A meteor is produced when a bit of rock or dust from outer space enters the earth's atmosphere at a high speed.  The friction between this material and the molecules in the atmosphere causes intense heat to build up and makes the material glow -- producing the streak of light people call a "shooting star."

A meteor shower is a period when we see an unusually large number of meteors.  These periods come when we pass through the dust left behind by a comet and they are named for the constellation from which they seem to originate.  (Of course, the stars in a constellation are much much farther than the meteors.)  For instance, the Perseid meteor shower in April occurs when the Earth passes through the dust left by Comet Swift-Tuttle.

Usually, the piece of material is small (dust to marble-sized), and it burns up before it reaches the ground.  If it is big enough, however, part of it may make it to the ground:  we call this a meteorite.

Very large meteorites that hit the ground at high speeds will actually heat up and melt the ground, splashing up blobs of molten earth.  As these blobs fly through the air, they harden.  These hardened bits of melted earth are called tektites; they then often break when they hit the ground again, producing shards such as the one pictured below.  This tektite was found in Thailand; I bought it from a tektite dealer at a Science conference. (It was only $10 or so:  you can get them from Bethany Sciences). Notice that this particular tektite is concave, which means it is likely to have been a part of a hollow sphere of molten material .  One edge is glassy, indicating that it broke when it hit; the other is pitted, indicating that this break occurred while in mid air, as the pitting occurs when it runs into dust in the atmosphere.  The outside of the curve is much more pitted than the inside as well.  All this is inference, of course, based on careful observation.

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©2001 Jeff Goodman

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