A point particle, also known as a point mass, is an idealized object which has mass but no extent in space. An object which does have extent in space can be considered to consist of an infinite set of point masses. If the object neither rotates nor deforms, every point mass making up the object undergoes the same motion (or lack of motion) that every other point undergoes. Hence, laws of motion that apply to a point mass can be applied to an object that neither rotates nor deforms. In the case of objects that do rotate and deform, laws of motion that apply to a point mass can be used to characterize the motion of the center of mass of the object.