Weight and mass are mistakenly compared or considered similar by most people. Weight is the gravitational attraction between an object and the earth (or some other body). Mass does not vary, at least not under ordinary circumstances, but weight does, depending on where the object is. For example, because the Moon is less massive than the Earth, the force of attraction between the Moon and a person on it is less than the force of attraction between the Earth and the same person on it. In other words, the person weighs less on the moon. The mass remains the same, assuming that the person has not grown fatter or thinner during the journey from one place to another. The mass of an object is the same anywhere in the universe, but the weight of the object may vary, depending upon the force of the local gravity acting upon it, and other influences, such as centrifugal force. Any object in free orbit will be in a condition of weightlessness or zero gravity.