Saturn’s Aurora

This is the first image of Saturn¿s ultraviolet aurora taken by the Space
Telescope Imaging Spectrograph on board the Hubble Space Telescope in
October 1997, when Saturn was at a distance of 1.3 billion kilometers (810
million miles) from Earth. Saturn¿s auroral displays are caused by an
energetic wind from the Sun that sweeps over the planet, much like the
Earth¿s aurora that is occasionally seen in the nighttime sky, and is
similar to the phenomenon that causes fluorescent lamps to glow. But
unlike Earth¿s aurora, Saturn¿s is seen only in ultraviolet light
invisible from the Earth¿s surface, hence the aurora can be observed only
from space. New Hubble images reveal variations and regularities
indicating that the aurora is primarily shaped and powered by a continual
tug-of-war between Saturn¿s magnetic field and the flow of charged
particles from the Sun.

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