This is an answer to Jacob Navia.

Back when people readily embraced the very idealistic version of the
Big Bang paradigm (in which the entire Universe, including all space
and time, was created in the BB), the CMB was interpreted by many as
virtually an absolute reference frame. This, of course, would appear
to violate the foundations of relativity theory, which unequivocally
rejects Newton's hypotheses of absolute space and absolute time.

However, more recently cosmologists have begun to adjust to the
alternative paradigm that the observable universe, and the CMB that
goes along with it, are just a drop in the proverbial bucket. Various
Multiverse theories, Eternal Inflation and the remarkable new results
of Kashlinsky et al (see SAR: "Dark Flow and Homogeneity", Nov. 1) are
the first hints of a new paradigm for the 21st century. In this
paradigm, the CMB [with its growing list of blemishes] is definitely
not a true universal background, far less an absolute reference frame.
Relativity is safe for now and probably will remain so for quite some
time, that is, as long as we let observations resolve scientific
issues.

Yours in science,
Knecht
www.amherst.edu/~rloldershaw