These two natural color images taken by the Cassini spacecraft show how Saturn’s north polar region has changed between 2012 and 2016. The color change is thought to be an effect of Saturn’s seasons. It’s believed that the change from a bluish color to a more golden hue is caused by the increased production of smog in the atmosphere as the north pole approached the summer solstice due in May, 2017.

The hexagon, Saturn’s six-sided jetstream, seems to act as a barrier preventing haze particles produced outside it from entering. If that’s the case, the polar atmosphere becomes clear of aerosols produced by photochemical reactions, reactions caused by sunlight, during the winter darkness. After Saturn’s northern spring equinox, the north pole polar is in continuous sunshine, and smog aerosols can be produced inside the hexagon, making the polar atmosphere appear hazy.

Image Credit: NASA