Decoding the cosmos - with Hiranya Peiris

Unravel the profound mysteries of the universe's explosive birth. Watch the Q&A here (exclusively for our YouTube Channel Members): https://youtu.be/lHh0692c2is Join our channel to get early access, exclusive Q&As, and other perks: https://www.youtube.com/channel/UCYeF244yNGuFefuFKqxIAXw/join This talk was recorded at the Ri on 26 April 2024. Just a century ago, observational evidence established the existence of other galaxies besides our own. Soon afterwards, it was discovered that the Universe is expanding, driving a profound change in our understanding of the cosmos. In 1998, the prevailing cosmological paradigm was again upended by the discovery that the Universe's expansion is accelerating. Since then, the remarkable progress in cosmology, spanning Peiris's research career, has been driven by the close interplay between theory and observations. Observational discoveries have led to a Standard Model of cosmology with ingredients not present in the standard model of particle physics – dark matter, dark energy, and a primordial origin for cosmic structure. The physical nature of these ingredients remains a mystery. The race to unravel this cosmic puzzle is now underway, motivating a new generation of ambitious sky surveys across the electromagnetic spectrum and using new messengers such as gravitational waves. Peiris describes some highlights from her journey through this rapidly changing cosmological landscape in this discourse. She also discusses how laboratory experiments are helping us test new fundamental physics paradigms developed to explain cosmological observations. --- 00:00 Intro 1:30 How do we know about the universe? 7:55 Tracing the light of galaxies 13:00 The Legacy Survey of Space and Time (LSST) 16:53 Mapping dark matter with gravitational lensing 22:30 How do we know how far away galaxies are? 32:03 Using machine learning to explore galaxies 35:50 Detecting dark matter in the lab 46:31 The Universe on a table-top 54:58 Condensed matter experiment and cosmology --- Hiranya Peiris holds the Professorship of Astronomy (1909) at Cambridge, the first woman to do so in the 115-year history of this prestigious chair. As a cosmologist, she delves into cosmic mysteries at the edge of our understanding, reaching back to the very first moments of the Universe after the Big Bang, often treading the path of high risk and high reward. She is noted for interdisciplinary research bridging fundamental physics with astronomical data. Peiris recently contributed to the anthology “The Sky Is For Everyone” and works to reach beyond traditional audiences for public engagement, including through science/art collaborations and live science/music events. Her work has been recognised by awards such as the Max Born Prize of the German Physical Society and the Institute of Physics (2021), the Eddington Medal of the Royal Astronomical Society (2021) and the Breakthrough Prize in Fundamental Physics (2018). --- Discourses are one of the Ri’s oldest and most prestigious series of talks. Since 1825, audiences in the theatre have witnessed countless mind-expanding moments, including the first public liquefaction of air by James Dewar, the announcement of the electron by JJ Thomson and over 100 lectures by Michael Faraday. In more recent times, we have had Nobel laureates, Fields medal winners, scientists, authors and artists – all from the cutting-edge of their field. Discourses are an opportunity for the best and brightest to share their work with the world. Steeped in nearly two centuries of tradition, a Discourse is more than just a lecture. The Discourse lasts exactly an hour, and a bell is rung to mark the beginning and end. To keep the focus on the topic, presenters begin sharply at 7:30pm without introduction and we lock the speaker into a room ten minutes ahead of the start (legend has it that a speaker once tried to escape!). Some of our guests and speakers dress smartly for our Discourse events to add to this sense of occasion. Read more about Discourses here: https://www.rigb.org/explore-science/explore/blog/history-friday-evening-discourse ---- The Ri is on Twitter: http://twitter.com/ri_science and Facebook: http://www.facebook.com/royalinstitution and TikTok: https://www.tiktok.com/@ri_science Listen to the Ri podcast: https://podcasters.spotify.com/pod/show/ri-science-podcast Donate to the RI and help us bring you more lectures: https://www.rigb.org/support-us/donate-ri Our editorial policy: https://www.rigb.org/editing-ri-talks-and-moderating-comments Subscribe for the latest science videos: http://bit.ly/RiNewsletter Product links on this page may be affiliate links which means it won't cost you any extra but we may earn a small commission if you decide to purchase through the link.