Albert Einsten's Relativities considere that all acelerations are relative. However according to Mach, absolute acelerations might by observed if the hole universal mass distribution could be detained. According to Marcelo Samuel Berman, such relativity and absolutism can co-exist within General Relativity Theory, if the universal rotation is considered. Experimental verification includes rotation of the Polarization of the cosmic background microwave radiation seems the Big Bang, as well the recente observations on the deceleration of the Pioneer Space Probes, as observed by NASA. The so-called Pioneer Anomaly can be considered as centripedal deceleration from the rotation of the Universe.
↑Marcelo Samuel Berman, Realization Of Einsteins Machian Program (Nova Science Publishers, New York 2012)