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Gravity is needed for an object to stay in orbit. An orbit is a repeating path that a mass in space takes around another mass, like the Moon goes around Earth. Newton’s First Law of Motion says that an object in motion will stay in motion unless something pushes or pulls on it. Without gravity, the Moon would go off into space along a straight line. With gravity, it is pulled back toward Earth. An orbit is a balance between an objects tendency to move in a straight line and the pull of gravity from the object being orbited.