20 Things You Didn't Know About... Meteors

X-ray slaps, the Tears of St. Lawrence, and the fiddly asteroid/meteoroid/meteor/meteorite distinction.

By LeeAundra Temescu|Tuesday, August 01, 2006

1 The most famous and spectacular meteor shower, the annual Perseids, will peak on August 12th. Sadly, the show will be a virtual washout this year because a near-full moon will flood the sky with light. Consider this list your consolation prize.

2 The Perseids are also called the "Tears of Saint Lawrence" after a martyred Christian deacon whom the Romans burned to death on an outdoor iron stove in A.D. 258. Before dying, he was said to have cried out: "I am already roasted on one side. If thou wouldst have me well cooked, it is time to turn me on the other."

3 Technically, a meteor (from the Greek meteoron, meaning "phenomenon in the sky") is merely the streak of light we see trailing a meteoroid. A meteoroid is any interplanetary object bigger than a speck of dust and smaller than an asteroid.

4 Once it hits Earth, a meteoroid suffers an identity crisis and becomes a meteorite.

5 Chase that, Superman: Perseid meteoroids enter the atmosphere at approximately 130,000 miles per hour.

6 Meteorites contain the oldest known rocks in the solar system, as well as pre-solar grains, minerals that formed around other stars perhaps billions of years before our solar system was born.

7 To protect it from the estimated 100,000 meteoroids that will slam into it during its expected 20-year life span, the International Space Station is covered with a foot-thick blanket of Kevlar, the material used to make bulletproof vests.

8 Each day, up to 4 billion meteoroids fall to Earth.

9 Don't worry. Most of them are minuscule in size.

10 Meteorite impacts have been blamed for hundreds of injuries, but only one has been verified by scientists. In 1954, Annie Hodges of Sylacauga, Alabama, was struck by an eight-pound meteorite that crashed though her roof and bounced off a radio into her hip while she was napping.

11 A study published in 1985 in the journal Nature calculated the rate of impacts to humans as .0055 per year, or one event every 180 years. Thanks to Annie Hodges, odds are that the rest of us are safe through the end of this century.

12 Maybe that's why President Clinton canceled Clementine II, a spacecraft designed to defend Earth against incoming meteoroids, asteroids, and comets, a.k.a. Near Earth Objects. Or the probe may have fallen prey to the giggle factor, the tendency of government officials to snicker at the perils posed by flying rocks.

13 One way of deflecting a Near Earth Object is to explode a nuclear device in its vicinity. The resulting radiation pulse would vaporize the object's surface; as the vapor streamed away, it would deliver a thrust that could throw the body off course. This push is known as an X-ray slap.

14 A 30-foot-wide meteoroid that struck the atmosphere over Antarctica in 2004 left 2 million pounds of dust in its wake—enough to seed rain clouds and affect the climate on the other side of the planet.

15 To communicate over long distances, NATO and the National Weather Service still bounce radio signals off the ionized trails left by meteors when they enter Earth's atmosphere.

16 If you find a meteorite, the Nomenclature Committee of the Meteoritical Society demands that you donate 20 percent or 20 grams, whichever is smaller, to a laboratory for future research. You can sell the rest.

17 Unless you found it in South Africa, where all meteorites are protected under the National Heritage Law and must be surrendered to the nearest authorities.

18 Of the more than 24,000 meteorites known to have landed on Earth, only 34 are thought to have originated on Mars. Most of these have been found in Antarctica and North Africa because they are easy to spot on sand dunes and ice.

19 Martian meteorites can sell for $500 a gram. Space rocks fetch just $2 a gram.

20 To buy one, try eBay, which often lists more than 1,000 meteorites for auction. Or call Steven Spielberg, one of the most avid collectors (along with Sheik Saud bin Mohammed al-Thani of Qatar.

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