For those whose appetite for "shooting stars" was whetted by last months spectacular Leonid meteor shower, the Geminid meteor shower will reach peak activity Thursday night, Dec. 13, and into the early hours of Friday morning.

Anyone willing to brave the chill will likely see a fine display, weather permitting. The Geminids are usually the most satisfying of all the annual meteor showers, even surpassing the famous Perseids of August.

Studies of Geminid displays in recent years reveal showers rich both in slow, bright, majestic meteors and fireballs as well as faint meteors, with relatively fewer objects of intermediate brightness.

Many are yellowish in hue. Some even appear to form jagged or divided paths.

Meteors are created when bits of dust, typically no larger than a grain of sand, vaporize due to friction as they plunge through Earth's atmosphere. Before they enter the atmosphere, these bits of space debris are called meteoroids.

Geminid meteoroids are several times denser -- some 2 grams per cubic centimeter -- than the bits of comet dust that supply most meteor showers, according to meteor specialist Neil Bone. Add this to the relatively slow speed with which Geminids encounter Earth (22 miles per second), and you have the recipe for meteors that tend to linger a bit longer in the sky.

Noticeable activity may begin as early as Monday night, Dec. 10. Geminid rates tend to steadily increase beginning about three days before maximum, reaching roughly above a quarter of their peak strength. They then drop off more sharply afterward, so the best show may be over with by the following weekend. Those late Geminids, however, tend to be especially bright.

Renegade forerunners and late stragglers might be seen for a week or more before and after maximum.

While the Geminids typically perform excellently in any year, this year they will coincide with a New Moon that will not interfere in the slightest with watching this reliable display. Peak activity is expected around 11 p.m. EST (8 p.m. PST) on Dec. 13.

Under normal conditions on the night of maximum activity, with ideal dark-sky conditions, at least 60 to 120 Geminid meteors can be expected to burst across the sky every hour, on average. Local light pollution, of course, greatly cuts the numbers.

In 2001, however, along with the lack of significant moonlight, North Americans, particularly those who live in the eastern U.S. and Canada, conceivably could catch the very crest of the shower, when the hourly rates might even exceed 120.

As astronomers Stephen Edberg and David Levy note in their book, Observing Comets, Asteroids, Meteors and the Zodiacal Light, "If you have not seen a mighty Geminid fireball arcing gracefully across an expanse of sky, then you have not seen a meteor."

After 10 p.m. local time, Geminids should appear in greater numbers because the showers radiant, a point in the sky near the bright star Castor from where the Geminids appear to emanate, will have climbed fairly high in the sky. The "Gems" will be especially noticeable between 1 a.m. and 3 a.m. EST, as their radiant point will be passing very nearly overhead.

Remember the meteor watchers rule of thumb: the higher a showers radiant, the more meteors it produces all over the sky.

This time of year, meteor watching can be a long, cold business. When meteors don't appear right away, and if you're cold and uncomfortable, you're probably not going to be looking for meteors for very long. Therefore, make sure you're warm and comfortable. Warm cocoa or coffee take the edge off the chill, as well as provide a slight stimulus.

It's even better if you can watch with a companion. That way, you can keep each other awake, as well as cover more sky.

Also, give your eyes time to dark-adapt before starting. As your pupils dilate, more faint meteors will be visible.

The Geminids stand apart from the other meteor showers in that they seem to have been spawned not by a comet, but by 3200 Phaeton, an asteroid that crosses Earth's orbit. Then again, the Geminids may be comet debris after all: some astronomers consider Phaeton to be the dead nucleus of a burned-out comet that somehow got trapped into an unusually tight orbit.