jeu. 3 déc. · 00:00

12,00 €

Einstein Telescope: to boldly go where no one has gone before For most of human history, exploring the Universe meant looking at it. Telescopes have allowed us to see ever farther into space, revealing stars, galaxies and some of the most violent events in the cosmos. But not everything in the Universe shines. Black holes, for instance, are by definition dark. To explore this hidden Universe, we need a completely different kind of messenger. Gravitational waves are tiny ripples in space and time, produced when extremely massive objects accelerate and collide. Predicted by Einstein more than a century ago, they were detected directly for the first time in 2015, when two black holes spiralled into one another more than a billion years ago. Their discovery gave us an entirely new way of observing the cosmos. The Einstein Telescope, which will perhaps be built in our country, will take gravitational-wave astronomy much further. Hidden deep underground and using highly sensitive laser interferometry, it will detect much fainter signals than current observatories, allowing us to observe black-hole and neutron-star mergers across a much larger fraction of the Universe and much further back in cosmic history. It may also reveal phenomena that we do not yet know exist. In this talk, theoretical physicist Alexandre Sevrin will introduce gravitational waves, present the Einstein Telescope and the challenges it faces, and end with highlighting the exciting scientific mysteries the Einstein Telescope will elucidate. 5 questions What are gravitational waves and how are they produced? How can we detect distortions of space-time that are incredibly smaller than an atom? What can gravitational waves tell us about black holes that light cannot? Why do we need the Einstein Telescope if gravitational-wave detectors already exist? Could the Einstein Telescope reveal entirely new phenomena — or even challenge our current understanding of gravity and the Universe? Alexandre Sevrin is Professor of Physics at the Vrije Universiteit Brussel (VUB), where he works in theoretical high-energy physics and gravitational-wave physics. His research has ranged from string theory and the fundamental structure of space and time to black holes and gravitational waves. Since 2018, he has been actively involved in the development of the Einstein Telescope, the proposed third-generation gravitational-wave observatory in Europe, as well as ETpathfinder, its research and development facility. He is also a member of the Virgo collaboration, where his interests include the search for the stochastic gravitational-wave background -- the faint gravitational-wave signals that could carry information about processes occurring throughout the history of the Universe. He is currently Chair of the Department of Physics at VUB.