New Juno images of Io's fiery volcanoes (earthsky.org)

By Paul Scott Anderson in Space | January 6, 2019

Jupiter’s moon Io is the most volcanically active world in our solar system. The Juno spacecraft – now orbiting Jupiter – has now gazed across a distance to acquire new images and insights about the “fires of Io.”



Jupiter’s moon Io is the most volcanically active world in the solar system – even more active than Earth – with hundreds of volcanoes erupting at any almost given time. The Voyager spacecraft discovered that Io has active volcanoes, back in the late 1970s, and – in the late 1990s and early 2000s – the Galileo mission provided more stunning images of the “fires of Io.” Now, NASA’s current mission at Jupiter – the Juno orbiter spacecraft – has sent back new photos of a volcanic plume on this molten little world (image below). The news was announced by the Southwest Research Institute on December 31, 2018.

The new images and other data were taken on the winter solstice in Earth’s Northern Hemisphere – December 21 – by various instruments such as the JunoCam camera. The Stellar Reference Unit (SRU), the Jovian Infrared Auroral Mapper (JIRAM) and the Ultraviolet Imaging Spectrograph (UVS) also observed Io for over an hour, to study the moon’s polar regions as well as look for evidence of any current active eruptions.

Juno isn’t designed to study the moons of Jupiter up close, as Galileo or Voyager did. Rather, Juno’s focus is on Jupiter itself. But Juno can and now has still made important observations from a distance. The observations of Io paid off, according to Scott Bolton, principal investigator of the Juno mission and an associate vice president of Southwest Research Institute’s Space Science and Engineering Division: