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Infrared imagery from the solar-powered spacecraft heats up the discussion on the inner workings of Jupiter\u2019s hottest moon.<\/em><\/p>\n New findings from NASA\u2019s Juno probe provide a fuller picture of how widespread the lava lakes are on Jupiter\u2019s moon Io and include first-time insights into the volcanic processes at work there. These results come courtesy of Juno\u2019s Jovian Infrared Auroral Mapper (JIRAM) instrument, contributed by the Italian Space Agency, which \u201csees\u201d in infrared light. Researchers published a paper on Juno\u2019s most recent volcanic discoveries on June 20 in the journal Nature Communications Earth and Environment.<\/p>\n Io has intrigued the astronomers since 1610, when Galileo Galilei first discovered the Jovian moon, which is slightly larger than Earth\u2019s Moon. Some 369 years later, NASA\u2019s Voyager 1 spacecraft captured a volcanic eruption on the moon. Subsequent missions to Jupiter, with more Io flybys, discovered additional plumes \u2014 along with lava lakes. Scientists now believe Io, which is stretched and squeezed like an accordion by neighboring moons and massive Jupiter itself, is the most volcanically active world in the solar system. But while there are many theories on the types of volcanic eruptions across the surface of the moon, little supporting data exists.<\/p>\n In both May and October 2023, Juno flew by Io, coming within about 21,700 miles (35,000 kilometers) and 8,100 miles (13,000 kilometers), respectively. Among Juno\u2019s instruments getting a good look at the beguiling moon was JIRAM.<\/p>\n Designed to capture the infrared light (which is not visible to the human eye) emerging from deep inside Jupiter, JIRAM probes the weather layer down to 30 to 45 miles (50 to 70 kilometers) below the gas giant\u2019s cloud tops. But during Juno\u2019s extended mission, the mission team has also used the instrument to study the moons Io, Europa, Ganymede, and Callisto. The JIRAM Io imagery showed the presence of bright rings surrounding the floors of numerous hot spots.<\/p>\n \u201cThe high spatial resolution of JIRAM\u2019s infrared images, combined with the favorable position of Juno during the flybys, revealed that the whole surface of Io is covered by lava lakes contained in caldera-like features,\u201d said Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome. \u201cIn the region of Io\u2019s surface in which we have the most complete data, we estimate about 3% of it is covered by one of these molten lava lakes.\u201d (A caldera is a large depression formed when a volcano erupts and collapses.)<\/p>\n JIRAM\u2019s Io flyby data not only highlights the moon\u2019s abundant lava reserves, but also provides a glimpse of what may be going on below the surface. Infrared images of several Io lava lakes show a thin circle of lava at the border, between the central crust that covers most of the lava lake and the lake\u2019s walls. Recycling of melt is implied by the lack of lava flows on and beyond the rim of the lake, indicating that there is a balance between melt that has erupted into the lava lakes and melt that is circulated back into the subsurface system.<\/p>\n \n