Four of Saturn’s 62 moons are seen passing each other in this animation, composed from 22 raw images taken by the Cassini spacecraft on July 27, 2010. Epimetheus, Prometheus, Janus and tiny Atlas all orbit Saturn within or near the ring system. As the animation begins, the potato-shaped Prometheus is just “rounding the bend” inside the edge of the thin F ring, making it appear to stand still for a moment before continuing on toward the right. Janus and Epimetheus appear to switch places as they pass each other, except that one is on the near side of the rings and the other on the far side. An interesting little vignette of the dynamics of Saturn’s family of moons!
Image: NASA/JPL/Space Science Institute. Animation by J. Major.