Earth Weather / Space Weather

Lyrid Meteor Shower

Posted by: Susie77, 7:47 PM GMT on April 14, 2012

From: Space Weather

Every year in late April Earth passes through the dusty tail of Comet Thatcher (C/1861 G1), and the encounter causes a meteor shower--the Lyrids. This year the shower peaks on Saturday night, April 21st. Forecasters expect 10 to 20 meteors per hour, although outbursts as high as 100 meteors per hour are possible.

Lyrid meteors appear to stream from the bright star Vega in the constellation Lyra:

In fact, Lyrids have nothing to do with Vega. The true source of the shower is Comet Thatcher. Every year in April, Earth plows through Thatcher's dusty tail. Flakes of comet dust, most no bigger than grains of sand, strike Earth's atmosphere traveling 49 km/s (110,000 mph) and disintegrate as streaks of light.

Lyrid meteors are typically as bright as the stars in the Big Dipper, which is to say of middling brightness. But some are more intense, even brighter than Venus. These "Lyrid fireballs" cast shadows for a split second and leave behind smokey debris trails that linger for minutes.

Occasionally, the shower intensifies. Most years in April there are no more than 5 to 20 meteors per hour during the shower's peak. But sometimes, when Earth glides through an unusually dense clump of comet debris, the rate increases. Sky watchers in 1982, for instance, counted 90 Lyrids per hour. An even more impressive outburst was documented in 1803 by a journalist in Richmond, Virginia, who wrote:

"Shooting stars. This electrical [sic] phenomenon was observed on Wednesday morning last at Richmond and its vicinity, in a manner that alarmed many, and astonished every person that beheld it. From one until three in the morning, those starry meteors seemed to fall from every point in the heavens, in such numbers as to resemble a shower of sky rockets..." [ref]

What will the Lyrids do this year? The only way to know for sure is to go outside and look.

Experienced meteor watchers suggest the following viewing strategy: Dress warmly. Bring a reclining chair, or spread a thick blanket over a flat spot of ground. Lie down and look up somewhat toward the east. Meteors can appear in any part of the sky, although their trails will tend to point back toward the radiant--i.e., toward Vega.

Vega is a brilliant blue-white star about three times wider than our Sun and 25 light years away. You might have seen Vega in Carl Sagan's movie Contact. It was the source of alien radio transmissions to Earth.

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1. RobDaHood 8:08 PM GMT on April 14, 2012
Susie, Thanks! Always appreciate a heads up on space weather. I get busy and don't keep up. Nice write-up too! Member Since: September 2, 2008 Posts: 80 Comments: 26412

2. Susie77 1:36 AM GMT on April 15, 2012
You're welcome, Rob. I just copied n pasted. lol Member Since: April 14, 2002 Posts: 563 Comments: 517

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