In a recent post about reference frames in the universe and the cosmic microwave background, my friend and fellow astronomer recently wrote:
This "dipole" signature in the cosmic microwave background represents our motion (mostly the Milky Way's motion) through this omnipresent gas of photons left over from the explosion that created the Universe. This means that the stuff in the Universe does have a preferred frame of reference, even if the laws of the Universe don't. Crazy. Sometimes I wonder: how did the Universe pick that frame? Other times I wonder whether that question has any meaning at all. Other times I wonder which of those wonderings is more profound. Then I get back to changing my daughter's diaper and my priorities are rightfully restored.Well stated!