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| | Astronomy Essentials | Space on Dec 06, 2014

Everything you need to know: Geminid meteor shower

Don’t let the moonlight discourage you. These meteors are bright! No matter your location, Geminid meteors will fall most abundantly after midnight on December 13 and 14.

The peak night of the 2014 Geminid meteor shower will probably occur on the night of December 13-14, though the night before (December 12-13) and after (December 14-15) may offer a decent sprinkling of meteors as well. The show starts at mid-to-late evening and ends at dawn. The meteors tend to be few and far between at early evening, but intensify in number as evening deepens into late night. Don’t let the late-night moonlight discourage you from watching after midnight, or during the peak viewing hours. These meteors are bright! No matter your location, the Geminid meteors will fall most abundantly in the wee hours after midnight on December 13 and 14.

Although the Geminid shower favors the Northern Hemisphere, it’s visible from the Southern Hemisphere, too. The Geminids start streaking the sky by mid-evening in the Northern Hemisphere, but people at temperate latitudes in the Southern Hemisphere may have to wait until late evening, or close to midnight, to see the beginning of the Geminid shower. Follow the links below to learn more about the Geminid meteor shower in 2014.

Moonlight a factor in Geminid shower in 2014

Why are these meteors called the Geminids?

How to find Gemini, the radiant point of the Geminid shower

An earthgrazer Geminid meteor possible at early evening

What causes the Geminid meteor shower?

How to watch the Geminid meteors

View larger. | Geminid meteor 2012 as captured by Henry Shaw of SummersMagic Photography.  Click here to learn from Henry how to take photos of meteors.

View larger. | Geminid meteor 2012 as captured by Henry Shaw of SummersMagic Photography. Click here to learn from Henry Shaw how to take photos of meteors.

Moonlight a factor in Geminid shower in 2014. The December Geminids are a particularly reliable and prolific shower, one of the finest of the year. In a year when moonlight doesn’t obscure the viewing, you can easily see 50 or more meteors per hour on the peak night of the Geminid shower. However, the waning moon might somewhat dampen this year’s display in the peak viewing hours, centered on about 2 a.m. local time.

But don’t let the moonlight discourage you. A good percentage of these yellow-colored Geminid meteors are quite bright, and may well overcome the moonlit skies.

Of course, you can always watch this shower during the evening hours before moonrise. The moon will rise quite late on December 13 and 14, creating a window of darkness for watching the Geminid shower in the evening. Keep in mind that the moon will rise about an hour later on December 13 than it will on December 14. Click here for custom sunrise/set calendar. Check boxes for moonrise/set times..

Even as the moon rises, however, it will be sitting low in the east. If possible, find a hedgerow of trees, a barn or some such thing to block out the moon. Sit in a moon shadow but at the same time, find an expansive view of sky. Or simply look away from the moon. The key to watching meteors is to find an open sky, away from pesky artificial lights. Lie down in comfort, perhaps snuggled up in a warm sleeping bag, and look upward.

The Geminid meteors radiate from near star Castor in Gemini.

The Geminid meteors radiate from near the star Castor in Gemini.

Meteor flying straight from Gemini's two brightest stars, Castor and Pollux, on night of December 12-13, 2012.  Photo by EarthSky Facebook friend Mike O'Neal in Oklahoma.  Thank you Mike!

Meteor flying straight from Gemini’s two brightest stars, Castor and Pollux, on night of December 12-13, 2012. Photo by EarthSky Facebook friend Mike O’Neal in Oklahoma. Thank you Mike!

Why are these meteors called the Geminids? If you trace the paths of the Geminid meteors backward, they all seem to radiate from the constellation Gemini, hence the reason for the meteor shower’s name.

In fact, the radiant point of this meteor shower nearly coincides with the bright star Castor. However, the radiant point and the star Castor just happen to be a chance alignment, as Castor lies about 52 light-years away while these meteors burn up in the upper atmosphere, some 100 kilometers (60 miles) above the Earth’s surface.

You don’t need to find the constellation Gemini to watch the Geminid meteor shower. These medium-speed meteors streak the nighttime in many different directions and in front of numerous age-old constellations. It’s even possible to see a Geminid meteor when looking directly away from the shower’s radiant point. However, if you trace the path of any Geminid meteor backward, it’ll lead you back to the constellation Gemini the Twins.

