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Homework Help: How to find mean distance between galaxies from redshif?

  1. Jun 8, 2014 #1
    If we know the mean number density of galaxies in the universe, the redshift z and the Hubble constant. Is it possible to find the mean distance between galaxies at such redshift?

    The redshift gives a ratio of two distances between the same pair of bodies, at two different time due to the expansion of the universe. I don't understand how is this parameter related to the mean distance between galaxies. And how is it related to Hubble's law anyway?

    The question is attached. All 3 parts are confusing me...Please show some approaching ideas or solution, thank you!

    Attached Files:

  2. jcsd
  3. Jun 8, 2014 #2

    Simon Bridge

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    If you know the mean number density, what else do you need to know in order to work out the mean separation?
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