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Jim Henderson wrote:
> Essentially, this is a simulated observation that demonstrates the theory
> of Hawking radiation is sound.
So, what you're saying is, Hawking used math to predict hairy black holes.
Carusotto took the same math applied to a Bose condensate, and predicted
you'd see the same sort of effect from it, without actually creating a Bose
condensate in the laboratory.
And this shows that black holes emit radiation?
Hey, my math says I can build a Wells-type time machine. And look, they even
made a movie of it, so that proves it would work!
--
Darren New, San Diego CA, USA (PST)
C# - a language whose greatest drawback
is that its best implementation comes
from a company that doesn't hate Microsoft.
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Patrick Elliott wrote:
> If its not particles, then what? Energy? Oh, wait, energy is still some
> sort of particle, as near as we can come up with.
Well, that's sort of what the LHC is looking for, so I'm pretty sure the
jury is still out on that one.
> combined with the embarrassing fact that certain
> observations are not explained, by other means, without the prior
> Hawking's Radition.
Like what, out of curiousity. I wasn't aware we'd managed to find a black
hole small enough that the hawking radiation effect would work.
--
Darren New, San Diego CA, USA (PST)
C# - a language whose greatest drawback
is that its best implementation comes
from a company that doesn't hate Microsoft.
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Patrick Elliott wrote:
> This is one reason why singularity is a problem.
I'm sorry, but your writing is so bad, I can't even figure out what you're
trying to say.
--
Darren New, San Diego CA, USA (PST)
C# - a language whose greatest drawback
is that its best implementation comes
from a company that doesn't hate Microsoft.
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Patrick Elliott <sel### [at] npgcable com> wrote:
> If its not particles, then what? Energy? Oh, wait, energy is still some
> sort of particle, as near as we can come up with.
Energy is quantized in normal circumstances. However, at a singularity,
if they exist, all physics break up. There's nothing to say that energy
is still quantized at a singularity. (The *amount* of energy in a singularity
might be a multiple of an energy quantum, but that doesn't mean that the
energy is subdivided into quantized parts in there.)
> In any case, no, the problem here is that you have to present a
> plausible thing to "be" there, if you don't have particles, given that
> even breaking up something like an electron gives you... more particles.
Matter/energy degenerates under such enormous gravity, forming something
which doesn't happen normally elsewhere. It retains certain properties
(such as mass) because energy cannot be destroyed nor created, but its
physiology may be completely different than normally.
It's the same as what happened in the first moments of the Big Bang.
There were no particles until later.
> Again, its presupposing what is there, based on what needs to be, for
> the math to come out right. It doesn't prove that the math *is* right,
> in those conditions, or there is some basic limit, just like with
> distance and travel, over time. There is simply the assumption that
> there isn't one.
Well, as long as you can't present a plausible alternative, I'd say
the Occam's Razor applies...
--
- Warp
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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > Matter degenerates under that much gravity. They are not "particles"
> > anymore.
> Err, what are they, then?
How should I know? I'm not an astrophysicist.
> > Besides, it doesn't really matter what happens to them. You would have
> > to prove that there exists a phenomenon or force in physics which makes
> > matter overcome the gravity and stops it from collapsing into a singularity
> > inside a black hole. I don't think any such phenomenon or force has been
> > observed or even plausibly conjectured.
> I would think Pauli exclusion would be a possibility.
That kicks in up to a certain point. It's what happens in neutron star
cores, where particles are as close to each other as they can be without
breaking the Pauli exclusion principle.
However, even this exclusion principle doesn't exert an infinite force
on particles, and if the gravity is larger than the critical limit, the
matter just collapses and there's nothing to stop it. (AFAIK according to
the relativistic equations you would need literally an infinitely strong
force to keep matter inside the event horizon from falling into the
singularity. Thus no kind of non-zero-sized shape can be maintained in
there.)
