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Was there more galaxy clustering in early Universe?

  1. Mar 1, 2016 #1
    Has the expansion of the Universe caused less clustering? If the expanding Universe is causing volume of space to increase, to me it would make sense that clustering would be impacted as a result of this.
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  3. Mar 1, 2016 #2

    Vanadium 50

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    No, there's more clustering.
  4. Mar 1, 2016 #3


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    If there wasn't at least some expansion, then there'd be no clustering at all as the universe would just have recollapsed on itself.

    The rate of expansion does have an impact on clustering, but it's not terribly simple. In essence, in an expanding universe, an overdense region will collapse in on itself if it has enough mass relative to its size. If it's too spread out, it won't collapse. If it doesn't have enough mass, it won't collapse. With a faster rate of expansion, it needs more mass or a smaller size to collapse.

    So all other things being equal, in a universe that is expanding faster you'll get less massive galaxies that are further away from one another.
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