First Active Volcanoes Beyond Earth
Date: 8 Mar 1979
This dramatic view of Jupiter's satellite Io shows two simultaneously occurring volcanic eruptions.
One can be seen on the limb, (upper left) in which ash clouds are rising more than 260 km (150 miles) above the satellite's surface. The second can be seen on the terminator (shadow between day and night) where the volcanic cloud is catching the rays of the rising sun.
This photo was taken by Voyager 1 looking back 4.5 million km (2.6 million miles) at Io, three days after its historic encounter. This is the same image in which Linda A. Morabito, a Jet Propulsion Laboratory engineer, discovered the first extraterrestrial volcanic eruption (the bright curved volcanic cloud on the limb).