Kathy Weaver, age 11, of Muncie, Indiana for her question:

What happens to falling stars?

We see them as bright little sparks arching down through the sky    and most of them disappear in a moment. Sometimes one of these so called falling stars is extra bright and lasts long enough to plummet down to the ground. But don't expect it to look like a spectacular heavenly body. If you do manage to find it, chances are you might mistake it for an ordinary pebble among the ordinary stones of the earth. Only an expert could tell that the fallen star is actually a grounded traveler from outer space.

Those flashy falling stars are called meteors and astronomers estimate that 200,000 of them crash into our bulky planet every day of the year. These are the ones that are showy enough to be visible and most of them are no bigger than grains of sand. Many more dusty little meteors plunge through the earth's atmosphere, too small to blaze visible trails through the air. And we collide with only those meteors that happen to be space traveling through our section of the solar system.

Obviously the spaceways swarm with meteors. Some are mountainous, others are only as big as boulders and pebbles. Out in space they reach speeds of 26 miles per second. They may be unused planetary material or fragments shattered from larger bodies. In any case they belong to the solar system and those that come close enough are captured by the earth's gravity. The earth's motion makes them curve down through the atmosphere. Friction with the air molecules generates heat up to 4,000 degrees Fahrenheit.

Falling meteors glow and start to burn about 65 miles above the earth. At 35 miles, the dusty midgets are .consumed to ashes. Those weighing a few pounds or more survive the fall, though their skins are crusted with burns and some break apart as they fall. The survivors either crash onto the ground or splash into the sea.

This ends their space traveling days forever. These grounded meteors become earth bound meteorites and add their weight to the earth's 6.6 sextillion tons. It is estimated that the meteors that strike during an average day could add 1,000 tons to the weight of the world. Even the ashes from tiny meteors eventually sift down to the land and sea. Falling stars and other showy meteors become meteorites and then become part of the earth.

The sizable meteors that survive the fall carry amazing news items from outer space. Stony meteorites are similar to the earth's rocky minerals. Others are metallic chunks, mostly iron and nickel. The most interesting ones are called carbonaceous chondrites. Recently, some of these were found to contain amino acids, those strange chemicals used to build the complex molecules of living cells. But this fabulous story provides the answer to quite a different question.