Explain how earth's mass is related to its ability to have an atmosphere?

Answer 1

The Earth has an atmosphere because it has the gravity necessary to keep the gases from floating off into space. The more mass a planet has, the more gravity it has, and the more gravity it has, the thicker an atmosphere it can sustain.

Answer 2

Earth's mass directly impacts its gravitational force, which holds the planet's atmosphere in place. The stronger the gravity, the more likely the planet is to retain its atmosphere. Earth's mass is sufficient to maintain its atmosphere because the gravitational force is strong enough to hold gases close to the surface.