Rotation.
The moon rotates completely on its axis (an imaginary line through its
north and south poles) only once during each trip around the earth. The moon
rotates from west to east, the same direction that it travels around the earth.
At its equator, the moon rotates at a speed of about 10 miles (16 kilometers)
per hour. When you look up at the moon, you always see the same side. The moon
is held in this position by gravitational forces. We know that the moon is
rotating because we can see only one side of it. If the moon did not rotate, we
would be able to see its entire surface.
All rights
Reserved: © World Book 2001
Paul
Gorenstein, "Moon," World Book Online Americas Edition,
http://www.aolsvc.worldbook.aol.com/wbol/wbPage/na/ar/co/370060, May 11, 2001.