Initially believing they were distant stars, Galileo’s repeated observations over several nights and realized they were moons orbiting the gas giant. And thus, Io, Europa and Ganymede became ...

You’re looking at its four Galilean Moons, by far the largest of the giant planet’s estimated 79 moons. Their collective name comes from the fact that Galileo first observed them in the year 1609.

Saturn, Jupiter’s outer neighbour, currently has 83 known satellites. The four larger moons mentioned above, also known as the 'Galilean moons', account for 99.997 percent of the total mass of Jupiter ...

Saturn's moons are much smaller than Jupiter's four large moons: Ganymede (the largest satellite in the Solar System), Callisto, Io and Europa, known collectively as the 'Galilean' moons after the ...