Inserting this function into the integral and using the equation 1 r = m k L 2 ( 1 + A m k cos ⁡ ⁡ θ θ ) to express r in terms of θ, the precession rate of the periapsis caused by this non-Newtonian perturbation is calculated to be 6 π π k 2 T L 2 c 2 , which closely matches the observed anomalous precession of Mercury and binary pulsars. This agreement with experiment is strong evidence for general relativity.