Gravitational effects in the propagation and in the emission of light

Following Chou's viewpoint that the Cartesian system of space coordinates a nd time defines a Minkowskian space-time in which Einstein's field equation s and the harmonic condition are the laws of gravitation (Ref. [1]), we stu dy the effects of an external gravitational field in the propagation and in the emission of light respectively from the generalized Maxwell and Dirac equations of the general theory of relativity by geometric optics and quant um mechanics, and get the usual results for the red shift. For the naively homogeneous and isotropic model of cosmology (the case with k = 0 in the Ro bertson-Walker scheme) closed form for the relation between distance and re d shift is obtained, which indicates that a nerv way of analyzing the obser vational data with not too small red shifts is needed.