Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. The Juno mission ...

Roughly 40 years ago, the Voyager 1 spacecraft sailed past one of Jupiter’s large moons, and it revealed something amazing: The rocky moon, called Io, is a volcanic champion, featuring the first ...

Io is the most volcanic body known to science, and researchers have puzzled over its history for years. A new report suggests it was born this way. This image revealing the north polar region of the ...

Scientists can say two things with certainty about Io. First, this moon of Jupiter is the most volcanic object in the known universe. Its surface is festooned with so many lava-spewing calderas that ...

Why it's so special: NASA's Juno spacecraft has captured the closest views of Io since NASA's Galileo spacecraft imaged the volcanic world in 2001. Passing within just 930 miles (1,500 kilometers) of ...

Explore Io, the most volcanically active body in the solar system. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Io — Jupiter's fifth moon — is ...