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Zero-energy_universe doesnt add up

  1. Nov 7, 2011 #1
    http://en.wikipedia.org/wiki/Zero-energy_universe

    Hawking is probably right, however

    the energy in the gravitation field of an elliptical galaxy is approximately:
    E = Gm2/r

    where G = 6.67×10-11 N m2/kg2

    and of course E = mc2

    so using r = 1021 m (100,000 Light years) we get

    Gm2/r = mc2

    m = r * c2 / G

    m = 1.347×1048 kg = 6.774×1017 solar masses

    thats 6 * 104 times larger than the largest elliptical galaxies
    So in order to break even you need 60,000 galaxies worth of mass in a region of space only 100,000 Ly across.
     
    Last edited: Nov 7, 2011
  2. jcsd
  3. Nov 7, 2011 #2

    Chronos

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    Read the intro to the wiki article again. The zero energy hypothesis is derived using pseudo tensors.
     
  4. Nov 7, 2011 #3
    Feynman and others have long puzzled over the zero energy universe - in his "Lectures On Gravity" he comes back to it serval times in different chapters. At one point he comments that it is an exciting prospect that it costs nothing to create a mass at the center of the universe (which is everywhere) because the mc^2 energy is always balanced by the negative gravitational energy.

    So perhaps the thing we call the big bang didn't create anything - it just rearranged things
     
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