Io — Jupiter's fifth moon — is the most volcanically active body in the solar system. Io's surface is peppered with hundreds of volcanoes, some spewing sulfurous plumes hundreds of miles high.

Because Io is so close to its massive host planet, the moon is subjected to a tremendous gravitational pull as it orbits Jupiter once about every 42 hours, according to the Planetary Society.

Jupiter's moon Io is the solar system's most volcanic body thanks to a gravitational tug of war that rages below its surface. But now scientists know the violent moon has always been this way.

Jupiter's volcanic moon Io doesn't appear to have a subsurface ocean of magma, resolving some issues about how Io's volcanoes erupt and raising broader questions about similar magma oceans within ...

A NASA spacecraft made its closest-ever approach to Jupiter's moon Io, coming within 930 miles of the "surface of the most volcanic world," and the space agency released new images of the flyby ...

Jupiter moon of Io is famed for its volcanoes. NASA just spotted the most powerful one yet Not only was the hot spot larger than Earth’s Lake Superior, but it also was seen belching out ...

Jupiter's moon Io is a volcanic hellscape—and has been since the solar system began Io is the most volcanic body known to science, and researchers have puzzled over its history for years. A new ...

Recent flybys of the fiery world refute a leading theory of its inner structure—and reveal how little is understood about geologically active moons.

The spacecraft came to within 930 miles of Io's surface—the closest any spacecraft has flown by the Jovian moon in over 20 years.

Io is most volcanically active. This animation is an artist’s concept of Loki Patera, a lava lake on Jupiter’s moon Io, made using data from the JunoCam imager aboard NASA’s Juno spacecraft.

Flybys of Jupiter’s moon Io, the only known volcanic world in our solar system, have captured images of a massive lava lake and a towering Matterhorn-like mountain.

Jupiter's moon Io, the most volcanic world in the solar system, was imaged from just 7,260 miles away.