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Re: infinite universe

Subject: Re: infinite universe
From: Sam Wormley
Date: Thu, 02 Mar 2006 13:24:17 GMT
Newsgroups: sci.astro, sci.physics
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

    Our Universe Has a Topology Scale of at least 24 GPC

      Our universe has a topology scale of at least 24 Gpc, or
      about 75 billion light years, according to a new analysis
      of data from the Wilkinson Microwave Anisotropy
      Probe (WMAP).

      What does this mean? Well, because of conceivable
      hall-of-mirrors effects of spacetime, the universe might
      be finite in size but give us mortals the illusion that it is
      infinite. For example, the cosmos might be tiled with
      some repeating shape, around which light rays might
      wrap themselves over and over ("wrap" in the sense
      that, as in video games, something might disappear off
      the left side of the screen and reappear on the right

      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.
      If the universe were finite and actually smaller than the
      distance to the "surface of last scattering" (a distance
      that essentially constitutes the edge of the "visible
      universe," and the place in deep space whence comes
      the cosmic microwaves), then multiple imaging should
      show up in the microwave background.

      But no such correspondences appeared in the analysis.
      The researchers are able to turn the lack of recurring
      patterns into the form of a lower limit on the scale of
      cosmic topology, equal to 24 billion parsecs, a factor of
      10 larger than previous observational bounds. (Cornish,
      Spergel, Starkman, Komatsu, Physical Review Letters,
      upcoming article; contact Neil Cornish, 406-994-7986,
      [email protected])

       No Center

       Also see Ned Wright's Cosmology Tutorial

       WMAP: Foundations of the Big Bang theory

       WMAP: Tests of Big Bang Cosmology

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