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Exploring Meteorite Mysteries: Slides 1-9
Part 1. Introduction(may be used with Lesson 1)Meteorites are rocks that fall to the Earth from space. Meteorites, large and small, have been hitting our planet for billions of years and they still hit today. They are collected and intensely studied by scientists. Meteorites are samples from remote parts of our solar system, with histories that extend back billions of years. |
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1. Noblesville fallIt was nearly dusk on the evening of August 31, 1991, in the small town of Noblesville, Indiana. Two boys, 13 year old Brodie Spaulding and 9 year old Brian Kinzie, had just finished riding bikes and were standing talking on Brodie's lawn. Suddenly they heard a low-pitched whistling sound and Brian saw an object spinning through the air past Brodie. The object, which looked like a rock, landed with a thud on the ground near them. The boys picked up the rock and found it slightly warm. They looked around, but couldn't find anyone who might have thrown it.Several days later a scientist from Purdue University confirmed that the rock was really a meteorite. The boys let scientists have a small portion of their meteorite for scientific studies. In 1996, though they have been offered several thousand dollars for it, the boys still owned their rock from outer space. (Photo by Michael Lipschutz, used with permission) |
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2. Noblesville meteoriteThis is Brian and Brodie's rock, now known as the Noblesville meteorite. It is a typical stony meteorite, gray inside and covered with a dark crust. About 30,000 small meteorites like Noblesville fall on Earth each year, but only a few are found. In the 200 years since people have understood that meteorites are from space, only about 800 meteorites have been found right after they fell. (Photo by Cecilia Satterwhite, NASA JSC photo S91-50055) |
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3. Painting of the Sikhote-Alin fireballLarge meteorite falls are rare, about one every ten or twenty years over the whole Earth. One of the most spectacular occurred in 1947, in the Sikhote-Alin mountains of eastern Russia. There were only a few small villages and farms in the dense forests of Sikhote-Alin. Mid-morning on February 12, the calm was shattered by a bright meteor, visible for more than 300 kilometers, that streaked across the sky, shedding sparks and leaving a trail of swirling smoke. An eyewitness painted this impression of the meteor. After it streaked over the horizon, great explosions roared and echoed from the hills, so loud they were heard 100 kilometers away. Some airplane pilots saw the meteor and soon after found where the meteorites fell. (NASA JSC photo S79-29470) |
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4. Sikhote-Alin forestClearings in the thick forest were blasted open by the impact. There were 106 craters and holes in the forest where the meteorites had landed. Explorers found many pieces of iron meteorite in the forest, and 150 kg of iron in the largest crater, which was 26 meters across and 6 meters deep. The force of the impact had thrown stones farther than a kilometer. Some of the meteorites were embedded in trees! Explorers found over 23 tons of iron meteorites from this fall. The Sikhote-Alin meteorite was probably a piece broken off an asteroid. It must have been larger before it hit the Earth, because some of it vaporized in the atmosphere and on impact. (Photo by Kirov expedition, courtesy of the Smithsonian Institution) |
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5. Sikhote-Alin meteoriteThis is one fragment of the Sikhote-Alin meteorite. It is about 15 cm across. The photograph shows the original meteorite surface, melted into thumb-print shapes during its flight through our atmosphere. (Photo by Carl Allen, NASA JSC photo S94-43472) |
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6. Meteor Crater, ArizonaLarger meteorites are extremely rare, but make enormous craters when they hit the Earth. Meteor Crater in Arizona is over one kilometer across and 150 meters deep. It was formed about 50,000 years ago when a large iron meteorite hit the Earth. Scientists estimate that the meteorite weighed one million tons. However, the meteorite was shattered and vaporized by the force of its impact and only small pieces survived. (NASA JSC photo S78-33855) |
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7. Desert collectionSmall meteorites fall to Earth each year, but most aren't seen because they hit in the ocean or in unpopulated areas. Many meteorites have been found in deserts, where the heat and dryness have kept them from rusting away. When meteorites are discovered, they are called finds. Over 2,000 meteorite finds have been made around the world. Some of these meteorites were on Earth for hundreds of thousands of years before being found. (Photo by Michael Zolensky, NASA JSC photo S94-44547) |
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8. Meteorite in AntarcticaThe best collecting place in the world is Antarctica, where meteorites fell on the ice and were preserved in it. Here, scientists traveling on snowmobiles have found a meteorite, and have taken pictures to document their find. Since 1969 scientists have found thousands of meteorites in Antarctica. (Photo by John Annexstad, NASA JSC photo S80-35602) |
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9. Meteorite curationMeteorites collected by U.S. expeditions in Antarctica are sent to this clean lab at NASA's Johnson Space Center in Houston, Texas. There they are described, classified, and distributed to researchers around the world for study. (NASA JSC photo S96-13391) |
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