The Seemingly Preferred Cosmic Frame

Abstract The Universe appears to have a `preferred' frame of reference, within which the cosmic microwave background is completely isotropic. Earth's motion through this relic radiation field measurable, and some viewed type observation as possible contradiction Einstein's principle relativity. Several experiments been proposed (and carried out) test for violations Lorentz invariance when transforming out frame, e.g., based on expected velocity differences in Michelson-Morley probe. But what exactly frame? Is it truly an absolute attached Universe, or observer-dependent construction? Such possibilities represent very different Physics, course. In paper, we work these issues carefully, without introduction unsubstantiated assumptions. We show that preferred frames originate general (not special) relativity, are indeed observer-dependent. Their existence does not at all conflict with fundamental hypothesis special