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Manchurian Taikonaut
2004-Jul-15, 12:44 PM
He's about to annouce a big new idea ?

the Cosmologist Stephen Hawking has claimed a breakthrough in black-hole research


did anyone hear anymore on this , and what is going to happen ?

kucharek
2004-Jul-15, 12:54 PM
Perhaps http://www.nature.com/news/2004/040712/full/040712-12.html

CTM VT 2K
2004-Jul-15, 02:21 PM
Is he saying that Black Holes evaporate?

SiriMurthy
2004-Jul-15, 02:21 PM
Here's another link:
http://www.reuters.co.uk/newsArticle.jhtml?type=scienceNews&storyID=5679660 &section=news

I am quoting from this article (emphasis mine):

....In the 1970s, Hawking said that once a black hole formed it lost mass by radiating energy, known as "Hawking radiation," but it contained no information about the inside matter and once the hole evaporated, all information was lost.....

....He will now argue that the black holes never quite shut themselves off completely and, as they emit more heat, they eventually open up and release information.....

My question is: what is this information they are talking about?

SiriMurthy
2004-Jul-15, 02:22 PM
Is he saying that Black Holes evaporate?

Yup. Eventually.

kucharek
2004-Jul-15, 02:34 PM
Is he saying that Black Holes evaporate?

Yup. Eventually.

I think, this is some part of his theory that is accepted since a long time. Somewhat the event horizon meets the Heisenberg uncertainty principle.

Disinfo Agent
2004-Jul-15, 03:27 PM
New Scientist article (http://www.newscientist.com/news/news.jsp?id=ns99996151)


Hawking cracks black hole paradox


After nearly 30 years of arguing that a black hole destroys everything that falls into it, Stephen Hawking is saying he was wrong. It seems that black holes may after all allow information within them to escape. Hawking will present his latest finding at a conference in Ireland next week.

The about-turn might cost Hawking, a physicist at the University of Cambridge, an encyclopaedia because of a bet he made in 1997. More importantly, it might solve one of the long-standing puzzles in modern physics, known as the black hole information paradox.

Argos
2004-Jul-15, 03:38 PM
According to the Hawkings proposal (already splitting the academic community), the information previously swallowed by the black hole would be released in an outburst, at the final moments of a black holes life. Since black holes live a long time I suppose it will be difficult to observe this final burst in nature to confirm the theory; theres no BH decaying around. Large BHs will take billions of years to decay.

(*) Instruments like the Large Hadron Collider could be able to test the hypothesis of information recovery, by generating tiny short-life black holes and observing their decay. Im not sure on this.

Btw, without singularities our beautiful wormhole galaxywide transport system is a wreck! There goes another paradigm... :cry:

Brady Yoon
2004-Jul-15, 05:39 PM
Small black holes should be exploding right about now, if the Hawking theory is correct. Could they be gamma ray bursts?

Swift
2004-Jul-15, 07:29 PM
My question is: what is this information they are talking about?
Since no one has answered, I'll take a crack, but this is all IIRC and IMHO...
From the outside, there is only certain information you can obtain about a black hole: its mass, its spin (angular momentum), and if it has an electrical charge. An atomic particle about to fall into a black hole may have other properties (nuclear spin state, what quarks it is made of, etc.) When the particle disappears into the event horizon, all that information (properties) is lost. You can not even tell the sum of all that information from all the particles from the outside. I think that is the information they were talking about.

I thought that only mini-black holes could evaporate, that above a certain size they were stable. Is the new idea that all black holes evaporate and that big ones just take longer; or is that old news and the new idea is that the information is released when they do evaporate?

Argos
2004-Jul-15, 08:04 PM
The big news is that Hawking finally got rid of the singularities. If singularities dont exist, then the information is not crunched ad infinitum and destroyed.


or is that old news and the new idea is that the information is released when they do evaporate?

As I understand it the Hawking radiation will exhaust the black hole so that it shrinks along time. At a certain point, when the shrinking process is almost complete, and the black hole is very small, the information outburst begins, as a radiation flow. For common Black holes this process might take forever, as far as human race is concerned.

John Dlugosz
2004-Jul-15, 08:08 PM
I thought that only mini-black holes could evaporate, that above a certain size they were stable. Is the new idea that all black holes evaporate and that big ones just take longer; or is that old news and the new idea is that the information is released when they do evaporate?

The smaller the BH, the faster it evaporates. A large one will shrink slowly and become a small one. However, a large BH has no trouble sweeping up more dust and gas even in the interstellar vacuum, more than making up for the loss. A BH ejected out of the galaxy would start to shrink.

