Galileo first discovered the four largest moons of Jupiter, Io, Europa, Ganymede, and Callisto in 1610, using a 20-power telescope;
(Galileo; discovered; the four largest moons of Jupiter, Io, Europa, Ganymede, and Callisto; T:in 1610; T:first)
Galileo
discovered
the four largest moons of Jupiter, Io, Europa, Ganymede, and Callisto T:in 1610 T:first