Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Hubble constant depend on expansion model?

  1. Oct 20, 2011 #1
    Does the measured value of the Hubble constant, H_0, depend on the details of the expansion model one uses?
     
  2. jcsd
  3. Oct 20, 2011 #2
    The Hubble Constant is not dimensionless (i.e., it will change depending on the units you are using), I know that slightly different values have been collected depending on the method used (all within error bars), I believe that the Cosmological Constant can be given a arbitrary value in Einsteins GR equations, although there is only a small range where the value would be reasonable.

    The reason I bring both up is that while the Hubble Constant is based on observation, the Cosmological Constant is based in the equations.
     
  4. Oct 21, 2011 #3

    Chalnoth

    User Avatar
    Science Advisor

    That depends somewhat upon how it is measured. If it is inferred from far-away observations, such as the Cosmic Microwave Background, then the answer is yes. But our most accurate measurements of [itex]H_0[/itex] are from nearby observations where the expansion rate hasn't changed enough for it to really matter what our model of the expansion is.
     
  5. Oct 21, 2011 #4

    Chalnoth

    User Avatar
    Science Advisor

    What? Why are you bringing this up? Because it sounds completely off-topic to me.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Hubble constant depend on expansion model?
  1. Hubble's Constant (Replies: 7)

  2. Hubble Constant (Replies: 1)

Loading...