[vannrox]

There is a great paper whereas the four-dimensional universe on the TeV brane of the Randall-Sundrum scenario takes the bimetric structure of Clayton and Moffat, with gravitons traveling faster than photons instead, while the radion varies with time.

!!!!!!!!!!!!

The paper shows that such brane world bimetric model can thereby solve the flatness and the cosmological constant problems, provided the speed of a graviton decreases to the present day value rapidly enough. The resolution of other cosmological problems such as the horizon problem and the monopole problem requires supplementation by inflation, which may be achieved by the radion field provided the radion potential satisfies the slow-roll approximation.

A variable gravitational constant would inherently indicate a variable light constant.

[RadioAstronomer]

Check this out:

http://www.sciencedaily.com/releases/2005/04/050418204410.htm