tag:theconversation.com,2011:/africa/topics/square-kilometre-array-168/articles
Square Kilometre Array – The Conversation
2024-03-26T00:01:06Z
tag:theconversation.com,2011:article/226397
2024-03-26T00:01:06Z
2024-03-26T00:01:06Z
We went looking for glowing interstellar gas – and stumbled on 49 unknown galaxies
<figure><img src="https://images.theconversation.com/files/583996/original/file-20240325-28-68vtd0.jpg?ixlib=rb-1.1.0&rect=350%2C5%2C1514%2C1385&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Gas detected by MeerKAT (white contours) on top of a three-colour optical image from the DECaLS DR10 survey.</span> <span class="attribution"><a class="source" href="https://academic.oup.com/MNRAS/article-lookup/doi/10.1093/mnras/stae684">Glowacki et al. 2024.</a></span></figcaption></figure><p>Stars are born from huge clouds of mostly hydrogen gas floating in space. Astronomers like me study this gas because it helps us understand how stars and galaxies form and grow.</p>
<p>Hydrogen gas gives off a faint glow that is invisible to human eyes but can be observed with a telescope tuned to detect radio waves. </p>
<p>Recently, my colleagues and I were using a telescope like this – a radio telescope called MeerKAT, in South Africa – to look for hydrogen gas in a particular galaxy. We were only observing for less than three hours, which is quite a short amount of time since the hydrogen glow is so faint. </p>
<p>When we looked at the results, we were in for a huge surprise. Instead of discovering hydrogen gas in the galaxy we aimed at, we spotted it in no less than 49 previously unknown galaxies. Our findings are <a href="https://academic.oup.com/MNRAS/article-lookup/doi/10.1093/mnras/stae684">published</a> in the Monthly Notices of the Royal Astronomical Society.</p>
<h2>Gas in galaxies</h2>
<p>The giant clouds of gas in which stars are born are called nebulae. When stars eventually die, they expel their gas into their surrounding environment, where it eventually cools and forms new nebulae. </p>
<p>Galaxies are like huge factories where the life cycle of stars repeats itself over and over. To properly understand galaxies and how they grow and evolve, astronomers need to consider both the stars and the gas making up the galaxy. </p>
<p>One thing we are particularly interested in is “merger events”, when two galaxies collide and merge into a single, larger galaxy. These events can also impact the gas, and kickstart star formation. </p>
<p>Studying gas can often help us understand a galaxy’s history. Gas often extends far further out than the stars in galaxies. </p>
<p>When we see trails of disturbed gas, it is a classic clue that a recent galaxy merger or interaction has occurred. </p>
<p>But we don’t see galactic gas easily with optical telescopes. Thankfully, radio telescopes are a great tool for finding hydrogen gas.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583828/original/file-20240323-30-pmfayi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of several large white radio dishes standing in a field." src="https://images.theconversation.com/files/583828/original/file-20240323-30-pmfayi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583828/original/file-20240323-30-pmfayi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=324&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583828/original/file-20240323-30-pmfayi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=324&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583828/original/file-20240323-30-pmfayi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=324&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583828/original/file-20240323-30-pmfayi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=408&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583828/original/file-20240323-30-pmfayi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=408&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583828/original/file-20240323-30-pmfayi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=408&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The MeerKAT radio telescope, made up of 64 radio dishes working together to act as a larger telescope.</span>
<span class="attribution"><span class="source">South African Radio Astronomy Observatory (SARAO)</span></span>
</figcaption>
</figure>
<h2>The MeerKAT radio telescope</h2>
<p>The MeerKAT radio telescope in South Africa <a href="https://www.sarao.ac.za/news/sarao-hosts-meerkat-5-years-conference-in-2024/">recently celebrated its fifth birthday</a>. It is one of the “pathfinder” telescopes for the much larger Square Kilometre Array (SKA), a project under construction in South Africa and Australia. </p>
<p>MeerKAT has already achieved some great results, <a href="https://academic.oup.com/mnras/article/501/3/3833/6034001">from detecting giant radio galaxies</a> to studying the <a href="https://www.sarao.ac.za/media-releases/new-meerkat-radio-image-reveals-complex-heart-of-the-milky-way/">centre of our own galaxy</a>, the Milky Way.</p>
<p>There are large survey projects underway with MeerKAT to study the star-forming hydrogen gas in galaxies. These include the <a href="https://www.aanda.org/articles/aa/full_html/2021/02/aa39655-20/aa39655-20.html">MIGHTEE-HI</a> and <a href="https://science.uct.ac.za/laduma">LADUMA</a> surveys, the latter of which will use MeerKAT for more than 3,000 hours searching one part of the sky for hydrogen gas in very distant galaxies. These surveys are specifically focused on finding hydrogen gas and are carefully planned and carried out with that goal in mind.</p>
<p>But that’s not the only way MeerKAT can be used. Astronomers can also pitch ideas for “open time” observations to tackle other science questions or goals. </p>
<p>That’s how this discovery came about. I was hoping to detect hydrogen gas in one specific galaxy with MeerKAT, as it is the most sensitive telescope for these studies. </p>
<p>We did not find hydrogen gas in that galaxy, which was fine. We astronomers don’t always find what we are looking for.</p>
<p>But when I inspected the MeerKAT data, I spotted some gas located away from the target galaxy. So we investigated further. </p>
<p>By using techniques developed for the larger MeerKAT science surveys such as LADUMA, we found a lot more gas. In total, we had 49 detections.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583822/original/file-20240323-16-unrb75.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a field of stars with small loops of coloured lines." src="https://images.theconversation.com/files/583822/original/file-20240323-16-unrb75.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583822/original/file-20240323-16-unrb75.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=587&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583822/original/file-20240323-16-unrb75.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=587&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583822/original/file-20240323-16-unrb75.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=587&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583822/original/file-20240323-16-unrb75.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=738&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583822/original/file-20240323-16-unrb75.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=738&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583822/original/file-20240323-16-unrb75.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=738&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 49 new gas-rich galaxies detected by the MeerKAT radio telescope in South Africa. Each detection is shown as coloured contours, with redder colours indicating more distant gas from us, and bluer colours as closer gas. The background image comes from the optical PanSTARRS survey.</span>
<span class="attribution"><a class="source" href="https://academic.oup.com/MNRAS/article-lookup/doi/10.1093/mnras/stae684">Glowacki et al. 2024</a></span>
</figcaption>
</figure>
<h2>Meet the 49ers</h2>
<p>Each detection of the gas in these galaxies was brand new. In little more than two hours of observing time, MeerKAT had revealed several collections of neighbouring galaxies. </p>
<p>Some of these neighbours are even interacting with each other, as their gas content shows. This was not at all obvious from just looking at the optical images of their stars. </p>
<p>In one case, a galaxy is stealing gas from two companion galaxies, and using it to fuel its own star formation.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583826/original/file-20240323-16-g8ybij.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/583826/original/file-20240323-16-g8ybij.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583826/original/file-20240323-16-g8ybij.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=549&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583826/original/file-20240323-16-g8ybij.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=549&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583826/original/file-20240323-16-g8ybij.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=549&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583826/original/file-20240323-16-g8ybij.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=689&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583826/original/file-20240323-16-g8ybij.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=689&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583826/original/file-20240323-16-g8ybij.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=689&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Examples of individual detections of the gas detected by MeerKAT (white contours) on top of a three-colour optical image from the DECaLS DR10 survey. The gas seen here extends further out than the stars in the galaxies.</span>
<span class="attribution"><a class="source" href="https://academic.oup.com/MNRAS/article-lookup/doi/10.1093/mnras/stae684">Glowacki et al. 2024</a></span>
</figcaption>
</figure>
<p>I’ve informally nicknamed this collection of galaxies the 49ers, <a href="https://www.loc.gov/collections/california-first-person-narratives/articles-and-essays/early-california-history/forty-niners/">a reference to the miners of the 1849 California gold rush</a>. </p>
<p>While MeerKAT took the observations containing the 49 gold nuggets in just a couple of hours, winnowing them out required several other tools. These included <a href="https://www.ilifu.ac.za/about/">the ilifu cloud supercomputer</a>, where we reduced the MeerKAT observations (“data reduction” is a kind of pre-processing that makes the raw observations useful) and a data visualisation tool called <a href="https://cartavis.org/">CARTA</a> which we used for the initial discovery of the 49 new galaxies.</p>
<p>We also examined our data with <a href="https://idavie.readthedocs.io/">iDaVIE-v, a virtual reality software for viewing astronomical datasets in 3D</a>. This software has already been <a href="https://theconversation.com/astronomers-have-discovered-a-rare-polar-ring-galaxy-wrapped-in-a-huge-ribbon-of-hydrogen-213254">used for new discoveries such as polar ring galaxies</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/T_AJlFeoRu0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">VR view of several “49er” gas-rich galaxies.</span></figcaption>
</figure>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/lNuWz_EB9ls?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">VR view of a zoom-in of the 49er galaxies.</span></figcaption>
</figure>
<h2>More gold nuggets to be found</h2>
<p>Finding 49 new galaxies in such a short amount of observation time is quite unusual, even with a telescope as powerful as MeerKAT. However, we know there are more galaxies waiting to be found in upcoming and existing MeerKAT observations. </p>
<p>In some other recent work, our team found traces of gas in more than 80 galaxies (most brand new) across three separate MeerKAT observations. Each of these observations was originally focused on a single galaxy, like the “open time” observation in which we found the 49ers. </p>
<p>What will we find next? We don’t know, but with MeerKAT – and eventually its more powerful successor, the SKA telescope – we’re confident astronomers will turn up plenty more pieces of gold.</p><img src="https://counter.theconversation.com/content/226397/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Marcin Glowacki 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>
An attempt to study gas in one galaxy with the MeerKAT radio telescope detected 49 other galaxies instead.
Marcin Glowacki, Research Associate, Curtin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/218832
2024-01-15T11:39:04Z
2024-01-15T11:39:04Z
20 years ago South Africa had 40 qualified astronomers – all white. How it’s opened space science and developed skills since then
<figure><img src="https://images.theconversation.com/files/568811/original/file-20240111-21-fbk2ef.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Southern African Large Telescope.</span> <span class="attribution"><span class="source">SAAO</span>, <span class="license">Author provided</span></span></figcaption></figure><p>South African astronomy started an important journey two decades ago, when an initiative to attract and train future scientists in the field welcomed its first group of students under the <a href="https://www.star.ac.za/">National Astrophysics and Space Science Programme</a>. </p>
<p>World class facilities have been established during this period, the most notable of which are the <a href="https://www.salt.ac.za/">Southern African Large Telescope</a> (SALT) and the <a href="https://www.sarao.ac.za/science/meerkat/">MeerKAT radio telescope</a>, a precursor to the international <a href="https://www.sarao.ac.za/about/the-project/">Square Kilometre Array</a>. They add to the <a href="https://www.saao.ac.za/">South African Astronomical Observatory</a> and <a href="https://www.sarao.ac.za/about/hartrao/">Hartebeesthoek Radio Observatory</a> which existed already.</p>
<p>The National Astrophysics and Space Science Programme has played a vital role in ensuring that these facilities were not simply operated for the benefit of international partners. It has also contributed individuals with crucial data analysis skills to the country’s growing high-tech workforce.</p>
<p>As astronomers who were part of this journey – organisers, contributors and beneficiaries – we are using the 20th anniversary date to reflect on the programme’s impact and its significance for the country.</p>
<h2>The history</h2>
<p>South Africa’s <a href="https://theconversation.com/south-african-astronomy-has-a-long-rich-history-of-discovery-and-a-promising-future-152777">astronomical history</a>, spanning over 200 years, took a leap in 2000 with the cabinet’s approval for the construction of the Southern African Large Telescope. </p>
<p>Beyond its scientific impact, the idea was to attract and nurture young talent, addressing shortages in scientific and engineering fields in South Africa.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/568554/original/file-20240110-19-8im4w1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Large white dish-shaped structures in a dry landscape." src="https://images.theconversation.com/files/568554/original/file-20240110-19-8im4w1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/568554/original/file-20240110-19-8im4w1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568554/original/file-20240110-19-8im4w1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568554/original/file-20240110-19-8im4w1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568554/original/file-20240110-19-8im4w1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568554/original/file-20240110-19-8im4w1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568554/original/file-20240110-19-8im4w1.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">MeerKAT.</span>
<span class="attribution"><span class="source">South African Radio Astronomy Observatory (SARAO)</span></span>
</figcaption>
</figure>
<p>At the time, there were only about 40 astronomers with PhDs in the country. All were white. This was the result of the racially skewed education system during the apartheid era.</p>
<p>In 2001, astronomers began preparing for SALT and future projects. The <a href="https://theconversation.com/in-australia-and-south-africa-construction-has-started-on-the-biggest-radio-observatory-in-earths-history-195818">Square Kilometre Array</a> (SKA) emerged as an opportunity to host a big international radio telescope which could, among other things, investigate the beginnings of the Universe. Unfortunately the shortage of South African astronomers posed a threat to the success of the two projects, and to Africa’s participation.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-visionary-scientist-bernie-fanaroff-put-african-astronomy-on-the-map-183248">How visionary scientist Bernie Fanaroff put African astronomy on the map</a>
</strong>
</em>
</p>
<hr>
<h2>Developing a pipeline</h2>
<p>Becoming a professional astronomer requires a PhD in astronomy, physics, or a related subject. It takes about 10 years to qualify after completing secondary school. At that time <a href="https://repository.hsrc.ac.za/handle/20.500.11910/7864">fewer than 1% of black school leavers qualified to study for a BSc in physics or astronomy</a>. </p>
<p>It became clear that universities needed to start co-operating if the landscape was to change. The country’s small astronomical community was spread across eight universities and two national facilities. </p>
<p>A decision was taken to pool resources to establish the National Astrophysics and Space Science Programme. In this way, university lecturers and professionals at the national observatories could all contribute to teaching, while students could choose from a wide range of research projects. </p>
<p>This collaboration, including the organisation that became the <a href="https://www.sansa.org.za/">South African National Space Agency</a>, focused on guiding students through honours and master’s degrees. It emphasised cooperation over institutional interests and targeted young scientists, especially those from previously disadvantaged communities.</p>
<p>The primary objectives were clear: </p>
<ul>
<li><p>attract students post-Bachelor of Science</p></li>
<li><p>recruit from other countries in Africa</p></li>
<li><p>entice school leavers into BSc physics programmes</p></li>
<li><p>make participation in the programme a selling point for all participating universities. </p></li>
</ul>
<p>Bursaries covering basic needs were crucial to attract smart students from disadvantaged backgrounds. Funding from private foundations, particularly from the Ford Foundation, the Mellon Foundation and the Canon Collins Trust, added to very basic grants from the <a href="https://www.nrf.ac.za/">National Research Foundation</a>. </p>
<p>Today, the government’s Department of Science and Innovation is the primary funder. </p>
<p>Grants are adequate, rather than generous. Nevertheless, students have developed successful careers through the programme, transforming astronomy and space science in South Africa and beyond.</p>
<p>Programme participant Pfesesani van Zyl <a href="https://nassp-at-20.saao.ac.za/testimonials/">said</a>:</p>
<blockquote>
<p>The journey to SALT was a truly transformative experience for me … As a child growing up in a small town, the notion of pursuing a career in astronomy seemed like an unattainable dream, especially as a female of colour … However, that visit shattered those limiting beliefs.</p>
</blockquote>
<p>As former beneficiary <a href="https://theconversation.com/profiles/roger-deane-1344758">Roger Deane</a>, now a professor at the University of the Witwatersrand, put it, the programme was pivotal in</p>
<blockquote>
<p><a href="https://nassp-at-20.saao.ac.za/testimonials/">giving us exposure to the leading astronomers in the country … This was extremely helpful in assessing astronomy as a career.</a></p>
</blockquote>
<h2>Track record</h2>
<p>By mid 2023, the National Astrophysics and Space Science Programme had produced 439 honours graduates and 215 master’s degrees in astrophysics and space science. Another 27 honours and 21 master’s students are set to graduate shortly, and similar numbers of students will complete their degrees in 2024. </p>
<p>A 2023 survey of programme graduates had 230 respondents, including 53 graduates from 19 other African countries. The largest numbers were from Uganda, Madagascar, Ethiopia, Kenya, Zambia and Sudan. Many have returned home.</p>
<p>Former participant <a href="https://africanscientists.africa/business-directory/nyamai/">Miriam Nyamai</a> <a href="https://nassp-at-20.saao.ac.za/testimonials/">said</a>:</p>
<blockquote>
<p>Collaboration with international researchers through the programme enabled me to do world-class research, attend international conferences, and give talks on my work.</p>
</blockquote>
<h2>Impact</h2>
<p>The impact of the programme’s graduates extends far beyond academia. Many have embarked on successful careers across diverse sectors, including industry, education and government. </p>
<p>Graduates have participated in exciting astronomical discoveries. These include producing the <a href="https://theconversation.com/african-scientists-and-technology-could-drive-future-black-hole-discoveries-183139">first images of black holes</a> with the Event Horizon Telescope, finding some of the most distant galaxies yet known, and using SALT to investigate the remnants of some very massive binary stars and unusual active black holes at great distances. </p>
<p>The work of many individuals has been recognised by national and international bodies and programme graduates are in key teaching and research posts in South African universities. Over 30 are employed in the astronomy national facilities and the national space agency, while some have prestigious positions elsewhere in the world. South Africa now has over 200 qualified astronomers, not all of them from the National Astrophysics and Space Science Programme.</p>
<p>Nevertheless, it remains a challenge to fill vacant astronomer posts in South Africa. Many factors contribute to this, including funding, opportunities outside academia, and the lack of clear career paths. The National Astrophysics and Space Science Programme can only ever be part of the solution to these complex systemic problems.</p>
<h2>Future directions</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/562413/original/file-20231129-31-7ta15v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/562413/original/file-20231129-31-7ta15v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/562413/original/file-20231129-31-7ta15v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=458&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562413/original/file-20231129-31-7ta15v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=458&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562413/original/file-20231129-31-7ta15v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=458&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562413/original/file-20231129-31-7ta15v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=575&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562413/original/file-20231129-31-7ta15v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=575&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562413/original/file-20231129-31-7ta15v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=575&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">NASSP students visit the SAAO 1-m telescope.</span>
<span class="attribution"><span class="source">SAAO</span></span>
</figcaption>
</figure>
<p>The programme has evolved since its establishment. Students now have to navigate extensive volumes of intricate data of different kinds, from various sources. Machine learning and artificial intelligence are indispensable. Students must know what these tools can and cannot do as they push the boundaries of our comprehension. This is a challenge for both students and their mentors.</p>
<p>The main obstacle now lies, as it did 20 years ago, in helping university staff to collaborate across institutions in such a way that their work is recognised and rewarded. This requires senior administrators to understand that inter-university collaborations are an investment in their own institutions as well as in the advancement of South African science.</p>
<p><em>To commemorate the 20th anniversary of the National Astrophysics and Space Science Programme, a two-day <a href="https://nassp-at-20.saao.ac.za/">symposium</a> has been organised in January 2024, hosted at the University of Cape Town in South Africa.</em></p><img src="https://counter.theconversation.com/content/218832/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patricia Ann Whitelock receives research funding from the National Research Foundation and the University of Cape Town.. </span></em></p><p class="fine-print"><em><span>Daniel Cunnama receives funding from the National Research Foundation. He works for the South African Astronomical Observatory, a business unit of the National Research Foundation.</span></em></p><p class="fine-print"><em><span>Rosalind Skelton receives funding from the National Research Foundation. She works for the South African Astronomical Observatory, a business unit of the National Research Foundation. </span></em></p>
The astronomical community has thrived and world-class astronomical facilities have been established in South Africa.
