One of the smaller moons in the Saturn system is Daphnis, a little 8 km (5 mile) irregular satellite which orbits the gas giant within the outer rings of the planet (although I guess really the famous rings themselves are composed of innumerable “moonlets”). Daphnis, which has the irregular shape of a potato, orbits Saturn in a 42-kilometer (26 mile) wide belt in the rings—the Keeler Gap. The moon is responsible for clearing this narrow track, and it is felt that by studying this interaction we may learn about accretion and the enigmatic happenings of the early solar system (when more things looked like Saturn). Here is a picture from NASA’s Cassini probe which was released yesterday which shows little Daphnis producing waves in the Keeler belt. What a remarkable image! I need to post more Cassini pictures here. They fill the heart with wonder and give us a chance to get off-planet for a little breather.