Earth has only one natural satellite, the moon, which is relatively large compared to its parent planet. It orbits Earth at ...

as its Galilean moons show off while they dance in their orbits around the gas giant. Tonight, Europa and Ganymede transit Jupiter together, as they have a few other times this month. However ...

NASA scientists have sought to understand planet Jupiter, the gas giant whose mass is more than the rest of the planets in ...

On the fiery Io, the innermost and third-largest of Jupiter’s four Galilean moons ... host planet, the moon is subjected to a tremendous gravitational pull as it orbits Jupiter once about ...