The Cassini spacecraft has captured this psychedelic false colour view of Saturn's aurora (in green). If we think that Earth's aurora is awesome, imagine being there watching an aurora larger than a dozen Earths. Here's the time-lapse video:
The Saturnian aurora's brightness changes during the planet's 10-hour, 47-minute day, a phenomenon that may be connected to the angle of the sun. Some of its features rotate with the planet, appearing at the same time and place every day, which indicates that this may be linked to Saturn's magnetic field.
Other features can be seen to rotate with the planet, reappearing at the same time and the same place on the second day, suggesting that these are directly controlled by Saturn's magnetic field. Or the Evil Emperor Ming. [NASA]