The Mysterious Inner Workings of Io, Jupiter’s Volcanic Moon

Io, Jupiter's volcanic moon, continues to baffle scientists. Once thought to harbor a global magma ocean just beneath its crust, recent data from NASA's Juno spacecraft suggests this hellish underground sea doesn't exist.

Scott Bolton, who leads the Juno mission, recalls his first glimpse of Io's volcanism in 1980: "They looked amazingly beautiful. It was like an artist drew it."

For decades, researchers believed tidal heating from Jupiter's gravitational pull created a vast reservoir of liquid rock beneath Io's surface. This theory explained the moon's uniformly distributed volcanoes and aligned with magnetic field data from earlier missions.

However, Juno's precise measurements of Io's gravitational field tell a different story. "There is no shallow ocean," Bolton states definitively.

This revelation reopens questions about how tidal heating works, not just on Io but potentially on other moons like Europa, where scientists hope to find conditions suitable for life.

As researchers grapple with these new findings, Io remains an enigma. "The more we observe it," says volcanologist Ashley Davies, "the more puzzling it becomes."