If you live in a typical urban environment, chances are your night sky is tainted by the inescapable glow of mall parking lights, industries, too many houses, and uncountable street lights. The black of night is more of a grayish hue, and seeing stars can be reason to rejoice.
But deep in the backcountry, where the midnight sky is as dark as a crow's belly, the dome overhead comes alive with an almost unfathomable number of stellar sights, the most
exciting being shooting stars. Who hasn't sat tentside and watched in awe and fascination as glowing streamers zipped across the darkened heavens? If you're like me, you've also wondered if the forces of gravity are strong enough to pull one of them out of the sky and send it earthward.
The answer is yes, and it happens more frequently than you might imagine. In fact, you may literally stumble across space debris on the trail and not realize it.
Shooting stars are actually meteors-chunks of space debris-burning through Earth's atmosphere at speeds up to nine times faster than the space shuttle (see "Star Struck" for more about meteor showers). More often than not, meteors are incinerated into oblivion before they come anywhere near us. But if it does make it all the way to the Earth's surface, the "shooting star" becomes a meteorite.
The chances of finding such an unearthly remnant are not as astronomical as you might think. More than 8,000 new meteorites reach Earth's land mass every year. Multiply that by thousands of years, and you've got several tons of out-of-the-ordinary rocks lying around.
Since meteorites fall in a nearly perfect random pattern over the Earth, they can be anywhere. Trails that skirt farmland offer miles of potential, since farmers usually place rocks unearthed during plowing along field edges. Or if you happen across an old abandoned homestead, look for piles of rocks or stone walls.
Knowing what to look for is the key to finding a bona fide meteorite. It will look different from the other rocks, since its origins and wear-and-tear were different. The surface will have a smooth "cooked," or glazed, appearance, possibly with small pock marks. The color is often black or dark gray, though older meteorites may be a rust brown. Shape is usually irregular, not spherical.
Most meteorites are known as iron or stony-iron meteorites because of their high iron content, which also makes them easier to identify. Others are mostly rock and are simply called stony meteorites, though they still contain a little iron. This iron is always mixed with some nickel, a combination that doesn't occur on Earth.
Thanks to these particular combinations, a small magnet is all you need for your first step in
field-identifying a potential piece of outer space. First, search for an odd-looking stone, one out of place with its surroundings. Pick it up. If it feels heavier than you expected for its size, that's a good sign. If its surface appears to have been fired in a kiln, like pottery, that's even better. Next, suspend a magnet on a string near the rock. If there's iron in the rock, you'll immediately feel or see the magnet sway toward the rock as it's attracted to the iron.
Scratch the rock with a knife blade and catch the scrapings on a piece of paper. An outer surface that is much darker than the inside of the rock may indicate that the rock has a "fusion crust" from its fiery fall. Next, move the magnet under the paper and see if the scrapings respond.
If the specimen clearly passes all these tests, make a note of the exact location. If you're really eager to get to the bottom of the rock's origins, you can contact the physics or geology department of a nearby university or natural history museum, which can subject your rock to more sophisticated tests. Or check with a specialist program, such as the Center for Meteorite Studies at Arizona State University in Tempe. The Web page of the Meteoritical Society (www.uark.edu/studorg/
metsoc/index1.htm) is chock full of links and information about meteorites and research.
As always, be respectful of private property and public lands. That potential meteorite might belong to someone else. The National Park Service specifically prohibits removal of any natural object, including meteorites, and though the Forest Service does allow meteorite collecting, it may soon require a free "treasure hunting" permit to do so.
Although the findings of amateur collectors have advanced meteorite research, most specimens gathered wind up as weird-looking rocks on a mantel. When deciding what to do with your treasure, consider leaving it where you found it. Then you can believe that you just might have touched a relic from the beginning of time itself.
Tom Weist is a freelance writer living in east Tennessee. Besides enjoying amateur astronomy, he writes an outdoors sports column for two newspapers.