As you wish. Well, these four unknown forces are: 1) Compressive Force, 2) Integral Force, 3) Force on a field and 4) Space-Force. Details about these forces can be seen in the links. Seems correct as application of Newtonian mechanics is enhanced. Here force still can be considered as F=dE/dx; where dE is change in energy over an infinitesimal distance dx. GR is also not complete in explaining expansion of our universe. What do you mean by absolute reference frame? Here any point can be considered for reference. Can you answer my OP question in GR? As i said earlier GR is also incomplete in this regard. Time Dilation can be explained by Compressive Force. Math is explained there. Only testing is required. For Mercury Precession some unknown force must be there. For LHC particle accelerator, what is your specific question?