Hydra (moon) the Hydra, the nine-headed serpent that battled Heracles in Greek mythology. The nine heads of Hydra are a reference to Pluto's tenure as the ninth planet; its initial, "H", refers to the Hubble Telescope, which discovered Hydra and, together with Nix, to the "New Horizons" mission whose safe passage was the motivation for taking the Hubble images. Hydra orbits the barycenter of the system in the same plane as Charon and Nix, at a distance of about 65,000 km. Its eccentricity of 0.0059 is small, but significantly non-zero, and the largest of those of Pluto's small moons (slightly larger than
Theban kings in Greek mythology no Theban leader is mentioned by Homer in the "Iliad". Theban kings in Greek mythology The dynastic history of Thebes in Greek mythology is crowded with a bewildering number of kings between the city's new foundation (by Cadmus) and the Trojan War (see Ogyges). This suggests several competing traditions, which mythographers were forced to reconcile. The first kings of the Boeotia region (before Cadmus and the flood of Deucalion) were Calydnus and Ogyges (Ogygos). The first king of the settlement that would become Thebes was Cadmus, after whom the city was originally called Cadmeia. It only became known as Thebes