Every Moon in Our Solar System That Shouldn’t Exist Explained

Every Moon in Our Solar System That Shouldn’t Exist Explained Io is the most volcanically active body in the entire solar system, and it has absolutely no business being that way. At first glance, a moon orbiting a gas giant should be cold, geologically dead, and covered in craters, but Io throws every one of those expectations into a sulfurous pit. The reason Io burns comes down to its position in a gravitational argument it can never win. Io sits in an orbital resonance with its neighbors Europa and Ganymede, meaning their gravitational pulls tug on Io in a precise, repeating rhythm as they orbit Jupiter. Jupiter itself hauls on Io with enormous force, and the combined effect is tidal flexing, a constant squeezing and stretching of the moon's interior as it orbits. On Earth, tidal forces from the Moon raise ocean tides of a meter or two.