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Initial size of universe

  1. Jul 30, 2004 #1
    Is it possible for the universe to expand from a very large initial size such as 10^25 metres instead of from the usual 10^-35 metres.
    Could the universe have a high enough temperature at 10^25 metres?
    Would nucleosynthesis of the elements give the right abundances?
    My motivation for asking this is as follows:

    (1) Wouldn't a large initial radius for the universe overcome the horizon problem?

    (2)A large initial radius would explain why the dark energy density and
    the baryonic matter density are so similar today.

    These are not unreasonable questions given that there is so little evidence for the theory of inflation.
     
  2. jcsd
  3. Jul 30, 2004 #2
    I think it is a very interesting question in the case that there can be infinitely many different Plank-like constants, where each constant is the initial unit of another universe.

    In this case we can ask if there can be any connection between two universes, which are based on different Plank-like constants.
     
    Last edited: Jul 30, 2004
  4. Jul 30, 2004 #3
    with metaphysical questions kurious?

    Is it not a metaphysical question to suppose the universe had a beginning?
    Should we ask that question in a scientific forum?
    Is it not that question part of the reason why our prevailing paradigm is askew?

    Regards

    EP
     
  5. Jul 30, 2004 #4

    Chronos

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    You would probably find a fair percentage of theorists believe the universe has always been infinite in size.
     
  6. Jul 30, 2004 #5
    Would an infinite Creator create a finite universe?

    Regards

    EP
     
  7. Jul 31, 2004 #6
    If its a metaphysical question or not doesn’t really matter. If you haven’t noticed these are the question physicists deal with everyday.

    Unless you agree with the Popes advice given to physicists in a conference in 1981 that we should not inquire into the big bang itself because that was the moment of creation and thus the work of god.
     
  8. Jul 31, 2004 #7
    It is only a metaphysical question like every other question until experimental evidence is found for it.I think dark energy holds the key to how big,small old and young the universe gets.If the issue of dark energy is resolved in the next few years we will be
    privileged to be living at a time when some of the questions that people have asked
    for thousands of years are answered.
     
  9. Jul 31, 2004 #8
    Hi kurious,

    Please look at post #2.
     
  10. Jul 31, 2004 #9
    Paraphrasing Chronos I would say:

    You would probably find a fair percentage of theorists and physicists are working with metaphysical questions, as they gave up given a mathematical description of their theories.

    Regards

    EP
     
  11. Jul 31, 2004 #10
    All their theories are based on mathematics, it's philosophers who need mathematical experience to understand these theories…
     
  12. Jul 31, 2004 #11
    Lama:
    I think it is a very interesting question in the case that there can be infinitely many different Plank-like constants, where each constant is the initial unit of another universe.

    In this case we can ask if there can be any connection between two universes, which are based on different Plank-like constants.

    Kurious:
    I would suspect that two universes with different Planck constants couldn't interact,
    if each universe had the same particles in it.This is because the energy levels of atoms in each universe would be different and so phenomenoa such as absorption of photons from one universe by electrons in atoms of another would not occur.
    Also, we would expect anisotropies in microwave background if other universes could contribute to our microwave background.However, a Planck constant that varies with time in our universe is a possibility, provided the other constants of nature vary too.
     
  13. Jul 31, 2004 #12
    Existence... then logic... then science?
     
  14. Jul 31, 2004 #13
    What about if their mathematical descriptions are askew, as is the prevailing paradigm? Their conclusions will be metaphysical in this stage of science; they do not agree in their cosmological point of view, as we have seen lately
    What is a mathematical experience? I thought mathematics were a tool invented by human mind to interpret and describe, in the case of physicists, the physical world

    Regards
    EP
     
  15. Jul 31, 2004 #14
    I agree with you. In that case we can think about a universe which its initial plank-like constant is in the size of our universe.
     
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