Meteors are sometimes called "shooting stars" or "falling stars." They are not stars at all. They are lumps of metal or rock that are speeding around in space. When a meteor goes through the atmosphere of the earth, the meteor glows like a star and leaves a shining trail. Most meteors burn up 50 or 60 miles above the earth.
There are countless millions of meteors whirling through space. Outside of the earth's atmosphere they are cold and dark masses. When they enter the earth's atmosphere, the resistance of the atmosphere and the friction between the meteor's molecules and the molecules of the atmosphere cause the meteor to burn and glow. The trail of the meteor may be caused by glowing gases or molecules that are blown off the meteor as it burns and speeds through the air. The trail may be an optical illusion. The eye might retain a row of images of the meteor.
Some meteors are probably fragments of old comets. Sometimes there are "meteor showers" when a large number of meteors are seen at the same time. When this happens, the earth is probably passing through an ex-comet's orbit.
Once in a while a meteor does not burn up completely when it comes toward the earth. A meteorite is a meteor or a piece of a meteor that lands on the surface of the earth. Tiny pieces of meteors or meteoric dust are falling to the earth constantly. Meteorites are made up of iron, nickel, and other metals that are also found on earth. They have glossy outer crusts like cinders. As a meteor comes through the atmosphere, its surface becomes so hot that it burns and melts.
