Why does Mercury have a thin layer of hydrogen and helium as an atmosphere?
A) Other elements move fast enough to escape Mercury's gravity.
B) Mercury temporarily traps solar wind particles.
C) These are outgassed by rocks in Mercury's crust.
D) These gases are released during impacts with comets.

Question

Quizplus · Accepted Answer

Mercury's weak gravitational field is unable to hold onto heavier gases like nitrogen and oxygen, but it is able to temporarily trap lighter gases like hydrogen and helium from the solar wind. This creates a thin and tenuous atmosphere around the planet.

Why Does Mercury Have a Thin Layer of Hydrogen and Helium