What is the difference between a planet and a moon?

There is a very basic difference between the two: A planet revolves around the Sun and a moon orbits a planet. Technically, the moon also orbits the Sun as it spins around its planet, but because it has its own sub-orbit of a planet scientists define it as a moon. All planets in our solar system, except for Mercury and Venus, have moons. Earth has one moon, Mars has two, Neptune has thirteen, Uranus has twenty-seven, Jupiter has sixty-six, and Saturn has sixty-two. Pluto, now classified as a dwarf planet, has five moons.


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