WISE satellite measures girth of Saturn’s widest ring

Saturn’s rings reach farther than the eye can see — and astronomers now know just how far that is. The outermost band of dust, best seen in infrared light, is at least 270 times as wide as the giant planet, researchers report in the June 11 Nature.

The nearly invisible belt, first detected in 2009, appears to be fed by debris chipped off the tiny moon Phoebe. Researchers weren’t able to measure the full extent of the dark ring then. More recent images from the infrared WISE satellite, however, let planetary scientist Douglas Hamilton, of the University of Maryland in College Park, and colleagues get a better look.