There are plenty of reasons to turn your gaze skyward near the end of the year. For some, it's a chance to watch for snowflakes. For people in the Southern Hemisphere, it's peak season for basking in the sun. But all over the planet, mid-December is when the annual Geminids meteor shower takes place.
What's generally one of the stronger displays of the year, both in terms of number of meteors and their respective size, is back. (The shower, which lasts for weeks but is most intense in mid-December, has already produced some impressive fireballs.)
The peak will occur on the night of Wednesday, Dec. 13, and in the early morning hours of Thursday, Dec. 14.
The meteor shower appears annually when Earth passes through the point where its orbital path intersects with a stream of debris cast off from the asteroid 3200 Phaeton. This year, the asteroid will be closest to Earth the night of Saturday, Dec. 16, when it zips by at a distance of about 6.4 million miles (10.3 million kilometers), which is nearly 30 times farther away from Earth as the moon is. (Sorry, disaster scenario fans.)
The constellation Gemini, meaning twins, was named by ancient observers for the mythological twins Castor and Pollux. They imagined the two standing side by side in the cosmos, and the stars where their heads would be also share their names. Most of the Geminid meteors will appear to originate to the right of the bright star Castor, which viewers will see as the twin standing to the right of his brother.
This origin point is called the meteor shower's radiant, because most of the meteors appear to radiate outward from this point. A good viewing strategy is to keep the radiant in the periphery of your sight, rather than staring directly at the point. And unlike many annual meteor showers, which are mostly visible in the early morning hours, the Geminids tend to be an all-night affair.
"Geminid activity is broad," said Bill Cooke, of the NASA Meteoroid Environment Office, in a NASA press release. "Good rates will be seen between 7:30 p.m. on Dec. 13 and dawn local time the morning of Dec. 14, with the most meteors visible from midnight to 4 a.m. on Dec. 14, when the radiant is highest in the sky."
If your local weather isn't cooperating, don't worry. NASA plans to broadcast the Geminid shower live via Ustream starting at sunset on Wednesday, Dec. 13. That's about 4:30 p.m. CST in Huntsville, Alabama, where NASA's Automated Lunar and Meteor Observatory is located.