In stark contrast to the brilliant colors of Saturn's rings and the sunlit hydrocarbon seas of Titan, this image taken by the Cassini spacecraft makes them appear as menacing alien worlds. To us, they seem devoid of detail. But to the trained eyes of scientists, such images reveal crucial insights.

High-phase observations — generally taken when cameras are pointed toward the Sun, as in this image — are a potent diagnostic tool for studying atmospheres, which reveal their properties based on how they transmit sunlight. In this example, Titan's crescent nearly encircles its disk due to small haze particles high in its atmosphere scattering the incoming light of the distant Sun.

Image: NASA/JPL-Caltech/Space Science Institute.