NASA”s Juno spacecraft now orbiting Jupiter has spotted what may be a previously undiscovered volcano on the small moon Io, the most geologically active body in the solar system. The data were collected by Juno’s Jovian InfraRed Auroral Mapper, or JIRAM, instrument on 16 December 2017 when the spacecraft was at a distance of 470,000 kilometres (290,000 miles).
“The new Io hotspot JIRAM picked up is about 200 miles (300 kilometres) from the nearest previously mapped hotspot,” said Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome. “We are not ruling out movement or modification of a previously discovered hot spot, but it is difficult to imagine one could travel such a distance and still be considered the same feature.”
According to NASA, Io’s surface “is covered by sulphur in different colourful forms. As Io travels in its slightly elliptical orbit, Jupiter’s immense gravity causes ‘tides’ in the solid surface that rise 300 feet (100 meters) high on Io, generating enough heat for volcanic activity and to drive off any water. Io’s volcanoes are driven by hot silicate magma.”
Juno’s instruments will continue to monitor the moon during even closer flybys planned later in its mission. During previous missions by NASA’s Voyager probes, the Galileo orbiter, the Saturn-bound Cassini and and the New Horizons probe that flew past Pluto, some 150 active volcanoes were discovered with another 250 hot spots representing apparent volcanism.