an astro-chat with

Professor Don Kurtz

Visiting Professor, School of Mathematics and Physics, University of Lincoln, UK

Friday, 11 February 2022

7:00-8:00 pm

Live online

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Small black holes with masses “only” 5-10 times the mass of the Sun form in supernova explosions at the ends of the short lives of the most massive stars. This is gravity at its most extreme. We cannot see a black holes; no light can escape from them. That’s why they are black. But we can, and do, detect them from their tug on other stars and on gas. That now even allows them to be seen in silhouette with the “Event Horizon Telescope”. Black holes do not “suck” things in. But if you get too close to a small one, its tides will tear you to your constituent particles. Down in the hearts of galaxies small black holes encounter and swallow other stars. Just like the “Blob” from the 1958 film (Steve McQueen’s debut), the more a black hole eats, the bigger it gets. Our own Milky Way has a 5 million solar mass black hole at its core. Other galaxies have black holes up to billions of times the mass of the Sun, producing jets streaming over hundreds of thousands of light years travelling at nearly the speed of light. Cosmic fireworks. Black holes power Quasars and other “Active Galactic Nuclei”. Crashing black holes produce stupendous bursts of gravitational radiation, which finally, in just the last few years, is observed. Far, far into the future, at times vastly greater than the current age of the universe, blackholes will eventually evaporate by “Hawking” radiation. They are not forever. This AstroChat will look into the most energetic events since the Big Bang.

This is our 8th Astro-Chat with our distinguished guest Professor Don Kurtz. The session will include a brief illustrated introduction followed by questions and answers. Members of the public will be able to ask questions in the live-chat. The event is hosted by Professor Andrei Zvelindovsky, Head of the School of Maths & Physics at the University of Lincoln, UK.