Your Io Asplode: The Prometheus Plume

In the image middle, near the night/day shadow line, the ring shapedPrometheus plume is seen rising about 75 kilometers, or about 46 miles,
above Io while casting a shadow below the volcanic vent. Named for theGreek god who gave mortals fire, the Prometheus plume is visible inevery image ever made of the region dating back to the Voyager flybysof 1979, presenting the possibility that this plume has beencontinuously active for at least 18 years. The above digitallysharpened image was originally recorded on June 28, 1997 from adistance of about 600,000 kilometers, or 373,000 miles.

I like this picture because it almost makes Io look habitable. Aside from the continuous jettisoning of noxious gas, that is. But in several months working for ToM, I've become accustomed to it.

Io: The Prometheus Plume [NASA, via Warren Ellis]