Pluto Moons : Charon

Charon. Pluto Moons. Charon is Pluto's only known satellite. Charon is named for the mythological figure who ferried the dead across the River Acheron into Hades (the underworld). Charon was discovered in 1978 by Jim Christy. Prior to that it was thought that Pluto was much larger since the images of Charon and Pluto were blurred together.

Charon is unusual in that it is the largest moon with respect to its primary planet in the Solar System. Some prefer to think of Pluto-Charon as a double planet rather than a planet and a moon. Pluto and Charon are also unique in that not only does Charon rotate synchronously but Pluto does, too: they both keep the same face toward one another.

Charon's composition is unknown, but its low density indicates that it may be similar to Saturn's icy moon Rhea. Its surface seems to be covered with water ice. Interestingly, this is quite different from Pluto. It is doubtful that Charon has a significant atmosphere. Like the Earth's Moon, Charon may be the result of a collision between Pluto and another body.

Photo : NASA ESA HST

Earth

Mars

Jupiter

Saturn

Uranus

Neptune

Pluto

Eris