What is the redshift of a galaxy which lies at a distance of 350 Mpc, assuming that the Hubble constant is...?

Question

H0 = 73 km s–1 Mpc-1?

Assume that the speed of light is

c = 3.0 × 105 km s–1 and give your answer to an accuracy of 2 significant figures

REDSHIFT = ??

Answer 1

using the non relativistic Hubble law, we have:

v=H0 D = 2.56x10^4 km/s

we find z from:

v= c z -> z=v/c=0.086 which justifies the use of the non relativistic expression