2 Pluto Moons in Need of Devilish Names P4 and P5 will soon be called something more underworld-y By Newser Editors and Wire Services Posted Feb 11, 2013 1:03 PM CST 21 comments Comments This file image provided by NASA on Feb. 22, 2006 from its Hubble Space Telescope shows Pluto and three of its five moons. ((AP Photo/NASA, File)) (Newser) – Want to name Pluto's two tiniest moons? Then you'll need to dig deep into mythology. Astronomers announced a contest today to name the two itty-bitty moons of Pluto discovered over the past two years. Three Pluto moons already have names associated with Hades and the underworld: Charon, the ferryman of Hades; the half-human, half-fish spirit Nix; and the multi-headed monster Hydra. The two unnamed moons need similarly shady references. Right now, they go by the bland titles of P4 and P5. They're no more than 15 to 20 miles across. Online voting will last two weeks. Twelve choices are available at plutorocks.com, and include the hero who slew Hydra, Hercules; and Styx, the river to the underworld. Write-in suggestions are welcomed.