New findings from NASA’s Juno mission have negated the possibility of a magma ocean beneath Io, Jupiter’s volcanic moon, changing previous scientific assumptions.
Recent data from NASA’s Juno probe have caused a shift in understanding the volcanic eruptions on Io, Jupiter’s moon. Initially, it was believed that a vast magma ocean existed beneath Io’s surface, fueling its numerous volcanoes. This notion stemmed from the Galileo mission’s magnetic induction measurements in the 1990s, which suggested a 31-mile-deep layer of molten rock. However, the recent measurements from Juno, paired with historical data, have dismissed this idea, indicating a more solid interior.
Io, known for its volcanic activity, has approximately 400 active volcanoes. The moon is engulfed in lava plains, and the molten rock that surfaces as lava originates from ‘melt’ areas within its mantle. These magma pockets are remnants of underground processes. The energy causing this molten state originates from tidal heating, a result of Io’s gravitational interactions with Jupiter and its neighboring moons Europa, Ganymede, and Callisto.
Juno’s lengthy mission to Jupiter, which commenced in 2016 and included over 60 orbits, enabled close fly-bys of the Galilean moons. During late 2023 and early 2024, Juno approached within 930 miles of Io. Such proximity allowed researchers, led by Ryan Park from NASA’s Jet Propulsion Laboratory, to analyze Io’s gravitational field changes. The findings, observed through Doppler measurements, suggested Io was notably rigid, countering the existence of a global magma ocean.
The rigid nature of Io’s structure contradicts the previously held belief about its volcanic underbelly. In contrast to Earth, where tectonic forces play a role in generating surface ‘melt,’ Io’s volcanic activity is not the result of a coherent magma ocean but rather isolated pockets of magma that find their way to the surface. This conclusion holds significance not just for understanding Io, but potentially for other celestial bodies too.
The implications of these findings extend to the study of exoplanets, particularly those orbiting close to small stars, known as M-dwarfs. Similar to the Io-Jupiter gravitational dynamic, these exoplanets might experience tidal forces. The absence of a magma ocean on Io raises questions about the likelihood of similar oceans existing on these exoplanets.
NASA’s Juno mission has successfully challenged old beliefs about Io’s magma dynamics, suggesting that instead of a magma ocean, smaller magma pockets fuel its volcanic eruptions. These results, published in Nature, hold potential implications for understanding tidal heating effects on other planetary bodies.
Source: Space
