images

Black hole - Artwork

by

Ron Miller/Novapix

Reference

a-blh02-00039

Date

2017-01-10

Event horizon is a boundary in spacetime beyond which events cannot affect an outside observer. It is defined as "the point of no return", the point at which the gravitational pull becomes so great as to make escape impossible, even for light. Light emitted from inside the event horizon can never reach the outside observer.