Changing Seasons

Images snapped by the Cassini spacecraft in 2013 (left) and 2017 show changing colors at the north pole of Saturn, the solar system's second-largest planet. The image at left was snapped during the middle of spring in Saturn's northern hemisphere, when the north pole was just emerging into the sunlight. The image at right was taken shortly before northern summer arrived on May 24. Ultraviolet light from the Sun zaps molecules in Saturn's atmosphere, forming the yellowish haze. The vortex at the center of the polar region may have stayed blue because the atmosphere spirals into it, clearing away the haze. Upper-level winds sculpt the clouds around the pole into a hexagon that's wider than Earth. The images show Saturn's natural colors. (Click to see an animated version.) [NASA/JPL/SSI/Hampton University]