EARTH DAY METEOR SHOWER: Earth is passing through a stream of debris from ancient Comet Thatcher, source of the annual Lyrid meteor shower. Prof. Peter Brown of the Universiy of Western Ontario reports that “the Canadian Meteor Orbit Radar (CMOR) just finished processing orbital data from last night and the Lyrids are showing up quite nicely. The meteor rate is near 15 per hour so visual observers should have had a good view early this morning and should be able to easily detect the shower tonight.”
Click to view an all-sky map of CMOR meteor radar echoes on April 22nd:
The bright pink blob pinpoints the Lyrid radiant in the constellation Lyra. Other lesser showers are active, too, but they are much weaker. If you see a meteor tonight, it is probably a Lyrid.
Usually the Lyrid meteor shower is mild (10-20 meteors per hour), but unmapped filaments of dust in the comet’s tail sometimes trigger outbursts ten times stronger. So far this year’s shower is trending toward the usual. “The shower is comparable in strength to what was seen last year – so far no surprises,” says Brown.
Forecasters expect the shower to peak on April 22nd between the hours of 10:00 UT and 21:00 UT.
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 Monday morning, April 22nd. 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.
LYRID METEOR SHOWER: Earth is approaching the debris field of ancient Comet Thatcher, source of the annual Lyrid meteor shower. Forecasters expect the shower to peak on April 21-22; a nearly-new moon on those dates will provide perfect dark-sky conditions for meteor watching. Usually the shower is mild (10-20 meteors per hour) but unmapped filaments of dust in the comet’s tail sometimes trigger outbursts 10 times stronger. [video] [Lyrid chat]