What are the four largest moons of Jupiter called?

One of the first telescopic discoveries, these four moons of Jupiter—from innermost to outermost—were found by Galileo Galilei in 1610 through telescopic observation. They are called Io, Europa, Ganymede, and Callisto.

When it comes to the potential for extraterrestrial life, the Galilean moons may be more intriguing than Jupiter itself.

Strong Jovian tides force constant volcanic activity on Io, driving out water and most other volatile compounds and probably ending life as we know it. Similarly, planets that orbit nearby low-luminosity stars but are otherwise potentially Earth-like might experience the same fate.

The other three Galilean moons, on the other hand, have all likely retained substantial amounts of water ice and, like Europa, may even have subterranean watery oceans that support life.

The four largest moons of Jupiter are called Io, Europa, Ganymede, and Callisto.