Prof Roy Maartens of the University of the Western Cape (UWC) holds a South African Research Chairs Initiative (SARChI) Research Chair. He was also the first NRF A-rated scientist from UWC. Modestly, he says the A-rating award attested to the success of astronomy research at UWC – something that was built up from ‘virtually nothing’.
Prof Maartens, who currently leads the Theoretical Cosmology team at the university, explains that cosmology looks at the biggest picture of the universe. As he points out in Signals, the university’s research magazine, ‘I’m interested in the Universe as a whole: how it began, what it contains (including dark matter and dark energy), and how it evolves. The distribution of galaxies in the Universe contains information about all these questions.’
In the past, cosmologists relied mainly on optical telescopes to map the distribution of galaxies. However, powerful radio telescopes such as South Africa’s MeerKAT and the Square Kilometer Array (SKA), the huge international project currently in development in South Africa and Australia, will greatly contribute to these maps. Indeed, the MeerKAT is already making a difference: Prof Maartens’ SKA Research Chair funds a team of postgraduates and postdocs who work with maps of the distribution of galaxies from the MeerKAT radio telescope combined with other surveys. The massive amount of information contained in these large-scale maps of the universe include a ‘fossil’ record of the properties of the very early Universe and an imprint of the dark energy that forces the Universe to expand faster. ‘These maps allow us to test the foundations of our understanding of the Universe, as well as among others Einstein’s 1915 theory of General Relativity and the large-scale smoothness and isotropy of the Universe.’
Prof Maartens continues: ‘Tiny irregularities were imprinted in the first fraction of a second of the Universe. They grew under the influence of gravity – in some regions, there was a little bit more matter, and because gravity is attractive, it gathers more and more of that matter. Eventually, after many million years, the first stars formed under the force of gravity. Stars attracted each other to form galaxies. Over billions of years, billions of galaxies have formed, with a complex pattern of distribution.’
He adds that, in addition to adding to humankind’s understanding of the origins of the Universe, the skills needed to do the work on galaxy distributions also have other major advantages. ‘The software and data analysis skills the students acquire can also be very relevant outside the research area and are highly valued for data science jobs in industry.’
The journey to becoming a cosmologist
While still a teenager, one of Prof Maartens’ teachers predicted that he could become a scientist. Although nuclear physics sounded exciting at the time, in fact he ‘didn’t have a clue about the different branches of physics. It was only at university that I got a sense of what I wanted to do.’
Today he says he is passionate about the role of mentors in the lives of a new generation of students. He tells how one professor in particular shaped the course of his own career: ‘When I was at UCT, my supervisor was Prof George Ellis who is the founder of cosmology in this country. He’s now in his 80s and still active. He came back to South Africa after getting his PhD at Cambridge University and working overseas. He lectured me during my third year and Honours. I was blown away by how he conveyed his enthusiasm about the cosmos. That set me on the path.’
Prof Maartens’ also tells how that path was not a straight one. In his younger years, most of his energy was consumed by the fight against apartheid. ‘I was a socialist first and foremost, and then an armchair cosmologist. Today it’s the other way round.’
After studying at Oxford University (UK) and holding a position at Wits University – a period during which he was devoted to the struggle against apartheid – he moved again to Britain into a job at Portsmouth University, where he set up a cosmology group that grew to become one of the leading cosmology institutes in Britain. However, he always wanted to return to South Africa and had been visiting Cape Town regularly. ‘When I came to UWC on sabbatical in 2010, they nominated me for the SKA Research Chair. This was my opportunity to return home.’
SKA background and advantages
The MeerKAT radio telescope is a precursor of the SKA (also formally named the Square Kilometre Array Observatory or SKAO). The SKA will look deeper into the Universe and further back in time than any other telescope that probes the distribution of galaxies. It is expected to revolutionise our understanding of the Universe and the laws of fundamental physics. ‘Enabled by cutting-edge technology, it promises to have a major impact on society, in science and beyond,’ says Prof Maartens.
The SKAO is an international undertaking and consists of the SKAO Global Headquarters in the UK, two telescopes at radio-quiet sites in South Africa and Australia, and associated facilities to support the operations of the telescopes. The mission of the SKAO, namely to ‘build and operate cutting-edge radio telescopes to transform our understanding of the Universe, and deliver benefits to society through global collaboration and innovation’ also echoes the approach of NITheCS in terms of collaboration on a global scale.
In a 2012 article in the US journal Science co-authored with his mentor Prof George Ellis (UCT), Prof Maartens said that ‘the success of South Africa’s bid to act as the SKA core site is testimony to the nation’s vision in recognising the potential impact of a high-profile iconic project that is comparable in scope to the Large Hadron Collider in Europe. Hundreds of millions of dollars from the government and a strong astronomy and engineering capability have underpinned the bid.’
Importantly, he says ‘we have been able to fund a large number of students who can become the future of research in South Africa, with the know-how required to take full advantage of the huge scientific infrastructure being developed.’
He adds: ‘After all, the SKA is the world’s biggest astronomy project. It will be there for 50 years at least, and it’s right on our doorstep. It just makes sense to invest in that for the future.’
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