Center of the universe.

Okay, so we know the speed of light.
We also assume that the universe is expanding.
(I'm going to assume for the moment that that assumption is fact.)

Given these two bits of information, it should be possible, through the observation of the speed of light in various directions, to determine not only our relative velocity traveling away from the mass center of the universe, but also to pinpoint the direction to the mass center of the universe.

If light speed is a constant. It would have to be using everything as a reference point. Everything, being the universe in total.

Hence, if you observe light traveling in a direction away from the center of the universe, while we are also traveling away from the center of the universe, the speed of light 'should' become the speed of light minus our velocity from the center of the universe.

In the opposing direction, you should observe that light traveling toward the center of the universes mass, would become the speed of light, plus our velocity as we travel from the center of the universe.

Hence, light speed should vary relative to earths velocity.

I have no means to test this of course. But it's worth pondering.

One would of course have to take into account earths rotation around the sun, our own spin, and any "wobble" that might be caused by the moon, and other objects.
But the resulting discrepancy in the speed of light in different directions after the fact, should be the velocity at which we (our solar system) is traveling away from the mass center of the universe. And the direction of observation that yields the greatest discrepancy should indicate to us which direction the mass center of the universe is.

Should it not?

--Update--

So, I didn't exactly think far enough into this. Essentially, after a few hours of scribbling out the details... turns out I came to the same realization as many other former theorists... light travels the same speed in all directions relative to the observer.

... well... crap.
If I had picked up some reading material, instead of trying to "re-invent the wheel" I could have saved myself allot of time.