Black hole entropy

Assembled from 34 blocks · 2 evidence · 27 related

1. Story
2. The proposal, made by Jacob Bekenstein in the early 1970s and given its coefficient by Hawking's 1974 temperature, that a black hole carries entropy proportional to the area of its horizon rather than to any volume. It resolved an apparent violation of the second law - throw a hot gas into a black hole and the entropy of the universe seems to fall - by giving the hole an entropy of its own that necessarily rises. The numbers are extreme: a solar-mass black hole carries an entropy some twenty orders of magnitude larger than the star that formed it, which is another way of saying that almost all the information about that star has become inaccessible. Because the quantity scales with area and not volume, it is the origin of the holographic principle, the suggestion that the degrees of freedom of a region can be accounted for on its boundary. String theory reproduced the exact coefficient for certain highly symmetric extremal black holes in 1996, which is regarded as a genuine success; the general case is not derived. Not a place on Earth.
3. Knowledge
4. The event horizon
5. Hawking radiation
6. Black hole entropy
7. Jacob Bekenstein
8. Connections
9. The event horizon
10. Jacob Bekenstein
11. Hawking radiation
12. Bekenstein assigns entropy to a black hole
13. Hawking shows that black holes radiate
14. Page states what unitarity requires of the radiation
15. The Page curve is reproduced from within semiclassical gravity
16. The Kerr solution and black hole spin
17. Schwarzschild radius
18. Black hole entropy
19. Schwarzschild solves the field equations for a point mass
20. Oppenheimer and Snyder compute continued gravitational contraction
21. Penrose proves that collapse to a singularity is generic
22. The term "black hole" enters use
23. GW150914 - two black holes merge and the signal reaches Earth
24. Black hole entropy
25. Bekenstein assigns entropy to a black hole
26. Stephen Hawking
27. Black hole entropy
28. The black hole information paradox
29. Hawking shows that black holes radiate
30. Hawking argues that information is destroyed
31. The Page curve is reproduced from within semiclassical gravity
32. Evidence
33. Proposes that a black hole carries entropy proportional to the area of its horizon, in order to preserve the second law of thermodynamics. V55 VERIFICATION BASIS: not consulted in session; no research tool was available. Volume and page are from recall and must be checked.
34. Derives thermal emission from a black hole horizon at a temperature inversely proportional to mass. V55 VERIFICATION BASIS: not consulted in session; no research tool was available. Volume and page are from recall of a canonical citation and must be checked. The fuller treatment appeared in Communications in Mathematical Physics in 1975 and is deliberately not cited by volume here.