Year: 2013 Pages: 6
Determination of the motion of our earth relative to external frames of reference is a non-trivial task. Some theoreticians of the past, like Poincaré, declared it was impossible to measure the absolute motion of the Earth by experiments carried out here. Nonetheless, during the past century, observational astronomers, physicists and engineers managed to estimate the terrestrial motion relative to several external frames. The present paper lists such results, starting with Courvoisier and Esclangon data from the 1920s, and ending with the author’s own work during the past decade. The right ascension/longitude of reported motions, including the COBE data, was plotted in galactic, equatorial and ecliptic systems of coordinates. The points are scattered in galactic coordinates, thus indicating that solar motion relative to extra-galactic frames does not consistently affect our experiments/observations on earth. On the contrary, data plotted on equatorial coordinates seem to separate into two groups: (1) Data obtained by optical and mechanical methods, and by astronomical observation involving reflection of light, which cluster around a unique plane, and (2) Data obtained by the COBE and Smoot’s earlier data, thus suggesting two different mechanisms at work. The plot in ecliptic coordinates makes it evident that the data obtained by Esclangon, Courvoisier and Múnera is closely related to the strong radio source and/or blackhole at the center of our galaxy. The procedure used by the author to extract the value of solar velocity from his two year Michelson-Morley experiment with stationary interferometer is briefly outlined. From that velocity the known solar motion relative to our galaxy is substracted: tangential motion around the center of the Milky Way, and nutation relative to the galactic plane. The residual velocity is reported, followed by a brief concluding discussion.