Recently, the spacecraft has been making close flybys of the Jovian moon Io, which is the most volcanically active body in the solar system. And it has observed some dramatic features there ...

On March 8, 1979, 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.