NASA's Voyager 1 spacecraft discovered active volcanoes on Jupiter's moon Io. Before Voyager 1 flew by Io, scientists believed the moon to be a dead world much like Earth's moon. The mission ...

Voyager 2 preceded ... (Io, left, and Europa) on Feb. 13, 1979. Io is about 220,000 miles above Jupiter's Great Red Spot; Europa is about 375,000 miles above Jupiter's clouds. This color image ...

Coming eerily close to the moon, the small spacecraft was able to capture images of twin volcanic plumes on Io’s surface, sending material erupting into space. This new flyby was only the second ...