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B The age of the Universe

  1. Apr 11, 2017 #1
    With the life of a proton exceeding 10 to the 34 years and the electron even greater why can't we assume the universe is eternal and the big bang a fluctuation in that duration? Its no more difficult to consider an eternal universe as it is a finite one with nothing coming before as it seems that it will never end.
     
  2. jcsd
  3. Apr 11, 2017 #2
    I guess it depends on how infinite your infinity has to be.
    The largest black holes will take 10 ^ 100 to evaporate.
    See https://en.wikipedia.org/wiki/Heat_death_of_the_universe#Time_frame_for_heat_death
     
  4. Apr 11, 2017 #3

    Orodruin

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    I do not quite see how you make this inference. That the proton has a lifetime larger than ##10^{34}## years by no means implies that the universe must be eternal.

    Edit: Nobody has observed a proton for ##10^{34}## years. The proton mean-life (or bounds on it) are inferred from observing a large number of protons. Particle decays work according to an exponential distribution and if the mean-life would be ##10^{x}## years and you observed ##10^{x}## particles for one year, you would expect one of those particles to decay.
     
  5. Apr 11, 2017 #4

    Chalnoth

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    This is a good read on the subject:
    https://en.wikipedia.org/wiki/Future_of_an_expanding_universe

    The short version of the above, in relation to your question, is that proton decay doesn't change the overall picture: it's more a detail than a big change to the overall picture.
     
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