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From high above Saturn's northern hemisphere, NASA's Cassini spacecraft gazes over the planet's north pole, with its intriguing hexagon and bullseye-like central vortex. Saturn's moon Mimas is visible as a mere speck near upper right. At 246 miles (396 kilometers across) across, Mimas is considered a medium-sized moon. It is large enough for its own gravity to have made it round, but isn't one of the really large moons in our solar system, like Titan. Even enormous Titan is tiny beside the mighty gas giant Saturn. This view looks toward Saturn from the sunlit side of the rings, from about 27…
