It is time once again for the annual Geminid meteor shower – often the best meteor shower of the year - which peaks late Sunday night into early Monday (Dec 13th-Dec 14th). The Earth is now entering a stream of debris from the “rock comet” officially named “3200 Phaethon”. If viewing conditions are favorable (so-so outlook on that) then there could be as many as 120 meteors per hour. Overall observing conditions this year are very favorable because the meteor shower peaks just a few days after the New Moon unlike last year at which time a nearly full moon produced much in the way of light interference.
Most meteor showers are caused by comets, but the Geminid meteor shower is somewhat mysterious in that “3200 Phaethon” is kind of a strange rocky object that was discovered in 1983. In fact, many references to “3200 Phaethon” simply use the term “asteroid” as a way of description, but others use the phrase “rocky comet” which is a new kind of object cited by some astronomers. They define a “rocky comet” as essentially, an asteroid that comes very close to the sun--so close that solar heating scorches dusty debris right off its rocky surface. Rock comets could thus grow comet-like tails made of debris that produce meteor showers on Earth.
Earth runs into this stream of debris from “3200 Phaethon” every year in mid-December causing meteors to fly from the constellation Gemini – hence the name Geminids. The Geminid meteor shower does not only produce numerous shooting stars, but it is also known to produce some unusual colors as they streak across the sky. The color of light that the meteors produce depends on their chemical composition. Different chemicals produce different colors as they burn up while moving through the Earth’s atmosphere (above). The best time to view should be in the wee hours of early Monday morning – depending, of course, on cloud cover.
Meteorologist Paul Dorian