tag:theconversation.com,2011:/us/topics/nuclei-21525/articlesnuclei – The Conversation2018-05-02T10:40:36Ztag:theconversation.com,2011:article/939162018-05-02T10:40:36Z2018-05-02T10:40:36ZElements from the stars: The unexpected discovery that upended astrophysics 66 years ago<figure><img src="https://images.theconversation.com/files/217062/original/file-20180501-135840-1g8smw7.png?ixlib=rb-1.1.0&rect=0%2C97%2C952%2C793&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">New heavy nuclei are constantly generated in stars and other astronomical bodies.</span> <span class="attribution"><span class="source">Erin O’Donnell</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Nearly 70 years ago, astronomer Paul Merrill was watching the sky through a telescope at <a href="https://www.mtwilson.edu/">Mount Wilson Observatory</a> in Pasadena, California. As he observed the light coming from a distant star, he saw signatures of the element technetium.</p>
<p>This was completely unexpected. Technetium has no stable forms – it’s what physicists call an <a href="https://en.wikipedia.org/wiki/Synthetic_element">“artificial” element</a>. As Merrill himself put it with a bit of understatement, “<a href="https://doi.org/10.1126/science.115.2992.479">It is surprising to find an unstable element in the stars</a>.”</p>
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<a href="https://images.theconversation.com/files/217074/original/file-20180501-135803-wsicre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/217074/original/file-20180501-135803-wsicre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/217074/original/file-20180501-135803-wsicre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=799&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217074/original/file-20180501-135803-wsicre.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=799&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217074/original/file-20180501-135803-wsicre.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=799&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217074/original/file-20180501-135803-wsicre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1004&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217074/original/file-20180501-135803-wsicre.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1004&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217074/original/file-20180501-135803-wsicre.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1004&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Paul W. Merrill standing at the spectrograph mounted on the 60-inch telescope at Mount Wilson Observatory.</span>
<span class="attribution"><a class="source" href="http://hdl.huntington.org/cdm/singleitem/collection/p15150coll2/id/1584/rec/11">Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, California</a></span>
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<p>Any technetium present when the star formed should have transformed itself into a different element, such as ruthenium or molybdenum, a very long time ago. As an artificial element, someone must have recently created the technetium Merrill spotted. But who or what could have done that in this star?</p>
<p>On May 2, 1952, Merrill reported his <a href="https://doi.org/10.1126/science.115.2992.479">discovery in the journal Science</a>. Among the three interpretations offered by Merrill was the answer: Stars create heavy elements! Not only had Merrill explained a puzzling observation, he had also opened the door to understand our cosmic origins. Not many discoveries in science completely change our view of the world – but this one did. The newly revealed picture of the universe was simply mind-blowing, and the repercussions of this discovery are still driving nuclear science research today.</p>
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<a href="https://images.theconversation.com/files/217099/original/file-20180501-135848-hyzcan.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/217099/original/file-20180501-135848-hyzcan.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/217099/original/file-20180501-135848-hyzcan.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=414&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217099/original/file-20180501-135848-hyzcan.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=414&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217099/original/file-20180501-135848-hyzcan.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=414&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217099/original/file-20180501-135848-hyzcan.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=520&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217099/original/file-20180501-135848-hyzcan.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=520&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217099/original/file-20180501-135848-hyzcan.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=520&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Technetium nuclei are transformed into Ruthenium or Molybdenum within a few million years – so if you spot them now, they can’t be left from the Big Bang billions of years ago.</span>
<span class="attribution"><span class="source">Erin O’Donnell, Michigan State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>Where do elements come from?</h2>
<p>In the early 1950s, it was still unclear how the elements that make up our universe, our solar system, even our human bodies, were created. Initially, the most popular scenario was that they were all made in the Big Bang.</p>
