For a long time, I have wondered if space has a preferred reference frame. As one looks at the cosmic microwave background radiation, ask your self what would it look like if I accelerated myself in one direction. You would expect a bluer shift in one direction and redder shift in the other. Because of the difference in temperature of the cosmic background radiation, there would arise a difference in the radiation pressure, a sort of brake on movements with respect to the preferred reference frame. If a braking effect exists, how large would the effect be? further more if it did exist, it should be quite small, but the cumulative effect over billions of years may make it pronounced, and so, should be factored into cosmic theories. On the scale of a galaxy or clusters of galaxies over billions of years, does it have the potential to do away with the need for dark matter theories? Also, when the universe was fairly young and much hotter (after photon decoupling), could it have been stronger and helped contribute to the early formation of galaxies?