clipka <ano### [at] anonymousorg> wrote:
> However, you may be not so far off the mark regarding black holes: 
> AFAIK, those indeed typically have a non-zero (though ever shrinking) 
> volume, as in order to form a true singularity you'd need a neatly 
> symmetric collapse.

  I think you are confusing singularities which are not points (which is
what happens in rotating black holes, AFAIK). Just because the singularity
is not a point (but eg. a ring) doesn't mean it doesn't have zero volume.
A torus can have zero volume if the minor radius is zero (and that, IIRC,
is precisely what the GR equations tell about a rotating black hole).

http://en.wikipedia.org/wiki/Ring_singularity

> Thus, the problem with black holes is probably not the singularity /per 
> se/: To me it looks like that's a purely academic issue because there 
> bloody likely aren't any such beasts out there in reality. Instead, the 
> problem with black holes is that ever-shrinking thing, which doesn't go 
> along well with QED's prediction of a lower bound on distances.

  I'm not sure what you mean by "ever-shrinking".

-- 
                                                          - Warp

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Patrick Elliott <sel### [at] npgcablecom> wrote:
> Special pleading. That is all I have to say on that. If you don't get 
> them, you don't have to make up some *unknown*, and *undefined* thing 
> for matter to "be" when its in one.

  But assuming the opposite would require an *unknown* and *undefined*
phenomenon of physics which stops matter from collapsing into a singularity.

-- 
                                                          - Warp

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clipka <ano### [at] anonymousorg> wrote:
> I think there's a flaw in here, too: The event horizon itself is subject 
> to relativity as well. An observer approaching the black hole in free 
> fall will witness the event horizon to "dent in" in front of him, even 
> when he himself has already passed the event horizon as witnessed from a 
> far-away observer.

  I think you have got it completely reversed.

  An external observer will never see a falling object crossing the event
horizon. This is because from the external observer's point of view the
time of the falling object slows down as it approaches the event horizon.
The time of the falling object completely stops (from the external
observer's point of view) when it reaches the event horizon (which, in
fact, never happens, as the speed of time approaches zero asymptotically).
So from the external observer's point of view the falling object flattens
into a disc and its time practically stops as it approaches the event
horizon, and it "never" crosses it.

  (Of course this is purely under the theoretical assumption that the
external observer could observe the falling object for eternity. This
isn't so in practice because the falling object also red-shifts to black
(again, from the point of view of the external observer) as it approaches
the event horizon, and at some point becomes completely impossible to
observe from the outside.)

  The falling object itself experiences no such slowing of time. From its
*own* point of view time continues just normally. It's the time of the rest
of the universe which seems to go haywire.

  What the falling object sees as it approaches the event horizon is that
it looks as if the event horizon engulfs the falling object (due to how
light bends near to the event horizon). As the falling object approaches
the event horizon it looks as if the black hole increases in size more
rapidly than the falling speed would dictate. At some altitude (but still
outside of the event horizon) it looks as if the event horizon is a
completely flat plane that takes half of the entire universe (the visible
part of the universe having been "squeezed" to the other half). As it
continues to approach the event horizon, it looks as if the event horizon
bends up, "compressing" the visible universe into an ever-shrinking circle.

  Just as the falling object touches the event horizon the circle-shaped
"viewport" of the universe closes and the event horizon seems to completely
surround everything. Then the object passes the event horizon and is now
inside it.

  After that it's all weird.

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
>   I have always wondered why it seems that quantum mechanics is somehow
> considered "holier" than general relativity. If some physical phenomenon
> is predicted which seems to contradict either one or the other, or both,
> then it must be GR which breaks, never the "holy" QM, which never breaks
> and is always in effect no matter what the circumstances.

  I came up with a humorous explanation for that.

  Quantum physicists don't really like gravity. After all, it's such an
insignificant force at quantum scales that it can be completely left out
of equations and it doesn't change anything. It's way, way weaker than
even the second weakest interaction of the four, and plays no significant
role at all at quantum levels. Thus those puny astrophysicist can keep
their gravity, it doesn't affect us.

  But then astrophysicist say that hey, GR actually predicts this phenomenon
where gravity actually becomes a significant force. Not only that, it
actually becomes so significant that it completely overwhelms all the
other forces, including strong interaction. Take that, you quantum physicists.
Your move.

  Quantum physicists take this as an invasion of privacy. Those puny
astrophysicists are invading their realm! They could have the *entire
universe* with all the stars and planets and everything, but no, they
can't be content with that, they have to invade our world too with their
annoying theories and equations. But we won't go out without a fight!
Quants cannot lose the battle to gravity!

-- 
                                                          - Warp

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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Warp wrote:
>>>   According to GR you would need an infinite amount of energy to maintain
>>> a shape with non-zero volume. Obviously there isn't an infinite amount of
>>> energy inside a black hole.
> 
>> Interestingly, according to QM, you need an infinite amount of energy if two 
>> particles can be zero distance from each other.  And that is *exactly* the 
>> problem.
> 
>   I suppose the apparent contradiction won't be solved until a unified
> theory is discovered.

