Gravitons, Dark Matter, and Classical Gravitation
  We find that the quantum of gravity, the graviton, has time-varying mass (the gomidium), and radius (the somium); both vary with the inverse of R; and its frequency is given by Hubble's parameter. Dark matter can be made of such gravitons. The number of gravitons varies with R-squared . The Machian radiated power of the Universe leads us to a "correct" energy density for the gravitons as dark matter. 
Marcelo Samuel Berman