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 136 kilometres 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]