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  2. Hawking radiation - Wikipedia

    en.wikipedia.org/wiki/Hawking_radiation

    Early research into black holes was done by individuals such as Karl Schwarzschild and John Wheeler, who modeled black holes as having zero entropy. [3] [4] A black hole can form when enough matter or energy is compressed into a volume small enough that the escape velocity is greater than the speed of light. Because nothing can travel that fast ...

  3. 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 ...

  4. Penrose process - Wikipedia

    en.wikipedia.org/wiki/Penrose_process

    The maximum amount of energy gain possible for a single particle decay via the original (or classical) Penrose process is 20.7% of its mass in the case of an uncharged black hole (assuming the best case of maximal rotation of the black hole). [5] The energy is taken from the rotation of the black hole, so there is a limit on how much energy one ...

  5. Black-body radiation - Wikipedia

    en.wikipedia.org/wiki/Black-body_radiation

    Hawking radiation is the hypothetical blackbody radiation emitted by black holes, at a temperature that depends on the mass, charge, and spin of the hole. If this prediction is correct, black holes will very gradually shrink and evaporate over time as they lose mass by the emission of photons and other particles. A black body radiates energy at ...

  6. 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 ...

  7. Blandford–Znajek process - Wikipedia

    en.wikipedia.org/wiki/Blandford–Znajek_process

    The Blandford–Znajek process is a mechanism for the extraction of energy from a rotating black hole, [1] [2] introduced by Roger Blandford and Roman Znajek in 1977. [3] This mechanism is the most preferred description of how astrophysical jets are formed around spinning supermassive black holes.

  8. Stefan–Boltzmann law - Wikipedia

    en.wikipedia.org/wiki/Stefan–Boltzmann_law

    Similarly we can calculate the effective temperature of the Earth T ⊕ by equating the energy received from the Sun and the energy radiated by the Earth, under the black-body approximation (Earth's own production of energy being small enough to be negligible).

  9. Ergosphere - Wikipedia

    en.wikipedia.org/wiki/Ergosphere

    A black hole with modest angular momentum has an ergosphere with a shape approximated by an oblate spheroid, while faster spins produce a more pumpkin-shaped ergosphere. The equatorial (maximal) radius of an ergosphere is the Schwarzschild radius, the radius of a non-rotating black hole. The polar (minimal) radius is also the polar (minimal ...