Illustration of the Sun eclipsed by Pluto as seen from the icy surface of its moon Charon. Pluto and Charon are icy bodies orbiting each other in the Kuiper Belt on the outer edges of the Solar System. The Sun is some 6 billion kilometres distant. Charon is around half the size of Pluto, which has a diameter of 2,300 kilometres. Pluto was reclassified from a planet in 2006, and is now considered a dwarf planet.