Photo of the Day 24 November 2007

Sky Disk at Twilight, Germany, 2004
Photograph by Kenneth Garrett
Found buried in a hill in the town of Nebra in 1600 B.C., this 3,600-year-old sky disk reflects cloud-strewn skies in central Germany. The disk, which tracks the sun's movements along the horizon, contains the oldest known depiction of the night sky and may have served as an agricultural and spiritual calendar.