how do they name the planets, anyway? The nomenclature of astronomical bodies has long been associated with Greek and Roman mythology. The Greeks named the wandering objects in the sky, planetes or wanderers, and identified them with their gods, Hermes, Aphrodite, Ares, Zeus and Cronus. The Romans, ever the inventive sort, renamed them after their own corresponding gods, Mercury, Venus, Mars, Jupiter and Saturn.
When Uranus was discovered in 1781, the decision was made to stick with Greek and Roman gods. Neptune followed in 1846, and Pluto in 1930. (For a nice human-interest story about the naming of Pluto, check out this interview with the woman who suggested its name when she was 12.)
As more objects and features on celestial objects have been discovered, the International Astronomical Union decided to expand the nomenclature to include characters from other world mythologies. My personal favorites are Uranus’ moons, named after the fairies and sprites of British folk stories, including ones that Shakespeare used in A Midsummer’s Night’s Dream.. Since Uranus has so many moons — 27 at last count — the IAU expanded the source names to include all the characters from A Midsummer’s Night’s Dream.
Check this wikipedia entry for more natural satellite names.