of its observations in <a href="https://www.naic.edu/ao/history">1963</a> and we all have reasons to be grateful and to celebrate. </p>
<p>We are three scientists from different fields. But we all had the good fortune of working with Arecibo in one way or another. Here are our personal perspectives and a brief list of some of its most significant discoveries.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ssHkMWcGat4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>Philippe Blondel – ‘the message’ and Venus</h2>
<p>Surprising as it may seem, I discovered Arecibo thanks to a <a href="https://www.okapi.fr/">French journal</a> for curious children. In a 1974 issue of Okapi, it was explained how radio telescopes were used to listen to stars, to image planets and even to send interstellar radio messages. It was the year the <a href="https://en.wikipedia.org/wiki/Arecibo_message">Arecibo message</a> was broadcast into space.</p>
<p>The message was made up of basic numbers, chemistry, biology and the Earth’s location in 1,679 bits (less than a tweet). It will reach its target star system in 25,000 years – proving, if proof were needed, that Arecibo’s work will live on long after its physical demise.</p>
<p>Arecibo was also the telescope that gave us the first high-resolution <a href="https://astronomynow.com/2015/03/10/venus-revealed-in-high-resolution-radar-images-from-earth/">radar images of Venus</a>. It managed to pierce through the heavy clouds that had always limited the view of traditional optical telescopes. In 1970, it took pictures of the highly reflective Alpha and Beta regions and huge <a href="https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00149">Maxwell Montes</a> mountain chains, 11km high. Then in 1988, by measuring light across several polarisations, Arecibo showed how complex the surface of Earth’s “<a href="https://www.esa.int/ESA_Multimedia/Images/2019/05/Earth_s_evil_twin#:%7E:text=Welcome%20to%20Venus.,and%20a%20sweltering%20470%C2%BAC%20surface.&text=It%20is%20a%20natural%20phenomenon%20that%20helps%20regulate%20a%20planet's%20temperature.">evil twin</a>” (almost the same size but plagued with a poisonous atmosphere of carbon dioxide and a sweltering 470ºC surface) really was. The different terrains were seen in glorious detail and helped prepare and extend the results of the <a href="https://solarsystem.nasa.gov/missions/magellan/in-depth/">Magellan mission</a>.</p>
<figure class="align-center ">
<img alt="Black and white image of venus" src="https://images.theconversation.com/files/373093/original/file-20201204-21-1ojlk37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373093/original/file-20201204-21-1ojlk37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=256&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373093/original/file-20201204-21-1ojlk37.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=256&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373093/original/file-20201204-21-1ojlk37.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=256&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373093/original/file-20201204-21-1ojlk37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=322&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373093/original/file-20201204-21-1ojlk37.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=322&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373093/original/file-20201204-21-1ojlk37.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=322&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Radar image of Venus taken by Arecibo. Many features, including mountain ranges, volcanic domes and craters can be seen.</span>
<span class="attribution"><a class="source" href="https://public.nrao.edu/gallery/arecibo-gbt-image-of-venus-2/">Campbell et al., (NRAO/AUI/NSF); NAIC</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Arecibo revealed how the intricate patterns of geological structures criss-cross to form tesserae (which look similar to parquet floors) that are <a href="https://uapress.arizona.edu/book/venus-ii">unique to Venus</a> and are not seen anywhere else in the solar system.</p>
<h2>Karen Masters – hydrogen</h2>
<p>A new, state-of-the-art seven pixel camera was installed at Arecibo in 2004 while I was completing my PhD in extragalactic radio astronomy. Radio pixels are very big and that camera is the size of a large refrigerator (it definitely won’t fit in your pocket). It was used to, among other things, detect hydrogen. Hydrogen is the most abundant element in the universe and it emits a characteristic radio signal, known as the “<a href="http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/h21.html">21cm line</a>”.</p>
<figure class="align-center ">
<img alt="Woman and baby daughter stand in front of radio telescope." src="https://images.theconversation.com/files/373094/original/file-20201204-19-ahgruw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373094/original/file-20201204-19-ahgruw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373094/original/file-20201204-19-ahgruw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373094/original/file-20201204-19-ahgruw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373094/original/file-20201204-19-ahgruw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373094/original/file-20201204-19-ahgruw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373094/original/file-20201204-19-ahgruw.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">Karen Masters with her baby daughter at the Arecibo radio telescope in 2008.</span>
<span class="attribution"><span class="source">Karen Masters</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Many galaxies have more than enough hydrogen to be detected this way. And a detection means we can also measure how fast these galaxies are rotating and how far away they are. Arecibo’s observations of galaxies in the <a href="https://en.wikipedia.org/wiki/Perseus-Pisces_Supercluster">Pisces-Perseus supercluster</a> won Martha Haynes and Riccardo Giovanelli the <a href="http://www.nasonline.org/programs/awards/henry-draper-medal.html">1989 Henry Draper medal</a> for the first three dimensional map of this massive string like structure of galaxies. </p>
<p>Because Arecibo was so big it could detect the faintest traces of hydrogen in galaxies – the record for the most distant detections <a href="https://academic.oup.com/mnras/article/446/4/3526/2891907">was broken by Arecibo</a> and the Arecibo camera was used to complete <a href="http://egg.astro.cornell.edu/alfalfa/epo/index.php">a survey</a> which discovered numerous, tiny hydrogen-rich galaxies. These discoveries challenged our understanding of how galaxies form. </p>
<h2>Carole Mundell – The dynamic universe</h2>
<p>Although I began my career as a radio astronomer mapping hydrogen in nearby galaxies, my research interests now focus on high energy, time-variable and transient phenomena in the dynamic universe. For me, Arecibo will remain a pioneering and enduring icon in <a href="https://astronomy.ac.uk/msc/timedomain">time-domain</a> astrophysics (the study of how astronomical objects change with time).</p>
<p>From its early work on <a href="https://theconversation.com/uk/topics/pulsars-1324">pulsars</a> to recent breakthroughs in the study of mysterious radio flashes, the telescope has probed fundamental laws of physics and motivated new discoveries with other facilities around the world. </p>
<figure class="align-center ">
<img alt="Colour image of the Crab Nebula" src="https://images.theconversation.com/files/373285/original/file-20201207-23-1mxpjx2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/373285/original/file-20201207-23-1mxpjx2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/373285/original/file-20201207-23-1mxpjx2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/373285/original/file-20201207-23-1mxpjx2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/373285/original/file-20201207-23-1mxpjx2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/373285/original/file-20201207-23-1mxpjx2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/373285/original/file-20201207-23-1mxpjx2.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">A composite image of the Crab Nebula showing the X-ray (blue) and optical (red) images superimposed.</span>
<span class="attribution"><a class="source" href="https://hubblesite.org/contents/media/images/2002/24/1248-Image.html">NASA/CXC/ASU/J. Hester et al</a></span>
</figcaption>
</figure>
<p>Highlights include <a href="https://www.naic.edu/ao/legacy-discoveries">the 1968 discovery</a> of clear evidence of a pulsar with a rotation period of 33 milliseconds in the Crab Nebula (this confirmed earlier suggestions by pulsar pioneer <a href="https://royalsociety.org/people/jocelyn-bell-burnell-11066/">Joceyln Bell Burnell</a> that the nebula appeared to be flashing). And the 1974 discovery of the <a href="https://www.naic.edu/ao/legacy-discoveries">first binary pulsar</a> (pulsars locked in orbit around a common centre of mass). </p>
<p>The measurements, taken by Russell Hulse and Joseph Taylor, confirmed the loss of energy due to gravitational radiation predicted in Einstein’s General Theory of Relativity. They had used the telescope to find a new type of pulsar which opened up new possibilities for the study of gravitation and led to their 1993 <a href="https://www.nobelprize.org/prizes/physics/1993/summary/">Nobel Prize in Physics</a>. </p>
<p>Decades of Arecibo pulsar monitoring data continue to be mined by astronomers and in <a href="https://www.nasa.gov/multimedia/imagegallery/image_feature_574.html">1992 the first exoplanet</a> was discovered around a pulsar. </p>
<p>In 2016, Arecibo discovered the first repeating <a href="https://iopscience.iop.org/article/10.1088/0004-637X/790/2/101">Fast Radio Burst</a> (very short-lived flashes of intense cosmic radio waves). The origin of these bursts is still unknown but is likely lie at cosmic distances beyond our Milky Way galaxy. The Arecibo discovery <a href="https://theconversation.com/message-from-aliens-or-colliding-objects-the-hunt-for-enigmatic-radio-bursts-is-about-to-get-real-55965">heralded a new international race</a> to solve this mystery. </p>
<p>Today, generations of astronomers around the world are grateful to the engineers who realised the dream of the world’s largest radio telescope and ensured it remained a world-leading facility. Arecibo’s discoveries still stand out and its long scientific legacy is secure.</p><img src="https://counter.theconversation.com/content/151510/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Masters is a member of the Committee on Radio Frequencies of the National Academy of Sciences, and on the advisory board for the Green Bank Radio Observatory. </span></em></p><p class="fine-print"><em><span>Carole Mundell and Philippe Blondel do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The Arecibo radio telescope has collapsed but its amazing discoveries will live on.Philippe Blondel, Senior Lecturer, Department of Physics, University of BathCarole Mundell, Professor of Extragalactic Astronomy, Head of the Astrophysics Group, University of BathKaren Masters, Associate Professor of Physics and Astronomy, Haverford CollegeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1484422020-11-30T19:07:33Z2020-11-30T19:07:33ZWe’ve mapped a million previously undiscovered galaxies beyond the Milky Way. Take the virtual tour here.<figure><img src="https://images.theconversation.com/files/371858/original/file-20201130-23-cb0ej8.jpg?ixlib=rb-1.1.0&rect=142%2C0%2C8525%2C3313&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Astronomers have mapped about a million previously undiscovered galaxies beyond the Milky Way, in the most detailed survey of the southern sky ever carried out using radio waves.</p>
<p>The <a href="https://research.csiro.au/racs/">Rapid ASKAP Continuum Survey</a> (or RACS) has placed the CSIRO’s <a href="https://www.csiro.au/en/Research/Facilities/ATNF/ASKAP">Australian SKA Pathfinder</a> radio telescope (ASKAP) firmly on the international astronomy map.</p>
<p>While past surveys have taken years to complete, ASKAP’s RACS survey was conducted in less than two weeks — smashing previous records for speed. Data gathered have produced images five times more sensitive and twice as detailed as previous ones.</p>
<h2>What is radio astronomy?</h2>
<p>Modern astronomy is a multi-wavelength enterprise. What do we mean by this?</p>
<p>Well, most objects in the universe (including humans) emit radiation over a broad spectrum, called the electromagnetic spectrum. This includes both visible and invisible light such as X-rays, ultraviolet light, infrared light and radio waves.</p>
<p>To understand the universe, we need to observe the entire electromagnetic spectrum as each wavelength carries different information. </p>
<p>Radio waves have the longest wavelength of all forms of light. They allow us to study some of the most extreme environments in the universe, from cold clouds of gas to supermassive black holes. </p>
<p>Long wavelengths pass through clouds, dust and the atmosphere with ease, but need to be received with large antennas. Australia’s wide open (but relatively low-altitude) spaces are the perfect place to build large radio telescopes.</p>
<p>We have some of the most spectacular views of the centre of the Milky Way from our position in the Southern Hemisphere. Indigenous astronomers have appreciated this benefit for millennia.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-7809-marcialangton-to-7630-yidumduma-5-asteroids-named-after-aboriginal-and-torres-strait-islander-people-144596">From 7809 Marcialangton to 7630 Yidumduma: 5 asteroids named after Aboriginal and Torres Strait Islander people</a>
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</em>
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<h2>A stellar breakthrough</h2>
<p>Radio astronomy is a <a href="https://public.nrao.edu/radio-astronomy/the-history-of-radio-astronomy/">relatively new field</a> of research, dating back to the 1930s. </p>
<p>The first detailed 30cm radio map of the southern sky — which includes everything a telescope can see from its location in the Southern Hemisphere — was Sydney University’s <a href="http://www.astrop.physics.usyd.edu.au/sumss/">Molonglo Sky Survey</a>. Completed in 2006, this survey took almost a decade to observe 25% of the entire sky and produce final data products. </p>
<p>Our team at CSIRO’s Astronomy and Space Science division has smashed this record by surveying 83% of the sky in just ten days.</p>
