|astronomy the surface around a black hole enclosing the space from which electromagnetic radiation cannot escape due to gravitational attraction. For a non-rotating black hole, the radius is proportional to the mass of the black hole|
|event horizon (ĭ-věnt') Pronunciation Key
A spatial boundary around a black hole inside which gravity is strong enough to prevent all matter and radiation from escaping. The inability of even light to escape this region is what gives black holes their name.