Saturn‘s North Polar hexagon has changed color from blue to gold – and no one knows why.

Astronomers noticed a change in color of Saturn’s hexagonal polar storm, from a bluish to a golden hue.

This may be due to the “increased production of photochemical hazes in the atmosphere” as it approaches summer solstice in May 2017.

Above, both images were taken by the Cassini wide-angle camera.  Credit NASA/JPL-Caltech/Space Science Institute/Hampton University

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.

source photojournal.jpl