Pluto’s largest moon, with vast canyons, water-ice terrain and a reddish polar region.
Charon is the largest of Pluto’s five known moons. At about half Pluto’s diameter, it is unusually large relative to its parent body. James Christy discovered Charon in 1978 while examining photographic plates of Pluto.
Pluto and Charon are mutually tidally locked: each keeps the same hemisphere facing the other. They complete an orbit around their common center of mass in about 6.4 Earth days.
New Horizons revealed broad plains, impact craters and a vast system of tectonic fractures. Much of Charon’s surface is dominated by water ice, while its northern polar region is distinctly reddish. Together, these features record a complex geological history.
NASA’s Eyes on the Solar System places Pluto in its wider solar system setting and lets you examine the Pluto–Charon system in three dimensions. Rotate the view, zoom in or out, and use the time controls to follow the modeled motion of the system.
NASA Eyes is an interactive visualization provided by NASA/JPL and loads from eyes.nasa.gov. If the embedded view is unavailable, use the full-screen link above.
Pluto has five known moons. Charon is by far the largest and forms a closely coupled pair with Pluto. Farther out, the four much smaller moons—Styx, Nix, Kerberos and Hydra—follow nearly circular orbits around the Pluto–Charon system.
Diagram is schematic; sizes and orbital distances are not to scale.
NASA Science provides mission background, observations and image collections; Wikipedia offers a broader reference overview with citations.
