Kashlinsky, Atrio-Barandela, Kocevski, and Ebeling have just put out a preprint on the peculiar motions of galactic clusters: A measurement of large-scale peculiar velocities of clusters of galaxies: results and cosmological implications. In short, they claim that all galactic clusters appear to have a motion with respect to the cosmic microwave background (CMB). The motion of a galactic cluster slightly effects the energy of the microwave radiation that travels through it, so they use the temperature map of the CMB to determine the velocity of those galactic clusters.
And the result is that the whole (observable) universe appears to be moving with respect to the CMB. This was not expected because the observable universe is approximately isotropic and so shouldn’t be going anywhere. They write (in the abstract):
This flow is difficult to explain by gravitational evolution within the framework of the concordance LCDM model and may be indicative of the tilt exerted across the entire current horizon by far-away pre-inflationary inhomogeneities.
However, the tilt is easy to explain when you assume that the speed of gravity is larger than C: If gravitational interactions travel faster than light, you will automatically be able to feel the gravitational attraction of matter even if it is too far away for you to see.
I hadn’t put 2+2 together until Kea mentioned to me that she was getting a lot of hits on her blog that seemed to be coming from this blog. I looked at my logs and found that my post on the speed of gravity, (which discusses various theories and measurements of gravity’s speed) was getting most of the attention.
Some other posts on the subject
If gravity exceeds the speed of light, this is an example of Lorentz violation. Feynman’s checkerboard model, when extended to 3 dimensions, violates the speed of light in a manner I think similar to gravity.
The cosmological consequences of these theories is that rather than the universe expanding as in the big bang theory, instead time is steadily speeding up as the universe’s gravitational potential steadily increases from zero (at the time that the universe was created). Time speeding up can also be interpreted as a steady decrease in the speed of gravity and light, and this theory has been analyzed at great length by Louise Riofrio, whose theories are compatible with the CMB temperature correlations.
Finally, Lubos Motl‘s beautiful analysis of the vibrations of black holes suggests that there is something wrong with the spin-statistics theorem, (the division of elementary particles into Bose-Einstein or Fermi-Dirac camps) this suggests a preon model with elements similar to those implied by the Feynman checkerboard model; bit from trit.