Far out in the Saturn system, a small world refuses to behave. Iapetus spins in a way that should not be so stable, wears a ...

Saturn’s largest moon has long looked like a frozen time capsule of early Earth, but a new set of measurements has upended ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't ...

A growing fleet of privately built spacecraft is preparing to attempt robotic landings on the moon as humanity's exploration ...