Search results
Results from the WOW.Com Content Network
(Supermassive black holes up to 21 billion (2.1 × 10 10) M ☉ have been detected, such as NGC 4889.) [16] Unlike stellar mass black holes, supermassive black holes have comparatively low average densities. (Note that a (non-rotating) black hole is a spherical region in space that surrounds the singularity at its center; it is not the ...
Gravitational singularities are mainly considered in the context of general relativity, where density would become infinite at the center of a black hole without corrections from quantum mechanics, and within astrophysics and cosmology as the earliest state of the universe during the Big Bang. Physicists have not reached a consensus about what ...
Gravitational time dilation; Gravitational waves; ... source located on the event horizon of a black hole and back ... in terms of two constant length ...
A black hole with the mass of a car would have a diameter of about 10 −24 m and take a nanosecond to evaporate, during which time it would briefly have a luminosity of more than 200 times that of the Sun. Lower-mass black holes are expected to evaporate even faster; for example, a black hole of mass 1 TeV/c 2 would take less than 10 −88 ...
is the standard Riemannian metric of the unit 2-sphere. Note the conventions being used here are the metric signature of ( + − − − ) and the natural units where c = 1 is the dimensionless speed of light, G the gravitational constant, and M is the characteristic mass of the Schwarzschild geometry.
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.
The first [1] is given by = where M BH is the mass of the black hole, σ is the stellar velocity dispersion of the host bulge, and G is the gravitational constant. The second definition [ 2 ] is the radius at which the enclosed mass in stars equals twice M BH , i.e. M ⋆ ( r < r h ) = 2 M BH . {\displaystyle M_{\star }(r<r_{h})=2M_{\text{BH}}.}
In Einstein's theory of general relativity, the Schwarzschild metric (also known as the Schwarzschild solution) is an exact solution to the Einstein field equations that describes the gravitational field outside a spherical mass, on the assumption that the electric charge of the mass, angular momentum of the mass, and universal cosmological constant are all zero.