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What’s happening just outside a black hole? Neil deGrasse Tyson and cohost Gary O’Reilly travel to Oxford University to explore the mysterious universe of black holes, their accretion disks, and the impact they have on the world around them with astrophysicist Steve Balbus and theoretical physicist Andy Mummery.

We uncover the transformation of black holes from speculative phenomena to wellaccepted cosmic entities. Discover how black holes are formed, a question that puzzled scientists until the 1990s, and how Balbus and John Hawley's pioneering work revealed the crucial role of magnetic fields and turbulence in accretion discs. Dive into the MagnetoRotational Instability (MRI) theory, a breakthrough that explains the turbulent behavior of gas around black holes. Learn about the visualization of turbulence through computer simulations, showing how even weak magnetic fields can destabilize gas.

We also explore Kerr black holes, named after Roy Kerr, and their rotating nature. Unravel the unsolved problems from Einstein’s work, especially regarding orbits close to the singularity where relativistic effects dominate. Andy discusses the challenges in calculating these orbits and provides fresh insights into black holes’ impact on their environment.

Why can’t objects orbit just above the event horizon? Understand the balance of forces and why closer proximity leads to catastrophic instability. Explore the origins of our black hole data, primarily from Xray telescopes, and the impending loss of critical instruments like the Chandra Xray Observatory.

Finally, hear Andy’s take on the biggest unanswered questions: the spin rates of black holes, their formation, and evolution over cosmic timescales. From the flaying of stars to the intense gravitational interactions, we explore these great enigmatic giants of our universe.

Timestamps:
00:00 Introduction: Steve Balbus
1:38 Theorizing Black Holes & Magneto Rotational Instability
9:25 General Relativity & Books
14:35 Solving Einstein’s Equations & Kerr Black Holes
18:22 Orbits Around Black Holes
24:13 How Close Can You Orbit a Black Hole?
28:18 Why Can’t You Orbit Right Above a Black Hole?
34:00 Why Interstellar’s Gargantuan is Wrong?
36:19 Black Hole XRays
39:42 Current Unsolved Problems
44:06 A Cosmic Perspective

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Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic cohosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!

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