Data from the Planck Telescope published in 2013 has since found stronger evidence for the anisotropy. "For a long time, part of the community was hoping that this would go away, but it hasn’t," says Dominik Schwarz of the University of Bielefeld in Germany.
https://en.wikipedia.org/wiki/Axis_of_evil_(cosmology)
Anisotropy means not the same in all directions, the opposite of isotropy. The universe may not be the same in all directions, after all, ie, there may be a center to it. Then Relativity Theory might not be so basic, as opposed to Quantum Theory, or even completely correct.
There's not much support for the notion that the speed of light fluctuates, anymore, because that, and some other things, make up the fine-structure constant of the universe, a dimensionless number that may be the most basic number of all in physics, where "the rubber hits the road" with matter and field. It has, more or less, been proved to be constant, although no one knows how to write that number algebraically. So, Relativity Theory can't be too far off correct if the speed of light remains constant (depending on what it passes through.)
I'm taking a little break from my own "theory of everything" to catch up on a lot of other work. Hands tied. However, these are great times to play (rest) with what I call "fun" numbers, numbers that together seem to form their own little mathematical "field" of numbers, but connect to nothing logical. You have to figure that there are all sorts of non-numerical meanings of numbers too, beyond just writing, eg, 3 as three. Different ways for numbers to be "numbers but not". And, that some of the really important numbers in math and physics would be more than just numbers. There are many paradoxes involved with summing up a universe. How else to overcome any of those?
Today, I noticed that 411 = 3 X 137, and 137 = 4^2 + 11^2, a Pythagorean prime. The inverse of 137 is rather close to the fine-structure constant. The number that a famous physicist told his students to put up on their wall. It has a sort of "cult following" among theoretical physics, as well. Notice how the 4 and 11 make up the 137, and, versa, how the 137 makes up the 411. You would have to go to the other site to see the significance of the 411. (If we are the 42nd dimension, then the 41st, which in a way comes before and after us, is our "tracks".) Then 41 + 1 ---> 411 comes from trying to add 1 to the 41, on the end, but after the end. Sort of a limit after the limit. How do we become our "tracks", which are beneath our matter and fields? Does the fine-structure constant remain constant between "different" universes? Is it actually somehow just, exactly 1 / 137?