Patricia Ann Whitelock, Former director of SAAO and honorary professor at UCT, South African Astronomical Observatory
Daniel Cunnama, Science Engagement Astronomer, South African Astronomical Observatory
Rosalind Skelton, SALT Astronomer and Head of Research at the South African Astronomical Observatory, National Research Foundation
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/215250
2023-10-13T04:04:14Z
2023-10-13T04:04:14Z
Starlink satellites are ‘leaking’ signals that interfere with our most sensitive radio telescopes
<figure><img src="https://images.theconversation.com/files/553608/original/file-20231013-27-sjapd4.jpeg?ixlib=rb-1.1.0&rect=17%2C29%2C3976%2C2628&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://noirlab.edu/public/images/ann21021c/">NOIRLab</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>When I was a child in the 1970s, seeing a satellite pass overhead in the night sky was a rare event. Now it is commonplace: sit outside for a few minutes after dark, and you can’t miss them.</p>
<p>Thousands of satellites have been launched into Earth orbit over the past decade or so, with tens of thousands more <a href="https://planet4589.org/space/con/conlist.html">planned</a> in coming years. Many of these will be in “mega-constellations” such as Starlink, which aim to cover the entire globe.</p>
<p>These bright, shiny satellites are putting at risk our connection to the cosmos, which has been important to humans for countless millennia and has already been <a href="https://education.nationalgeographic.org/resource/light-pollution/">greatly diminished</a> by the growth of cities and artificial lighting. They are also posing a problem for astronomers – and hence for our understanding of the universe.</p>
<p>In <a href="https://arxiv.org/abs/2309.15672">new research</a> accepted for publication in Astronomy and Astrophysics Letters, we discovered Starlink satellites are also “leaking” radio signals that interfere with radio astronomy. Even in a “<a href="https://www.industry.gov.au/science-technology-and-innovation/space-and-astronomy/co-hosting-ska-telescope/australian-radio-quiet-zone-wa">radio quiet zone</a>” in outback Western Australia, we found the satellite emissions were far brighter than any natural source in the sky. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0Aj2lmQBSAg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An animation showing the increase in the number of satellites in Earth orbit, over the course of the space age, so far.</span></figcaption>
</figure>
<h2>A problem for our understanding of the universe</h2>
<p>Our team at Curtin University used <a href="https://arxiv.org/abs/2112.00908?context=astro-ph">radio telescopes in Western Australia</a> to examine the radio signals coming from satellites. </p>
<p>We found expected radio transmissions at designated and licensed radio frequencies, used for communication with Earth. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/TT1hJ2NOZQo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Starlink satellites emit bright flashes of radio transmission (shown in blue) at their allocated frequency of 137.5 MHz.</span></figcaption>
</figure>
<p>However, we also found signals at unexpected and unintended frequencies. </p>
<p>We found these signals coming from many Starlink satellites. It appears the signals may originate from electronics on board the spacecraft.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FISUgjrCAi4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Here we see constant, bright emissions from Starlink satellites at 159.4 MHz, a frequency not allocated to satellite communications.</span></figcaption>
</figure>
<p>Why is this an issue? Radio telescopes are incredibly sensitive, to pick up faint signals from countless light-years away. </p>
<p>Even an extremely weak radio transmitter hundreds or thousands of kilometres away from the telescope appears as bright as the most powerful cosmic radio sources we see in the sky. So these signals represent a serious source of interference.</p>
<p>And specifically, the signals are an issue at the location where we tested them: the <a href="https://www.csiro.au/en/about/facilities-collections/atnf/mro">site in WA</a> where construction has already begun for part of the biggest radio observatory ever conceived, the <a href="http://www.skatelescope.org">Square Kilometre Array</a> (SKA). This project involves 16 countries, has been in progress for 30 years, and will cost billions of dollars over the next decade.</p>
<p>Huge effort and expense has been invested in locating the SKA and other astronomy facilities a long way away from humans. But satellites present a new threat in space, which can’t be dodged.</p>
<h2>What can we do about this?</h2>
<p>It’s important to note satellite operators do not appear to be breaking any rules. The regulations around use of the radio spectrum are governed by the <a href="https://www.itu.int/pub/R-HDB-22-2013">International Telecommunications Union</a>, and they are complex. At this point there is no evidence Starlink operators are doing anything wrong.</p>
<p>The radio spectrum is crucial for big business and modern life. Think mobile phones, wifi, GPS and aircraft navigation, and communications between Earth and space. </p>
<p>However, the undoubted benefits of space-based communications – such as for globally accessible fast internet connections – are coming into conflict with our ability to see and explore the universe. (There is some irony here, as wifi in part owes its <a href="https://en.wikipedia.org/wiki/Wi-Fi">origins</a> to radio astronomy.)</p>
<p>Regulations evolve slowly, while the technologies driving satellite constellations like Starlink are developing at lightning speed. So regulations are not likely to protect astronomy in the near term.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-many-satellites-are-orbiting-earth-166715">How many satellites are orbiting Earth?</a>
</strong>
</em>
</p>
<hr>
<p>But in the course of our research, we have had a very positive engagement with SpaceX engineers who work on the Starlink satellites. It is likely that the goodwill of satellite operators, and their willingness to mitigate the generation of these signals, is the key to solving the issue.</p>
<p>In response to earlier criticisms, SpaceX has made <a href="https://arxiv.org/abs/2306.06657">improvements</a> to the amount of sunlight Starlink satellites reflect, making them one-twelfth as bright in visible light as they used to be.</p>
<p>We estimate emissions in radio wavelengths will need to be reduced by a factor of a thousand or more to avoid significant interference with radio astronomy. We hope these improvements can be made, in order to preserve humanity’s future view of the universe, the fundamental discoveries we will make, and the future society-changing technologies (like wifi) that will emerge from those discoveries.</p><img src="https://counter.theconversation.com/content/215250/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven Tingay is affiliated with the Australian Labor Party. </span></em></p>
Starlink satellites emit bright, unintended and unexpected signals that can be detected by radio telescopes.
Steven Tingay, John Curtin Distinguished Professor (Radio Astronomy), Curtin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/201341
2023-09-21T21:56:09Z
2023-09-21T21:56:09Z
Canada’s participation in the world’s largest radio telescope means new opportunities in research and innovation
<figure><img src="https://images.theconversation.com/files/548371/original/file-20230914-8809-zchqj4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2000%2C1000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An artist's impression of the Square Kilometre Array Observatory, the largest of its kind in the world.</span> <span class="attribution"><a class="source" href="https://skao.canto.global/v/SKAOLibrary/album/G20QH?viewIndex=1&column=image&id=m02qd2lp390bd092m1d4a9734g">(SKAO)</a></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/canadas-participation-in-the-worlds-largest-radio-telescope-means-new-opportunities-in-research-and-innovation" width="100%" height="400"></iframe>
<p>Canada is about to <a href="https://www.canada.ca/en/national-research-council/news/2023/01/canada-announces-intention-to-become-full-member-of-international-skao-radio-astronomy-project.html">become a member</a> of the <a href="https://www.skao.int/en">Square Kilometre Array Observatory (SKAO)</a> — the world’s next giant radio telescope. This is a win for all Canadians, not just astronomers. </p>
<p>SKAO is a radio telescope made up of thousands of individual elements over vast areas. Its two remote sites are located, in partnership with <a href="https://www.skao.int/en/partners/429/local-and-indigenous-communities">local and Indigenous communities</a>, in the <a href="https://www.britannica.com/place/Karoo">Karoo desert region of South Africa</a> and the traditional lands of the <a href="https://research.csiro.au/ska/location/">Wajarri Yamaji in outback Western Australia</a>. </p>
<p>An international partnership that will operate the observatory includes 16 countries located on five continents.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/Cl895XftKK6","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Radio observations</h2>
<p>Observing the sky with radio telescopes is not just (or even mostly) about looking for aliens. Electromagnetic radiation at radio wavelengths is produced by some of the most interesting and mysterious objects in the universe. These range from the supermassive black holes at the hearts of distant galaxies to pulsars that spin at dizzying rates like the fastest lighthouses, to the baffling explosions that produce <a href="https://www.dunlap.utoronto.ca/observational-research/time-domain-science/fast-radio-bursts/">fast radio bursts</a>. </p>
<p>To detect these faint signals when they reach Earth, we need many sophisticated antennas spread over large geographical areas, and located in places far from human-generated interference. </p>
<h2>Canadian involvement</h2>
<p>Canadian scientists are involved in many international projects, including the <a href="https://home.cern/science/accelerators/large-hadron-collider">Large Hadron Collider in Geneva, Switzerland</a> and <a href="https://www.snolab.ca/">SNOLAB underground laboratory in Lively, Ont.</a>. </p>
<p>The Canadian Astronomical Society makes recommendations on telescope participation through a <a href="https://casca.ca/?page_id=11499">decade long range plan</a> in which the professional astronomy community considers its priorities. Full participation in the SKA was the highest priority among large projects of the most recent plan <a href="https://casca.ca/?page_id=11499">that covers 2020 to 2030</a>. </p>
<p>Canada has already been a key partner in <a href="https://www.skao.int/en/partners/prospective-members/388/canada#__otpm0">the SKA project for over 20 years</a>, making contributions to both the technical and scientific designs. There is no other existing or planned telescope like the SKAO, and not participating would have meant that Canadian astronomers would miss out. </p>
<h2>Canadian leadership</h2>
<p>Canadian astronomy, despite its small size, is a world leader. We already conduct research with radio astronomy facilities such as the <a href="https://chime-experiment.ca/en">CHIME</a> experiment near Penticton, B.C., <a href="https://almaobservatory.org/en/home/">Atacama Large Millimeter/submillimeter Array</a> in Chile and the <a href="https://science.nrao.edu/facilities/vla">Jansky Very Large Array</a> in New Mexico. Participation in the SKAO will allow us to keep making new discoveries, thanks to one of the largest Canadian investments in astronomy to date.</p>
<figure class="align-center ">
<img alt="a blue-lit circular device" src="https://images.theconversation.com/files/548372/original/file-20230914-19-joy01g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548372/original/file-20230914-19-joy01g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=368&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548372/original/file-20230914-19-joy01g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=368&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548372/original/file-20230914-19-joy01g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=368&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548372/original/file-20230914-19-joy01g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=463&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548372/original/file-20230914-19-joy01g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=463&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548372/original/file-20230914-19-joy01g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=463&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Large Hadron Collider at the European Organization for Nuclear Research where the Higgs boson was detected in 2012.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Canada’s membership in the SKAO will allow Canadian companies to bid on shares of the work to be done for this billion-dollar mega science project. <a href="https://www.skao.int/en/partners/prospective-members/388/canada#__otpm5">Technologies developed for the project</a> will include computer hardware for digital signal processing and antenna dishes that can be mass produced of composite materials. These technologies may have applications in other industries. There is also the opportunity to strengthen Canada’s innovation culture and international reputation as a technology leader. </p>
<p>Once at full operation, the SKAO will produce a data firehose: <a href="https://www.skao.int/en/explore/big-data">300 petabytes</a>, or about half a million typical laptop hard drives, per year. Developing the computer hardware and software for processing the SKA data will be another technological win for Canada: the algorithms and know-how needed can be adapted for big data applications elsewhere, from climate modelling to epidemiological research.</p>
<h2>Future generations</h2>
<p>SKAO is not just another radio telescope. Construction will be <a href="https://www.space.com/square-kilometer-array-observatory-construction-begins">completed in 2029</a>, with significant Canadian contributions. Membership in SKAO will also attract and train the next generation of Canadian scientists and engineers. </p>
<p>The excitement of space attracts many youth to STEM careers, and those who choose to study astronomy will have the opportunity to work with cutting-edge hardware and vast amounts of data. Some of those graduates will go on to work in astronomy research, while others will apply their skills to careers in finance, health care or environmental monitoring and protection. This will help build Canada’s capacity for innovation in a technologically driven future.</p><img src="https://counter.theconversation.com/content/201341/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Pauline Barmby receives funding from the Natural Sciences and Engineering Research Council and the Canadian Space Agency and was co-chair of the Canadian Astronomical Society’s 2020 Long Range Plan panel.</span></em></p>
Canada’s partnership in the world’s largest radio telescope, located in South Africa and Australia, creates new opportunities for research, but the benefits go beyond astronomy.
Pauline Barmby, Professor, Physics & Astronomy, Western University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/211604
2023-08-31T14:09:55Z
2023-08-31T14:09:55Z
How our ancestors viewed the sky: new film explores both indigenous and modern cosmology
<p>Something remarkable is happening in a remote part of South Africa’s Northern Cape province, in a semi-desert area called the Karoo. In the past 15 years 64 radio receiving dishes have appeared on the landscape. These constitute the <a href="https://www.sarao.ac.za/gallery/meerkat/">MeerKAT telescope</a>, a precursor to the <a href="https://www.skao.int/en/about-us/skao">Square Kilometre Array Observatory</a> (SKAO), which will – when it is completed and fully functional in 2030 – be the world’s largest radio telescope.</p>
<p>The SKAO will receive signals emanating from the dark regions between the stars and galaxies. This data, studied by <a href="https://www.skao.int/en/resources/what-radio-astronomy">radio astronomers</a>, has the capacity to inform us about dark matter and could change our conception of the universe irrevocably.</p>
<p>In his new, award-winning documentary, <a href="https://www.youtube.com/watch?v=z2g7eGjWGCk">!Aitsa</a>, filmmaker Dane Dodds explores the intellectual background and science of the SKAO alongside indigenous conceptions of the cosmos held by ancient <a href="http://lloydbleekcollection.cs.uct.ac.za/">ǀXam San people</a> and their Afrikaans-speaking descendants living in the Karoo today. As the film’s advisor I saw my task as bringing into focus the hidden assumptions that must be recognised in any encounter between knowledge, traditions and cosmology.</p>
<p>!Aitsa (a South African exclamation of praise or surprise) explores the SKAO’s approach to understanding the universe through big data made comprehensible by the techniques of empirical science, machine learning, artificial intelligence and instrumentation. The film also examines <a href="https://www.tandfonline.com/doi/abs/10.1080/08949468.2023.2168962?journalCode=gvan20">Karoo star-lore</a> as it is shared and spread by an interwoven tapestry of oral traditions. Conventional ideas about the <a href="https://www.tandfonline.com/doi/abs/10.1080/01436597.2018.1447374">nature of science</a> are challenged and the dominant structures of <a href="https://www.tandfonline.com/doi/abs/10.1080/02533952.2020.1850626">knowledge creation</a> are questioned as a result.</p>
<p>To the ǀXam and San people, being in the world as a person includes “the sky’s things” – an understanding of and deep connection with the cosmos. In an age progressively dominated by digital and automated knowledge it was important that the film hold space for this notion.</p>
<h2>Inflected with star-lore</h2>
<p>Through <a href="https://scholar.google.com/citations?user=dBUudaAAAAAJ&hl=en">my own research</a> in the fields of archaeoacoustics, rock art and oral tradition I have come to understand that there is a profound multiplicity of connections within the ǀXam knowledge tradition. In a ǀXam conception of the universe there is no alienating distance between inner and outer, person, stars and space. That’s because their cultural understanding of reciprocities encourages ecological and cosmic connection. </p>
<p>!Aitsa strives to express astronomy as a lived-body experience. One person interviewed in the film says:</p>
<blockquote>
<p>When I look up into the sky and look at how my star is positioned, and look up at the star’s direction, I know which way to walk.</p>
</blockquote>
<p>Another describes the Milky Way as being “right at the centre of a person’s spirituality.”</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/z2g7eGjWGCk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The trailer for !Aitsa.</span></figcaption>
</figure>
<h2>Animism and animation</h2>
<p>The instruments of modern science deliver facts, innovation and technical advancement. But all this comes with societal entanglements and colonial dynamics, a part of the <a href="https://archive.unu.edu/unupress/unupbooks/uu05se/uu05se00.htm">intellectual history</a> of scientific endeavour that assumes authority and stands aloof from the kinds of sensory perceptions and lived experience that are central to ǀXam San cosmology.</p>
<p>!Aitsa investigates a modern pre-disposition that considers <a href="https://www.journals.uchicago.edu/doi/pdf/10.1086/200061">animistic knowledge</a> and reasoning as inherently flawed. Animism is the notion that any living thing has a distinct spiritual essence. It’s a mistake to dismiss ǀXam cultural expression as a mythology that is intrinsically animistic and therefore quaint.</p>
<p>The ǀXam and San people are known as “<a href="https://books.google.co.za/books/about/People_of_the_Eland.html?id=D_wwAQAAIAAJ&redir_esc=y">the people of the eland</a>” and so, to illustrate the way their beliefs animate “things”, an eland antelope is a key character in !Aitsa. The animal’s presence compels the viewer to consider the importance of relationship and relatedness. </p>
<h2>Soundscapes</h2>
<p>Sound plays a crucial role in the film, and was another opportunity to showcase an element of |Xam San culture. The soundtrack (you can hear a preview <a href="https://soundcloud.com/s_i_l_v_a_n/aitsa-film-ost-preview">here</a>) draws on composer Simon Kohler’s musical creativity and the archaeoacoustic research I have done on lithophones, otherwise known as gong rocks, which produce sounds not dissimilar to that of a bell when it is struck.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-the-music-of-an-ancient-rock-painting-was-brought-to-life-185475">How the music of an ancient rock painting was brought to life</a>
</strong>
</em>
</p>
<hr>
<p>Sound is the most ephemeral and transitory of presences but in the film the gong rock sound is a thread linking voices and images, past and present. Collecting the sound required two trips into the Karoo. There we recorded a variety of rock sounds – deep bass-vibrations through to light metallic tinkles. We brought these recordings back into the Cape Town sound studio where the sound was “composed” to create the soundtrack that viewers will hear throughout the film.</p>
<h2>What next?</h2>
<p><a href="https://www.aitsafilm.com/">!Aitsa</a> had its world premiere at <a href="https://cphdox.dk/film/aitsa/">CPH:DOX</a> in Denmark in 2023, with sold out screenings and <a href="https://mubi.com/en/lists/cph-dox-2023-best-to-worst">rave reviews</a>. The film won the Grand Prize at Estonia’s <a href="https://www.chaplin.ee/">Pärnu International Film Festival</a> and was voted Best of the Fest at the Encounters Film Festival in Cape Town. !Aitsa is selected to screen in Canada at <a href="https://planetinfocus.org/">planetinfocus</a> and in October 2023 at the <a href="https://psff.cz/">Prague Science Film Fest</a> and is up for selection at the <a href="https://www.idfa.nl/en">idfa Festival</a> in the Netherlands in November.</p>
<p>In 2024 !Aitsa will go on a road trip, visiting remote places in the Karoo where the film will be screened to audiences who do not have the means for or access to cinemas. </p>
<p>We also hope to take the film to Australia so that the Wajarri Yamaji Aboriginal people can see, listen and connect with their counterparts in the Karoo. This is an important connection because the Wajarri Yamaji live in the Murchison region in Western Australia where the low-frequency component of the SKAO is <a href="https://www.skao.int/en/partners/skao-members/133/australia">currently under construction</a>.</p><img src="https://counter.theconversation.com/content/211604/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neil Rusch does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
To the ǀXam and San people, being in the world as a person includes “the sky’s things” - an understanding of and deep connection with the cosmos.
