When I began research for this week's topic, my first quest was learning the difference between an asteroid and a comet. Here's what I discovered. Comets (dirty snowballs) are primarily composed of ice and dust. As they near the sun, the heat melts the comet's ices and releases the dust particles we view as the comet's tail. Asteroids (minor planets) are large rocks ranging in size from a few feet to several hundred miles across. Ready to learn more?
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Asteroids that are on a collision course with Earth are called meteoroids. When a meteoroid strikes our atmosphere at high velocity, friction causes this chunk of space matter to incinerate in a streak of light known as a meteor. If the meteoroid does not burn up completely, what's left strikes Earth's surface and is called a meteorite."
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In the asteroid belt between Jupiter and Mars, there are twenty-six asteroids larger than 124 miles in diameter, traveling along with hundreds of thousands of smaller asteroids. This page, created by amateur astronomer Bill Arnett, nicely catalogs what is known (and unknown) about these minor planets. Links to great NASA photographs are at the bottom of the page.
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"WARNING ! AUTHORIZED PERSONNEL ONLY! DEPARTMENT OF EXTRATERRESTRIAL PHENOMENA. COMPUTER ACCESS RESTRICTED TO DEP AGENTS WITH LEVEL 4 SECURITY CLEARANCE." Are you ready for your assignment as an investigator with the Department of Extraterrestrial Phenomena? In order to solve the four real-life impact incidents in this National Geographic simulation, you'll need to know a bit of asteroid science and history.
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By Barbara J. Feldman. Originally written on Apr 25, 2001. Last Modified on Jan 04, 2008.
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Honorable Mentions
The following links are either new discoveries or sites that didn't make it into my newspaper column because of space constraints. Enjoy!
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