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Age of the Universe

  1. Jul 16, 2010 #1
    It is told that the universe is 13.4 billion years old according to present estimates.
    But as duration itself is a relative quantity what exactly is meant by this statement?
    Which frame of reference are we talking about when considering this figure and why?
     
    Last edited: Jul 16, 2010
  2. jcsd
  3. Jul 16, 2010 #2
    The age of the universe in a frame in rest relative to CMB
    In the other words, in rest to the local galaxies
    These frames have the longest proper time along their worldlines since the Big Bang
    All other observers (flying thru space) measure less time since the Big Bang,
     
  4. Jul 17, 2010 #3

    Chronos

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    Affirming dmitry, the universe appears to be no more than 13.7 billion years old as viewed from earth. We have an abundance of evidence supporting this assertion.
     
  5. Jul 18, 2010 #4
    Thanks for clarifying.
     
  6. Jul 18, 2010 #5
    That seems soooo "young" to me... I'm not doubting the validity of it - but it does seem like it's a short time for so much to have come about in the universe, I guess I just figured it'd be a lot older... hmm
     
  7. Jul 18, 2010 #6
    We live in a lucky time (for us) when the elements required for our form of life exist, and before the universe devolves into a state of diffuse radiation. It is the very youth of our universe that gives us a chance at all.
     
  8. Jul 19, 2010 #7
    The problem is that humans "are not fit" to think of such a long period of time. It' unnatural for us, since our lives only last decades. Think about the history of humanity. Look how much has changed in the last 4000 years or so. And that's nothing in 13.7 billions of years...
     
  9. Jul 21, 2010 #8
    Maybe the 13-14 billion year age should be limited to statements about our Hubble Bubble - the unobservable universe is by most estimates much greater in size than the Hubble distance; depending upon the model used to describe the evolution, basing the age of the universe upon data contained in the Hubble may someday need to be qualified. As several cosmologist have mused - things would be nice and tidy if H turned out to be 42.
     
  10. Jul 21, 2010 #9

    Chronos

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    We can never observe anything beyond our particle horizon. Whatever may [or may not] lay beyond that is scientifically irrelevant.
     
  11. Jul 21, 2010 #10
    I would generally agree from the standpoint of actual verification -- but not philosophically - and not from the perspective of modeling different universes, even though there can never be any certainty in these matters. For example, what is beyond the particle horizon is worth pondering if it leads to a plausible explanation of the observed changes in the expansion profile.
     
  12. Jul 22, 2010 #11

    Chronos

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    What philosophy would suffice as a substitute for observational evidence?
     
  13. Jul 24, 2010 #12
    The answer would be subjective - for some (call them the faithful) the entire framework of happiness and satisfaction depends upon the absense of observational evidence. For others, the lack of complete observational evidence leads to the joy of speculating upon different resolutions that may never be confirmed..
     
  14. Jul 26, 2010 #13
    There was a very interesting comparison which made it easier to understand large time span involved.
    So if we can imagine that the period from BB till today is 1 YEAR, than we started to exist as species 1 minute before the new year : )
     
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