<p>With the <a href="https://research.csiro.au/racs/">RACS survey</a> we produced 903 images, each requiring 15 minutes of exposure time. We then combined these into one map covering the entire area.</p>
<p>The resulting panorama of the radio sky will look surprisingly familiar to anyone who has looked up at the night sky themselves. In our photos, however, nearly all the bright points are entire galaxies, rather than individual stars. </p>
<p>Take our <a href="https://www.atnf.csiro.au/research/RACS/RACStour/index.html">virtual tour</a> below. </p>
<iframe src="https://www.atnf.csiro.au/research/RACS/RACStour/index.html" width="100%" height="500px"></iframe>
<p>Astronomers working on the catalogue have identified about three million galaxies — considerably more than the 260,000 galaxies identified during the Molonglo Sky Survey.</p>
<h2>Why do we need to map the universe?</h2>
<p>We know how important maps are on Earth. They provide crucial navigational assistance and offer information about terrain which is useful for land management.</p>
<p>Similarly, maps of the sky provide astronomers with important context for research and statistical power. They can tell us how certain galaxies behave, such as whether they exist in clusters of companions or drift through space on their own.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/when-you-look-up-how-far-back-in-time-do-you-see-101176">When you look up, how far back in time do you see?</a>
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<p>Being able to conduct an all-sky survey in less than two weeks opens numerous opportunities for research. </p>
<p>For example, little is known about how the radio sky changes over timescales of days to months. We can now regularly revisit each of the three million galaxies identified in the RACS catalogue to track any differences.</p>
<p>Also, some of the largest unanswered questions in astronomy relate to how galaxies became the elliptical, spiral, or irregular shapes we see. A <a href="https://theconversation.com/explainer-a-beginners-guide-to-the-galaxy-49">popular theory</a> suggests large galaxies grow via the merger of many smaller ones. </p>
<p>But the details of this process are elusive and difficult to reconcile with simulations. Understanding the 13 billion or so years of our universe’s cosmic history requires a telescope that can see across vast distances and accurately map everything it finds.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/371886/original/file-20201130-19-9m28tm.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Image of the Centaurus A galaxy." src="https://images.theconversation.com/files/371886/original/file-20201130-19-9m28tm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371886/original/file-20201130-19-9m28tm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371886/original/file-20201130-19-9m28tm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371886/original/file-20201130-19-9m28tm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371886/original/file-20201130-19-9m28tm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371886/original/file-20201130-19-9m28tm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371886/original/file-20201130-19-9m28tm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The giant Centaurus A galaxy was one elliptical galaxy captured in the RACS survey. Although more than ten million light years away, it’s one of the closest radio galaxies to Earth. You can see its ‘intensity’ represented by different colours.</span>
<span class="attribution"><span class="source">CSIRO</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>High technology putting new goals within reach</h2>
<p>The CSIRO’s RACS survey is an amazing advance made possible by huge leaps in space tech. The <a href="https://www.csiro.au/en/Research/Facilities/ATNF/ASKAP">ASKAP radio telescope</a>, which became fully operational in February last year, was designed for speed.</p>
<p>CSIRO’s engineers developed innovative radio receivers called “<a href="https://www.csiro.au/en/Research/Astronomy/ASKAP-and-the-Square-Kilometre-Array/PAFs">phased array feeds</a>” and high-speed digital signal processors specifically for ASKAP. It’s these technologies that provide ASKAP’s wide field of view and rapid surveying capability.</p>
<p>Over the next few years, ASKAP is expected to conduct even more sensitive surveys in different wavelength bands.</p>
<p>In the meantime, the RACS survey catalogue is greatly improving our knowledge of the radio sky. It’ll continue to be a key resource for researchers around the world. </p>
<p>Full resolution images can be downloaded from the <a href="https://data.csiro.au/collections/collection/CIcsiro:46533">ASKAP data archive</a>.</p><img src="https://counter.theconversation.com/content/148442/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aidan Hotan is employed by CSIRO. The ASKAP radio telescope is part of the Australia Telescope National Facility which is managed by CSIRO. Operation of ASKAP is funded by the Australian Government. ASKAP uses the resources of the Pawsey Supercomputing Centre. Establishment of ASKAP, the Murchison Radio-astronomy Observatory and the Pawsey Supercomputing Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund. We acknowledge the Wajarri Yamaji people as the traditional owners of the Observatory site.</span></em></p>Researchers have spotted millions of galaxies in the most detailed radio survey of the southern sky ever conducted. It has smashed previous records for survey speed.Aidan Hotan, ASKAP lead scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1486522020-10-23T10:53:59Z2020-10-23T10:53:59ZA 4G network on the Moon is bad news for radio astronomy<p>As you drive down the road leading to Jodrell Bank Observatory, a sign asks visitors to turn off their mobile phones, stating that the Lovell telescope is so powerful it could detect a phone signal on Mars. </p>
<p>Radio telescopes are designed to be incredibly sensitive. To quote the legendary astronomer <a href="https://www.youtube.com/watch?v=bzS39oghcnY">Carl Sagan</a>, “The total amount of energy from outside the solar system ever received by all the radio telescopes on the planet Earth is less than the energy of a single snowflake striking the ground.” </p>
<p>The total energy now is probably a few snowflakes’ worth, but nevertheless it is still true that astronomical radio signals are typically magnitudes smaller than artificial ones. If Jodrell Bank could pick up interference from a phone signal on Mars, how would it fare with an entire 4G network on the Moon?</p>
<p>That is the issue that is worrying astronomers like me, now that <a href="https://www.nasa.gov/press-release/nasa-announces-partners-to-advance-tipping-point-technologies-for-the-moon-mars">Nokia of America</a> has been awarded US$14.1m (£10.8m) for the development of the first ever cellular network on the Moon. The <a href="https://www.nokia.com/about-us/news/releases/2020/10/19/nokia-selected-by-nasa-to-build-first-ever-cellular-network-on-the-moon/">LTE/4G network</a> will aim to facilitate long term lunar habitability, providing communications for key aspects such as lunar rovers and navigation. </p>
<h2>Network interference</h2>
<p>Radio frequency interference (RFI) is the long-term nemesis of radio astronomers. Jodrell Bank – the earliest radio astronomy observatory in the world still in existence – was created <a href="https://academic.oup.com/astrogeo/article/53/6/6.34/216208">because of RFI</a>. Sir Bernard Lovell, one of the pioneers of radio astronomy, found his work at Manchester hampered by RFI from passing trams in the city, and he persuaded the university’s botany department to let him move to their fields in Cheshire for two weeks (he never left). </p>
<p>Since then, radio telescopes have been built more and more remotely in an attempt to avoid RFI, with the upcoming Square Kilometre Array (SKA) telescope being built across remote areas of South Africa and Australia. This helps to cut out many common sources for RFI, including mobile phones and <a href="https://theconversation.com/how-we-found-the-source-of-the-mystery-signals-at-the-dish-41523">microwave ovens</a>. However, ground-based radio telescopes cannot completely avoid space-based sources of RFI such as satellites – or a future lunar telecommunications network. </p>
<p>RFI can be mitigated at the source with appropriate shielding and precision in the emission of signals. Astronomers are constantly developing strategies to cut RFI from their data. But this increasingly relies on the goodwill of private companies to ensure that at least some radio frequencies are protected for astronomy. </p>
<p>A long-term dream of many radio astronomers would be to have a radio telescope on the far side of the Moon. In addition to being shielded from Earth-based signals, it would also be able to observe at the lowest radio frequencies, which on Earth are particularly affected by a part of the atmosphere called <a href="https://www.aanda.org/articles/aa/abs/2018/07/aa33012-18/aa33012-18.html">the ionosphere</a>. Observing at low radio frequencies can help answer fundamental questions about the universe, such as what it was like in the first few moments after the big bang.</p>
<p>The science case has already been recognised with the <a href="https://www.ru.nl/astrophysics/radboud-radio-lab/projects/netherlands-china-low-frequency-explorer-ncle/">Netherlands-China Low Frequency Explorer</a>, a telescope <a href="https://phys.org/news/2019-11-dutch-chinese-radio-telescope-antennas-unfolded.html">repurposed</a> from the Queqiao relay satellite sent to the Moon in the Chang’e 4 mission . Nasa has also funded a project on the feasibility of turning a <a href="https://www.nasa.gov/directorates/spacetech/niac/2020_Phase_I_Phase_II/lunar_crater_radio_telescope/">lunar crater into a radio telescope</a> with a lining of wire mesh.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/china-lands-on-the-far-side-of-moon-here-is-the-science-behind-the-mission-108566">China lands on the far side of moon – here is the science behind the mission</a>
</strong>
</em>
</p>
<hr>
<h2>It’s not just 4G</h2>
<p>Despite its interest in these radio projects, Nasa also has its eye commercial partnerships. Nokia is just one of 14 American companies Nasa <a href="https://www.nasa.gov/press-release/nasa-announces-partners-to-advance-tipping-point-technologies-for-the-moon-mars">is working with</a> in a new set of partnerships, worth more than US$370m, for the development of its <a href="https://theconversation.com/artemis-accords-why-many-countries-are-refusing-to-sign-moon-exploration-agreement-148134">Artemis programme</a>, which aims to return astronauts to the Moon by 2024. </p>
<p>The involvement of private companies in space technology is not new. And the <a href="https://theconversation.com/if-space-race-is-to-return-we-must-ensure-conflicts-on-earth-do-not-continue-in-space-31803">rights and wrongs</a> have long been debated. Drawing possibly the most attention has been SpaceX’s <a href="https://theconversation.com/lights-in-the-sky-from-elon-musks-new-satellite-network-have-stargazers-worried-117829">Starlink satellites</a>, which caused a stir among astronomers after their first major launch in 2019.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/space-junk-astronomers-worry-as-private-companies-push-ahead-with-satellite-launches-137572">Space junk: Astronomers worry as private companies push ahead with satellite launches</a>
</strong>
</em>
</p>
<hr>
<p>Images quickly began to emerge with trails of Starlink satellites cutting across them – <a href="https://theconversation.com/the-costly-collateral-damage-from-elon-musks-starlink-satellite-fleet-138553">often obscuring</a> or outshining the original astronomical targets.</p>
<figure class="align-center ">
<img alt="A field of next generation radio telescopes." src="https://images.theconversation.com/files/364992/original/file-20201022-18-8tcy94.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/364992/original/file-20201022-18-8tcy94.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/364992/original/file-20201022-18-8tcy94.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/364992/original/file-20201022-18-8tcy94.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/364992/original/file-20201022-18-8tcy94.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/364992/original/file-20201022-18-8tcy94.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/364992/original/file-20201022-18-8tcy94.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">An artist’s impression of the planned SKA-mid dishes in Africa.</span>
<span class="attribution"><a class="source" href="https://www.skatelescope.org/multimedia/image/ska-mid-africa-close-up-artists-impression/">SKA Organisation</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Astronomers have had to deal with satellites for a long time, but Starlink’s numbers and brightness are unprecedented and and their orbits are <a href="https://www.forbes.com/sites/startswithabang/2020/01/30/dangers-to-astronomy-intensify-with-spacexs-latest-starlink-launch/#7974bd886a57">difficult to predict</a>. These concerns apply to anyone doing ground-based astronomy, whether they use an optical or a radio telescope.</p>
<p>A <a href="https://www.skatelescope.org/news/skao-satellite-impact-analysis/">recent analysis</a> of satellite impact on radio astronomy was released by the SKA Organisation, which is developing the next generation of radio telescope technology for the Square Kilometre Array. It calculated that the SKA telescopes would be 70% less sensitive in the radio band that Starlink uses for communications, assuming an eventual number of 6,400 Starlink satellites. </p>
<p>As space becomes more and more commercialised, the sky is filling with an increasing volume of technology. That is why it has never been more important to have regulations protecting astronomy. To help ensure that as we take further steps into space, we’ll still be able to gaze at it from our home on Earth.</p><img src="https://counter.theconversation.com/content/148652/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Alexander 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>Radio telescopes are incredibly sensitive to phone network interference.Emma Alexander, PhD Candidate in Astrophysics, University of ManchesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1382052020-05-12T19:47:10Z2020-05-12T19:47:10ZExperts solve the mystery of a giant X-shaped galaxy, with a monster black hole as its engine<p>A team of US and South African researchers has <a href="https://arxiv.org/abs/2005.02723">published</a> highly detailed images of the largest X-shaped “radio galaxy” ever discovered – PKS 2014-55.</p>
