Roger Ingle, age 15, of Asheville, N.C., for his question:

HOW DOES THE MOON'S GRAVITATIONAL PULL WORK?

Gravitation is the force of attraction that acts between all objects because of their mass  that is, the amount of material they are made of.

The moon's gravitational pull causes the ocean tides on earth.

The moon has little or no atmosphere and the force of gravity is six times weaker than it is on the surface of the earth. If a boy or girl weighed 60 pounds on earth, the weight on the moon would be only 10 pounds. Gravity is weaker on the moon because the moon's mass, or the amount of matter it contains, is about 81 times smaller than the earth's mass.

In 1968 scientists found that the force of gravity differs slightly from place to place on the moon. They believe the difference is caused by concentrations of mass. They use the term " mascons" to describe these areas but the cause of the mascons is not yet known.