A moon is a natural satellite that orbits around a larger object like a planet. A natural satellite is different from a human made satellite because natural satellites are produced naturally. Moons usually have a stable orbit. This means that the rate of which the moon circles around the planet is just the right speed. If the orbit is too fast or too slow, it is an unstable orbit. Moons are formed in to different ways. One way is that the moon could be an asteroid that has been pulled into a planet’s orbit. An asteroid is a large piece of rock and metal that is just floating into space. These asteroids can be protoplanets, or planets that have not yet become big enough to be considered planets. The asteroid could be drawn closer and closer to a planet because of it’s strong gravitational pull. That makes the asteroid orbit the planet. That is one way a moon can come about. Another way a moon can form is when an asteroid or protoplanet collides or crashes into an existing or forming planet. This causes a giant piece of rock or dust to come off of the existing planet and start to orbit around it. This is how moons are formed!