Charon

Charon is Pluto's big moon. The two always show each other the same side – like two dancers holding hands.

Fact file

Charon orbits Pluto.

Charon is half the size of Pluto – the two circle a shared point between them and almost count as a double planet.
Pluto and Charon always show each other the same face: seen from Pluto, Charon hangs motionless in the sky.
Its reddish north pole (“Mordor Macula”) forms from gas that escapes from Pluto and freezes on Charon.

Charon has a diameter of 1,212 km. That is about 35% of the diameter of our Moon.

Charon orbits Pluto at an average distance of 19,591 km.

Charon orbits Pluto once every 6.4 days.

On Charon the average temperature is −220 °C.

After the ferryman who carries souls across the river into Pluto's underworld. Its discoverer James Christy was also thinking of his wife Charlene.

Discovered on 22 June 1978 by James Christy – as a “bump” on a photo of Pluto.

Probably formed when Pluto collided with another large body – much like our Moon.

No atmosphere.

Discovered in 1978 by James Christy. In 2015 New Horizons photographed a system of canyons four times as long as the Grand Canyon.

Around a third the size of our Moon.

Which moon is half the size of its dwarf planet?

Charon. Pluto and Charon orbit a shared point between them – almost a double planet.

The full quiz with points and badges is in the 3D model under “Explore”.