Pan, the innermost of Saturn's known moons, is located within
the Encke Gap of Saturn's A-ring. It acts as a shepherd
satellite and is responsible for keeping the Encke Gap open. The
gap is a 325 km (200 mile) opening in Saturn's A ring. Pan
creates stripes, called "wakes," in the ring material on either
side of it. Since ring particles closer to Saturn than Pan move
faster in their orbits, these particles pass the moon and
receive a gravitational "kick" from Pan as they do. This kick
causes waves to develop in the gap and also throughout the ring,
extending hundreds of kilometers into the rings. These waves
intersect downstream to create the wakes, places where ring
material has bunched up in an orderly manner thanks to Pan's
gravitational kick. Pan, like Saturn's moon Atlas, has a
prominent equatorial ridge that gives it a distinctive flying
saucer shape. Pan was discovered by M.R. Showalter in 1990 using
images taken by the Voyager 2 spacecraft nine years earlier. How
Pan Got its Name: Moons of Saturn were