Anonymous

It is a planet, just not a terrestrial or jovian planet, it is a dwarf planet

Anonymous

If you wish to call Pluto a planet then do so, it was demoted by a committee of astronomers.

Anonymous

Because it has not cleaned out its orbital neighborhood.

Anonymous

Pluto has the mass of 1/7th of our Moon. And our Moon is just a little over 1% of the mass of our Earth. So let's include fire crackers among our list of weapons of mass destruction, and include Pluto on our list of planets. What a great idea.

Anonymous

The Plutonians forgot to pay their dues to the International Astronomical Union, and so they got kicked out.

Anonymous

It didn't meet the new qualifications, and was relegated to "dwarf planet."