Today is the fifth anniversary of the demotion of Pluto from "planet" to "dwarf planet."
Pluto was first discovered in 1930. Part of the reason it was accepted as a planet was due to the fact that despite some behavior not fitting a proper planet it was assumed to be larger than Mercury unti l1978, when its moon, Charon, was discovered, revealing that the mass of Pluto was much smaller than had been thought... roughly a twentieth the mass of Mercury. Two more orbiting objects, Nix and Hydra, were discovered in 2005. S/2011 P 1 (aka P4) was discovered in 2011.
Reaction to Pluto's re-designation was controversial, especially among young nerds who failed to see how going from the smallest planet in the solar system to largest known object in the Kuiper Belt could be viewed as a positive move. The New Mexico House of Representatives and Illinois State Senate passed ridiculous anti-scientific resolutions to continue recognizing Pluto as a planet.
Of the Trans-Neptunian Dwarf Objects, Pluto remains the most popular, if not the largest. In animation it's appeared in Cowboy Bebop, Futurama, Galaxy Express 999, Roughnecks -Starship Troopers Chronicles, Space Battleship Yamato, Science Ninja Team Gatchaman, Super Dimensional Fortress Macross and The Magic School Bus.
PLUTO IN VIDEO AND COMPUTER GAMES
In games, Pluto has been depicted in Battlezone 2, Descent, Epch Star, Gyruss, Lenny Loosejocks in Space, Mass Effect, Star Control II and Starsiege.
PLUTO ON TV
According to my strenuous research, Pluto has never made it to the big screen - perhaps the result of our collective subconscious's acceptance of its diminutive stature. A better and more natural fit has been TV, where it's appeared in the Doctor Who episode “The Sun Makers”, Earth - Final Conflict, Space Odyssey - Voyage To The Planets, the Space Patrol episode “The Fires of Mercury” and X-Bomber.
The remaining known Trans-Neptunian Dwarf Planets are Eris, Haumea, Makemake, Orcus, Quaoar, Sedna and Varuna. If it's any consolation to the cognitive dissonance-suffering "Pluto is a Planet" crowd, none of them have shown up in any of these forms of entertainment. Nonetheless, each is interesting if not crying out for an appearance in science-fiction narratives. Eris is bigger than Pluto and yet no one is pushing any state resolutions to recognize it as a planet. Haumea (fka Santa) seems to be and ellipsoid. Makemake is unique among known KBOs for its lack of a satellite. Orcus seems to have a large amount of water. Quaoar is named after a Tongva god.