Neil Rusch, Research Associate, University of the Witwatersrand
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/199688
2023-04-05T15:45:25Z
2023-04-05T15:45:25Z
Astronomers used machine learning to mine data from South Africa’s MeerKAT telescope: what they found
<figure><img src="https://images.theconversation.com/files/515439/original/file-20230315-28-t0q61o.jpg?ixlib=rb-1.1.0&rect=94%2C111%2C715%2C558&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">SAURON: radio intensity (purple) from MeerKAT overlaid on an optical image from the Dark Energy Survey.</span> <span class="attribution"><span class="source">Michelle Lochner / The Dark Energy Survey Collaboration 2005</span></span></figcaption></figure><p>New telescopes with unprecedented sensitivity and resolution are being unveiled around the world – and beyond. Among them are the <a href="https://giantmagellan.org/">Giant Magellan Telescope</a> under construction in Chile, and the <a href="https://webb.nasa.gov/">James Webb Space Telescope</a>, which is parked a million and a half kilometres out in space. </p>
<p>This means there is a wealth of data available to scientists that simply wasn’t there before. The raw data off just a single observation from the <a href="https://www.sarao.ac.za/science/meerkat/">MeerKAT radio telescope</a> in South Africa’s Northern Cape province can measure a terabyte. That’s enough to fill a laptop computer’s hard drive. <a href="https://theconversation.com/a-big-moment-for-africa-why-the-meerkat-and-astronomy-matter-99714">MeerKAT</a> is an array of 64 large antenna dishes. It uses radio signals from space to study the evolution of the universe and everything it contains – galaxies, for example. Each dish is said to generate as much <a href="https://www.sarao.ac.za/science/meerkat/about-meerkat/">data in one second</a> as you’d find on a DVD.</p>
<p><a href="https://www.britannica.com/technology/machine-learning">Machine learning</a> is helping astronomers to work through this data quickly and more accurately than poring over it manually. Perhaps surprisingly, despite increasing reliance on computers, up until recently the discovery of rare or new astrophysical phenomena has completely relied on human inspection of the data. </p>
<p>Machine learning is essentially a set of algorithms designed to automatically learn patterns and models from data. Because we astronomers aren’t sure what we’re going to find – we don’t know what we don’t know – we also design algorithms to look out for anomalies that don’t fit known parameters or “labels”.</p>
<p>This approach allowed my colleagues and I <a href="https://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/stad074/6985618?redirectedFrom=fulltext">to spot</a> a previously overlooked object in data from MeerKAT. It sits some seven billion light years from Earth (a light year is a measure of how far light would travel in a year). From what we know of the object so far, it has many of the makings of what’s known as an Odd Radio Circle (ORC). </p>
<p>Odd Radio Circles are identifiable by their <a href="https://astronomy.com/news/2022/05/understanding-the-origins-of-orcs-odd-radio-circles">strange, ring-like structure</a>. Only a handful of these circles have been detected since the first discovery in 2019, so not much is known about them yet.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/combined-power-of-two-telescopes-is-helping-crack-the-mystery-of-eerie-rings-in-the-sky-180595">Combined power of two telescopes is helping crack the mystery of eerie rings in the sky</a>
</strong>
</em>
</p>
<hr>
<p>In a new <a href="https://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/stad074/6985618?redirectedFrom=fulltext">paper</a> we outline the features of our potential Odd Radio Circle, which we’ve named SAURON (a Steep and Uneven Ring Of Non-thermal Radiation). SAURON is, to our knowledge, the first scientific discovery made in MeerKAT data with machine learning. (There have been a handful of other discoveries assisted by machine learning in astronomy.)</p>
<p>Not only is discovering something new incredibly exciting, new discoveries are critical for challenging our understanding of the <a href="https://www.britannica.com/science/Cosmos-astronomy">cosmos</a>. These new objects may match our theories of how galaxies form and evolve, or we may need to change how we see the universe. New discoveries of anomalous astrophysical objects help science to make progress. </p>
<h2>Identifying anomalies</h2>
<p>We spotted SAURON in data from the <a href="https://arxiv.org/abs/2111.05673">MeerKAT Galaxy Cluster Legacy Survey</a>. The survey is a programme of observations conducted with South Africa’s MeerKAT telescope, a precursor to the <a href="https://www.skao.int/">Square Kilometre Array</a>. The array is a global project to build the world’s largest and most sensitive radio telescope within the coming decade, co-located in South Africa and Australia. </p>
<p>The survey was conducted between June 2018 and June 2019. It zeroed in on some 115 galaxy clusters, each made up of hundreds or even thousands of galaxies.</p>
<p>That’s a lot of data to sift through – which is where machine learning comes in. </p>
<p>We developed and used a coding framework which we called <a href="https://arxiv.org/abs/2010.11202">Astronomaly</a> to sort through the data. Astronomaly ranked unknown objects according to an anomaly scoring system. The human team then manually evaluated the 200 anomalies that interested us most. Here, we drew on vast collective expertise to make sense of the data. </p>
<p>It was during this part of the process that we identified SAURON. Instead of having to look at 6,000 individual images, we only had to look through the first 60 that Astronomaly flagged as anomalous to pick up SAURON. </p>
<p>But the question remains: what, exactly, have we found?</p>
<h2>Is SAURON an Odd Radio Circle?</h2>
<p>We know very little about Odd Radio Circles. It is currently thought that their bright, blast-like emission is the wreckage of a huge <a href="https://theconversation.com/odd-radio-circles-that-baffled-astronomers-are-likely-explosions-from-distant-galaxies-178290">explosion</a> in their host galaxies.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/517713/original/file-20230327-23-vb272r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Purple roughly circular shape on dark background" src="https://images.theconversation.com/files/517713/original/file-20230327-23-vb272r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/517713/original/file-20230327-23-vb272r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=446&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517713/original/file-20230327-23-vb272r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=446&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517713/original/file-20230327-23-vb272r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=446&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517713/original/file-20230327-23-vb272r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=561&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517713/original/file-20230327-23-vb272r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=561&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517713/original/file-20230327-23-vb272r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=561&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">SAURON.</span>
<span class="attribution"><span class="source">Michelle Lochner</span></span>
</figcaption>
</figure>
<p>The name SAURON captures the fundamentals of the object’s make-up. “Steep” refers to its spectral slope, indicating that at higher radio frequencies the “source” (or object) very quickly grows fainter. “Ring” refers to the shape. And the “Non-Thermal Radiation” refers to the type of radiation, suggesting that there must be particles accelerating in powerful magnetic fields. SAURON is at least 1.2 million light years across, about 20 times the size of the Milky Way.</p>
<p>But SAURON doesn’t tick all the right boxes for us to say that it’s definitely an Odd Radio Circle. We detected a host galaxy but can find no evidence of radio emissions with the wavelengths and frequency that match those of host galaxies of the other known ORCs. </p>
<p>And even though SAURON has a number of features in common with Odd Radio Circle1 – the first Odd Radio Circle spotted – it differs in others. Its strange shape and its oddly behaving magnetic fields don’t align well with the main structure.</p>
<p>One of the most exciting possibilities is that SAURON is a remnant of the explosive merger of two supermassive black holes. These are incredibly dense objects at the centre of galaxies such as our Milky Way that could cause a massive explosion when galaxies collide. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-were-probing-the-secrets-of-a-giant-black-hole-at-our-galaxys-centre-108181">How we're probing the secrets of a giant black hole at our galaxy's centre</a>
</strong>
</em>
</p>
<hr>
<h2>More to come</h2>
<p>More investigation is required to unravel the mystery. Meanwhile, machine learning is quickly becoming an indispensable tool to find more strange objects by sorting through enormous datasets from telescopes. With this tool, we can expect to unveil more of what the universe is hiding.</p><img src="https://counter.theconversation.com/content/199688/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michelle Lochner receives funding from the National Research Foundation and the Department of Science and Innovation. </span></em></p>
Machine learning is becoming an indispensable tool in astronomy by sorting through enormous datasets from telescopes.
Michelle Lochner, Staff Scientist at the South African Radio Astronomy Observatory and Senior Lecturer in Astronomy, University of the Western Cape
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/198694
2023-02-01T12:08:35Z
2023-02-01T12:08:35Z
Seti: alien hunters get a boost as AI helps identify promising signals from space
<figure><img src="https://images.theconversation.com/files/507097/original/file-20230130-12-qfen8v.jpg?ixlib=rb-1.1.0&rect=672%2C272%2C2956%2C1999&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The new study analysed data gathered at the Green Bank Observatory in West Virginia.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/green-bank-west-virginia-october-15-762059119">Shutterstock</a></span></figcaption></figure><p>An international team of researchers looking for signs of intelligent life in space have used artificial intelligence (AI) to reveal eight promising radio signals in data collected at a US observatory.</p>
<p>The results of their research, <a href="https://www.nature.com/articles/s41550-022-01872-z">published in Nature Astronomy</a> are remarkable. The team hasn’t yet carried out an exhaustive analysis, but the paper suggests the signals have many of the characteristics we would expect if they were artificially generated. In other words, they are the kinds of signals we might pick up from an extraterrestrial civilisation broadcasting into space.</p>
<p>A cursory review of the new paper suggest these are indeed promising signals. They’re much more compelling than what is perhaps the most famous Seti candidate, <a href="https://astronomy.com/news/2020/09/the-wow-signal-an-alien-missed-connectio">the “Wow!” signal</a>, radio emission bearing the hallmarks of an extraterrestrial origin that was collected by an Ohio telescope in 1977.</p>
<p>Realistically, it’s most likely that these eight new signals were generated by human technology. But the real story here is the effectiveness of AI and <a href="https://en.wikipedia.org/wiki/Deep_learning">the techniques used by the team to</a> dig out rare and interesting signals previously buried in the noise of human-generated <a href="https://public.nrao.edu/telescopes/radio-frequency-interference/">radio frequency interference,</a> such as mobile phones and GPS.</p>
<p>Astronomers working in the field of <a href="https://www.seti.org/primer-seti-seti-institute">Seti (the search for extraterrestrial intelligence)</a> must filter out interference produced by radio communications here on Earth.</p>
<p>In this case, Peter Ma from the University of Toronto and his colleagues unleashed a set of algorithms on a mountain of data collected by the <a href="https://greenbankobservatory.org">Green Bank Telescope in West Virginia</a>, US. The data was gathered through a Seti initiative called <a href="https://seti.berkeley.edu/listen/">Breakthrough Listen</a>, established in 2015 by the investor Yuri Milner and his wife Julia. </p>
<p>Here are the characteristics astronomers look for in signals that could be artificially-generated: firstly they are <a href="https://en.wikipedia.org/wiki/Narrowband">narrow-band</a>, which means that where the radio transmission is confined to only a few frequency channels. They also disappear as the telescope is moved to another direction in the sky, and they exhibit <a href="https://en.wikipedia.org/wiki/Doppler_effect">“Doppler drifting”</a>, where the frequency of the signal changes in a predictable way with time. We would expect Doppler drifting because both the transmitter — on a distant planet, for example — and the receiver, on Earth, are moving.</p>
<figure class="align-center ">
<img alt="Artist's impression of exoplanets" src="https://images.theconversation.com/files/507060/original/file-20230130-22-kadncw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/507060/original/file-20230130-22-kadncw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507060/original/file-20230130-22-kadncw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507060/original/file-20230130-22-kadncw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507060/original/file-20230130-22-kadncw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507060/original/file-20230130-22-kadncw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507060/original/file-20230130-22-kadncw.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">Any artificial signals from deep space need to be distinguished from radio interference here on Earth.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/planets-deep-space-cosmos-nebula-stars-2057080619">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Buried in the noise</h2>
<p>The Breakthrough Listen project’s <a href="https://seti.berkeley.edu/blc1/">first candidate signal</a>, called BLC1, was first announced in 2020. But it was <a href="https://www.nature.com/articles/s41550-021-01508-8">later traced</a> to transmissions associated with cheap electronic devices on this planet. The application of AI techniques to the Breakthrough Listen observing programme, however, is a potential game changer for the field. Even seasoned Seti researchers are beginning to think that we might be on the cusp of a momentous scientific breakthrough.</p>
<p>This may explain renewed interest by groups around the world that are planning for Seti success. For example, a <a href="https://seti.wp.st-andrews.ac.uk">Seti post-detection hub</a> has been set up at the University of St Andrews in Scotland. This will study how humans should react if we discover we are not alone in the Universe.</p>
<p>The International Academy of Astronautics (IAA) <a href="https://iaaseti.org/en/">Seti permanent committee</a> oversees the <a href="https://iaaseti.org/en/protocols/">Seti post-detection protocols</a>, which outline what steps scientists should take in the event of detecting a genuine signal. The IAA has opted to update the text of the protocols sometime later this year.</p>
<p>But the new study highlights a problem with previous signals of interest. When the team took another look at the stars associated with the eight narrow-band transmissions, they could no longer detect the signals. </p>
<p>It would not be surprising if many, and perhaps the vast majority of bona-fide Seti signals, were isolated events. After all, what are the chances that we point our telescopes in exactly the right direction, at the right time and with the right frequency on multiple occasions?</p>
<h2>Missing ingredients</h2>
<p>As I <a href="https://theconversation.com/seti-new-signal-excites-alien-hunters-heres-how-we-could-find-out-if-its-real-152498">argued here</a> a few years ago, Seti surveys would greatly benefit from employing multiple radio telescopes, operating in a manner that’s known as a <a href="https://public.nrao.edu/ask/how-does-a-radio-interferometer-work/">classical interferometer network</a>. </p>
<p>These telescope arrays (groups of several antennas observing together) generate huge amounts of data. With AI onboard, the challenge is perhaps more manageable than previously thought. </p>
<p>Breakthrough Listen is already using telescope arrays such as <a href="https://www.sarao.ac.za/science/meerkat/about-meerkat/">MeerKAT in South Africa</a> for Seti searches. In Europe, researchers have been experimenting with <a href="https://www.evlbi.org">arrays that span the globe</a>.</p>
<p>This European approach would help us isolate signals from human-made interference, give us multiple independent detections of individual events, and permit us to localise signals to individual stars and possibly orbiting planets. </p>
<p>Among the future projects is the <a href="https://www.skao.int/en">Square Kilometre Array</a>, an international project to build the two largest telescope arrays in the world, which will be based in Australia and South Africa. Another upcoming project is the <a href="https://ngvla.nrao.edu">next generation VLA (ngVLA)</a>, a series of linked telescope facilities that will be spread across the United States. These radio telescope arrays will be even more sensitive than current instruments.</p>
<p>It’s my belief — and indeed hope — that somewhere out there intelligent beings are waiting to be discovered. The AI revolution might be the missing ingredient that previous endeavours have lacked. In particular, AI algorithms will eventually evolve into powerful tools that no longer suffer from <a href="https://www.nist.gov/news-events/news/2022/03/theres-more-ai-bias-biased-data-nist-report-highlights">human biases</a>. </p>
<p>Lord Martin Rees, chairman of the Breakthrough Listen advisory board and the astronomer royal, has proposed that if we do find aliens they are likely to be <a href="https://theconversation.com/seti-why-extraterrestrial-intelligence-is-more-likely-to-be-artificial-than-biological-169966">intelligent machines</a> operating in the depths of space, unconstrained by the biological limitations placed on humans. </p>
<p>If we ever do find a bona-fide signal, it could just be that it’s mediated by machines on Earth and in space.</p><img src="https://counter.theconversation.com/content/198694/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Garrett is on the advisory board of the Breakthrough Listen initiative and the Seti Institute.</span></em></p>
Can artificial intelligence transform the search for alien intelligence?
Michael Garrett, Sir Bernard Lovell chair of Astrophysics and Director of Jodrell Bank Centre for Astrophysics, University of Manchester
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/195818
2022-12-05T01:24:09Z
2022-12-05T01:24:09Z
In Australia and South Africa, construction has started on the biggest radio observatory in Earth’s history
<figure><img src="https://images.theconversation.com/files/498810/original/file-20221204-24-mig410.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2326%2C1305&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's impression of some of the SKA-Low antenna stations.</span> <span class="attribution"><span class="source">DISR</span></span></figcaption></figure><p>Construction of the world’s biggest radio astronomy facility, the SKA Observatory, begins today. The observatory is a global project 30 years in the making.</p>
<p>With two huge two telescopes, one in Australia and the other in South Africa, the project will see further into the history of the Universe than ever before. </p>
<p>Astronomers like me will use the telescopes to trace hydrogen over cosmic time and make precise measurements of gravity in extreme environments. What’s more, we hope to uncover the existence of complex molecules in planet-forming clouds around distant stars, which could be the early signs of life elsewhere in the Universe.</p>
<p>I have been involved in the SKA and its precursor telescopes for the past ten years, and as the chief operations scientist of the Australian telescope since July. I am helping to build the team of scientists, engineers and technicians who will construct and operate the telescope, along with undertaking science to map primordial hydrogen in the infant universe.</p>
<h2>What is the SKA Observatory?</h2>
<p>The <a href="https://www.skao.int">SKA Observatory</a> is an intergovernmental organisation with dozens of countries involved. The observatory is much more than the two physical telescopes, with headquarters in the UK and collaborators around the world harnessing advanced computers and software to tailor the telescope signals to the precise science being undertaken. </p>
<p>The telescope in South Africa (called SKA-Mid) will use 197 radio dishes to observe middle-frequency radio waves from 350 MHz to more than 15 GHz. It will study the extreme environments of neutron stars, organic molecules around newly forming planets, and the structure of the Universe on the largest scales.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/aspiration-vs-delivery-the-long-road-to-the-square-kilometre-array-11221">Aspiration vs delivery: the long road to the Square Kilometre Array</a>
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<p>The Australian telescope (SKA-Low), in Western Australia, will observe lower frequencies with 512 stations of radio antennas spread out over a 74-kilometre span of outback.</p>
<p>The site is located within <a href="https://research.csiro.au/mro/inyarrimanha-ilgari-bundara/">Inyarrimanha Ilgari Bundara</a>, the CSIRO Murchison Radio-astronomy Observatory. This name, which means “sharing sky and stars”, was given to the observatory by the Wajarri Yamaji, the traditional owners and native title holders of the observatory site. </p>
<h2>Tuning in to the Universe</h2>
<p>After decades of planning, developing precursor telescopes and testing, today we are holding a ceremony to mark the start of on-site construction. We expect both telescopes will be fully operational late this decade.</p>
<p>Each of the 512 stations of SKA-Low is made up of 256 wide-band dipole antennas, spread over a diameter of 35 metres. The signals from these Christmas-tree-shaped antennas in each station are electronically combined to point to different parts of the sky, forming a single view. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/498829/original/file-20221205-17-8vv48o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/498829/original/file-20221205-17-8vv48o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498829/original/file-20221205-17-8vv48o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498829/original/file-20221205-17-8vv48o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498829/original/file-20221205-17-8vv48o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498829/original/file-20221205-17-8vv48o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498829/original/file-20221205-17-8vv48o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498829/original/file-20221205-17-8vv48o.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">An artist’s impression of a station of radio antennas. Each station has 256 antennas,
and the SKA-Low telescope will have 512 stations.</span>
<span class="attribution"><span class="source">DISR</span></span>
</figcaption>
</figure>
<p>These antennas are designed to tune in to low radio frequencies of 50 to 350 MHz. At these frequencies, the radio waves are very long – comparable to the height of a person – which means more familiar-looking dishes are an inefficient way to catch them. Instead the dipole antennas operate much like TV antennas, with the radio waves from the Universe exciting electrons within their metal arms.</p>
<p>Collectively, the 131,072 dipoles in the completed array will provide the deepest and widest view of the Universe to date. </p>
<h2>Peering into the cosmic dawn</h2>
<p>They will allow us to see out and back to the very beginning of the Universe, when the first stars and galaxies formed. </p>
<p>This key period, more than 13 billion years in our past, is termed the “cosmic dawn”: when stars and galaxies began to form, lighting up the cosmos for the first time. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/after-our-universes-cosmic-dawn-what-happened-to-all-its-original-hydrogen-65527">After our universe's cosmic dawn, what happened to all its original hydrogen?</a>
</strong>
</em>
</p>
<hr>
<p>The cosmic dawn marks the end of the cosmic dark ages, a period after the Big Bang when the Universe had cooled down through expansion. All that remained was the ubiquitous background glow of the early Universe light, and a cosmos filled with dark matter and neutral atoms of hydrogen and helium. </p>
<p>The light from the first stars transformed the Universe, tearing apart the electrons and protons in neutral hydrogen atoms. The Universe went from dark and neutral to bright and ionised. </p>
<p>The SKA Observatory will map this fog of neutral hydrogen at low radio frequencies, which will allow scientists to explore the births and deaths of the earliest stars and galaxies. Exploration of this key period is the final missing piece in our understanding of the life story of the Universe.</p>
<h2>Unimagined mysteries</h2>
<p>Closer to home, the low-frequency telescope will time the revolutions of pulsars. These rapidly spinning neutron stars, which fire out sweeping beams of radiation like lighthouses, are the Universe’s ultra-precise clocks.</p>
<p>Changes to the ticking of these clocks can indicate the passage of gravitational waves through the Universe, allowing us to map these deformations of spacetime with radio waves. </p>
<p>It will also help us to understand the Sun, our own star, and the space environment that we on Earth live within.</p>
<p>These are the things we expect to find with the SKA Observatory. But the unexpected discoveries will most likely be the most exciting. With an observatory of this size and power, we are bound to uncover as-yet-unimagined mysteries of the Universe.</p><img src="https://counter.theconversation.com/content/195818/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cathryn Trott receives funding from the Australian Research Council, and is employed by SKAO and Curtin University.</span></em></p>
Hundreds of thousands of antennas across the Western Australian outback will transform our view of the Universe.
