Annual Meteor Showers - April's Lyrids

The Lyrid meteor shower may not win over many astronomy converts, but its long history and occassional surprise make it worth watching.

In spite of its interesting history, as well as the possibility of an occasional surprise, April's Lyrid meteor shower is not the sort of meteor shower that garners much attention, or wins over astronomy converts. Even experienced stargazers might hesitate when the alarm goes off sometime after midnight. On the other hand, the possibility of a sudden flurry of meteors, or the occasional blinding flash of a single meteor is all it takes to entice some observers out into the night, beneath the constellations.

The problem with astronomy is so much of it takes place in the middle of the night. That is an overwhelming obstacle when trying to convince others of the wondrous spectacles they're missing by staying in bed all night.

Occasionally star gazersare blessed with a P/R extravaganza like comet Hale-Bopp, but more often the best they can offer is a planetary conjunction, lunar eclipse or the possibility of an auroral display.

Meteor showers such as the Perseids in August, and the Geminids in December are dependable enough that astronomers can promise the astronomically indifferent they'll see something. It may not be a downpour, but it will be a show.

The Lyrid meteor shower, so named because the meteors appear to radiate from the constellation Lyra, is another story. Even dyed-in-the-wool stargazers might be tempted to hit the snooze button and roll over.

The Lyrids are considered a lesser meteor shower at best. Active from April 16th through the 25th, the peak, which falls on the 22nd, lasts but a few hours and produces only 15 to 20 meteors an hour. What gets stargazers out of bed is the possibility of a surprise, which might be several hundred meteors in a short period of time.



In modern times, the Lyrids' greatest such surprise occurred in 1803 when observers counted 700 meteors per hour. Ironically, this was at a time when meteor showers were not recognized as annual phenomena.

In spite of the 1803 outburst, little attention was given to this meteor activity until 1835. On the heels of the great Leonid meteor storm, astronomers concluded meteor showers occurred annually. At that time a connection was made between the Perseid meteor shower and periodic comet Swift-Tuttle, and the Leonids were linked to the newly discovered periodic comet Temple-Tuttle.

A few astronomers rolled up their pant legs and began wading through the centuries, hoping to identify other annual meteor events. Edward Herrick, an astronomer in Connecticut, who found records of possible Lyrid activity in 1095, 1096 and 1122, organized a meteor watch in April 1839. Weak, but definite activity was observed.

Just as meteor astronomy was slow to get a toehold in the scientific community, the Lyrids were largely ignored until the 1880's. In Vienna, Edward Weiss was busy calculating near misses between the earth and the orbits of comets. He found that the orbit of comet Thatcher came within 186,000 miles of the earth's orbit on April 20th.

The link between the Lyrid meteor shower and comet Thatcher was confirmed mathematically a few months later.

Further legwork revealed the Lyrids to be the earliest known recorded meteor shower. Records of the shower were found in China from 687 BC and 15 BC. They were also recorded in Korea in A.D.1136.

In addition to the outburst in 1803, nearly 100 meteors per hour were observed in 1922. After an increase in 1981, and rates between 75 and 250 per hour in 1982, some astronomers now believe there may be a Lyrid meteor storm with a period of 60 years. However, in 1999 nearly 30 Lyrids per hour were counted, and in 1996 and 2000 peak rates lasted nearly 12 hours.

Because they hit the atmosphere nearly head-on, Lyrid meteors are swift. They are occasionally spectacularly bright, and nearly a quarter of them display persistent glowing trains. Their radiant, that area of the sky from which they appear to radiate, is near the border between the constellations Lyra and Hercules, southwest of the very bright star Vega. It rises about 7:30 p.m. local time, and is highest around 4 in the morning.

Like all meteor showers, the higher the shower's radiant, the better the chance of seeing meteors. Consequently, more meteors are possible between midnight and dawn. It is also better to observe from a dark location, well away from the glare of city lights, which greatly reduces the number of meteors seen.

Perhaps a few hours of stargazing isn't for everyone, and given the typical 15 to 20 meteors per hour an observer might see during the few hours of a Lyrid peak, staying in bed doesn't seem like such a bad idea. But watching a meteor shower that was observed more than 2500 years ago puts it in an historical context. And if just one meteor bursts like a camera flash, or blazes across the sky, leaving a glowing trail behind, that ups the ante. Maybe it's not what is expected of the Lyrid meteor shower that makes them worth watching, but what might be missed if we stay in bed.

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