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Science World for grades 6–10 brings science to life with fascinating feature articles and hands-on activities that reinforce science concepts and help students build test-taking and critical-thinking skills.
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Rocks Roll In from Outer Space!

Is there a space rock in your front yard?

By Barbara Bedway

Some kids have all the luck. On August 31, 1991 13-year-old Brodie Spaulding was hanging out in his front yard in Noblesville, Indiana. Suddenly, he heard a low-pitched whistle followed by a giant thud. "Pretty weird," he thought, and walked across the yard to investigate. There, he found a fist-sized stone lying on the grass.

"I thought the stone might always have been there," Brodie says. "But when I picked it up, it was . . . warm." Now he knew it was something really weird. Brodie mailed the rock to a lab at nearby Purdue University and waited eagerly for the results.

Chemical tests showed that Brodie's find was meteorite — a fragment of a space rock that had fallen to Earth.

Pet Space Rocks
Meteorites such as Brodie's, scientists say, hold important clues about our world. By studying them, scientists can "travel" far across space and way back in time: Many meteorites formed about the same time as our solar system — 4.6 billion years ago! Brodie's find was quite valuable . . .

And rare. Unless you have Brodie's luck, your chances of finding a pet rock from outer space are slim. Only about a dozen fall to Earth daily, and most of those splash down in the ocean. (Remember, two thirds of Earth is covered by water.) The ones that do reach dry land often look like ordinary rocks — especially if the meteorites lie around for years, exposed to the forces of weather.

Some people, at least, have hit the meteorite jackpot — or it has hit them. Take Wanda and Bob Donahue of Wethersfield, Connecticut. They were watching TV one night in 1982, when a grapefruit-sized meteorite crashed through their roof and come to rest under the dining room table. Incredibly it was the second time in just 11 years that a house in Wethersfield had been hit by a meteorite.

And of course, there's the mother of all meteorite tales. In 1954, Mrs. Hewlett Hodges of Sylacauga, Alabama, was actually struck by a meteorite. The nine-pound space rock crashed through her roof, bounced off a radio, and hit here as she lay on her couch. Luckily, Hodges walked away from the accident with nothing more than some bruises, a nifty space souvenir, and a one-of-a-kind story.

But don't head for Wethersfield or Sylacauga hoping for another hit. There's no more chance of another meteorite falling in those places than anywhere else in the world.

Instead, you could increase your chances of finding a space rock by heading to Antarctica. Geologists have found 13,000 meteorites on this icy continent. Before they started searching there, only 2,100 meteorite had been discovered worldwide.

Why so many so far south? The reason is simple: ice. Meteorites, you see, get trapped in the layer of ice that covers the huge Antarctic continent. As a result, "meteorites that fall in Antarctica are more easily preserved," says geologist Ursula B. Marvin. To recover these space rocks, Marvin cruises the continent on a snowmobile, looking for "stranding fields" — places where the ice has broken apart and exposed rocks within.

Scientists aren't the only ones trying to get their hands on meteorites. Some people actually make their living collecting and selling the rocks. A number of these collectors have offered to purchase Brodie's rock, now officially known as the "Noblesville Meteorite."

But Brodie isn't selling his find. He donated one piece to Purdue University, and plans to keep the rest. "Every day the scientists seems to learn new things about it," Brodie says. "I know how rare it is to find one. I don't ever want to give it up."


Meteorites: Where They Come from, How they Travel, What They Do When They Get Here

Most asteroids orbit the Sun in a path called the asteroid belt. The space rocks are thought to be material from the early solar system that never came together to form a planet.

Sometimes collisions between asteroids knock fragments into orbits that cross Earth's orbit. If the orbital timing is just right, the small fragments, called meteoroids, can come crashing through Earth's atmosphere.

As a meteoroid passes into denser layers of Earth's atmosphere, friction with air molecules cause the speeding body to glow and burn. The glowing trail is what we call a meteor.

Atmospheric friction consumes most meteoroids in under a second, but a few survive and strike the Earth. The fallen rocks are called meteorites.

The bigger the rock, the greater its kinetic energy (energy of motion) when it strikes Earth — and the greater the impact. A softball-sized meteorite poked a hole through a house in Wethersfield, Connecticut. A space rock around 500 times as large left Arizona with the vast tourist attraction called Meteor Crater. Some scientists think a meteorite eight kilometers across killed the dinosaurs. How? By blasting dust into the sky and blocking out the Sun.

 

September 1992.

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