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 comprehensive summary of Cicero's line of thought. In Ancient Roman times, a new Roman mythology was born through syncretization of numerous Greek and other foreign gods. This occurred because the Romans had little mythology of their own, and inheritance of the Greek mythological tradition caused the major Roman gods to adopt characteristics of their Greek equivalents. The gods Zeus and Jupiter are an example of this mythological overlap. In addition to the combination of the two mythological traditions, the association of the Romans with eastern religions led to further syncretizations. For instance, the cult of Sun was introduced in Rome