Rock Science: Meteors and Meteorites

A Multitude of History and Mystery

The 238-pound Juncal iron meteorite was found in Chile in 1866.

By Steve Voynick

The earliest meteorite with a documented place and date of fall came to Earth in France’s Alsace region in 1492. With a lack of understanding of meteors and meteorites at the time, townsfolk chained the two-foot-diameter piece of stone and iron to a tree to prevent it from escaping.

A century later, natives of Argentina’s Chaco region showed Spanish soldiers a metal boulder they had watched fall from the sky. The soldiers, who considered the tale impossible, instead believed that the boulder was part of an outcropped metal vein. They named the site Minero de Fierro (Iron Mine) and began digging toward what they were sure was a deposit of high-grade iron.

This three-inch fragment of the Sikhote-Alin iron meteorite came to Earth in a witnessed fall in
Russia in 1947.

Both accounts illustrate the mystery and misunderstanding that once surrounded meteors and meteorites. Today, we know that meteors are a solid matter from space that vaporizes and become incandescent upon entering the Earth’s atmosphere and that meteorites are the matter that survives atmospheric entry to reach the Earth’s surface.

With their thunderous noises, flashes of light, smoke trails, and sometimes violent impacts, meteors have always commanded attention. So, too, did meteorites with their great density, often high metal content, and unusual surface textures. Both became entwined in the lore, superstitions, and religions of various cultures.

Connecting Meteors and Meteorites

Yet until relatively recent times, no connection existed between meteors and meteorites. The idea of stone and metal falling from the sky defied all logic, as did the idea of extraterrestrial origin. Many early naturalists linked both meteors and meteorites to divine origin or the supernatural.

Even in the late 1700s, those seeking scientific explanations of meteorites discounted the possibility of extraterrestrial origin. Instead, the belief was that they were solidified masses of erupted magma that had traveled great distances, or material that had accreted from clouds of volcanic ash high in the atmosphere and fell to Earth.

German physicist Ernst Florens Friedrich Chladni was the first scientist to consider extraterrestrial origin seriously. But because Chladni had never personally witnessed a meteoric fall or interviewed those who had, his theory, published in 1794, was ridiculed.

The next year, a 56-pound meteorite nearly hit a farmer at Wold Newton, Yorkshire, England, and was found—reportedly still hot and smoking—in its impact crater. The wide-eyed farmer did not doubt that the meteor he had just seen and the meteorite lying at his feet were connected. But scientists disagreed, refusing to consider the word of a poorly educated farmer.

Witnessing a Spectacular Fall

Finally, in 1803, hundreds of onlookers at L’Aigle, Normandy, France,

This backlit slice is from the 2,028-pound Imilac iron-pallasite meteorite that was found in Chile in 1822; the translucent, yellow sections are grains of olivine.

witnessed a spectacular fall of several thousand meteorites. The French Academy of Sciences sent astronomer and physicist Jean-Baptiste Biot (for whom the biotite mineral group is named) to investigate. Biot studied dozens of meteorites, noting that their composition was unlike that of any volcanic or other terrestrial rock. He also interviewed dozens of individuals from all walks of life who had witnessed the fall.

After confirming that no volcanic activity had occurred anywhere near France on the day of the fall, Biot concluded that the well-witnessed meteor shower had delivered the meteorites and that both had an extraterrestrial origin.

After submitting his report to the French Academy of Sciences, Biot wrote articles for popular readership. His writings finally convinced both scientists and the public that meteors and meteorites were indeed linked. This revelation led to the founding of the science of meteoritics.

Until the 20th century, few meteorites from documented falls were recorded. But with public education and professional search efforts, the number of meteorite finds increased dramatically. Today, of 60,000 documented meteorite finds, some 1,500 are from witnessed falls.

The National Aeronautics and Space Administration estimates that 48.5 tons of meteoritic material falls to Earth every day, making it all the more surprising that the connection between meteors and meteorites remained a mystery for as long as it did.