Saturn's mysterious hexagon has changed from blue to gold - and no one knows why - ScienceAlert
'It’s like nothing we’ve seen on any other planet in the entire Universe, and now the mysterious structure on Saturn’s north pole just got even weirder.
In just four years, Saturn’s hexagon has changed its colour from blue to gold. So far, our best guess as to why this change occurred is that this is what it looks like when Saturn's north pole gears up for next year's summer solstice.'http://www.sciencealert.com/saturn-s-mysterious-hexagon-has-changed-from-blue-to-gold-and-no-one-knows-whyCatalog Page for PIA21049
'... Scientists are investigating potential causes for the change in color of the region inside the north-polar hexagon on Saturn. The color change is thought to be an effect of Saturn's seasons. In particular, the change from a bluish color to a more golden hue may be due to the increased production of photochemical hazes in the atmosphere as the north pole approaches summer solstice in May 2017.
Researchers think the hexagon, which is a six-sided jetstream, might act as a barrier that prevents haze particles produced outside it from entering. During the polar winter night between November 1995 and August 2009, Saturn's north polar atmosphere became clear of aerosols produced by photochemical reactions -- reactions involving sunlight and the atmosphere. Since the planet experienced equinox in August 2009, the polar atmosphere has been basking in continuous sunshine, and aerosols are being produced inside of the hexagon, around the north pole, making the polar atmosphere appear hazy today.
Other effects, including changes in atmospheric circulation, could also be playing a role. Scientists think seasonally shifting patterns of solar heating probably influence the winds in the polar regions.