Google an image of Saturn and your attention will immediately turn to the planet’s rings—the famous halo of space debris that consists of nine continuous main rings and three discontinuous arcs. Look deeper, and you’ll notice something unusual: pictures of the planet never feature any stars. What gives?
A new explanation from NASA reveals the rings are simply too bright for any stars to appear in photos of the planet. It’s an obvious explanation but probably something you never really thought about.
“Saturn’s main rings are much brighter than most stars,” NASA said. “As a result, much shorter exposure times (10 milliseconds, in this case) are required to produce an image and not saturate the detectors of the imaging cameras on NASA’s Cassini spacecraft. A longer exposure would be required to capture the stars as well.”
NASA’s Cassini spacecraft has captured stars before, which you can see in an image of Saturn’s moon Enceladus, which was in eclipse at the time the picture was taken.
Photos of Saturn always make it look like the planet is in the depths of space’s deepest, darkest caverns. But it turns out the rings are just so bright that capturing them and any stars around it prove to be too intense for Cassini’s cameras to handle.