Konny Loewig, age 12, of St, Catharines, Ontario for his question:

Were the asteroids really once a planet?

There is a lot of evidence to suggest that the little planetoids between Mars and Jupiter were once a planet. On the other hand, some experts suggest that the asteroids are building blocks for a new planet. One theory suggests that they are the debris of a planet whichs for some reason, shattered to pieces. The other theory suggests the opposite  that the asteroids are the makings of a planet yet unborn,

We are not yet certain how our Solar System was formed and in this matter, too, we have a number of theories, One theory of the origin of the Solar System suggests that the big planets were made from countless small planets or planetoids, These bits of debris once drifted halter skelter around the sun. Big ones and little ones collided and clung together forming baby planets. The baby planets gathered more and more debris until they became as big as they are now.

If this were so, the asteroids between Mars and Jupiter md.ght be a roving flock of planetoids which have not yet got together to make a sizable planet. However, there seems no indication that the little bodies are in the process of forming bigger bodies. In fact, the weight of the evidence is on the side of the theory which suggests that the asteroids were once a planet.

True, the bulk of the asteroids does not equal even a small planet. But many have been lost. Ceres, the biggest, is less than 500 miles wide. Pallas is about 300 miles wide and Vesta is 248 miles wide, Most of the rest of them are maybe less than 50 miles wide. It is estimated that the total volume of all the asteroids is less than one twentieth the volume of the moon. At the present time, then, there are not enough asteroids to make a planet,

Most of the asteroid orbits are between the orbits of Mars and Jupiter, but some have orbits that take them farther afield, Once in a while an asteroid comes very close to the earth. If 3.t reaches the earth's atmosphere, it comes crashing down as a blazing meteor. If its weight is more than ten pounds, the little traveler may reach the ground without burning to ashes, It then becomes a meteorite, And, since a fallen meteorite may have come from the asteroids, it may tell us something about them,

Some meteorites are made of stony materials, very much like the minerals of the earth's crust. Others are hard metals, like the materials in the core of the earth. This suggests that the asteroids are fragments of a planet formed like our own, with the heavier materials inside and the lighter stony minerals in the crust, We do not know this for sure, of course. Nor do we know how or when the planet, if there was a planet, shattered to pieces,