Callisto's surface is the Solar System's most heavily cratered. Voyager 2 took a dramatic photo of this cratered world in 1979.

Callisto, Jupiter's second-largest moon, may have a rocky surface with an ocean beneath the surface. If there was a contest for the most interesting moon in our solar system, Callisto would be a ...

Often overshadowed by Europa and Ganymede, Callisto is actually one of the largest moons in our solar system. In this video, ...

Scientists using old flyby data from NASA's Galileo mission have found stronger evidence that Jupiter's moon Callisto has an ocean.

Jupiter's moons resemble little moons! Do they orbit in a regular pattern, similar to how the Moon orbits the Earth? Today, ...

"JUICE will use the gravity of Venus this week to bend its orbit around the sun and gain speed relative to Earth without using fuel," ESA wrote in the Aug. 25 statement. "JUICE will use the Earth ...

Mercury, Venus, and Jupiter all congregate in the morning sky, joined by the Waning Moon and the bright stars of Gemini this ...

Jupiter's four Galilean moons will line up in front of Jupiter in the early morning sky on Aug. 8. The predawn hours of Aug. 8 present a perfect opportunity to see Jupiter's four largest moons line up ...

Europe's JUICE Jupiter probe lost contact with Earth for nearly a full day recently, but the problem was solved in time for ...

We already know a decent amount about how planets form, but moon formation is another process entirely, and one we're not as ...

If there was a contest for the most interesting moon in our solar system, Callisto would be a contender. Jupiter's second-largest moon has more impact craters on its surface than any other ...