Astronomy Picture of the Day

Explanation: What’s happening in the sky over Monument Valley? A meteor shower. Over the past weekend the Leonid meteor shower has been peaking. Now the Leonids peaks every year in mid-November. The above image -- actually a composite of six exposures of about 30 seconds each -- was taken in 2001, a year when there was a more active Leonids shower. At that time, Earth was moving through a particularly dense swarm of sand-sized debris from Comet Tempel-Tuttle, so that meteor rates approached one visible streak per second. All of the above meteors appear parallel because they all fall to Earth from the meteor shower radiant -- a point on the sky towards the constellation of the Lion (Leo). Although the peak of this year's Leonid meteor shower peak is over, an abundance of Leonids meteors should still be visible over the coming week. By the way -- how many meteors can you identify in the above image?