This infrared image of Saturn's rings, released by NASA on Sept. 2, provides the most detailed temperature map ever taken of the icy particles encircling the planet.
Taken by the Cassini spacecraft on July 1, the false-color image shows the unlit surface of the rings, where temperatures vary from 70 kelvins (blue) to 110 kelvins (red). Water freezes at 273 kelvins. The opaque regions, such as the A ring (outermost green region) and the middle, or B, ring (shades of blue and green) are cooler than the transparent regions, such as the Cassini-division ring, shown in red just inside the A ring, and the innermost, or C, ring, depicted in red.
Temperature differences, evident even within individual rings, arise because the opaque areas let through less sunlight than the transparent regions do.