TN: Difficulties in the Cellar (Jan. 17, 2011)

originally posted by Jonathan Loesberg:
I so don't know anything about gravity, relativity, quantum mechanics or anything else in this thread with regard to physics. If it hadn't been for Joe telling Ian to watch out for me, I would have read silently with uncomprehending interest.
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This would be in contrast to your comprehending un-interest in Marie-Rivers. Anyway, I know just enough to sound pretentious. But I am curious about the conservation of energy and matter in black holes.
 
originally posted by Ian Fitzsimmons:
originally posted by Jonathan Loesberg:
I so don't know anything about gravity, relativity, quantum mechanics or anything else in this thread with regard to physics. If it hadn't been for Joe telling Ian to watch out for me, I would have read silently with uncomprehending interest.
Click to expand...

This would be in contrast to your comprehending un-interest in Marie-Rivers. Anyway, I know just enough to sound pretentious. But I am curious about the conservation of energy and matter in black holes.
Click to expand...

Ian,
As I recall, that problem was solved with the proposal that black holes radiate energy outward at the event horizon. That was one of Hawking's seminal contributions and appeared in his Nature paper "Black hole explosions?" in 1974. But I'm just an organic chemist recalling my physics education from long ago, so don't put too much credence on my ramblings.

Mark Lipton
 
originally posted by Ian Fitzsimmons:
your ... un-interest
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While ungainly ("lack of interest" could fill in with its hand in its dinner jacket pocket), this is applaudably better than having said "disinterest." (Shudder.)

W00t, IFitz!
 
originally posted by Jeff Grossman:
Edmunds St John 1995 Syrah "Durrell Vineyard" - awwwf, what a stink, and not much better when tasted, another one to sit in the decanter for a while (and hope that Dressner and/or Bueker are praying for it)
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I'm only praying that my sense of smell recovers enough for me to bother drinking my remaining bottle of '95 ESJ Durrell.
 
originally posted by Sharon Bowman:
originally posted by Ian Fitzsimmons:
your ... un-interest
Click to expand...

While ungainly ("lack of interest" could fill in with its hand in its dinner jacket pocket), this is applaudably better than having said "disinterest." (Shudder.)

W00t, IFitz!
Click to expand...

How about "indifference"?
 
Yes, Mark; they emit hugely powerful x-ray beams, don't they - is that the same? A little knowledge is a dangerous thing. I guess in string theory, any unaccounted for energy can jump down the rabbit hole of one of the microscopic dimensions.

Anyway, thanks.
 
originally posted by Ian Fitzsimmons:
Yes, Mark; they emit hugely powerful x-ray beams, don't they - is that the same? A little knowledge is a dangerous thing. I guess in string theory, any unaccounted for energy can jump down the rabbit hole of one of the microscopic dimensions.

Anyway, thanks.
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They emit electromagnetic radiation across the whole spectrum. Quasars are now believed to be supermassive black holes at the centers of galaxies, and they are characterized not only by radio emission, but also by their superluminosity in the visible light range and by powerful X-ray and even gamma ray emissions.

Mark Lipton
 
originally posted by Jeff Grossman:
Sasha and I cannot bear street elevation for long and find the nearest subway while Jay makes a beeline for a nearby bakery. He isn't finished yet?
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I'm still tasting my way through Lulu's offerings. Their interpretation of a Black & White was faithful in concept but incredibly light and airy. One of the most successful samplings so far.
 
originally posted by Ian Fitzsimmons:
Yes, Mark; they emit hugely powerful x-ray beams, don't they - is that the same? A little knowledge is a dangerous thing. I guess in string theory, any unaccounted for energy can jump down the rabbit hole of one of the microscopic dimensions.

Anyway, thanks.
Click to expand...

But, on second thought, to maintain balance, the radiated energy would have to be equivalent to all the energy and matter approaching the event horizon; so that, in effect, nothing is captured in the hole's gravitational field, it's just converted to energy (if it was initially mass) and propelled away. That doesn't sound right.
 
originally posted by MLipton:
originally posted by Ian Fitzsimmons:
Yes, Mark; they emit hugely powerful x-ray beams, don't they - is that the same? A little knowledge is a dangerous thing. I guess in string theory, any unaccounted for energy can jump down the rabbit hole of one of the microscopic dimensions.

Anyway, thanks.
Click to expand...

They emit electromagnetic radiation across the whole spectrum. Quasars are now believed to be supermassive black holes at the centers of galaxies, and they are characterized not only by radio emission, but also by their superluminosity in the visible light range and by powerful X-ray and even gamma ray emissions.

Mark Lipton
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I hadn't heard that. Are they thought to be old, disk-less galaxies that are slowly orbiting into the hole, and therefore concentrating in space; or are they distinguished from other galaxies somehow by their manner of birth? Or something else?

If the holes radiate EM across the spectrum, why are they 'black?' Or is their visible spectrum radiation just extremely low.
 
Continuing with the off-topic theme: I've enjoyed reading Brian Greene - a vocal and eloquent proponent of some version or other of string theory. But I just bought Pedro G. Ferreira's The State of the Universe - A Primer in Modern Cosmology at our biggest bookshop's sale today. Anyone here read it?
 
originally posted by Ian Fitzsimmons:
originally posted by Ian Fitzsimmons:
Yes, Mark; they emit hugely powerful x-ray beams, don't they - is that the same? A little knowledge is a dangerous thing. I guess in string theory, any unaccounted for energy can jump down the rabbit hole of one of the microscopic dimensions.

Anyway, thanks.
Click to expand...

But, on second thought, to maintain balance, the radiated energy would have to be equivalent to all the energy and matter approaching the event horizon; so that, in effect, nothing is captured in the hole's gravitational field, it's just converted to energy (if it was initially mass) and propelled away. That doesn't sound right.
Click to expand...

Why would it have to be equivalent? The radiated energy is equivalent to the work performed by gravitational attraction. Any mass not radiated away as electromagnetic energy is added to the mass of the black hole. I see nothing in that that mandates a strict equivalence in mass/energy.

Mark Lipton
 
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