Frontiers of Science:

Visitors from Outer Space—Meteorites

By Dr. Sherwood B. Idso

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    Have you ever seen an unusually heavy and smooth rock that looked like it was covered with small thumbprints? If so, you have probably gazed upon one of the oldest forms of solid material to be found in our solar system—an iron meteorite.

    Meteorites are objects from outer space, probably originating between Mars and Jupiter, that have fallen to the earth’s surface. Before such an object collides with the earth, however, it must pass through our atmosphere. When this happens the friction between its surface and the air causes it to become very hot; and it often begins to glow, giving off light and heat. At this stage the object is not yet a meteorite, but a meteor. This is what you and your friends have probably called a shooting star or falling star. Extremely large and bright meteors are also sometimes called fireballs.

    Meteorites are of great interest to scientists, both because of their age and their nonearthly origin. They are studied to learn more about how the earth and other planets may have been formed. We know that all of those creations were organized by Heavenly Father and Jesus; but since we do not know exactly how they were created, our ideas about it are called theories. Meteorites are so important to studies of this subject that two of the world’s meteorite experts have recently stated that “the next meteorite recovered may verify or cause revision of some accepted theories.”

    It is exciting to realize that even children can make a great contribution to science in this study. You may want to help by looking for a meteorite. If you find one, it will probably be named after your own town or county. But where should you look?

    Since meteorites fall at random all over the earth, one place is just as likely to be hiding a meteorite as any other. So you will want to look where they will be easiest to recognize. Relatively flat areas that are free of rocks, such as cultivated fields, dry lake beds, and sand dunes, are excellent places to begin. A recent expedition to the windswept ice fields of Antarctica found twenty-one specimens within just two hours after setting up camp! This area probably didn’t have any more meteorites on it than any other area on earth; they were just easier to find.

    If you think you’ve found a meteorite, how can you be sure? The best single test is to have your dad file or grind off a small corner of it. Iron meteorites will give an appearance of freshly cut iron, while stony meteorites will show specks of silver scattered about in the face of the cut. If your sample has either of these characteristics, then answer the following questions:




    1 Is the specimen heavy?


    2 Is the specimen solid and compact?


    3 Is the specimen attracted by a magnet?


    4 Is the specimen black or brown and rather smooth on the outside?


    Does your specimen pass the test? If you check yes to all of the questions, the object is very likely a meteorite. Sometimes part of the answers can be no and the object may still be a meteorite. If all of the answers are no, however, it probably is not.

    The final step you may want to take if you think you’ve found a meteorite is to send it (or at least a piece of it) to a special laboratory for further study. One excellent place to consider is the Center for Meteorite Studies at Arizona State University in Tempe, Arizona. This is the home of the world-famous Nininger Meteorite Collection of over 800 different specimens. The Director, Dr. Carleton B. Moore, will examine your find, estimate its value, and he might make an offer for its purchase.

    So if you have an interest in meteorites, look up to the heavens at night and down to the earth during the day. That special “visitor from outer space” that you may find could add a great deal to our knowledge of this wonderful universe in which we live.

    A slice through the Bagdad, Arizona, iron meteorite that has been polished to show its crosshatched internal structure. (Nininger Meteorite Award Poster.)

    A stony meteorite showing grainy interior and thin black crust. (Photo by Jeffrey J. Kurtzeman, Nininger Meteorite Award Poster.)

    A polished section of the Springwater Pallasite, a combination stony-iron meteorite. It is composed of silicate crystals embedded in a continuous network of nickel-iron. (Nininger Meteorite Award Poster.)

    A bird’s-eye view of Meteor Crater, Arizona. This great bowl-shaped depression is believed to have been formed by an iron meteorite about 100 feet in diameter that exploded upon impact with the earth. The crater formed is 600 feet deep and 3/4 mile across. Its lip rises 100 to 200 feet above the surrounding plain. (Photo by Peter L. Bloomer, courtesy of Meteor Crater Enterprises, Inc.)