
                    
                      2 ---->    i=N
                     d   OC     -----       M
                           k    \            i     ----->
                    --------- = /     G ----------- C C
                         2      -----            3   k i
                       dt        i=1     |----->|
                                (i#k)    | C C  |
                                            k i
This allows us to display the motion of the 9 planets.