90482 Orcus Etruscan equivalent of the Roman Pluto, and later became an alternate name for Pluto. The surface of Orcus is relatively bright with albedo reaching 23%, grey in color and water-rich. The ice is predominantly in crystalline form, which may be related to past cryovolcanic activity. Other compounds like methane or ammonia may also be present. The existence of a satellite allowed astronomers to determine the mass of the system, which is approximately equal to that of the Saturnian moon Tethys. The ratio of masses of Orcus and Vanth is uncertain, possibly anywhere from 1:33 to 1:12. The diameter of Orcus
Ancient Mesopotamian underworld who is named Neti in Sumerian. The god Namtar acts as Ereshkigal's "sukkal", or divine attendant. The dying god Dumuzid spends half the year in the underworld, while, during the other half, his place is taken by his sister, the scribal goddess Geshtinanna, who records the names of the deceased. The underworld was also the abode of various demons, including the hideous child-devourer Lamashtu, the fearsome wind demon and protector god Pazuzu, and "galla", who dragged mortals to the underworld. The Sumerians had a large number of different names which they applied to the underworld, including "Arali", "Irkalla", "Kukku", "Ekur",