Comet Wirtanen streaks across a field of stars, as seen through a telescope at the Pik Terskol Observatory in the Russian Caucasus. The observers were T. Credner, K. Jockers and T. Bonev. Wirtanen left behind a trail of debris that may spark a minor meteor shower this week.
The Geminid meteor shower looks as if it'll put on a great show late Thursday night and early Friday morning, but this year's production might turn out to be a double feature: Experts say a new bunch of shooting stars, tentatively known as the Piscids, might make their appearance as a warmup act.
"If it does appear, it will be a minor shower, so people should not expect a major outburst" said Bill Cooke of NASA's Meteoroid Environment Office at Marshall Space Flight Center in Alabama. "The Geminids will dwarf this new meteor shower. They're still the best show."
The Piscids are expected to produce 30 meteors per hour at most, while the Geminids can account for 100 to 120 meteors per hour, Cooke said. There's also a chance that the Piscids will be a non-event.
The Geminid shower is a completely different kettle of fish: It ranks as the year's most reliable meteor shows. The Geminids peak annually on Dec. 13-14 when Earth passes through the trail of cosmic debris left behind by a fizzled-out comet known as Phaeton. Because of the orientation of that debris trail, Geminid meteors appear to come from a point in the constellation Gemini — hence the shower's name.
Based on computer models run by Russian forecaster Mikhail Maslov, the new meteor shower would seem to emanate from a different point in the sky, in the constellation Pisces. The source of the cosmic debris would be Comet Wirtanen, which was discovered in 1948 and takes 5.4 years to orbit the sun. NASA says the comet has skirted Earth's orbit many times, but according to Maslov, this year could mark the first time Earth plows right through Wirtanen's debris trail.
"The meteors from this new shower will be slower-moving than the Geminids," Cooke said. Also, the Piscids are expected to peak before the Geminids. Cooke suggests setting up your meteor-watching post early Thursday evening in case the Piscids show up, and then lingering into the wee hours of Friday for the Geminids' main event.
This year should be particularly good for Geminid watchers, because there'll be no moon in the sky to overwhelm the meteor streaks. "We saw a fair number last night," Cooke said. "I expect they will do about normal this year."
Cooke is getting set to host an Internet chat and live video feed of the Geminids from Marshall Space Flight Center on Thursday night, starting at 11 p.m. ET. He's also reminding people to "stay warm" when they go meteor-watching on a frosty December night.
British astronomer Mark Thompson has lots of good advice about what to wear for winter stargazing at Discovery News, and I'll just add that a thermos of hot beverage (coffee or tea, hot chocolate or soup) goes a long way toward keeping you comfortable amid the chill. You'll want to get to a place with clear, open skies, far away from city lights — and don't expect to see a fireworks show. A meteor shower is a far more subtle affair. My top 10 bits of advice for watching August's Perseid meteor shower work surprisingly well for December's Geminids, and EarthSky.org offers yet another top-10 list of tips.
If you snap a great picture during the Geminids, please consider sharing your gem with the rest of us. You can upload photos via our FirstPerson Web page for sky highlights, and I'll try to pass along some good ones on Friday. Keep a watch on SpaceWeather.com as well.
The mysterious light that flashed over Houston lit up the horizon and sparked debate on social media. NBC's Brian Williams reports.
More about meteors:
- Year's best meteor shower nears its peak
- Superb Geminid meteor shower coming up
- Flash interactive: What causes a meteor show?
- The scientific story behind meteor showers
Tip o' the Log to NASA Science News.
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.