NASA's Juno spacecraft, after over 40 years of scientific curiosity about Jupiter's moon Io, has revealed that the gigantic volcanic activity on its surface does not depend on a global ocean of molten magma, as previously thought. Instead, Juno's close flybys in 2023 and 2024 provided accurate data showing that each volcano is fed by separate magma chambers. This discovery shifts the long-standing understanding of Io, which is known as the most volcanically active body in the solar system, featuring over 400 active volcanoes.

Io has puzzled scientists since the Voyager spacecraft captured its first images revealing volcanic plumes back in 1979. The question of what ignites these cosmic flames has remained unanswered for more than four decades. The new study, published in the journal Nature, relied on precise measurements of Io's gravitational field. By tracking slight changes in Juno's path during its close passes to the moon, scientists could better elucidate Io's internal structure, leading to crucial insights into its volcanic processes.

The implications of Juno's findings are significant for our understanding of planetary geology and the dynamics of celestial bodies. If Io were to have a global magma ocean beneath its surface, it would have shown a larger tidal deformation indicative of such an environment. This new information not only enlightens Io's unique geological characteristics but also raises questions about volcanic activity on other celestial bodies, enhancing our knowledge of the complexities of the solar system.