Black holes are one of the most remarkable predictions of Einstein's theory of gravity: so much material is compressed into such a small volume that nothing, not even light, can escape.  In Spring 2019, the world-wide Event Horizon Telescope released the first real picture of gas around a massive black hole and the “shadow” it makes as the gas swirls into the black hole.  Dr. Quataert (University of California, Berkeley) describes how these pioneering observations were made and what they have taught us about black holes.Recorded on Jan. 22, 2020