Famous Hawking Black Hole Bet Resolved?

Mick Ohrberg writes "In 1997 the three cosmologists Stephen Hawking, Kip Thorne and John Preskill made a famous bet as to whether information that enters a black hole ceases to exist -- that is, whether the interior of a black hole is changed at all by the characteristics of particles that enter it. It now looks like Stephen Hawking and Kip Thorne may owe John Preskill a set of encyclopedias of his choice, since physicists at Ohio State University 'have derived an extensive set of equations that strongly suggest that the information continues to exist -- bound up in a giant tangle of strings that fills a black hole from its core to its surface.'"

Comments

Hawking radiation

[Space cowboy]

Steven had posited in the 70's that the black holes leak (Hawking radiation), but the paradox is that they radiate a 'black-body' spectrum (entirely thermal radiation) in inverse proportion to their mass (so as they get smaller, the radiation increases). The problem here is that all the information went in, but it's very difficult to infer information from a black-body radiated spectrum (!). Steven therefore thinks that information is lost forever.

The article though is a bit hand-wavy over why the information is preserved in this new theory... (I guess Nth dimensional maths doesn't appeal to the reporter :-). I don't think the fact that the string-theory radius matches the black-hole radius is sufficient to prove the case, though it's an interesting pointer, a curious coincidence if indeed it is such ...

Effectively this is a conjecture - if the strings continue to exist, then they'd have the same size as the black hole appears to have. The throwaway statement " That means a black hole can be traced back to its original conditions, and information survives." seems a bit of a stretch though :-)

Simon

Re:Hawking radiation

[CAlworth1]

IANATP (theoretical physicist), but I think I may be able to shed a bit of light on the last question.

As I understand it, the idea is that the particle and the anti-particle come into being at the same place, moving in different dirrectsion, and the anti-particle is more prone to being pulled in somehow due it its being the opposite of the other mass in the black hole. The particle escapes, generating the black-body radiation, and the anti-particle enters the black whole and collides with a corresponding particle, leaving existance as the original particles came into existance - messed up I know.

If anyone is curious, (stolen from The Universe in a Nutshell by Stephen Hawking, the temp of a black hole is

Temp = (h * c^3)/(8 * pi * k * G * M)

where h is planck's constant, c is the speed of light, G is Newton's gravitational constant, k is Boltzman's costant,T is temp, and M is the mass of the black hole.

Re:Hawking radiation

[ralphclark]

Because the escapeing particle was never in the event horizon to begin with, it can contain no information from within the black hole.

Except that the pair of virtual particles are an entangled pair and if one catches the escaped one and measures its quantum state, one then knows the quantum state of the one that fell in. Catch enough of them and you know about an appreciable fraction of the black hole (in theory!)

Now, how the black hole doesn't gain mass from the anti-particle I'm not quite sure

The energy that was used to create the virtual pair came from the black hole's gravitational field, thus robbing the hole temporarily of mass. For each "virtual" particle that escapes as Hawking radiation, that mass is lost permanently so the mass of the hole goes down, over time. Now remember that this loss can only happen at the event horizon; if the black hole is very large, the tidal force (the gravity gradient) at the event horizon will be weak and thus the rate of particle loss will be very low. For very small black holes the tidal force at the event horizon will be enormous and almost all virtual pairs close to the boundary will separate in this way.

So large black holes will simmer coldly, shrinking only with glacial slowness if at all, and small ones will be hot and shrink very rapidly indeed - finally disappearing altogether in an brief, intense burst of radiation, according to Hawking's theory.

Re:Simple question maybe

[benna]

Why not consult Official String Theory Web site :)

Re:status of string theory

[Anonymous Coward]

Responding as I am taking a string theory course from Prof. Zwiebach here at MIT ...

String theory certainly does predict a number of things that are easily testable ... just not right now. For instance, compactified extra dimensions (as SR includes) introduce additional energy terms to simple quantum problems (i.e. "particle in a box" problems, and SHOs). The problem is that these effects are very large; ergo, the energies necessitated to test these theories are somewhat higher than we can accomplish.

Yes, it's a theory, yes it's kinda off-the-wall and feels a bit contrived, but, studying it, I gotta say that it's pretty if nothing else. It's elegant enough and compelling enough - in terms of what it promises to explain - that it's worth following until it's found to actually be wrong.

A quantum theory of gravity might not be so motivating to you, but if you're a physicist, it's worth trying something wonky to get to it. (Speaking of which, Quantum Loop Gravity - also very wonky - is awesome).

And, as for "quite a few people" finding it too philosophical ... well, quite a few people aren't physicists. *shrugs*