The Geminid meteor showers, which get their name from the constellation of Gemini, take place during the second week of December each year and peak on December 13th. Unlike the Perseids and the Leonids, which have been observed for hundreds or thousands of years, the Geminid meteors seemed to have appeared suddenly in the mid-1800's. They were first discovered in 1862, when 10-20 shooting stars were seen per hour. Since then, the Geminids have grown in intensity, and today they are one of the most spectacular meteor showers. In years in which the skies are clear and moonless on December 13th, over 100 shooting stars can be seen per hour at the peak of the Geminid shower.
Since the discovery of the Geminids, astronomers have been searching for the parent comet that causes the phenomenon, since most meteor showers are the result of debris that comes off of comets as they pass close to the sun. In 1983, NASA determined that the source of the Geminids is 3200 Phaethon, which is either a comet or a rocky asteroid. If Phaethon is a comet, the meteors would be created when it passes close enough to the sun to heat its frozen nucleus; if Phaethon is an asteroid, however, the mechanism by which the meteorites are formed is less clear. Many astronomers believe that Phaethon is an extinct or dormant comet that has accumulated a thick crust of interplanetary dust. For this reason, it may look like an asteroid but behave like a comet.
Last updated: December 12, 2004.
