Io has 266 active volcanic hotspots linked by a global magma ocean, finds study

Jupiter's Io stands apart from the solar system's other moons, with its numerous volcanoes and its surface dominated by lava flows. Io's surface volcanism was confirmed in 1979 when the Voyager spacecraft imaged it, but its volcanic nature isn't duplicated anywhere else in our system. Tidal heating is behind the moon's eruptive nature, driven by Jupiter's powerful gravity, and by resonance with other moons. But is there a magma ocean inside Io?