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| | Astronomy Essentials | Space on Dec 14, 2014

Everything you need to know: Geminid meteor shower

Peak viewing was Saturday night, but, if you look in a dark sky late Sunday until dawn Monday, you might still catch a stray Geminid.

The peak night of the 2014 Geminid meteor shower was probably last night (evening of December 13 through dawn on December 14). Can you still see Geminid meteors tonight (evening of December 14 through dawn on December 15)? Maybe! Different sources will give different times for the peak, but a source we trust – Observer’s Handbook from the Royal Astronomical Society of Canada – gives the peak as 12 UTC (6 a.m. CST) on December 14. That means that, when night falls Sunday evening, we’re still fairly near the peak. By all reports, this year’s shower is a good one! We’ve received some beautiful photos, which you can see here. Geminid meteors tend to be few and far between at early evening, but intensify in number as evening deepens into late night. The moon is waning and will be less prominent in the sky Monday morning than Sunday morning. Geminid meteors are bright! They can withstand some moonlight. This shower favors Earth’s Northern Hemisphere, but it’s visible from the Southern Hemisphere, too. Follow the links below to learn more about the Geminid meteor shower in 2014.

See it! Best photos of 2014’s Geminid meteor shower

Moonlight a factor in Geminid shower in 2014

How to watch the Geminid meteors

An earthgrazer Geminid meteor possible at early evening

Why are these meteors called the Geminids?

What causes the Geminid meteor shower?

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. In a year when moonlight doesn’t obscure the view, you can easily see 50 or more Geminid meteors per hour on the peak night. However, in 2014, the waning moon will dampen the display somewhat in the peak viewing hours.

Don’t let the moonlight discourage you. A good percentage of these yellow-colored Geminid meteors are quite bright and will overcome the moonlit skies.

Of course, you can always watch this shower during the evening hours before moonrise. That’s the best time to catch an earthgrazer … more about that below.

The moon will rise quite late on December 13 and 14, creating a window of darkness for watching the Geminid shower in the evening. On the morning of December 15, the moon will rise later still. 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 Geminid meteors radiate from near star Castor in Gemini.

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

How to watch the Geminid meteors. The December Geminids are a particularly reliable and prolific shower, one of the finest of the year. In 2014, the peak night is probably the night of December 13 (morning of December 14). Try the night before (December 12-13), and the night after (December 14-15), too.

You need no special equipment – just a dark, open sky and maybe a sleeping bag to keep warm. Plan to sprawl back in a hammock, lawn chair, pile of hay or blanket on the ground. Lie down in comfort, and look upward.

Your local peak will typically be centered at about 2 a.m. local time, no matter where you are on the globe. That’s because the constellation Gemini – radiant point of the shower – will reach its highest point for the night around 2 a.m. (your local time). As a general rule, the higher the constellation Gemini climbs into your sky, the more Geminid meteors you’re likely to see.

Some people mistakenly think that, since meteor showers have radiant points, you should look in the direction of the shower’s radiant point to see the most meteors. Not so! The meteors will appear in all parts of the sky.

It’s fun to bring along a buddy. Then two of you can watch in different directions. When someone sees one, they can call out “meteor!” This technique will let you see more meteors than one person watching alone will see.

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.

Be aware that meteors often come in spurts, interspersed by lulls.

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 when the constellation Gemini sits close to the eastern horizon during the evening hours. As night passes, the Geminid’s radiant will climb upward, so that the meteors will be raining down from a point that’s higher in the sky.

Even so, the evening hours are the best 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.

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, during the 2012 Geminid meteor shower. 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.

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.

Bottom line: Despite the moonlight in 2014, the reliable Geminid shower is sure to add to the holiday lighting on the nights of December 12-13, 13-14 and 14-15! This post contains information about the shower’s radiant point, and tips on when and how to watch December’s Geminid meteor shower.