A black hole is formed by the collapse of massive objects. If the heat and pressure supplied by the fusion of the material within the star is less than the gravitational pull inward, the object may collapse to form a white dwarf, a neutron star, or (if it is massive enough) a black hole.

A black hole is termed "black" because nothing can escape from within it, not even light. Everything that passes through the event horizon is gone from the observable universe.

A black hole is a region where matter collapses to infinite density, and where, as a result, the curvature of spacetime is extreme.

The event horizon defines the boundary of a black hole behind which nothing, not even light, can escape.

Consider an event (a given position at a given time) in spacetime. Now imagine that light rays shoot out in all directions from this event. If none of them can escape to an infinite distance then that event is inside the event horizon. If any can escape, that event is o

Predicted in Einstein's General Theory of Relativity.

The horizon has a very large velocity, moving outward at the speed of light.

the closer you are, the higher the escape velocity.

and spacetime has infinite curvature.

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