The no-hair result

Assembled from 20 blocks · 2 evidence · 18 related

1. Story
2. The statement that a stationary black hole in general relativity is completely specified by three numbers - mass, angular momentum and electric charge - and that everything else about whatever formed it is erased. A star has composition, rotation profile, magnetic topology and history; the hole it becomes has, at most, three parameters. The name comes from John Wheeler's remark that black holes have no hair. Astrophysically the charge is negligible, so two numbers remain. The claim is testable: a newly merged black hole rings down through a set of damped oscillations whose frequencies and decay times are fixed by mass and spin alone, so measuring more than one such mode overdetermines the system and tests the theorem directly. It is also the origin of the information problem, because if the exterior really retains nothing of what fell in, and the hole then evaporates, the history appears to be gone. Not a place on Earth.
3. Knowledge
4. The Kerr solution and black hole spin
5. The no-hair result
6. Connections
7. The Kerr solution and black hole spin
8. The black hole information paradox
9. Kerr finds the rotating solution
10. The term "black hole" enters use
11. Hawking argues that information is destroyed
12. GW150914 - two black holes merge and the signal reaches Earth
13. The event horizon
14. The no-hair result
15. Innermost stable circular orbit
16. Kerr finds the rotating solution
17. A mechanism for extracting energy from a spinning black hole
18. Evidence
19. The first direct detection of gravitational waves, from the merger of two black holes on 14 September 2015. V55 VERIFICATION BASIS: not consulted in session; WebFetch to www.ligo.org and every other host was refused by the egress proxy. Volume and article number are from recall of a canonical citation; component masses and distance quoted in this pack are recalled central values with uncertainties omitted.
20. The exact vacuum solution for a rotating mass, which is the geometry that applies to astrophysical black holes. V55 VERIFICATION BASIS: not consulted in session; no research tool was available. Title, volume and page are from recall and must be checked.