One of the most prolific annual meteor showers makes its appearance in mid-December. The Geminid shower peaks the night of December 13/14. Although many people consider it to be a poor cousin to August’s Perseid shower, the Geminids often put on a better show. This year, observers can expect to see upward of 100 “shooting stars” per hour — an average of nearly two per minute — under a dark sky.“Conditions should be wonderful for the Geminids this year,” says Astronomy magazine senior editor Michael Bakich. “The First Quarter Moon sets around midnight local time, leaving the prime viewing hours after midnight free from any unwanted natural lighting.” The only potential drawback is cloud cover, which, unfortunately, tends to be fairly common this time of year. Rates for this shower remain decent a day on either side of the peak, so target the morning of December 13 or 15 if the weather looks bad on the 14th.Any stray light in the sky tends to drown out fainter meteors, so find an observing site far from the lights of the city. A large field is ideal because you then can let your eyes roam across the whole sky. December nights tend to be cold, however, so bundle up in layers. Reclining in a lawn chair is a great way to take in a lot of the sky at once, but be sure to get up and walk around occasionally. It also helps to drink some hot coffee or tea.The Geminids begin as tiny specks of dust that hit Earth’s atmosphere at 78,000 mph (126,000 km/h), vaporizing from friction with the air and leaving behind the streaks of light we call meteors. The meteors appear to radiate from the constellation Gemini the Twins (hence their name), near the bright stars Castor and Pollux. This spot, called the radiant, remains visible all night and passes nearly overhead around 2 a.m. local time. Although the meteors seem to originate in Gemini, they can appear anywhere in the sky and actually leave longer trails the farther they are from the radiant.
- The dust particles that create the Geminids don’t originate in a comet, as those in most meteor showers do. Studies of Geminid meteors show these particles coincide with the orbit of an asteroid called Phaethon. Perhaps this object was once a comet that passed through the inner solar system so many times that it lost all of its ices, leaving behind a rocky object that only appears to be an asteroid.
- Although 78,000 mph may seem fast, Geminid meteors are slower than those in most other annual showers. The speed champions are the Leonids of November, which hit our atmosphere at 159,000 mph (256,000 km/h).