<p>First alternative scenarios were developed by renowned scientists of the time, like <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/1967/bethe-facts.html">Hans Bethe</a> (Nobel Prize in Physics, 1967), <a href="https://www.atomicheritage.org/profile/carl-friedrich-von-weizs%C3%A4cker">Carl Friedrich von Weizsäcker</a> (Max-Plank Medal, 1957), and <a href="https://www.britannica.com/biography/Fred-Hoyle">Fred Hoyle</a> (Royal Medal, 1974). But no one really had come up with a convincing theory for the origin of the elements – until Paul Merrill’s observation. </p>
<p>Merrill’s discovery marked the birth of a completely new field: stellar nucleosynthesis. It’s the study of how the elements, or more accurately their atomic nuclei, are synthesized in stars. It didn’t take long for scientists to start trying to figure out exactly what the process of element synthesis in stars entailed. This is where nuclear physics had to come into play, to help explain Merrill’s amazing observation.</p>
<h2>Fusing nuclei in the heart of a star</h2>
<p>Brick by brick, element by element, nuclear processes in stars take the abundant hydrogen atoms and build heavier elements, from helium and carbon all the way to technetium and beyond. </p>
<p>Four prominent nuclear (astro)physicists of the time worked together, and in 1957 published the “<a href="https://journals.aps.org/rmp/pdf/10.1103/RevModPhys.29.547">Synthesis of the Elements in Stars</a>”: <a href="https://www.britannica.com/biography/Margaret-Burbidge">Margaret Burbidge</a> (Albert Einstein World Award of Science, 1988), <a href="http://www.phys-astro.sonoma.edu/brucemedalists/burbidgeg/index.html">Geoffrey Burbidge</a> (Bruce Medal, 1999), <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/1983/fowler-facts.html">William Fowler</a> (Nobel Prize in Physics, 1983), and <a href="https://www.britannica.com/biography/Fred-Hoyle">Fred Hoyle</a> (Royal Medal, 1974). The publication, known as B2FH, still remains a reference for describing astrophysical processes in stars. <a href="http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/cameron-a-g-w.pdf">Al Cameron</a> (Hans Bethe Prize, 2006) in the same year independently arrived at the same theory in his paper “<a href="https://doi.org/10.1086/127051">Nuclear Reactions in Stars and Nucleogenesis</a>.”</p>
<p>Here’s the story they put together.</p>
<p>Stars are heavy. You’d think they would completely collapse in upon themselves because of their own gravity – but they don’t. What prevents this collapse is nuclear fusion reactions happening at the star’s center.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/217106/original/file-20180501-135810-6g81mr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/217106/original/file-20180501-135810-6g81mr.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/217106/original/file-20180501-135810-6g81mr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=855&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217106/original/file-20180501-135810-6g81mr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=855&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217106/original/file-20180501-135810-6g81mr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=855&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217106/original/file-20180501-135810-6g81mr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1074&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217106/original/file-20180501-135810-6g81mr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1074&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217106/original/file-20180501-135810-6g81mr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1074&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">When atomic nuclei collide, they sometimes fuse, forming new elements.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:FusionintheSun.svg">Borb</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Within a star are billions and billions of atoms. They’re zooming all around, sometimes colliding with one another. Initially the star is too cold, and when atoms’ nuclei collide they simply bounce off each other. As the star compresses because of its gravity, though, the temperature at its center increases. In such hot conditions, now when nuclei run into each other they have enough energy to merge together. This is what physicists call a <a href="https://en.wikipedia.org/wiki/Nuclear_fusion">nuclear fusion reaction</a>.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/217066/original/file-20180501-135817-rqu0m6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/217066/original/file-20180501-135817-rqu0m6.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/217066/original/file-20180501-135817-rqu0m6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=642&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217066/original/file-20180501-135817-rqu0m6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=642&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217066/original/file-20180501-135817-rqu0m6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=642&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217066/original/file-20180501-135817-rqu0m6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=807&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217066/original/file-20180501-135817-rqu0m6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=807&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217066/original/file-20180501-135817-rqu0m6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=807&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fusion reactions happen in different parts of a star. Technetium is created in the shell.</span>
<span class="attribution"><a class="source" href="http://www.eso.org/public/images/eso0729a/">ESO</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>These nuclear reactions serve two purposes.</p>
