Sky-watchers will get a chance to witness one of the oldest known annual meteor showers this weekend—and conditions promise to be ideal for viewing the shooting stars.
Northern Hemisphere skies will light up as the Lyrid meteor shower peaks late on April 21 and into the very early hours of April 22. This year, the quarter moon will set soon after local midnight, creating dark skies just as the shower kicks into high gear.
While the annual Lyrids are usually quite modest, with peak rates of 15 to 20 meteors an hour, the sky show is considered to be one of the most reliable. This celestial event is also known to deliver bright and impressively fast streaks across the night sky, with surprise bursts of extra activity on rare occasions. Within the last century, the Lyrids produced meteor outbursts with rates clocked at over a hundred shooting stars an hour in 1922 and 1980.
The rates can change so dramatically because of the way meteor showers work. Like bugs hitting the windshield of a fast-moving car, meteors pelt Earth when the planet passes through a particularly dense part of the stream of debris left behind by a comet. (Here’s why Isaac Newton believed a comet caused the biblical event known as Noah’s flood.)
In case of the Lyrids, that debris comes from Comet Thatcher, which made its last close approach to the sun in 1861. The comet's 416-year orbit is skewed nearly perpendicular to the plane of the solar system, which helps keep the stream of material following behind the comet from being scattered by the gravitational pull of the planets. Astronomers believe this may be why the Lyrids have been a reliable sky show for centuries.
Records of the Lyrids stretch back more than 2,600 years. Chinese astronomers in 687 B.C. noted that this meteor shower was so prolific that the meteors were “falling like rain.” Fast forward to 1803, and newspaper articles tell of a Lyrid meteor storm that was widely witnessed across the eastern United States, with shooting stars continually falling in just about every direction, like rockets in reverse.
While meteors can appear in any part of the sky, most will seem to radiate from the shower's namesake constellation Lyra, the harp. Look for Lyra near the brilliant star Vega, which now shines nearly straight overhead in the predawn hours for stargazers across the Northern Hemisphere.
Because the shower’s radiant rises above the northeast horizon in the early evenings, observers should be able to see meteors all night long. In Southern Hemisphere skies, Lyra will be at or below the horizon, so viewers there will see just a sprinkling of meteors.
The meteors are mostly the size of grains of sand, and they burn up as they fall to Earth at speeds of more than a hundred thousand kilometers an hour. About 15 percent of them leave behind persistent, smoky trails that are clearly visible for a few minutes thereafter.
Sky-watchers should also be on the lookout for fireballs, which are space rocks that and can be as large as a golf ball or even a basketball when they hit the atmosphere and so are brighter than average meteors.
If you have clear skies, going to the dark countryside away from light pollution will increase your chances of seeing meteors. But even if you are stuck in bright suburbia, you may be able to catch at least half a dozen shooting stars an hour, with possibly a fireball or two mixed in over the course of the night.
Because the meteors race across much of the overhead sky, there is no need for binoculars or telescopes. In terms of equipment, reclining lawn chairs, warm blankets, and a hot chocolate are really all that you need to enjoy this spring shower.
Here’s to making many wishes!
Andrew Fazekas, the Night Sky Guy, is the author of Star Trek: The Official Guide to Our Universe. Follow him on Twitter and Facebook, and tune in on Nat Geo’s Facebook page at 1 p.m. ET on April 20 to see Andrew live and ask your questions about the Lyrid shower.