The Geminids above Mobius Arch, Calif.
Most major meteor showers come from passing comets. But some are the result of a nearby asteroid. The Geminid meteors are believed to be from the asteroid 3200 Phaethon, though they look like they are coming from the Gemini constellation. Considered "mysterious" by NASA due to their asteroid parentage, they are seen in December and believed to peak in sightings around mid-month. Pictured here are the Geminids as seen on Dec. 12, 2010, in Alabama Hills, Calif.
NASA notes that the Geminids always put on a good show. Bill Cooke, who leads NASA's Meteoroid Environment Office, predicted that with clear skies, observers could see as many as 40 Geminids per hour in the 2011 Geminid shower.