Io - Moon of Jupiter, the most volcanic active planet

Moon of Jupiter With hundreds of volcanoes, some spouting lava fountains dozens of miles (or kilometers) high, Io is the most volcanically active planet in the Solar System. Io is caught in a tug-of-war between Jupiter's huge gravity and the lesser but perfectly timed gravitational pulls of two nearby moons, Europa and Ganymede, which orbits farther from Jupiter. Io is a mortal lady who was turned into a cow in Greek mythology amid a dispute between the Greek god Zeus (Jupiter in Roman mythology) and his wife, Hera (Juno to the Romans). Size and Distance Io, Jupiter's third largest moon and the fifth in distance from the planet is somewhat larger than Earth's Moon. Orbit and Rotation The massive moons Europa and Ganymede cause Io's orbit to become unusually elliptical, despite the fact that it always points the same side toward Jupiter in its orbit around the giant planet. As a result, Io is subjected to immense tidal forces at various distances from Jupiter. ...