Saturn’s north pole was dark when Cassini arrived in 2004. But as the seasons changed, light illuminated a bizarre six-sided swirl of gases at the pole (shown here in false color). The hexagon has been known since the 1980s. It is about 30,000 kilometers (18,600 miles) wide with a massive hurricane centered on the north pole.
JPL-CALTECH/NASA, SPACE SCIENCE INSTITUTE