File:Saturn's Daphnis Pulls Rings (4046388581).jpg

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Ring material pulled to spectacular heights above the ring plane by the gravity of the moon Daphnis casts long shadows on Saturn's A ring in this Cassini image taken about a month before the planet's August 2009 equinox. The shadows in this image have lengths as long as 500 kilometers (310 miles), meaning the structures casting the shadows reach heights of almost 4 kilometers (2.5 miles) above the ring plane. Daphnis (8 kilometers, or 5 miles, across) is a bright dot in the Keeler Gap of the A ring on the right of the image. Its gravitational pull perturbs the orbits of the particles of the A ring forming the Keeler Gap's edge and sculpts the edge into waves. 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. The thin F ring on the left of the image shows the perturbations caused by the moon Prometheus.