Why isn’t Pluto a planet anymore?

Video by C.G.P. Grey does a good job explaining why, in 2006, the International Astronomical Union demoted Pluto to dwarf planet status.


At the visible edge of the solar system, Pluto – official designation 134340 Pluto – has stirred controversy since the 2006 decision of the International Astronomical Union (IAU) to demote it to dwarf planet status. This little world – central to its own system of five known moons – is now the second-most-massive known dwarf planet in our solar system (after Eris) and the tenth-most-massive body observed directly orbiting the sun. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune are considered planets. Pluto isn’t in the same category anymore. Why not? The video below – created by C.G.P. Grey does a great job explaining it. Check out this video and decide for yourself. Was the IAU right in demoting Pluto to dwarf planet status?

source and credit a earthsky