-If the above shown spiral galaxy is 150 million ly away, how fast is it receding
A)32 km/s
B)320 km/s
C)3220 km/s
D)-320 km/s

Question

-If the above shown spiral galaxy is 150 million ly away, how fast is it receding 
A)32 km/s 
B)320 km/s 
C)3220 km/s 
D)-320 km/s

Quizplus · Accepted Answer

The galaxy's recession speed can be estimated using Hubble's Law, which states that the velocity (v) at which a galaxy is moving away from us is directly proportional to its distance (d) from us. Hubble's Law is given by v = H0 * d, where H0 is the Hubble constant. The value of H0 is approximately 70 kilometers per second per megaparsec (km/s/Mpc). Since 1 megaparsec (Mpc) is equal to about 3.26 million light-years (ly), a galaxy 150 million ly away is about 46 Mpc away (150 million ly / 3.26 million ly/Mpc). Multiplying this distance by the Hubble constant gives a recession speed of approximately 3220 km/s (70 km/s/Mpc * 46 Mpc).

-If the Above Shown Spiral Galaxy Is 150 Million Ly