John Shaffer, age 12, of seneca Falls, N.Y., for his question

What is a planetoid?

Word tracing is a great game and very helpful when you want to know the meaning of a new word. The only equipment you need is a good dictionary  one that gives the origins from which our English words are coined. You also need the instincts of a detective, for the tracing of one word may lead you to investigate the backgrounds of many words.     WE can investigate the meaning of the word planetoid by dividing it into two parts. The word planet comes to us from a Latin word that came from a greek word which meant wanderer. This is because the planets of our solar system seem to wander against the background of fixed stars. If you have guessed that a planetoid is related to a planet, you are correct.     In chemistry, the word colloid means a glue like substance. In geometry, a  spheroid is an object somewhat like a sphere. A word part which modifies the meaning of a main word is called a suffix  and oid is a suffix coined from a Greek Word meaning like or resembling. A planetoid, then, is somewhat like a p1anet.  It is, in fact, exactly like a planet except in one feature. It is smaller, far smaller, than any of the nine planets of our solar system. But what our planetoids lack in size, they make up for in numbers. There are many thousands of these small bodies in our solar family. They may also be called asteroids, meaning star like, though planetoids are dead lumps of matter which shine only by the reflected glory of the sun. A planet is a lump of solid minerals, and so is/planetoid. A planet travels its orbit around the sun  this fact makes it different from a satellite, which travels in the company of a planet. A planetoid also travels its own orbit around the sun.     Thousands of planetoids orbit the sun like a swarm of golden bees, each traveling Its own orbit at its own speed. Most of the p1anetoids travel between the orbits of Mars and Jupiter. Some of  them come closer and some swing out farther from the sun, and at times a planetoid may come c1ose to the Earth. The largest of these small wanderers is less than 500 miles wide, and many of them are thought to be no bigger than pebbles.     Some astronomers suggest that the planetoids are parts of an unborn planet. Some suggest that they are parts of a p1anet which broke apart. Certain meteorites may be fallen planetoids, and these grounded space travelers may hold the secret of how this belt of small wanderers was formed.