Cathryn Trott, Research Fellow in Radio Astronomy, SKA-Low Chief Operations Scientist, Curtin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/183248
2022-05-19T13:08:31Z
2022-05-19T13:08:31Z
How 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 Observatory
Jacinta Delhaize, Lecturer, University of Cape Town
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/180595
2022-04-11T13:47:27Z
2022-04-11T13:47:27Z
Combined power of two telescopes is helping crack the mystery of eerie rings in the sky
<figure><img src="https://images.theconversation.com/files/457362/original/file-20220411-19-s6ezs4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some of the MeerKAT's 64 dishes, which astronomers use to collect huge amounts of data.</span> <span class="attribution"><span class="source">© South African Radio Astronomy Observatory (SARAO) </span></span></figcaption></figure><p>When astronomers dream of their ideal telescopes, it’s not that different to what people want from their TVs and computer monitors. Images they produce should be large and high definition, such as those from the Australian Square Kilometre Array Pathfinder (<a href="https://theconversation.com/the-australian-square-kilometre-array-pathfinder-finally-hits-the-big-data-highway-71217">ASKAP</a>), which have ~10k resolution (beyond the typical quality you get from digital TVs and digital cinematography). And they should have a high dynamic range, indicating high quality imaging with deep sensitivity to faint objects.</p>
<p>But not every telescope can do it all. That’s why complementary science – using some telescopes for some tasks, others for different but related tasks, and then combining the data – is so important in astronomy.</p>
<p>The value of complementary science is emphasised in <a href="https://arxiv.org/abs/2203.10669">our recent paper</a>. We worked with ASKAP and South Africa’s <a href="https://theconversation.com/africas-meerkat-first-light-images-have-blown-all-expectations-65246">MeerKAT telescope</a> to harness their different capabilities. In 2019, ASKAP discovered a rare and mysterious type of object, referred to as an “<a href="https://theconversation.com/wtf-newly-discovered-ghostly-circles-in-the-sky-cant-be-explained-by-current-theories-and-astronomers-are-excited-142812">odd radio circle</a>” (ORC). We didn’t know what these eerie glowing rings in the sky were. </p>
<p>It took data from MeerKAT to help us conclude that the circles are most likely enormous shells of gas, about a million light years across, emanating from the central galaxy.</p>
<figure class="align-center ">
<img alt="Graphic of the first odd radio circle discovered (ORC1) in a 2019 image from the Australian SKA Pathfinder (left), and the new detailed image from MeerKAT (right)." src="https://images.theconversation.com/files/456885/original/file-20220407-17-shyunu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/456885/original/file-20220407-17-shyunu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=248&fit=crop&dpr=1 600w, https://images.theconversation.com/files/456885/original/file-20220407-17-shyunu.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=248&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/456885/original/file-20220407-17-shyunu.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=248&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/456885/original/file-20220407-17-shyunu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=312&fit=crop&dpr=1 754w, https://images.theconversation.com/files/456885/original/file-20220407-17-shyunu.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=312&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/456885/original/file-20220407-17-shyunu.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=312&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The first odd radio circle discovered (ORC1) in a 2019 image from the Australian SKA Pathfinder (left), and the new detailed image from MeerKAT (right).</span>
<span class="attribution"><span class="source">Author supplied</span></span>
</figcaption>
</figure>
<p>Neither the discovery nor the detail would have been possible without both telescopes. ASKAP’s uniquely large field of view enables the discovery of rare objects like ORCs. It also enabled the discovery of many new Fast Radio Bursts; <a href="https://theconversation.com/how-scientists-are-working-together-to-solve-one-of-the-universes-mysteries-106556">these are</a> seemingly rare, extremely bright and short-lived flashes of radio waves.</p>
<p>Meanwhile, MeerKAT’s unique sensitivity and sampling ability, achieved by its large number of dishes (64, located in a remote part of South Africa’s Northern Cape province), highly sensitive low noise amplifiers and large bandwidth, enables these objects to be studied in greater detail. MeerKAT is the best imaging radio telescope of its kind.</p>
<p>Both ASKAP and MeerKAT are precursors to the <a href="https://www.skatelescope.org/">Square Kilometre Array (SKA)</a>. This is a global project to build the world’s largest and most sensitive radio telescope within the coming decade, co-located in South Africa and Australia. As our new research makes clear, complementary science will be at the heart of the SKA. This is an exciting prospect for African science, with South Africans putting themselves forward as world leaders within radio astronomy. </p>
<h2>The nature of ORC1</h2>
<p>Our new paper focuses on the first ORC that ASKAP discovered in 2019. We call it ORC1. MeerKAT provided something critical to deepening our understanding of what it might be and how it formed: beautiful, detailed images.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/456060/original/file-20220404-13-vx4fdo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/456060/original/file-20220404-13-vx4fdo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=593&fit=crop&dpr=1 600w, https://images.theconversation.com/files/456060/original/file-20220404-13-vx4fdo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=593&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/456060/original/file-20220404-13-vx4fdo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=593&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/456060/original/file-20220404-13-vx4fdo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=746&fit=crop&dpr=1 754w, https://images.theconversation.com/files/456060/original/file-20220404-13-vx4fdo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=746&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/456060/original/file-20220404-13-vx4fdo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=746&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">ORC1 was rendered in more detail by the MeerKAT telescope.</span>
<span class="attribution"><span class="source">Jayanne English using data from MeerKAT and the Dark Energy Survey</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/odd-radio-circles-that-baffled-astronomers-are-likely-explosions-from-distant-galaxies-178290">'Odd radio circles' that baffled astronomers are likely explosions from distant galaxies</a>
</strong>
</em>
</p>
<hr>
<p>The data we collected from MeerKAT was run through a <a href="https://www.ursi.org/proceedings/procGA21/papers/URSIGASS2021-Mo-J11-AM2-3.pdf">complex workflow</a>. This was developed and provided by the <a href="https://www.idia.ac.za">Inter-University Institute for Data Intensive Astronomy (IDIA)</a>, a partnership of three South African universities. This specialised software enabled specific data products to be generated, such as images of ORC1’s polarisation and “radio colour”.</p>
<p>MeerKAT’s technology revealed three especially important and previously uncertain details about ORC1. First was the object’s internal structure, revealed for the first time due to MeerKAT’s deep sensitivity and high resolution. We can now see ORC1 contains multiple arcs, a radio source where the central galaxy is located, and knots of radio emission associated with other galaxies within the vicinity. </p>
<p>Our theory is that the central galaxy, a few billion light years away, caused the ORC during a particular event. This may have been the merging of supermassive black holes or a starburst event (the rapid forming of many stars within the galaxy) that occurred billions of years ago. It was during this event, we hypothesise, that the ORC expanded to its enormous size of about 1.6 million light years. </p>
<p>The second detail revealed by MeerKAT’s data relates to the ORC’s polarisation, made possible by its deep sensitivity.</p>
<p>All light from the electromagnetic spectrum is polarised: its magnetic and electric fields are oriented in a certain direction. However, <a href="https://www.britannica.com/science/wave-particle-duality">waves or photons</a> from an unpolarised source of light are randomly polarised – they do not tend toward any particular orientation. </p>
<p>Certain physical processes, such as the presence of magnetic fields, can polarise light. This causes some or all of the waves to be oriented in the same direction. We found that ORC1 is strongly polarised along its outer ring.</p>
<p>The third detail was the structure of ORC1’s spectral index or “radio colour”: how its brightness changes across frequency. </p>
<p>Typically, spectral index is measured with several radio telescopes combined, each observing at a different frequency that one can compare to see how the brightness changes. For large resolved sources like ORC1, there’s huge scope for uncertainty. MeerKAT’s large bandwidth enabled us to measure an “in-band” spectral index map across the entire source. Within this map, every pixel itself measures the spectral index across the many frequencies we’ve combined. Our resulting map showed a steep spectral index across both the ring and its internal structure, suggesting they may have been produced by the same mechanism.</p>
<p>These new details fit with an explanation where synchrotron radiation (electrons whizzing around magnetic fields) is causing the radio emission, from a shell of gas in the form of a spherical shock wave. However, the internal arcs and rings require further explanation. We hypothesised that these are caused by the nearby galaxies moving through the shell and leaving trails in their wake.</p>
<h2>New questions to pursue</h2>
<p>So, what does it all mean? As with so much radio astronomy, we’re not certain: more data and information added to the mystery, with some clues provided.</p>
<p>However, we have three hypotheses to explain the nature of ORCs. One: it’s a spherical shell from an expanding shock wave caused by a huge explosion, such as the coalescing of two supermassive black holes. Two: it’s a spherical shell from the “termination shock” of a previous “starburst” event – when many stars rapidly formed within the galaxy over a short period of time. Three: it may be a view from one end of powerful radio jets of highly energetic particles that spew out from near a central supermassive black hole.</p>
<p>Not having definite answers may strike some as frustrating. But this is the nature of some science. What’s exciting is that there’s more to come: the SKA, which is due to become operational within the coming decade, will probe even more deeply into faint, rare and mysterious objects. This almost guarantees the discovery of the unexpected, as we’ve seen throughout the history of science, and as we now see with ORCs. Future discoveries far above us may look faint – but the possibilities paint a bright future.</p><img src="https://counter.theconversation.com/content/180595/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jordan Collier works for the Inter-University Institute for Data-Intensive Astronomy. He is affiliated with Western Sydney University and CSIRO Astronomy and Space Science.</span></em></p>
Complementary science will be at the heart of the Square Kilometre Array.
Jordan Collier, ilifu Support Astronomer, Inter-University Institute for Data Intensive Astronomy
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/178290
2022-03-21T19:04:36Z
2022-03-21T19:04:36Z
‘Odd radio circles’ that baffled astronomers are likely explosions from distant galaxies
<figure><img src="https://images.theconversation.com/files/451777/original/file-20220314-22-5opbh8.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C2355%2C2145&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Jayanne English using data from MeerKAT and the Dark Energy Survey</span></span></figcaption></figure><p>In 2019, my colleagues and I discovered spooky glowing rings in the sky using <a href="https://theconversation.com/the-australian-square-kilometre-array-pathfinder-finally-hits-the-big-data-highway-71217">CSIRO’s ASKAP radio telescope</a> in Western Australia. The rings were unlike anything seen before, and we had no idea what they were.</p>
<p>We dubbed them odd radio circles, or ORCs. They continue to puzzle us, but new data from South Africa’s <a href="https://theconversation.com/africas-meerkat-first-light-images-have-blown-all-expectations-65246">MeerKAT</a> telescope are helping us solve the mystery.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/wtf-newly-discovered-ghostly-circles-in-the-sky-cant-be-explained-by-current-theories-and-astronomers-are-excited-142812">'WTF?': newly discovered ghostly circles in the sky can't be explained by current theories, and astronomers are excited</a>
</strong>
</em>
</p>
<hr>
<p>We can now see each ORC is centred on a galaxy too faint to be detected earlier. The circles are most likely enormous explosions of hot gas, about a million light years across, emanating from the central galaxy.</p>
<p><a href="https://arxiv.org/abs/2203.10669">Our paper showing these results</a> has been peer-reviewed and accepted for publication by Monthly Notices of the Royal Astronomical Society. </p>
<h2>A closer look</h2>
<p>We now have beautiful images of one of these rings taken with South Africa’s MeerKAT radio telescope, which shows the ORC in stunning detail. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/451776/original/file-20220314-19-wyzm9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/451776/original/file-20220314-19-wyzm9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451776/original/file-20220314-19-wyzm9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=542&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451776/original/file-20220314-19-wyzm9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=542&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451776/original/file-20220314-19-wyzm9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=542&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451776/original/file-20220314-19-wyzm9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=682&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451776/original/file-20220314-19-wyzm9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=682&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451776/original/file-20220314-19-wyzm9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=682&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 (green/grey) image of the odd radio circle ORC1 superimposed on an optical image from the Dark Energy Survey.</span>
<span class="attribution"><span class="source">Created by Jayanne English using data from MeerKAT and the Dark Energy Survey.</span></span>
</figcaption>
</figure>
<p>For example, MeerKAT sees a small blob of radio emission in the centre of the ring, which is coincident with a distant galaxy. We are now fairly certain this galaxy generated the ORC. </p>
<p>We see these central galaxies in other ORCs too, all at vast distances from Earth. We now think that these rings surround distant galaxies about a billion light years away, which means the rings are enormous – around a million light years across. </p>
<p>From modelling the faint cloudy radio emission that MeerKAT detects within the rings, it seems the rings are the edges of a spherical shell surrounding the galaxy, like a blast wave from a giant explosion in the galaxy. They look like rings instead of orbs only because the sphere appears brighter at the edges where there is more material along the line of sight, much like a soap
bubble. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5tYr_5sD-RA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Artist’s impression of odd radio circles exploding from a central galaxy. It is thought to take the rings 1 billion years to reach the size we see them today. The rings are so big (millions of light years across), they’ve expanded past other galaxies. <em>Sam Moorfield/CSIRO</em></span></figcaption>
</figure>
<h2>Energetic electrons</h2>
<p>MeerKAT has also mapped the <a href="https://en.wikipedia.org/wiki/Polarization_(waves)">polarisation</a> of the radio waves, which tells us about the magnetic field in the ring. Our polarisation image shows a magnetic field running along the edge of the sphere. </p>
<p>This suggests that an explosion in the central galaxy caused a hot blast to collide with the tenuous gas outside the galaxy. The resulting shock wave then energised electrons in the gas, making them spiral around the magnetic field, generating radio waves.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/449446/original/file-20220302-23-heybxq.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/449446/original/file-20220302-23-heybxq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449446/original/file-20220302-23-heybxq.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=508&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449446/original/file-20220302-23-heybxq.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=508&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449446/original/file-20220302-23-heybxq.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=508&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449446/original/file-20220302-23-heybxq.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=638&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449446/original/file-20220302-23-heybxq.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=638&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449446/original/file-20220302-23-heybxq.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=638&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Lines around the edge of the ORC show the direction of the magnetic field. A circular magnetic field like this indicates it has been compressed by a shock wave from the central galaxy.</span>
<span class="attribution"><span class="source">Created by Larry Rudnick from MeerKAT data.</span></span>
</figcaption>
</figure>
<p>One big surprise from the MeerKAT result is that within the ring we see several curved filaments of radio emission. We still don’t know what these are. </p>
<p>But we do know that the sphere is so huge that it has swallowed up other galaxies as it blasted out from the central galaxy. Perhaps the filaments are trails of gas ripped off the galaxies by the passing shock wave?</p>
<h2>Colliding black holes or the birth of millions of stars?</h2>
<p>The big question, of course, is what caused the explosion. We are exploring two possibilities. </p>
<p>One is that they were caused by the merging of two <a href="https://theconversation.com/speaking-with-meg-urry-on-supermassive-black-holes-48375">supermassive black holes</a>. Such a “merger event” releases an enormous amount of energy, enough to generate the ORC. </p>
<p>Another possibility is that the central galaxy went through a “<a href="https://theconversation.com/red-and-dead-future-for-a-galaxy-running-out-of-star-fuel-28912">starburst</a>” event, in which millions of stars were suddenly born from the gas in the galaxy. Such a starburst causes hot gas to blast out from the galaxy, causing a spherical shock wave. </p>
<p>Both black hole mergers and starburst events are rare, which accounts for why ORCs are so rare (only five have so far been reported).</p>
<p>The puzzle of ORCs is not solved yet, and we still have much to learn about these mysterious rings in the sky. So far, we have only detected them with radio telescopes – we see nothing from the rings at optical, infrared, or X-ray wavelengths. </p>
<h2>Getting a better view</h2>
<p>To find out more, we need a tool even more sensitive than MeerKAT and ASKAP. Fortunately, the global astronomical community is building just such an observatory – the <a href="https://www.skatelescope.org/">Square Kilometre Array</a> (SKA), an international effort with telescopes in South Africa and Australia. </p>
<p>ASKAP and MeerKAT were built to test the sites and technology for the SKA. Quite apart from their role as precursors for the SKA, both telescopes have been hugely successful in their own right, making major discoveries in their first years of operation. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/analysis-of-2-000-galaxies-using-the-meerkat-radio-telescope-reveals-fresh-insights-166353">Analysis of 2 000 galaxies using the MeerKat radio telescope reveals fresh insights</a>
</strong>
</em>
</p>
<hr>
<p>Their success in discovering and studying ORCs therefore bodes well for the SKA. </p>
<p>The two telescopes are also beautifully complementary – ASKAP is superb at surveying large areas of sky and finding new objects, while MeerKAT is unrivalled for zooming in on those objects and studying them with higher sensitivity and resolution. </p>
<p>The SKA promises to surpass both. No doubt the SKA will find many more ORCs, and will also be able to probe them to find out what they are telling us about the lifecycle of galaxies.</p><img src="https://counter.theconversation.com/content/178290/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ray Norris is affiliated with CSIRO.</span></em></p>
Next-generation radio telescopes unravel the mysteries of ghostly circles in the sky.
