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  2. Schwarzschild radius - Wikipedia

    en.wikipedia.org/wiki/Schwarzschild_radius

    (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 ...

  3. Schwarzschild metric - Wikipedia

    en.wikipedia.org/wiki/Schwarzschild_metric

    The Schwarzschild solution, taken to be valid for all r > 0, is called a Schwarzschild black hole. It is a perfectly valid solution of the Einstein field equations, although (like other black holes) it has rather bizarre properties. For r < r s the Schwarzschild radial coordinate r becomes timelike and the time coordinate t becomes spacelike. [22]

  4. Black hole thermodynamics - Wikipedia

    en.wikipedia.org/wiki/Black_hole_thermodynamics

    In physics, black hole thermodynamics [1] is the area of study that seeks to reconcile the laws of thermodynamics with the existence of black hole event horizons.As the study of the statistical mechanics of black-body radiation led to the development of the theory of quantum mechanics, the effort to understand the statistical mechanics of black holes has had a deep impact upon the ...

  5. Kerr metric - Wikipedia

    en.wikipedia.org/wiki/Kerr_metric

    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.

  6. Hawking radiation - Wikipedia

    en.wikipedia.org/wiki/Hawking_radiation

    A black hole of one solar mass (M ☉ = 2.0 × 10 30 kg) takes more than 10 67 years to evaporate—much longer than the current age of the universe at 1.4 × 10 10 years. [22] But for a black hole of 10 11 kg, the evaporation time is 2.6 × 10 9 years. This is why some astronomers are searching for signs of exploding primordial black holes.

  7. Eddington–Finkelstein coordinates - Wikipedia

    en.wikipedia.org/wiki/Eddington–Finkelstein...

    The horizon r = 2GM and finite v (the black hole horizon) is different from that with r = 2GM and finite u (the white hole horizon) . The metric in Kruskal–Szekeres coordinates covers all of the extended Schwarzschild spacetime in a single coordinate system. Its chief disadvantage is that in those coordinates the metric depends on both the ...

  8. De Sitter–Schwarzschild metric - Wikipedia

    en.wikipedia.org/wiki/De_Sitter–Schwarzschild...

    For small mass black holes, the two are very different — there is a singularity at the center of the black hole, and there is no singularity past the cosmological horizon. But the Nariai limit considers making the black hole bigger and bigger, until its event horizon has the same area as the cosmological de Sitter horizon.

  9. Reverberation mapping - Wikipedia

    en.wikipedia.org/wiki/Reverberation_mapping

    to the RMS velocity ΔV of gas moving near the black hole in the broad emission-line region, measured from the Doppler broadening of the gaseous emission lines. In this formula, R BLR is the radius of the broad-line region; G is the constant of gravitation ; and f is a poorly known "form factor" that depends on the shape of the BLR.