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Time from the origin of universe

  1. May 22, 2010 #1
    I have a question for the bright minds here. I have often wondered if spacetime has been constant thoughout the universe or if there are places where spacetime breaks down. One of these points I often imagine about is the very origin point of the Big Bang. Does anyone know of any papers addressing this question or have any input?

    Basically I am wondering if the age of the universe would be the same at all points in space, in particular from the very origin of the inflation. In my imagination this point seems a likely spot for the source of dark energy, and I often wonder if I could build a spaceship and fly to one of these points of inflation or dark energy would time exist there as we know it?
  2. jcsd
  3. May 22, 2010 #2
    Big Bang is not a point, it is EVERYWHERE. If Universe is infinite now, then it was infinite from the very beginning, and Big Bang was also infinite.

    The age of the Universe (13.7 b y) is maximum proper time - for all objects at rest to CMB - this is true for all objects we see. However, for, say, very high speed particle the proper time from the Big Bang can be much shorter.
  4. May 22, 2010 #3
    Yes I know everything was in that little space and there was no outside... but wouldn't there be a point in space today where the inflation started from?

    And as far as you know the only time dilation possible is under special relativity? Spacetime is consistent for all objects at rest no matter where they are? I would think if there are literally holes in spacetime inside of black holes then there time would not exist at all at least?

    Maybe someone can dumb this down for me on the infinite from the beginning part its hard to imagine that even for me lol. I was under the impression that the universe 1 trillionth of a second after the big bang would have been the size of a softball? Are there two different models I am thinking of here?

    Thank you very much dmitry and everyone, I don't know what I would do to satisfy my curiosity without this place!
  5. May 22, 2010 #4
    1 no, all points are equal.
    2 'only'? what do you mean? SR is a particular case of GR, so there is time dilation in GR as well
    3 Spacetime is consistent for all objects - at rest and not at rest. They all agree on if some event happened or not - they just dont agree on when and where.
    4 No. Except for singularities (and future theory will definitely get rid of them) everyhting is smooth, even inside the black holes
    5 This is about the radius of VISIBLE universe.
  6. May 22, 2010 #5
    I agree, thanks that makes perfect sense. If anyone has anything to add I'm all ears and taking notes :)

    So Gerald Schroeder is just a quack, I thought so I didn't find one published paper on that guy.
  7. May 22, 2010 #6


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    If I could add a little...

    1. Perhaps. In the early universe just after the big bang, the energy density of the universe could have taken on different values at different points in space. The inflaton is typically believed to have had chaotic initial conditions, so that in many places in the universe the conditions weren't right for inflation. However, in some patch of spacetime, the conditions were just right (spacetime was sufficiently smooth and the inflaton field dominated the local energy density). This patch inflated and became our entire observable universe (and probably then some). So, in a sense, inflation did occur in perhaps a small region of spacetime (not a point, though).

    2. Gravitational time dilation is unique to general relativity and is very important cosmologically. Time is dilated for observers in gravitational potential wells relative to those in free space.

    4. There's little use in talking about singularities. No physicists believes them to be physical. It is instead believed that quantum gravity becomes relevant before such a singularity forms physically.
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