<p>Notably, they’ve helped resolve ongoing confusion about the galaxy’s unusual shape.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/334265/original/file-20200512-175224-f1dbkn.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/334265/original/file-20200512-175224-f1dbkn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/334265/original/file-20200512-175224-f1dbkn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=732&fit=crop&dpr=1 600w, https://images.theconversation.com/files/334265/original/file-20200512-175224-f1dbkn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=732&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/334265/original/file-20200512-175224-f1dbkn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=732&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/334265/original/file-20200512-175224-f1dbkn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=920&fit=crop&dpr=1 754w, https://images.theconversation.com/files/334265/original/file-20200512-175224-f1dbkn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=920&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/334265/original/file-20200512-175224-f1dbkn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=920&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 MeerKAT image of the giant X-shaped radio galaxy PKS 2014-55.</span>
<span class="attribution"><span class="source">Courtesy of SARAO and Bill Cotton et al/Author provided (no reuse)</span></span>
</figcaption>
</figure>
<p>The <a href="https://www.sarao.ac.za/media-releases/south-africas-meerkat-solves-mystery-of-x-galaxies/">spectacular new images</a> were taken using the 64-antenna <a href="https://www.sarao.ac.za/science-engineering/meerkat/about-meerkat/">MeerKAT</a> telescope in South Africa, by an international research team led by Bill Cotton of the US National Radio Astronomy Observatory. </p>
<h2>Zooming in on a cosmic giant</h2>
<p>Our research team also took detailed images of galaxy PKS 2014-55 last year, as part of the <a href="https://en.wikipedia.org/wiki/Evolutionary_Map_of_the_Universe">Evolutionary Map of the Universe project</a> led
by astrophysicist <a href="https://www.atnf.csiro.au/people/Ray.Norris/">Ray Norris</a>. We used CSIRO’s <a href="https://www.csiro.au/en/Research/Astronomy/ASKAP-and-the-Square-Kilometre-Array/SKA">Australian Square Kilometre Array Pathfinder</a> (ASKAP) telescope in Western Australia, which just completed its first set of pilot astronomical surveys. </p>
<p>Thanks to its innovative “radio cameras”, ASKAP can rapidly map very large areas of the sky to catalogue millions of objects emitting radio waves, from nearby supernova remnants to distant galaxies.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/334287/original/file-20200512-175219-s8xxo0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/334287/original/file-20200512-175219-s8xxo0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=782&fit=crop&dpr=1 600w, https://images.theconversation.com/files/334287/original/file-20200512-175219-s8xxo0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=782&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/334287/original/file-20200512-175219-s8xxo0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=782&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/334287/original/file-20200512-175219-s8xxo0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=983&fit=crop&dpr=1 754w, https://images.theconversation.com/files/334287/original/file-20200512-175219-s8xxo0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=983&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/334287/original/file-20200512-175219-s8xxo0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=983&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Our ASKAP image of the giant X-shaped radio galaxy PKS 2014-55.</span>
<span class="attribution"><span class="source">CSIRO and the EMU team/Author provided (no reuse).</span></span>
</figcaption>
</figure>
<p>The prominent X-shape of PKS 2014-55 is made up of two pairs of <a href="https://blog.galaxyzoo.org/2014/02/03/the-curious-lives-of-radio-galaxies-part-one/">giant lobes</a> consisting of hot jets of electrons. These jets spurt outwards from a <a href="https://astronomy.swin.edu.au/cosmos/S/Supermassive+Black+Hole">supermassive black hole</a> at the galaxy’s heart.</p>
<p>The lobes emit electromagnetic radiation in the form of radio waves, which can only be detected by radio telescopes like <a href="https://www.csiro.au/en/Research/Facilities/ATNF/ASKAP">ASKAP</a>. Humans can’t see radio waves. But if we could, from Earth PKS 2014-55 would look about the same size as the Moon.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-the-universe-looks-like-when-viewed-with-radio-eyes-66381">What the universe looks like when viewed with radio eyes</a>
</strong>
</em>
</p>
<hr>
<h2>What makes a radio galaxy?</h2>
<p>Typically, <a href="https://en.wikipedia.org/wiki/Radio_galaxy">radio galaxies</a> have only one pair of lobes. One is a “jet” and the other a “counter-jet”. </p>
<p>These jets expand into the surrounding space at nearly the speed of light. They initially move in a straight line, but twist and bend into many marvellous shapes as they encounter their surroundings. </p>
<p>Centaurus A, seen below, is an example of a giant elliptical galaxy with two prominent radio lobes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/334245/original/file-20200512-66657-3w0228.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/334245/original/file-20200512-66657-3w0228.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/334245/original/file-20200512-66657-3w0228.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/334245/original/file-20200512-66657-3w0228.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/334245/original/file-20200512-66657-3w0228.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/334245/original/file-20200512-66657-3w0228.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/334245/original/file-20200512-66657-3w0228.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/334245/original/file-20200512-66657-3w0228.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This is an artist’s impression of the famous Centaurus A galaxy, which has two prominent radio lobes emerging from its central black hole.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/gsfc/18199018792/in/photolist-tJbJf5-2dNEVuC-29htjhd-EEHmKy-rzqGTD-95Yds7-VWRqoY-9KgqiH-qLsNuo-2hREZpf-2i9UMm7-U7eWMd-2h9dNaZ-2hcZa9a-2gGzwWB-2g2YXPm-26Twqde-2iyBv3a-D2Jexx-2dYDFz5-HbrkoD-2iKYoeb-2ecFGiW-S9bNa5-2hn6G22-2i2DXQD-2icZgrT-2f7Tk25-YW3jMi-dyhNrD-tv7Viw-2ioaJLK-2cPDMFH-2iw39Y4-Nf1txG-wTUY9C-2hmvcEb-25jHWii-2hSYj8B-dxh7au-2iRWf2C-2iw2z2v-YW3DJX-PNyWWK-fue4yp-6JLH7w-2hUxAFv-7Hb1Zt-6Zfmp7-9KgqhX">NASA Goddard Space Flight Center/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Galaxy PKS 2014-55’s <a href="https://blog.galaxyzoo.org/2014/02/04/the-curious-lives-of-radio-galaxies-part-two/">giant X-shape</a>, with two pairs of lobes emerging at very different angles, is highly unusual. </p>
<h2>What makes the lobes?</h2>
<p>To understand why having two pairs of lobes is unusual, we first need to understand what creates the lobes.</p>
<p>Nearly all big galaxies have a supermassive black hole at their centre. </p>
<p>In an active galaxy, powerful jets of charged particles can emerge from the area around the supermassive black hole. Astronomers believe these are emitted from near the poles of the black hole, which is why there are two of them, and they usually point in opposite directions.</p>
<p>When the black hole’s activity stops, the jets stop growing and the material in them flows back towards the centre. Thus, what we see as one lobe of a radio galaxy is made up of both a jet spurting out, and the backflow material.</p>
<h2>A mystery solved</h2>
<p>In the past, there were two major theories for why PKS 2014-55 has two pairs of lobes. </p>
<p>The first suggested there were actually <em>two</em> massive active black holes at the galaxy’s centre, each emitting two <a href="https://blog.galaxyzoo.org/2014/01/22/how-do-black-holes-form-jets/">powerful jets</a>. </p>
<p>The second theory suggested the supermassive black hole had undergone a <a href="https://en.wikipedia.org/wiki/Spin-flip">spin flip</a>. This is when a rotating black hole’s spin axis has a sudden change in orientation, resulting in a second pair of jets at a different angle from the first pair.</p>
<p>But the recent observations from the South African MeerKAT telescope strongly suggest a third possibility: that the two larger lobes are the fast-moving particles zooming out from the black hole, while the two smaller lobes are the backflow looping around to fall back in.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/334263/original/file-20200512-175262-bogw1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/334263/original/file-20200512-175262-bogw1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/334263/original/file-20200512-175262-bogw1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=335&fit=crop&dpr=1 600w, https://images.theconversation.com/files/334263/original/file-20200512-175262-bogw1y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=335&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/334263/original/file-20200512-175262-bogw1y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=335&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/334263/original/file-20200512-175262-bogw1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=420&fit=crop&dpr=1 754w, https://images.theconversation.com/files/334263/original/file-20200512-175262-bogw1y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=420&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/334263/original/file-20200512-175262-bogw1y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=420&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The South African Radio Astronomy Observatory’s MeerKAT telescope array consists of 64 radio dishes (pictured). Computers combine signals from these antennas to synthesise a telescope eight kilometres in diameter.</span>
<span class="attribution"><span class="source">SARAO/Author provided (no reuse)</span></span>
</figcaption>
</figure>
<p>The MeerKAT team achieved high-resolution images ten times more sensitive than our ASKAP pilot observations conducted here in Australia last year. </p>
<h2>A cosmic wonder</h2>
<p>Using <a href="https://www.csiro.au/en/Research/Facilities/ATNF/ASKAP">CSIRO’s ASKAP</a> telescope, our team observed the “purple butterfly” of PKS 2014-55 to be an enormous cosmic structure. It spans at least five million light years – about 20 times the size of our own Milky Way galaxy. </p>
<p>PKS 2014-55 is located on the outskirts of a massive cluster of galaxies known as Abell 3667. It was discovered more than 60 years ago using the <a href="https://www.atnf.csiro.au/news/newsletter/jun02/Flowering_of_Fleurs.htm">Mills Cross Telescope</a> at CSIRO’s old <a href="https://www.environment.nsw.gov.au/heritageapp/ViewHeritageItemDetails.aspx?id=2260832">Fleurs field station</a> in New South Wales. </p>
<p>The galaxy was first seen by <a href="https://www.atnf.csiro.au/people/rekers/">Ron Ekers</a> using the <a href="https://www.cambridge.org/core/journals/publications-of-the-astronomical-society-of-australia/article/parkes-interferometer/9EB4F096050C7F3A8020E3770444C1E7">Parkes Interferometer</a> in 1969.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-brain-transplant-for-one-of-australias-top-telescopes-129138">A brain transplant for one of Australia's top telescopes</a>
</strong>
</em>
</p>
<hr>
<h2>ASKAP</h2>
<p>The ASKAP telescope we used to capture PKS 2014-55 is an array of 36 radio dishes laid out in a pattern six kilometres in diameter. Together, the dishes make up a large radio telescope that uses Earth’s rotation to produce sharp images of astronomical sources near and far. </p>
<p>Each dish is 12m wide and <a href="https://www.csiro.au/en/Research/Astronomy/ASKAP-and-the-Square-Kilometre-Array/PAFs">equipped</a> with new technologies developed by CSIRO and industry partners. ASKAP is a fast survey machine, taking radio images over very wide areas of the sky. Several surveys of the entire sky are expected to start next year.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/333671/original/file-20200508-49546-110hle4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/333671/original/file-20200508-49546-110hle4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=298&fit=crop&dpr=1 600w, https://images.theconversation.com/files/333671/original/file-20200508-49546-110hle4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=298&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/333671/original/file-20200508-49546-110hle4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=298&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/333671/original/file-20200508-49546-110hle4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=375&fit=crop&dpr=1 754w, https://images.theconversation.com/files/333671/original/file-20200508-49546-110hle4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=375&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/333671/original/file-20200508-49546-110hle4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=375&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Australian Square Kilometre Array (ASKAP) radio telescope, located in the Murchison Shire in Western Australia.</span>
</figcaption>
</figure>
<hr>
<p><em>We acknowledge the Wajarri Yamatji as the traditional owners of the Murchison Radio-astronomy Observatory site.</em></p><img src="https://counter.theconversation.com/content/138205/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Baerbel Koribalski 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>Like a cosmic butterfly in the sky, radio galaxy PKS 2014-55 was observed by CSIRO researchers with the Australian SKA Pathfinder telescope.Baerbel Koribalski, Senior research scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1302132020-01-26T09:18:52Z2020-01-26T09:18:52ZIn a rare sighting, astronomers observe burst of activity as a massive star forms<figure><img src="https://images.theconversation.com/files/310940/original/file-20200120-69535-11mh6cx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This artist's impression shows the blast from a heatwave detected in a massive, forming star.