Disinfo Agent
2004-Jul-15, 08:13 PM
Vveeeeeeeeeeerrrrrrrrrryyyyyyyyyy slowly. :)

Jim
2004-Jul-16, 03:23 AM
The information is C-P-T (charge, parity, time) which Quantum Theory says must be mainatined. Hawking initially said this information was irretrievably lost in the black hole, a major violation of QM which he explained by saying massive gravity destroyed QM.

Here's an interesting page on the subject in which Hawking explains his (now withdrawn) view and Roger Penrose takes the opposing view (which Hawking may now accept):
http://www.fortunecity.com/emachines/e11/86/space.html

Morrolan
2004-Jul-16, 03:57 AM
so does this evaporation mean that at a certain point a BH will stop being a BH and become... what? just a lump of matter?

Normandy6644
2004-Jul-16, 04:09 AM
so does this evaporation mean that at a certain point a BH will stop being a BH and become... what? just a lump of matter?

It will all be radiated away as energy. No matter left.

Duane
2004-Jul-16, 04:34 AM
Actually, I belive Hawking suggested that once a BH radiated away enough mass, it would re-appear as a sudden explosive event, akin to a supernova.

He was discussing mini-black holes when he said this. He once postulated that mini-BHs may have formed at the time of the big bang, although he later decided this wouldn't occur. Regardless, it seems that the mass left in a BH may reappear--although a 30 Solar-mass BH would take something like 10^73 years to reach that point.

Morrolan
2004-Jul-16, 07:12 AM
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.

you'd wonder how all that information is 'stored' inside something like a black hole. the amounts of mass sucked in must be huge (over and on top of the original star mass to begin with).
just a weird thought: maybe there are quantum oceans in BHs with currents and all that in which the information slowly churns around and when it comes to the rim of the BH some parts radiate out.... :o

Argos
2004-Jul-16, 12:15 PM
so does this evaporation mean that at a certain point a BH will stop being a BH and become... what? just a lump of matter?

As I understand it, the final burst will occur in the moment when the density of energy of the vanishing black hole is not enough to sustain an event horizon anymore. Thus, all the energy that was stored in the near-singularity region is released.

I suppose, and this is almost a question, that the first emissions of this radiation would be red-shifted by the high density, which, although not enough to keep an event horizon is enough to impose a considerable warp to the space-time. More energetic emissions would arise as the decreasing energy density allowed for an increasingly weaker gravitational field, and consequently smaller red-shifts. In other words, we should detect such emission in a crescendo, or fade-in, from radio to gamma-ray and then a fade-out as the shockwave of the burst expands. I would also expect some matter to form as the temperature falls.

Manchurian Taikonaut
2004-Jul-16, 09:26 PM
it sounds very good

Joe87
2004-Jul-17, 12:51 AM
"What're quantum mechanics?"


Here is the definitive quantum mechanics (http://www.amazon.com/exec/obidos/ASIN/0837603412/professimechanic/104-5461805-2333551) textbook.

01101001
2004-Jul-17, 07:22 PM
What do you suppose is the minimum number of bits of information a black hole could hold?

Maximum?

(Price range? I'm thinking of getting one for my PC.)

Gullible Jones
2004-Jul-17, 08:25 PM
More than the number of cells in your body.

More than the number of stars in the universe.

More than enough to store the combined memories of the entire world's human population.

More than the capacity of all the hard drives on this planet.

(I'm thinking average. Minimum could be pretty darned small, though such a black hole would last an insanely short amount of time; maximum would be so huge as to be utterly unimaginable.)

Morrolan
2004-Jul-18, 02:57 AM
"What're quantum mechanics?"


Here is the definitive quantum mechanics (http://www.amazon.com/exec/obidos/ASIN/0837603412/professimechanic/104-5461805-2333551) textbook.

:lol: :lol:

SiriMurthy
2004-Jul-18, 10:05 PM
My question is: what is this information they are talking about?
Since no one has answered, I'll take a crack....

Swift, thanks for taking time to answer my question. After I read your response to your question, I reread the original article keeping in mind what this "information" means and all I can say is:

:-k #-o ](*,)

Manchurian Taikonaut
2004-Jul-21, 01:06 PM
I think he might be announcing the newest theory right at this time

01101001
2004-Jul-21, 05:47 PM
I think he might be announcing the newest theory right at this time
Hawking reveals new theory in Dublin (http://212.2.162.45/news/story.asp?j=111593184&p=yyy59389x&n=111593944)


Hawkings answer is that the black holes hold their contents for eons but themselves eventually deteriorate and die. As the black hole disintegrates, they send their transformed contents back out into the infinite universal horizons from whence they came.

There is no baby universe branching off, as I once thought. The information remains firmly in our universe, Hawking said in a copy of his speech distributed just before he appeared at the conference.

Im sorry to disappoint science fiction fans, but if information is preserved, there is no possibility of using black holes to travel to other universes, he said.

