Hard Hard difficulty. Black Holes What is the outer boundary of a rotating black hole's ergosphere called? Answer Static limit Draw the answer
Easy Easy difficulty. Black Holes What boundary around a black hole is the point of no return for light and matter? Answer Event horizon Draw the answer
Intermediate Intermediate difficulty. Black Holes Which astronomer shared the 2020 Nobel Prize for discovering the compact object at the Milky Way's center with Reinhard Genzel? Answer Andrea Ghez Draw the answer
Intermediate Intermediate difficulty. Black Holes In the no-hair theorem, black holes are described by mass, electric charge, and what third quantity? Answer Angular momentum Draw the answer
Intermediate Intermediate difficulty. Black Holes Which mathematician discovered the Kerr metric for rotating black holes in 1963? Answer Roy Kerr Draw the answer
Hard Hard difficulty. Black Holes Which vacuum state models Hawking radiation with no particles incoming from past infinity? Answer Unruh state Draw the answer
Intermediate Intermediate difficulty. Black Holes Which 1939 model describes collapse of a uniform dust sphere into a black hole? Answer Oppenheimer-Snyder model Draw the answer