My dear Brothers, have you ever thought about how many moons are there in our solar system?Nearly, 200+But the main point is: do you know which is the biggest? (List of 10 biggest moons)Ganymede moon if Jupiter. You can understand this simply by this example.If Ganymede starts orbiting then it would be a planet but it is bigger than mercury and has very little difference from mars. This is one of the 10 facts about different moons. You can others also: Here.