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Rather than searching on "comet, meteor, and asteroid" and sifting through an astronomical number of results, we shot over to the Comets, Meteors, and Asteroids category in the Yahoo! Directory. We were seeking a web site with a comprehensible yet thorough explanation of these other-worldy objects. Among the "Most Popular" site listings, we spotted the web home of NASA's Near-Earth Object Program. The intriguing name sounded right on-topic, so we clicked over for a look around. The FAQ page proved to be just what we were looking for -- some straightforward space facts. In the simplest of terms, here's what we learned... Asteroids and comets are both classified as near-Earth objects. Asteroids are made of rock or metal and are thought to have been created in the warmer inner solar system. Comets are composed of ice, rock, and organic (carbon-based) compounds, and are believed to have formed in the cold outer solar sytem. Scientists believe both are "...ancient remnants of the earliest years of the formation of our solar system more than four billion years ago." When asteroids collide, meteroids, smaller rocky bodies, often result. Meteroids are also formed when a comet passes near the sun, and the heat releases dust particles from the comet's icy tail. When a meteroid or asteroid enters the Earth's atmosphere, it ignites, creating a visible streak of light
called a meteor. If the object doesn't vaporize completely and crashes into the Earth, it's called a meteorite. And now that you have all your terminology down pat, you're ready to witness some upcoming (relatively) near-hits with assorted near-Earth objects.
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