Ruled by Hades, the god of the underworld, the infernal rivers of Greek mythology are often mentioned in ancient literature.

Whereas a moon usually orbits a planet, both Pluto and Charon orbit a point in space between them — their common center of mass. The other four moons in the system — Styx, Nix, Kerberos and ...

It might also have resulted in the formation of Pluto’s four other known moons — Nix, Styx, Kerberos and Hydra — which are tiny compared with Charon and were glimpsed when NASA’s New ...