Linda Potts age 11, of Manheim, Penna., for her question:

Where are the asteroids?

The asteroids circle the sun with the planets. In fact they are also called minor planets and planetoids, which means little planets. Most of them occupy a wide belt between the orbits of Mars and Jupiter. The orbits of the inner planets Mercury, Venus, Earth and Mars are fairly evenly spaced. They form rough circles with less than 50 million miles between. The space between the orbits of Mars and Jupiter is over 340 million miles wide. This vacant lot in the Solar System is the home of most of the asteroids.

So far, over 1500 asteroids have been discovered and named. The first four were named Ceres, Pallas, Juno and Vesta, grand names from the Greek myths. When this list of names ran out, asteroids were named for characters in the works of Shakespeare and Wagner. A few with unusual orbits were given masculine names and one group was named for the heroes of Troy.

The search for asteroids began in 1801 with the discovery of Ceres. Cores is a lump of rock some 488 miles wide. Pallas, discovered in 1802, is some 304 miles wide. Juno, discovered in 1804, is 118 miles wide and Vesta, found in 1807 is 248 miles wide. These are the biggest of the asteroids. Many others are 50 miles wide or less and still more are a mile wide or less.

Each asteroid has its own orbit which it repeats and repeats around the sun. Most of these orbits are rough circles safely between the orbits of Mars and Jupiter. Some of the orbits are ellipses, or ovals. These ellipses may swoop inside the orbits of Earth and Venus or swing out beyond Jupiter near the orbit of Saturn.

These renegade asteroids are interesting because they can come very close to the earth. No asteroid crosses or intersects the earth's orbit. It passes above or below the path of the earth, Chances are, when this happens, the earth is far away on some other point along its orbit. But, once in a great while, the earth happens to be right, there when an asteroid reaches the closest point to our orbit.

In 1931, the asteroid Eros came within 16 million miles of the earth. This is much closer than any planet ever comes to us. Eros is famous as the little body who helped the astronomers figure the exact distance of the earth from the sun. This distance of 93,005,000 miles is the astronomical unit so useful in figuring the dimensions of the Solar System.

In February of 1938, the asteroid Hermes came within 460,000 miles. Closer than half a million miles. This little fellow can come even closer. It can come within 220,000 miles of the earth and this is closer than the moon. Since 1937 it has circled the sun almost exactly 31 times, said Brian Marsden, of the Minor Planet Center in Cambridge, Mass. Its orbits can change appreciably over time due to gravitational influences of the planets, noted Michael Nolan, an Arecibo Observatory astronomer. Two other asteroids, Adonis and Apollo may come almost as close. These three visitors are each estimated to be less than a mile wide.

On the other hand, an asteroid named Hidalgo can swing way out beyond Jupiter almost to the orbit of Saturn. These renegades, however, are exceptions. Most of the teeming asteroids travel in circles around the vacant lot between Mars and Jupiter.