Question

According to Hubble’s law, the redshift $(Z)$ of a receding galaxy and its distance $r$ from earth are related as

• A. $Z\propto r$
• B. $Z\propto 1/r$
• C. $Z\propto 1/r^2$
• D. $Z\propto r^{3/2}$

Answer 1

Answer: (A)

Hubble's law is the statement in physical cosmology that the red shift $(Z)$ in light coming from different galaxies is proportional to their distance $(r)$.
That is, $Z\propto r$
It is considered the first observational basis for the expanding space and today serves as one of the most often cited pieces of evidence in support of the Big Bang.