Galileo Galilei observes a few in the four largest moons of Jupiter for The very first time. He named them, and in turn the four are known as the Galilean moons. Ganymede not identified by him until January 13.쥬니어네이버는 아동들을 위한 포털 사이트이다. 쥬니어 네이버는 아바타, 교육 콘텐츠, 퀴즈, 동영상, 질