Argos
2004-Jul-21, 05:58 PM
Im sorry to disappoint science fiction fans, but if information is preserved, there is no possibility of using black holes to travel to other universes.

I think this also rules out wormhole travel within the universe.

Jerry
2004-Jul-22, 04:43 AM
it sounds very good
Yes, I agree, it sounds a lot better than when I say it...

Does this discussion belong here, or in the against the mainstream topic?

milli360
2004-Jul-22, 01:19 PM
Jerry Jensen:
Does this discussion belong here, or in the against the mainstream topic?
Good question. I'd say it belongs here. It's not a discussion about a theory that goes against the mainstream, per se, like an anti-relativity or anti-big-bang or geocentric theory might. Stephen Hawking almost defines "mainstream." And it is a current event in cosmology, and it is a "nagging question," both of which are mentioned in the purview of General Astronomy.

Normandy6644
2004-Jul-22, 03:55 PM
Jerry Jensen:
Does this discussion belong here, or in the against the mainstream topic?
Good question. I'd say it belongs here. It's not a discussion about a theory that goes against the mainstream, per se, like an anti-relativity or anti-big-bang or geocentric theory might. Stephen Hawking almost defines "mainstream." And it is a current event in cosmology, and it is a "nagging question," both of which are mentioned in the purview of General Astronomy.

I agree. I think it's more mainstream especially since he is saying that the QM paradox is gone. So that's good. :D

JohnD
2004-Jul-22, 09:47 PM
All,
A transcript of Hawking's talk is available here: http://pancake.uchicago.edu/%7Ecarroll/hawkingdublin.txt

Unfortunately for me, he speaks Math and I don't, but I enjoyed wading through the piece for the wry Hawking remarks now and then. (See "science fiction fans").

However, I am comforted by the chatter on Physics Forums @ http://physicsforums.com/showthread.php?t=33532
where physicists who are there in Dublin seem as non-plussed as I am, though expressing their puzzlement in much more educated words. However, when I found what looked like an understandable exposition ( http://golem.ph.utexas.edu/string/archives/000403.html ), I was quickly slapped down by reading, "Ah, now I get it, the idea is that the contribution from the nontrivial topologies completely factors to a constant and can be devided out."

Sorry, Swift, I don't see how the nature of matter going in can be represented by random radiation coming out. Hawking explained his radiation as singletons from virtual pairs of particles in the quantum soup, whose partner had been swallowed by the event horizon. As they are generated by Quantum Uncertainty, the particles must be random. Even if they were not, in what way can such radiation 'inform' us about what went in?
And as Hawking said yesterday, " If you jump into a black hole, your mass energy will be returned to our universe, but in a mangled form, which contains the information about what you were like, but in an unrecognisable state." If it is unrecognisable, how is it 'information'?

I suspect that the physicists are using 'information' in a different way to the rest of us. All the articles I can find print it that way, in single quotes, as if it was a special usage.
Oh, well. I'll wait until someone can explain 'information' to me.
John

Jerry
2004-Jul-26, 02:12 AM
All,
A transcript of Hawking's talk is available here: http://pancake.uchicago.edu/%7Ecarroll/hawkingdublin.txt

Unfortunately for me, he speaks Math and I don't, but I enjoyed wading through the piece for the wry Hawking remarks now and then. (See "science fiction fans").


I suspect that the physicists are using 'information' in a different way to the rest of us. All the articles I can find print it that way, in single quotes, as if it was a special usage.
Oh, well. I'll wait until someone can explain 'information' to me.
John
As I read it, consistent with dark energy, Hawking's is stuffing the cosmological constant back into the Einstein-deSitter, but since the constant is much smaller than necessary to maintain a steady state, black holes will still form. Some of the matter sucked into a black hole can ride a wave or saddle and be thrown back out through a black hole torus.

If this is true, we should also see evidence of these inflection points...good grief, could black holes be kicking out quasars? If not, where is the evidence of Hawkings new constraints? The Crab nebula?

Kebsis
2004-Jul-28, 06:36 AM
So is he saying there is no singularity? No point of infinite density?

Then how does a BH stuff so much stuff into such a small volume?

Jerry
2004-Jul-31, 08:20 AM
So is he saying there is no singularity? No point of infinite density?

Then how does a BH stuff so much stuff into such a small volume?
GR's singularity is and always has been speculative, it is just as conceivable, (and to some of us, more probable), that there is indeed a torus formed under great duress and whatever is at the center of galaxies, and it is not in this definition a BH, leaks.

Did Hawking's change his theory because of failing big bang constraints, or because he is aware the jets and stuff spewing out of galactic centers, the apparent winds surrounding quasars - none of this stuff was pedicted near a GR singularity - and the e/p pair formation answer no longer could cut it?