Note on the Repetition of the Michelson-Morley Experiment

The CMB, Preferred Reference System, and Dragging of Light in the Earth Frame

“…Namely, what could be the physical mechanism that, starting from a fundamental 10 −15 vacuum signal, enhances the effect up to 10 −11 and 10 −10 in gaseous helium and air, respectively, and finally disappears in solid dielectrics, as in the very precise cryogenic experiment in sapphire, which also gave the same 10 −15 as in vacuum? Our answer to this question in Section 6 was based on the traditional interpretation [44,45] of the old residuals in terms of a small temperature difference ∆T gas (θ) of a millikelvin or so between the optical arms. These differences could induce convective currents of the gas molecules and a small angular dependence of the refractive index.…”

“…Note the agreement of the two determinations obtained in very different conditions (the basement of the Cleveland laboratory or the top of Mount Wilson). This shows that the traditional interpretation [44,45] of the residuals as temperature differences in the optical paths is only acceptable provided that these temperature differences have a non-local origin. We will return to this point in Section 6.…”

“…This previous analysis suggests two considerations. First, the old estimates of about 1 mK by Kennedy, Shankland, and Joos (see [44,45]) were slightly too large. Within our present view, this may indicate that the interactions of the gas molecules with the CMB photons are so weak that, on average, only less than 1/10 of ∆T CMB (θ) is transferred to the gas in the optical paths.…”

“…As a hint, we recall that Equation ( 8) was originally deduced in [18] as the most general angular dependence of the refractive index in the presence of convective currents of the gas molecules generated by an Earth velocity v. This idea of convection with respect to the container of the gas at rest in the laboratory leads to the reconsideration of the traditional explanation of the small residuals in terms of tiny temperature differences of a millikelvin or so [44,45]. The interesting aspect is that, aside from helping our intuition, this thermal interpretation will, in the end, be useful in analyzing the complementary region of the refractive index N , which is very different from unity, as in solid dielectrics.…”

“…This is in contrast with the Shamir-Fox [43] experiment in perspex, where the observed value was smaller by orders of magnitude. Then, as an alternative possibility, in Section 6, we review the traditional thermal interpretation [44,45] of the residuals in gaseous media. The idea was that, in a weakly bound system as a gas, a small temperature difference ∆T gas (θ) of a millikelvin or so between the optical arms could induce convective currents in the gas and, in turn, angular differences in the refractive index proportional to gas ∆T gas (θ)/T, where T ∼ 300 K is the temperature of the laboratory.…”