What is the redshift of a galaxy which lies at a distance of 50 mpc, asssuming that the hubble constant is H_0 = 67 km s^-1 Mpc^-1?
assume that the speed of light is c=3.0x10^5 Km s^-1 please answer to an accuracy of 2 sig figs. Thankyou.
First get the speed of the galaxy away from the observer by multiplyiing distance by the Hubble constant. This will give you the velocity in km/s.
V = 50 Mpc *(67 km/s)/Mpc = 3350 km/s
The RELATIVE redshift is
(deltaL)/L = V/c
The absolute redshift, delta L, depends upon the wavelength you are observing.