Chapter 32, Problem 15RQ

Why does the Moon have no atmosphere?.

To determine

The reason for not having the atmosphere on Moon.

Answer to Problem 15RQ

The Moon has no atmosphere due to less gravity and low escape speed on Moon.

Explanation of Solution

The presence or absence of atmosphere depends on the escape speed for objects on that planet. The escape speed of the object depends on the gravitational pull of the planet. If the gravitational pull on a planet is very less, then the escape speed for the gasses on that planet becomes very less and gasses can easily escape from that planet.

The mass of the Moon is lesser than the gravity, it is one-sixth of gravity of Earth. The escape speed for Earth is $11.2\text{km}/\text{s}$ and escape speed for Moon is $2.83\text{km}/\text{s}$. The escape speed for the gasses on the Moon is very less, so the gasses can easily escape from the Moon.

Conclusion:

Therefore, the Moon has no atmosphere due to less gravity and low escape speed on Moon.