Celestial News: Get ready for Geminid meteor shower | SteamboatToday.com

Celestial News: Get ready for Geminid meteor shower

The annual Geminid meteor shower is rising this week toward its peak of activity next weekend. Geminid meteors seem to spring from our constellation of Gemini, the Twins, and streak across the sky in all directions. Watch for Geminid meteors any time between 8 p.m. and dawn, with the hours from midnight to dawn being the most active. In this image, taken Dec. 14, 1985 from Brasstown Bald Mountain in northern Georgia, a bright Geminid meteor left its long streak across the one-hour time exposure.
Jimmy Westlake/courtesy

Wow! Did you see that? Look — there goes another one!

Get ready for the best meteor shower of the year. It’s the Geminid meteor shower, and it could bring as many as 120 shooting stars per hour to our sky. The Geminid meteor shower almost always makes my Top 10 list of don’t-miss celestial events each year.

Geminid meteors are so named because they seem to spring from our constellation of Gemini, the Twins.

Each bright streak you see is caused by a tiny bit of space dust entering the Earth’s atmosphere at high speed and burning up at an altitude of about 60 miles. Most of the particles are so small you could hold a thousand of them in the cupped palm of your hand. Under ideal, dark sky conditions, a single observer can expect to see as many as 120 meteors per hour on the morning of peak activity and fewer on either side of the peak.

First observed in the year 1862, Geminid meteors are unique for a number of reasons, foremost of which is their unusual source. Most other meteor showers are produced by fluffy little pieces of comet dust, but Geminid meteors are tough little bits of rock, shed by a rocky asteroid named Phaethon.

Once every 17 months, Phaethon makes a close pass by the Sun, inside the orbit of the planet Mercury. This causes its parched surface to crack, fracture and spew dusty particles into space. For this unusual behavior, Phaethon has been described as a “rock comet.” Earth plows through Phaethon’s dust-filled orbit in mid-December each year and, as a result, we are treated to the Geminid meteor shower. Because the particles from Phaethon are rocky, they can penetrate deeper into Earth’s atmosphere before burning up, so Geminid meteor streaks tend to be long, slow and bright.

This year, the 2.5-day-old crescent moon will set early in the evening, so meteor watching can begin as early as 8 p.m. the night of Dec. 13-14, when the constellation of Gemini breaks the northeast horizon. In general, the meteor counts tend to increase in the hours after midnight as Gemini rises higher in our sky.

Geminid meteors can be seen for several nights before and after the peak, so take advantage of any clear night this week and next. In fact, the biggest, brightest Geminid fireballs tend to show up in the nights right after the night of the peak activity.

If you have a tripod-mounted camera and are feeling lucky, you might be able to record the streak of a bright Geminid meteor. Use a wide angle lens to capture as large a patch of sky as possible and set to a low aperture setting to let in as much light as possible. Set your digital camera’s ISO sensitivity to at least 800, mount it on a stable tripod and then take brief time exposures of the sky. If the Moon is not in the sky, you can try exposures of 30 seconds as many as several minutes.

Geminid meteors will shoot across all parts of the sky, so it won’t really matter where you aim your camera. If you are lucky, one or more bright meteors might shoot through your chosen patch of sky.

So, bundle up against the cold, grab a thermos of your favorite warm beverage and get out there beneath the stars to watch Mother Nature’s free holiday fireworks show — the annual December Geminid meteor shower.

Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper and his “Cosmic Moment” radio spots can be heard on local radio station KFMU. Check out Jimmy’s new “2016 Cosmic Calendar” of sky events on his website at jwestlake.com. It features 12 of his best sky photos and a day-by day listing of cool celestial events that you and your family can enjoy watching in 2016.

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