Hawking Radiation

[Andorfiend]

I'm not well enough versed in the various arcane bits of quantum physics involved with Hawking Radiation to follow the math, but...

Isn't the precise character of a particle emitted by a radiating black hole in part affected by the spin I.E. Angular momentum of the black hole?

Because if so I'm at a loss to follow the whole Susskind-Hawking argument. Surely any particle absorbed by the black hole effects its angular momentum in an unbelievably minute but still computable way that preserves a record of it's mass and motion. And therefore the radiation leaving the black hole also theoretically contain information on the particles that made up the black hole in the sum of it's spin.

On a side note, how would two colliding black hole align their angular momentum? That's got to be a royal bastard. Surely it would produce some whacky gravity waves as the twisted bits of space-time surrounding the merging black holes sorts itself out.

 

[csmyth3025]

...On a side note, how would two colliding black hole align their angular momentum? That's got to be a royal bastard. Surely it would produce some whacky gravity waves as the twisted bits of space-time surrounding the merging black holes sorts itself out.

Physicists are hoping to one day be able to detect some of those "whacky gravity waves" that would result from the merger of two black holes. Right now we don't have the technology to detect them.

Chris

 

[Tom_Garcia]

I'm not well enough versed in the various arcane bits of quantum physics involved with Hawking Radiation to follow the math, but...

Most of us fans of science can't do the math either, but we have every right to question the conclusions wrought by it.

Isn't the precise character of a particle emitted by a radiating black hole in part affected by the spin I.E. Angular momentum of the black hole?

It is my understanding a bh emits nothing but energy. Hawking referred, I think, to the appearance of antiparticles at the edges of a bh from which it could then escape. He thought at first nothing could escape from inside a bh, but later stood corrected that bh emit great quantities of energy at its "poles".

Because if so I'm at a loss to follow the whole Susskind-Hawking argument. Surely any particle absorbed by the black hole effects its angular momentum in an unbelievably minute but still computable way that preserves a record of it's mass and motion. And therefore the radiation leaving the black hole also theoretically contain information on the particles that made up the black hole in the sum of it's spin.

I'm sure you meant to say "...affects its angular momentum...." I would agree with you that any substance forced into a bh must have some effect on its angular momentum and thus, as you say, it would leave notice, however small, that it was there.

On a side note, how would two colliding black hole align their angular momentum? That's got to be a royal bastard. Surely it would produce some whacky gravity waves as the twisted bits of space-time surrounding the merging black holes sorts itself out.

Good question but I'd rather not think about it.

 

[csmyth3025]

Welcome to SDC forums Tom!

Chris

 

[TheAnt]

Hello Anorfiend:

I'm not well enough versed in the various arcane bits of quantum physics involved with Hawking Radiation to follow the math, but...

Isn't the precise character of a particle emitted by a radiating black hole in part affected by the spin I.E. Angular momentum of the black hole?

No, not as I understand it the spin have no direct effect. But the size of the event horizon have. But you might have been thinking on the fact that the event horizon might shrink the faster the black hole rotates. So if that was what you had in mind you're not completely off the mark.

Anyhow, and as a sidenote: The particles is produced in pairs out of vacuum fluctuations near the event horizon, where one falls down into the black hole and the other is boosted away and so conserving energy.
And it is this phenomenon that might have smaller black holes evaporate over time. And why it is thought that small ones from the beginning of the universe will have vanished by now. Some limited search have been made for that burst of energy that is thought to be released when that happen. But no clear signal of that kind have been reported as of yet. But to my knowledge there have been no comprehensive search either. So much to look for in this universe that we even haven't had time to lift a few straws on the top of one really large haystack. (If you accept my my dazed and confused analog - haha!)

Because if so I'm at a loss to follow the whole Susskind-Hawking argument. Surely any particle absorbed by the black hole effects its angular momentum in an unbelievably minute but still computable way that preserves a record of it's mass and motion. And therefore the radiation leaving the black hole also theoretically contain information on the particles that made up the black hole in the sum of it's spin.

You're not the only one at loss on this one my friend. The argument is about that information can be preserved, or will be destroyed. And we simply have no consensus on the matter as of yet, and might not be able to get nothing but good opinions for the foreseeable future. Because we simply cannot go there to pick up one copy of 'alien cookbook no 2, on delicious brownies' popping out of the event horizon. :lol: [/quote]

On a side note, how would two colliding black hole align their angular momentum? That's got to be a royal bastard. Surely it would produce some whacky gravity waves as the twisted bits of space-time surrounding the merging black holes sorts itself out.

Correct, there sure would be such a disturbance in spacetime from such an event that the space time would fluctuate in one really major way, and that's why we do try to detect this kind of event foremost in the gravity wave telescopes that are operation around the world. (They do pool their data btw to weed out spurious signals and avoid false detections.) Now this kind of thing does not happen specially often, in fact we might have to wait several lifetimes. So the second bet is a collision of 2 neutron stars which is something that might just about be powerful enough to detect. That if it happens close enough and in the right manner, read fast and really catastrophic. Yet it will be close to the detection limit of the instruments we have now, just slightly above the threshold.