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Geminid meteors in moonlight

On the nights of December 11 and 13, 2016, you might see some meteors as the 2016 Geminid meteor shower picks up steam. The peak comes Tuesday night – the night of December 13 – but these nights might be a good time to watch, too. Just know that the best viewing hours are typically in the wee hours after midnight (around 2 a.m.), no matter where you are on Earth. In the Northern Hemisphere, this meteor shower often rates as one of the best – if not the best – shower of the year on a dark, moonless night. You can often see as many as 50 or more meteors per hour But this year, in 2016, the full moon occurs on the same date as the shower’s peak. The optimal viewing night on December 13-14 will be under the glaring night of a supermoon, which is sure to reduce the count this year. Follow the links below to learn more:

For the Southern Hemisphere

What time should I watch?

How many meteors will I see?

Why are they called the Geminids?

Where do the meteors come from?

What else should I look for?

Image top of post: Royal Astronomical Society

The Geminids radiate from near the bright star Castor in the constellation Gemini, in the east on December evenings.  Learn more about the radiant point for December's Geminid meteor shower.

The Geminids radiate from near the bright star Castor in the constellation Gemini, in the east on December evenings. Learn more about the radiant point for December’s Geminid meteor shower.

For the Southern Hemisphere. At temperate latitudes in the Southern Hemisphere, the number of meteors tend to be lower. The Geminids do favor the Northern Hemisphere, where the radiant is higher in the sky. However, this shower is also visible from the tropical and subtropical parts of the Southern Hemisphere. Watch for it anyway!

What time should I watch? The best time to watch is after midnight, when the radiant point is high in the sky. Watching from midnight until dawn is probably optimum.

If you’re not one to stay up late, watch during the evening hours. Although the meteors are few and far between at early-to-mid evening, you might – if you’re really lucky – catch an earthgrazer – a slow-moving and long-lasting meteor that shoots horizontally across the sky.

At northerly latitudes, the shower radiant point – near the bright star Castor in the constellation Gemini – stays out from early evening until dawn. When the radiant point is near the horizon, the number of meteors that you see are few. The radiant climbs highest up around 2 a.m. and that’s why you see the highest numbers of Geminid meteors around that time.

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 2012’s Geminid meteor shower. Photo by EarthSky Facebook friend Mike O’Neal in Oklahoma.

How many meteors will I see? The Geminids are a consistent and prolific shower. You’ll see the most meteors in a dark sky, unspoiled by light pollution. Meteors often come in spurts and are interspersed by lulls, so give yourself at least an hour of observing time. Simply sprawl out on a reclining lawn chair, look upward and enjoy the show. Often, in the wee hours after midnight, you can see 50 or more meteors per hour. You won’t see as many meteors this year because of the moonlight. But the Geminids tend to be bright, so we expect some Geminid meteors to blaze the sky in spite of the moon.

Why are they called the Geminids? The Geminid meteors are named for the constellation Gemini the Twins, because the radiant point of this shower lies in front Gemini, closely aligning with the bright star Castor. If you trace all the Geminid meteors backward, they all appear to originated from this constellation.

But you don’t need to know the constellation Gemini to see the meteor shower. The Geminid meteors will streak across all parts of the heavens from late night until dawn.

Where do the meteors come from? Although meteors are sometimes called ‘shooting stars,’ they have nothing to do with stars. Instead, they are strictly a solar system phenomenon. Around this time every year, our planet Earth crosses the orbital path of a mysterious object called 3200 Phaethon, which might be an asteroid or a burnt-out comet orbiting our sun. Debris from this object burns up in the Earth’s upper atmosphere to give us the annual Geminid meteor shower. The moderately fast Geminids slice through the Earth’s atmosphere at some 35 kilometers – or 22 miles – per second.

What else should I look for?Look for the dazzling planet Jupiter, the sole morning planet. From all over the world, this world rises around 2 a.m. local time. By a wonderful coincidence, it’s at this time that the Geminid radiant climbs highest in the sky and is likely to produce that greatest number of meteors!

Our friend Tom Wildoner at LeisurelyScience.com wrote:

Our friend Tom Wildoner at LeisurelyScience.com wrote: “Jupiter simply looks awesome early in the morning just coming up through the bare trees of the Broad Mountain here in Carbon County, Pennsylvania. This view was captured about 4:30 AM local time from my backyard in Weatherly, Pennsylvania on December 6, 2016.”

Bottom line: Find a dark sky to watch a seasonal attraction, the Geminid shower. It peaks on the night of December 13, 2016 (morning of December 14), but the nights before and after will feature some Geminid meteors as well. Even though the full moon will obscure this year’s production, we still expect some Geminid meteors to add to the holiday lighting!

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