</span> <span class="attribution"><span class="source">Katharina Immer/JIVE</span></span></figcaption></figure><p>Here on Earth, we pay quite a lot of attention to the sun. It’s visible to us, after all, and central to our lives. But it is only one of the billions of stars in our galaxy, the Milky Way. It’s also quite small compared to other stars – many are at least eight times more <a href="https://academic.oup.com/astrogeo/article/53/4/4.30/225742">massive</a>. </p>
<p>These massive stars influence the structure, shape and chemical content of a galaxy. And when they have exhausted their hydrogen gas fuel and die, they do so in an explosive event called <a href="https://spaceplace.nasa.gov/supernova/en/">a supernova</a>. This explosion is sometimes so strong that it triggers the formation of new stars out of materials in the dead star’s surroundings. </p>
<p>But there’s an important gap in our knowledge: astronomers don’t yet fully understand how those original massive stars themselves are initially formed. So far, observations have only yielded some pieces of the puzzle. This is because nearly all the known massive stars in our galaxy are located very far away from our solar system. They also form in close proximity to other massive stars, making it difficult to study the environment where they take shape. </p>
<p>One theory, though, is that a rotating disc of gas and dust funnels materials into the growing star. </p>
<p>Astronomers have <a href="https://www.nature.com/articles/nphys3942">recently found</a> that the funnelling of matter into a forming star happens at different rates over time. Sometimes the forming star swallows up a huge amount of matter, resulting in a burst of activities in the massive star. This is called an accretion burst event. It is incredibly rare: only three such events have been observed, out of all the billions of massive stars in the Milky Way.</p>
<p>This is why astronomers are so excited about <a href="https://www.nature.com/articles/s41550-019-0989-3">a recent observation</a> of the phenomenon. I was part of the team that recorded this observation. Now, our team and other astronomers will be able to develop and test theories to explain how high-mass stars gain their mass.</p>
<h2>A global collaboration</h2>
<p>After the <a href="https://www.nature.com/articles/nphys3942?proof=trueIn%EF%BB%BF">first detection of an accretion burst</a>, in 2016, astronomers from around the world <a href="http://iaus336.oa-cagliari.inaf.it">agreed</a> in 2017 to coordinate their efforts to observe more. Reported bursts have to be validated and followed up with more observations, and this takes a joint, global effort – which led to the formation of the <a href="https://www.masermonitoring.com">Maser Monitoring Organisation</a> (M2O). </p>
<p>A <a href="https://www.britannica.com/technology/maser">maser</a> is the microwave (radio frequency) equivalent of laser. The word stands for “microwave amplification by stimulated emission of radiation”. Masers are observed using radio telescopes and most of them are observed at centimetre wavelength: they are very compact.</p>
<p>A maser flare can be a sign of an extraordinary event such as the formation of a star. Since 2017 radio telescopes in Japan, Poland, Italy, China, Russia, Australia, New Zealand and South Africa (<a href="http://www.hartrao.ac.za">HartRAO</a>, in the country’s Gauteng province) have been working together to detect a flare stimulated by a burst in the funnelling of materials into a massive star. </p>
<p>In January 2019, astronomers at Ibaraki University in Japan noticed that one such massive protostar, G358-MM1, showed signs of new activity. The masers associated with the object brightened significantly over a short period of time. The theory is that masers brighten when excited by an accretion burst.</p>
<p>Follow-up observations with the Australian Long Baseline Array revealed something astronomers are <a href="https://www.nature.com/articles/s41550-019-0989-3">witnessing for the first time</a> – a blast of heat-wave coming from the source and travelling through the surroundings of the forming big star. Blasts can last for about two weeks to a few months. </p>
<h2>Burst of energy</h2>
<p>Blasts like this were not observed in the previous two accretion bursts in massive stars. This may imply that it’s a different kind of accretion burst. There may even be a “zoo” of accretion burst types – a whole range of different types which act in different ways that may depend on the mass and evolutionary stage of the young star.</p>
<p>Although the burst activity has died down, the masers are still a lot brighter than they were before the burst. Astronomers are watching with interest to see whether a similar burst will occur again, and at what scale. </p>
<p>This experience shows how valuable it is to have lots of eyes on the sky, from different corners of the globe. Collaboration is astronomy is crucial for new, important discoveries.</p><img src="https://counter.theconversation.com/content/130213/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Okwe Chibueze works for North-West University. He receives funding from National Research Foundation. </span></em></p>This observation means astronomers can now develop and test theories that explain how high-mass stars gain their mass.James Okwe Chibueze, Associate Professor, North-West UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1299192020-01-15T23:23:37Z2020-01-15T23:23:37ZThe Dish in Parkes is scanning the southern Milky Way, searching for alien signals<figure><img src="https://images.theconversation.com/files/309915/original/file-20200114-151853-19x0fb7.jpg?ixlib=rb-1.1.0&rect=0%2C13%2C3008%2C1981&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Parkes radio telescope can detect extremely weak signals coming from the most distant parts of the Universe.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>For John Sarkissian, operations scientist at the CSIRO Parkes radio telescope, astronomy has been his life’s passion – starting from the age of six. </p>
<p>“When I was six years old, I watched Neil Armstrong and Buzz Aldrin walk on the Moon,” he says of the radio telescope made famous in the film The Dish.</p>
<p>“In fact, on the cover of my year nine mathematics textbook was a painting of the Parkes radio telescope. I remember sitting in the class staring at the painting and daydreaming working there one day. And so here I am now, 40 some years later.”</p>
<p>Today, on Trust Me I’m An Expert, editorial intern Antonio Tarquinio speaks to Sarkissian about the research underway at one of Australia’s most famous astronomical research facilities including:</p>
<ul>
<li><p>the role Parkes is playing right now in the search for extra-terrestrial intelligence</p></li>
<li><p>how the telescope detects extremely weak signals coming from the most distant parts of the Universe</p></li>
<li><p>why even a light breeze can imperil the dish unless it’s in the right position</p></li>
<li><p>how the explosion of phones, wi-fi and radio frequency interference is affecting research in the once-deserted Parkes location.</p></li>
</ul>
<p>And Sarkissian’s own take on whether Parkes will help find alien life?</p>
<p>“Well, as of today, the only place we know of the entire Universe that there is definitely life is right here on Earth,” he says. </p>
<p>“And what does that say? It says that we should appreciate our place in the Universe a little more.”</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-size-the-grandeur-the-peacefulness-of-being-in-the-dark-what-its-like-to-study-space-at-siding-spring-observatory-128998">'The size, the grandeur, the peacefulness of being in the dark': what it's like to study space at Siding Spring Observatory</a>
</strong>
</em>
</p>
<hr>
<h2>New to podcasts?</h2>
<p>Podcasts are often best enjoyed using a podcast app. All iPhones come with the Apple Podcasts app already installed, or you may want to listen and subscribe on another app such as Pocket Casts (click <a href="https://pca.st/VTv7">here</a> to listen to Trust Me, I’m An Expert on Pocket Casts).</p>
<p>You can also hear us on Stitcher, Spotify or any of the apps below. Just pick a service from one of those listed below and click on the icon to find Trust Me, I’m An Expert.</p>
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<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/trust-me-im-an-expert-what-science-says-about-how-to-lose-weight-and-whether-you-really-need-to-122635">Trust Me, I'm An Expert: what science says about how to lose weight and whether you really need to</a>
</strong>
</em>
</p>
<hr>
<p><strong>Additional audio</strong></p>
<p><em>Kindergarten by Unkle Ho, from <a href="https://www.elefanttraks.com/">Elefant Traks.</a></em></p>
<p><em>Extra Dimension by Kri Tik, from <a href="https://freemusicarchive.org/music/Kri_Tik">Free Music Archive</a></em></p>
<h2>Images</h2>
<p><em>Shutterstock</em></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/darkness-is-disappearing-and-thats-bad-news-for-astronomy-51989">Darkness is disappearing and that's bad news for astronomy</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/129919/count.gif" alt="The Conversation" width="1" height="1" />
Today we hear about the Parkes radio telescope's role in the search for alien life. Our guide is the irrepressible John Sarkissian, the scientist who's had his eye on The Dish since childhood.Sunanda Creagh, Senior EditorAntonio Tarquinio, Editorial InternLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1289982019-12-18T18:58:08Z2019-12-18T18:58:08Z‘The size, the grandeur, the peacefulness of being in the dark’: what it’s like to study space at Siding Spring Observatory<figure><img src="https://images.theconversation.com/files/307307/original/file-20191217-123992-12tnqvo.jpg?ixlib=rb-1.1.0&rect=8%2C17%2C5739%2C3025&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Today we hear about some of the fascinating space research underway at Siding Spring Observatory – and how, despite gruelling hours and endless paperwork, astronomers retain their sense of wonder for the night sky.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>How did our galaxy form? How do galaxies evolve over time? Where did the Sun’s lost siblings end up?</p>
<p>Three hours north-east of Parkes lies a remote astronomical research facility, unpolluted by city lights, where researchers are collecting vast amounts of data in an effort to unlock some of the biggest questions about our Universe. </p>
<p>Siding Spring Observatory, or SSO, is one of Australia’s top sites for astronomical research. You’ve probably heard of the Parkes telescope, made famous by the movie The Dish, but SSO is also a key character in Australia’s space research story.</p>
<p>In this episode, astrophysics student and Conversation intern Cameron Furlong goes to SSO to check out the huge Anglo Australian Telescope (AAT), the largest optical telescope in Australia.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307308/original/file-20191217-124022-j2z8ws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307308/original/file-20191217-124022-j2z8ws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307308/original/file-20191217-124022-j2z8ws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307308/original/file-20191217-124022-j2z8ws.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307308/original/file-20191217-124022-j2z8ws.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307308/original/file-20191217-124022-j2z8ws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307308/original/file-20191217-124022-j2z8ws.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307308/original/file-20191217-124022-j2z8ws.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"></a>
<figcaption>
<span class="caption">Siding Spring Observatory, north east of Parkes.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/darkness-is-disappearing-and-thats-bad-news-for-astronomy-51989">Darkness is disappearing and that's bad news for astronomy</a>
</strong>
</em>
</p>
<hr>
<p>And we hear about Huntsman, a new specialised telescope that uses off-the-shelf Canon camera lenses – a bit like those you see sports photographers using at the cricket or the footy – to study very faint regions of space around other galaxies.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/307298/original/file-20191216-124016-b2k0ag.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307298/original/file-20191216-124016-b2k0ag.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/307298/original/file-20191216-124016-b2k0ag.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307298/original/file-20191216-124016-b2k0ag.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307298/original/file-20191216-124016-b2k0ag.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307298/original/file-20191216-124016-b2k0ag.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307298/original/file-20191216-124016-b2k0ag.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307298/original/file-20191216-124016-b2k0ag.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Students use telescopes to observe the night sky near Coonabarabran, not far from SSO.</span>
<span class="attribution"><span class="source">Cameron Furlong</span></span>
</figcaption>
</figure>
<p>Listen in to hear more about some of the most fascinating space research underway in Australia – and how, despite gruelling hours and endless paperwork, astronomers retain their sense of wonder for the night sky. </p>
<p>“For me, it means remembering how small I am in this enormous Universe. I think it’s very easy to forget, when you go about your daily life,” said Richard McDermid, an ARC Future Fellow and astronomer at Macquarie University.</p>
<p>“It’s nice to get back into it to a dark place and having a clear sky. And then you get to remember all the interesting and fascinating things, the size, the grandeur and the peacefulness of being in the dark.”</p>
<h2>New to podcasts?</h2>
<p>Podcasts are often best enjoyed using a podcast app. All iPhones come with the Apple Podcasts app already installed, or you may want to listen and subscribe on another app such as Pocket Casts (click <a href="https://pca.st/VTv7">here</a> to listen to Trust Me, I’m An Expert on Pocket Casts).</p>
<p>You can also hear us on Stitcher, Spotify or any of the apps below. Just pick a service from one of those listed below and click on the icon to find Trust Me, I’m An Expert.</p>
<p><a href="https://itunes.apple.com/au/podcast/trust-me-im-an-expert/id1290047736?mt=2&ign-mpt=uo%3D8"><img src="https://images.theconversation.com/files/233721/original/file-20180827-75984-1gfuvlr.png" alt="Listen on Apple Podcasts" width="268" height="68"></a> <a href="https://www.google.com/podcasts?feed=aHR0cHM6Ly90aGVjb252ZXJzYXRpb24uY29tL2F1L3BvZGNhc3RzL3RydXN0LW1lLXBvZGNhc3QucnNz"><img src="https://images.theconversation.com/files/233720/original/file-20180827-75978-3mdxcf.png" alt="" width="268" height="68"></a></p>