> Or something like the
> quantumness of spacetime. Can you actually fit multiple particles into one
> plank-length of space?
Since there is currently no unifying quantum theory of gravity, nothing
definitive can be said about that, I think.
> > You would need to explain what stops the matter from collapsing into a
> > singularity. It certainly cannot be a physical force.
> I think first you have to define what you mean by a "singularity", then by a
> "force", given that gravity isn't a force per se.
> I think once you wander outside the area where the math actually is known to
> work, you need some actual experimental evidence to base conclusions on. I
> don't know that it's valid to say "that must behave *this* way, because
> otherwise we'd divide by zero" (or "because we divide by zero"). The math
> only summarizes what we know of physics. It doesn't define how physics works.
The math seems to work everywhere else, so without evidence of the
contrary the simpler assumption is that it works everywhere.
--
- Warp
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Patrick Elliott <sel### [at] npgcablecom> wrote:
> The funny thing on that is, the average "believer" I know has maybe read
> 20% of the Bible, almost **nothing** on the history tied to the time
> periods described in it (with possible exception of texts designed to
> ignore things that don't fit in with the "official" dogma), where as
> most atheists have read more than half of it, or the entire thing, more
> than once, and at least 1-2 books on the history of some of the periods,
> *and* more than a few books on other religions. The other thing is, like
> 95% of atheists used to be believers, probably 20% of them where
> Evangelical, before concluding it was all gibberish, and another 2% or
> so where ***actually priests*** at one point in time.
I'm wondering if you are talking about Americans there.
Here the majority of people are atheists, and from them, the vast majority
have always been. And only a very, very small percentage have ever even
opened the Bible. (Yes, while in the US people are by default christians,
atheism being the rare exception, here people are by default secular,
religion being the exception. It might be hard for an American to fathom,
but it is really a bit surprising if someone claims being a believer, as
the assumed status quo is being secular. I suppose some American atheists
could call this a paradise of sorts.)
--
- Warp
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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Warp wrote:
>>> Matter degenerates under that much gravity. They are not "particles"
>>> anymore.
>
>> Err, what are they, then?
>
> How should I know? I'm not an astrophysicist.
Why do you think they aren't particles, then?
> However, even this exclusion principle doesn't exert an infinite force
> on particles,
I'm not sure that's true - the probability in the math that two
(appropriate) particles occupy the same location is indeed zero. Now, what
happens when there isn't any space for them not to be apart, I'm not sure.
> and if the gravity is larger than the critical limit, the
> matter just collapses and there's nothing to stop it. (AFAIK according to
> the relativistic equations you would need literally an infinitely strong
> force to keep matter inside the event horizon from falling into the
> singularity. Thus no kind of non-zero-sized shape can be maintained in
> there.)
Yeah. I'm not arguing that any one thing happens or doesn't. I'm just trying
to figure out why people seem to be asserting that we know what happens in
the middle of a singularity (where the math doesn't apply or conflicts with
other theories that have just as much or more evidence in their favor).
>> Or something like the
>> quantumness of spacetime. Can you actually fit multiple particles into one
>> plank-length of space?
>
> Since there is currently no unifying quantum theory of gravity, nothing
> definitive can be said about that, I think.
Right. So applying relativity where we already know it doesn't apply doesn't
seem to be supportable, scientifically speaking.
> The math seems to work everywhere else, so without evidence of the
> contrary the simpler assumption is that it works everywhere.
Well, no, it doesn't work everywhere else.
That's how we know QED and GR aren't compatible and why we need to find a
quantum theory of gravity. GR does *not* work at quantum scales. It assumes
space is continuous, and QED only works if you assume space is
discontinuous. (Or, rather, QED gives nonsensical answers if you calculate
it assuming that indefinitely small distances in space are possible.)
It's also the case that when you get down to zero size, if you mash
everything into a single point, then you start violating the duality
principle (if I understand correctly) as well as a whole bunch of symmetry
laws, which is why there's now all kinds of talk about holographic
information on the surface of black holes and such.
