Question

Why does not Mercury have an atmosphere?

Answer 1

Mercury is missing something called an atmosphere. You can think of an atmosphere as a protective shield of stuff (like gasses) that surrounds a planet. The reason that Mercury doesn't have anatmosphere is that it's just not massive enough-not big enough to have a gravity strong enough to hold gasses close to it.

Answer 2

mercury have not any atmosphere because it is very close to Sun and it is very hot in temperature