Dark and sharply defined ring shadows appear to constrict the flow of color from Saturn’s warmly hued south to the bluish northern latitudes.
NASA Voyager spacecraft flybys witnessed a more evenly painted planet in the early 1980s, when Saturn was closer to equinox. Scientists studying Saturn are mystified by the color change from north to south. However, the bluish color was readily apparent upon Cassini’s approach to the planet in late 2003, when Saturn was just coming out of its northern hemisphere winter. Scientists have speculated that the color is due to seasonal effects on the atmosphere.
Aside from the color differences, the cloud morphology is quite different in the polar regions compared to the mid-latitudes. Bright, isolated clouds dot the high latitudes, while Saturn’s middle is characterized by flowing cloud bands and the occasional bright or dark vortex.Image credit: NASA/JPL/Space Science Institute