Ray Norris, Professor, School of Science, Western Sydney University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/167529
2021-09-29T20:08:53Z
2021-09-29T20:08:53Z
How making a film exploring Indigenous stories of the night sky enriched my perspective as a scientist
<figure><img src="https://images.theconversation.com/files/422825/original/file-20210923-1932-1vieqxv.jpg?ixlib=rb-1.1.0&rect=39%2C13%2C2864%2C1794&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ilgari Inyayimaha (Shared Sky), painted by artists Margaret Whitehurst, Jenny Green, Barbara Merritt, Charmaine Green, Kevin Merritt, Sherryl Green, Tracey Green, Wendy Jackamarra, Susan Merry, Johnaya Jones, Gemma Merritt, Craig 'Chook' Pickett, and Nerolie Blurton. </span> <span class="attribution"><span class="source">Yamaji Art.</span></span></figcaption></figure><p>Have you ever looked up at the night sky and wondered what it all means? You are not alone. Billions of people before you have done the same. Looking at the stars to make sense of the universe, and our lives on Earth, extends back many tens of thousands of years, across all cultures.</p>
<p>A new 360 degree immersive film, Star Dreaming, set to screen around Australia and internationally, draws on our common wonder about the universe, exploring ancient culture and astrophysics, side by side.</p>
<p>In Australia, the world’s longest continuous culture can also claim to provide some of the <a href="https://www.bbcearth.com/news/australias-first-astronomers">first astronomers</a>. Indigenous Australians attach rich meaning to the night sky, and its connection to the land and our environment.</p>
<p>Also in Australia, much more recently, astrophysics has become one of the nation’s most successful and prominent sciences. In Western Australia, one of the world’s largest astronomy projects is being hosted, the <a href="https://www.skatelescope.org">Square Kilometre Array (SKA)</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Yy9xu_fTYyw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Watch the Star Dreaming trailer.</span></figcaption>
</figure>
<p>On the land of the <a href="https://www.wajarri.com.au/">Wajarri Yamaji people</a>, in mid-west WA, the SKA will be the largest radio telescope ever built, detecting radio waves from galaxies forming soon after the <a href="https://en.wikipedia.org/wiki/Big_Bang">Big Bang</a>, 13.8 billion years ago. This massive project will be completed towards the end of this decade.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/aspiration-vs-delivery-the-long-road-to-the-square-kilometre-array-11221">Aspiration vs delivery: the long road to the Square Kilometre Array</a>
</strong>
</em>
</p>
<hr>
<p>Over the last 13 years, I have been privileged to work with colleagues from <a href="http://www.yamajiart.com/">Yamaji Art</a> in <a href="https://www.cgg.wa.gov.au/">Geraldton</a>, exploring Indigenous stories about the sky alongside the stories of the <a href="https://www.talesofthenightsky.com/">Greeks and Romans</a>, and the astrophysical stories about the universe. We have learned from each other and taken our experience to the world through <a href="https://theconversation.com/indigenous-culture-and-astrophysics-a-path-to-reconciliation-42607">art exhibitions</a>.</p>
<p>Three years ago, we started work on Star Dreaming. It has been filmed using a <a href="https://en.wikipedia.org/wiki/Fulldome">360 degree camera</a> and is designed to be shown inside a dome, like a planetarium. Star Dreaming is an immersive experience, combining live action and CGI animation, and a unique cross-cultural exploration. </p>
<p>The film is a narrative, following two children from Geraldton as they discover the astrophysical story of the universe and Yamaji stories of the sky and land. Max Winton and <a href="https://collection.aiatsis.gov.au/austlang/language/w12">Amangu</a> girl Lucia Richardson make their acting debuts, as do I as “the scientist”.</p>
<p>Filming was interesting and demanding. Over four days, we filmed prototype SKA antennas (from a drone), the landscape (including in scorching hot creek beds), and indoor sequences. The director, <a href="https://www.imdb.com/name/nm3974304/">Perun Bonser</a> (an <a href="https://www.ngarluma.com.au/">Ngarluma</a> man), <a href="https://www.imdb.com/name/nm0715196/">Julia Redwood</a> (producer), and cast and crew had their work cut out.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/420062/original/file-20210908-17-1jf53if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/420062/original/file-20210908-17-1jf53if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/420062/original/file-20210908-17-1jf53if.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/420062/original/file-20210908-17-1jf53if.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/420062/original/file-20210908-17-1jf53if.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/420062/original/file-20210908-17-1jf53if.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/420062/original/file-20210908-17-1jf53if.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">Left to right: director, Perun Bonser, Steven Tingay, Max Winton, Lucia Richardson, and producer, Julia Redwood setting up a shot to explain the expansion of the universe using bread dough.</span>
<span class="attribution"><span class="source">Prospero Productions</span></span>
</figcaption>
</figure>
<p>The film starts with the Big Bang, the origin of all matter and energy, space and time. We look at the <a href="https://en.wikipedia.org/wiki/Stellar_evolution">life cycle of stars</a>, and how stars produced the atoms that make up the Earth — and us. Without stars, we would not exist. We explain the speed of light, the temperatures and colours of stars, and the basics of how the SKA works.</p>
<p>This is interwoven with Indigenous stories, like the astonishing Emu in the Sky, which appears after dusk in March/April toward the east, appearing to sit on its nest on the horizon. This is the same time of year when real emus lay their eggs and tend to them. </p>
<p>When the Emu in the Sky appears, Indigenous people know it is time to hunt for the eggs. As Yamaji artist Margaret Whitehurst says in the film, “good tucker!” Margaret and fellow Yamaji artist and poet Charmaine Green lead the kids on an egg hunt, and cook up the results.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/420064/original/file-20210908-27-2qw6ob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/420064/original/file-20210908-27-2qw6ob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=726&fit=crop&dpr=1 600w, https://images.theconversation.com/files/420064/original/file-20210908-27-2qw6ob.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=726&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/420064/original/file-20210908-27-2qw6ob.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=726&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/420064/original/file-20210908-27-2qw6ob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=913&fit=crop&dpr=1 754w, https://images.theconversation.com/files/420064/original/file-20210908-27-2qw6ob.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=913&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/420064/original/file-20210908-27-2qw6ob.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=913&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">After discovering that the appearance of the Emu in the Sky tells people when to hunt for Emu eggs, Max and Lucia go on the hunt with Charmaine Green (right) and Margaret Whitehurst.</span>
<span class="attribution"><span class="source">Prospero Productions</span></span>
</figcaption>
</figure>
<p>Yamaji artists Barbara and Kevin Merritt show the kids the Seven Sisters, the Indigenous story of a hunter pursuing seven sisters across the country and into the night sky — repeated every night. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/422826/original/file-20210923-17-1gcd3sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/422826/original/file-20210923-17-1gcd3sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/422826/original/file-20210923-17-1gcd3sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422826/original/file-20210923-17-1gcd3sa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422826/original/file-20210923-17-1gcd3sa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422826/original/file-20210923-17-1gcd3sa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422826/original/file-20210923-17-1gcd3sa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422826/original/file-20210923-17-1gcd3sa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The author with Max and Lucia.</span>
<span class="attribution"><span class="source">Prospero Productions</span></span>
</figcaption>
</figure>
<p>Turns out, this is almost identical to an ancient story of the Greeks and Romans for this group of stars, also identified as seven sisters (the Pleiades) being chased by a hunter (Orion).</p>
<p>How is that cultures on opposite sides of the Earth, separated by thousands of years, arrive at the same story for the same group of stars? These are mysteries that hint at common origins.</p>
<p>As a scientist, I’ve learned so much from being with the artists and sharing our stories together. I have a much richer perspective on the universe and Indigenous culture, well beyond the night sky, as a result of our time together. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/songlines-tracking-the-seven-sisters-is-a-must-visit-exhibition-for-all-australians-89293">Songlines: Tracking the Seven Sisters is a must-visit exhibition for all Australians</a>
</strong>
</em>
</p>
<hr>
<p>Another Yamaji artist, Wendy Jackamarra, paints the Jewel Box, a colourful cluster of stars right next to the Southern Cross that can only be seen with a telescopes; it comes to life on the screen, as does Margaret’s painting of the Emu in the Sky, and Barbara’s painting of the Seven Sisters. The paintings reveal themselves through CGI, telling their stories as the different elements come together. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/420067/original/file-20210908-22-k9eqmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/420067/original/file-20210908-22-k9eqmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/420067/original/file-20210908-22-k9eqmg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/420067/original/file-20210908-22-k9eqmg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/420067/original/file-20210908-22-k9eqmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/420067/original/file-20210908-22-k9eqmg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/420067/original/file-20210908-22-k9eqmg.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">Charmaine Green, with Max and Lucia, as Wendy Jackamarra (right) and Glenda Jackamarra (next to Wendy) talk about the Jewel Box star cluster and Wendy’s painting of it.</span>
<span class="attribution"><span class="source">Prospero Productions</span></span>
</figcaption>
</figure>
<p>I’ve been asked, “what do you want people to take away from the film?” Of course, I want people to come away with a better understanding of Indigenous culture, and to have learned something about the science. But, to me, the film captures intertwined cultural and scientific perspectives that are common to all peoples. </p>
<p>The atoms in our bodies are produced in stars and scattered into space when those stars die, providing the building blocks for planets and life. For many millennia, humans have sat under the night sky and watched all this unfold, our different cultural stories underpinned by our common sense of wonder.</p>
<p>Differences in race, religion, culture, politics, and society melt away with that perspective. We all experience a shared sky, a common origin. </p>
<p><em>Star Dreaming is screening at the <a href="https://visit.museum.wa.gov.au/maritime/under-dome-cinema-experience-presents-star-dreaming">WA Maritime Museum in Fremantle, WA</a>. Keep an eye out for it in major cities and planetaria across Australia before the end of 2021. In 2022 it will be screened around the world. All aspects of the film and the project, including its name, were derived from consultations and formal sign-off between the Indigenous participants, Prospero Productions, and the scientists.</em></p><img src="https://counter.theconversation.com/content/167529/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven Tingay receives funding from the Australian Government and the Government of Western Australia. He is a member of the Australian Labor Party.</span></em></p>
A new 3D film follows two children as they discover the astrophysical story of the universe and Yamaji stories of the sky and land. Making it was an extraordinary cross-cultural experience.
Steven Tingay, John Curtin Distinguished Professor (Radio Astronomy), Curtin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/166353
2021-08-23T15:10:45Z
2021-08-23T15:10:45Z
Analysis of 2 000 galaxies using the MeerKat radio telescope reveals fresh insights
<figure><img src="https://images.theconversation.com/files/416726/original/file-20210818-21-1ngevx2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">MeerKAT, the precursor to the massive Square Kilometre Array, allows astronomers to gather huge amounts of data about galaxies.</span> <span class="attribution"><span class="source">Photo by Jaco Marais/Foto24/Gallo Images/Getty Images</span></span></figcaption></figure><p>Galaxies – massive collections of gas, dust, and billions of stars and their solar systems – are a fundamental component of our Universe. Understanding how they have formed and evolved over cosmic eras remains one of the greatest challenges of modern astronomy. </p>
<p>There are a few reasons for this. First, the number of galaxies: astronomers <a href="https://singularityhub.com/2021/01/15/how-many-galaxies-are-in-the-universe-a-new-answer-emerges-from-the-darkest-sky-ever-observed/">have estimated</a> that there are roughly 200 billion galaxies in our Universe. Second, the sheer size and age of these galaxies. Their ages range from 100 million to 10 billion years and the size ranges from roughly 3,000 to 300,000 light years. One light year is 9.46 x 10¹² km – clearly, then, galaxies are huge and ancient.</p>
<p>However, galaxies aren’t totally mysterious. Technology is allowing astronomers to study and analyse them in far more detail than was previously possible. Our <a href="https://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/stab2290/6346552?redirectedFrom=fulltext">new study</a> used observations from the powerful MeerKAT radio telescope array, located in South Africa, to analyse more than 2,000 galaxies. MeerKAT is the most sensitive radio telescope in the southern hemisphere until the <a href="https://www.skatelescope.org/">Square Kilometre Array</a> (SKA, which will be the world’s largest radio telescope) is completed. </p>
<p>Our findings suggest that, within the galaxies we analysed, their course of evolution is likely accompanied by cosmic ray electrons losing energy with time. The energy does not – and cannot – simply vanish. Instead, as the electrons slow down, their energy is converted into that of the electromagnetic emissions. These emissions, after escaping the confines of the galaxy and traversing the cosmic distances, are among the telltale signals picked up by the MeerKAT.</p>
<p>These findings help us better understand the nature of these galaxies, and furthermore, the formation and evolution of galaxies in general – including our home galaxy, the Milky Way, which may be undergoing a similar process at the moment. This isn’t a process to worry about; it’s just something scientists want to understand better.</p>
<h2>Combining the data</h2>
<p>Our study was what’s called a statistical analysis. Different astrophysical phenomena create electromagnetic waves in different wavelengths, including radio, visible light, infrared, ultraviolet, and x-rays. It is therefore important to be able to combine different observations across a broad range of spectra. That’s what a statistical analysis allows.</p>
<p>We selected 2,094 galaxies that are active in forming stars, which means they are energetic and young – in cosmic time-scales. This is an ideal sample to study the way that galaxies grow up and the key features that affect their formation and evolution. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/416710/original/file-20210818-23-g3x5g8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/416710/original/file-20210818-23-g3x5g8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=530&fit=crop&dpr=1 600w, https://images.theconversation.com/files/416710/original/file-20210818-23-g3x5g8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=530&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/416710/original/file-20210818-23-g3x5g8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=530&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/416710/original/file-20210818-23-g3x5g8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=666&fit=crop&dpr=1 754w, https://images.theconversation.com/files/416710/original/file-20210818-23-g3x5g8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=666&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/416710/original/file-20210818-23-g3x5g8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=666&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Correlation between the mass of the galaxies (X-axis) and the difference of their radio emissions at different radio frequencies (Y-axis). Each symbol represents an individual galaxy. The image of an example galaxy is from NASA/ESA Hubble Space Telescope. T means the time for light to travel from these galaxies to us.</span>
<span class="attribution"><span class="source">Image created by Fangxia An (IDIA/UWC).</span></span>
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<p>The distances to these galaxies are so great that light, the fastest messenger in the Universe, takes roughly 1 to 11 billion years to arrive from them. So, the galaxies we observe now reflect how they used to be roughly 1 to 11 billion years ago; they are at different evolutionary stages. </p>
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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>
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<p>Next, we studied the fundamental physical properties of these distant galaxies by combining the new observations from MeerKAT and the existing observational data from other telescopes. The MeerKAT data were collected over nearly 20 hours as part of the MeerKAT International GHz Tiered Extragalactic Exploration (<a href="http://idia.ac.za/mightee/">MIGHTEE</a>) project. This seeks to observe the deep extragalactic space to explore the cosmic evolution of galaxies. It is one of the MeerKAT’s large survey projects prioritised by the <a href="https://www.sarao.ac.za/about/sarao/">South African Radio Astronomy Observatory</a>.</p>
<h2>Key findings</h2>
<p>By combining the emission of light in visible, infra-red, and radio from these selected 2,094 galaxies, the study measured how massive, how active, and how bright they appear to be at different radio frequencies, as well as some other fundamental physical properties. Then we connected the intensities of radio emission with the measured physical properties of these galaxies.</p>
<p>The difference between the radio emissions at different radio frequencies was correlated with the mass of the galaxies. On average, the most massive galaxies show the largest difference of radio emission intensity at different radio frequencies. On average, we find that the more massive a galaxy is, the larger such a difference tends to be. </p>
<p>Further quantitative analysis shows that this statistical trend is consistent with the radio emission from cosmic ray electrons that are gradually slowing down – a process that accompanies these galaxies throughout different stages of evolution.</p><img src="https://counter.theconversation.com/content/166353/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fangxia An is affiliated with Inter-University Institute for Data Intensive Astronomy, and Department of Physics and Astronomy, University of the Western Cape. </span></em></p>
Technology is allowing astronomers to study and analyse galaxies in far more detail than was previously possible.
Fangxia An, Postdoctoral researcher, Inter-University Institute for Data Intensive Astronomy
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/156586
2021-05-26T18:09:24Z
2021-05-26T18:09:24Z
COVID-19 budget pressures threaten curiosity-driven science. That’s a bad thing
<figure><img src="https://images.theconversation.com/files/401830/original/file-20210520-19-1xxbb8u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some of the dishes that make up the Square Kilometre Array's radio telescope system. This kind of "blue skies" research can have great real-world value. </span> <span class="attribution"><span class="source">MUJAHID SAFODIEN/AFP via Getty Images</span></span></figcaption></figure><p>Management of the COVID-19 pandemic has governments around the world walking a delicate tightrope between containing the spread of the virus and the interactions required to sustain daily living. <a href="https://www.worldbank.org/en/publication/global-economic-prospects">Economies</a> and <a href="https://www.imf.org/en/News/Articles/2020/08/03/na080320-south-africa-looks-toward-inclusive-recovery-to-stabilize-debt-boost-growth">national budgets</a> have been placed under tremendous pressure.</p>
<p>This means that budgets are being cut. And one area that’s affected is research. In South Africa, for instance, in 2020 the national science budget was <a href="https://www.researchprofessionalnews.com/rr-news-africa-south-2020-7-this-is-the-butcher-s-bill-for-south-africa-s-science-cuts/">reduced by 15%</a> – a direct result, the <a href="https://www.researchprofessionalnews.com/rr-news-africa-south-2020-7-this-is-the-butcher-s-bill-for-south-africa-s-science-cuts/">government confirmed</a>, of the pandemic’s effects. In May 2021 it <a href="https://researchprofessionalnews.com/rr-news-africa-south-2021-5-parliament-rallies-behind-south-africa-s-cash-strapped-science-department/">was increased</a>, but only by 1.4% – below inflation.</p>
<p>A shift in government spending is likely to continue in the coming months and years. So, where does this leave blue skies science? Will it also be a casualty of COVID-19?</p>
<p><a href="https://www.labmate-online.com/news/news-and-views/5/breaking-news/what-is-lsquoblue-sky-sciencersquo/30187">Blue skies science</a> is the kind of research that’s driven by curiosity. Its real world applications – or its relevance to society – aren’t always immediately apparent; it begins because scientists ask one simple question: “why?” For example, <a href="http://aappsbulletin.org/myboard/read.php?Board=apctp&id=111">wifi grew out of a technique</a> that was developed by radio astronomers in the late 1970s to analyse radio waves from black holes, and the <a href="https://www.aps.org/publications/apsnews/200705/physicshistory.cfm#:%7E:text=By%201920%2C%20physicists%20knew%20that,born%20in1891%20in%20Manchester%2C%20England.">discovery of the neutron in 1932</a> has led to new fields in applied science, including energy production and materials diagnostics.</p>
<p>The pandemic has underscored that the world requires agility for survival. That makes blue skies science – which encourages curiosity and nimble thinking – perhaps more important than ever. But this will require a long-term view from governments and funders, particularly by providing decades of funding and freedom to allow scientists to ask the “why?” questions. </p>
<p>I have been fortunate to spend almost two decades working in astronomy research, which is just about as “blue skies” as one can get. It was the support and vision of South Africa’s commitment to blue skies science, especially astronomy, that drew me and many other researchers back home from a position abroad. In my role at the <a href="http://www.astro4dev.org/">Office of Astronomy for Development</a>, I’ve seen firsthand how blue skies science acts as a gateway into science, technology and data science fields and how a combination of skills in applied and blue-skies science can contribute to pressing socio-economic questions.</p>
<p>Now budget pressures are intensifying. But, I would argue, unless there is increased support for researchers in exploratory fields and in forays into cross disciplinary projects, the expertise, momentum and benefits that have accumulated over the last decades will be lost. There may be short-term successes, but they will likely be at the expense of longer term, potentially bigger impact science.</p>
<p>Continued funding for both blue skies and applied science is necessary as boundaries between the two become more porous. This is important because it would mean that scientists could increasingly contribute to immediate societal impact, while following avenues out of pure curiosity. </p>
<h2>Scientific agility</h2>
<p>In the year since COVID-19 first emerged as global pandemic, my colleagues and I have watched scientific agility in action in South Africa on a number of fronts.</p>
<p>One example has been the role that the South African Radio Astronomy Observatory took to help lead the country’s <a href="https://www.dailymaverick.co.za/article/2020-07-07-from-telescopes-to-ventilators-how-the-countrys-engineers-and-designers-have-retooled-for-the-covid-19-crisis/">national ventilator project</a>. Ventilators are crucial for those with severe COVID-19, but there were limited numbers available worldwide. The national ventilator project aimed to manufacture simple non-invasive ventilators using locally available materials and processes. </p>
<p>The Office of Astronomy for Development, the African Planetarium Society and African Astronomical Society <a href="http://www.astro4dev.org/call-for-covid-19-related-proposals/">collectively redirected funding</a> to assuage the effects of the pandemic. With some organisational agility, the funding could be redirected to causes slightly outside the key mission of these organisations.</p>
<p>We’ve also seen scientific agility at an individual level. Statisticians and simulation scientists from numerous fields have <a href="https://www.nasa.gov/ames/covid-19">responded to the call</a> to work with epidemiologists in modelling the pandemic.</p>
<p>Similarly, many blue skies science projects, like the <a href="https://icecube.wisc.edu/">IceCube Neutrino Observatory</a> and the <a href="https://www.bsu.edu/news/press-center/archives/2020/4/planetarium-computers-used-to-battle-covid19">Charles W. Brown Planetarium</a>, have made computing power available to model the virus protein properties of SARS-CoV-2. </p>
<h2>In it for the long haul</h2>
<p>Building solid research capabilities is a long-term endeavour. It is often internationally funded and operated, and can last several decades. One example is the <a href="https://theconversation.com/how-the-ska-telescope-is-boosting-south-africas-knowledge-economy-96228">Square Kilometre Array (SKA)</a>. A multinational endeavour, it is <a href="https://www.peralex.com/radio-astronomy/">spurring</a> technological breakthroughs and industrial spin-offs.</p>
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Read more:
<a href="https://theconversation.com/a-big-moment-for-africa-why-the-meerkat-and-astronomy-matter-99714">A big moment for Africa: why the MeerKAT -- and astronomy -- matter</a>
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<p>Projects like this have significant momentum. Due to high sunk costs as well as cross-national mutual accountability, they’re unlikely to be halted, even if they are subjected to delays or de-scoping. </p>
<p>They are even likely to survive the immediate impact of budget cuts. These, however, have an immediate effect on a range of shorter term research projects. They also affect students and training. Most students and early career researchers are funded by “soft money”, allocated to a particular project over a short timescale, usually two or three years.</p>
<p>Having less soft money to go around means fewer graduate students to train, and fewer early career researchers to be employed. For those students who are funded, it may also mean reduced opportunities to receive training that will help them exploit the available research infrastructure. This funding pressure mounts up, and the impacts become visible over the medium term: reduced numbers of publications and projects are undertaken on these facilities, and there’s less opportunity to build and develop skills.</p>
<h2>What next?</h2>
<p>The value in blue skies science requires us to look beyond the obvious. It also requires us to consider timescales longer than the political. </p>
<p>The question is not so much about redirecting funding, but about designing a research environment that can accommodate integration of ideas across traditional research “silos”; an environment where there are avenues for experts to apply their skills outside their domains of expertise. As a collective, society would stand to gain so much more from blue skies research.</p><img src="https://counter.theconversation.com/content/156586/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vanessa McBride works for the Office of Astronomy for Development and the South African Astronomical Observatory. She receives funding from the National Research Foundation.</span></em></p>
The pandemic has underscored that the world requires agility for survival. That makes blue skies science, which encourages curiosity and nimble thinking, perhaps more important than ever.
