Schwarzschild radius

E7615

The Schwarzschild radius is the critical distance from the center of a non-rotating, spherically symmetric mass at which its escape velocity equals the speed of light, defining the boundary of a black hole.


Statements (47)
Predicate Object
instanceOf concept in general relativity
length scale
physical quantity
alsoKnownAs gravitational radius
appearsIn Schwarzschild solution to Einstein field equations
appliesTo non-rotating spherically symmetric mass
associatedWith Schwarzschild black hole
assumes non-rotating mass
spherical symmetry
uncharged mass
category black hole physics
relativistic gravitation
contrastsWith Kerr radius for rotating black holes
Reissner–Nordström radius for charged black holes
coordinateSingularityAt Schwarzschild coordinates
definedBy distance from the center of a mass where escape velocity equals the speed of light
defines event horizon of a non-rotating black hole
dependsOn gravitational constant G
mass M
speed of light c
dimension length
discoveredBy Karl Schwarzschild
escapeVelocityAtRadius speed of light
forEarthApprox about 9 millimeters
formulatedInTheory general relativity
forSunApprox about 3 kilometers
generalizationOf Newtonian escape velocity condition
implies inside radius light cannot escape to infinity
marksBoundary region from which nothing can escape
mathematicalExpression r_s = 2GM/c^2
namedAfter Karl Schwarzschild
notEqualTo physical surface of any material object
physicalMeaning radius of event horizon for a non-rotating uncharged black hole
proportionalTo mass of the object
relatedTo Schwarzschild metric
black hole
event horizon
gravitational collapse
scalesLinearlyWith mass of black hole
SIUnit meter
symbol r_g
r_s
usedIn astrophysics
black hole thermodynamics
cosmology
usedToEstimate size of black hole
yearIntroduced 1916


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