Eh if Pluto had life like Earth it would be called a planet.
Also we need actual names for the sun and moon.
dj1200 posted...
Trump is going to claim Pluto as a planet and harvest its resources.
He's going to strip mine all the plutonium.
Accrovideogames posted...
In order for an object to be a planet, it must follow three criteria. 1. It must orbit a star. 2. It must be big enough to have enough gravity to force it into a spherical shape. 3. It must be big enough that its gravity has cleared away any other objects of a similar size near its orbit around the star. The third one was added when astronomers realized we potentially had hundreds of planets in our system. They had to demote Pluto or promote more objects to planets and regularly add more to the list whenever new ones were discovered and confirmed. They came up with the third criteria to resolve the issue. In addition, they created a new category for objects that follow the first two criteria but not the third one. This new category is dwarf planet, which is what Pluto is now. The other objects officially recognized as dwarf planets by most, if not all, astronomers are Ceres, Eris, Haumea, Makemake, Quaoar, Sedna, Orcus, Gonggong, and Salacia.
It was Eris's discovery as the "tenth planet" that sparked the discussion about what defines a planet. Ceres was long considered a planet before it was demoted to asteroid. Astronomers realized that when Pluto was later discovered, classifying it as a planet was an arbitrary decision. If Pluto was a planet, then Ceres should never have been demoted. There was no clear definition, so they had to make one and stick with it.
There's a major difference between demoting something from a planet to an asteroid and demoting something from a planet to dwarf planet.