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Warp wrote:
> Because you can't have a huge bunch of particles in a space of zero
> volume.
The math for QM doesn't work out (so I've heard) if you assume particles
aren't points.
> 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).
That's fair. But I would more say "we don't know if they're still particles
or something else" than I would say "we know they can't be particles because
the math says there's zero space at the bottom of the well."
> (Of course I'm assuming here that singularities do exist. It's possible
> that reality is different and they don't.)
Yeah, that's really the only assumption I'm challenging. Lots of folks on
this thread are making assertions about what actually happens in places
where, by definition, you cannot observe what actually happens. :-)
> 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").
Sure. Except it's a singularity. There's a discontinuity in the mathematics
there. That's why it has that name. And the theories of gravity don't work
if space isn't continuous, and the theories of really small stuff don't work
if the space isn't discontinuous. So ... I think it's safe to say "we don't
know."
And, actually, the whole thing with the "holographic universe" bit is that
stuff really doesn't necessarily disappear when it goes into the black hole.
> 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.)
*Assuming* that space is continuous. But if there's a lower limit on "the
shortest distance" that isn't zero, then GR breaks down. And QED seems to
suggest there is such a limit, because QED breaks down when you assume the
shortest distance *is* zero.
> If GR breaks at the singularity, who is to say that QM doesn't?
We know it does, *if* you assume GR. That's exactly why people are looking
for a quantum version of GR. Because if you assume gravity can compress
things down arbitrarily small, then QED gives infinite energies for every
interaction, including those outside the event horizon.
> Maybe information *is* destroyed at the singularity? After all, it's
> pretty weird in there (being of zero size and all).
That would violate all sorts of symmetry laws. That's why they think it
doesn't happen. You lose all kinds of things like conservation of charge, as
well as (if I recall right) conservation of some properties that GR assumes
in its formulation, like conservation of momentum.
Of course, obviously something is wrong with the theories. We already know
that. That's why people are looking at string theory and other GUTs. It's
exactly these border conditions (infinite gravity, zero size) where the
theories break down. So I'm not convinced anyone can confidently assert what
*actually* happens, vs what the math implies should happen if the math is
still isomorphic with reality under those circumstances.
--
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 15:18:50 -0400, Warp wrote:
> Because you can't have a huge bunch of particles in a space of zero
> volume.
I'm not a physicist (though I know a few people who are), but ISTR
reading/hearing that a 'singularity' isn't defined as a space with zero
volume. It's a very densely packed collection of matter, but not with
zero volume.
Jim
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On Thu, 22 Jul 2010 12:37:02 -0700, Darren New wrote:
> Jim Henderson wrote:
>> <shrug> I just remembered hearing that it was beyond mere theory.
>
> Not according to *that* paper. :-)
It was the first hit that I ran across, and it sounded vaguely familiar,
but probably was something else. ;-)
Jim
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Am 22.07.2010 21:46, schrieb Darren New:
>> 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).
>
> That's fair. But I would more say "we don't know if they're still
> particles or something else" than I would say "we know they can't be
> particles because the math says there's zero space at the bottom of the
> well."
An interesting thought in this context is that the mass will never
actually reach the singularity state anyway as long as the universe
exists, due to the extreme warping of space-time.
>> 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").
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.
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Jim Henderson <nos### [at] nospam com> wrote:
> I'm not a physicist (though I know a few people who are), but ISTR
> reading/hearing that a 'singularity' isn't defined as a space with zero
> volume. It's a very densely packed collection of matter, but not with
> zero volume.
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.
--
- Warp
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Kevin Wampler <wam### [at] uwashingtonedu> wrote:
> I'm not sure I see anything in this quote which implies that the big
> bang is part of evolution. The most natural interpretation seems to be
> that "evolutionist" is used as a blanket term which can be used as a
> label for one who holds a set of related viewpoints of which evolution
> need only be a part.
Btw, here's a more concrete example of "evolution" (literally "evolution",
not "evolutionists") being equated to abiogenesis:
http://www.youtube.com/watch?v=FZFG5PKw504
"Evolution teaches that energy, such as lightning or heat, plus matter
can, occassionally, create new life."
Nope. Evolution teaches no such thing.
(The rest of the video is quite hilarious. Basically they are disproving
what science itself disproved in the 17th century...)
--
- Warp
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Darren New wrote:
> Yeah, that's really the only assumption I'm challenging.
Interestingly, I just stumbled across this, without even looking for it.
http://www.dailygalaxy.com/my_weblog/2010/07/did-time-exist-before-the-big-bang.html
--
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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Am 22.07.2010 22:17, schrieb Jim Henderson:
> On Thu, 22 Jul 2010 15:18:50 -0400, Warp wrote:
>
>> Because you can't have a huge bunch of particles in a space of zero
>> volume.
>
> I'm not a physicist (though I know a few people who are), but ISTR
> reading/hearing that a 'singularity' isn't defined as a space with zero
> volume. It's a very densely packed collection of matter, but not with
> zero volume.
Actually, AFAIK a "singularity" is defined as any condition in which the
formulae of a theory don't give any meaningful answer.
In GR, you can pack matter arbitrarily dense in any non-zero volume
without the formulae breaking down, so no - I guess you're wrong.
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.
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.
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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.
http://en.wikipedia.org/wiki/Renormalization
--
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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Jim Henderson <nos### [at] nospamcom> writes:
> Well, not really; a fair number of the creationists reject scientific
> principles. Atheists tend to know a lot more about theistic religions
> than those who practice them, IME, because they've often been raised in
> one and then decided it's pants after years of careful study and
> questioning - questioning that *often* is answered with "don't ask those
> kinds of questions!"
My experience is quite the opposite: The self-proclaimed atheists I've
interacted with often betray their lack of understanding of
religion. They sound far more like people who read books that are, for
lack of a better term, anti-religion, than from observation of the
world, or study of a religion.
They also had a terrible tendency to generalize: They see something
silly in one sect in one religion, and they generalize like
crazy.
Their rhetoric isn't helpful. They often ask religious people to defend
principles that those religious people don't always believe in, for
example. They didn't bother establishing whether the person they're
speaking to fits their mental model of a religious person. He merely
does, because he's religious.
No doubt, there are exceptions. As a few milder atheists are at pains to
point out: "Just as their are all kinds of religious folks, atheists are
not as monolithic as they seem. The vocal set just happen to be assholes."
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