When they say the universe is expanding no-one told Pluto, due to some new classification it looks like we’re going to lose a planet. At first we thought we’d gain three or more planets but we could soon be teaching pupils at school about the eight not nine planets in our solar system. How did this come about? Well the classification for what is and isn’t a planet has long been debated and a recent proposal meant we would have three new planets called Ceres, Charon and UB313 (not yet officially named but nicknamed Xena). Originally the proposal was all about gravity and being a sperical shape.
However a new proposal centres on the orbit of a planet not crossing another planets orbit which pluto does (Neptune and Xena). It looks like Pluto, Ceres, Charon and Xena could all be called dwarf planets or even plutonians. Everyone seems in agreement that Pluto should never have been considered a planet, but the debate is what to do about it now that everyone has already accepted it as a planet.