Jupiter's moon Io is the solar system's most volcanic body thanks to a gravitational tug of war that rages below its surface. But now scientists know the violent moon has always been this way.

Jupiter's violent moon Io has been the solar system's most volcanic body for around 4.5 billion years

Source: space
Source Link: https://www.space.com/jupiter-moon-io-most-volcanic-body-solar-system-4-5-billion-years