Miller’s experiments : a relativistic controversy

Between 1902 and 1926, Dayton C. Miller (1866-1941) made several ether-drift experiments similar to the more famous 1887 Michelson-Morley one. Miller’s results, on the contrary of Michelson-Morley’s ones, showed a periodic second-order effect that he interpreted as a proof of the absolute motion of the Earth. Since the fringes shift he measured corresponded to a velocity of the Earth lower than the one expected in a fixed-ether theory, he argued the existence of an ether entrained by the Earth. In 1925, Einstein himself wrote in a letter to Edwin Slosson: “Should the positive result be confirmed, the special theory of relativity and with it the general theory of relativity in its current form would be invalidate […]”. Miller’s data were explained in the context of the relativistic research program only in 1955 by Shankland, McCukey, Leone and Kuerti. My study has the aim to broaden the understanding of what happened between 1925 and 1955: 1)Knowledge and interpretation of Miller’s data inside the international physics community; 2)Why Miller’s experiments didn’t become experimenta crucis against Einstein theories. The themes I am willing to analyze are important in developing the history of relativity and for their raising interesting epistemological questions about the theory-experiments relationship.