steven hawking: i was wrong !!!

Costic/Fallguy/Fullguy lesson !

Steven Hawking: I was wrong

From correspondents in London
July 16, 2004

AFTER almost 30 years of arguing that a black hole swallows up everything that falls into it, astrophysicist Stephen Hawking did a scientific back-flip today.

The world famous author of a Brief History of Time said he and other scientists had got it wrong - the galactic traps may in fact allow information to escape.

"I've been thinking about this problem for the last 30 years, and I think I now have the answer to it," Mr Hawking told the BBC Newsnight program.

"A black hole only appears to form but later opens up and releases information about what fell inside. So we can be sure of the past and predict the future," he said.

The findings, which Mr Hawking is due to present at the 17th International Conference on General Relativity and Gravitation in Dublin on July 21, could help solve the "black hole information paradox", which is a crucial puzzle of modern physics.

Exactly what happens in a black hole - a region in space where matter is compressed to such an extent that not even light can escape from their immense gravitational pull - has long puzzled scientists.

They initially posited theories that the holes were like a cosmic vacuum cleaner, sucking up everything in their path.

Mr Hawking revolutionised the study of the holes when he demonstrated in 1976 that, under the strange rules of quantum physics, black holes are capable of radiating energy.

He calculated that once black holes form they effectively start to "evaporate" away, radiating energy and losing mass in the process.

But by conjuring up the so-called "Hawking radiation", the Cambridge mathematician, who is crippled by motor-neurone disease, also created one of the biggest conundrums in physics.

That conundrum about the fate of what enters a black hole became known as the "information paradox".

According to current theory, Hawking radiation contains no information about the matter inside a black hole, and once the black hole has evaporated, all the information within it is lost.

However this conflicts with a central tenet of quantum physics, which says that such information can never be completely wiped out.

Mr Hawking said that the recapturing the information had important philosophical and practical consequences.

"We can never be sure of the past or predict the future precisely," he said. "A lot of people wanted to believe that information escaped from black holes but they didn't know how it could get out."

Mr Hawking did not elaborate on the BBC program how the information could be extracted from the black hole. Curt Cutler, from the Albert Einstein Institute in Golm, Germany, which is chairing the meeting in Dublin, told New Scientist magazine that Mr Hawking asked at the last minute for permission to address the conference.

"He sent a note saying 'I have solved the black hole information paradox and I want to talk about it'," Mr Cutler said.

If Mr Hawking succeeds in making his case, he will lose a bet that he and theoretical physicist Kip Thorne, of the California Institute of Technology (Caltech) made with John Preskill, also of Caltech.

The terms of the bet were that "information swallowed by a black hole is forever hidden and can never be revealed". Mr Preskill bet against that theory.

The forfeit is an encyclopaedia, from which Mr Preskill can recover information at will.