Taken during an eclipse of IO, the aurorae of Io can be seen.
With all of the volcanic activity on Io, there is a constantly replenished cloud of material available for the making of spectacular atmospheric and surrounding space phenomena.
Different colors represent emission from different components of the atmosphere (green comes from emitting sodium, red from emitting oxygen, and blue from emitting volcanic gases like sulfur dioxide).
By NASA/JPL/University of Arizona - Adapted from http://photojournal.jpl.nasa.gov/catalog/PIA01637, Public Domain, Link
