(Left) Io as seen by NASA's Galileo spacecraft on 3 July 1999 (Right) A massive volcanic hotspot observed by Juno in 2024. The most violent volcanic cataclysm ever seen in our solar system has been witnessed on Jupiter’s moon Io by NASA’s Juno spacecraft, with simultaneous eruptions covering an enormous 40,400 square miles (65,000 square kilometers). The synchronous eruptions point to a hitherto undetected network of interconnected magma reservoirs just beneath the volcanic moon’s lava-encrusted surface. Images of Io taken by Juno during several fly-bys detect how the region in which the volcanic event was located changed. During future fly-bys of Io, Juno will survey the moon’s surface looking for new lava flows and ash deposits resulting from this spectacular volcanic eruption.