WAUKESHA, WI – The annual Geminid meteor shower, whose peak occurs on the night of December 13, usually puts on a great show. Occurring less than a month after the Leonid meteor shower, the Geminid shower generally produces the brightest meteors of the year. In 2004, the Moon will be only 2 days past new phase, so its light will have no effect on viewing – ideal conditions for enjoying this celestial event.
The Geminids are so named because if you traced all the meteor trails backward, they would meet within the boundaries of the constellation Gemini. This point is called the “radiant” of the meteor shower. The actual radiant is approximately 3° northwest of the 1st-magnitude star Castor (Alpha [α] Geminorum).
Geminid meteors move relatively slowly, and many leave trails that remain visible even after the meteor itself has faded. In 2004, the shower will be active from about December 7 to 17, but the best time to see it – the peak – will be at 5 p.m. EST December 13. The peak occurs during the early morning hours December 14 for observers in Eastern Europe and Asia, but the Geminid meteor shower has a broad peak so – clear skies permitting – American observers will see an excellent show, too.
What are meteors?
Meteors are small – mostly sand-grain size – particles of rock and metal that Earth sweeps up during its orbit around the Sun. In space, these particles are called “meteoroids.” When they burn up in the atmosphere, they are called “meteors.” If they survive the fiery ordeal of passage through our thick blanket of air and land on Earth, they are then known as “meteorites.” No meteorites are generated from meteor showers – the particles are too small.
Where do meteor showers come from?
All meteor showers except the Geminids are caused by the passage of comets. When a comet swings around the Sun, it leaves a trail of debris (small meteoroids). Sometimes, the orbit of this debris crosses Earth’s orbit. When Earth runs into this stream of particles, we experience a meteor shower.
One-of-a-kind meteor shower
Astronomers first noted the Geminid shower in 1862 and searched for its parent comet for more than a century. In 1983, astronomers discovered the asteroid 3200 Phaethon, and they soon realized its orbit is identical to the Geminid meteoroid stream. This was the first time an asteroid had been linked to a meteor shower. Some suggest Phaethon is, in fact, a worn-out comet.
For more information on meteors, visit: Meteors and meteor showers.
Observing the event
Note: The best viewing for this year’s Geminids will be after sunset when the sky darkens.
Usually, after midnight is the best time to observe a meteor shower. Because the Geminid peak occurs at 5 p.m. EST, however, begin watching at dusk Monday, December 13.
Geminids can appear in any part of the sky. To maximize your chances of seeing these meteors, though, face generally east and look one-third to one-half of the way up in the sky from dusk to about 9 p.m.
From 9 p.m. to midnight, look generally from halfway up in the sky to overhead. At any time, glancing around won’t hurt anything. If you observe late into the night, look overhead.
To maximize the chances of seeing Geminids, a clear, dark sky is preferable. Dark means at least 40 miles from a major city. No optical aid (telescope or binoculars) is required. The naked eye works best for meteor showers because your field of view is not restricted. Suggested gear includes a lawn chair, lots of warm clothing – more than you think you’ll need, cookies or fruit, and a warm, non-alcoholic beverage. Alcohol interferes with the eye’s dark adaption as well as the visual perception of events.
Geminid meteor shower mythology
Gemini the Twins, according to Roman mythology, represents two legendary brothers (Castor and Polydeuces) who accompanied the hero Jason (leader of the Argonauts) on his epic voyage to recover the Golden Fleece. Castor and Pollux (the names of the constellation’s two brightest stars) were the twin sons of Jupiter and Leda and were born in an egg, supposedly because Jupiter had taken the form of a swan prior to seducing Leda.
Geminid meteor shower images available for reprint
December 9, 2004