Flaws in the ether-drift experiments, nature of light and hydrodynamic features of the ether: possible role of a dilatant vacuum.

By now, it has become clear that space cannot be treated as mere geometry if we want to achieve a theory of quantum gravity. Evidences from cosmology, dark sector, quantum vacuum, Higgs field and, recently, also dilatant vacuum, suggest that physical vacuum may be endowed with hydrodynamic properties but this contrasts with the null result of the Michelson-Morley experiment and of subsequent tests, which have excluded any dark fluid permeating all space. This is the reason for this new review of the ether-drift experiments, starting from the Michelson-Morley. This analysis shows major flaws in these experiments. The velocity of an apparatus with respect to the stationary ether is more complex to define; apparent ether wind has been confused with ether wind; the transverse path observed in the frame of the ether has not been correctly thought of and invalidates the length-contraction solution to the null result of the Michelson-Morley experiment, which is rather due to the unchanged delta after rotation. The investigation continues by pointing out that thinking of a generic ether can be misleading and specific hydrodynamic properties of the vacuum, as for instance its dilatancy, have to be defined and might explain at the same time both the nature of light and the null results of the ether-drift experiments after the Michelson-Morley, eventually giving a quantum basis to special relativity.