Event Horizon
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An Event Horizon is a 4D spherical region around a black hole beyond which events cannot affect an outside observer.
- See: Dynamical Horizon, Spacetime, Redshift, Proper Time, Absolute Horizon, Apparent Horizon, Cauchy Horizon, Killing Horizon, Photon Sphere, Ergosphere.
References
2015
- (Wikipedia, 2015) ⇒ http://en.wikipedia.org/wiki/event_horizon Retrieved:2015-11-17.
- In general relativity, an event horizon is a boundary in spacetime beyond which events cannot affect an outside observer. In layman's terms, it is defined as "the point of no return", i.e., the point at which the gravitational pull becomes so great as to make escape impossible. An event horizon is most commonly associated with black holes. Light emitted from inside the event horizon can never reach the outside observer. Likewise, any object approaching the horizon from the observer's side appears to slow down and never quite pass through the horizon, with its image becoming more and more redshifted as time elapses. The traveling object, however, experiences no strange effects and does, in fact, pass through the horizon in a finite amount of proper time. From here to the central singularity will take 0.0001 seconds in proper time, in free fall, for a 30 solar mass black hole. This infall time is proportional to the mass of the black hole.[1]
More specific types of horizon include the related but distinct absolute and apparent horizons found around a black hole. Still other distinct notions include the Cauchy and Killing horizon; the photon spheres and ergospheres of the Kerr solution; particle and cosmological horizons relevant to cosmology; and isolated and dynamical horizons important in current black hole research.
- In general relativity, an event horizon is a boundary in spacetime beyond which events cannot affect an outside observer. In layman's terms, it is defined as "the point of no return", i.e., the point at which the gravitational pull becomes so great as to make escape impossible. An event horizon is most commonly associated with black holes. Light emitted from inside the event horizon can never reach the outside observer. Likewise, any object approaching the horizon from the observer's side appears to slow down and never quite pass through the horizon, with its image becoming more and more redshifted as time elapses. The traveling object, however, experiences no strange effects and does, in fact, pass through the horizon in a finite amount of proper time. From here to the central singularity will take 0.0001 seconds in proper time, in free fall, for a 30 solar mass black hole. This infall time is proportional to the mass of the black hole.[1]