ABSTRACT
As we have seen, in ordinary flat spacetime the graviton is best described as a massless field of spin-2, but its interaction with matter is not consistent. A closer inspection shows that this inconsistency stems from the fact that the graviton itself has an energy–momentum, which has to be included in a complete theory. The related correction leads to nonlinear effects: the energy-momentum of matter is a source of the gravitational field, the energy–momentum of which becomes a source of the new field, etc. Can this nonlinear correction account for the small discrepancy in the precession of the perihelion of Mercury? Surprisingly enough, the answer is yes. Moreover, the 'simplest' solution to the nonlinear self-coupling problem leads to a theory which is identical to Einstein's GR. This result gives an unexpected geometric interpretation to the field-theoretic approach.
