Astronomers use 'cosmic echolocation' to map black hole surroundings

Material falling into a black hole casts X-rays out into space—and now astronomers have used the echoes of this radiation to map the dynamic behavior and surroundings of a black hole itself. Most black holes are too small on the sky for us to determine their immediate environment, but we can still explore these mysterious objects by watching how matter behaves as it nears, and falls into, them.
Read more: https://phys.org/news/2020-01-astronomers-cosmic-echolocation-black-hole.html?source=Snapzu