The generalized Newton's law of gravitation versus the general theory of   relativity
  Einstein general theory of relativity (GTR) accounted well for the precession of the perihelion of planets and binary pulsars. While the ordinary Newton law of gravitation failed, a generalized version yields similar results. We have shown here that these effects can be accounted for as due to the existence of gravitomagnetism only, and not necessarily due to the curvature of space time. Or alternatively, gravitomagnetism is equivalent to a curved space-time. The precession of the perihelion of planets and binary pulsars may be interpreted as due to the spin of the orbiting planet ($m$) about the Sun ($M$)\,. The spin ($S$) of planets is found to be related to their orbital angular momentum ($L$) by a simple formula, \emph{viz}., $S\propto \,\frac{m}{M}L$\,. 
A. I. Arbab
physics.gen-ph