<p><a href="https://www.stitcher.com/podcast/the-conversation/trust-me-im-an-expert"><img src="https://images.theconversation.com/files/233716/original/file-20180827-75981-pdp50i.png" alt="Stitcher" width="300" height="88"></a> <a href="https://tunein.com/podcasts/News--Politics-Podcasts/Trust-Me-Im-An-Expert-p1035757/"><img src="https://images.theconversation.com/files/233723/original/file-20180827-75984-f0y2gb.png" alt="Listen on TuneIn" width="318" height="125"></a></p>
<p><a href="https://radiopublic.com/trust-me-im-an-expert-Wa3E5A"><img class="alignnone size-medium wp-image-152" src="https://images.theconversation.com/files/233717/original/file-20180827-75990-86y5tg.png?ixlib=rb-1.1.0&q=45&auto=format&w=268&fit=clip" alt="Listen on RadioPublic" width="268" height="87"></a> <a href="https://open.spotify.com/show/7myc7drbLJVaRitAMXLB7V"><img src="https://images.theconversation.com/files/237984/original/file-20180925-149976-1ks72uy.png?ixlib=rb-1.1.0&q=45&auto=format&w=268&fit=clip" width="268" height="82"></a> </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/trust-me-im-an-expert-what-science-says-about-how-to-lose-weight-and-whether-you-really-need-to-122635">Trust Me, I'm An Expert: what science says about how to lose weight and whether you really need to</a>
</strong>
</em>
</p>
<hr>
<p><strong>Additional audio</strong></p>
<p><em>Kindergarten by Unkle Ho, from <a href="https://www.elefanttraks.com/">Elefant Traks.</a></em></p>
<p><em><a href="https://freemusicarchive.org/music/Podington_Bear/Textural/Lucky_Stars_1189">Lucky Stars</a> by Podington Bear from Free Music Archive.</em></p>
<p><em><a href="https://freemusicarchive.org/music/Blue_Dot_Sessions/20190309173200900/Slimheart">Slimheart by Blue Dot Sessions</a> from Free Music Archive.</em></p>
<p><em><a href="https://freemusicarchive.org/music/Kai_Engel">Illumination</a> by Kai Engel from Free Music Archive.</em></p>
<p><em><a href="https://freemusicarchive.org/music/Xylo-Ziko/Phase_2">Phase 2 by Xylo-Ziko</a> from Free Music Archive.</em></p>
<p><em><a href="https://freemusicarchive.org/music/Kri_Tik">Extra Dimensions by Kri Tik</a> from Free Music Archive.</em></p>
<p><em><a href="https://freemusicarchive.org/music/Meydan">Pure Water by Meydän</a>, from Free Music Archive.</em></p>
<h2>Images</h2>
<p><em>Shutterstock</em></p>
<p><em>Cameron Furlong</em></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/antibiotic-resistant-superbugs-kill-32-plane-loads-of-people-a-week-we-can-all-help-fight-back-125813">Antibiotic resistant superbugs kill 32 plane-loads of people a week. We can all help fight back</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/128998/count.gif" alt="The Conversation" width="1" height="1" />
Three hours north-east of Parkes lies a remote astronomical research facility, unpolluted by city lights, where researchers are trying to unlock some of the biggest questions about our Universe.Sunanda Creagh, Senior EditorCameron Furlong, Editorial InternLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1150642019-04-10T23:46:45Z2019-04-10T23:46:45ZObserving the invisible: the long journey to the first image of a black hole<figure><img src="https://images.theconversation.com/files/268696/original/file-20190410-2921-19jg4e0.jpg?ixlib=rb-1.1.0&rect=863%2C436%2C1670%2C1063&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The first direct visual evidence of the supermassive black hole in the centre of galaxy Messier 87 and its shadow.</span> <span class="attribution"><a class="source" href="https://www.eso.org/public/images/eso1907a/">EHT Collaboration</a></span></figcaption></figure><p>The first picture of a supermassive black hole at the centre of a galaxy shows how we have, in a sense, observed the invisible.</p>
<p>The <a href="https://www.eso.org/public/images/eso1907a/">ghostly image</a> is a radio intensity map of the glowing plasma behind, and therefore silhouetting, the black hole’s “<a href="http://astronomy.swin.edu.au/cosmos/E/Event+Horizon">event horizon</a>” — the spherical cloak of invisibility around a black hole from which not even light can escape.</p>
<p>The radio “photograph” was obtained by an international collaboration involving more than 200 scientists and engineers who linked some of the world’s most capable radio telescopes to effectively see the supermassive black hole in the galaxy known as M87.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sizes-matters-for-black-hole-formation-but-theres-something-missing-in-the-middle-ground-79576">Sizes matters for black hole formation, but there's something missing in the middle ground</a>
</strong>
</em>
</p>
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<p>So how on Earth did we get to this point?</p>
<h2>From ‘dark stars’</h2>
<p>It was the English astronomer <a href="https://www.britannica.com/biography/John-Michell">John Michell</a> who in 1783 first formulated the idea of “dark stars” so incredibly dense that their gravity would be impossible to run from — even if you happened to be a photon able to move at the speed of light. </p>
<p>Things have come a long way since that pioneering insight.</p>
<p>In January this year, astronomers <a href="http://adsabs.harvard.edu/abs/2019ApJ...871...30I" title="The Size, Shape, and Scattering of Sagittarius A* at 86 GHz: First VLBI with ALMA">published an image</a> of the emission coming from the radio source known as Sagittarius A*, the region immediately surrounding the <a href="http://astronomy.swin.edu.au/cosmos/S/Supermassive+Black+Hole">supermassive black hole</a> at the centre of our galaxy.</p>
<p>Impressively, that image had detail on scales down to just nine times the size of the black hole’s event horizon.</p>
<p>Now, the Event Horizon Telescope (<a href="https://eventhorizontelescope.org/">EHT</a>) has succeeded in resolving the event horizon around the supermassive black hole in M87, a relatively nearby galaxy from which light takes 55 million light years to reach us, due to its distance.</p>
<h2>Astronomical figures</h2>
<p>Astronomical objects come with astronomical figures, and this target is no exception. </p>
<p>M87’s black hole has a mass that is 6.5 billion times that of our Sun, which itself is one-third of a million times the mass of the Earth. Its event horizon has a radius of roughly 20 billion kilometres, more than three times the distance Pluto is from our Sun. </p>
<p>It is, however, far away, and the incredible engineering feat required to see such a target is akin to trying to observe an object 1mm in size from a distance of 13,000km.</p>
<p>This Nobel Prize-worthy result is, of course, no accidental discovery, but a measurement built on generations of insight and breakthrough. </p>
<h2>Predictions without observation</h2>
<p>In the early 1900s, considerable progress occurred after Albert Einstein developed his theories of relativity. These enduring equations link space and time, and dictate the motion of matter which in turn dictates the gravitational fields and waves within spacetime.</p>
<p>Soon after, in 1916, astronomers Karl Schwarzschild and Johannes Droste independently realised that Einstein’s equations gave rise to solutions containing a “mathematical singularity”, an indivisible point of zero volume and infinite mass. </p>
<p>Studying the evolution of stars in the 1920s and 1930s, nuclear physicists reached the seemingly unavoidable conclusion that if massive enough, certain stars would end their lives in a catastrophic gravitational collapse resulting in a singularity and the creation of a “frozen star”.</p>
<p>This term reflected the bizarre relative nature of time in Einstein’s theory. At the event horizon, the infamous boundary of no return surrounding such a collapsed star, time will appear to freeze for an external observer. </p>
<p>While advances in the field of quantum mechanics replaced the notion of a singularity with an equally bewildering but finite quantum dot, the actual surface, and interior, of black holes remains an active area of research today.<br>
While our galaxy may contain millions of John Michell’s stellar-mass black holes — of which we know the whereabouts of a dozen or so — their event horizons are too small to observe. </p>
<p>For example, if our Sun were to collapse down to a black hole, the radius of its event horizon would be just 3km. But the collision of stellar-mass black holes in other galaxies was <a href="http://adsabs.harvard.edu/abs/2016PhRvL.116f1102A" title="Observation of Gravitational Waves from a Binary Black Hole Merger">famously detected</a> using gravitational waves. </p>
<h2>Looking for something supermassive</h2>
<p>The EHT’s targets are therefore related to the supermassive black holes located at the centres of galaxies. The term black hole actually only came into use in the mid- to late 1960s when astronomers began to suspect that truly massive “dark stars” powered the highly active nuclei of certain galaxies. </p>
<p>Numerous theories abound for the formation of these particularly massive black holes. Despite the name, black holes are objects, rather than holes in the fabric of spacetime. </p>
<p>In 1972, <a href="http://adsabs.harvard.edu/full/1972AJ.....77..292S" title="The Distribution of Mass in the Galactic Nucleus">Robert Sanders and Thomas Lowinger</a> calculated that a dense mass equal to about one million solar masses resides at the centre of our galaxy. </p>
<p>By 1978, <a href="http://adsabs.harvard.edu/doi/10.1086/156077" title="Dynamical evidence for a central mass concentration in the galaxy M87">Wallace Sargent and colleagues had determined</a> that a dense mass five billion times the mass of our Sun lies at the centre of the nearby galaxy M87. </p>
<p>But these masses, slightly revised since then, might have simply been a dense swarm of planets and dead stars. </p>
<p>In 1995, the existence of black holes was confirmed observationally by <a href="http://adsabs.harvard.edu/abs/1995Natur.373..127M" title="Evidence for a black hole from high rotation velocities in a sub-parsec region of NGC4258">Makoto Miyoshi and colleagues</a>. Using radio interferometry, they detected a mass at the centre of the galaxy M106, within a volume so small that it could only be, or soon would become, a black hole.</p>
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<a href="https://theconversation.com/first-black-hole-photo-confirms-einsteins-theory-of-relativity-115167">First black hole photo confirms Einstein's theory of relativity</a>
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<p>Today, around 130 such supermassive black holes at the centres of nearby galaxies have had their masses directly measured from the orbital velocities and distances of stars and gas circling the black holes, but not yet on a death spiral into the central gravitational compactor.</p>
<p>Despite the increased sample, our Milky Way and M87 still have the largest event horizons as seen from Earth, which is why the international team pursued these two targets.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1115964692802019328"}"></div></p>
<p>The shadowy silhouette of the black hole in M87 is indeed an astonishing scientific image. While black holes can apparently stop time, it should be acknowledged that the predictive power of science, when coupled with human imagination, ingenuity, and determination, is also a remarkable force of nature.</p><img src="https://counter.theconversation.com/content/115064/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Professor Alister Graham is an Associate Investigator at the Australian Research Council’s Centre of Excellence for Gravitational Wave Discovery, known as OzGrav, headquartered at Swinburne University of Technology in Melbourne. </span></em></p>Astronomers say they have “seen what we thought was unseeable” in releasing the first image of a supermassive black hole. So how did we get to this historic observation?Alister Graham, Professor of Astronomy, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1065562018-11-27T13:17:44Z2018-11-27T13:17:44ZHow scientists are working together to solve one of the universe’s mysteries<figure><img src="https://images.theconversation.com/files/246628/original/file-20181121-161641-1rc00vw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An artist’s impression of fast radio bursts in the sky above the Australian SKA precursor, ASKAP.</span> <span class="attribution"><span class="source">OzGrav, Swinburne University of Technology</span></span></figcaption></figure><p>One of the most baffling puzzles of modern astrophysics is the nature of Fast Radio Bursts, which were <a href="https://arxiv.org/pdf/0709.4301.pdf">discovered in 2007</a>. These are seemingly <a href="http://frbcat.org">rare</a>, extremely bright flashes of light with radio wavelengths. They last <a href="https://arxiv.org/pdf/0709.4301.pdf">only milliseconds</a>; <a href="https://arxiv.org/pdf/1504.00200.pdf">originate outside</a> our galaxy, the Milky Way; come from regions with <a href="https://arxiv.org/pdf/1801.03965.pdf">enormously strong magnetic fields</a>; and <a href="https://arxiv.org/pdf/1505.06220.pdf">pass through a significant amount of gas or dust</a> before reaching Earth. </p>
<p>All of these facts may make it sound as though scientists know a lot about Fast Radio Bursts. In reality, we don’t. For instance, though we know they’re not from our galaxy, we don’t know where exactly they come from. We don’t know what causes them. And we’re not sure whether they might be useful as <a href="https://arxiv.org/abs/1711.11277">cosmological</a> standards to measure the large scale properties of our universe.</p>
<p>Dozens of theories about Fast Radio Bursts have been proposed. Some conform to standard physics. Others are more exotic, including <a href="https://arxiv.org/abs/1807.01976">cosmic strings</a> – hypothetical, one-dimensional structures formed in the early universe – or even rather bizarre: one theory <a href="https://www.newscientist.com/article/2124209-could-fast-radio-bursts-really-be-powering-alien-space-ships">suggests</a> that aliens are responsible.</p>
<p>Now, in an attempt to discover the truth about Fast Radio Bursts, we have created <a href="https://frbtheorycat.org/index.php/Main_Page">a catalogue</a> that lists <a href="https://arxiv.org/abs/1810.05836">each theory</a>, along with its pros and cons. Scientists from around the world can weigh in, and new data and discoveries will be added throughout the process.</p>
<p>Some of this data will come from projects on the African continent, like the <a href="https://theconversation.com/new-telescope-chases-the-mysteries-of-radio-flashes-and-dark-energy-101607">Hydrogen Intensity and Real-time Analysis eXperient</a> (HIRAX), MeerKAT, and the Square Kilometre Array (SKA), which are expected to discover and localise thousands of Fast Radio Bursts.</p>
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Read more:
<a href="https://theconversation.com/africas-meerkat-first-light-images-have-blown-all-expectations-65246">Africa's MeerKAT 'first light' images have blown all expectations</a>
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<p>This platform will produce a great deal of knowledge. It will also provide valuable insight into scientific sociology as international researchers work together and ultimately, we hope, identify the most acceptable model. </p>
<h2>A range of theories</h2>
