What causes volcanic eruptions on Jupiter's moon Io? Scientists aren't so sure anymore
As many as 400 volcanoes are erupting on the surface of Jupiter's innermost moon Io, with virtually every square inch of the moon covered in lava plains. The erupting lava (molten rock that reaches the surface) comes from areas of 'melt' within the mantle, which are rising pockets of magma (molten rock that's still underground).