A simple breakdown of the new 3I/ATLAS pulsing discovery and why scientists are checking if Callisto might be affected.

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 ...

New evidence from an old NASA mission supports the theory that Jupiter's moon Callisto is in fact an ocean world. Credit: NASA / JPL / DLR A moon of Jupiter about the size of Mercury likely has a ...

More pocked with craters than any other object in our solar system, Jupiter's outermost and second-biggest Galilean moon, Callisto, appears geologically unremarkable. In the 1990s, however, NASA's ...

The interstellar comet 3I/ATLAS has started to brighten and dim in a remarkably steady rhythm, repeating every 16.16 hours as ...

NASA reveals the true, bizarre reason for the 3I/ATLAS comet's 16.16-hour pulse. Scientists link the interstellar object's rhythmic jets to Jupiter's moon Callisto.

Jupiter, the giant of our Solar System, hosts nearly 100 moons. Discover some of Jupiter moons with unique characteristics to explore.

The predawn hours of Aug. 8 present a perfect opportunity to see Jupiter's four largest moons line up next to the "King of the Planets" as it voyages through the stars of the constellation Gemini.

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 planetary ...