A time lapse image of the 2012 Geminids meteor shower. (NASA/MSFC)
One of the most spectacular meteor showers of the year, the Geminids, will peak this year on Monday morning, Dec. 14, lavishing the skies with as many as 120 meteors every hour.
And this year, the absence of the moon means darker skies while you enjoy the "falling stars."
Good Meteor Watching
If the weather is nice, cold December mornings often bring crystal clear skies, and this year the waning crescent moon will be gone most of the night, only appearing in the last moments before dawn as a thin sliver.
It’s simple math: abundant meteors, plus a clear dark night, minus the moonlight, equals the possibility of dazzling rewards!
How To Watch the Geminids
After midnight following Sunday evening, in the early morning hours of Monday, Dec. 14, find a good, safe place where you can set up a cot or roll out a blanket on the ground and look up.
The meteors will appear to radiate from near Gemini, the Geminids’ namesake constellation. By 2 a.m., Gemini will be almost directly overhead, 85 degrees above the southern horizon. Look for the “twin” stars Castor and Pollux, a pair of equally bright stars set about five degrees apart, or the width of four fingers.
With your sights set high, lay back and relax as (You hope!) a multitude of meteors rain down around you. If conditions are good, you may see two or so each minute. Though their radiant point is in Gemini, the meteors can appear anywhere in the sky, so use your peripheral vision to catch as many as you can.
Cloudy Weather Option: With a Bay Area forecast of cloudiness on Sunday evening and possible rain Monday morning, if you still want to see Geminids, check out the NASA Meteor Watch page, where the shower will be live-streamed from a camera at NASA's Marshall Space Flight Center in Huntsville, Alabama from 5:00 p.m. Sunday evening to 1:00 a.m. Monday morning, PST.
If you live in or near a city, the light from cars, buildings, billboards, and streetlamps will reflect from particles in the atmosphere above, forming a pale glow to compete with the light of meteors, particularly the fainter ones.
Though this won’t prevent you from enjoying the brighter meteors, it will subtract from the number you can see, so finding a place with dark skies, far away or sheltered from urban lights, will add to the experience.
Here are some ideas for good viewing places around the Bay Area.
Where Do the Geminids Come From?
Meteor showers happen when Earth passes through a trail of dust, usually left behind by a comet as it orbits close to the sun.
When Earth plows through the comet trail, the dust grains encounter our planet’s atmosphere at speeds of 20 or more miles per second and burn up in a flash. The meteor streaks you see are located 40 to 50 miles above the Earth’s surface. Meteor trails can be very bright and, because the dust grains travel so fast, the trails can be very long. But each meteor is only a small fleck of rock or metal, usually no larger than your fingernail.
Unlike most showers, the Geminids’ dust trail was left behind by an asteroid, named 3200 Phaeton.
This asteroid, of a variety sometimes called a “rock comet,” orbits the sun once every 1.4 years. When it gets close to the sun and is warmed by its rays, frozen volatile materials (mostly water ice) in the asteroid evaporate and blow off into space, carrying bits of dust.
Gone In a Flash
As you wait for the thrill of the next meteor to cross the sky, think about this: that bit of rock or metal of each meteor spent the last five billion years or so drifting randomly around the solar system or riding inside a comet or asteroid. Then, flash! It’s gone. And you saw it.
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