MCQ Detailed View

A planet’s atmosphere is held in place primarily by the force of gravity. Gravity is the natural attraction that pulls objects with mass towards each other. In the case of a planet, its gravity pulls the gases of the atmosphere toward the planet’s surface, preventing them from drifting off into space.

While other factors like pressure, charge, and heat affect the atmosphere’s behavior, they do not hold it in place. Atmospheric pressure is the force exerted by the weight of air above, but it results from gravity pulling the gases downward. The charge of a planetary body does not play a significant role in holding the atmosphere, and heat generally causes gases to move faster, potentially helping them escape if the gravity is not strong enough.

Gravity ensures that gas molecules remain close to the planet. Without sufficient gravity, a planet cannot hold onto its atmosphere, which is why smaller celestial bodies like the Moon or Mercury have very thin or no atmosphere.

Understanding gravity’s role in maintaining an atmosphere is important in physics and planetary science. It explains why some planets have thick atmospheres rich in gases, while others have almost none. This concept is fundamental to studying Earth’s environment, weather, and how life is supported.