IAU definition of planet who had theorized on the existence of the large trans-Neptunian object Planet X, and Tombaugh been searching for Planet X when he found Pluto. Almost immediately after its discovery, however, astronomers questioned whether Pluto could be Planet X. Willy Ley wrote a column in 1956 titled "The Demotion of Pluto", stating that it "simply failed to live up to the advance publicity it received as 'Planet X' before its discovery. It has been a disappointment all along, for it did not turn out to be what one could reasonably have expected". In 1978, Pluto's moon Charon was discovered. By measuring
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