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Homework Help: Hubble Constant Question!

  1. Apr 27, 2008 #1
    The Question

    One possible value for the hubble constant is 65Kms Mpc. Calculate in Mpc, the distance from Earth for agalaxy trallening at the speed of light, [itex]3.0\times10^{8}[/itex]




    [itex]H= 65Km s Mpc[/itex]

    First I will convert the constant to ms so that I have both in S.I. units.

    [itex]v=3\times10^8 ms[/itex]

    [itex]H= 6.5 \times10^4 ms Mpc[/itex]

    Now I will just plug these values in!

    [itex]\frac{3\times10^8}{6.5 \times10^4} = 4.6\times10^4 Mpc[/itex]

    State what this distance represents.


    This is the distance the galaxy is away from earth???

  2. jcsd
  3. Apr 28, 2008 #2
    Sorry, is this poorly set out? Is there something I have not included?
  4. Apr 28, 2008 #3
    You've made a slip in the final calculation (3x10^8)/(6.4x10^4) is not 4.6x10^4, that aside your method is correct.

    The significance of your answer is more than just the distance to a galaxy in this case because the recession velocity is the speed of light.

    Could the recession velocity be higher than this?
    Could we see any galaxies beyond this one?
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