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I A basic question about units

  1. Dec 31, 2016 #1
    Hi
    This is a really basic question about units. I have been reading a paper about supernova rates and the units are given as:

    SN rate per yr MPC^3. h_70^3 (10^ -4)

    Could someone tell me what the h subscript 70 to the power of 3 means?

    Thanks
     
  2. jcsd
  3. Dec 31, 2016 #2

    Orodruin

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    It is a dimensionless number denoting the current rate of expansion. It is equal to the current hubble rate divided by 70 km/s/Mpc.
     
  4. Dec 31, 2016 #3
    To the power of 3?
     
  5. Dec 31, 2016 #4
  6. Jan 1, 2017 #5

    Chronos

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    A dimension is just another reference frame
     
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