There are not many sights more beautiful on Earth than the aurora but our planet is not the only place where they occur. In this image, scientists combined ultraviolet images of the aurora on Saturn, taken by Hubble, with visible-light images of the ringed planet from the Cassini Spacecraft.
Streams of charged particles blasted from the sun collide with Saturn’s magnetic field, creating an aurora on the planet’s south pole. Unlike Earth’s relatively short-lived auroras, Saturn’s can last for days.
While blue due to the UV light, Saturn’s northern and southern lights actually glow red on the bottom and purple on top in visible light. Earth’s auroras on the other hand are green on the bottom and red on top. The difference in color is due to variation in the dominant molecules of each planet’s atmospheres. Nitrogen and oxygen are prevalent in Earth’s auroras, while Saturn’s are composed of hydrogen.
(Image credit: NASA, ESA, J. Clarke (Boston University), and Z. Levay (STScI)