This may just be another glorious picture of Saturn's rings -- but it also serves to show just how large the planet is. Can you make out its moon Prometheus in the image?
Down in the lower left-hand corner, there's a bright white spot. It's not a broken pixel on your screen, but Saturn's moon, Prometheus. Discovered in 1980, the small, elongated moon -- it measures 136km along one axis, but only 79 and 59 along the other -- orbits the planet just within Saturn's outermost F ring. Thought to be a porous, icy body, it's actually small enough that its orbit is strongly influenced by nearby rings and moons. [NASA]