Question

The Hubble constant, $H_{0}$, is the ratio of the recessional velocity of a galaxy to its distance. The Hubble constant is estimated to be 70 km/sec per million parsecs of distance. (One parsec is equal to 3.26 light years.) Based on this ratio, how many billions of light years away would a galaxy be if it had a recessional velocity of 300,000 km/sec?

Answer 1

14 billion light years away

Step-by-step explanation:

v = Recessional velocity = 70km/s/million parsec

D = Proper distance

Hubble constant

`70\ km/s=3260000\ ly\\\Rightarrow 1\ km/s=(3260000)/(70)\ ly`

From Hubble's law we have the relation

`v=H_0D\\\Rightarrow D=(v)/(H_0)\\\Rightarrow D=(3260000)/(70)* 300000}\\\Rightarrow D=13971428571.42857\ ly`

The distance in light years of the galaxy is 14 billion light years away