If I have 2 electricly charged bodies orbiting one another, the binding energy must contribute to the gravitation of the system. Their reletive KE must also. So the total gravitational mass of the system is greater then the sum of the indivual objects. If I used a laser and gravitational lensing to map mass distribution of the system where would I find the extra mass? Next question: Does gravitational binding energy work the same way? How large is the gravitational binding enery and the internal kinetic inergy of a galaxy in comparison to the missing mass-energy of dark matter?