Schwarzschild radius


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Schwarzschild radius

The radius of the event horizon of a black hole: a critical radius that must be exceeded by a body if light from its surface is to reach an outside observer. For a body of mass M (but zero angular momentum and zero electric charge), the Schwarzschild radius, R S, is given by
R S = 2GM /c 2
where G is the gravitational constant and c the speed of light. If a body collapses so that its radius becomes less than this critical value, then the escape velocity becomes equal to the speed of light and the object becomes a black hole. The Schwarzschild radius is proportional to the mass of a body. For a star the size of the Sun, the Schwarzschild radius is some three km.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Schwarzschild radius

[′shvärts‚shilt ‚rād·ē·əs]
(relativity)
Conventionally taken to be twice the black hole mass appearing in the general relativistic Schwarzschild solution times the gravitational constant divided by the square of the speed of light; the event horizon in a Schwarzschild solution is at the Schwarzschild radius.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
By using the characteristic length (the black hole Schwarzschild radius) [alpha] and a similar characteristic area [beta] for radiation as in (Sapar, 1964, 2013), defined by
The Schwarzschild radius is the radius of the event horizon.
If you plug in the equation above, you'll find that this black hole has a Schwarzschild radius of about...
The radius of a black hole is computed from the "photon sphere" which is 1.5 times the Schwarzschild radius. The internal potential energy of those 10 million black holes all together is -6.42 x [10.sup.54] joules from (12).
* A black hole's Schwarzschild radius tells how small an object of mass M must be for its surface gravity to be strong enough to trap light.
The "weak" quantum fluctuations (considered in the vicinity of the black hole) were argued to be the microscopic source, which on scales of order of the Schwarzschild radius O([r.sub.S]) accumulates and produces metric fluctuations [2, 3].
A constitutive observation of the respective models is the coincidence between the radius of observable universe and the Schwarzschild radius, supposed to be valid over the whole course of the universe's history.
If the source is completely contained within this region, then Rs is identified with the usual Schwarzschild radius. More generally, condition (4) gives a more rigorous representation of the hoop conjecture [28], which allows for the formation of a black hole in the collision of two masses if their impact parameter b is contained within the Schwarzschild radius.
The equation (4.2) is equivalent to saying that the visible cosmos is defined by the Schwarzschild radius of [M.sub.A].
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In the case when domain wall collapses down to its Schwarzschild radius, the black hole forms.
This conforms to the Newtonian acceleration of a Planck mass from a distance matching its Schwarzschild radius. One may quibble over the best definition of [a.sub.p] but it is apparent that [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].