Contest to Mame Pluot's Moons February 12, 2013 - 11:22AM Pluto and three of it's five moons. Cape Canaveral: US astronomers have announced a contest to name Pluto's tiniest moons, but those who try will have to have a good knowledge of mythology. The two very small heavenly bodies have been discovered over the past two years. Pluto is the Roman equivalent of the Greek's Hades, lord of the underworld, and its three bigger moons have related mythological names: Charon, the ferryman of Hades; Nix for the night goddess; and the multi-headed monster Hydra. The two unnamed moons - up to 32 kilometres across - need similarly shady references because at the moment they go by the bland titles of P4 and P5. Online voting ends on February 25 at plutorocks.com.