Shepherd Moon Face-Off!

Raw Cassini image acquired on Dec. 18, 2012 (NASA/JPL/SSI) Two of Saturn’s shepherd moons face off across the icy strand of the F ring in this image, acquired by the Cassini spacecraft on December 18, 2012. In the left corner is Pandora, external shepherd of the ropy ring, and in the right is Prometheus, whose [...]