<p>First, they release energy that heats the star, providing the outward pressure that prevents its gravitational collapse and keeps the star in balance for billions of years. Second, they <a href="http://www.jinaweb.org/movies/pp_chain.html">fuse light elements into heavier ones</a>. And slowly, starting with hydrogen and helium, stars will make the technetium that Merrill observed, the calcium in our bones and the gold in our jewelry.</p>
<p>Many different nuclear reactions are responsible for making all this happen. And they’re extremely difficult to study in the laboratory because nuclei are hard to fuse. That’s why, for more than six decades, <a href="https://doi.org/10.1007/s00016-018-0216-0">nuclear physicists have continued to work</a> to get a handle on the nuclear reactions that drive the stars.</p>
<h2>Astrophysicists still untangling element origins</h2>
<p>Today there are many more ways to observe the signatures of element creation throughout the universe.</p>
<p>Very old stars record the composition of the universe way back at the time of their formation. As more and more stars of varying ages are found, their compositions begin to tell the <a href="https://doi.org/10.1063/PT.3.3815">story of element synthesis in our galaxy</a>, from its formation shortly after the Big Bang to today.</p>
<p>And the more researchers learn, the more complex the picture gets. In the last decade, observations provided evidence for a much broader range of element-creating processes than anticipated. For some of these processes, we do not even know yet in what kind of stars or stellar explosions they occur. But astrophysicists think all these stellar events have contributed their characteristic mix of elements into the swirling dust cloud that ultimately became our solar system.</p>
<p>The most recent example comes from a <a href="https://theconversation.com/cosmic-alchemy-colliding-neutron-stars-show-us-how-the-universe-creates-gold-86104">neutron-star merger event</a> tracked <a href="https://theconversation.com/ligo-announcement-vaults-astronomy-out-of-its-silent-movie-era-into-the-talkies-85727">by gravitational and electromagnetic observatories</a> around the world. This observation demonstrates that even merging neutron stars make a large contribution to the production of heavy elements in the universe – in this case the so-called Lanthanides that include elements such as Terbium, Neodynium and the Dysprosium used in cellphones. And just like at the time of Merrill’s discovery, nuclear scientists around the world are scrambling, working overtime at their accelerators, to figure out what nuclear reactions could possibly explain all these new observations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/217108/original/file-20180501-135825-hhntgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/217108/original/file-20180501-135825-hhntgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/217108/original/file-20180501-135825-hhntgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=380&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217108/original/file-20180501-135825-hhntgj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=380&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217108/original/file-20180501-135825-hhntgj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=380&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217108/original/file-20180501-135825-hhntgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=477&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217108/original/file-20180501-135825-hhntgj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=477&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217108/original/file-20180501-135825-hhntgj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=477&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Modern nucleosynthesis experiments, like those of the authors, are run on nuclear physics equipment including particle accelerators.</span>
<span class="attribution"><a class="source" href="http://nscl.msu.edu/">National Superconducting Cyclotron Laboratory</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Discoveries that change our view of the world don’t happen every day. But when they do, they can provide more questions than answers. It takes a lot of additional work to find all the pieces of the new scientific jigsaw puzzle, put them together step by step and eventually arrive at a new understanding. Advanced astronomical observations with modern telescopes continue to reveal more and more secrets hidden in distant stars. State-of-the-art accelerator facilities study the nuclear reactions that create elements in stars. And sophisticated computer models put it all together, trying to recreate the parts of the universe we see, while reaching out toward the ones that are still hiding until the next major discovery.</p><img src="https://counter.theconversation.com/content/93916/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Artemis Spyrou receives funding from the National Science Foundation and the Department of Energy/National Nuclear Security Administration. </span></em></p><p class="fine-print"><em><span>Hendrik Schatz receives funding from National Science Foundation and Department of Energy Office of Science.</span></em></p>People long assumed all the elements we see now were created during the Big Bang. But on May 2, 1952, an astronomer reported spotting new elements coming from an old star and changed our origin story.Artemis Spyrou, Associate Professor of Nuclear Physics, Michigan State UniversityHendrik Schatz, University Distinguished Professor of Nuclear Astrophysics, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/652842016-09-20T18:13:30Z2016-09-20T18:13:30ZAfrica’s universities can shrug off history and stage science revolutions<figure><img src="https://images.theconversation.com/files/138073/original/image-20160916-6342-1c5hkqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The sky is the limit for African science when universities work together.</span> <span class="attribution"><span class="source">Mohamed Nureldin Abdallah/Reuters</span></span></figcaption></figure><p><em>South Africa’s <a href="https://www.uwc.ac.za/Pages/default.aspx">University of the Western Cape (UWC)</a> has been ranked <a href="http://www.timeslive.co.za/scitech/2016/09/07/Sky-science-sees-University-of-the-Western-Cape-beat-big-names-in-Nature-ranking">number one</a> for Physical Science in Africa by top journal <a href="http://www.nature.com/nature/index.html">Nature</a>. Nico Orce, an associate professor with UWC’s nuclear physics and nuclear astrophysics group, tells The Conversation Africa what lessons there are for other universities on the continent – and why there’s more work to be done.</em></p>
