Christine Murakishi, Age 11, Of East Lansing, Mich... For her question:

Why is there no air around the moon?

The earth is a heavy planet with a mighty pull of gravity. This built in force hugs everything to the surface of the globe and even reaches up to hold down gases of the atmosphere. The moon is much sma7.1.er and much lighter than the earth. Its built in force of gravity is therefore much less than that of the earth.

The moon's gravity is only a sixth as powerful as the gravity of the earth. It is too weak to hold an atmosphere of filmy gases. If the moon ever had an atmosphere, the molecules of air escaped the pull of the lunar gravity and long ago drifted off into space.