al. Also, for a discussion of recent observations during solar eclipses, see the paper by Unnikrishnan et al. Majorana's experiments and Russell's criticism Some shielding experiments were conducted in the early 20th century by Quirino Majorana. Majorana claimed to have measured positive shielding effects. Henry Norris Russell's analysis of the tidal forces showed that Majorana's positive results had nothing to do with gravitational shielding. To bring Majorana's experiments in accordance with the equivalence principle of General Relativity he proposed a model, in which the mass of a body is diminished by the proximity of another body, but he denied any connection between gravitational shielding and his proposal of mass variation. For another explanation of Majorana's experiments, see Coïsson et al. But Majorana's results couldn't be confirmed up to this day (see the section above) and Russell's mass variation theory, although meant as a modification of general relativity, is inconsistent with standard physics as well. Minority views The consensus view of the scientific community is that gravitational shielding does not exist, but there have been occasional investigations into this topic, such as the 1999 NASA-funded paper which reported negative results. Eugene Podkletnov claimed in two papers, one of which he later withdrew, that objects held above a magnetically-levitated, superconducting, rotating disc underwent a reduction of between 0.5 and 2% in weight. Theoreticians have attempted to reconcile Podkletnov's claims with quantum gravity theory. However, neither Podkletnov's claims, nor the similar claims of others, of "gravity reduction", "gravity shielding", or the like, have yet been successfully replicated, verified by independent review, or subjected to public demonstration. Electrets In his 1976 paper, Electromagnetism and Gravitation, physicist Edward Teller discussed experimentation with electrets, or materials with a permanent electric dipole moment, near its transition point to discover the transition between dipole states. On July 9, 1997, William Rhodes, an inventor, made a posting on Usenet concerning a discovery of an antigravity effect related to electrets. Also, Dr. Martin Tajmar, a physicist and professor for Space Systems at the Dresden University of Technology has written a paper on propellantless propulsion and makes numerous references to electrets. A patent for a gravitational attenuating material that utilizes an organic based material was made by inventor Ronald J. Kita. See also Breakthrough Propulsion Physics Program Anti-gravity Artificial gravity Eugene Podkletnov Ning Li Electromagnetic shielding References External links Anti-gravity General relativity Science fiction themes Fringe physics Pseudoscience