Behold: a vast hexagonal cloud formation over Saturn’s northern hemisphere. First discovered by Voyager in the 1980s and subsequently observed by Cassini, nothing like it has been found elsewhere in the solar system. To wit:
Acquiring its first sunlit views of far northern Saturn in late 2012, the Cassini spacecraft’s wide-angle camera recorded this stunning, false-colour image of the ringed planet’s north pole. The composite of near-infrared image data results in red hues for low clouds and green for high ones, giving the Saturnian cloudscape a vivid appearance. This and similar images show the stability of the hexagon even 20+ years after Voyager. Movies of Saturn’s North Pole show the cloud structure maintaining its hexagonal structure while rotating. Unlike individual clouds appearing like a hexagon on Earth, the Saturn cloud pattern appears to have six well defined sides of nearly equal length. Four Earths could fit inside the hexagon. Beyond the cloud tops at the upper right, arcs of the planet’s eye-catching rings appear bright blue.