Book a RAS A&G Highlights April 2024 Online or In Person Ticket
Continental Break-up Along the East African Rift: New Insights from the Turkana Depression
Dr Rita Kounoudis
Plate tectonic theory describes the evolution of Earth’s rigid outer shell over geological time. However, precisely how continental plates break, or ‘rift’, apart to form new oceans is debated because there are few places on Earth where this process is currently active. One such region is the 3000 km-long East African Rift, where narrow rift valleys cut through the uplifted Ethiopian and Kenyan Plateaus – the highest topographical points on the African continent. This talk will focus on an intriguing and largely unexplored segment of the rift – the Turkana Depression. This region stands out in East Africa due to its unusual breadth, low elevation, and unique history as the host of a previous failed rift system through which the East African Rift subsequently developed. Causes for the Turkana Depression’s subdued topography are debated, with main theories suggesting either a significantly thinned crust instigated by its multiple rifting phases, or instead a lack of buoyant mantle support. The development of rifting in an area marked by a prior phase of rifting is also a topic of ongoing discussion.
To address these questions, we rely on detailed crustal and mantle imaging, facilitated by seismograph networks. These networks detect distant earthquakes, allowing us to analyse seismic waves that traverse the deep Earth geology en-route to the station. In almost four decades of passive seismological research into the East African Rift, the Turkana Depression has marked a notable data gap. In this talk we will discuss recent efforts to deploy a seismograph network in the remote Turkana Depression, and review advances in our understanding of rifting.
Dr Rita Kounoudis is a Postdoctoral Research Assistant in Seismology at the University of Oxford. Her research focuses on understanding the evolution of plate tectonics using a diverse range of seismological techniques to map the structure and dynamics of the Earth’s crust and mantle. She completed her PhD at Imperial College London in 2023 which focused on understanding the processes involved in continental breakup by imaging the subsurface along part of the volcanically and seismically active East African Rift.
Gravitational waves and the origins of black holes
Dr Christopher Berry, Fowler A
Gravitational waves provide a new way to study the cosmos. The first observation of gravitational waves in 2015 was the first discovery of a binary black hole, and the first time that we have found a black hole 30 times the mass of our Sun. Gravitational-wave astronomy has progressed rapidly, and we now have revolutionary insights into the population of black holes. Studying these, we can infer how the progenitor stars lived and died. In this talk, we will review the discoveries made by the global gravitational-wave detector network, and see how these observations are advancing our understanding of stellar evolution
Christopher Berry's research focuses on the origins and properties of black holes and neutron stars; he also has a keen interest in public engagement and informal education. He studied at the University of Cambridge, obtaining his PhD from the Institute of Astronomy. He was a postdoctoral research fellow at the University of Birmingham, where he worked on analysing the first observations of gravitational waves. He moved to the Center for Interdisciplinary Exploration and Research in Astrophysics at Northwestern University where he was the CIERA Board of Visitors Research Professor in 2018, and then moved back to the UK to join the University of Glasgow in 2020, where he is currently a Senior Lecturer in the Institute for Gravitational Research. He has won the International Union of Pure and Applied Physics' Young Scientist Prize in General Relativity & Gravitation and the Royal Astronomical Society's Fowler Award for Early Achievement in Astronomy.
Magnetic fields at the edge of the Milky Way supermassive black hole
Ziri Younsi
With the advent of the Event Horizon Telescope (EHT) we can now image the direct vicinity of black hole event horizons using radio telescopes. In 2019 the first ever image of a black hole, in the heart of the Galaxy M87, was published by the EHT. In 2022, the EHT published the first image of the black hole in the heart of our Milky Way, Sagittarius A*. On March 27th 2024, the EHT went a step further, releasing the first polarised image of Sagittarius A*. In this talk I will review imaging of black holes using the EHT, and discuss how these new polarisation measurements are advancing our understanding of how magnetic fields mediate the interaction between a black hole's gravity and its surrounding material environment
Ziri Younsi's research focuses on testing gravity and fundamental physics, with his work helping to enable interpretation of the first images of supermassive black holes from the Event Horizon Telescope (EHT). He is also an active science communicator. He has studied at Cambridge and UCL, later working as a Humboldt Fellow at the University of Frankfurt, before moving back to the UK to join UCL’s Mullard Space Science Laboratory as a Leverhulme Fellow and subsequently as a Stephen Hawking Fellow. He is a member of the EHT's Science Council and co-leads the consortium's Gravitational Physics Working Group. Since 2014, he has worked within the EHT, developing and performing supercomputer simulations of black holes and horizon-scale black-hole imaging. He is a co-recipient of the National Science Foundation's Diamond Achievement Award, the 2020 Breakthrough Prize for Fundamental Physics, and the Royal Astronomical Society's 2021 Group Achievement Award.
Book a RAS A&G Highlights April 2024 Online or In Person Ticket