<P> The Galilean moons are the four largest moons of Jupiter -- Io , Europa , Ganymede , and Callisto . They were first seen by Galileo Galilei in January 1610 , and recognized by him as satellites of Jupiter in March 1610 . They are the first objects found to orbit another planet . Their names derive from the lovers of Zeus . They are among the largest objects in the Solar System with the exception of the Sun and the eight planets , with a radius larger than any of the dwarf planets . Ganymede is the largest moon in the Solar System , and is even bigger than the planet Mercury . The three inner moons -- Io , Europa , and Ganymede -- are in a 4 : 2 : 1 orbital resonance with each other . Because of their much smaller size , and therefore weaker self - gravitation , all of Jupiter 's remaining moons have irregular forms rather than a spherical shape . </P>
<P> The Galilean moons are the four largest moons of Jupiter -- Io , Europa , Ganymede , and Callisto . They were first seen by Galileo Galilei in January 1610 , and recognized by him as satellites of Jupiter in March 1610 . They are the first objects found to orbit another planet . Their names derive from the lovers of Zeus . They are among the largest objects in the Solar System with the exception of the Sun and the eight planets , with a radius larger than any of the dwarf planets . Ganymede is the largest moon in the Solar System , and is even bigger than the planet Mercury . The three inner moons -- Io , Europa , and Ganymede -- are in a 4 : 2 : 1 orbital resonance with each other . Because of their much smaller size , and therefore weaker self - gravitation , all of Jupiter 's remaining moons have irregular forms rather than a spherical shape . </P>
who discovered the four largest moons of jupiter
who discovered the four largest moons of jupiter
Galileo Galilei
Galileo Galilei