In, Through, and Beyond Saturn's Rings.

Four moons are visible on the featured image -- can you find them all? First -- and farthest in the background -- is Titan , the largest moon of Saturn and one of the larger moons in the Solar System . The dark feature across the top of this perpetually cloudy world is the north polar hood . The next most obvious moon is bright Dione , visible in the foreground, complete with craters and long ice cliffs . Jutting in from the left are several of Saturn's expansive rings , including Saturn's A ring featuring the dark Encke Gap . On the far right, just outside the rings, is Pandora , a moon only 80-kilometers across that helps shepherd Saturn's F ring. The fourth moon? If you look closely inside Saturn's rings, in the Encke Gap , you will find a speck that is actually Pan . Although one of Saturn's smallest moons at 35-kilometers across, Pan is massive enough to help keep the Encke gap relatively free of ring particles. After more than a decade of exploration and discovery, the Cassini spacecraft ran low on fuel in 2017 and was directed to enter Saturn's atmosphere , where it surely melted .