In order to be classified as a planet, there are basically 3 criteria. (I'm a little fuzzy right now on the exact details, Brain-Dead Shann, so I'll just post the general concepts below.)
1) The body must be mostly spherical.
2) It must follow an elliptical orbit around the sun.
3) It must clear its path of other objects.
Now then. There are these things we like to call asteroids. Ones that have a
Ones that are in front of and behind Jupiter on its elliptical orbit path around the sun are called Trojans.
Soooo... interesting huh? Technically Jupiter could/should be declassified as a planet according that the above stated criteria. I'd like to see them try. Ha ha.
I especially like the logic in science: Because we said so.
*See? Wow. Brain dead. That would be really something... an asteroid with a diameter bigger than 1 AU. Yeah. Like that's really out there. Hell-o.
I initially put diameter and I wish Blooger had a strike-thru option. Nuts.
ETA again: Aha, figured out how to do a strike-through. Take that, Blooger!