The Moon (again)

[grasshopper]

Is there any atmosphere to enter around the Moon, and if so, is it easier to enter the Moon's atmosphere or to re-enter Earth's?

[COKOL]

Hello Grasshopper,

The Moon is surrounded by a high vacuum atmosphere.

The position of the Moon in its orbit determines the behaviour of the atmosphere.

For part of each month, when the Moon is on the sunward side of the Earth, atmospheric gases are impacted by the undisturbed solar wind; in other parts of the orbit, they move into and out of the Earth's magnetosphere. In addition, the low temperatures on the Moon's night side provide cold traps for condensable gases. Its natural lunar atmosphere, whose molecular density is 14 orders of magnitude less than that of the Earth, (meaning that it would probably be easier to penertrate the moon's atmosphere than to re-enter the earth's.)

The main gases naturally present in the moon's atmosphere are neon, hydrogen, helium and argon.