Io is a volcanic powerhouse, defying all expectations. Violent eruptions shoot out columns of gas and dust that reach far out into space, and send rivers of lava pouring across the landscape, creating a surface dotted with lakes of lava.

This little, tiny, small world of Io, you’d expect it to be geologically inactive. Instead, it’s the most volcanically active body in our solar system. The eruptions continue day in, day out, across the entire surface, a world like no other.

About the size of our moon, Io orbits closer to Jupiter than any other moon of its size. Jupiter is the largest planet in our solar system, and its gravitational pull on Io is enormous.

As Io comes in towards the planet, the gravitational pull of Jupiter is stronger, causing the very rock on Io to bulge out towards its host planet. Then, as Io moves further away, the bulge shrinks and moves, causing a tide of rock on Io that’s over 300 feet tall.

Io’s tidal bulge is continuously pulled towards Jupiter. So, as Io faces the planet at slightly different angles throughout its orbit, Jupiter not only raises the rock tide 300 feet up and down, but also drags that tidal bulge back and forth, 40 miles across Io’s surface.

As Io deforms, the intense friction generated by these tidal forces produces enough heat to drive Io’s spectacularly violent volcanism.