DFT can be used with Kohn-Sham to study the many-body system of the gravitationally interacting planets and the sun as follows: Let us consider that the planets are quasi-particles that interact with each other, the kinetic energy of these quasi-particles is calculated by the sum of each of these for their corresponding planets, then we can add taking the sun as a nucleus subject to coulomb of nuclei, we also add the interaction with the statistical interaction of the rest of all the other planets, finally we add the exchange potential- evaluation that will be calculated from a functional and that will be associated with the density