Hawking changes his mind about black holes


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jonovate
Hawking changes his mind about black holes

Mark Peplow

Physicist plans to pay up on long-standing bet.

Stephen Hawking has admitted he was wrong.

The eminent physicist Stephen Hawking has conceded that information can escape from black holes after all. The idea has been gaining popularity with physicists for some time, but the fact that Hawking, a pioneer of black-hole theory in the 1970s, has finally accepted it is something of a watershed.

"This will come as a surprise to physicists," says Hawking's Cambridge University colleague Gary Gibbons. "His style of doing science is quite dramatic: he will propose a thesis and defend it to the last, until it is overthrown by better reasoning."

It also means that Hawking loses a long-standing bet with John Preskill, a theoretical physicist at the California Institute of Technology, Pasadena.

Hawking had believed that anything swallowed by a black hole was forever hidden from the outside universe. Preskill bet that the information carried by an object was not destroyed when it plummeted into a collapsed star, and could actually be recovered.

"Stephen has changed his position, and I am expecting him to concede the bet," Preskill says. His prize is to be an encyclopaedia, "from which information can be recovered at will". Hawking says that he will indeed honour the wager.

General approach

Hawking's original view follows Einstein's general theory of relativity, which predicts that, at certain locations in space, matter collapses into an infinitely small and dense point, called a singularity. The theory says that the force of gravity at this point is so great that nothing, not even light itself, can escape, hence the term 'black hole'.

Because the singularity is infinitely small, it cannot possibly have any structure and so there is no way that it can hold information. Any data about particles entering the black hole must be lost forever.

My views have evolved

Stephen Hawking

Cambridge University, UK

The problem is that quantum theory, which describes space and matter on very tiny scales, contradicts this. Quantum theory says any process can be run in reverse, so starting conditions can theoretically be inferred from the end products alone. This implies that a black hole must somehow store information about the items that fell into it.

Quantum evolution

Hawking has always stuck resolutely to the idea that once information goes into a black hole, there is no way out. Until now. When news@nature.com asked about his change of heart, Hawking smiled and wrote: "My views have evolved."

The remarkable about-face is the result of Hawking's attempts to combine quantum theory with general relativity in a powerful new theory of quantum gravity. Hawking is due to present his latest ideas at the 17th International Conference on General Relativity and Gravitation, which runs from 18 July to 23 July in Dublin, Ireland. But he gave a preview of the talk at his department in Cambridge University last month.

He has been using a mathematical technique called the "Euclidean path integral". The technique is extremely complex as it lumps all the possible histories of a system into one equation. First used by quantum physicist Richard Feynman, it has generally been applied to subatomic particles. But Hawking has been working for several years to apply the idea to black holes.

"The view seems to be forming in his mind that there isn't a black hole in the absolute sense, there's just a region where things take a very long time to escape," says Gibbons. This suggests that black holes do not actually narrow to a singularity at all.

The great escape

So an object falling into a black hole is not completely obliterated. Instead, the black hole is altered as it absorbs the object. Although it would certainly be very difficult to retrieve any information about that object, the data are still there, somewhere inside the black hole, Gibbons says.

How could that information ever escape? The answer lies in one of Hawking's greatest discoveries: that black holes slowly evaporate into space by losing particles from the very edge of the gravitational precipice at their rim, called Hawking radiation. The black hole eventually shrinks to a tiny kernel, at which point a growing torrent of radiation begins to leak out, potentially carrying the lost information with it.

But Preskill says that Hawking's new take on quantum gravity rests on shaky mathematical foundations, and is unlikely to be embraced by the physics community. "I am sceptical about whether he has found a fully satisfactory resolution to the problem," he says.

http://www.nature.com/news/2004/040712/full/040712-12.html

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Nexus-

didnt stephen hawking die? how can he change his mind after hes dead?

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jonovate

lol he never died?

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Dross

Neato. I'd like to believe that black holes go into another dimension or something similar. This theory would go along with that I think.

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Xer34
didnt stephen hawking die? how can he change his mind after hes dead?

:huh: Since when was he dead?

lol he never died?

Yeah, that could be it :p

Good stuff btw.

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tigerofsweden

this is too much! theyre tooo smart!

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golazo

good read thanks for info

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WishX

Excellent read! Thank you for posting it. I have my own theories on sub-atomic particles, but I've never applied them to the whole black hole idea. Thought fodder, this. Thanks again!

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Colin-uk

Interesting read, thanks ;)

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adam.sproul

Very interesting read.

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the_snitch

Heh dosent stephen hawking have the keyboard in his hand and speak through text to speech? I hope its not Microsoft Sam doing the talking *shudders*

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tomwarren

Cool read, cheers :yes:

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Hum
didnt stephen hawking die? how can he change his mind after hes dead?

:laugh: Easy -- the mind does not die.

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petroid
Heh dosent stephen hawking have the keyboard in his hand and speak through text to speech? I hope its not Microsoft Sam doing the talking *shudders*

"You have selected Microsoft Sam as the computer's default voice"

Lol.. naw, It's a voice similar to the one used on the Amiga, and the first Mac one. I forget who makes it now.

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AminoSC

Gravity is where its at! According to String theory, Gravitons, the basic component of gravity, can transcend all the dimensions. gravitons move freely in this dimension and and fall right into any other dimension. Gravitons are not confined to this dimension like we are. Interesting huh?

We live in a VERY strange universe when we break everything down to the sub-atomic level.

AminoSC ;)

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GNRambo

I saw it on the news, hes gonig to have a huge conference to explain more, i don;t know the date

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multimediatechy

Very interesting read - very much up-to-date with popular science!

Quantum theory and general relativity are always treated as separate ?worlds? so I was quite intrigued by this ?quantum gravity? theory. However, more research needs to be carried out on his ideas and also string theory because at the sub-atomic level it is all theory, i.e. theoretical physics. I will look forward to hearing more about this theory in the future because nothing pleases me more than new theories etc within the scientific community.

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BOOGMaster
Very interesting read - very much up-to-date with popular science!

Quantum theory and general relativity are always treated as separate ?worlds? so I was quite intrigued by this ?quantum gravity? theory. However, more research needs to be carried out on his ideas and also string theory because at the sub-atomic level it is all theory, i.e. theoretical physics. I will look forward to hearing more about this theory in the future because nothing pleases me more than new theories etc within the scientific community.

Ehh...still contriversial...

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skiiper

ah..... the old unification of quantum mechanics and general relativity. You guys should go watch the Elegant Universe.

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