We knew Pluto had at least five moons. The surprise is that there aren’t more of them
Mark Showalter, who discovered two of Pluto’s moons as the mission was making its nine-year journey, said he truly expected to find many more, as did Alan Stern, the mission’s principal investigator.
Five may not be the final count, but if any more exist they were too small and too dim to see during New Horizons’ approach.
The moons are named for underworld figures in mythology.
The largest, often called a co-planet because of its size and closeness, is Charon. The others are Styx, Nix, Kerberos and Hydra.
