Hubble Constant Question!

1. Apr 27, 2008

_Mayday_

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, $3.0\times10^{8}$

Attempt

$v=Hd$

$v=3\times10^8$

$H= 65Km s Mpc$

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

$v=3\times10^8 ms$

$H= 6.5 \times10^4 ms Mpc$

Now I will just plug these values in!

$\frac{3\times10^8}{6.5 \times10^4} = 4.6\times10^4 Mpc$

Question
State what this distance represents.

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

_Mayday_

2. Apr 28, 2008

_Mayday_

Sorry, is this poorly set out? Is there something I have not included?

3. Apr 28, 2008

apelling

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?