Chapter 33, Problem 23P

To determine

Distance of the galaxy from the Earth.

Answer to Problem 23P

The galaxy is $1.6\times {10}^8\text{ ly}$ away.

Explanation of Solution

Given:

Velocity of a galaxy is $3500\text{ km/s}$

Formula used:

Using Hubble’s law,

  $v=Hd$

Where,

H is the Hubble constant, v is the velocity and d is the distance

Calculation:

Distance of the galaxy showing red-shift is

  $\begin{array}{l}v=Hd\\ d=\frac{v}{H}\\ d\text{ =}\frac{3500\text{ km/s}}{22\text{ km/s/Mly}}=160\text{ Mly =1}\text{.6}\times {\text{10}}^8\text{ ly}\end{array}$

Conclusion:

Thus, the galaxy moving with the velocity of $3500\text{ km/s}$ is $1.6\times {10}^8\text{ ly}$ farther away.