Or until we figure out how to make a black hole we can actually observe the 
behavior of, etc. :-)  I think QM is more "holy" than GR because it's very 
difficult to observe the actual behavior of GR in the extreme. We have only 
theories of what goes on inside a black hole's even horizon, whereas QM has 
been expermentally validated to a much greater extent with actual 
observations, perhaps?

-- 
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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Neeum Zawan wrote:
> Which is my point: They (at least the loud atheists) tend not to know
> much about religion.

I think the guys who wrote the books (Hitchens, Dawkins, etc) probably 
studied it pretty well.

-- 
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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Darren New <dne### [at] sanrrcom> wrote:
> I think QM is more "holy" than GR because it's very 
> difficult to observe the actual behavior of GR in the extreme. We have only 
> theories of what goes on inside a black hole's even horizon, whereas QM has 
> been expermentally validated to a much greater extent with actual 
> observations, perhaps?

  But not in those extreme conditions...

-- 
                                                          - Warp

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On Sat, 24 Jul 2010 08:35:54 -0700, Darren New wrote:

> Neeum Zawan wrote:
>> Which is my point: They (at least the loud atheists) tend not to know
>> much about religion.
> 
> I think the guys who wrote the books (Hitchens, Dawkins, etc) probably
> studied it pretty well.

Those are the ones I think of when I think of the "loud" atheists.

Jim

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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> I think QM is more "holy" than GR because it's very 
>> difficult to observe the actual behavior of GR in the extreme. We have only 
>> theories of what goes on inside a black hole's even horizon, whereas QM has 
>> been expermentally validated to a much greater extent with actual 
>> observations, perhaps?
> 
>   But not in those extreme conditions...

Agreed, certainly.  I just think that's why GR is considered less 
well-established. We haven't actually built any gravitic engineering 
projects. If we actually had black hole power plants like we have QM 
transitors, I think we'd probably have much less tendency to favor QM over GR.

(I once had a sci-fi scenario where the power plants were quantum black 
holes into which you could feed any sort of matter you wanted and get out 
hot hawking radiation to power your tech. I wonder if that might actually 
work. :-)

And we have the ability to build the extreme quantum conditions, like cosmic 
rays or the LHC.  We don't really have the ability to build extreme gravity 
conditions yet.

-- 
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 7/23/2010 10:27 PM, Warp wrote:
> Patrick Elliott<sel### [at] npgcablecom>  wrote:
>> On 7/22/2010 11:02 AM, Warp wrote:
>>>> 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.
>>>
>> Based on what? Observation?
>
>    Pretty much, yes. Observation in the sense that GR has hold up pretty
> well in a very large amount of different experiments (including things
> like gravitation lensing and orbital measurements of the Moon).
>
Same argument could have, at one time, been made about Newtonian 
physics. The first examples of where that didn't work where people 
going, "Yeah, but.. what about in this case?"

>    To say that singularities can't exist you would have to demonstrate
> somehow that GR stops working when matter density goes high enough (but
> is still finite). AFAIK no such observation has been made, so the *simpler*
> explanation at this moment is to assume that GR does hold even with
> extremely high densities because it doesn't require any additional, yet
> unknown, physical models.
>
Yes it does, it requires matter and energy (which is generally the same 
thing) to achieve some undefined state, it requires violations of other 
physical rules, like particles holding the same point in space, and a 
whole host of other "unexplained" things. Last I checked they didn't 
have even the math to describe what things actually look like past the 
event horizon, never mind explain what, if anything, the core ends up 
being made of, since it obviously, isn't likely particles. There are 
problems with the theory, once you get past the point where you can even 
theoretically observe, predict, etc., the outcome. Even the explanations 
go something like, "And then once you travel past the horizon you get 
torn apart and there is nothing but chaos.", which is a fairly lame way 
of saying, "We don't have a damn clue, but something has to happen, and 
its the only thing we can think of, if GR applies." That's not even a 
description, its a wild guess, with no details at all.

>    One known physical model is simpler than one known plus one unknown
> (especially when there's no experimental observation of where the latter
> becomes more prominent than the former, so drawing the line between the
> two is pretty much impossible).
>
But, its **not** known. You yourself admit, mind, as a layman, that you 
have no clue what "is" in the core of a black hole. I can say, as 
someone that reads a lot about it, that the physicists don't have much 
better idea. At best, they can point to some sort of QM, which doesn't 
really give them any better idea, or string theory, which many are not 
sure even describe a real thing, and can't make predictions, of *any* 
sort, etc. They don't know. A chart of a black holes structure might as 
well be an ancient map, with the center marks, "Here be dragons."

-- 
void main () {

     if version = "Vista" {
       call slow_by_half();
       call DRM_everything();
     }
     call functional_code();
   }
   else
     call crash_windows();
}

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