The Michelson-Morley experiment is supposed to be able to detect a time difference between the paths of light in a parallel and in a perpendicular path to the aether wind, both two-way paths of the same length. It is argued that, if such time difference exists, it will be revealed as a phase shift between both reflected light beams. Actually a phase difference does not appear, which leads to the conclusion that the aether does not exist and that the speed of light must be constant on both paths. Now, in the following paper, http://xxx.lanl.gov/ftp/physics/papers/0401/0401092.pdf the author argues that, although a time difference may exist, the MM experiment does not reveal it: no phase shift is produced, since the number of periods of light travelling thought the first path is always the same as the number of periods of light travelling thought the second path (taking into account the doppler effect). The paper concludes that the MM interferometer is ‘blind’ to speed. To me the calculations for the number of periods in the parallel and perpendicular paths done in chapter 2.d. seam to be correct (assuming of course that special relativity is invalid, as it is done before performing the MM experiment). Is this actually a known problem or may be there are some errors in the paper? Any comments? Thanks. Regards.