<p>Perhaps precisely because they are so elusive, Fast Radio Bursts have received a lot of attention from astronomers, astrophysicists, cosmologists, and physicists in the years since their discovery.</p>
<p>These are the main theories that have emerged so far. </p>
<ul>
<li><p>Fast Radio Bursts involve types of neutron stars, such as pulsars (which rotate rapidly) or magnetars (which are highly magnetised). These are probably the most plausible theories, since neutron stars’ intrinsic and extremely large magnetic fields can naturally fulfil the energy requirements for Fast Radio Bursts.</p></li>
<li><p>The merging of astronomical bodies (such as black holes, neutron stars and white dwarfs), and their collapse, has been proposed as a possible origin for Fast Radio Bursts.</p></li>
</ul>
<p>In such processes, enormous amounts of energy are released over short timescales. This could possibly create radiation akin to Fast Radio Bursts.</p>
<ul>
<li><p>some of the more exotic models have a more theoretical basis. They involve hypothetical objects such as quark stars (quarks are the subatomic particles that constitute neutrons and protons), axion stars (axions are extremely light, hypothetical subatomic particles), and <a href="https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy">dark matter</a>: the hypothetical, unobserved matter that is believed to account for 27% of the total matter content of the universe. </p></li>
<li><p>Another fairly improbable theory is that Fast Radio Bursts are lightning striking on pulsars.</p></li>
</ul>
<p>And then there’s the suggestion that Fast Radio Bursts are evidence of aliens. It’s certainly the most unusual of the proposed theories, but it cannot be ruled out as a possibility yet.</p>
<p>Although it’s unlikely, Fast Radio Bursts may be signals from a beacon set up by an extraterrestrial civilisation, or perhaps from light sails that harness photons to travel across the galaxy. </p>
<p>There’s a remarkable variation in these models, and it’s hard work to narrow down the options and reach consensus. Of the 50 theories or models proposed to date, only three have been eliminated. This is what prompted us to set up the catalogue and to invite engagement from the broader scientific community.</p>
<h2>Platform for debate</h2>
<p>It’s no easy task to get scientists talking to each other about Fast Radio Bursts. That’s because the scientists in question have different specialisations and are from all over the world. </p>
<p>The online catalogue provides a suitable and accessible platform for discussion, debate, and the sharing of knowledge. There is also a traceable history, which creates an opportunity for us to study how as humans we work together to solve scientific problems – and perhaps how this process can be optimised in the future. </p>
<p>Part of our motivation, as theoretical physicists, was to develop this engagement and to dive in ourselves. The problems are rich and the waters are deep. </p>
<p>Data about Fast Radio Bursts is starting to pour in now, thanks to such game-changers as MeerKAT and HIRAX. As it arrives, is examined and papers are published, we’ll be able to start ruling out theories and digging deeper into viable theories. Within five years, this mystery could be solved.</p><img src="https://counter.theconversation.com/content/106556/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Platts is supported by a PhD fellowship from the South African National Institute for Theoretical Physics (NITheP).</span></em></p><p class="fine-print"><em><span>Amanda Weltman receives funding from The Department of Science and Technology and the National Research Foundation of South Africa. She is a member of the Global Young Academy and a Next Einstein Forum Laureate. </span></em></p>Perhaps precisely because they are so elusive, Fast Radio Bursts have received a lot of attention in the years since their discovery.Emma Platts, PhD Student, University of Cape TownAmanda Weltman, South African Research Chair in Physical Cosmology, Department of Mathematics and Applied Mathematics, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1044882018-10-10T18:38:07Z2018-10-10T18:38:07ZMore ‘bright’ fast radio bursts revealed, but where do they all come from?<figure><img src="https://images.theconversation.com/files/239726/original/file-20181008-72103-uxpt3w.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Central antennas of the Australia Square Kilometre Array Pathfinder.</span> <span class="attribution"><span class="source">Alex Cherney/CSIRO</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Fast radio bursts (<a href="https://theconversation.com/au/topics/fast-radio-bursts-6352">FRBs</a>) are one of the great astrophysical mysteries. They are brief, bright flashes of radio waves that last a few milliseconds. Despite happening frequently – thousands occur over the entire sky every day – only a couple dozen have ever been seen.</p>
<p>But we’ve found 20 more bursts, averaging one for every 14 days of observing, with the results <a href="http://dx.doi.org/10.1038/s41586-018-0588-y">published in Nature today</a>.</p>
<p>There are two main reasons why astronomers like me are really excited by FRBs. </p>
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Read more:
<a href="https://theconversation.com/askap-telescope-speeds-up-the-hunt-for-new-fast-radio-bursts-77481">ASKAP telescope speeds up the hunt for new Fast Radio Bursts</a>
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<p>First, they represent a new, very unusual, unexpected phenomenon. The bursts come from other galaxies, meaning incredible amounts of energy are required to produce them – some bursts contain more energy than our Sun produces in decades. </p>
<p>Second, FRBs have the potential to be a new tool that we can use to understand the structure of matter in the universe.</p>
<p>The key property of the bursts that could turn them into a valuable tool is their dispersion: shorter (bluer) wavelength radio waves arrive at the telescope before the longer (redder) ones. </p>
<p>This dispersion is the result the radio waves passing through hot gas (plasma), which slows down the radio waves by an amount that depends on the wavelength. The amount of dispersion tells us how much matter the bursts have travelled through, and until now it has been unclear where that matter is. </p>
<figure>
<iframe src="https://player.vimeo.com/video/293891308" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">An FRB’s journey to Earth.</span></figcaption>
</figure>
<p>A fast radio burst leaves a distant galaxy (see the video above), travelling to Earth over billions of years and occasionally passing through clouds of gas in its path. Each time a cloud of gas is encountered, the different wavelengths that make up a burst are slowed by different amounts. </p>
<p>Timing the arrival of the different wavelengths at a radio telescope tells us how much material the burst has travelled through on its way to Earth and allows astronomers to to detect “missing” matter located in the space between galaxies.</p>
<h2>Location, location, location</h2>
<p>There are two places where this matter could be. It could be in the FRB host galaxy, in this case FRBs would be coming from relatively close galaxies. </p>
<p>The other, exciting possibility is that the dispersion is the result of matter in between galaxies. This matter, referred to as the cosmic web, is nearly impossible to study any other way.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/239606/original/file-20181007-72103-1792641.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/239606/original/file-20181007-72103-1792641.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/239606/original/file-20181007-72103-1792641.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=491&fit=crop&dpr=1 600w, https://images.theconversation.com/files/239606/original/file-20181007-72103-1792641.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=491&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/239606/original/file-20181007-72103-1792641.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=491&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/239606/original/file-20181007-72103-1792641.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=617&fit=crop&dpr=1 754w, https://images.theconversation.com/files/239606/original/file-20181007-72103-1792641.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=617&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/239606/original/file-20181007-72103-1792641.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=617&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cosmic web simulation. Galaxies and clusters of galaxies reside on filaments, which are separated by almost empty regions called voids. Surrounding the filaments is diffuse gas that can be probed by fast radio bursts.</span>
<span class="attribution"><span class="source">NASA, ESA, and E Hallman (University of Colorado, Boulder)</span></span>
</figcaption>
</figure>
<p>Figuring out where it resides is another outstanding problem in astronomy. In this case, the FRBs would be coming from more distant objects. </p>
<p><a href="https://astronomy.curtin.edu.au/research/craft/">Our collaboration</a> decided the first step to solve the FRB mystery was to find more of them, and find them quickly.</p>
<p>To do this we decided to go wide and simultaneously stare at as much sky as possible. We used the Australian Square Kilometre Array Pathfinder (<a href="https://www.atnf.csiro.au/projects/askap/index.html">ASKAP</a>), a radio telescope in regional Western Australia that consists of 36, 12-metre dish antennas.</p>
<p>Each antenna is equipped with phased array feeds – radio cameras that would enable searches 36 times wider than could be seen with older technology.</p>
<p>We further widened the searches by pointing the antennas in different directions like a fly’s eye. While these searches would be less sensitive than those that found bursts previously, mostly with the 64-metre Parkes radio telescope in New South Wales, we were relatively confident bright ones existed in sufficient numbers that we should find more. </p>
<p>To conduct the searches, we used six to nine of the ASKAP antennas, while the rest were used for other observing projects. Our first discovery came after just over three days of observing, as <a href="https://theconversation.com/askap-telescope-speeds-up-the-hunt-for-new-fast-radio-bursts-77481">mentioned earlier in The Conversation</a>.</p>
<p>It turns out that we were a bit lucky to find the first one as soon as we did. I was responsible for scheduling the observing, which could run 24/7, and searching the data. </p>
<p>It was an exciting time, and I was very happy to be on the front line and be the first one to spot a new burst. Over the course of the next year, we found the 19 additional bursts reported.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/239602/original/file-20181007-72103-1etdky6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/239602/original/file-20181007-72103-1etdky6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/239602/original/file-20181007-72103-1etdky6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=682&fit=crop&dpr=1 600w, https://images.theconversation.com/files/239602/original/file-20181007-72103-1etdky6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=682&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/239602/original/file-20181007-72103-1etdky6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=682&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/239602/original/file-20181007-72103-1etdky6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=857&fit=crop&dpr=1 754w, https://images.theconversation.com/files/239602/original/file-20181007-72103-1etdky6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=857&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/239602/original/file-20181007-72103-1etdky6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=857&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 ASKAP FRB sample. For each burst, the top panels show what the FRB signal looks like when averaged over all frequencies. The bottom panels show how the brightness of the burst changes with frequency. The bursts are vertical because they have been corrected for dispersion.</span>
<span class="attribution"><span class="source">Ryan Shannon and the CRAFT collaboration</span></span>
</figcaption>
</figure>
<h2>Not the usual FRB</h2>
<p>As the burst count started to rise, we noticed differences with the previously detected ones. The ASKAP bursts have less dispersion than the ones found at Parkes. </p>
<p>This, combined with the fact that the ASKAP bursts are much brighter, indicates that there is a correlation between burst brightness and dispersion. If all the dispersion was coming from within host galaxies, this would not be the case. </p>
<p>We were now able to confidently say that the bursts are experiencing the effects of the diffuse matter in the cosmic web. It also says that bursts are coming from vast distances – from galaxies half way across the universe.</p>
<p>A second key result of our survey is that none of the bursts repeated. As part of our searches, we observed the same regions of sky almost daily, and in total we had spent 12,000 hours (500 days) staring at the positions where we found FRBs.</p>
<p>This makes the bursts different than the best studied, known as <a href="https://www.seti.org/frb-121102-radio-calling-cards-distant-civilization">FRB 121102</a> – aptly called “the repeater” – from which hundreds of pulses have been detected.</p>
<p>Are there two classes of FRBs? It can be scientifically fraught to subdivide phenomena such as FRBs into sub-classes when so few are known. But the differences between the repeater and the rest of the FRBs are starting to become too big to ignore.</p>
<h2>On closer inspection</h2>
<p>The next step for our project is to commission a mode for ASKAP that can be used to localise bursts.</p>
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Read more:
<a href="https://theconversation.com/how-we-found-the-source-of-the-mystery-signals-at-the-dish-41523">How we found the source of the mystery signals at The Dish</a>
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<p>Instead of using the fly’s eye approach, we’ll point all of the antennas in the same direction, search for bursts in real time, and then make an image of the sky for the millisecond the FRB emission was passing by Earth.</p>
<p>We’ll be able tie bursts to host galaxies and accurately measure their distances. By combining the distances with the dispersions we’ll be able to start making a 3D map of the cosmic web. </p>
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<iframe src="https://player.vimeo.com/video/293893521" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Keith Bannister, Jean-Pierre Macquart, and Ryan Shannon describe their work on fast radio bursts (FRBs) and the telescope used for their discovery. Credit: CSIRO.</span></figcaption>
