Pluto's moon Charon was discovered in 1978 and was thought to be the only satellite of the dwarf planet. But in 2005, the Hubble Space Telescope turned its lens on Pluto to reveal two more satellites, dubbed Nix and Hydra. "Nix and Hydra are roughly 5,000 times fainter than Pluto and are about two to three times farther from Pluto than its large moon," according to astronomers. In this photo, Charon is seen to the lower immediate right of Pluto. Nix and Hydra are also to the right, with Hydra being the farthest away.