event horizon


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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 +.
References in periodicals archive ?
Sgr A* (pronounced Sadge A-star) has, if theory is correct, an event horizon about 24 million kilometers in diameter--small enough to fit inside Mercury's orbit of the sun.
Similarly, light leaving the surface of a body undergoing gravitational collapse, at the instant that it passes its event horizon, takes an infinite amount of observer time to reach an observer, however far that observer is from the event horizon.
The experiment, reported in the March 7 Science, showed that the "swimmer" waves were unable to get into the event horizon, rather than unable to escape it.
The event horizon is the gravity field of a black hole where the space-time is so bent that light cannot escape it.
If such pairs come into existence just outside the event horizon, sometimes the negative-energy particle will fall into the hole, while the particle with positive energy will remain out side and eventually escape, Hawking realized.
For the intensity of the X-ray flare to vary so quickly, the event horizon can be no larger than the distance light travels in 10 minutes.
Sean Pertwee projects as Blue Juice, Stiff Upper Lips, Cadfael, Cleopatra, Event Horizon, The 51st State and Dog Soldiers turned him into a heart-throb.
Anything that passes through this event horizon is done for, because the gravitational pull is so great it makes escape impossible.
All that is of interest here is that a model should exist with this geometry in the limit of the Schwarzschild metric, and has an event horizon a quarter the size of general relativity.
On the other hand, probably the intellectually most important application of connections between media and geometries lies in the quantum physics of the event horizon, which, for the first time, could be studied in the laboratory.
CounterTack will preview these new solutions, along with an enhanced version of the Event Horizon platform, at the RSA Conference in San Francisco next week at Booth #845.