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Unknown universal collapse

  1. Mar 6, 2009 #1
    Could it be that the universe is collapsing upon us without us yet knowing since the nearest star to us is about four light years away and therefore we have no present way of knowing what has happened during the last four years beyond that nearest star?
     
  2. jcsd
  3. Mar 6, 2009 #2

    marcus

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    There could be a huge hippopotamus only four light years from here and we wouldn't know because the light hasn't gotten here yet. It could be bigger than a hundred solar systems.

    Cosmology is a mathematical science driven by observational data. They look for the simplest model that gives a good fit to the data.
    There are now millions of data-points.
    The models give an amazingly close fit and they are astonishingly simple---you only need to plug in a half-dozen or so numbers and run the Friedmann equations (which are so compact they fit on a postit, I used to have them stuck on the side of my monitor.)

    It would take an far more complicated model, with arbitrary choices of many many additional parameters, to get one that would both on the one hand fit the observations seen so far, and on the other hand would predict the materialization of a giant hippo, or that would predict that collapse is now in progress and will exhibit itself to us in four years.

    Maybe the best answer, Onon, is that scientists make no claim to certain knowledge but they have some rather nice models that work reasonably well. Testing and improving their models keeps them busy. Certain knowledge is not the name of the game.
     
    Last edited: Mar 6, 2009
  4. Mar 6, 2009 #3
    Could it be you didn't just post that and I am hallucinating it? Welcome to the twilight zone.
     
  5. Mar 6, 2009 #4

    marcus

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    Hi Lubuntu,
    you and I posted the same minute, it was 1:32 PM my time.
    I think you gave a more appropriate answer somehow. The idea is funny.
    (Onon may even have been joking---that didn't occur to me.)
     
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