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Re: infinite universe

Subject: Re: infinite universe
From: John Bailey
Date: Thu, 02 Mar 2006 14:14:28 GMT
Newsgroups: sci.astro, sci.physics
On Thu, 02 Mar 2006 13:24:17 GMT, Sam Wormley <swormley1@xxxxxxxxx>
wrote:

>Bernhard Kuemel wrote:
>> Hi sa, sp!
>> 
>> A friend learned in school that 69! is bigger than the number of
>> atoms in the universe. "Nonsense!" I said, "The universe is
>> infinite, so it has infinite atoms."
>> 
>> After some research it turned out that it is unknown if the universe>> is 
>> finite or infinite...

>
>     Physics News Update -- Number 685, May 12, 2004
>     by Phil Schewe and Ben Stein
>     Ref: http://www.aip.org/pnu/2004/685.html
>
>     Our Universe Has a Topology Scale of at least 24 GPC
>
(snip)
>       A new study by scientists from Princeton, Montana
>       State, and Case Western looks for signs of such
>       "wrapped " light in the form of pairs of circles, in
>       opposite directions in the sky, with similar patterns in
>       the temperature of the cosmic microwave background.
(snip)
>       But no such correspondences appeared in the analysis.

Good summary!

Earlier last year I realized that a smooth, isotropic finite universe
lent itself to simple ray tracing and led to the conclusion that it
must be an expanding hyperspherical surface embedded in 4D space.
Further,on tracing the rays, the sky would necessarily contain images
of itself and its complement from prior epochs.

Later, I learned about the pairs-of-circles observation and its null
outcome.  In that context however, I find it hard to reconcile smooth,
isotropic, no-boundary universe with any topology that could result in
such circles.  

Currently, I am being updated by (reading) Susskind to the effect that
this universe may be the happy (for a few of us)  result of an
on-going process of creation involving myriad pocket universes, some
few of which have the critical parameters which support intelligence
and life. arXiv:hep-th/0302219, arXiv:hep-th/0408133

In the context of such a multiverse, the finite/infinite question of
the IP becomes a matter of definition--at what time? and within what
boundary of observation.  IIRC older cosmologies gave the estimate
(with scant proof) of 10^50 particles in the universe. Some multiverse
advocates  might give the estimate of 10^50 universes within the
multiverse.


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