Researchers observing Jupiter's moon Io detected five simultaneous volcanic eruptions at the end of 2024, releasing vast amounts of lava and hinting at an interconnected magma network beneath the surface. The event, captured by NASA's Juno spacecraft, spanned 65,000 square kilometers and exceeded previous eruptions in energy. This discovery challenges existing models of Io's interior and offers insights into early Earth's volcanic activity.
At the close of 2024, NASA's Juno spacecraft provided a stunning view of Jupiter's moon Io, where five volcanoes erupted in unison near the south pole. The synchronized activity unleashed a massive lava flow covering approximately 65,000 square kilometers, surpassing the energy of any prior eruption observed on the moon. Jani Radebaugh, a researcher at Brigham Young University in Utah, described the scene: “There was this one gigantic eruption and lava flow, and that’s what first caught our eye, but on second look, all these other hotspots lit up as well.” She added, “There’s so much magma that we can’t quite wrap our minds around it.”
Radebaugh painted a vivid picture of the event's scale: “Picture standing at the edge of one of these features, and the valley that has been cold suddenly fills up with an entire lake of lava. As it fills up, you turn and look over your shoulder, and another massive crack opens up in the ground and fills with lava at exactly the same time.” This simultaneous outburst raises questions about Io's subsurface structure. Earlier studies ruled out a global magma ocean beneath the crust, leaving the source of such voluminous eruptions unclear.
To explain the phenomenon, Radebaugh and her team propose a 'magma sponge'—an interconnected network of pores filled with magma that erupts through surface hotspots. Confirmation will require further observations, though Juno's increasing distance from Io may delay such data. Despite its size, comparable to Earth's moon, Io's intense volcanism mirrors the hotter, more active conditions of early Earth. As Radebaugh noted, “This is actually like early Earth when it was much hotter and more active, so Io can tell us a lot about our past.” The findings appear in the Journal of Geophysical Research: Planets (DOI: 10.1029/2025JE009047).