Hubble Constant Question!

  • Thread starter _Mayday_
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  • #1
_Mayday_
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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]

Attempt

[itex]v=Hd[/itex]

[itex]v=3\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]

Question
State what this distance represents.

Answer

This is the distance the galaxy is away from earth?

_Mayday_
 

Answers and Replies

  • #2
_Mayday_
807
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Sorry, is this poorly set out? Is there something I have not included?
 
  • #3
apelling
70
0
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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