Jupiter's fifth moon, Io, is the most volcanically active body in the solar system. read more
Jupiter’s fifth moon, Io, is the most volcanically active body in the solar system. Plumes of sulfur spew upward as high as 190 miles (300 kilometers). The surface of Io is splotched with lava lakes and floodplains of liquid rock. Io by the numbers. Age: Io is about 4.5 billion years old, about the same age as Jupiter. read more