关于这张图
Saturn's innermost moon Pan orbits the giant planet seemingly alone in a ring gap its own gravity creates. Pan (17 miles, or 28 kilometers across) maintains the Encke Gap in Saturn's A ring by gravitationally nudging the ring particles back into the rings when they stray in the gap. Scientists think similar processes might be at work as forming planets clear gaps in the circumstellar disks from which they form. This view looks toward the sunlit side of the rings from about 38 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on …
