Just as a 3-D movie combines two similar but slightly different images to form a three-dimensional image, this snapshot of the Saturnian moon Prometheus
is actually two photos in one.
The composite consists of two black-and-white images that were captured from different angles on December 26, 2009. Red-blue glasses--the kind worn to view 3-D movies--reveal a lifelike picture of Prometheus. Long and thin, this moon measures about 90 feet in length, and its uneven surface is rife with craters. Its low density has led scientists to speculate that it may consist of porous, icy material.