The Moon is in a cooperative mood tonight -- it stays out of the way of a meteor shower. The resulting dark skies could make it one of the best showers of the year.
The Geminid shower is named for the constellation Gemini, which soars high across the sky during the night. If you trace the paths of the meteors across the sky, they all point back toward Gemini. The meteors can appear just about anywhere, though, so you don't have to look at Gemini to see them.
The meteors are bits of debris from a comet. As the comet gets close to the Sun, its outer layers of ice vaporize, releasing bits of rock and metal. These bits of debris spread out along the comet's orbital path. When Earth crosses through this path, many of the comet grains plunge into the atmosphere at tens of thousands of miles an hour. They vaporize, forming the bright streaks of light known as meteors or shooting stars.
Most of the bits of debris are the size of BBs or smaller. They burn up quickly, and aren't all that bright. You need a dark sky to see them -- city lights overpower them.
But a few of the bits are bigger -- the size of pebbles or larger. They form much brighter meteors -- bright enough to see even from the city. And they can leave glowing trails that remain visible for several minutes -- under dark skies. Unfortunately, these bright meteors are rare. But you never know when one might pop up -- so keep your eyes on the sky for the Geminid meteors.
Script by Damond Benningfield, Copyright 2009
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