Moonday: Helene

From The Planetary Society comes this image of Saturn and its moon, Helene. (Several other magnificent color pictures of Saturnian moons at the link.) You can tell at glance it's a fairly small moon; it's irregularly shaped and has enormous relief compared to its size. Larger bodies with more mass are more strongly effected by gravity and pull themselves into more spherical shapes. A quick check of Wikipedia gives its mean diameter as 17.6 km (11 miles). Though this moon was only discovered in 1980, it was not from a Voyager flyby, but from ground-based observations.