Charon: The Almost-Planet
(Dwarf) Planet: Pluto
Diameter: 1,206 km
Date of Discovery: 1978 (James W. Christy)
Most Badass Feature: The main moon of an inherently badass planet
Named after the mythological boatman who ferried doomed souls across the river Styx, Charon is Pluto’s largest moon. At roughly half the diameter of Pluto, the moon is so big that it basically forms a binary planet with its dwarfish host. In fact, the pair orbits a center of mass that lies between the two objects, rather than inside Pluto.
Though there aren’t any fantastic images of this moon-with-delusions-of-grandeur, there will be soon. In 2015, when NASA’s New Horizons probe swings by the system, we can expect to see Charon — and its underworldly friends — in detail.
Charon is joined by moons Nix and Hydra, as well as tiny runt satellites P4 and P5, still awaiting names. Could the two small moons soon be named Vulcan and Cerberus? If the results of a recent popular vote are any indication, it appears that the cast of characters will soon include a three-headed dog and the Roman god of lave and smoke.
Charon could still kick both their asses.
Images: 1) Lanthanum-138/Wikimedia, based on Mapping the surface of Pluto and Charon 2) Dr. R. Albrecht, ESA/ESO Space Telescope European Coordinating Facility; NASA