Pluto’s companion, Charon, is almost too large to be a moon (Image: Keck Telescope) Pluto is an alien world in almost all respects, but in one way it resembles Earth: it has a large, close companion.

The study, carried out by Mark R. Showalter of the SETI Institute and Doug Hamilton based at the University of Maryland, reveals that at least two of Pluto’s moons do not have an orderly rotation on ...

Planets, moons and other celestial bodies are named according to rules established by the International Astronomical Union (IAU). Pluto did not have any rules for naming surface features because, ...