Skywatchers will finally be able to enjoy the thrill of observing «shooting stars» again this week as the April Lyrids meteor shower arrives after a three-month-long meteor drought.
For those who enjoy watching the night sky for the sight of meteors, popularly referred to as «shooting» or «falling» stars, it has been rather quiet these last few months. There are many meteor showers that occur during the course of the year, but only ten are recognized as the ‘principal’ meteor displays. The last such shower to take place was the Quadrantid meteor shower on January 3. Since then, there have been no other noteworthy meteor showers to look for.
Finally, after 109 days — more than 15 weeks — we will have an opportunity to enjoy the nocturnal spectacle again with the April Lyrids.
The Lyrid meteor shower has been known for millennia. Records from Chinese chronicles show they’ve been appearing regularly since at least 687 B.C.
In his lengthy tome, Meteor Showers and their Parent Comets, (Cambridge University Press, 2006), author Peter Jenniskens noted that the annual Lyrid shower «has always been my favorite. After the low rates in the cold months of February and March, this shower is the proverbial swallow of spring for observers in the northern hemisphere.»
The 2022 version of the Lyrids is predicted to reach its maximum on Friday (April 22) in the morning hours. The radiant — the emanation point for these meteors — is about 6 degrees southwest of the brilliant bluish star Vega in the constellation of Lyra, which is ascending the northeast sky during the late evening hours and stands practically overhead at the break of dawn. The moon, one day shy of last quarter, however, will somewhat interfere with the light of the meteors.
Any meteor whose path, extended backward, goes within a few degrees of Vega is likely to be a Lyrid. The Lyrids are rich in faint meteors, with occasional bright ones. They are considered to be one of the weaker of the principal displays. Compared to the August Perseids and December Geminids, which can produce many dozens of meteor sightings during the course of an hour’s watch, the Lyrids generally yield only about 10 to 20 meteors per hour at maximum.
Usually, this shower is above one-quarter peak strength two days before and after maximum, so if the weather in your area is unsettled on the morning of the 22nd, you still have a chance to catch a few Lyrids a day or two before or after the time of their peak activity.
But there is always the small chance of a surprise.
1803: A storm of meteors
The April Lyrids sometimes have provided spectacular displays, as in 687 B.C. when Chinese records said «stars fell like rain» and at least a dozen other times since. The story is often told of how residents of Richmond, Virginia, were rousted out of bed by the fire bell on the morning of April 20, 1803. The fire that had broken out in the armory was quickly extinguished, but this gave the townspeople a chance to see meteors falling in great numbers from all parts of the sky.
Another account was a letter, published in the Raleigh, North Carolina, Register:
«We, the undersigned . . . being on Wednesday night, the 20th of April, out at a fishing party, and returning home about 1 o’clock A.M., were alarmed with the appearance of a shooting of stars; the whole hemisphere as far as the extension of the horizon, seemed to be illuminated; the meteors kept no particular direction, but appeared to move every way. We viewed the phenomenon for the space perhaps for half an hour with amazement, during which time no intermission appeared. We distinctly heard a hissing in the air, but heard no reports. The above statements may be relied on as facts.»(Signed by four men).
Other similar accounts came from New York, Massachusetts, New Hampshire and Delaware.
The meteor outburst of 1803 was completely unexpected. Very little was known about meteors in the 18th and 19th centuries, except for the slight increase in their numbers each year during early August. Today we know that the progenitor of the Lyrid meteors is Comet Thatcher which circles the sun in a roughly 415-year orbit and was last seen in the spring of 1861.
A brief outburst of 100 meteors per hour was reported in 1922. In 1982, rates unexpectedly reached 90 for a single hour, and a staggering 180 to 300 per hour for a few minutes. ‘It is indeed possible that many past Lyrid outbursts were missed simply due to observational gaps,’ writes Paul Roggermans in Handbook for Visual Meteor Observations (Sky Publishing Corporation, 1989).
So maybe it wouldn’t hurt to set the alarm clock for 3 or 4 a.m. on the morning of April 22 for a brief look out the window, moonlight notwithstanding.
Hey . . . you never know.
The next significant meteor display is scheduled to take place during the first week of May, the Eta Aquarids. This shower is one of the most popular annual events for meteor observers in the Southern Hemisphere; one of the best of the annual showers. Unfortunately, northern observers are handicapped by the low altitude of the radiant of this shower, plus the arrival of the dawn twilight just as the radiant appears. The meteoroids produced by this shower can be traced to Halley’s Comet. The peak for the 2022 Eta Aquarids is due on the morning of May 6.
But there is a second meteor shower in May which might very well end up being the best of the year.
An ‘all or nothing at all’ meteor display
Not many people have heard of the Tau Herculid shower. Normally, it produces no more than a few meteors during an entire night’s watch. But things radically changed when late in 1995, the nucleus of Comet 73P/Schwassmann-Wachmann 3 (the shower’s parent body) fragmented. Now a number of meteor dynamicists have confirmed what I had suggested last year: A stream of particles ejected during the comet’s disruption may yield a dramatic outburst at the end of May 2022.
This prediction, however, is uncertain because no one knows for sure how fast the expulsion of fresh comet dust left 73P’s disintegrating nucleus. However, we all agree that whatever occurs will take place around 1 a.m. EDT (0500 GMT) on May 31. This is splendid timing for the southern half of North America, including virtually all of the contiguous U.S. (evening twilight will interfere for the Pacific Northwest and virtually all of Canada). Even better, light from the moon, one day past its new phase will not interfere.
The cloud of cometary debris will strike Earth at a very slow speed of 10 miles (16 kilometers) per second, which ordinarily would yield very faint meteors. However, the shower’s radiant will be high in the sky for the Americas, and the meteoroid swarm might prove dense enough to produce a spectacular visual show nonetheless.