This week the International Astronomical Union (made famous in the eyes of the public for reclassifying Pluto as a Dwarf Planet) gave Pluto’s newly discovered moons their official names. Previously known as “P4” and “P5”, these tiny moons are now named Kerberos and Styx respectively. The names were the result of an online naming contest where people could suggest and vote on their favorite names. You may have seen news a few months ago that one of the moons was named Vulcan (after the Roman god of fire, but also the native world of Dr. Spock from Star Trek). Vulcan won the naming contest, but in the end the official decision was up to the IAU. Here at the planetarium we were a little bummed about the decision to cast out the vote for Vulcan as a name..
The IAU wanted to keep with the Pluto/Underworld theme and Vulcan just didn’t fit in with that! Pluto was the Roman god of the Underworld and it’s largest moon was named Charon, after the ferryman who transported souls across the river Styx. In 2005 two more moons were discovered. They were named Nix and Hydra. Nix (originally spelled Nyx) was the mother of Charon, and Hydra was a many-headed serpent that guarded the underworld. Kerberos (spelled this way to distinguish it from the asteroid already named Cerberus) was the three headed dog that guarded the mythical entrance to the underworld. Styx of course is the mythical river that souls must cross in order to enter into the underworld.
The new moons are very small (Styx is barely visible in this Hubble image). These moons aren’t much bigger than downtown Baton Rouge!