</figure><img src="https://counter.theconversation.com/content/104488/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan Shannon receives funding from the Australian Research Council (ARC) and is a member of the ARC Centre of Excellence for Gravitational-Wave Discovery (OzGrav).</span></em></p>We still don’t know what causes these mysterious Fast Radio Bursts deep in the universe, but we’ve detected a whole new batch of them.Ryan Shannon, Postdoctoral fellow, Swinburne University of Technology, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1016072018-08-17T11:08:18Z2018-08-17T11:08:18ZNew telescope chases the mysteries of radio flashes and dark energy<figure><img src="https://images.theconversation.com/files/232250/original/file-20180816-2897-1biximd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">HIRAX prototype dishes at Hartebeesthoek Astronomy Observatory near Johannesburg.</span> <span class="attribution"><span class="source">Kabelo Kesebonye</span></span></figcaption></figure><p><em>South Africa is becoming one of the world’s most important radio astronomy hubs, thanks in large part to its role as co-host of the Square Kilometre Array (SKA). Now a new telescope is being unveiled that will be built at the SKA South Africa site in the Karoo. The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) <a href="https://bit.ly/2nQdyQT">project</a> is an international collaboration being led by scientists from the University of KwaZulu-Natal. The Conversation Africa chatted to project leader Professor Kavilan Moodley about HIRAX’s scientific goals.</em></p>
<p><strong>What will HIRAX do, and how?</strong></p>
<p>It’s an <a href="http://astronomy.swin.edu.au/cosmos/R/Radio+Interferometer">interferometer array</a> that will be made up of 1024 6-metre dishes. Interferometer arrays are really cool because they combine signals from many telescopes to provide the resolution of a larger telescope. </p>
<p><a href="https://acru.ukzn.ac.za/hirax-postdocs-ad/">HIRAX</a> has two main science goals: to study the evolution of dark energy by tracking neutral hydrogen gas in galaxies, and to detect and localise mysterious radio flashes called fast radio bursts.</p>
<p>Dark energy is a mysterious force driving the accelerated expansion of our universe. HIRAX can study it using a unique cosmic ruler provided by nature, called <a href="http://astronomy.swin.edu.au/cosmos/B/Baryonic+Acoustic+Oscillations">baryon acoustic oscillations</a>. These were generated in the very early universe, which was a hot and dense soup of particles and light. Small irregularities gave rise to sound waves in this primordial soup. </p>
<p>These waves carried matter as they travelled until a time when matter and light separated, distributing matter in a very characteristic pattern. Neutral hydrogen gas is a great tracer of the universe’s matter distribution. This neutral hydrogen emits a signal at 1420 MHz, which is in the range of frequencies used by cellular networks and UHF television channels; the signal gets stretched to lower frequencies as the universe expands.</p>
<p>HIRAX will operate between 400 and 800 MHz allowing it to map neutral hydrogen in the universe between 7 to 11 billion years ago. Studying the characteristics of dark energy during this time has the potential to unravel its properties, as this is a vital time when dark energy became the primary component in the universe and accelerated its expansion.</p>
<p>The second focus area involves mysterious bright, millisecond flashes that scientists call fast radio bursts. Scientists do not know what causes these. They’re also hard to detect and localise since they’re so brief and most telescopes only observe a small region of the sky. </p>
<p>HIRAX’s large field of view will allow it to observe large portions of sky daily – so when the flashes happen, the instrument will be more likely to see them. We expect that it’ll see up to a dozen of these flashes a day; to put that in perspective, only a few dozen in total have ever been observed.</p>
<p>And HIRAX will add the unique capability of being able to figure out exactly where in the sky these fast radio bursts occur, by working with several other Southern African countries to build 8-dish outrigger arrays. These, in combination with the main array, will help localise these bursts to within their hosting galaxies. </p>
<p><strong>It sounds like HIRAX will be collecting huge amounts of data?</strong></p>
<p>It will need to collect large amounts of data at a rate of around 6.5 Terabits per second. That’s comparable to <a href="http://www.africabandwidthmaps.com/">all of Africa’s international bandwidth</a>. For that, HIRAX needs to design and manufacture high precision dishes, receivers and other instrumentation; we’re working with local companies on this challenge.</p>
<p>Then the team will need to figure out smart ways to compress, store and analyse this data. That will require big data hardware and software. </p>
<p>We hope that the design and manufacturing abilities required to equip HIRAX properly will open up many opportunities for local industries in the region around the SKA project. </p>
<p><strong>Is this an SKA project, or entirely separate but using space and technology at the SKA?</strong></p>
<p>The project originated as a response by UKZN and its partner institutions to a call for institutional flagship projects by the National Research Foundation. So it’s independent from the SKA and its precursor, the MeerKAT – but will benefit greatly from the South African investment in the SKA project, which gives it access to excellent infrastructure hosted by the <a href="http://www.ska.ac.za/about/sarao/">South African Radio Astronomy Observatory</a>. </p>
<p>By sharing a location with MeerKAT on the SKA South Africa site, HIRAX will be able to conduct science in “radio-clear” skies across its wide frequency range; <a href="http://www.ska.ac.za/about/astronomy-geographic-advantage-act/">legislation</a> has been introduced to limit radio frequency interference on the SKA SA site. It’s also a great space because it allows access to the southern sky covered by other cosmological surveys and, in turn, more of the galaxy where we’ll find pulsars.</p>
<p>Being part of the “Karoo radio park” will allow HIRAX to add to South Africa’s radio astronomy engineering and infrastructure. This infrastructure and the resulting science will increase South Africa’s reputation as a global leader in radio astronomy. </p>
<p>HIRAX will also contribute to training the next generation of scientists for the SKA; students working on the project will be trained in all aspects of the telescope, from engineering to science. Students who build hardware are also involved in data analysis, which provides a special environment for training upcoming radio astronomy experts.</p>
<p>Finally, there are strong scientific synergies with MeerKAT (which was <a href="http://www.ska.ac.za/media-releases/meerkat-radio-telescope-inaugurated-in-south-africa-reveals-clearest-view-yet-of-center-of-the-milky-way/">officially launched</a> in July 2018). If HIRAX discovers any interesting new pulsars, for instance, MeerKAT can conduct follow-up timing observations at higher frequencies. </p>
<p><em>This article by co-authored by Carolyn Crichton, a technical writer with the HIRAX Project. Before joining the project, she worked for five years at NASA’s Goddard Space Flight Center in the US.</em></p><img src="https://counter.theconversation.com/content/101607/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kavilan Moodley receives funding from the University of KwaZulu-Natal and the National Research Foundation.
The HIRAX project receives funding from the University of KwaZulu-Natal and the Department of Science and Technology via the National Research Foundation.</span></em></p>By sharing a location with the SKA, HIRAX will be able to conduct science in “radio-clear” skies across its wide frequency range.Kavilan Moodley, Associate Professor, University of KwaZulu-NatalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/886682017-12-10T12:10:01Z2017-12-10T12:10:01ZTelescopes in southern Africa will peel back the universe’s secrets from 2018<figure><img src="https://images.theconversation.com/files/197948/original/file-20171206-920-iuzgnt.jpg?ixlib=rb-1.1.0&rect=29%2C139%2C723%2C626&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An image by MeerKAT shows hydrogen gas in M83, a famous spiral galaxy.</span> <span class="attribution"><span class="source">SKA SA</span></span></figcaption></figure><p>One of the world’s largest collaborative science projects is about to enter its most exciting year yet. This will see researchers in a remote stretch of South Africa’s Karoo testing Albert Einstein’s <a href="https://www.space.com/17661-theory-general-relativity.html">general theory of relativity</a>; imaging neutral hydrogen – the building blocks for stars – in the distant universe; and examining galaxies that were formed billions of years ago.</p>
<p>The <a href="https://www.skatelescope.org/frequently-asked-questions/">Square Kilometre Array</a> (SKA) will consist of thousands of dishes and antennas spread over large distances linked together to form one giant telescope. It will be tens of times more sensitive and hundreds of times faster at mapping the sky than today’s best radio telescopes. A precursor to the SKA - the <a href="http://www.ska.ac.za/science-engineering/meerkat/">MeerKAT telescope</a> - is being built right now and remarkable progress has been made in the last 12 months.</p>
<p>MeerKAT will start taking science data with all 64 dishes in early 2018, and there are some really exciting projects planned. I am involved in one of these, a survey called <a href="https://arxiv.org/abs/1709.01901">MIGHTEE</a> or the MeerKAT International GHz Tiered Extragalactic Exploration – we astronomers love convoluted acronyms. </p>
<p>My colleagues and I will be using the MeerKAT dishes to make very deep images in four different patches of the sky covering a total of 10 square degrees; approximately 10 times the size of the full moon. Deeper images mean you can see both intrinsically fainter things, and things that are further away. The fact that we can see things that are further away is more exciting: you can think of this as pushing the horizon further away as you make a deeper image. </p>
<p>Because these images will be so deep we will be able to see bright galaxies up to 13 billion light years away. We will be able to see a galaxy like our Milky Way five billion light years away: the light that we see in these images left that galaxy before our earth had even formed.</p>
<p>With this information we will be able to explore how galaxies like our own Milky Way formed billions of years ago and how they have evolved up to the present day. Understanding this is key to answering long-standing questions like how our galaxy and Earth came to exist.</p>
<p>This is just one of the projects that will be conducted using MeerKAT over the next five years, starting in 2018. It’s work that will bring together more than 300 scientists. </p>
<h2>Collaborating across the world</h2>
<p>The science that’s being conducted at the SKA site is incredibly important. So too is the incredible collaboration that’s required to make the project work. Building such a ground-breaking instrument requires input from scientists and engineers at the cutting edge of their field from across the globe. Such a large collaboration, across many time zones, is logistically challenging but is vital as it enables big scientific breakthroughs to occur.</p>
<p>There are hundreds of scientists – many of them from Africa, and especially South Africa– and more than 100 institutions involved in the SKA project, from 20 countries across six continents. </p>
<p>Engineers are also a critical part of the project. They, too, come from all over the world. The telescope will have <a href="https://theconversation.com/the-square-kilometre-array-finally-has-a-home-or-two-7274">two host sites</a>: one in Western Australia and one in the Northern Cape in South Africa, in the Karoo. Additional dishes will be located in eight other African countries; <a href="https://theconversation.com/ghana-is-boosting-africas-ascent-to-astronomical-heights-82849">Ghana</a>, Zambia, Madagascar, Botswana, Namibia, Kenya, Mauritius and Mozambique. </p>
<p>Such a project brings with it huge technological challenges: once fully completed the telescope will generate data at more than ten times the current global internet traffic. </p>
<p>These challenges are the reason we’re building MeerKAT on the SKA site. It will allow us to test the technology required for the SKA – and, excitingly, it will also do ground-breaking science in its own right. The global science community was blown away when the <a href="https://theconversation.com/africas-meerkat-first-light-images-have-blown-all-expectations-65246">first MeerKAT images</a> were produced in 2016 using just 16 of the eventual 64 dishes. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/197851/original/file-20171205-22962-b2ka11.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/197851/original/file-20171205-22962-b2ka11.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=867&fit=crop&dpr=1 600w, https://images.theconversation.com/files/197851/original/file-20171205-22962-b2ka11.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=867&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/197851/original/file-20171205-22962-b2ka11.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=867&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/197851/original/file-20171205-22962-b2ka11.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1089&fit=crop&dpr=1 754w, https://images.theconversation.com/files/197851/original/file-20171205-22962-b2ka11.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1089&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/197851/original/file-20171205-22962-b2ka11.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1089&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Large scale bubbles and arcs seen with MeerKAT show stellar nurseries (where stars are born) in the Milky Way. For comparison, the previous best image of this star-forming region is shown at the bottom, obtained with the Australia Telescope Compact Array (ATCA).</span>
<span class="attribution"><span class="source">SKA SA</span></span>
</figcaption>
</figure>
<p>Images presented by the SKA team to South Africa’s Minister for Science and Technology, Naledi Pandor, earlier this year using only half of the eventual 64 dishes are particularly impressive. These include images of a distant spiral galaxy; star-forming regions in our own galaxy; and gas in <a href="http://www.messier-objects.com/messier-83-southern-pinwheel-galaxy/">M83</a>, a famous galaxy discovered in Cape Town in 1752.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/197939/original/file-20171206-926-1hwsl5g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/197939/original/file-20171206-926-1hwsl5g.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/197939/original/file-20171206-926-1hwsl5g.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/197939/original/file-20171206-926-1hwsl5g.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/197939/original/file-20171206-926-1hwsl5g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/197939/original/file-20171206-926-1hwsl5g.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/197939/original/file-20171206-926-1hwsl5g.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">First ever radio image (right panel) of a spiral galaxy previously photographed in visible light (left panel). Both the visible light on the left and the radio waves on the right left this galaxy 230 million years ago.</span>
