Chapter 8: Interplanetary Bodies

The Black Stone, surrounded by its silver frame and the black cloth kiswahon the Kaaba in Mecca. This stone is believed to be a meteorite.

Long ago, stones from the sky were a source of awe. Meteorites have been found buried with American Indian artifacts in Mexico and revered as a sacred possession by a tribe in Alaska. A stone worshipped in the Temple of Diana at Ephesus (one of the seven wonders of the ancient world) reportedly fell from the sky. The "Black Stone," enshrined around 600 A.D. or earlier in the sacred Muslim shrine in Mecca, is also believed to be a meteorite. They have even had a deep influence in history; in 1492, a meteorite fell at Ensisheim, France. Emperor Maximilian was in residence nearby, and he took the fall as a sign that he should go on a Crusade.

E. F. F. Chladni

Even when the origins of meteors are unknown, it is often clear that they are something unusual. These half-melted, often mostly metal rocks are typically significantly denser than their Earth-formed rocky cousins, and this high density means that meteors consistently outweigh same-size Earth cousins. It took a long time for a scientific explanation of these strange rocks to emerge. In the 1700s, many naturalists still felt that the idea of stones falling from the sky was no more than superstition. One scientist, however, decided to do a careful investigation rather than just dismiss this idea. In 1794, a German physicist named E.F.F. Chladni reported that the Ensisheim stone and other supposed celestial stones seemed similar to each other and different from normal terrestrial stones. He concluded that these "meteorites did indeed fall from the sky."

J. B. Biot

This conclusion was controversial, and many people still refused to accept a celestial origin for these stones. Upon hearing that a meteorite had fallen in Connecticut, Thomas Jefferson, himself an accomplished naturalist, is supposed to have joked, "It is easier to believe that Yankee professors would lie than that stones would fall from heaven." The French Academy — that bastion of rational thinking — dismissed meteorites as superstition. But when a meteorite exploded over a French town in 1803, pelting the area with stones, the Academy sent the noted physicist J.B. Biot to investigate. His report became one of the historically important documents of science. Biot constructed an irrefutable chain of evidence from eyewitness accounts, measurements of the 12 square kilometer area of impacts, and specimens of the meteorites themselves. This report was instrumental in establishing that stones do indeed fall from the sky.

The Peekskill Meteorite that hit a car in 1992.

Rocks in space may seem remote from human affairs, and generally, they are, but they can have a rather strong influence when they collide with the Earth. Although the Earth shows evidence of the destruction meteorite impacts can cause (in the form of impact crater scars), human encounters with falling meteorites are extremely rare. Nobody has been killed by a meteorite in recorded history, although a dog was killed in Nakhla, Egypt in 1911. In the last hundred years, a few people in the United States have experienced close encounters. In 1938, an Illinois woman heard a crash in her garage and found a meteorite lying on her car seat. Some years later, an Alabama woman was seriously injured by a ricocheting meteorite that hit her in the hip. A house in Wethersfield, Connecticut was hit in 1971, and then another house just a mile away was hit 11 years later! In 1991, two boys in Noblesville, Indiana heard a whistle and a thud and looked down to see a small 4-inch meteorite lying in a crater on the sidewalk. One year later, a woman found a 30-pound meteorite that had smashed through the trunk of her 1980 Chevy Malibu, fusing to the metal of the car. She was offered $69,000 for the wreck, which was far more than the car was worth before it was damaged! Don't let this summary worry you, though. Your chances of being hit by a meteorite are tiny — statistically speaking, your bathtub is far more dangerous.

Meteorite find in situ on desert pavement, Rub' al Khali, Saudi Arabia. 

Many big meteorites have been identified, but scientists are always looking for more. A fine rain of meteorites, ranging from the size of dust grains to pebbles, reaches the surface of the Earth all the time. They are difficult to notice on most terrain since they often look like regular terrestrial rocks, but they stand out on the blue-white surface of the Antarctic icepack. Scientists regularly travel there and sweep the surface with sticky rollers, to gather more of this valuable evidence from space. Another popular meteorite-hunting area is the Saharan desert in northwest Africa, which has revealed many interesting meteorites on its ever-changing sandy surface in the past few decades.