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 hellish surface of a moon of Jupiter known as Io is riddled with hundreds of lava-spewing volcanoes that make the world one of chaos and violence. The brutal conditions also make Io intriguing ...

A new study counters previous theories that Jupiter's hellish moon, Io, has an ocean of lava inside powering its volcanic surface.

Before we even saw the surface of the hellish moon, scientists speculated there may be a magma ocean raging under the rocky crust due to Io’s wild tidal heating.

Scientists say Earth's Moon went through a period when it was a lot like Io, a moon of Jupiter that's full of volcanic activity.

Io, one of the most fascinating moons in our solar system, continues to mystify scientists with its intense volcanic activity and bizarre behavior. This moon, known for its towering volcanoes, ...

Io, slightly larger than Earth's Moon, will get the most sustained look from Juno, which started long-distance observations of the volcanic moon last year.

Ancient volcanic heat may have shaped the moon from the inside out, keeping one side thinner, warmer and more geologically active than the other, a new study suggests.

Observations made of Jupiter’s moon Io during the Juno mission’s flybys helped astronomers confirm how and why Io became the most volcanic world in the solar system.

Scientists are starting to learn why this moon keeps erupting with volcanoes Hundreds of volcanoes and lava lakes on Jupiter’s moon Io are likely powered in the same way as Earth’s volcanoes.

Recent strange activity around Jupiter’s volcanic moon, Io, confused and excited scientists. By Oliver Whang Io, the third largest of Jupiter’s moons, is caught in a pressurized, explosive ...

NASA's Juno spacecraft swooped by the Jovian moon Io on its closest pass yet. This year, it will travel progressively closer to the volcanic, lava-spewing moon.