Today is the fifth anniversary of the demotion of Pluto from "planet" to "dwarf planet." PLUTO 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 … Continue reading Happy demotion day, Pluto – Pluto and other Trans-Neptunian Dwarf Planets in animation, games and TV