Mars has two moons, Phobos and Deimos. Scientists still debate whether these came from asteroids that passed close into Mars' ...

Four tiny specks of light close by the giant planet are the biggest of the Jupiter’s 95 moons. If we weren’t dazzled by Jupiter’s own glare, these moons are bright enough to be seen by the ...

Known for its Great Red Spot, Jupiter also boasts four bright, fast-moving moons: giant Ganymede, cratered Callisto, volcanic Io, and icy Europa. And there’s no better time to brave the cold and ...

ESA's Mars Express orbiter captured footage of the Mars' moon Deimos pass in front of Ganymede, Europa, Jupiter, Io and Callisto (in that order). Credit: Space.com | footage credit: ESA/DLR/FU Berlin ...

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 ...

In 1979, NASA Jet Propulsion Laboratory (JPL) scientist Linda Morabito discovered volcanic activity on Jupiter’s innermost moon, Io. But Io isn’t just volcanically active—it is the most ...

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