Supposing we have two objects of masses m1 and m2 repeated by a large distance and sufficiently distant from any other masses or gravitational fields. The masses are not moving relative to each other initially. The masses will eventually move together by their mutual gravitational attraction to form another mass which we will call m3. What will be the mass of m3? The reader may initially reply m1+m2. However there is a problem here. The masses will have kinetic energy when they collide which will be released as heat or radiation. Where does this energy come from? According to the laws of conservation of mass / energy and mass / energy equivalence, will the resultant mass m3 be less than m1+m2? Will the energy released come from the resultant mass according to e=mc^2 or e=m (if we put c=1)?