April 22, 2012— -- Did you see it?
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 100,000 mph, they burn up 50 to 70 miles over our heads. It is a quiet, vivid way for them to end.
"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 hours because the morning side of the Earth faces forward as we orbit the sun, so it's less shielded. While the shower actually peaked Sunday morning for the U.S., meteors are often spotted several nights before and after.
Astronomers often say that meteor showers are best if you regard them as something to be savored, rather than awed by. But if you saw anything, please tell us. A meteor shower on a clear night can be a pleasant, restful show. And you'll have the satisfaction of knowing that Chicken Little was half-right: The sky was indeed falling ... harmlessly.