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, Illinois Lerna, Illinois Lerna is a village in Coles County, Illinois, United States. The population was 286 at the 2010 census. It is part of the Charleston–Mattoon Micropolitan Statistical Area. Thomas Lincoln, father of President Abraham Lincoln, spent the later part of his life on a homestead a few miles away, preserved today as the Lincoln Log Cabin State Historic Site. Thomas Lincoln and his second wife Sarah Bush Lincoln are buried in Shiloh Cemetery south of town. Lerna is located at (39.417943, -88.288957). According to the 2010 census, Lerna has a total area of , all land. As of the