Pluto's smallest moons finally have names
More than two years after Pluto's fourth moon was discovered, it finally has an official name: Kerberos. The fifth moon, discovered last year, will be called Styx.
The moons were first discovered by SETI Institute scientists Mark Showalter. Normally, he would have the naming honors. But he decided to have a little fun with it. According to Wired, Showalter organized an international public voting campaign, Pluto Rocks!, which ran for two weeks in February.
As with the naming of all space objects, the rules stipulated that the name must derive from mythology. The public was invited to nominate names, as long as they were not yet used in astronomy and were related to Pluto (the Roman word for the Greek god Hades, ruler of the underworld).
More than 450,000 voters weighed in from around the world. Not everyone followed the rules, reports Wired: among the 30,000 write-in nominations were pop-culture pairs like Mickey and Minnie, and Stephen and Colbert.
When the votes were tallied, "Vulcan" came out far ahead of the competition. Vulcan is the Roman god of fire and volcanic fury, and the nephew of Pluto. It's also the name of Mr. Spock's home planet on "Star Trek."
William Shatner, the actor who played Captain Kirk on the television series, first tweeted the suggestion on February 12. It finished with 174,602 votes, according to Wired. The second-place finisher, Cerberus, came in with 99,432 votes. Styx was a close third at 87,858.
The IAU naming committee rejected Vulcan after determining that there are already too many objects named Vulcan in astronomy, including a class of asteroids. Cerberus also got the boot, because there is an asteroid by the same name. Showalter and his team suggested the Greek spelling, Kerberos, and submitted Styx to replace Vulcan.
In mythology, Kerberos refers to a three-headed dog that guards the gates of the underworld. Styx refers to a river separating the living from the dead. Pluto's largest and innermost moon is named Charon, the mythological boatsman who ferried souls across the river Styx. The other two moons are named Nix, goddess of the night, and Hydra, a monster who guarded one of the entrances to the underworld.
Discovered in July 2011 and July 2012, respectively, by a team using the Hubble space telescope, the two moons had thus far been known as P4 and P5.
