Photograph by Dennis Di Cicco, Sky and Telescope

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A shooting star streaks across the sky during the summer Perseid meteor shower. The Geminid meteor shower this weekend may best it.

Photograph by Dennis Di Cicco, Sky and Telescope

Gem of a Meteor Shower on Tap This Weekend

Break out a lawnchair and a warm coat for a December meteor shower.

Kick off the holiday season with celestial fireworks, stargazers, with the weekend's peak of the annual Geminid meteor shower.

Despite a bright quarter moon rising around midnight this year, the meteors should dash across the sky at a rate of anywhere from 20 to 60 per hour on December 13 and 14, if clouds and weather permit a glimpse of the starry shooters.

Noted for their numbers, the Geminids are among the strongest and most reliable sky shows around, even at times besting August's famed Perseids. (See "Meteor Madness" to learn more about meteors.)

If clear skies prevail, head for the dark countryside far from the bright city lights to see the most shooting stars. But even suburbanites should get to see at least some of the biggest and brightest meteors zipping across the sky, around one every three minutes or so.

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The Geminid meteors appear to radiate out from their namesake constellation, which rises in the east in the late evening.

Holiday Highlights

Historically, the Geminids were overlooked, simply because they arrive during frigid winter nights close to the busy holiday season. But that is beginning to change thanks to their rising intensity in recent decades.

The Geminids were first really noticed back in 1862, when fewer than 20 shooting stars an hour were recorded. But since then they have skyrocketed to well over 100 a night in some years, particularly when the skies were moonless at peak times.

What is the reason for the uptick? Astronomers believe that Earth is plowing deeper every year into an ancient stream of debris left behind by a mysterious three-mile-wide (five kilometers) comet or asteroid orbiting in the inner solar system.

The shooting stars, which are really sand-size meteors, all appear to be chips off of a bizarre asteroid-like object, called 3200 Phaethon. Discovered in 1983 by a NASA satellite, astronomers quickly matched Phaethon's year and orbit precisely with the Geminids, making it a prime candidate for the source of the meteors.

But unlike other meteor showers that astronomers know derive from material shed from icy comets melting as they pass close to the sun, the true nature of the Geminids' parent object has left scientists baffled. It may be a curiously icy asteroid instead. (For a fun glance at the origins of meteor shower science, look here.)

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Phaethon's orbit around the sun is highly elongated, much like a comet's.

Don't Blink

The Geminids hit the atmosphere at around 20 miles (30 kilometers) per second, creating beautiful long arcs across the sky—many lasting a second or two.

Favoring observers in the wintry Northern Hemisphere, the shower's radiant—the point in the sky from which the meteors appear to originate—is in its namesake constellation Gemini, which rises above the eastern horizon after 9 p.m. in the evening.

Observers should head outside between 8 p.m. and midnight before the quarter moon's glare blocks the views of fainter meteors.

While there is no need for telescopes or binoculars—meteors race across large parts of the sky too fast to focus on—don't forget to lie back with a warm sleeping bag and some hot chocolate to enjoy the show.

Happy hunting!

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