Vanessa McBride, Astronomer, International Astronomical Union's Office of Astronomy for Development
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/160780
2021-05-13T02:55:40Z
2021-05-13T02:55:40Z
Money for telescopes and vaccines is great, but the budget’s lack of basic science funding risks leaving Australia behind
<p>The story of the past year has been the pandemic: from the first outbreaks in early 2020, the identification of the SARS-CoV-2 virus and methods to detect it, through to lockdown and quarantine measures, vaccine development, testing and finally distribution. The pandemic is not over, but the recovery has started. </p>
<p>At each stage, it has been scientists and researchers at the forefront of a rapid and successful national and global response to the pandemic. A nation’s capacity to respond to threats like a pandemic does not exist in a vacuum. It depends on scientists. You can’t research a solution without researchers. </p>
<p>In Australia, the higher education sector performs the vast bulk of research, including basic foundational research. This sector has been hit extremely hard by the pandemic, losing billions in revenue <a href="https://www.science.org.au/covid19/research-workforce">leading to the loss of research capacity</a> — the very capacity we need to continue to respond to the pandemic and recover. </p>
<p>For this reason, the lack of recognition for science and scientists in the <a href="https://theconversation.com/cuts-spending-debt-what-you-need-to-know-about-the-budget-at-a-glance-159226">federal budget</a>, and in particular for the foundational capacity in basic discovery science, is perplexing indeed. Such science capability underpins Australia’s resilience, not just against pandemics but also against natural disasters, economic shocks, technology disruption, the needs of an ageing population, and cyber warfare – many of the government’s stated priority areas. </p>
<p>There is some new funding in the budget, which is welcome. Initiatives such as support for the <a href="https://www.pm.gov.au/media/australia-invest-387-million-worlds-largest-radio-telescope">Square Kilometre Array radiotelescope</a>, supporting women in STEM, climate adaptation, clean energy and government digital resources are essential additions to the Australian scientific landscape. The proposed <a href="https://www.zdnet.com/article/budget-2021-a-patent-box-to-sprout-innovation-and-talent-attraction-measures/">patent box system</a> promises to stimulate investment in Australian science in medical technologies and clean energy. </p>
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Read more:
<a href="https://theconversation.com/cuts-spending-debt-what-you-need-to-know-about-the-budget-at-a-glance-159226">Cuts, spending, debt: what you need to know about the budget at a glance</a>
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<p>Much of this funding is for incremental, short-term, focused technology programs. But such mission-directed science, while worthy, does not substitute for discovery science. If the government wants these missions to be effective, it must invest in basic science too. </p>
<p>If universities are being asked to pivot away from over-reliance on international student income, and <a href="https://ministers.dese.gov.au/tudge/getting-more-australia-our-university-research">towards research commercialisation</a>, there must be a basic science pool to help fuel this translation of research findings into commercial outcomes. At the risk of mixing metaphors, the pivot will be ineffective without a pipeline.</p>
<p>More importantly, the budget does nothing to stem the loss of university science jobs. Failure to act on university funding before the start of the 2022 academic year will mean more university job losses – and it is clear from the decisions already taken at ANU (in science and medicine), <a href="https://www.theage.com.au/national/victoria/melbourne-uni-cuts-threaten-to-make-us-the-bogans-of-the-pacific-20210326-p57ehg.html">Melbourne</a>, Macquarie and Murdoch that these cuts will come from science research. </p>
<h2>Medical manufacturing capability</h2>
<p>While the government has not revealed in the budget how much money it has committed to onshore mRNA vaccine manufacturing, it is welcome news that there is commitment to developing this capability that will serve the nation well for decades. </p>
<p>The Australian Academy of Science is pleased the government has <a href="https://www.science.org.au/supporting-science/science-policy-and-analysis/submissions-government/2021-22-pre-budget-submission">heeded our advice</a> to future-proof Australia by developing this capability. It will allow Australia to build resilience against future pandemics and potential biosecurity threats that require us to have the onshore capacity to mass-produce vaccines. </p>
<p>Australia will require significant capability development alongside a manufacturing facility. A pipeline of knowledge will need to be developed, from fundamental to applied research related to mRNA vaccines and therapeutics. Australia will need a nationwide consortium of multidisciplinary expertise, in everything from data science to materials engineering, to become a world leader in this new technology.</p>
<p>Building our research capability in this area will allow us to continue solving existing challenges with mRNA vaccines. That’s why the science sector must be included in the scoping and investment in this new capability. </p>
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Read more:
<a href="https://theconversation.com/did-someone-drop-a-zero-australias-digital-economy-budget-spend-should-be-10-times-bigger-160626">Did someone drop a zero? Australia's digital economy budget spend should be 10 times bigger</a>
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<p>When I was appointed president of the Australian Academy of Science in 2018, I spoke about how it can take decades to translate the outcomes of basic research into something of real value for the community. This remains the case. It has always been the case. </p>
<p>Often, our political leaders want instant answers to the big questions. Australia’s science and research community delivered when it came to COVID-19, but it must be supported and funded to continue making fundamental discoveries if it is to deliver again. The future prosperity of our nation depends on it.</p><img src="https://counter.theconversation.com/content/160780/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Shine owns shares in CSL. He was previously Chairman of CSL.</span></em></p>
The federal budget contains money for big-ticket items like the SKA telescope and mRNA vaccines. But dwindling funds for universities and fundamental science will leave us vulnerable to future problems.
John Shine, President, Australian Academy of Science; Laboratory Head, Garvan Institute
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/152777
2021-01-12T15:07:36Z
2021-01-12T15:07:36Z
South African astronomy has a long, rich history of discovery – and a promising future
<figure><img src="https://images.theconversation.com/files/377956/original/file-20210111-23-12bfk2d.jpg?ixlib=rb-1.1.0&rect=4%2C492%2C2748%2C1655&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Southern African Large Telescope has been a key part of South Africa's astronomical contributions.</span> <span class="attribution"><span class="source">SAAO</span></span></figcaption></figure><p>The <a href="https://www.saao.ac.za/">South African Astronomical Observatory</a> in Cape Town is the oldest permanent observatory in the southern hemisphere: it turned 200 in 2020. </p>
<p>This observatory is a fundamental part of South Africa’s long history of astronomical research, which began when French academic <a href="https://academic.oup.com/astrogeo/article/43/2/2.25/281196">Nicolas-Louis de La Caille</a> visited Cape Town from 1751 to 1753. He undertook a careful examination of every square degree of the southern sky. This resulted in the first comprehensive sky survey ever made, in either hemisphere.</p>
<p>The Royal Observatory, Cape Town of Good Hope (today the South African Astronomical Observatory) was established in 1820. It became – and remained for 150 years – the most important source of star positions in the southern hemisphere sky. This was in terms of both accuracy and the number of measurements made. In the years that followed its foundation, the observatory’s laborious work led to important scientific discoveries. </p>
<p>Cape astronomers were responsible for, among other things, the first measurement of the distance to a star; the first photographic sky survey and the accurate measurement of the distance to the sun. They were at the forefront of developments in stellar spectroscopy. This is the detailed analysis of a star’s light to find out its composition and movement towards or away from the sun. They also determined the shape of the earth in the southern hemisphere and conducted the first accurate country-wide survey measurements of southern Africa. </p>
<h2>Measuring stellar distances</h2>
<p>In 1543 the mathematician and astronomer <a href="https://plato.stanford.edu/entries/copernicus/">Nicolaus Copernicus</a> asserted that the earth orbits the sun. This meant that people should be able to observe the apparent shift in the position of the nearest stars from different points in the earth’s orbit. But that had not been observed in the centuries that followed. The reason was, of course, that even the nearest stars are incredibly far away and the effect being looked for is very small. </p>
<p>When the Royal Observatory was founded in 1820, it was equipped with the most accurate star position measuring devices available. Eleven years later Thomas Henderson used those devices to make the first believable measurements of this effect, known as “<a href="https://www.space.com/30417-parallax.html">parallax</a>”. By observing the angular “movement” of Alpha Centauri – still the second-closest star known to us – and knowing also the size of the earth’s orbit, this gave the distance to the star by simple trigonometry. </p>
<p>A different technology, photography, would lead to more important astronomical discoveries at the Cape. All observatories in the 19th century made precise observations of star positions one by one and published catalogues of these. In 1882 the head of the Royal Observatory, David Gill, was surprised to receive a letter from a Mr Simpson, an amateur photographer in Aberdeen, a town elsewhere in the Cape. </p>
<p>Simpson had managed to photograph a bright comet that had just appeared. His photographic plates were sensitive enough to register stars in the background. This led to a “lightbulb” moment for Gill: he realised that the positions of stars could now be recorded in quantity on a permanent medium, more reliably than any visual observer could ever hope to do. </p>
<p>So he set up a special photographic telescope using the largest lens that he could find and set about making the first photographic star catalogue. This was called the <a href="http://adsabs.harvard.edu/full/1896AnCap...3....1G">Cape Photographic Durchmusterung</a> after its much more laboriously compiled northern hemisphere equivalent, put together in Bonn, Germany. </p>
<p>But it wasn’t just Cape Town that hosted an important astronomical site.</p>
<p>In 1903, the <a href="https://www.saasta.ac.za/johannesburg-observatory/">Johannesburg Observatory</a> was established. It achieved its greatest success in 1915 when its director, Robert Innes, discovered a very faint star near Alpha Centauri. </p>
<p>On various grounds he claimed it to be the nearest star to Earth; it took many years of investigation before this could be verified. The new discovery was named “Proxima Centauri”, meaning the nearest in the constellation Centaurus. Not only was it the nearest star but at that time of discovery it was the least luminous star ever discovered. Other dimmer stars have been found since, but Proxima still retains its nearest star status and its distance has been thoroughly verified from space satellites. </p>
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Read more:
<a href="https://theconversation.com/seti-new-signal-excites-alien-hunters-heres-how-we-could-find-out-if-its-real-152498">SETI: new signal excites alien hunters – here's how we could find out if it's real</a>
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<h2>Doubling the size of the Universe</h2>
<p>In 1948 the private Radcliffe Foundation in the United Kingdom set up in Pretoria what was for a time the largest telescope in the southern hemisphere and joint fourth largest in the world. This is a title currently held by the <a href="https://www.salt.ac.za/">Southern African Large Telescope</a>. </p>
<p>Early on in the Radcliffe’s existence the then director, David Thackeray, and his colleague Adriaan Wesselink discovered in our neighbouring galaxy, the Large Magellanic Cloud, a number of RR Lyrae variable stars that astronomers using smaller telescopes could not detect. These are stars that change their brightness in a well-defined manner over a cycle of a few days and whose average “wattage” is completely predictable.</p>
<p>By measuring the Magellanic Cloud stars’ average apparent brightnesses and comparing them to other RR Lyrae stars at known distances they determined that the cosmic distance scale originally published two decades before by Edwin Hubble and others was underestimated by about a factor of two. In effect, they doubled the size of the Universe. This result was announced to great acclaim at the triennial meeting of the <a href="http://adsabs.harvard.edu/full/1952JRASC..46..217D">International Astronomical Union in 1952</a>. </p>
<h2>More to come</h2>
<p>Today South African astronomy remains at the forefront of many initiatives and discoveries. It has become a leader in the field of radio astronomy with the MeerKAT telescope near Carnarvon and will within a decade be the host of an international project, the <a href="https://www.skatelescope.org/">Square Kilometre Array</a>.</p>
<p><em>This article is adapted from <a href="https://www.nrf.ac.za/sites/default/files/documents/04%20NRF%20SMM%20V3%20Issue3%20Highlights%20of%20Astronomy%20in%20South%20Africa%20Before%201972.pdf">a piece</a> that initially appeared in the South African National Research Foundation’s Science Matters Magazine.</em></p><img src="https://counter.theconversation.com/content/152777/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Glass 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>
Cape astronomers were responsible for, among other things, the first measurement of the distance to a star; the first photographic sky survey and the accurate measurement of the distance to the sun.
Ian Glass, Associate Research Astronomer, South African Astronomical Observatory
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/138421
2020-05-15T05:32:34Z
2020-05-15T05:32:34Z
Technology, international bonds, and inspiration: why astronomy matters in times of crisis
<figure><img src="https://images.theconversation.com/files/334213/original/file-20200512-66649-sgl6gh.jpg?ixlib=rb-1.1.0&rect=3282%2C0%2C4622%2C3922&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Alex Cherney / CSIRO</span></span></figcaption></figure><p>In an international emergency like the present one, you might expect the science of the stars to be the last thing on people’s minds. The problems facing both individuals and governments are infinitely more pressing than events in the depths of space. People are suffering unprecedented hardships. </p>
<p>Yet throughout history, astronomy has shown extraordinary resilience in times of crisis and has kept public support. Today, that resilience will be needed as a major international project, the <a href="https://www.skatelescope.org/">Square Kilometre Array</a> (SKA), is on the brink of construction. </p>
<p>The SKA will be the world’s largest radio telescope, and Australia will play a leading role in building and operating it. How can this benefit a nation focused on containing a global pandemic? </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-science-behind-the-square-kilometre-array-40870">The science behind the Square Kilometre Array</a>
</strong>
</em>
</p>
<hr>
<h2>Troubled times</h2>
<p>History shows the science of the stars is no stranger to crisis. Indeed, modern astronomy was born in a time of deep conflict, when the northern provinces of the Netherlands were engaged in difficult negotiations with Spain after 40 years of war. </p>
<p>In 1608, the fledgling telescope came out of obscurity in the hands of <a href="http://galileo.rice.edu/sci/lipperhey.html">Dutch spectacle-makers</a>, and its possibilities for astronomy were recognised. When news of this optical novelty reached Galileo Galilei in Padua the following May, he set about improving it – and the rest is history.</p>
<p>By the turn of the twentieth century, astronomical infrastructure had become big business, but two World Wars caused major disruptions. New telescope proposals were put on hold as manufacturers turned their hands to gunsights, rangefinders, binoculars and other “optical munitions”. </p>
<p>During the Second World War, one British company actually buried the 1.5-tonne mirror for a new <a href="http://articles.adsabs.harvard.edu/pdf/1989QJRAS..30...33G">South African telescope</a> in a field to avoid possible bomb damage. While delivery of the mirror was delayed until 1948, the telescope was a success, and is still at work today. </p>
<p>Similarly, in the United States, the 200-inch (5.1-metre) mirror for what was to be the world’s largest telescope at the time, at Mount Palomar, California, was cast in December 1934, but the instrument’s completion was <a href="https://www.astro.caltech.edu/palomar/about/history.html">delayed until 1949</a>. Although it is no longer the largest in the world, the Palomar telescope remains among the most effective. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/copernicus-revolution-and-galileos-vision-our-changing-view-of-the-universe-in-pictures-60103">Copernicus' revolution and Galileo's vision: our changing view of the universe in pictures</a>
</strong>
</em>
</p>
<hr>
<h2>Astronomy and COVID-19</h2>
<p>While hardly comparable to a world war, the present crisis constitutes an emergency of grave proportions, and it is important to put a project like the Square Kilometre Array (SKA) into perspective. </p>
<p>When completed, the telescope will provide radio astronomers with the largest and most advanced facility available to them. With an expected working lifetime of more than 50 years, it will explore the whole 13.8-billion year history of the Universe, yielding many exciting discoveries.</p>
<p>And spin-offs from the technologies under development have huge commercial potential, with tangible benefits for economic recovery. </p>
<p>One of the reasons governments fund research into the study of the Universe is that astronomy pushes technology to its limits – whether it be low-noise radio receivers, complex data management systems or sophisticated computer algorithms. Wifi, for example, <a href="https://csiropedia.csiro.au/wireless-lans/">had its origins</a> in Australian radio astronomy a quarter of a century ago. </p>
<p>More immediately, the construction of the SKA offers significant opportunities for local companies. The low-frequency component of the telescope will be built at the <a href="https://www.csiro.au/en/Research/Astronomy/ASKAP-and-the-Square-Kilometre-Array/MRO/About">Murchison Radioastronomy Observatory</a> in Western Australia’s remote Wajarri Yamatji country, one of the most radio-quiet places on Earth. </p>
<p>The project has so far spent $330 million in funding from the Australian and WA governments <a href="https://www.industry.gov.au/strategies-for-the-future/astronomy/co-hosting-the-square-kilometre-array">establishing the observatory</a> and building pathfinder instruments. </p>
<p>And on the wider horizon, “big science” facilities like the SKA require strong international partnerships, with collaboration among the project’s 14 member states representing a further positive outcome. Along with South Africa, where the <a href="https://southafrica.skatelescope.org/welcome/">mid-frequency component</a> of the telescope will be located, Australia can expect its scientific standing to be further enhanced as one of the SKA host nations.</p>
<h2>An inspiring science</h2>
<p>Although technological spin-offs are an important outcome of astronomical research, it is pure curiosity that is the ultimate driver. We are an inquisitive species, and the quest to know is what motivates researchers. </p>
<p>But it also inspires the rest of us with the staggering beauty of the universe and the appeal of scientific understanding. For youngsters in particular, that can prepare them for the jobs of the future, shaping an agile knowledge economy for our nation.</p>
<p>If the lessons of history are anything to go by, the SKA will be unlocking the secrets of the universe long after COVID-19 has subsided into memory. And that will be something of which we can all be proud.</p><img src="https://counter.theconversation.com/content/138421/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The Department of Industry, Science, Energy and Resources is one of the Australian government agencies responsible for the Square Kilometre Array. Fred Watson is also affiliated with Macquarie University, the University of New South Wales, the Queensland University of Technology, the University of Southern Queensland, the University of Sydney, and Western Sydney University.
</span></em></p>
When the outlook is dark, astronomy can help us take the long view and build for the future.
