One small moon has been found orbiting within the main rings (A, B, C). This moon, named Pan, orbits in the Encke Gap, near the outer edge of the A ring. Pan sweeps the gap clear of the smaller ring particles, thereby maintaining the gap. If Pan disappeared, so would the Encke Gap. Scientists suspect that other moons are lurking in the Saturn system, creating some of the other gaps in the main rings. Cassini may find these moons during its mission. Collisions between ring particles occur frequently in the main rings, and ring particles can easily be knocked into a new orbit by these collisions. If a moon collided with a large enough ring particle, the moon could be fractured or lost within existing ring material. In either case, it might no longer be identifiable as a separate moon. Saturn’s E, F, and G rings orbit outside the main rings. The outermost ring — the E ring — is the most extended. Enceladus moves through the E ring, and it may have ice volcanoes that are responsible for producing the ring’s tiny particles of ice. The G ring is so thin that it would probably disappear quickly if it did not have several small moons orbiting within it and producing particles. No one has yet seen these probable G ring moons — perhaps the Cassini spacecraft will!