In this image released by NASA, the south polar vortex at Saturn's moon Titan still stands out against the orange and blue haze layers that are characteristic of Titan's atmosphere. Images like this, from NASA's Cassini spacecraft, lead scientists to conclude that the polar vortex clouds form at a much higher altitude – where sunlight can still reach – than the lower-altitude surrounding haze. (Photo by AFP Photo/NASA/JPL-Caltech/Space Science Institute)
