Old and New Approaches in the Study of Gravitational Absorption

1. Many efforts, both theoretical and experimental, and astronomical studies on the motion of celestial bodies have been made in the past in an attempt to detect a possible effect of gravitational absorption. To the astronomical studies belongs Russell’s approach in which any celestial body is assumed to absorb a fraction of its own gravitation, which leads to the nonproportionality of inertial and gravitational masses and to the failure of Kepler’s third law (Russell 1921). Following a similar approach, Bottlinger considered the perturbations due to gravitational lunar eclipses on the Moon’s motion, assuming the Sun as the gravitational source, the Earth as the screen and the Moon as the probe (Bottlinger 1912). In laboratory experimentation, Majorana’s research is to be mentioned, aiming at the determination of an upper limit of the absorption coefficient, assuming the Earth as the gravitational source, a very sensitive balance as the detector, and heavy masses as screens (Majorana 1919). Worth mentioning is Tomaschek’s research in which gravity meters are used to detect a possible non-symmetric distribution of the tidal forces assuming the Moon as the source and the Earth as the screen (Tomaschek 1954). In the same approach an upper limit of the absorption coefficient has been determined assuming the Sun as the source and the Moon as the screen during total solar eclipses using gravity meters and horizontal pendulums as sensors (Caputo 1962). 2. The purpose of the present letter is to summarize an attempt to evaluate the absorptional effect assuming the Moon as the source, the Earth as the screen and an artificial satellite as the probe. It appears that the computed perturbations are very small and beyond the possibility of detection. In this attempt we have assumed that the gravitational effects are attenuated by the presence of interposed matter along the trajectory of the gravitational ‘ ray ’ according to the law