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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 ...
The entropy of a black hole is given by the well-known Bekenstein–Hawking formula S = k B c 3 A 4 G ℏ {\displaystyle S={\frac {k_{\text{B}}c^{3}A}{4G\hbar }}} where k B {\displaystyle k_{\text{B}}} is the Boltzmann constant , c {\displaystyle c} is the speed of light , G {\displaystyle G} is the Newtonian constant of gravitation and A ...
The Penrose process (also called Penrose mechanism) is theorised by Sir Roger Penrose as a means whereby energy can be extracted from a rotating black hole. [1] [2] [3] The process takes advantage of the ergosphere – a region of spacetime around the black hole dragged by its rotation faster than the speed of light, meaning that from the point of view of an outside observer any matter inside ...
The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across. While this may sound large, this ring is only about 40 microarcseconds across — equivalent to measuring the length of a credit card on the surface of the Moon.
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 ...
Hawking radiation is black body radiation released outside a black hole's event horizon due to quantum effects according to a model developed by Stephen Hawking in 1974. [1] The radiation was not predicted by previous models which assumed that once electromagnetic radiation is inside the event horizon, it cannot escape.
Cygnus X-1, the first solid black-hole candidate, was discovered by the Uhuru X-ray space telescope in 1971. [1] Jeremy Bernstein described it as "one of the great papers in twentieth-century physics." [14] After winning the Nobel Prize in Physics in 2020, Roger Penrose would credit the Oppenheimer–Snyder model as one of his inspirations for ...
Total emitted energy, , of a black body as a function of its temperature, . The upper (black) curve depicts the Stefan–Boltzmann law, M ∘ = σ T 4 {\displaystyle M^{\circ }=\sigma \,T^{4}} . The lower (blue) curve is total energy according to the Wien approximation , M W ∘ = M ∘ / ζ ( 4 ) ≈ 0.924 σ T 4 {\displaystyle M_{W}^{\circ ...