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 in popular culture stories, Percy's ADHD characteristics are explained as being caused by his Olympian blood, thus Riordan was "us[ing] Greek mythology as it has always been used: to explain something that is difficult to understand." In the opera within Girl Genius, the Heterodyne daughter who falls in love with the Storm King is Euphrosynia. The Amazon queen Hippolyta was used as the mother of Wonder Woman in the DC comic book line, At Niagara Falls, the Bridal Veil Falls had previously been called Iris Falls, and Goat Island had previously been called Iris Island as namesakes of the Greek goddess of the