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
Giants (Greek mythology) Giants (Greek mythology) In Greek and Roman Mythology, the Giants, also called Gigantes ("jye-GAHN-tees" or "gee-GAHN-tees"; Greek: Γίγαντες, "Gígantes", Γίγας, "Gígas") were a race of great strength and aggression, though not necessarily of great size, known for the Gigantomachy (Gigantomachia), their battle with the Olympian gods. According to Hesiod, the Giants were the offspring of Gaia (Earth), born from the blood that fell when Uranus (Sky) was castrated by his Titan son Cronus. Archaic and Classical representations show Gigantes as man-sized hoplites (heavily armed ancient Greek foot soldiers) fully human in form. Later representations (after c. 380 BC) show Gigantes