What lurks beneath the volcanoes of Jupiter's moon Io? NASA's Juno probe just took a peek

NASA's Juno mission has successfully captured the first measurements of the temperature beneath the surface of Jupiter's moon Io, which is recognized as the most volcanically active body in the solar system. This data was collected during two close flybys, specifically during Perijove 57 on December 30, 2023, and Perijove 58. The Microwave Radiometer (MWR) aboard the Juno spacecraft was instrumental in this endeavor, utilizing its lowest frequency microwave channels (0.6 and 1.25 gigahertz) to penetrate the surface and measure the heat rising from just beneath Io's exterior. The findings reveal significant heating within the shallow subsurface of Io, indicating that the moon's internal processes contribute to its extreme volcanic activity. The data shows that most of Io’s surface is remarkably smooth, suggesting a dynamic geological history influenced by the intense volcanic activity that characterizes the moon. The mapping of Io's hidden heat was achieved through the overlapping footprints of the MWR during the two flybys, with the northern hemisphere being primarily mapped during the first flyby. These observations enhance our understanding of Io's thermal properties and contribute to the broader knowledge of volcanic processes on celestial bodies within our solar system. The subsurface findings from Juno could transform how scientists study volcanoes across the solar system, including those on Earth.