Polly Plumer, age 9, of Costa Mesa, California, for her question:

What are asteroids?

Asteroids are baby planets, sometimes called planetoids or minor planets. There are thousands and thousands of them orbiting around the sun. They are made of solid materials and they come in all sorts of odd shaped chunks. About 20 asteroids are more than 100 miles wide and the biggest one known is 480 miles wide. But most of them are like boulders and bumpy blocks.

The spaces between most of the big planets are just right. But the space between Mars and Jupiter is so wide that there is room for another big planet. This is where most of the asteroids orbit around the sun like a swarm of golden bees. We call them minor planets because they travel in planet type orbits. But nobody knows why they are there.