We finally have a better understanding of Jupiter's volcanic moon, Io. On its scheduled flyby, the New Horizons spacecraft used its Alice ultraviolet spectrograph to photograph the aurora on Io for the first.
New Horizon's spectrograph readings showing the aurora on Io have given researchers the necessary information to calculate how much both the frozen surface material and volcanic plumes contribute to the atmosphere.
Io is the most volcanic object in the solar system. Io hurls sulfur-dioxide hundreds of the miles into the air where it eventually freezes. The frozen gas remains largely on the surface, slowly emitting gas that makes up approximately 97% of Io's atmosphere. During the daytime, present volcanic activity accounts for the remaining 3% of the atmosphere.
Io's aurora performs in much the same way Earth's does. Io's magnetosphere blocks the incoming radiation from the solar wind and the charged particles create the aurora, the visual phenomenon known as the "Northern Lights (aurora borealis)" or "Southern Lights (aurora australis)" on Earth.