Natural satellite been directly observed, have been called "moonlets". Small asteroid moons (natural satellites of asteroids), such as Dactyl, have also been called moonlets. The upper limit is also vague. Two orbiting bodies are sometimes described as a double planet rather than primary and satellite. Asteroids such as 90 Antiope are considered double asteroids, but they have not forced a clear definition of what constitutes a moon. Some authors consider the Pluto–Charon system to be a double (dwarf) planet. The most common dividing line on what is considered a moon rests upon whether the barycentre is below the surface of the larger
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