The Aurorae on Saturn

This is the first image ever taken of bright aurorae at Saturn's northern and southern poles, as seen in far ultraviolet light by the Wide Field and Planetary Camera 2aboard the Hubble Space Telescope.

The aurora is produced as trapped charged particles precipitating from the magnetosphere collide with atmospheric gases -- molecular and atomic hydrogen in Saturn's case. As a result of the bombardment, Saturn's gases glow at far-ultraviolet wavelengths (110-160 nanometers) which are absorbed by the Earth's atmosphere, and so can only be observed from space-based telescopes.