The perihelion of Mercury advance and the light bending calculated in (enhanced) Newton's theory

We show that results of a simple dynamical gedanken experiment interpreted according to standard Newton's gravitational theory, may reveal that three-dimensional space is curved. The experiment may be used to reconstruct the curved geometry of space, i.e. its non-Euclidean metric (3)gik. The perihelion of Mercury advance and the light bending calculated from the Poisson equation (3)g(ik)del(i)del(k)Phi = -4 pi G rho and the equation of motion F-i = ma(i) in the curved geometry (3)gik have the correct (observed) values. Independently, we also show that Newtonian gravity theory may be enhanced to incorporate the curvature of three dimensional space by adding an extra equation which links the Ricci scalar R-3 with the density of matter rho. Like in Einstein's general relativity, matter is the source of curvature. In the spherically symmetric (vacuum) case, the metric of space (3)gik that follows from this extra equation agrees, to the expected accuracy, with the metric measured by the Newtonian gedanken experiment mentioned above.