SKA will be the biggest radio telescope ever built

This is one of the biggest and most ambitious scientific tools of the XXIst century. The Square Kilometre Array, or SKA, is an impressive radio telescope project, which will build an array of 130 15m-diameter dish antennas in South Africa and an array of 130’000 TV-like antennas in Western Australia in the coming years. Thanks to it, some of the Universe’s greatest mysteries will be studied with a whole new level of precision. Along with thirteen countries officially involved, Switzerland is considering participating in this huge adventure. As an initial step, EPFL was just granted special member status of the SKA Organisation (SKAO) and will be the lead institution coordinating the contributions to the SKA on behalf of the Swiss academic community, which also integrates the University of Geneva.

Most telescopes we readily think of use optical light similar to what we see with our eyes. The SKA will capture light of celestial objects at radio waves, similar to the light used by our smartphones to communicate together. At radio waves, the sky is much different that the one we see in optical light.

“This new high-performance radio telescope will open a new view of the whole Universe. ” commented Prof. Jean-Paul Kneib of EPFL leading the consortium of Swiss Scientists interested in the SKA project, “SKA will detect the formation of planetary system around distant stars, the cold Hydrogen gas around galaxies, the nuclei of distant galaxies harbouring an active super-massive blackholes”.

“SKA will also measure the magnetic field in galaxies and at larger scales and map the fluctuation of the Hydrogen distribution in the first billion year of the beginning of the Universe” added Daniel Schaerer, Professor at the Department of Astronomy of the Faculty of Sciences of the University of Geneva. “SKA will allow us to address some key questions on our Universe, such as the nature of the Dark Matter and the Dark Energy, or explore the Cosmic Dawn the period of time when the first stars and first galaxies formed”.

As outlined in the white paper Swiss Interests and Contribution to the SKA, published end of February 2020, Swiss scientific institutions(*) and high-tech industry partners are extensively involved in SKA-related science and technology, contributing in research and development in the fields of distributed radio frequency systems, high performance computing, machine learning and artificial intelligence.

Implication of the Theoretical Physics Department (DPT)

The Physics Section is interested in a wide range of science topics that are enabled by the SKA thanks to the unprecedented size and depth of its surveys" says Prof. Martin Kunz. In particular, researchers at the DPT are involved in research related to the surveying transient multi-messenger sources (which are detectable in electromagnetic and gravitational-wave observations), the origin and evolution of magnetic fields in the Universe and their effects on the formation of structures. "The SKA will enable us to answer fundamental physics questions by its ability to probe the Epoch of Reionization, which represents the last major transition of the ordinary matter in the Universe after the Big Bang", comments Dr Hamsa Padmanabhan, a scientific collaborator with the Ambizione grant.

Scheme summarizing the interests of the Theoretical Physics Department in the SKA project.

Of particular interest are also the prospects for unravelling the nature of dark energy, the unknown major component of the Universe that behaves like a fluid having negative pressure, and of dark matter, which makes up about 25% of the Universe's content but has hitherto not been found in the laboratory. "The ability of the SKA to map the evolution of structures at the largest scales will also allow us to design new tests of Einstein's general theory of relativity" comments Prof. Camille Bonvin. Such tests will also benefit from the detection from the SKA of low-frequency gravitational waves from the merging of supermassive black holes.