December 9, 2010
Skywatchers To Enjoy A Winter Geminid Treat
On the evening of Dec. 13 and the morning of Dec. 14, skywatchers across the northern hemisphere will be looking up as the Geminid meteor shower reaches its peak, in one of the best night sky events of the year. And unlike many astronomical phenomena, meteors are best seen without a telescope (and are perfectly safe to watch).
At its peak and in a clear, dark sky up to 100 'shooting stars' or meteors may be visible each hour. Meteors are the result of small particles entering the Earth's atmosphere at high speed, burning up and super-heating the air around them, which shines as a characteristic short-lived streak of light. In this case the debris is associated with the asteroidal object 3200 Phaethon, which many astronomers believe to be an extinct comet.
The meteors appear to originate from a 'radiant' in the constellation of Gemini, hence the name Geminid. By 0200 GMT on 14 December the radiant will be almost overhead in the UK, making it ideally placed for British observers. By that time the first quarter Moon will have set so the prospects for a good view of the shower are excellent.
Meteors in the Geminid shower are less well known, probably because the weather in December is less reliable. But those who brave the cold can be rewarded with a fine view. In comparison with other showers, Geminid meteors travel fairly slowly, at around 35 km (22 miles) per second, are bright and have a yellowish hue, making them distinct and easy to spot.
This year the peak of the Geminids meteor shower occurs at around 1100 GMT on 14 December, but the highest level activity is spread over a period lasting a day or more. This means that if conditions are clear it is worthwhile observing at any time between Sunday night and Wednesday morning.
As with most astronomical events, the best place to see meteors is at dark sites away from the light pollution of towns and cities. In good weather, rural sites such as Galloway Forest Dark Sky Park in Scotland (where a planned meteorwatch will take place on 13-14 December) are potentially excellent locations to see the Geminid shower.
The Geminids will also feature in a Twitter event supported by the Royal Astronomical Society (RAS) where observers under clear skies can post their text, images and videos to share them with those in less favorable locations. Anyone with Internet access can join in by following @virtualastro and the #meteorwatch hashtag on Twitter.
Image Caption: An all-sky image of the 2004 Geminids meteor shower. Credit: Chris L. Peterson, Cloudbait Observatory
On the Net:
- Royal Astronomical Society
- International Meteor Organisation (includes a calendar of meteor activity and information on the 2010 Geminids)
- Meteorwatch project (includes an article by Steve Owens on the prospects for this year's Geminid shower)