It's like saying "Well, arctangent works for every other angle. Why wouldn't
we assume it works for 90 degrees?" Well, that's why it's called a
"singularity". There's a point in the math where the math does *not* work,
precisely because you wind up with equations with zeros in the denominator.
--
Darren New, San Diego CA, USA (PST)
C# - a language whose greatest drawback
is that its best implementation comes
from a company that doesn't hate Microsoft.
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On Thu, 22 Jul 2010 10:37:06 -0700, Darren New wrote:
> Jim Henderson wrote:
>> Essentially, this is a simulated observation that demonstrates the
>> theory of Hawking radiation is sound.
>
> So, what you're saying is, Hawking used math to predict hairy black
> holes. Carusotto took the same math applied to a Bose condensate, and
> predicted you'd see the same sort of effect from it, without actually
> creating a Bose condensate in the laboratory.
>
> And this shows that black holes emit radiation?
>
> Hey, my math says I can build a Wells-type time machine. And look, they
> even made a movie of it, so that proves it would work!
<shrug> I just remembered hearing that it was beyond mere theory.
Jim
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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> > Darren New <dne### [at] sanrrcom> wrote:
> >> Warp wrote:
> >>> Matter degenerates under that much gravity. They are not "particles"
> >>> anymore.
> >
> >> Err, what are they, then?
> >
> > How should I know? I'm not an astrophysicist.
> Why do you think they aren't particles, then?
Because you can't have a huge bunch of particles in a space of zero
volume. Hence if all the mass is in a singularity, it cannot be in the
form of particles, but something else completely (basically something
that cannot be described with current knowledge of physics).
(Of course I'm assuming here that singularities do exist. It's possible
that reality is different and they don't.)
> > and if the gravity is larger than the critical limit, the
> > matter just collapses and there's nothing to stop it. (AFAIK according to
> > the relativistic equations you would need literally an infinitely strong
> > force to keep matter inside the event horizon from falling into the
> > singularity. Thus no kind of non-zero-sized shape can be maintained in
> > there.)
> Yeah. I'm not arguing that any one thing happens or doesn't. I'm just trying
> to figure out why people seem to be asserting that we know what happens in
> the middle of a singularity (where the math doesn't apply or conflicts with
> other theories that have just as much or more evidence in their favor).
People don't claim to know what happens in the singularity. They claim that
the equations say something about what happens *outside* the singularity
(and that "something" is, basically, "there can't be anything inside the
event horizon and outside the singularity, hence the only possible place
where everything must be is in the singularity, because that's where all
the space-time geodesics are pointing to").
> >> Or something like the
> >> quantumness of spacetime. Can you actually fit multiple particles into one
> >> plank-length of space?
> >
> > Since there is currently no unifying quantum theory of gravity, nothing
> > definitive can be said about that, I think.
> Right. So applying relativity where we already know it doesn't apply doesn't
> seem to be supportable, scientifically speaking.
Relativity cannot be applied to the singularity itself, but it can be
applied to the space between the event horizon and the singularity. (It's
all really weird there, and greatly complicated by things like rotation
and electric charge, but calculable.)
> It's also the case that when you get down to zero size, if you mash
> everything into a single point, then you start violating the duality
> principle (if I understand correctly) as well as a whole bunch of symmetry
> laws, which is why there's now all kinds of talk about holographic
> information on the surface of black holes and such.
If GR breaks at the singularity, who is to say that QM doesn't?
Maybe information *is* destroyed at the singularity? After all, it's
pretty weird in there (being of zero size and all).
--
- Warp
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Jim Henderson wrote:
> <shrug> I just remembered hearing that it was beyond mere theory.
Not according to *that* paper. :-)
--
Darren New, San Diego CA, USA (PST)
C# - a language whose greatest drawback
is that its best implementation comes
from a company that doesn't hate Microsoft.
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