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
Lerna form decorative patterns on some pieces, or rolled scribed cylinders have been used to make banded patterns. Remarkably, banded patterns made with the self-same seal have been found at Lerna, Tiryns and Zygouries. The burning of the House of Tiles brought the Third Period at Lerna to a decisive close; a low round tumulus marked its undisturbed, apparently sacrosanct site. Lerna IV (Early Helladic III) marked a fresh start, not as a fortified seat of central authority this time, but as a small town, with houses of two and three rooms with walls of crude brick set upon stone foundations;