<p><strong>UWC still serves a historically disadvantaged community and is less well-funded than many previously white universities in South Africa. Against this backdrop, what did it take for you, your colleagues and your students to get this far?</strong></p>
<p>Being ranked number one on the continent is strongly linked to the <a href="https://www.ska.ac.za">Square Kilometre Array (SKA)</a> telescope being built in South Africa. A number of UWC’s scientists are very involved in this project. </p>
<p>Smart strategic planning and a real push for funding helped to stimulate the physical sciences at UWC. That energy attracted more and more talented researchers, including post-doctoral candidates. This is a crucial way to speed up transformation: bringing in highly skilled researchers from all over the country and the world to train a new generation of local scientists.</p>
<p><strong>The sciences have had a good year at UWC. Your group is also about to become the first from an African institution to <a href="http://www.netwerk24.com/ZA/Tygerburger/Nuus/uwc-students-on-the-way-to-cern-20160830-2">lead an experiment at CERN</a>, the <a href="https://home.cern/about">European Organisation for Nuclear Research</a>. How did that happen?</strong></p>
<p>When I was finishing my degree in Fundamental Physics back in Spain I convinced some of my friends to attend a summer school at CERN. We asked the professor in charge of international exchange programmes to sign our applications. He told us with malicious pleasure that, “Only the crème de la crème goes to CERN – students from Harvard, Oxford or Cambridge. You come from the University of Granada. I cannot believe you even thought of it.” He wouldn’t sign it, so there went our slight chance of working at CERN.</p>
<p>Since then, I promised myself that one day I would go to CERN through the big door and open it up to the ones behind me: young hopeful students.</p>
<p>That promise came to fruition in September 2013 when our group’s proposal to run an experiment at CERN was approved. Our work, which will finally be conducted in November 2016, involves measuring the nuclear shapes of very rare nuclei. Some of our postgraduates have already received training, and did so well that they were awarded a prestigious CERN fellowship.</p>
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<a href="https://images.theconversation.com/files/138236/original/image-20160919-11108-es00iq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/138236/original/image-20160919-11108-es00iq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/138236/original/image-20160919-11108-es00iq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138236/original/image-20160919-11108-es00iq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138236/original/image-20160919-11108-es00iq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138236/original/image-20160919-11108-es00iq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138236/original/image-20160919-11108-es00iq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138236/original/image-20160919-11108-es00iq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">UWC students (bottom from left to right) Kenzo Abrahams, Makabata Mokgolobotho and Craig Mehl. They are with CERN employees, including (back, second from left) Professor Maria Garcia Borge.</span>
<span class="attribution"><span class="source">Supplied</span></span>
</figcaption>
</figure>
<p>This experiment will open the doors of CERN to all African institutions. We walked through first. Now others will be able to follow.</p>
<p><strong>Enrolling more women students, as well as those who are not white and those from poor backgrounds, is a huge imperative for South African universities. Are you getting that right in the Physics department?</strong></p>
<p>One of the Physics and Astronomy Department’s highest priorities is to attract and enthuse South African students. We have strong outreach programmes to achieve this. One that I like very much is when we give talks to high school students; those in Grades 10, 11 and 12 who are close to finishing school. Our staff members and postgraduates present examples of the work we do.</p>
<p>It’s especially amazing when one of our postgraduates returns to their own school. You should have heard the eruption when one postgraduate, Sivuyile Xabanisa, told kids at his Khayelitsha high school that he was studying the oldest stars in the universe – and going to Oxford University as part of his training.</p>
<p>We also invite high school groups to events organised at the university. In 2013 <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/2012/haroche-facts.html">Serge Haroche</a> visited our Science Research Open Day. He was the 2012 Nobel Laureate in Physics. The auditorium practically shook with excitement when he handed over a new microscope to pupils from a high school in Wallacedene, a poor area quite close to UWC.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/-ipl6CLiLnc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Nobel Laureate Serge Haroche visits the University of the Western Cape.</span></figcaption>
