In a recent decision, the members of the International Astronomical Union's (IAU), have reclassified what is considered a planet. In doing this, they reduced Pluto and 50 other celestial bodies that have recently been discovered to the status of a dwarf planet. In Pluto's case he receives dual classification as a dwarf and icy planet.
In one swift move they have saved millions of school children from having to learn 50+ more planets in our solar sytem. I say Hooraaaay for Astronomers! In an effort to help said students, I am listing below the new criteria for a celestial body to be considered a planet:
- it must be in circular (not elliptical) orbit around the Sun
- it must be large enough that it takes on a nearly round shape
- it has cleared its orbit of other objects
One more argument used by scientists to demote Pluto: if it were any closer to the sun, it would simply be a chunk of ice as the sun's heat would melt and evaporate the ice.
So there you have it folks, even the biggest of guys gets demoted.