The Pluto - a dwarf planet Had you asked anyone before 2006, which is the smallest planet in the solar system? An immediate reply would have been The Pluto . But now it is mere at the status of a dwarf planet. Now we can say The Pluto - a dwarf planet. The size of the dwarf planet is way smaller than the moon, about 66% of the diameter of the moon. Why and when Pluto lost the status of the planet? The planet is anything which is revolving around The Sun. As per this logic, Pluto should also be a planet as it used to be, but this is not the case anymore. Eris a dwarf planet was discovered in 2005, in the scattered orbital disc. The discovery of Eris led the scientist to think about the status of Pluto as a Planet. In 2006, Scientists formally defined the term Planet. Till 2006, there used to be nine planets in our solar system, but now there remains eight only. Pluto has lost the status of a planet in 2006 and got the status of a ...