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A rotating black hole is a black hole that possesses angular momentum. In particular, it rotates about one of its axes of symmetry. All celestial objects – planets, stars (Sun), galaxies, black holes – spin. [1][2][3] The boundaries of a Kerr black hole relevant to astrophysics. Note that there are no physical "surfaces" as such.
The Kerr metric or Kerr geometry describes the geometry of empty spacetime around a rotating uncharged axially symmetric black hole with a quasispherical event horizon.The Kerr metric is an exact solution of the Einstein field equations of general relativity; these equations are highly non-linear, which makes exact solutions very difficult to find.
A Schwarzschild black hole is described by the Schwarzschild metric, and cannot be distinguished from any other Schwarzschild black hole except by its mass. The Schwarzschild black hole is characterized by a surrounding spherical boundary, called the event horizon, which is situated at the Schwarzschild radius (), often called the radius of a ...
The Schwarzschild radius or the gravitational radius is a physical parameter in the Schwarzschild solution to Einstein's field equations that corresponds to the radius defining the event horizon of a Schwarzschild black hole. It is a characteristic radius associated with any quantity of mass. The Schwarzschild radius was named after the German ...
Boyer–Lindquist coordinates. In the mathematical description of general relativity, the Boyer–Lindquist coordinates[1] are a generalization of the coordinates used for the metric of a Schwarzschild black hole that can be used to express the metric of a Kerr black hole. The Hamiltonian for particle motion in Kerr spacetime is separable in ...
A generalised Kerr–Schild perturbation has the form =, where is a scalar and is a null vector with respect to the background spacetime. [2] It can be shown that any perturbation of this form will only appear quadratically in the Einstein equations, and only linearly if the condition l a ∇ a l b = ϕ l b {\displaystyle l^{a}\nabla _{a}l_{b ...
The ISCO plays an important role in black hole accretion disks since it marks the inner edge of the disk. The ISCO should not be confused with the Roche limit, the innermost point where a physical object can orbit before tidal forces break it up. The ISCO is concerned with theoretical test particles, not real objects. In general terms, the ISCO ...
Eddington–Finkelstein coordinates. In general relativity, Eddington–Finkelstein coordinates are a pair of coordinate systems for a Schwarzschild geometry (e.g. a spherically symmetric black hole) which are adapted to radial null geodesics. Null geodesics are the worldlines of photons; radial ones are those that are moving directly towards ...