Meteor shower -- or two-- Thursday night

Elizabeth Weise, USA TODAY | USATODAY

Show Caption Hide Caption Geminid meteor shower The Geminid meteor shower, which to viewers on Earth will appear to emanate from the constellation Gemini. It will be at its best after dark on Thursday, December 13, and before dawn on Friday, December 14.

As many as 100 shooting stars an hour could light up the sky

Eat your hearts out, Christmas lights. Thursday night will see a real celestial show as the Geminid meteor shower, one of the two biggest of the year, sprinkles the night sky with falling stars.

And a Russian astronomer is predicting a whole new meteor shower might happen at the same time, giving sky-watchers a double dose of thrills.

"The Geminids are one of the best performers among the meteor showers of the year," says Mark Hammergren, an astronomer at the Adler Planetarium in Chicago.

As many as 100 shooting stars an hour are possible.

The show should start just after sunset local time across North America and continue until dawn. "Meteors will appear in every part of the sky," says Alan MacRobert, a senior editor with Sky & Telescope magazine.

The shower is named for the constellation Gemini because it looks as if the meteors radiate out from it, although they don't.

The Geminids are "right at the top or near the top of most people's lists of meteor showers," Hammergren says.

The second shower comes from a comet named Wirtanen, discovered in 1948, which may cause a new meteor shower.

Meteors are the debris trail of comets, which leave behind bits of ice and rock dust as they swing near the sun on their long, elliptical orbits. The shooting stars appear when that dust and ice burn up in Earth's atmosphere.

Wirtanen takes 5.4 years to orbit the sun. It has come close to Earth's orbit many times, but the Earth has never before run through its debris stream. However, computer models run by Russian forecaster Mikhail Maslov predict it could happen Wednesday or Thursday.

Astronomers haven't yet named the new shower because they don't know if it will produce meteors.

"Dust from this comet hitting Earth's atmosphere could produce as many as 30 meteors per hour," says Bill Cooke of NASA's Meteoroid Environment Office.

"Meteors from the new shower, if any, will be visible in the early evening, with the Geminids making their appearance later on and lasting until dawn," he says. Maslov's model predicts that they will move slower than the Geminids.

For the Geminids, those who brave the cold and find a dark area to watch from should be rewarded with "one or two meteors a minute," MacRobert says. Even in a suburb or brightly lit city, "you might see one every couple of minutes."

The Geminids peak Thursday night into Friday morning, but they'll be visible in lesser numbers as late as Friday night.

Weatherwise, much of the country will have clear skies and seasonably cool temperatures Thursday night. The best areas for viewing the meteor shower will be the Northeast, the Mid-Atlantic, the Midwest, the Plains and the interior Southeast, according to AccuWeather meteorologist Mark Paquette.

The West might be the worst for seeing the shooting stars, Paquette says, because much of the West Coast from the Pacific Northwest down to California will be mostly cloudy with some rain possible. Other likely cloudy spots: southern Texas and the Southeast coast.

If skies are clear, there will be a bonus with this meteor shower: a new moon, so the darker sky will make the meteors easier to see. Paquette says the best time for viewing will be shortly after twilight. Look to the east or northeast to see the most meteors.

The key to seeing the Geminids is to suit up in warm clothes and prepare to spend some serious time outside in the dark.

"It's not going to do any good to go out to your front porch and just look up for a few minutes," Hammergren says.

The eye needs up to 20 minutes to adjust to night vision, he says. Find a dark area away from lights, if possible, and avoid looking at any lights. If you can't get away from city lights, Hammergren says, "at least find a shadowed place that has a wide open view of the sky and doesn't have any light actually glaring into your eye."

The origins of the Geminids is not well understood. Most meteor showers come from icy comets, but these appear to spring from an odd, rocky object named Phaeton after the son of the Greek sun god Helios.

"It's a new type of object that astronomers are talking about," says Rick Kline of Cornell University's Astronomy Department. "It's still something of a mystery."

Contributing: Doyle Rice