| Topic: |
Science > Physics |
| User: |
"Physitrex" |
| Date: |
23 Nov 2005 03:32:14 AM |
| Object: |
Spacetime and matter |
duh, are matter and spacetime two different things ? The impression I get is
that matter is something that deforms space-time causing gravity. What is
the relationship of matter to space-time ? I have this image in my head that
matter is something like a marble that sits on top of a space-time surface.
Why does it stick to the surface ? Wouldn't there have to be some sort of
friction that holds it there ? If there is some sort of friction couldn't
there be slippage and heat generation ? Is the friction perfect ? What is
the frictive force ?
Let's say a star is sitting on the edge of a gravity well caused by a black
hole. If the gravity well suddenly gets larger and spacetime gets stretched
under the star, is the star stuck to the spacetime surface and just starts
rolling down into the black hole ? Or could space-time actually slip under
the star ?
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| User: "Mr Clarke" |
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| Title: Re: Spacetime and matter |
26 Nov 2005 03:58:44 PM |
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"Physitrex @sympatico.ca>" <physitrex<remove> wrote in message
news:xGWgf.3493$e43.233387@news20.bellglobal.com...
duh, are matter and spacetime two different things ? The impression I get is
that matter is something that deforms space-time causing gravity. What is
the relationship of matter to space-time ? I have this image in my head that
matter is something like a marble that sits on top of a space-time surface.
That`s funny, I have an image in my head that matter is real and time isn`t.
-----------------------------------------------------------------------
Ashley Clarke
-------------------------------------------------------
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| User: "Jeff_Relf" |
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| Title: Gravity is a glomming on, a type of consumption. |
23 Nov 2005 04:45:15 AM |
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Hi Physitrex,
Mass_Energy determines the Geometry of Space_Time, not just space.
That's four very _Spatial_ dimensions warping into a fifth, Entropy,
....Space_Time_Entropy.
Recent supernovae data has made Einstein's so_called Greatest_Blunder, lambda,
the leading theory of the cosmos... but much more data is still needed.
WikiPedia.ORG has this to say:
Adding a cosmological constant to the standard theory of cosmology
...has led to a model for cosmology known as the Lambda-CDM model.
This model is in very good agreement with
established cosmological observations.
__ http://en.wikipedia.org/wiki/Dark_energy
and:
In spite of its problems, the cosmological constant is in many respects
the most economical solution to the problem of cosmic acceleration.
One number successfully explains a multitude of observations.
Thus, the current standard model of cosmology, the Lambda-CDM model,
includes the cosmological constant as an essential feature.
__ http://en.wikipedia.org/wiki/Dark_energy#Cosmological_constant
Like Einstein, I posit that physical processes determine absolutely everything.
Randomness is only incomplete information... an incomplete map, if you will.
Order, randomness, slavery and freedom are merely _Notional_, not physical.
I posit that Gravity and long_lived protons are
left over density from the _Notional_ start of the big bang.
If the density of photons could be measured,
and if we could somehow track 10 ^ ( 10 ^ 9999 ) particles all at once,
and if General_Relativity could be extended to handle such complexity,
....ha ha... it'd replace today's theory of Quantum_Mechanics.
Gravity is like a casino... as is life.
Entropy is the fifth _Spatial_ dimension, everything just dissipates.
Each only wins in the Short_Run, never the Long_Run.
Each consumes and is consumed, its birth and death determined by others.
All any ever did was burn bright, like a star, dissipating into the night.
Gravity is a glomming on, a type of consumption.
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| User: "" |
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| Title: Re: Gravity is a glomming on, a type of consumption. |
23 Nov 2005 06:16:55 AM |
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Duckie would agree.
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| User: "Ben Rudiak-Gould" |
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| Title: Re: Spacetime and matter |
23 Nov 2005 08:45:02 AM |
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Physitrex <physitrex wrote:
duh, are matter and spacetime two different things ? The impression I get is
that matter is something that deforms space-time causing gravity. What is
the relationship of matter to space-time ?
Nobody knows. The mathematical relationship is that G_uv = T_uv at every
point in spacetime, where G_uv is a function of the spacetime curvature at
that point and T_uv is a function of the matter present at that point. But
G_uv doesn't tell you everything about the curvature (it omits gravitational
waves, for example), and T_uv doesn't tell you everything about the matter
distribution (it doesn't distinguish matter from antimatter, for example).
So neither curvature by itself nor matter by itself tells the whole story.
Einstein spent the latter half of his life trying to come up with a theory
in which curvature told the whole story. String theory tries to make matter
tell the whole story. Probably it's a false dichotomy.
I have this image in my head that
matter is something like a marble that sits on top of a space-time surface.
I would forget about that image. It's likely to be more confusing than
helpful. It's certainly not literally true. If anything, matter is embedded
in spacetime. A spacetime surface doesn't have a top. There's no
higher-dimensional space that spacetime curves in. (Well, there might be,
but I doubt it. In GR there certainly isn't.)
Why does it stick to the surface ? Wouldn't there have to be some sort of
friction that holds it there ? If there is some sort of friction couldn't
there be slippage and heat generation ? Is the friction perfect ? What is
the frictive force ?
All good reasons to forget that image. :-)
-- Ben
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| User: "Sam Wormley" |
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| Title: Re: Spacetime and matter |
23 Nov 2005 08:25:44 AM |
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Physitrex <physitrex wrote:
duh, are matter and spacetime two different things?
You can't have one without the other. Einstein's relativity
relates space, time and gravity.
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