Pan is the innermost named moon of Saturn. It is a small, ravioli-shaped moon approximately 35 kilometres across and 23 km wide that orbits within the Encke Gap in Saturn's A Ring. Pan is a ring shepherd and is responsible for keeping the Encke Gap free of ring particles. It is sometimes described as having the appearance of a walnut.
Closeup of the Encke Gap, showing the central ringlet that is coincident with Pan's orbit.
Cassini image showing Pan orbiting in the Encke Gap.
Pan in the center of the image, occupying the Encke Gap in Saturn's rings. Its walnut-like shape is clearly visible.
Stretched (4x) images, processed in various ways.
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body. Natural satellites are colloquially referred to as moons, a derivation from the Moon of Earth.
Size comparison of Earth and the Moon
Artist impression of Rhea's proposed rings