Probably the Voyager image that stunned scientists the most was that of an active volcano on Jupiter's moon Io. The Pioneer probes had detected volcanoes on Io but none were believe to be alive.
Voyager's past and future at the edge of the solar system (photos)
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![Riding a tsunami in a protective pod [gallery]](http://i4.spstatic.com/gallery/6387315-165-100.jpg)
