Re: The end of time (as we know it).
- From: Ye Old One <usenet@xxxxxxxxx>
- Date: Mon, 15 Jun 2009 20:53:35 GMT
On Mon, 15 Jun 2009 14:39:24 -0400, "Perplexed in Peoria"
<jimmenegay@xxxxxxxxxxxxx> enriched this group when s/he wrote:
"Ye Old One" <usenet@xxxxxxxxx> wrote:
[snip excellent summary of the standard story]
Well, it really does look like the universe will go on expanding. As
it does our horizon of view-ability (the distance we can see, limited
by the speed of light and the age of the universe) will expand as
well. However, those objects near to the horizon will be appearing to
move away from us at speeds greater than the speed of light, so they
will vanish, eventually, many billions of years from now, all that
will remain in our field of visibility will be our own local cluster
of galaxies. [snip more of the excellent summary]
This raises lots of questions in my mind. Is there still a cosmic
microwave background at this point?
Although it would still, in theory, exist, it would be so close to
absolute zero as to be totally unmeasurable.
Would it be isotropic?
If a new instance of intelligent life were to evolve in that era,
would they be able to detect the expansion of the universe?
I don't think so.
More questions: At one point, I read that the distribution of
galaxies in the universe exhibits a 'foam' structure. Is this
still the story? If so, it seems to me that at some stage of the
expansion, everything except our own sheet of 'soap film'
will have passed over the horizon - but we still have plenty
of galaxies to see besides our local cluster.
If more than the local group remain gravitationally linked then we
need to know more about dark energy before that question can be
answered.
At that stage, the matter in the visible universe will seem to
be limited to a two-dimensional sheet - with pretty much
nothing at all present in the 'polar' directions.
No, why do you think that would be the case?
Space will
be (or will appear to be) very anisotropic. And the Newtonian
gravitational field pulling everything outside the plane into the
plane will be huge. I keep thinking about the things I read
about Kaluza-Klein and GR back when I was interested in
string theory. Apparently, space once had ten dimensions.
Or eleven.
But it wasn't perfectly isotropic so everything collapsed
in some directions down to the Planck length in thickness.
The number of dimensions of space was reduced from 10
to 6, and then as more collapse took place to 3. Some
dimensions got crushed - others experienced inflation.
And thus was born the bestiary of elementary particles and
forces that we know today in 3+1 dimensional spacetime.
At least that is the story as I understood it.
A lot of that is mathematical ideas that are far from universally
accepted.
So, my question is, is it possible that we may yet be in for
another crunch - from 3 dimensions down to 2?
No, I do not think so. In fact the reverse could be true.
--
Bob.
.
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- From: Ye Old One
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