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
Greek mythology and various other mythological scenes appear, supplementing the existing literary evidence. Greek mythology has had an extensive influence on the culture, arts, and literature of Western civilization and remains part of Western heritage and language. Poets and artists from ancient times to the present have derived inspiration from Greek mythology and have discovered contemporary significance and relevance in the themes. Greek mythology is known today primarily from Greek literature and representations on visual media dating from the Geometric period from to onward. In fact, literary and archaeological sources integrate, sometimes mutually supportive and sometimes in conflict; however, in many cases,