Alternate Definitions for Black holes

A fantastically compact object, predicted by the theory of general relativity, whose gravity is so powerful that not even light can escape from it. A black hole forms when matter collapses to infinite density, producing a singularity of infinite curvature in the fabric of space-time. Each black hole is surrounded by an event horizon, at which the escape velocity is the speed of light. The Schwarzschild radius for the Sun is about 3 km and for the Earth about 1 cm. There is observational evidence for black holes on a remarkable range of scales in the Universe: stellar black hole, intermediate-mass black hole, primordial black hole, mini black hole, supermassive black hole, Schwarzschild black hole, Kerr black hole.

A fantastically compact object, predicted by the theory of general relativity, whose gravity is so powerful that not even light can escape from it. A black hole forms when matter collapses to infinite density, producing a singularity of infinite curvature in the fabric of space-time. Each black hole is surrounded by an event horizon, at which the escape velocity is the speed of light. The Schwarzschild radius for the Sun is about 3 km and for the Earth about 1 cm. There is observational evidence for black holes on a remarkable range of scales in the Universe: stellar black hole, intermediate-mass black hole, primordial black hole, mini black hole, supermassive black hole, Schwarzschild black hole, Kerr black hole.