<span class="attribution"><span class="source">SKA SA</span></span>
</figcaption>
</figure>
<h2>Exciting work ahead</h2>
<p>Significant progress has been made since then. All 64 dishes are now in place and the test data being analysed by the commissioning team in Cape Town looks better each day. We are able to make images that are deeper and have a higher resolution than before. </p>
<p>The MIGHTEE survey is just one of the projects that will launch in 2018. I’m involved in it because my work focuses on <a href="https://theconversation.com/radio-galaxies-the-mysterious-secretive-beasts-of-the-universe-64381">radio galaxies</a>. These shoot hugely energetic jets of lightning fast particles out into space, and the MIGHTEE survey will give us an unprecedented view of these galaxies. </p>
<p>We hope to answer questions such as how these powerful jets affect the stars forming in the galaxy, and how these galaxies interact with and are affected by their surroundings. The MeerKAT telescope will bring us one step closer to understanding these complex and mysterious galaxies. </p>
<p>Other upcoming projects include <a href="http://physicstoday.scitation.org/doi/full/10.1063/PT.3.3621">observing pulsars</a> – the spinning cores of collapsed stars which act as very precise clocks – to test Einstein’s general theory of relativity, and <a href="http://www.thunderkat.uct.ac.za/">searching for explosive transients</a>. Pinpointing these short-lived bursts of radio emission will help scientists understand some of the most energetic events in the universe where physics is pushed to the extreme.</p><img src="https://counter.theconversation.com/content/88668/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Imogen Whittam works for the University of the Western Cape. She receives funding from the SKA SA. </span></em></p>A precursor to the Square Kilometre Array- the MeerKAT telescope - is being built right now and remarkable progress has been made in the last 12 months.Imogen Whittam, Post-doctoral researcher in Astrophysics, University of the Western CapeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/851062017-10-16T14:05:24Z2017-10-16T14:05:24ZAfter the alert: radio ‘eyes’ hunt the source of the gravitational waves<figure><img src="https://images.theconversation.com/files/189719/original/file-20171011-5661-q9inuf.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Australia Telescope Compact Array in Narrabri, NSW.</span> <span class="attribution"><span class="source">David Smyth/CSIRO</span>, <span class="license">Author provided</span></span></figcaption></figure><p>At 11:21pm Sydney time on Thursday August 17, 2017, an alert on a private email list informed thousands of astronomers worldwide that the Advanced LIGO-Virgo interferometer had detected another gravitational wave event. </p>
<p>But this time it wasn’t from a binary black hole merger <a href="https://theconversation.com/gravitational-waves-discovered-the-universe-has-spoken-54237">like previous detections</a>: early indications were that this latest wave detection was from two neutron stars merging.</p>
<p>This was really exciting; our chance to see a gravitational wave event with conventional telescopes for the first time. Astronomers had been waiting for this for more than 20 years, ever since the LIGO project started.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/at-last-weve-found-gravitational-waves-from-a-collapsing-pair-of-neutron-stars-85528">At last, we've found gravitational waves from a collapsing pair of neutron stars</a>
</strong>
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<p>By chance, we were both at a conference in Washington DC and so for us the alert arrived just after 9am. People reacted immediately, rapidly emailing colleagues and ducking out to discuss the alert. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/189853/original/file-20171011-28088-148z2xj.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/189853/original/file-20171011-28088-148z2xj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/189853/original/file-20171011-28088-148z2xj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/189853/original/file-20171011-28088-148z2xj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/189853/original/file-20171011-28088-148z2xj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/189853/original/file-20171011-28088-148z2xj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/189853/original/file-20171011-28088-148z2xj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/189853/original/file-20171011-28088-148z2xj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The original alert that was sent out telling astronomers about the detection of gravitational waves.</span>
<span class="attribution"><span class="source">Screengrab</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We started planning our observations immediately: we knew the target area would rise over Australia at about 11am Sydney time.</p>
<p>What followed was two frantic weeks of collaborative research that lead to the first confirmation of radio emission from a gravitational wave event.</p>
<h2>Finding the event: a needle in a haystack</h2>
<p>LIGO-Virgo could only pinpoint the event to an area of about 150 times the full Moon.</p>
<p>But if we could detect electromagnetic radiation (optical or radio waves) then we could pin down the merger’s location to a single galaxy. Australian Radio telescopes have the capability to do this (and not just at night, unlike optical telescopes).</p>
<p>Back on the email list, reports were flooding in. Teams around the world were pointing their telescopes at the target region, scanning the galaxies to see if anything unusual was happening. </p>
<p>At 6am Sydney time we texted Douglas Bock, director of CSIRO Astronomy and Space Science, to let him know we’d be submitting a proposal to observe using the Australia Telescope Compact Array (<a href="https://www.csiro.au/en/Research/Facilities/ATNF/Australia-Telescope-Compact-Array/About-Australia-Telescope-Compact-Array">ATCA</a>) in Narrabri, NSW, that day.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/189329/original/file-20171009-6950-4qxalo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/189329/original/file-20171009-6950-4qxalo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/189329/original/file-20171009-6950-4qxalo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/189329/original/file-20171009-6950-4qxalo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/189329/original/file-20171009-6950-4qxalo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/189329/original/file-20171009-6950-4qxalo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/189329/original/file-20171009-6950-4qxalo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/189329/original/file-20171009-6950-4qxalo.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">Christene Lynch, Dougal Dobie and Tara Murphy in the Australia Telescope Compact Array Science Operations Centre.</span>
<span class="attribution"><span class="source">University of Sydney</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We applied for what is known as Target of Opportunity time: permission to override the scheduled observing and take over the telescope. </p>
<p>We then rang our colleagues <a href="http://sydney.edu.au/science/people/christine.lynch.php">Christene Lynch</a> and <a href="https://theconversation.com/profiles/keith-bannister-221398">Keith Bannister</a>, and PhD student <a href="http://sydney.edu.au/science/physics/sifa/profile_dobie.shtml">Dougal Dobie</a> to ask them to head to the CSIRO Science Operations Centre in Marsfield, Sydney, to observe.</p>
<h2>We start observing</h2>
<p>After a few phone calls and emails, we were allocated the whole day of ATCA observing and we began searching for a radio signal from the merger. We were the first radio telescope to target this event.</p>
<p>Just after midday in Sydney, there was an exciting new development. A new optical source, near the galaxy <a href="http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC+4993">NGC 4993</a> seen in the constellation Hydra, had been detected by the <a href="http://www.lco.cl/">One-Meter Two-Hemisphere collaboration</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/190225/original/file-20171013-3555-1fnr0cy.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/190225/original/file-20171013-3555-1fnr0cy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/190225/original/file-20171013-3555-1fnr0cy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=298&fit=crop&dpr=1 600w, https://images.theconversation.com/files/190225/original/file-20171013-3555-1fnr0cy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=298&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/190225/original/file-20171013-3555-1fnr0cy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=298&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/190225/original/file-20171013-3555-1fnr0cy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=374&fit=crop&dpr=1 754w, https://images.theconversation.com/files/190225/original/file-20171013-3555-1fnr0cy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=374&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/190225/original/file-20171013-3555-1fnr0cy.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=374&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Optical and near-infrared images of the first optical counterpart to a gravitational wave source in the galaxy NGC 4993.</span>
<span class="attribution"><span class="source">1M2H/UC Santa Cruz and Carnegie Observatories/Ryan Foley</span></span>
</figcaption>
</figure>
<p>This was rapidly confirmed by several other groups. </p>
<p>The emails became a deluge. We fired off messages between Washington and Sydney adjusting our observing strategy. Tara set off for the return trip to Sydney as we coordinated and analysed observations from airports and hotels. </p>
<p>We were in constant communication with other groups - there was excitement in the air, but also tension, as people collaborated and competed at the same time.</p>
<h2>What does radio emission tell us?</h2>
<p>A neutron star merger is a complex event. The gravitational waves come from the final orbits just before a black hole is formed.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/EuFxRAYxs2Q?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Detecting radio emission from a neutron star merger.</span></figcaption>
</figure>
<p>The resulting explosion blows the matter from the neutron stars out into space. As this material blasts outwards, it interacts with gas to create a powerful shock that generates radio emission. </p>
<p>Analysing this data tells us what the total energy of the explosion is, and what the surrounding area is like. </p>
<p>This the first time these explosions, which may be responsible for forming heavy elements like gold in the universe, have been definitively identified.</p>
<h2>Finally, a radio detection</h2>
<p>Theoretical models for neutron star mergers predict that radio emission will occur after the emission at other wavelengths. </p>
<p>Nine days after the event, X-ray emission was detected so we kept monitoring the likely host galaxy, NGC 4993, every few days. </p>
<p>Finally, on September 3, our collaborators made a tentative detection of radio waves with the <a href="http://www.vla.nrao.edu/">Very Large Array</a> in New Mexico. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/190282/original/file-20171015-3542-irnlfk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/190282/original/file-20171015-3542-irnlfk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/190282/original/file-20171015-3542-irnlfk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/190282/original/file-20171015-3542-irnlfk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/190282/original/file-20171015-3542-irnlfk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/190282/original/file-20171015-3542-irnlfk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/190282/original/file-20171015-3542-irnlfk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/190282/original/file-20171015-3542-irnlfk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">VLA image showing radio emission from the host galaxy NGC 4993 and the associated transient source (in crosshairs).</span>
<span class="attribution"><span class="source">Reprinted with permission from Hallinan et al., Science (2017)</span></span>
</figcaption>
</figure>
<p>We confirmed their detection the following day, making this something everybody could trust. This was the first time radio waves had ever been detected from a gravitational wave event.</p>
<p>After double- and triple-checking our results with the help of <a href="http://sydney.edu.au/science/people/emil.lenc.php">Emil Lenc</a>, we released an email alert to the community.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-beat-a-cyber-attack-to-see-the-kilonova-glow-from-a-collapsing-pair-of-neutron-stars-85660">We beat a cyber attack to see the 'kilonova' glow from a collapsing pair of neutron stars</a>
</strong>
</em>
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<p>By then, we had been working non-stop for two weeks, juggling the project across time zones as we monitored the unfolding event. Then the race began to write up the results for publication, with our work <a href="http://science.sciencemag.org/lookup/doi/10.1126/science.aap9855">published today in Science</a>.</p>
<p>The past month has been exhilarating but strange, working secretly on embargoed results that had already been <a href="https://www.nature.com/news/rumours-swell-over-new-kind-of-gravitational-wave-sighting-1.22482">partially leaked</a>, and were somewhat of an open secret in much of the astronomy community.</p>
<p>Our radio observations have made an important contribution to understanding an incredible phenomenon. We continue to monitor this event to help understand the details of the explosion.</p><img src="https://counter.theconversation.com/content/85106/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tara Murphy works for the University of Sydney. She received funding from the Australian Research Council, including the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO). </span></em></p><p class="fine-print"><em><span>David Kaplan receives funding from the National Science Foundation and NASA. </span></em></p>All it took was a single email alert to send the world’s astronomers searching for the source of the latest gravitational wave detected.Tara Murphy, Associate Professor and ARC Future Fellow, University of SydneyDavid Kaplan, Associate professor of Physics, University of Wisconsin-MilwaukeeLicensed as Creative Commons – attribution, no derivatives.