Black Hole

Infalling matter

Sharp event horizon

point of no return

Point-like singularity

Hawking radiation consists of random energy

Potential wormholes to other universes

Multiverses

Fuzzball

Infalling matter

No sharp event horizon

Messy surface stores information

in vibrating strings

Hawking radiation carries

information back out

Wormholes may exist

but are unreachable

Evolution theory of black holes

1915

Albert Einstein's general theory of relativity describes how matter and energy bend space-time.

1916

Karl Schwarzschild solves Einstein's equations for the case f a very dense point mass.

1965

Roger Penrose develops the idea of a singularity, a point wheere space becomes infinitely dense.

1967

John Wheeler coins the term "black hole" to describe a star that collapses to a singularity.

1969

Penrose suggests that singularities are hidden behind an event horizon.

1973

Stephen Hawking and Jacob Bekenstein calculate the entropy - a measure of the amount of information - in a black hole and get a very large answer.

1975

Hawking shows quantum mechanics predicts that energy escapes from black holes.  he and colleague Kip Thorne bet John Preskill that this Hawking radiation cannot carry information.

1996

Andrew Strominger and Cumrun Vafa use string theory to calculate the entropy of a black hole, geting the same answer as Hawking and Bekenstein.

2004

Calculations in quantum mechanics and string theory suggest that information can escape from black hles.  Hawking concedes the bet.  Models of black holes from string theory cast doubt on the idea of singularity.

New Scientist 22 January 2005 P.30-33