Skywatch Special: The Geminid Meteor Shower

[obby]

The Geminid meteor shower, which peaks on December 14, is a celestial event not to be missed. Of all the annual meteor displays, the Geminids produce the most consistent and satisfactory show, even occasionally outperforming the perennial favorite, the Perseids, which occur in August.

Where to look and when

Gemini is a bright winter constellation that rises due east this time of year around 9 o'clock Eastern Time and is overhead by 12:30 a.m. ET. It contains two bright side-by-side stars aligned northwest to southeast. The southernmost star is orange-hued Pollux. The northernmost star is white Castor. It is near this star that the meteors radiant lies. A radiant is the point in the sky from where meteors appear to "radiate" during a meteor shower. Therefore, this is the region of focus during Geminid observing.

On the other hand, be aware that Geminid meteors can appear almost anywhere in the sky, even opposite the radiant. To be a true Geminid, a meteor's path across the heavens must point back toward the radiant in Gemini. If it doesn't, you've seen a "sporadic" meteor, one that you'd see on almost any night of the year.

Unfortunately for those in the United States, this year's expected Geminid peak occurs during the day on the 14th, specifically, 1 p.m., ET. As I've mentioned in space.com's Skywatch column, I suggest observers begin looking for meteors on either side of this peak first during the predawn hours of the 14th, say around 3 a.m. ET, and again during the evening hours up to around 1 a.m. ET or so.

If you have only one shot at observing the Geminids, however, I would suggest the predawn hours of the 14th. After midnight, the night side of Earth faces into its orbit, thus sweeping up more meteoroids. During the evening hours, our view is more or less toward the wake of our orbit around the sun, away from all the action.

What to expect

During a typical Geminid peak, when the radiant is overhead in a dark sky, an observer can expect to see between 60 to 100 meteors per hour. Those in North America, however, being decidedly off-peak this year, can expect to see at most 10 or 15 per hour nearest to maximum. Geminids are bright and fairly slow, but only a few leave smoke trails. They are predominately white and bluish-white in color. They suddenly appear like an illuminated lance, streak through the sky for a few seconds, then vanish.

Make sure you position yourself at a dark sky location. If you are near streetlights, billboards or other outdoor ambient lights, you're just not going to see very many meteors; only the brightest. The moon this year sets during the early evening, so it won't obscure your view (as it will next year).

Where the Geminids originate

Most meteor showers occur when Earth passes through the stream of debris left in the wakes of comets when they pass into the inner solar system. The Geminids, however, have the distinction of being derived from an asteroid -- 3200 Phaethon -- which occasionally swings near Earth. Asteroids are not usually credited with creating enough detritus to yield a meteor shower, but they may be more responsible than previously thought. Observations of asteroid 253 Mathilde in 1997 by the Near Earth Asteroid Rendezvous (NEAR) spacecraft, confirmed that meteors not only had heavily battered it in the past, but that it is also composed of a porous and uniform material.

Perhaps 3200 Phaethon is composed of similar material. Particles might have easily been blasted away from its fluffy body, creating a debris stream that could produce a brief or even long-term meteor shower like the Geminids.

Essentials

This time of year, meteor watching can be a long, cold business. You wait and you wait for meteors to appear. When they don't appear right away, and if you're cold and uncomfortable, you're not going to be looking for meteors for very long. Therefore, make sure you're warm and comfortable. I used to observe from a sleeping bag, then a chaise lounge. Now I indulge myself in a portable hammock with sleeping bags and pillows. The only danger here is falling asleep! I keep myself awake by scanning the stars with binoculars.

Warm cocoa or coffee take the edge off the chill, as well as provide a slight stimulus. It's even better if you can observe with friends. That way, you can keep each other awake, as well as cover more sky.

http://www.space.com/scienceastronomy/astronomy/geminids_meteor_991213.html

[philippio]

Nice. I've seen some pretty amazing meteor showers in the past. It's like seeing the universe's fireworks!

[mp3some]

Nice!!!

[justinjohnson]

Awesome. I love meteor showers. Cool stuff.

[funketeer]

meteor showers are silly

[xxgrooveericxx]

The sky is falling!!!

Ooops, nevermind....

I'll be looking up at the sky tonight....high high in the sky....high high.....high....

[sotuorlando]

DID SOMEONE SAY SHOWER...

[funketeer]

Who wants a golden shower???