Jimmy Westlake: A great year for Geminid meteors
December 8, 2010
Steamboat Springs — The constellation of Gemini the Twins is about to become a hot spot of activity for the next two weeks. Skywatchers will notice lots of fiery streaks of light coming from Gemini as a result of the annual Geminid meteor shower.
Unlike the August Perseid meteor shower that has occurred every year for centuries, the Geminid meteor shower is a relative newcomer.
No one reported seeing any Geminid meteors before 1862, but every December since that year, the Geminid shower has appeared on schedule and seems to be getting stronger and better each year. Astronomers predict that this year's Geminid meteor shower could be the best, reaching 120 meteors per hour at its peak.
The Geminid meteors are unique because the parent body seems to be a rocky asteroid rather than an icy comet. In 1984, astronomers discovered a small object, about 3 miles across, orbiting along the same path as the dust swarm that generates our Geminid meteor shower. Now named Phaethon, this asteroid might be a burned out comet in disguise — that is, a comet that has lost all of its ice after many passes around the sun and now is just the rocky skeleton of a once-active comet. The trail of dust particles that follows Phaethon around the sun could be left over from its comet days.
You can begin to see a few Geminid meteors about a week before the shower peaks Monday night. A single observer might see dozens of "shooting stars" or meteors each hour near the peak. The meteors will fan out from a point near the twin stars Castor and Pollux in the constellation Gemini, but they will be visible across the sky.
Gemini rises above our eastern mountains well before midnight, so the action could start earlier than in most meteor showers. And Geminid meteors tend to be slower than the August Perseids or November Leonids, producing long, graceful streaks across the sky. The waxing gibbous moon will set about 1:45 a.m. Tuesday, the morning of the meteor shower's peak, leaving the sky dark and perfect for meteor-watching.
If the sky is clear on Monday night, bundle up against the cold, stretch out with a warm sleeping bag on the ground or in a comfortable recliner, and enjoy the fireworks. Remember, the closer to dawn Tuesday you look, the more meteors you are likely to see, until daylight begins to brighten the sky. Next year's Geminid meteor shower will be spoiled by a nearly-full moon, so you won't want to miss what could be the best meteor shower of 2010.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Alpine Campus. He is an avid astronomer whose photographs and articles have been published around the world. Check out Jimmy's astrophotography website at http://www.jwestlake.com.