Fred Watson, Astronomer-at-Large, Department of Industry, Science, Energy and Resources, Australian Astronomical Observatory
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/110449
2019-02-12T12:53:21Z
2019-02-12T12:53:21Z
Data science is a growing field. Here’s how to train people to do it
<figure><img src="https://images.theconversation.com/files/256082/original/file-20190129-108370-1sqngs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Having data at your fingertips isn't enough - data scientists must know how to apply it.</span> <span class="attribution"><span class="source">Gorodenkoff/Shutterstock</span></span></figcaption></figure><p>The world is inundated with data. There’s a virtual tsunami of data moving around the globe, renewing itself daily. Take just the global financial markets. They generate <a href="https://www.globalfinancialdata.com/">vast amounts of data</a> – share prices, commodity prices, indices, option and futures prices, to name just a few.</p>
<p>But data is of no use if there aren’t people able to collect, collate, analyse and apply it to the benefit of society. All that data generated by global financial markets gets used for asset and wealth management – and it must be properly analysed and understood to inform good decision making. That’s where <a href="https://www.youtube.com/watch?v=X3paOmcrTjQ">data science</a> comes in.</p>
<p>Data science’s primary aim is to extract insight from data in various forms, both structured and unstructured. It’s a multi-disciplinary field, involving everything from applied mathematics to statistics and artificial intelligence to machine learning. And it’s growing. This is because of advances in computer technology and processing speed, the relatively low cost to store data, and the massive availability of data from the Internet and other sources such as global financial markets. </p>
<p>For data science to happen, of course, you need data scientists. Because data science is so wide in scope, being a data scientist covers a range of professions. These include statisticians, operations researchers, engineers, computer scientists, actuaries, physicists and machine learners. </p>
<p>This variety isn’t necessarily a bad thing. From my own practical experience, I quickly learnt that when solving data science problems, you need a range of people. Some can work in depth on theory and others can explore the application area. </p>
<p>But how should these data scientists be trained so they’re prepared for the big data challenges that lie ahead? </p>
<p>Data scientists typically use innovative mathematical techniques from their own subfields to try and solve problems in a particular application area. The application areas – finance, health, agriculture and astronomy are just some examples – are very different. This means that each poses different problems, and so data scientists need knowledge about the particular application area.</p>
<p>For example, consider astrophysics and the <a href="https://www.skatelescope.org/">Square Kilometre Array</a> being built on the southern tip of Africa. It will be the world’s largest radio telescope when completed in the mid-2020s. The array of telescopes is said to receive data at one terabyte per second and researchers are typically interested in analysing the masses of data in order to detect tiny signals engulfed in white noise.</p>
<p>In finance, researchers exploit large data bases very differently: for example to learn more about their customers’ credit behaviour. </p>
<p>The most established subfields of data science are statistics and operations research and it might be worthwhile to learn from the established training programmes in these fields. Are universities training enough graduates in these fields? And is that training good enough? </p>
<p>Although students in these fields are well trained academically, many graduates in statistics and operations research lack knowledge about the fields in which they are expected to apply the mathematical techniques. They also tend to battle with real-world problem solving abilities, as well as lacking numerical programming and data handling skills. This is because those skills are <a href="http://asq.org/qic/display-item/index.html?item=38651">not addressed adequately in many curricula</a>.</p>
<p>So, drawing from these failings and the lessons of established data science subfields, what should universities be teaching aspiring data scientists? Here is my list.</p>
<ul>
<li><p>Mathematical and computational sciences, including courses in statistical and probability theory, artificial intelligence, machine learning, operations research, and computer science.</p></li>
<li><p>Programming skills;</p></li>
<li><p>Data management skills;</p></li>
<li><p>Subject matter knowledge in selected fields of application; and</p></li>
<li><p>Professional problem-solving skills.</p></li>
</ul>
<p>This list could be expanded at the postgraduate level. And, whether at undergraduate or postgraduate level, all of these courses should have a practical element. This allows students to develop both professionalism and problem-solving skills. </p>
<p>For instance, at the <a href="http://natural-sciences.nwu.ac.za/bmi">Centre for Business Mathematics and Informatics</a> at South Africa’s North-West University, my colleagues and I have organised a professional training programme that sees students working for six months at a client company to solve a specific industry problem. These problems are mainly in the financial field; for example, models to predict a customer’s ability and willingness to pay, models for improving collections and models for fraud identification.</p>
<p>This helps students to develop the necessary skills to function in the working world, handling real data and applying it to real problems rather than just working at a theoretical level. It also, as a colleague and I have argued in <a href="https://www.tandfonline.com/doi/full/10.1080/08982112.2015.1100454">previous research</a>, helps to close the academia-industry gap and so makes data science more relevant. The BMI programmes have been recognised and commended by international experts.</p>
<p>Data science, as a field, is only going to grow over the coming decades. It is imperative that universities train graduates who can handle enormous tranches of data, work closely with the industries that produce and apply this data – and make data something that can change the world for the better.</p><img src="https://counter.theconversation.com/content/110449/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Riaan de Jongh receives funding from the National Research Foundation and the Department of Science and Technology. </span></em></p>
Data science is going to grow over the coming decades and requires trained graduates who can handle the work.
Riaan de Jongh, Director Centre for BMI, North-West University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/96228
2018-05-30T13:28:50Z
2018-05-30T13:28:50Z
How the SKA telescope is boosting South Africa’s knowledge economy
<figure><img src="https://images.theconversation.com/files/220623/original/file-20180528-80623-wr4ilu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The MeerKAT radio telescope under construction in South Africa's Karoo region.</span> <span class="attribution"><span class="source">Photo courtesy of Dr Fernando Camilo, Chief Scientist at SKA SA</span></span></figcaption></figure><p>We’re living in a time when <a href="http://www.ibmbigdatahub.com/blog/data-raw-material-be-mined">data</a> and <a href="https://www.theguardian.com/public-leaders-network/2012/apr/18/francis-maude-data-raw-material">knowledge</a> have become key resources for economic development. </p>
<p><a href="http://www.eib.org/attachments/efs/the_knowledge_economy_in_europe.pdf">Developed economies</a> have recognised this and have increasingly embraced <a href="http://www.oecd.org/sti/inno/newsourcesofgrowthknowledge-basedcapital.htm">knowledge creation</a> as a way to secure their competitive advantage. They’ve done so by, among other things, <a href="http://blogs.worldbank.org/education/why-education-matters-economic-development">investing more in education</a> with an eye on producing more highly skilled graduates who can thrive in an increasingly technology-driven world.</p>
<p>Some countries have also spent a great deal on huge scientific projects that involve international collaboration. Examples include the <a href="https://home.cern/">European Organisation for Nuclear Research</a> (CERN) in Switzerland and the <a href="https://www.lsst.org/about">Large Synoptic Survey Telescope</a> in Chile, which is a billion dollar project.</p>
<p>And in South Africa, the <a href="http://www.ska.ac.za/about/the-project/">Square Kilometre Array</a> (SKA) project is an example of a promising knowledge-based initiative. It <a href="https://mg.co.za/article/2017-05-19-00-science-technology-and-innovation-transforming-south-africa">could be</a> one of the drivers that contributes to the country’s economic growth.</p>
<p>The SKA is a global project to build the world’s largest radio telescope. It’s co-located in South Africa and Australia. When it’s completed it will cover over 1 million sq metres and will help scientists seek answers to fundamental questions about the nature and origin of the universe.</p>
<p>But the road that leads from a complex project like the SKA to the creation of a thriving local knowledge economy is by no means a straightforward one. In a <a href="http://journals.co.za/docserver/fulltext/sajsci_v114_n3_4_a18.pdf?expires=1525694504&id=id&accname=guest&checksum=0D73AB64708039A06F38A14BBDFD2742">recent paper</a> for the South African Journal of Science, I explored the various factors that impede or encourage the extent to which the process might work. </p>
<p>I found four key factors that determine the extent to which the SKA will be able to contribute to the creation of a robust knowledge economy. These factors are institutions; interrelationships; innovation and individuals. My research suggests that, thanks to these four factors, the project has already borne fruit for South Africa. It has led to good collaboration, sharing of skills and substantial growth of the country’s astronomy community. </p>
<h2>Four pillars</h2>
<p>Firstly, a project like this needs to be supported by sound institutions if it’s to contribute to the long-term, sustainable growth of a knowledge economy. There must be stable and consistent funding and policies at government level. And a country’s broader institutional environment needs to be open and inclusive. This all encourages diverse participation and creative cross-over of ideas. </p>
<p>SKA South Africa has benefited from stable and consistent policies and funding. But, given that SKA SA is publicly funded, policies can sometimes be cumbersome. This can slow things down.</p>
<p>Interrelationships are also crucial. Collaboration and knowledge sharing are extremely important, especially in a field like astronomy. So the cultivation of stronger interrelationships boosts the promotion of knowledge economies. </p>
<p>These interrelationships need to be fostered across multiple disciplines and sectors, as well as across international boundaries. The SKA in South Africa is doing well on this front. Its collaboration with <a href="https://www.ska.ac.za/ska-activities-in-the-northern-cape/developing-small-to-medium-enterprises/">industry partners</a> that range from small, medium and micro-sized enterprises to multinationals has helped <a href="https://www.ska.ac.za/about/highlights/">the spread of scientific and operational expertise</a> among other sectors. </p>
<p>For instance, teachers from the towns closest to the SKA site have received training in robotics through the project. And members of the SKA’s management team have shared their skills to help the municipality with its integrated development planning. </p>
<p>Data collected by the SKA array in a single day would take <a href="https://businesstech.co.za/news/columns/45930/ska-a-game-changer-for-african-tech/">nearly two million years</a> to play back on an iPod. Processing and analysing such astronomical data sets requires both cutting edge technology and collaboration with a diverse set of stakeholders. The SKA in South Africa <a href="http://www.ska.ac.za/wp-content/uploads/2016/11/16_ska_newsletter_mar2012.pdf">is benefiting</a> from both such technology and that level of collaboration.</p>
<p>More fundamentally, the different stakeholders are working together to develop technologies that have <a href="https://businesstech.co.za/news/columns/45930/ska-a-game-changer-for-african-tech/">not yet been invented</a>. </p>
<p>The third factor, innovation, presents an opportunity for developing economies to close the gap with developed economies. But this is only true if ways can be found to commercialise some of the initiatives that emerge. </p>
<p>SKA’s South African arm is taking part in numerous collaborations across sectors that promote knowledge sharing and joint problem solving. Its <a href="https://mg.co.za/article/2015-12-03-ska-gives-high-tech-firms-a-boost">commercialisation strategy</a> is essential for the project to have a great impact on the knowledge economy. </p>
<p>Finally, individuals matter. A project like the SKA must be able to attract, retain and train skilled individuals to establish a viable knowledge economy. Here SKA South Africa has been exemplary. </p>
<p>It has done substantial work to <a href="http://www.engineeringnews.co.za/article/ska-drives-human-capital-development-in-s-africa-africa-ramaphosa-2015-03-02">grow South Africa’s astronomy community</a> through a special human capital development programme that’s aimed at training young people. <a href="http://www.ska.ac.za/students/postgraduate-bursary-conference/">More than 1000</a> young people have benefited from this and similar SKA programmes, and those who’ve been trained are not limited to careers in astronomy: they contribute to the knowledge economy by using their skills in other sectors. </p>
<h2>Forward to the future</h2>
<p>The SKA project is still in its infancy. Science observations are expected to start with a partial telescope array in the mid 2020s. The second phase is set to be completed in the late 2020s.</p>
<p>But, even at this early stage, the project is already contributing to the growth of South Africa’s knowledge economy. The four pillars I explored in my research provide a framework for better understanding how further growth and gains can be encouraged.</p><img src="https://counter.theconversation.com/content/96228/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nishana Bhogal does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
The SKA global project could be a driver that contributes to South Africa’ economic growth.
Nishana Bhogal, PhD Candidate, Graduate School of Business, University of Cape Town
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/88668
2017-12-10T12:10:01Z
2017-12-10T12:10:01Z
Telescopes 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 Cape
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/82849
2017-09-14T16:47:59Z
2017-09-14T16:47:59Z
Ghana is boosting Africa’s ascent to astronomical heights
<figure><img src="https://images.theconversation.com/files/185644/original/file-20170912-19546-1n7hkdm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The refurbished radio telescope in Kutunse, Ghana paves the way for astronomy in Africa.</span> <span class="attribution"><span class="source">SKA</span></span></figcaption></figure><p><em>The <a href="https://theconversation.com/the-science-behind-the-square-kilometre-array-40870">Square Kilometre Array (SKA)</a> is the world’s largest radio telescope project, which will collect data over one million square kilometres from radio astronomy telescopes on the African and Australian continents.
In the long run the two-phased SKA could possibly help scientists answer questions in astrophysics, cosmology and fundamental physics. Phase one of the project entailed setting radio telescopes in <a href="http://www.ska.ac.za/about/the-project/">South Africa</a> and <a href="http://www.ska.gov.au/Pages/default.aspx">Australia</a>. Phase two will include more telescopes being added by partner countries, New Zealand and the eight African countries namely: Botswana, Ghana, Kenya, Mauritius, Madagascar, Mozambique, Namibia and Zambia. The full array should be up and running by 2030, but the first phase is expected to be operational by 2023. The launch of Ghana’s radio telescope is a critical part of this process. Dr Bernard Duah Asabere explained its significance.</em></p>
<p><strong>How did Ghana get involved in the project and how does it fit in?</strong></p>
<p>Ghana has had a redundant satellite communication antenna in Kutunse – a suburb 25 kilometres north-west of the capital, Accra.</p>
<p>Between 2011 and 2017 this antenna has been undergoing refurbishment for use as a radio astronomy telescope. At the end of the first engineering phase, the refurbished telescope is capable of participating in global network observations using a technique known as <a href="http://www.ska.ac.za/science-engineering/avn/">Very Long Baseline Interferometry</a> (VLBI). It also be used in single dish or standalone operational mode.</p>
<p>Interferometry is a technique in which collections of telescopes scattered over a large area function as a single radio telescope. The Very Long Baseline Interferometry technique is most well-known for:</p>
<ul>
<li><p>imaging distant cosmic radio sources, </p></li>
<li><p>tracking spacecraft, and </p></li>
<li><p>for applications in astrometry. </p></li>
</ul>
<p>But the technique can also measure the time differences between the arrival of radio waves from separate antennas to the same source in the sky. This helps astronomers get a better image resolution of an object or a region in the universe. </p>
<p>Put simply, if different telescopes at different locations are all tuned to observe the same source in the sky at the same time, astronomers can get fine details of the specific object being observed.</p>
<p>The countries that make up the African SKA project are each building their own radio telescopes or converting redundant telecommunication dishes so that they function as a network known as the African VLBI Network (AVN). </p>
<p>Ghana now becomes the first country in the African SKA partners besides South Africa to have a <a href="http://www.ska.ac.za/media-releases/ghana-and-south-africa-celebrate-first-success-of-african-network-of-telescopes/">telecommunication antenna</a> converted to realise the African VLBI Network. With Ghana’s telescope now operational, it means that South Africa and Ghana will be able to do joint observations. When the other seven African SKA partner countries get theirs ready, they will join the African’s network. </p>
<p>Kenya, Mozambique and Zambia are contending to add the <a href="https://furtherafrica.com/2017/08/28/eight-african-countries-commit-to-developing-radio-astronomy/">next </a>telescope to the network.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/185643/original/file-20170912-19550-ts7kx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185643/original/file-20170912-19550-ts7kx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185643/original/file-20170912-19550-ts7kx9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185643/original/file-20170912-19550-ts7kx9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185643/original/file-20170912-19550-ts7kx9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185643/original/file-20170912-19550-ts7kx9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185643/original/file-20170912-19550-ts7kx9.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">A full view of the refurbished radio telescope in Ghana that forms part of the Square Kilometre Array project.</span>
<span class="attribution"><span class="source">supplied</span></span>
</figcaption>
</figure>
<p><strong>How did we know the Ghanaian telescope was ready and what will it do?</strong> </p>
<p>Across the globe there are several very long base interferometry networks: Europe has one, as does Australia and America. Any telescope across the world is able to join an observation in one of these networks.</p>
<p>After Ghana re-engineered the antenna into a functional radio astronomy telescope, it needed to do a science commissioning of the facility to see if the refurbishment was successful and it could track and observe astronomical sources in the sky and join international observations. </p>
<p>When Ghana tested its telescope it was able to detect methanol masers, observe pulsars and also succeeded in participating in an observation with 15 other telescopes which form part of the European very long base interferometry network. </p>
<p>Until now South Africa has been the only country on the continent that had been joining in VLBI observations with other countries’ networks because it was the only country with a radio telescope on the continent. </p>
<p>With radio telescopes in Ghana and South Africa, an African network is now given birth to. Aside being a part of the African network, Ghana could join other telescopes on the globe to do science observations. </p>
<p><strong>What is the significance of Ghana’s telescope for astronomy in Africa?</strong></p>
<p>There are many celestial objects to observe in the Universe: planets, masers, galaxies, meteorites, stars and even regions in the sky. And there are global questions that astronomy community is interested in addressing. This includes questions like: is there any life outside earth? Are there other stars that are as prominent as the sun? How did the universe come into being? These are questions that the SKA will attempt to address. </p>
<p>If Africa has its own network, astronomers on the continent can choose what celestial objects and regions it wants to observe. </p>
<p>If we look at most of the existing telescopes across the world, there has been a hole in Africa. Telescopes situated in the Northern hemisphere are unable to see the region of the sky in the southern hemisphere. With an African very long base interferometry network set up, astronomers in Africa can now observe both the northern and southern hemispheres of the sky from the continent. </p>
<p><strong>What is Ghana bringing to the party and what does it hope to get out of this SKA collaboration?</strong></p>
<p>The facility at Kutunse will be used as a science instrument but also as a training facility. Ghana will help the other seven countries that form part of the African network refurbish their unused antennae. </p>
<p>Although this technology is not new and has been done in Australia, Peru, Japan and the UK, no other country in Africa has done this. </p>
<p>For Ghana, developing the skills, regulations and institutional capacity in the partner countries is a vital part of building the square kilometre array on the continent over the next decade. This is because it will optimise African participation in the SKA.</p>
<p>Ghana will build it robust research community in a field never before accessible to the country.</p>
<p>But there is also the prospect of improving the radio astronomy capacity in the country. <a href="http://skatelescope.ca/wp-content/uploads/2017/05/01_asabere.pdf">Ghana’s radio astronomy development strategy</a> forms part of the broader Ghana Science, Technology and Innovation Development Plan.</p><img src="https://counter.theconversation.com/content/82849/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bernard Duah Asabere is the manager and lead local scientist of the Radio Astronomy Observatory. </span></em></p>
Astronomy on the continent has been given a much needed boost with Ghana’s converted radio telescope between it and South Africa, to conduct scientific observations.
Dr. Bernard Duah Asabere, Manager of the Ghana Radio Telescope Observatory, Ghana Space Science and Technology Institute
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/70918
2017-01-12T20:16:26Z
2017-01-12T20:16:26Z
From rural Kenya to a PhD in astronomy: how partnerships made it possible
<figure><img src="https://images.theconversation.com/files/151830/original/image-20170105-18644-1yvwr6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Reuters/Mike Hutchings</span></span></figcaption></figure><p>I grew up in a Kenyan village with dark skies and vivid stars. We admired the sky and listened to stories about it told by the elders. There were few expectations that the children in our village would ever understand the sky’s secrets as this was unimaginable at the time. </p>
<p>I excelled at maths and science, eventually becoming a teacher in the subjects. Then came a Masters degree in Physics, followed by a second Masters through South Africa’s Square Kilometre Array (SKA) project. There the boy who had gazed up at mysterious skies turned into a man who wanted to become an astrophysicist.</p>
<p>But Africa has a challenge: astronomy as a profession is a little known field of science in all but one country, South Africa. Even high school science teachers are often not aware that astronomy is a branch of physics, is therefore a science, and could be presented to pupils as a viable career option. The construction of the mid frequency part of the SKA in South Africa, in partnership with eight other African countries, means the continent needs to encourage, produce and nurture young astrophysicists.</p>
<p>Very few African universities offer postgraduate degrees in astronomy. Most that do are based in South Africa; the others include the University of Mauritius and Kenya’s University of Nairobi.</p>
<p>This gap in knowledge, information and study is now being bridged by joint UK-South Africa project that trains students from Africa in the field of astronomy with a focus on radio astronomy. I am a student of the <a href="http://www.dara-project.org/">Development in Africa through Radio Astronomy</a> project currently studying towards my PhD at the <a href="http://www.ast.leeds.ac.uk/">University of Leeds</a>. The funding stems from the UK’s <a href="http://www.newtonfund.ac.uk/">Newton Fund</a> and is matched by funding from South Africa’s <a href="http://www.dst.gov.za/">department of science and technology</a>. </p>
<p>It’s a good example of how training and partnerships can help to build the scientists Africa needs to establish itself as a key player in astronomy, radio astronomy and astrophysics.</p>
<h2>How the project works</h2>
<p>DARA conducted training programmes in Kenya and Zambia during 2015 building on a concurrent programme in Ghana funded by the UK’s Royal Fund. There it equipped 40 students with the fundamentals of radio astronomy. It was a challenging, competitive and captivating two months consisting of four different training units. We were trained in the technical aspects of radio astronomy as well as learning about data collection and reduction. We collected and analysed data from a nearby astrophysical object – the sun, for example.</p>
<p>Of those 40 trainees, six – myself among them – were sponsored for further postgraduate studies in the UK; ten others were funded to study further in South Africa. The selection was made with partner institutions in each participating country.</p>
<p>Leeds is one of four participating UK universities. The others are the University of Manchester, University of Hertfordshire and Oxford University. These are all centres of excellence. We will also, during our studies, spend some time in South Africa supervised by a South African collaborator. This is important preparation for future collaborations, which are <a href="https://theconversation.com/why-its-time-african-researchers-stopped-working-in-silos-59539">crucial in science</a>.</p>
<p>As trainees, we’ve enjoyed interactions with senior research scientists and presentations from renowned academics. We present our work to each other and develop the skills we’ll need to be working scientists. We’re also looking forward to welcoming fellow students from countries such as Namibia, Botswana, Mauritius, Madagascar and Mozambique as the project expands further across the continent.</p>
<p>This training formula has the potential to inspire and empower many more individuals across Africa. And the benefits won’t be felt just in the field of astronomy. The skills my colleagues and I are developing are widely applicable. They can be used in a number of areas: research, computing, telecommunications, land management and even business.</p>
<h2>Preparing Africa for the SKA</h2>
<p>Equally important is DARA’s role in preparing Africa ahead of the completion of the SKA, the <a href="http://www.space.com/15883-worlds-largest-radio-telescope-ska-array.html">world’s largest radio telescope</a>. It is partially hosted in South Africa. SKA-Africa is also funding the conversion of the redundant satellite earth stations in Africa into radio telescopes that will form a <a href="http://www.ska.ac.za/science-engineering/avn">network of telescopes</a> called the African VLBI (Very Long Baseline Interferometry) Network – a technique that will simulate a telescope the size of Africa.</p>
<p>These are major investments in science. It’s important that preparations be made for their proper maintenance and successful operation – and that requires trained radio astronomers to do the work. The amount of data to be collected from these facilities is also large; if this collection is to be thorough and successful it will require properly trained big data managers and researchers. This is why DARA is preparing people like me for the future of African astronomy.</p>
<p>These telescopes can be seen as a sign of trust that the rest of the world has placed in Africa. They are capital intensive science facilities. With proper training programmes and the development of more African astronomers, the continent can repay this trust many times over.</p><img src="https://counter.theconversation.com/content/70918/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Willice O. Obonyo is affiliated with the Astrophysics group of University of Leeds. </span></em></p>
Very few African universities offer postgraduate degrees in astronomy. This gap in knowledge and training can be addressed through international partnerships and collaboration.
