Image: NASA/JPL/University of Arizona/University of Leicester
Earth is not the only planet with the phenomenon of polar lights, Saturn has 'em too! NASA's Cassini orbiter captured infrared images that revealed the stunning sights. From National Geographic's Breaking Orbit Blog:
In the picture, the ring of green auroras might seem faint, but that curtain of light is shooting up about 600 miles (1,000 kilometers) from the cloud tops of Saturn's south polar region.
In general, astronomers think auroras on Saturn occur via a process similar to the one that creates Earth's polar lights.
Charged particles from the sun flow along the planet's magnetic field lines, hitting the upper atmosphere at the poles. There the particles excite (or transfer energy to) atoms in the atmosphere, and the excited atoms release the excess energy as light.
In Saturn's case, auroras can also be sparked by electromagnetic waves generated when the planet's moons move through the charged gas that fills Saturn's magnetosphere, the bubble around the planet created by its magnetic field.