It’s the finale of this year’s meteor showers: The Geminids will start appearing on Dec. 7 and should reach peak activity around the 13th and 14th. This shower could put on a display of up to 100+ meteors (shooting stars) per hour under good viewing conditions.There is something unusual about the Geminid meteor shower, as normally meteor showers are caused by the Earth ploughing through the debris streams created by comets and their tails. But the object that created the specific stream of debris associated with the Geminids is not a dusty icy comet, but a rocky asteroid called Phaethon 3200.
Phaethon 3200 belongs to a group of asteroids whose orbit cross the Earth’s. It turns out to be an unusual member of that group: Not only does it pass closer to the Sun than the others but it also has a different colour, suggesting a different composition to most asteroids.
Ten tips for watching the Geminid meteor shower1. The Geminids are one of the year’s best annual meteor showers. On a dark, moonless night, the Geminids often produce 50 or more meteors per hour, or nearly a meteor a minute. In 2011, the moon is in the way. You might have to settle for a single bright meteor or two – more, if you watch over several hours – streaking along in bright moonlight.
2. Dark skies away from the glare of city lights are important, even on a moonlit night For optimum viewing, find a place to observe in the country.
3. The 2011 Geminid meteor shower will be better if you work around the moon. Try watching before moonrise. Click on this custom sunrise/sunset calendar for moonrise and moonset times (be sure to check the appropriate boxes). After moonrise, try to shade yourself from the moon’s light. Sit in the shade of a house, tree or mountain – but leave an otherwise open view of sky.
4. If you were to track the Geminid meteors backwards on the sky’s dome, you’d find them streaming from a point in the sky within the boundaries of the constellation Gemini the Twins. Hence this shower’s name. The Geminid radiant point climbs over the eastern horizon before the moon does – around 7 p.m. local time for our mid-northern latitudes. The early rising time for the radiant point is why the Geminid shower is one of the few meteor showers worth watching in the evening hours. That’s good! Because there will be a narrow window of darkness after sunset and before moonrise.
Meteor showers are fun for families and friends. Via Cumbrian Sky
5. The Geminid radiant point lies close to a noticeable bright star – one of the Gemini “twins” – the star Castor. You don’t need to know Castor or the constellation Gemini to enjoy the Geminid meteor shower. All you need is an open view of the sky. But the Geminids will streak through many different constellations, and a moonlit night is a better time for learning constellations than a moonless one – because faint stars are drowned from view. So try learning a constellation or two. Many people find a star wheel very helpful.
6. In 2011, check out the planets. Five bright planets in the December 2011 sky are so bright that the moon won’t bother them at all. Venus and Jupiter are in the evening sky, and you can’t miss them. They are the two brightest objects up when the sun goes down. You can watch for the red planet Mars to rise in the east shortly before midnight. Watch Saturn rise around 3 a.m., at about the time that Jupiter sets. Just before dawn, the innermost planet Mercury climbs above the sunrise point on the horizon. Need help? Try EarthSky’s December 2011 guide to the visible planets.
Meteor photo via Ursi's Eso Garden. Image Credit: Antonio Finazzi
7. Most meteors in annual showers originate in comets. But the parent of the Geminid meteor shower is a mysterious body named 3200 Phaethon. This solar system object is termed an Apollo (near-Earth) asteroid, and it might be a dormant comet. How does that help you watch the shower? It doesn’t. But it’s fun to think about.
8. The best way to watch meteors is to bring along a buddy. Both of you watch different parts of the sky. If one of you sees one, shout out “meteor!” If you don’t know which way to look, don’t worry. Just let your eyes rove casually in all parts of the sky.
9. Special equipment? Not necessary. You only need a dark sky, a reclining lawn chair and the warmth of a sleeping bag. A hot drink is also good. Just remember. Watching a meteor shower is not like turning on the television. You can’t expect to just look out the window, or simply step outside to see meteors. Your eyes take some 20 minutes to dark-adapt. If you’re serious about it, give yourself at least an hour of viewing time. Even the best meteor showers have lulls and spurts.
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