How to find Gemini, the radiant point of the Geminid shower. It’ll be especially easy to locate this constellation on December 7, 2014, should you want to see it. That’s because the moon beams right in front of Gemini and shines close to Gemini’s brightest stars, Castor and Pollux on this date.

Jupiter and the constellation Gemini climb into the east-northeast sky by early-to-mid-evening in December 2013.

On the moonless evening of December 3, 2013, Chris Georgia took this gorgeous photo of the constellation Orion (above his head and left of the light pole), the planet Jupiter (brightest star-like object at left), and the Gemini stars to upper left of Jupiter: Castor (at top) and Pollux (at bottom). Thank you so much, Chris! View larger

On the moonless evening of December 3, 2013, Chris Georgia took this gorgeous photo of the constellation Orion (above his head and left of the light pole), the planet Jupiter (brightest star-like object at left), and the Gemini stars to upper left of Jupiter: Castor (at top) and Pollux (at bottom). Thank you so much, Chris! View larger

Have you been watching the blazing planet Jupiter, the king planet, rising in the east by mid-to-late evening? Expect the Geminid meteors to intensify as Jupiter rises higher in the sky. Click here for recommended sky almanacs. They can help you find when Venus sets and Jupiter rises into your sky.

Painting of 1860 earthgrazer fireball by Frederic Edwin Church. Image credit: Wikimedia Commons

Painting of 1860 earthgrazer fireball by Frederic Edwin Church. Image credit: Wikimedia Commons

An earthgrazer meteor possible at early evening. You won’t see as many Geminid meteors before Jupiter enters the sky, or when the constellation Gemini still sits close to the eastern horizon. Even so, the early evening hours present an opportune time to try to catch an earthgrazer meteor.

Earthgrazers are rarely seen but prove to be especially memorable, if you should be lucky enough to catch one. An earthgrazer is a slow-moving, long-lasting meteor that travels horizontally across the sky. As the constellation Gemini, the radiant point of the Geminid meteors, climbs upward throughout the evening hours, the meteors will cross the sky less horizontally and will rain down from a point that’s higher in the sky.

Once Gemini and Jupiter make their appearance, they’ll be out for rest of the night. The Gemini stars Castor and Pollux reach their highest point for the night around 2 a.m. local time and Jupiter about two hours thereafter. As a general rule, the higher the constellation Gemini climbs into your sky, the more Geminid meteors that you’re likely to see.

Orbit of Asteroid 3200 Phaethon, parent of the Geminid meteor shower

The orbital path of asteroid 3200 Phaethon, and the four inner planets of the solar system: Mercurio (Mercury), Venere (Venus), Terra (Earth) and Marte (Mars). Image credit: Wikimedia Commons

The orbital path of asteroid 3200 Phaethon, and the four inner planets of the solar system: Mercurio (Mercury), Venere (Venus), Terra (Earth) and Marte (Mars). Image credit: Wikimedia Commons

What causes the Geminid meteor shower? Every year, in December, our planet Earth crosses the orbital path of asteroid 3200 Phaethon, a mysterious body that is sometimes referred to as a rock comet.

In periods of 1.43 years, this small 5-kilometer (3-mile) wide asteroid-type object swings extremely close to the sun (to within one-third of Mercury’s distance), at which juncture intense thermal fracturing causes this rocky body to crack and crumble, and to shed rubble into its orbital stream. Annually, at this time of year, the debris from 3200 Phaethon crashes into Earth’s upper atmosphere at some 130,000 kilometers (80,000 miles) per hour, to vaporize as colorful Geminid meteors.

How to watch the Geminid meteors. Why not give the Geminid meteor shower a try? You need no special equipment – just an open view of sky away from pesky artificial lights. Sprawl back in a hammock or a pile of hay, and look upward to witness one of the finest sky attractions of the year: the Geminid meteor shower!

Be sure to give yourself at least an hour of observing time. It takes about 20 minutes for your eyes to adapt to the dark, and moreover, meteors often come in spurts which are interspersed by lulls.

Bottom line: Despite the drenching moonlight in 2014, the reliable Geminid shower is sure to add to the holiday lighting on the nights of December 12-13 and 13-14! This post contains information about the shower’s radiant point, and tips on when and how to watch December’s Geminid meteor shower.