Astronomers discover a fifth moon orbiting Pluto

It may not be a planet, but Pluto's got moons to burn. Astronomers using the Hubble Space Telescope have spied the icy orb's fifth satellite. Everybody, say hello to S/2012 (134340), or "P5" for short.

Measuring somewhere between 6 and 15 miles in diameter, P5 may have to compete with P4 — which was discovered almost exactly one year ago — for the title of Pluto's smallest moon, but astronomers say it fits right in with the rest of the dwarf planet's system. "The moons form a series of neatly nested orbits," said team lead Mark Showalter in a statement released by Hubble, "a bit like Russian dolls." (Click here to see how P5 stacks up against the rest of Pluto's moons.)

Its size also means NASA will have to keep an eye out for P5 when its New Horizons spacecraft soars through the Pluto system in 2015. The Agency has been using Hubble to look for potential hazards to New Horizons in the months and years leading up to its historic flyby.

Astronomers discover a fifth moon orbiting Pluto

"The inventory of the Pluto system we're taking now with Hubble will help the New Horizons team design a safer trajectory for the spacecraft," said Southwest Research Institute's Alan Stern, the mission's principal investigator.

Seeing as we're already talking about planetary nomenclature today, I can't help but wonder what they'll wind up naming P4 and 5. (Nix, Charon and Hydra are all figures from Greek mythology with ties to Hades (aka Pluto), god of the Underworld.)

Read more over at HUBBLESITE.