
The most volcanically active world in the solar system, Jupiter's moon Io, may possess a global ocean of magma underneath its surface, as well as mysteriously warm poles, a new study finds.
Io, the innermost of Jupiter's four largest moons, is slightly bigger than Earth's moon. Io is the most volcanically active body in the solar system, bursting with plumes that rise up to more than 300 miles (500 kilometers) above the surface.