Saturn’s innermost moon, Pan, appears to be just a tiny dot circling a much bigger world. But the 17-mile-wide object shaped like a flying saucer has an outsized effect on Saturn’s rings. Ring particles are swept aside by the moon’s gravity, resulting in a 200-mile-wide break in the rings known as the Encke Gap. The moon also leaves a mark on the rings themselves. Ring particles closer to Saturn orbit faster than Pan. As they pass the moon, Pan gives them a gravitational boost that bunches up the particles and sets off cascading ripples through the rings. Explore the images for views of Pan and Saturn’s rings taken by NASA’s Cassini spacecraft.