Jupiter's Moon Io
More details below:
Size & Distance
* A bit larger than Earth's Moon, Io is the third largest of Jupiter's moons, and the fifth one in distance from the planet.
(click below for greater depth 3D image - press escape to return)
* Io is the most volcanically active world in the solar system, with hundreds of volcanoes, some erupting lava fountains dozens of miles high.
* As Jupiter rotates, it takes its magnetic field around with it, sweeping past Io and stripping off about 1 ton (1,000 kilograms) of Io's material every second.
Atmosphere / Weather
* Io's orbit, keeping it at more or less a cozy 262,000 miles from Jupiter, cuts across the planet's powerful magnetic lines of force, thus turning Io into a electric generator.
* Io can develop 400,000 volts across itself and create an electric current of 3 million amperes. This current takes the path of least resistance along Jupiter's magnetic field lines to the planet's surface, creating lightning in Jupiter's upper atmosphere.
Orbit & Rotation
* Io always points the same side toward Jupiter in its orbit around the giant planet.
* Europa and Ganymede perturb Io's orbit into an irregularly elliptical one. Thus, in its widely varying distances from Jupiter, Io is subjected to tremendous tidal forces.
* These forces cause Io's surface to bulge up and down (or in and out) by as much as 330 feet (100 meters). Compare these tides on Io's solid surface to the tides on Earth's oceans. On Earth, in the place where tides are highest, the difference between low and high tides is only 60 feet (18 meters), and this is for water, not solid ground.