If the weather was clear after midnight Saturday night and if the Lyrid meteor shower of 2012 was good to you, you could have seen the sky falling. Every year at this time, the Earth passes through the orbit of an old comet called Thatcher, and the result is a meteor shower -- shooting stars, usually about 10 to 20 per hour, streaking across the night sky as debris from the comet enters the Earth's atmosphere and burns up. The comet is far away from us now; Thatcher orbits the sun once every 415 years in a long, elliptical orbit. But debris from it has spread out along its path, mostly pieces of dust or rock smaller than grains of sand. As they come slicing into the upper atmosphere, at speeds of more than 100000 mph, they burn up 50 to 70 miles over our heads. It is a quiet, vivid way for them to end. The Lyrids are one of the weaker annual meteor showers (most skywatchers prefer the Perseids in August or the Geminids in December), but this year the Lyrids coincided with a new moon. "Typical Lyrids are about as bright as the stars of the Big Dipper," said Bill Cooke, who heads NASA's Meteoroid Environment Office at the Marshall Space Flight Center in Alabama. "And it's not unusual to see one or two fireballs when the shower peaks." So-called fireballs happen if an unusually large piece of debris makes it into the lower atmosphere, breaking up -- sometimes audibly -- at altitudes of less than 20 miles from Earth. In general, there are more shooting stars in the morning ...
http://www.youtube.com/watch?v=HWubGt5hdgU&hl=en
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