Sharp event horizon
point of no return
Hawking radiation consists of random energy
Potential wormholes to other universes
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
Albert Einstein's general theory of relativity describes how matter and energy bend space-time.
Karl Schwarzschild solves Einstein's equations for the case f a very dense point mass.
Roger Penrose develops the idea of a singularity, a point wheere space becomes infinitely dense.
John Wheeler coins the term "black hole" to describe a star that collapses to a singularity.
Penrose suggests that singularities are hidden behind an event horizon.
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.
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.
Andrew Strominger and Cumrun Vafa use string theory to calculate the entropy of a black hole, geting the same answer as Hawking and Bekenstein.
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