Io is the most volcanically active body in our solar system, as a result of gravitational squeezing from the planet. NASA image of Io, Jupiter's third-largest moon.

Unlike Earth, whose spinning iron core generates a planet-wide magnetic field, Io has no magnetic field of its own. Instead, it is shrouded beneath Jupiter's massive magnetosphere.

From Jupiter's Moon, Io, Come Ideas About What Earth May Have Looked Like As A Newborn Planet. ScienceDaily . Retrieved June 3, 2025 from www.sciencedaily.com / releases / 2004 / 03 / 040322080941.htm ...

During its most recent close flyby of the planet, its 55th, Juno passed just 7,270 miles (11,700 kilometers) from Io, making it the closest pass since NASA’s Galileo probe imaged the volcanic ...