Willice O. Obonyo, PhD student (Radio Astronomy), University of Leeds
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/64381
2016-10-18T14:32:51Z
2016-10-18T14:32:51Z
Radio galaxies: the mysterious, secretive “beasts” of the Universe
<figure><img src="https://images.theconversation.com/files/141448/original/image-20161012-13485-ao5jja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Jets generated by supermassive black holes at the centers of galaxies can transport huge amounts of energy across great distances.</span> <span class="attribution"><span class="source">REUTERS/X-ray: NASA/CXC/Tokyo Institute of Technology/J.Kataoka et al</span></span></figcaption></figure><p>Most pictures of galaxies that you see, such as the <a href="http://hubblesite.org/gallery/album/">beautiful images</a> from the <a href="http://hubblesite.org/">Hubble Space Telescope</a>, are optical images. These are made using telescopes which detect light in the same wavelength range that our eyes see. However, scientists can design telescopes which use different parts of the electromagnetic spectrum, such as shorter-wavelength ultraviolet light or longer-wavelength infrared and radio emission. </p>
<p>When we use a <a href="http://www.ska.ac.za/about/faqs/#toggle-id-3">radio telescope</a> to look at galaxies, we find that some have pairs of giant jets extending from their centre out into space.</p>
<p>Jets – powerful, lightning fast particles – are the beasts of the universe, far larger than anything visible in optical image. They often stretch to many millions of times the size of the galaxy itself. There is often no evidence of these jets in the optical images.</p>
<p>They also don’t give up their secrets easily. We have a good idea what jets are and how they’re formed. But, for example, we don’t understand yet what causes these jets to start in the first place. That’s where the powerful <a href="https://www.skatelescope.org/">Square Kilometre Array</a> (SKA) radio telescope that’s currently being built in South Africa enters the picture. Its size and scope can help scientists probe more deeply than ever before.</p>
<h2>The making of a jet</h2>
<p>So how are jets formed? </p>
<p>Galaxies come in many different shapes and sizes, and all galaxies of any reasonable size have a supermassive black hole at their centre. The larger the galaxy, the larger the black hole at its centre. These black holes are many millions of times the mass of the sun. In most galaxies they simply sit passively at the heart of the galaxy. </p>
<p>In some galaxies, however, gas and dust is falling into this supermassive black hole causing vast quantities of energy to be released. This sometimes results in hugely energetic streams of particles – channelled by twisted magnetic fields – being ejected from the galaxy centre. </p>
<p>These powerful fountains of particles are spewed out into space at nearly the speed of light. They form the impressive jets visible in radio images. These particles travel through space for many millions of kilometres until they are eventually slowed down and stopped when they interact with old clouds of gas left over from when the galaxy formed. These jets are immensely powerful and can be thousands of light years across. </p>
<p>Although we understand the processes forming the jets, we don’t know what causes these jets to start in the first place. </p>
<p>Some observations suggest they may be triggered when two galaxies collide, thrusting large quantities of gas and dust into the path of the supermassive black hole at the galactic centre. But this certainly does not seem to be the case for all radio galaxies. There is evidence that some radio galaxies stop ejecting the streams of energetic particles, then start again many thousands of years later. However we don’t know if all radio galaxies go through several active phases like this, or if this is unusual. </p>
<h2>Still so much to learn</h2>
<p>It takes a long time for radio galaxies to grow so large – sometimes up to tens to hundreds of millions of years. This means scientists can’t study radio jets by watching one grow. Instead we have to look at lots of different radio galaxies at different stages in their life cycles. </p>
<p>And understanding radio galaxy jets is important. Because they’re so powerful, these jets have a strong influence on both the galaxy they come from and its surroundings. </p>
<p>From building models of how galaxies evolve with time and comparing them to observations, scientists know that something must be dramatically slowing down the rate at which stars form in the most massive galaxies. Scientists believe that radio jets may be responsible. They heat the gas within the galaxy, preventing it from forming into stars. </p>
<p>However, this process is not well understood. For example, there is also evidence that radio jets may increase the rate of star formation in some galaxies, by compressing gas into dense clouds. Understanding how radio jets interact with their host galaxies and wider environment is key to understanding how galaxies form and evolve with time. This is one of astronomy’s key unanswered questions.</p>
<p>The completion of the SKA, which is being built in South Africa and Australia, will help answer these questions.</p>
<h2>Solving mysteries</h2>
<p>When the SKA is fully operational – sometime after 2020 – it will observe up to a billion galaxies. That includes some of the very first galaxies to form. Using these observations, astronomers should be able to unlock the secrets of radio galaxies. </p>
<p>The <a href="https://www.ska.ac.za/science-engineering/meerkat/">MeerKAT telescope</a>, a precursor to the SKA, is already taking data at the South African site, in the remote Karoo, and will allow us to start answering some of these questions next year. </p>
<p>Perhaps these mysterious beasts of the Universe won’t remain a mystery much longer.</p><img src="https://counter.theconversation.com/content/64381/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Imogen Whittam works for SKA South Africa. She receives funding from SKA South Africa. She is affiliated with SKA South Africa and the University of the Western Cape. </span></em></p>
It’s difficult to get jets - powerful, lightning fast particles - to give up their secrets. The new Square Kilometre Array radio telescope could hold the key to solving jets’ mysteries.
Imogen Whittam, Post-doctoral researcher in Astrophysics, University of the Western Cape
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/65246
2016-09-28T16:19:01Z
2016-09-28T16:19:01Z
Africa’s MeerKAT ‘first light’ images have blown all expectations
<figure><img src="https://images.theconversation.com/files/138487/original/image-20160920-12453-b7emdu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="http://www.ska.ac.za/gallery/meerkat/">SKA South Africa</a></span></figcaption></figure><p>Something hugely important is happening in a vast, quiet stretch of South Africa’s Northern Cape province. A new radio telescope operating at just a quarter of its full power is revealing the universe’s secrets one image at a time.</p>
<p>MeerKAT will ultimately become part of the Square Kilometre Array (SKA) telescope. Once it’s completed some time in the decade following 2020, the SKA will be the <a href="http://www.space.com/15883-worlds-largest-radio-telescope-ska-array.html">world’s largest radio telescope</a>. The project is shared between South Africa and Australia. It’s not just its size that sets it apart from other radio telescopes but also sensitivity and speed. At full power, the SKA <a href="http://www.space.com/15883-worlds-largest-radio-telescope-ska-array.html">will have</a> 50 times the sensitivity and 10,000 times the survey speed of the best existing telescopes.</p>
<p>It will see more, and see it faster. It can explore the universe and answer some of humanity’s biggest scientific questions – like, “Is there life out there?” and “How are galaxies formed?”</p>
<p>All of this lies some time in the future. But already, MeerKAT is yielding remarkable results. </p>
<h2>Off to a good start</h2>
<p>MeerKAT currently comprises 16 dishes (of an eventual 64) functioning as a telescope array – a radio telescope works by effectively linking smaller dishes together and operating as one. </p>
<p>These 16 dishes, known collectively as Array Release 1, recently embarked on their first assignment. It was an amazing start: Array Release 1 found 1300 galaxies in a patch of sky that was previously thought to contain only 70. That’s hundreds of new galaxies to be studied and understood, and greatly adds to our knowledge of the universe. </p>
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<img alt="" src="https://images.theconversation.com/files/138501/original/image-20160920-12475-o5eluu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/138501/original/image-20160920-12475-o5eluu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138501/original/image-20160920-12475-o5eluu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138501/original/image-20160920-12475-o5eluu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138501/original/image-20160920-12475-o5eluu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138501/original/image-20160920-12475-o5eluu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138501/original/image-20160920-12475-o5eluu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">View showing 10% of the full MeerKAT First Light radio image. More than 200 astronomical radio sources (white dots) are visible in this image. Before MeerKAT only five were known (indicated by violet circles). This image spans about the area of the Earth’s moon.</span>
<span class="attribution"><a class="source" href="http://www.ska.ac.za/gallery/meerkat/">SKA South Africa</a></span>
</figcaption>
</figure>
<p>Because MeerKAT specialises in radio galaxies, it can peer through the thick layers of dust that surround such galaxies. Astronomer Michael Rich, who wasn’t part of the study, <a href="http://news.nationalgeographic.com/2016/07/radio-telescope-new-galaxies-meerkat-south-africa-space-science/">told National Geographic</a>:</p>
<blockquote>
<p>In some cases, the radio galaxy can have a great deal of obscuring dust, and you wouldn’t be able to see anything – or almost anything – with an optical telescope.</p>
</blockquote>
<p>These “first light” images are extremely exciting, whether for seasoned astronomers or ordinary people who crave more information about the world “out there”.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/w_q6kB2nCdw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The SKA, of which the MeerKAT is part, is searching for intergalactic answers.</span></figcaption>
</figure>
<h2>Massive infrastructure</h2>
<p>There’s more than <a href="https://theconversation.com/the-science-behind-the-square-kilometre-array-40870">pure science</a> to any project of this scope. It takes remarkable engineering to bring any radio telescope to life, let alone what will become the world’s largest.</p>
<p>Each of MeerKAT’s completed 64 dishes will be 13.5 metres, or about 40 feet, in diameter. The dishes are accompanied by a plethora of cryogenic coolers, receivers, digitisers and other electronic systems.</p>
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<a href="https://images.theconversation.com/files/138456/original/image-20160920-11100-cjw78j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/138456/original/image-20160920-11100-cjw78j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/138456/original/image-20160920-11100-cjw78j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=291&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138456/original/image-20160920-11100-cjw78j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=291&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138456/original/image-20160920-11100-cjw78j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=291&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138456/original/image-20160920-11100-cjw78j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=365&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138456/original/image-20160920-11100-cjw78j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=365&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138456/original/image-20160920-11100-cjw78j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=365&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 MeerKAT’s massive dishes.</span>
<span class="attribution"><a class="source" href="http://www.ska.ac.za/gallery/meerkat/">SKA South Africa</a></span>
</figcaption>
</figure>
<p>It’s a challenge to get all of this equipment to work together in a fully integrated array. That’s why the telescope is being commissioned in phases: it allows any technical problems to be identified and resolved as early as possible. </p>
<p>As the “first light” images reveal, everything is functioning smoothly as the MeerKAT begins its sky-searching work.</p>
<h2>Space for science in action</h2>
<p>One of the important features of the SKA and MeerKAT is that it’s a massive, multinational endeavour. There are around 200 technicians, scientists and engineers working on the project. They come from all over the world and are collaborating with industry to build the technologies, hardware and software systems for MeerKAT telescope. </p>
<p>It’s not just about the construction, though. Scientists are also getting the chance to test their theories using MeerKAT’s infrastructure.</p>
<p>I am part of a team led by <a href="https://www.uwc.ac.za/Biography/Pages/Mario-Santos.aspx">Professor Mario Santos</a> of the University of the Western Cape involved in a large survey that will be conducted with MeerKAT. The team consists of scientists from South African and international institutions. Our goal is to do breakthrough cosmology and study the many new galaxies that will be detected.</p>
<p>Recently a new scientific technique called <a href="http://www.caastro.org/research/evolving/intensitymapping">HI Intensity Mapping</a> has emerged as a powerful and promising probe for cosmology with radio telescopes. It involves trying to map the universe’s neutral hydrogen content.</p>
<p>MeerKAT provides an exciting opportunity to put this science to the test. We’re seeking an extremely weak signal, much weaker than the galaxy and the contributions that the instrument adds to the data. My recent work has involved demonstrating that you can “clean” out all these other contributions to access the very weak hydrogen signal. Once we’re able to locate this crucial signal, we’ll be able to understand much more about the universe.</p>
<h2>Staring at the sky</h2>
<p>It’s not just those who are directly involved in the project who are excited about what MeerKAT has to offer. Just after Array Release 1, about 150 astronomers – two thirds of them from South Africa – <a href="http://meerkat2016.ska.ac.za/programme">met</a> to discuss and update the MeerKAT science programme in Stellenbosch. </p>
<p>Broadly, this programme will consist of two major elements. The first involves approved large surveys of the sky. These will peer into deep space; they’ll range from shallow and wide to deep and small, covering large volumes of space containing many, many galaxies. The images they’ll capture will deepen our understanding of what the universe contains, how it’s structured and how it works.</p>
<p>The second element is open time: time reserved for astronomers to propose new and interesting observations that can then be conducted using the MeerKAT. This encourages more research and could lead to even more of the universe’s secrets being revealed.</p>
<h2>Much more to come</h2>
<p>The “first light” images are just the beginning. Even at a quarter of its full strength MeerKAT – and ultimately the SKA project – seems set to prove that the sky really is the limit for what we can learn about our universe.</p><img src="https://counter.theconversation.com/content/65246/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Prina Patel works for SKA South Africa. She receives funding from SKA South Africa. She is affiliated with SKA South Africa and The University of the Western Cape. </span></em></p>
What’s particularly exciting about “first light” images from South Africa’s MeerKAT radio telescope is that they prove Africa is a rising star in the world of astronomy.
Prina Patel, SKA Postdoc in Observational Cosmology, University of the Western Cape
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/54583
2016-02-12T09:26:15Z
2016-02-12T09:26:15Z
Gravitational waves: will the global south provide the next pulse of gravity research?
<figure><img src="https://images.theconversation.com/files/111285/original/image-20160212-29192-16yu5pg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This is a new era of physics and astronomy - and scientists all over the globe, including in Africa, have a role to play.</span> <span class="attribution"><span class="source">NASA</span></span></figcaption></figure><p>A little over a century ago, on 25 November 1915, Albert Einstein published a paper entitled <a href="http://www.academia.edu/375613/Einsteins_Original_Paper_on_General_Relativity">“Die Feldgleichungen der Gravitation”</a>. Its contents would change the world forever. </p>
<p>Like any good scientific theory, Einstein’s General Relativity not only explained the shortcomings of its predecessor, in this case <a href="http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html">Newtonian gravity</a>, it also made predictions of new and unexpected phenomena. These included the bending of light by massive objects, the existence of black holes, the slowing down of time in strong gravitational fields and the very framework for the cosmology of the universe. All of these have withstood a century of <a href="http://physics.ucr.edu/%7Ewudka/Physics7/Notes_www/node97.html">intense scrutiny</a>. But for 100 years one particular prediction in Einstein’s theory of Gravity eluded the most ingenious testing.</p>
<p>That changed on 11 February 2016 with the <a href="https://www.ligo.caltech.edu/news/ligo20160211">news that gravitational waves</a> have been discovered. As so often happens in astronomy research, the real event took place over a billion years ago. The detection was in September 2015. But the full gravity of the situation is only being revealed now: this is a new era in astronomy and physics. </p>
<h2>The signal that started it all</h2>
<p>On 14 September 2015 the <a href="https://www.ligo.caltech.edu/">Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)</a>, a newly upgraded, purpose-built gravitational wave detection experiment based in the USA, received a signal from a binary system of two massive black holes merging into a single larger one, 1.2 billion light years away. The final front’s here.</p>
<p>This event was so cataclysmic that the gravitational wave released in the final moments of the binary system’s mortal dance produced the first ever observed gravitational wave signal. It was so large that LIGO scientists report being able to visually <a href="https://twitter.com/PhysRevLett/status/697815592062074881">“see” the signal in the data</a>. </p>
<p>To put this in perspective, the level of accuracy needed to see this tiny ripple in spacetime required measuring a change in length of a 4km long channel the size of a fraction of the diameter of a proton! The level of certainty in this result is given, in physics terms, as a 5.1 sigma event. In simple terms, the likelihood that this is a coincidence is less than 1 in 3.5 million. </p>
<p>And it all goes back to Einstein.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/111282/original/image-20160212-4413-474ify.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/111282/original/image-20160212-4413-474ify.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=789&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111282/original/image-20160212-4413-474ify.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=789&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111282/original/image-20160212-4413-474ify.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=789&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111282/original/image-20160212-4413-474ify.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=991&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111282/original/image-20160212-4413-474ify.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=991&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111282/original/image-20160212-4413-474ify.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=991&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Albert Einstein.</span>
<span class="attribution"><span class="source">Reuters</span></span>
</figcaption>
</figure>
<h2>Evasive waves</h2>
<p>Although their existence had never been directly detected, gravitational waves - ripples in the very fabric of spacetime - are so-well studied that they are <a href="http://www.aei.mpg.de/%7Eschutz/download/lectures/AzoresCosmology/Schutz.AzoresLecture1.pdf">taught even to undergraduate students</a>.</p>
<p>So why are they so difficult to detect? One reason is that, unlike light, gravitational waves are incredibly weakly interacting and can pass through most matter, of arbitrary density, unhindered. A second one is that, unlike the electric force field which can be felt by individual charges in a detector, the gravitational field is <a href="https://en.wikipedia.org/wiki/Tidal_force">tidal in nature</a> and requires extensive apparatus to detect it. </p>
<p>Taken together, these would merely imply that any detection of gravitational waves would take some of the largest, most sensitive experimental apparatus ever built. Difficult, but surely not that difficult. After all we’ve built the <a href="http://home.cern/topics/large-hadron-collider">Large Hadron Collider</a> and discovered <a href="http://science.howstuffworks.com/higgs-boson.htm">the Higgs</a>. No, there is one more crucial element to this detection: luck. </p>
<p>Producing a gravitational wave large enough for us to detect out here in the galactic suburbs takes some of the most cataclysmic events in the universe, events matched in their violence only by how rare they are. Until now.</p>
<h2>Could Africa be next?</h2>
<p>Today, thanks to the remarkable work of more than 1000 scientists involved in LIGO, there is certainty: Einstein was right, again. </p>
<p>His theory about gravitational waves sparked a huge debate when it was first published, engaging some of the world’s most famous scientists. The <a href="https://www.youtube.com/watch?v=TWqhUANNFXw">beautiful chirp</a> heard across the world on 11 February 2016 was the final word in this particular century-long conversation. However, the next phase of the conversation is far from over. </p>
<p>Physicists and astronomers have learnt so much, yet our work is far from done. The next frontier is here. Where will be the next big announcement be made in this new era? Who will write the next chapter in this intergenerational dialogue? Today is a day for boldness. So allow us, as African scientists, to be bold. With the <a href="https://www.skatelescope.org/">Square Kilometre Array</a> project to be constructed across Africa and Australia, the global South and indeed Africa itself is poised to provide the next pulse of gravity research. Our time has come.</p><img src="https://counter.theconversation.com/content/54583/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amanda Weltman receives funding from the National Research Foundation of South Africa and the Department of Science and Technology of South Africa. </span></em></p><p class="fine-print"><em><span>Jeff Murugan receives funding from the National Research Foundation of South Africa. </span></em></p>
The discovery of gravitational waves has ushered in a new era in astronomy and physics. Where will the next big discovery be made? There’s no reason for it not to be Africa.
Amanda Weltman, South African Research Chair in Physical Cosmology, Department of Mathematics and Applied Mathematics, University of Cape Town
Jeff Murugan, Associate Professor of Mathematical Physics, University of Cape Town
Licensed as Creative Commons – attribution, no derivatives.