Sir Isaac Newton would be amazed by this awesome video, showing Saturn moons causing waves as they orbit near its F Ring. These images can only be taken every 15 years, during Saturn's equinox. Thankfully, Cassini is there now.
Check out that flat shadow crossing Saturn's rings. It's the shadow of Mimas, one of Saturn's moons, and its appearance means we're getting closer to Saturn's equinox, when it'll be spring in the North and the rings will go dark.