What's The Difference Between An Asteroid And A Meteor?

The other day we dealt with an asteroid and a meteor. The 2012 DA14 asteroid zipped passed Earth today and a meteor exploded over in Russia. What the heck is the difference between an asteroid and a meteor? And a meteorite? And a meteoroid? Not too much, apparently!

An asteroid is a rocky object in space that's not as big as a planet and isn't a moon. There are millions of them, think the asteroid belt in space. A meteor is an asteroid that burns up as it enters the Earth's atmosphere, think shooting stars. A meteorite is a meteor that actually lands on the surface of Earth, think about Russia today.

As for a meteoroid? No one really knows. It's just a term to describe particles of asteroids that orbit around the sun. Just a smaller asteroid, pretty much. [Space]

Image: Don Davis via NASA