Our Universe has probably a space-time with a humpy metric. The space-time has nondegenerate (unequal) geodesics. The Universe is weakly inhomogeneous. The nonstationary inhomogeneities (humpies) of gravitational field change the redshift of any astronomical object - change brightness (Sachs-Wolfe’s effect), and change trajectories of photons. The latter effect is considered here. It is found that a theorem on the null geodesics are instable in the Universe with positive density contrasts. Photons must lose an information of their initial directions of propagation. So such radiation as the Microwave Background Radiation must seem uniform in the Universe.