About our Io news
Latest news on Io, the innermost and the largest of Jupiter's four Galilean moons. With a diameter of 3,642 kilometres, it is slightly larger than Earth's Moon. Io is the fifth-largest moon in the Solar System, and has the highest density of all the moons of Jupiter. It has a thin atmosphere composed of sulphur dioxide and sulphur.
Io is the most geologically active body in the Solar System. It is covered with volcanoes that erupt sulphur, sulphur dioxide and silicate rocks. Io's surface is also dotted with hundreds of mountains.
Io has a very eccentric orbit, which means that it experiences extreme tidal forces from Jupiter. These tidal forces cause Io to heat up, and as a result its interior is partially molten. This makes Io the most volcanically active body in the Solar System.