Screening the graviton background, graviton pairing, and Newtonian   gravity
  It is shown that screening the background of super-strong interacting gravitons creates for any pair of bodies as an attraction force as well an repulsion force due to pressure of gravitons. For single gravitons, these forces are approximately balanced, but each of them is much bigger than a force of Newtonian attraction. If single gravitons are pairing, a body attraction force due to pressure of such graviton pairs is twice exceeding a corresponding repulsion force under the condition that graviton pairs are destructed by collisions with a body. If the considered quantum mechanism of classical gravity is realized in the nature, then an existence of black holes contradicts to Einstein's equivalence principle. In such the model, Newton's constant is proportional to $H^{2}/T^{4},$ where $H$ is the Hubble constant, $T$ is an equivalent temperature of the graviton background. The estimate of the Hubble constant is obtained $H=2.14 \cdot 10^{-18} s^{-1}$ (or $66.875 km \cdot s^{-1} \cdot Mpc^{-1}$). 
Michael A. Ivanov