</figure>
<p>Another really valuable initiative has been the MaNus/MatSci programme for Nuclear Science and Material Science. In the same way that the SKA is driving strong growth in astronomy, this Honours and Masters programme is attracting growing numbers of future nuclear physicists. It trains about 25 South African students each year, most of them black and from poor backgrounds. These students are drawn from historically disadvantaged institutions like the universities of Fort Hare, Venda, Limpopo and the North West – and from UWC’s undergraduate programmes.</p>
<p>All of this work and outreach has produced impressive results. Today there are more than 100 postgraduate students in the Physics and Astronomy Department. Most of them are black South Africans from historically disadvantaged backgrounds. </p>
<p><strong>What are the lessons other African institutions’ science faculties and individual departments can learn from UWC’s recent successes?</strong></p>
<p>We need to break history to change things dramatically. And we must do it the South African, or African way – using our own strengths and methods, not adopting European approaches.</p>
<p>Universities need to work harder to make sure women and all races are equally represented in their science classrooms. At UWC we’ve got a number of postgraduate women students who are doing great science, winning awards and raising the bar for everyone. Having women there makes other women realise the door is open for them. In the same way, having postgraduates like Sivuyile Xabanisa visiting schools in poorer communities makes pupils realise they also have a place in science labs. Role models are so important.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/138237/original/image-20160919-11090-sfbdlu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/138237/original/image-20160919-11090-sfbdlu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/138237/original/image-20160919-11090-sfbdlu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138237/original/image-20160919-11090-sfbdlu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138237/original/image-20160919-11090-sfbdlu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138237/original/image-20160919-11090-sfbdlu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138237/original/image-20160919-11090-sfbdlu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138237/original/image-20160919-11090-sfbdlu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">UWC’s Dr Nico Orce with pupils from Khayelitsha’s Zola High School.</span>
<span class="attribution"><span class="source">Supplied</span></span>
</figcaption>
</figure>
<p>Ultimately, UWC wants to be number one for physical science not just in Africa but in the world. To do that, we cannot constantly fight among ourselves as individual researchers or with other institutions on the continent. The only competition we need is the healthy sort that improves everyone’s performance. </p>
<p>Collaboration is really crucial. UWC applied for about R30 million from country’s the National Research Foundation and its Department of Science and Technology to build a new detector system called <a href="https://www.uwc.ac.za/Faculties/NS/NuclearPhysics/Pages/Gamka.aspx">GAMKA</a>.</p>
<p>The construction will happen at iThemba LABS in Cape Town and involves a consortium of both wealthy and less well resourced universities. We’ll all have to work closely together, with the same aim, to be successful. That’s the key to making African science soar: knowing that if you try to do it alone, you won’t have all the skills or equipment. Together we can lead science worldwide through work done right here on the continent.</p><img src="https://counter.theconversation.com/content/65284/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nico Orce receives funding from the National Research Foundation (NRF), the South African-CERN Collaboration (Department of Science and Technology) and the University of the Western Cape.</span></em></p>Collaboration is one of the keys to making African science soar: when the continent’s universities work together, they can produce amazing results.Nico Orce, Associate Professor in the Department of Nuclear Physics and Nuclear Astrophysics, University of the Western CapeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/490252015-10-15T04:13:25Z2015-10-15T04:13:25ZBenefits of knowing more about neutrinos which pass through our bodies unnoticed<figure><img src="https://images.theconversation.com/files/98365/original/image-20151014-12654-1q4usks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Neutrinos, we're looking for you! Japan's Super-Kamiokande detector.</span> <span class="attribution"><span class="source">Kamioka Observatory, ICRR (Institute for Cosmic Ray Research), The University of Tokyo</span></span></figcaption></figure><p>The observation that <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2015/">neutrinos</a> have mass, which led to the 2015 Nobel Prize for Physics being awarded jointly to Japan’s Takaaki Kajita Japan and Canada’s Arthur McDonald, is important for two key reasons. First, it provides a deeper knowledge of the fundamental tenets of nature. Second, as with any discovery, it comes with innovation in science and technology. </p>
<p>While we know of the existence of neutrinos, not much is known about them. Neutrinos exist in huge numbers in the universe. That is why understanding neutrinos is directly relevant to our knowledge of the universe. </p>
<p>Now that it has been established that neutrinos have <a href="http://www.sciencedaily.com/releases/2015/10/151006083633.htm">mass</a>, we have a key to better understanding how mass is distributed in the universe. Neutrinos may also contribute to understanding why the universe is continuously expanding. </p>
