David Xoobemry,‑ age 10, of Safford,, Ariz. for his question:

What is a planetoid?

A planetoid is a junior‑sized planet. Our earth is a full sized planet. The earth and eight other planets travel around the sun in orderly fashion. A satellite is a heavenly body that travels around a planet. A satellite and its parent planet travel together around the sun. Our moon is a. satellite of the earth.

We might confuse our moon with a planetoid. But a planetoid is a very Independent body. It travels its own orbit around the sun. It refuses to be tied up with a planet.

Most planetoids of the Solar System travel between the orbits of Mars and Jupiter. We call this group of planetoids the asteroids. Not all of them are round like big planets. They come in all shapes and sides. If we saw one close up we might say, This is dust a lump of rock. Some are no bigger than pebbles. Some are hundreds of miles across.

A comet is a special kind of planetoid. For all its show, it is at most a few hundred miles across. Most of its time is spent chugging around a long narrow orbit which takes it far from the sun. During this time it is simply a collecton of matter going around the sun‑ a planetoid.