this friday, december 14th, 2007, peaks the last and best meteor shower of the year!! start looking up late each night this week to see a few cosmic fireballs streaking across the sky, but friday night provides the best show! starting after 10pm, local time, look to the left of the constellation orion, toward mars and the constellation gemini. after midnight, you might be able to see a dozen "shooting stars" each hour... and the moon will be just past new so the sky will be dark!
astronomers first noticed the geminids (relatively recently) in 1862, but didnt realize their unusual origin until 1983. all other meteor showers are caused by earth passing through the dusty remains of a comet tail, as we saw for the orioids meteor shower in october. the geminids originate from earth's orbit passing thru a place in space where the near earth object, 3200 Phaeton, passed. this object is classified as an asteroid, which does not have the debris tails that cause comets to leave behind stuff that evaporates in earths atmosphere. here's an image of a comet (hale-bopp) and an (up close) asteroid (951 gaspra) so you can see the lack of loose stuff around an asteroid!
so what has happened to cause the geminids? the theory is a bit controversial, but many believe that 3200 Phaeton is the central rocky remains of what was once a comet! the orbit of 3200 phaeton is elliptical and passes very close to the sun, which are characteristics of comets, not asteroids. you can read more from NASA, but in the meantime... enjoy!!
(the first photo of the geminids was taken by Fred Bruenjes in 2004.)