Northern Hemisphere sky-watchers will see another round of celestial fireworks when the Lyrid meteor shower peaks in the early hours of April 22.
The annual Lyrids usually are quite modest as showers go, with peak hourly rates of 15 to 20 meteors. But the celestial event is known to produce surprises on rare occasions, making them worth watching, astronomers say. (Read about last year's Lyrids.)
"Brief outbursts of around a hundred meteors per hour have been noted a couple of times in the 20th century, and Chinese astronomers in 687 B.C. recorded Lyrid meteors falling like rain overhead," said Mark Hammergren, an astronomer at Adler Planetarium in Chicago, Illinois.
These unusual outbursts occur when Earth passes through a particularly dense stream or clump of debris in the comet's orbit, he said.
What do Lyrid meteors look like?
Lyrids are known to produce bright, fast-moving meteors, with about 15 percent leaving behind persistent smoky trails that are clearly visible for a few minutes afterward. (See pictures of last year's Geminid meteor shower.)
"Most visible meteors are caused by fragile clumps of rocky dust—[each] around the size of a BB [pellet]—burning up in the Earth's atmosphere," said Hammergren.
"A meteor as bright as the brighter stars in the sky may be as big as a penny."
Where in the sky will they appear?
While meteors can generally appear in any part of the sky, most will be streaming out from the shower's namesake constellation Lyra.
They'll appear to radiate out from the area of sky occupied by the brilliant star Vega, which now shines nearly overhead in the predawn hours.
Because Vega rises above the northeastern horizon in the early evenings, observers in the Northern Hemisphere should be able to see meteors all night long.
While the meteor rates officially spike in the predawn hours of April 22, observers can catch Lyrid stragglers streaking across the night sky from April 16 through April 25.
However, a challenge for Lyrid observers this year will be the glare from the bright moon that may wash out all but the brightest shooting stars in the earlier hours of the night, explained Hammergren.
"In general, meteors are more numerous after midnight, and so this may be especially true for the Lyrids this year after the moon sets in the predawn hours on April 22."
Where do the Lyrids come from?
The shower itself originates from leftover debris from the periodic comet Thatcher, whose orbit is skewed nearly perpendicular to the plane of the solar system. This leaves a stable debris trail that isn't subject to gravitational disturbances. (See asteroid and comet pictures.)
Astronomers believe this may be why the Lyrids have been a reliable show for sky-watchers for centuries, with rates that at times skyrocket.
What's the best way to watch the sky show?
While no one knows for sure if this year's Lyrids will be a sprinkle or a storm, Hammergren said it's one of the easiest celestial events to witness with the naked eye.
Getting out of the light-polluted city and into the countryside will increase your chances of seeing even the faintest meteors, he said. (Find out more about light pollution in National Geographic magazine.)
Because the meteors race across much of the overhead sky, there's no need for binoculars or telescopes.
So reclining lawn chairs, warm blankets, and hot chocolate are really all that you need to enjoy this spring shower.