Juno Explores Lava Lakes on Jupiter's Moon Io: NASA

NASA's Juno spacecraft has made groundbreaking explorations into the mysterious lava lakes of Jupiter's hottest moon, Io. Juno's Jovian Infrared Auroral Mapper (JIRAM) instrument captured these revelations, shedding new light on its volcanic activity and highlighting the broad presence of these fiery features across Io's surface.

Io, first observed by Galileo Galilei in 1610, has been an object of fascination for astronomers because it is the most volcanically active body in our solar system. NASA's Voyager 1 mission captured the first recorded volcanic eruption on this moon in 1979. This discovery initiated subsequent missions that uncovered additional volcanic plumes and molten lava lakes.

Scientists theorize that due to gravitational interactions with nearby moons and Jupiter itself—causing it to stretch and squeeze like an accordion—Io holds the title of the most volcanically active world known in our solar system. However, despite various theories regarding the types of eruptions, there is limited supporting data available.

During its close encounters with Io in May and October 2023, Juno provided unprecedented infrared imagery via JIRAM, among other instruments onboard. This advanced technology enabled scientists to observe bright rings surrounding numerous hot spots on Io’s surface, signifying extensive lava lake presence within caldera-like structures.

One or more molten lava lakes reportedly cover about three percent of the areas where researchers have complete data sets from JIRAM observations.

These detailed investigations also offered insights into what lies beneath Io’s crusty exterior. The infrared pictures showed that these lava lakes had unique structural patterns. They had a central crust surrounded by walls that could be hundreds of meters high. These walls stopped magma from overflowing, which suggests that rising magma and crustal deformation are working together in a complex way below the surface.

Alessandro Mura, a Juno co-investigator, discussed the most common type of volcanism on Io, which involves large lava lakes where magma periodically rises and falls, and noted similarities between Hawaiian volcano formations, indicating similar geological processes exist despite contrasting environments.

We expect future analysis of JIRAM data from subsequent flybys in late 2023 and early 2024 to provide a deeper understanding of these volcanic processes. Scott Bolton, principal investigator for Juno, underscored the importance of these findings by enhancing our understanding of Io’s dynamic geology.

Bolton also emphasized JIRAM's role in ongoing efforts to map and monitor volcanic activity across Io's poles, which largely remain unexplored. Juno’s recent flybys continue to yield invaluable data, with future missions scheduled for July 2024 aiming at exploring Jupiter's complex dynamics further—leveraging Juno's capabilities to uncover more about Io and its fiery landscape.

"The observations show fascinating new information on Io's volcanic processes. Jimam is turning out to be one of the most valuable tools to learn how this tortured world works," said Bolton during a press statement.

The Nature Communications Earth & Environment journal recently published these important findings.