major moon · moon of the dwarf planet Pluto
Charon
Pluto's huge companion, so large that the two circle a point in space between them, both always showing each other the same face.
- Distance from Earth today
- 5.35 billion km35.73 AU · light: 4 h 57 min
- Distance from the Sun today
- 5.33 billion km35.64 AU
- As of
- 2 November 2026position from NASA/JPL orbital elements
Where it is today
Top view of the plane of Earth’s orbit, compressed distance scale. Open on the big map with the time slider →
Facts
- Diameter
- 1,212 km
- Mass
- 1,590 × 10¹⁸ kg
- Density
- 1,853 kg/m³
- Mean distance from the planet
- 19,600 km
- Orbital period
- 6.39 days
- Orbital eccentricity
- 0.0000
- Orbital inclination
- 0.0°
Source of the figures: JPL SSD – Planetary Satellites (public domain).
Discovery: 1978 – James W. Christy
Description
Charon is the largest of Pluto's five moons, about half Pluto's diameter, which makes the pair resemble a double dwarf planet. James Christy discovered it in 1978 at the US Naval Observatory, as a bump on photographs of Pluto. The two bodies orbit a shared centre of mass that lies outside Pluto, and both are tidally locked, permanently facing each other. New Horizons revealed a world of vast canyons and smooth plains, and a reddish polar region nicknamed Mordor Macula, thought to be stained by gases escaping from Pluto that freeze out and are altered by sunlight.