Exploration & discovery

Voyager 1 reveals Jupiter and its volcanic moon Io

5 March 1979

Voyager 1 made its closest approach to Jupiter on 5 March 1979, photographing the Great Red Spot, the planet's swirling bands and its faint ring. Its images of the moon Io, taken days later, showed active volcanoes erupting plumes hundreds of kilometres high, the first volcanic activity seen on another world. Voyager 2 followed in July and revealed signs of a global ocean beneath the icy crust of Europa. The flybys turned the Galilean moons from points of light into worlds.

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