Natural satellite achieved hydrostatic equilibrium, and Uranus has five. It has been suggested that some satellites may potentially harbour life. Among the identified dwarf planets, Ceres has no known natural satellites. Pluto has the relatively large natural satellite Charon and four smaller natural satellites; Styx, Nix, Kerberos, and Hydra. Haumea has two natural satellites, and Eris and Makemake have one each. The Pluto–Charon system is unusual in that the center of mass lies in open space between the two, a characteristic sometimes associated with a double-planet system. The seven largest natural satellites in the Solar System (those bigger than 2,500 km across)
The Adventures of Pluto Nash Dina suggests that the initials are in fact "MZM", having been seen upside-down by Mona Zimmer. Pluto searches for "MZM" and discovers a criminal called Michael Zoroaster Marucci (Alec Baldwin). Pluto suspects that Michael Marucci and Rex Crater are one and the same. Abruptly, he is contacted by his mother, who tells him that Rowland has been killed by a fellow police officer and the hideout is attacked by Rex Crater's agents. A chase ensues and the heroes escape, but their car is damaged and explodes, causing them to be presumed dead by the agents. They manage to get out