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Hawking cracks black hole paradox

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19 years 9 months ago #3706 by albertw
Hawking cracks black hole paradox was created by albertw
www.newscientist.com/news/news.jsp?id=ns99996151

colleague in work just sent this on to me. Can anyone explain why this is more than the already accepted Hawking Radiation?

Stephen Hawking (Cambridge)

- The information paradox for black holes

The Euclidean path integral over all topologically trivial metrics can be done by time slicing and so is unitary when analytically continued to the Lorentzian. On the other hand, the path integral over all topologically non-trivial metrics is asymptotically independent of the initial state. Thus the total path integral is unitary and information is not lost in the formation and evaporation of black holes. The way the information gets out seems to be that a true event horizon never forms, just an apparent horizon.

ah... clear as mud!

Cheers,
~Al

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/

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19 years 9 months ago #3707 by voyager
Replied by voyager on topic Re: Hawking cracks black hole paradox
WTF, was there actually and ENGLISH in that quoted text!?

No idea if/how that differs from Hawking Radiation.

Bart.

My Home Page - www.bartbusschots.ie

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19 years 9 months ago #3708 by stepryan
Replied by stepryan on topic Re: Hawking cracks black hole paradox

WTF, was there actually and ENGLISH in that quoted text!?

No idea if/how that differs from Hawking Radiation.

Bart.


it does seem a bit like gibberish to me. but i suppose the text is being used to hide his climbdown. from what i can see in the accompanying article on the new scientist website my take on it would be that previously black wholes were assumed to have a defined boundry which stuff disappeared into and was never seen again. they then emitted radiation that hawking assumed had no information about the state of the matter inside, it was a bit like taking a spectrograph and there being no bands in this radiation to tell you there was heluim etc. and it's current state. the radiation i assume was completely uniform and was emitted until eventually the black whole disappeared. what he is saying now is that his assumption is wrong and that the black whole doesn't have a rigid barrier that things disappear behind forever. instead somehow information can leak out in the form of radiation. i assume this has something to do with strings but it doesn't go into how this works. the information is leaked out through the event horizon in the form of radiation which is not completely flat but contains something. the event horizon is not rigid it just appears to be. the hawking radiation contradicted quantum physics but under his new theory it doesn't as information is not destroyed. i hope this helps at least i think this is what he means.
stephen.

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19 years 9 months ago #3709 by albertw
Replied by albertw on topic Re: Hawking cracks black hole paradox

WTF, was there actually and ENGLISH in that quoted text!?


Thats the abstract for his talk :-)

I think it translates to

Stuff can evaporate from a black hole by Hawking Radiation. By looking at said stuff we can work out the corresponding anti-stuff that went into the hole. As with all cosmological theories that disprove something, we have to save the current theory, which we do by renaming the event horizon the apparent event horizon -> you still cant get information from behind the event horizon, so its been renamed so you can :-)


any better? :)

Cheers,
~Al

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/

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19 years 9 months ago #3711 by voyager
Replied by voyager on topic Re: Hawking cracks black hole paradox
Thansk for the info Stephen, that actually makes sense!

Al, I think there is a career for you in decyphering techno babble .... can you work the same mirracles on man pages? :wink:

Bart.

My Home Page - www.bartbusschots.ie

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19 years 9 months ago #3713 by stepryan
Replied by stepryan on topic Re: Hawking cracks black hole paradox

Thansk for the info Stephen, that actually makes sense!

Al, I think there is a career for you in decyphering techno babble .... can you work the same mirracles on man pages? :wink:

Bart.


i didn't know hawking had anything to do with man pages ? ;).
stephen.

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