<p>It sits on the similar scale as the discovery of the <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2013/">Higgs boson</a> at the <a href="http://home.web.cern.ch/topics/large-hadron-collider">Large Hadron Collider</a> at European Organisation for Nuclear Research (<a href="http://home.web.cern.ch/about">CERN</a>), and the future discoveries expected from the <a href="http://www.ska.ac.za/about/project.php">Square Kilometre Array</a> (SKA) project. </p>
<p>Any discovery in experimental science is the result of titanic efforts to overcome technological difficulties and challenges. When the neutrino was first <a href="http://www.pbs.org/wnet/hawking/strange/html/neutrinos.html">postulated</a> in 1930, many thought that it would be mission impossible to detect them, let alone to study its properties – such as its mass.</p>
<p>The relentless need to understand nature better forces scientists to innovate with which to push the boundaries of science and technology. The efforts exerted to demonstrate that neutrinos contain mass have bolstered science and technology in <a href="http://www.cbc.ca/news/technology/canadian-s-nobel-prize-in-physics-highlights-why-basic-science-matters-1.3262835">Canada</a> and <a href="http://www.gmanetwork.com/news/lite/story/539768">Japan</a>. South Africa’s <a href="http://mg.co.za/article/2013-11-27-sa-will-feel-economic-benefits-of-ska-says-director-general">support</a> of projects at CERN, the SKA and other efforts already have a similar effect.</p>
<p>Boosting science and technology via large scientific projects brings the added value of human capacity development in high technology that South Africa is in so much need of.</p>
<h2>What are neutrinos?</h2>
<p>Before answering this question we need to backtrack a bit. Matter is made of <a href="http://education.jlab.org/atomtour/">atoms</a>. Atoms are made of positively charged <a href="http://dictionary.reference.com/browse/nuclei">nuclei</a> and negatively charged <a href="http://dictionary.reference.com/browse/electron">electrons</a> travelling very fast around the nuclei. </p>
<p>The electro-magnetic force holds the electrons in orbit around the nuclei because opposite electric charges attract each other. Nuclei are very heavy compared to electrons and are composed of protons and neutrons. </p>
<p>Neutrinos can be thought of cousins of the electrons, only neutral. Neutrinos share some of the properties of the electrons – for instance, the spin. There is one type of neutrino coupled to the electron, which is called electron neutrino. The electron has an anti-particle, the positron, which has positive electric charge. There is also an electron anti-neutrino.</p>
<p>In nature there are other charged particles that are similar to the electron, which are called muons and taus. These are heavier than the electron. The muons and taus also have two other types of neutrinos respectively. In total we are aware of three types of neutrinos (electron, muon, and tau) and their anti-particles.</p>
<h2>Why are neutrinos elusive?</h2>
<p>Neutrinos do not have electric charge. Therefore, they do not get repelled or attracted to other charged particles in nature. They interact very weakly with matter so they very rarely leave a trace. </p>
<p>Vast amounts of neutrinos <a href="http://timeblimp.com/?page_id=1033">pass through us</a> every day, but we do not feel them because neutrinos hardly ever interact with the atoms that make up our bodies.</p>
<p>Most of the neutrinos that pass through earth come from the sun and are produced by nuclear fusion. These are called solar neutrinos. The other neutrinos are produced as a result of the collision of cosmic particles with the Earth’s atmosphere. These are called atmospheric neutrinos.</p>
<h2>How can we tell that neutrinos have mass?</h2>
<p>There are three types of neutrinos. If neutrinos were massless then they would travel forever unencumbered. If neutrinos have mass then, as they travel, they gradually “disappear” to become a different type of neutrino. </p>
<p>This is referred to as neutrino oscillation and it is a quantum mechanical effect. </p>
<p>For instance, the Sun creates electron neutrinos. By the time neutrinos reach Earth we only observe about one-third of the emitted neutrinos. The remaining two-thirds of the electron neutrinos becomes muon and tau neutrinos. Through this process, it is directly demonstrated that neutrinos have mass.</p>
<h2>Decades of research pay off</h2>
<p>Neutrinos were put forward in 1930 as a means to explain missing energy from a certain type of nuclear reactions. It was not until 1956 that neutrinos were detected unequivocally in laboratory conditions, for which a <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/1995/press.html">Nobel Prize in Physics</a> was awarded in 1995. </p>
<p>Scientists from all over the world have not stopped investigating the nature of these elusive particles. Neutrinos were known to be neutral and assumed to be massless. It was not until the late 1990s and early 2000s that experimental techniques became available in order to elucidate if neutrinos have mass. </p>
<p>The latter signifies a major discovery in physics, leading to a Nobel Prize in Physics in 2015. The fact of the matter is that to date we do not really know how neutrinos acquire mass. Unravelling this mystery may lead to other groundbreaking discoveries.</p><img src="https://counter.theconversation.com/content/49025/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bruce Mellado receives funding from the DST, the NRF, Wits research office.</span></em></p>The Nobel Prize-winning research on neutrinos is expected to push the boundaries of science and technology.Bruce Mellado, Professor of Physics, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.