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
Hydra the Revenge coaster comes from the story of Hercules in Greek Mythology. According to the story, Hercules had to perform twelve labours. After defeating the Nemean lion for the first labour, the second was to defeat the Hydra, a nine-headed creature with eight serpentine heads that would regrow each time they were cut off, including one that was immortal. Dorney Park altered the remainder of the story — after Hercules managed to defeat the Hydra initially, he buried the immortal head deep under a giant stone, with the intention of sealing it for all time. Many years later however, the head slowly