All else being equal, the more mass a planet has the thicker an atmosphere it will have.
True
False
The correct answer and explanation is:
Correct Answer: True
A planet with more mass generally has a thicker atmosphere, all else being equal. This is because a planet’s gravitational pull is directly related to its mass. A stronger gravitational force allows the planet to retain more atmospheric gases and hold onto them more effectively over long periods. The thicker the atmosphere, the more it contributes to pressure at the surface and overall climatic stability.
When a planet has low mass, its gravity may not be strong enough to prevent lighter gases like hydrogen and helium from escaping into space. Over time, this leads to a thinner atmosphere or none at all. For example, Mercury has a very small mass and almost no atmosphere. It cannot hold onto gases due to its weak gravity and proximity to the Sun, which increases gas molecule speed, causing them to escape more easily. On the other hand, Jupiter is a massive planet with a very thick atmosphere, composed mainly of hydrogen and helium. Its strong gravity helps it retain these light gases effectively.
Another example is Earth, which has sufficient mass to maintain a stable atmosphere with a mix of gases necessary for life, including oxygen and nitrogen. Mars, though similar in composition, has far less mass and a weaker gravitational field. As a result, it has a much thinner atmosphere, which affects its ability to support surface water and temperature regulation.
However, while mass is a major factor, it is not the only one. Distance from the Sun, temperature, magnetic field strength, and atmospheric composition also influence the thickness and longevity of a planet’s atmosphere. Still, if all other conditions are constant, a greater planetary mass tends to result in a thicker atmosphere due to stronger gravitational retention of gases.