" Black holes were invented by J. Robert Oppenheimer and Hartland Snyder in 1939. Starting from Einstein's theory of general relativity, Oppenheimer and Snyder found solutions of Einstein's equations that described what happens to a massive star when it has exhausted its supplies of nuclear energy. The star collapses gravitationally and disappears from the visible universe, leaving behind only an intense gravitational field to mark its presence. The star remains in a state of permanent free fall, collapsing endlessly inward into the gravitational pit without ever reaching the bottom. This solution of Einstein's equations was profoundly novel. It has had enormous impact on the later development of astrophysics. "

― Freeman Dyson , The Scientist as Rebel