Is That Unusual Rock A Meteorite?

+ Von Del Chamberlain +

December 9, 1998

A spectacular fireball burns through the sky illuminating the night like day and disappears behind a stand of trees. With the memory of this blazing object in mind, someone finds an unusually heavy stone off in the direction where the fireball disappeared. A meteorite. Right? Probably not.

Fireballs can be so impressive that they lead to lots of misunderstandings. People who are more than one hundred miles away are the ones who think they know right where the object came to earth. Actually meteorites almost always cease their luminous flight while still at least a dozen miles above the ground, falling from that point as dark objects. People who are actually in the fall area see the fireball disappear overhead and within minutes hear explosive sounds, sonic booms caused by the movement of the object through the air. Then, if they are actually in the fall area, they might see and hear fragments striking the ground.

Many are the stories that persist about people seeing a brilliant fireball, going out to where it came to the horizon and finding what they believed to be a meteorite. A town in Michigan's upper peninsula, "Star Siding," got its name from just such an event, and some people in the community think they have the meteorite that caused the fireball. What they have is a large ingot of slag from an iron works that was once active in the region. Another example of a fireball misinterpretation ended up as an episode in "Unsolved Mysteries." In 1966 a great fireball was seen over southern Canada and several midwestern states. Some of us gathered lots of data about this impressive event. There is no question about its nature--a classic fireball. Yet those producing the TV series would rather believe that it was a UFO that came to earth on that September evening. Don't try to change their minds with scientific data. It makes a much better story to build it into a case of aliens visiting Earth.

I have been interested in meteorites for most of my professional career. I have studied both the fireball phenomenon and meteorites themselves. Certainly a meteorite is one of the most interesting objects we can hold in our hands and wonder about, a scientific treasure to be sure. From studying the chemistry and structure of meteorites we learn about the composition and history of the solar system. Except for cosmic rays that come zapping through us all the time, meteorites were the only material objects we could take into the laboratory and study in great detail. Then, with space technology capabilities, we became able to recover small amounts of samples from the Moon. We also learned that a few meteorites have actually come from planets, having been blasted off them with the impact of asteroids and comets. With improving space technologies we will increase our samples from other planets, their satellites, and from asteroids by going out to these bodies and collecting directly from them. Still, meteorites that come down to earth from space will remain among our most interesting scientific collections.

Because of my interest in meteorites, over the years people have brought many unusual stones they thought to be meteorites seeking my opinion about their identity. I think I have looked at hundreds of them. Some have been kept for many years as door-stops. A few larger ones have places of honor in gardens. They have even been turned into headstones marking graves of those who found them. So far, only one object brought to my attention for identification turned out to be a meteorite. This one had been found about the turn of the century by a six-year old boy while helping his father clear a field of stones in preparation for farming. He picked up a lump of metal and showed it to his father who said, "throw it away and get busy--it's just like all the others." But the boy kept the object and in 1965, now in his sixties, brought the small piece of metal to me. It was a beautiful iron meteorite, the only piece known from this particular meteorite fall.

So what are all the other things people have shown me? I call them "meteor-wrongs." In every case I wish they had been meteorites, and it has always been difficult to tell people that they were not--I greatly dislike disappointing people. Every one of the objects has been interesting: glass or metal slag, basalt, various metallic ores, even an occasional fossil. I really do not want to discourage people from reporting unusual findings to science. After all, a meteorite is usually identified because someone cared enough to take the object to a geologist, chemist, mineral scientist or someone else who might be able to identify it. Checking out meteor-wrongs is just part of the business of collecting meteorites for scientific analysis.

When people are out looking around they find all sorts of interesting things. It is often a great mystery how some things get deposited where they are found. Usually this is because someone earlier found the same object to be interesting, carried it around for awhile, then finally tiring of the burden, tossed it away. They might toss it anywhere; along the roadside or in some remote place. This has been happening from earliest times. Interesting natural specimens including fossils, crystals, chunks of ore, and even meteorites have been found in archaeological ruins where they were carried by the people who once lived there.

True meteorites are most valuable to science. Each new one adds important information to help us better understand our world, the solar system and the grand universe. So, if you have something you believe might be a meteorite, take it to someone who can identify it, and if it really is a meteorite, make it available for scientific study. If it turns out to be a meteor-wrong, keep it as a personal treasure in your storehouse of experiences.