Schwarzchild Radius

Radius of the event horizonThe surface surround the region out of which light itself cannot escape a black hole. No signal or information from within the event horizon can reach the outside universe. Furthermore, nothing can prevent a particle from hitting the singularity in a very short amount of proper time once it has surrounding a non-rotating black holeMaximally gravitationally collapsed object predicted to exist by the theory of general relativity, from which no material object, light or signal of any kind can escape. Many black holes form when a high mass supergiant star explodes in a supernova explosion at the end of its life. A star probably. Its size is given by:

For a one solar mass starSelf-luminous object held together by its own self-gravity. Often refers to those objects which generate energy from nuclear reactions occurring at their cores, but may also be applied to stellar remnants such as neutron stars. this is ~3 km.