event horizon

(redirected from Horizon (black hole))
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event horizon

The boundary of a black hole: for a nonrotating black hole it is a spherical ‘surface’ having a radius equal to the Schwarzschild radius for a body of a given mass. The event horizon marks the critical limit where the escape velocity of a collapsing body becomes equal to the speed of light and hence no information can reach an external observer. Calculations predict that a body shrinking within its event horizon – or indeed any body that falls inside the event horizon of another – inevitably contracts to a singularity at the precise center of the black hole.

event horizon

[i′vent hə‚rīz·ən]
(relativity)
The boundary of a region of space-time from which it is not possible to escape to infinity. Symbolized +.