Pushing and Pulling
July 30, 2010
Rather than being an unchanging disk of peaceful particles, the material that makes up Saturn’s rings is constantly pushed and pulled into spectacular shapes.
On the left of the image, the moon Daphnis (8 kilometers,or 5 miles across) affects material as it orbits in the A ring’s Keeler Gap. The moon’s orbit is inclined relative to the plane of Saturn’s rings. Daphnis’ gravitational pull perturbs the orbits of the particles forming the Keeler Gap’s edge. This sculpts the edge into waves having both horizontal (radial) and out-of-plane components. Material on the inner edge of the gap orbits faster than the moon so that the waves there lead the moon in its orbit. Material on the outer edge moves slower than the moon, so waves there trail the moon.