Pluto in size of Charon and Pluto has prompted some astronomers to call it a double dwarf planet. The system is also unusual among planetary systems in that each is tidally locked to the other, which means that Pluto and Charon always have the same hemisphere facing each other. From any position on either body, the other is always at the same position in the sky, or always obscured. This also means that the rotation period of each is equal to the time it takes the entire system to rotate around its barycenter. In 2007, observations by the Gemini Observatory of
The Adventures of Pluto Nash become stranded on the Moon and desires to earn some money by which to pay for transport back to Earth to Salt Lake City. Because her father "Nicky Sticks" was a friend of Pluto's, she seeks help from Pluto, offering her skills as a singer. Pluto instead gives her a job as a server at his club and allows her to remain inside to sleep after its nightly closure to the public. During the same night, Pluto is accosted thrice by Mogan (Joe Pantoliano) and Kelp (Victor Varnado), messengers of a mysterious entrepreneur called Rex Crater. They tell Pluto that