Gravitational shielding

The shielding of gravity (also absorption of gravitation ) is a hypothetical process in which an object against the influence of the gravitational field - is shielded, which should lead to a reduction in the weight of the object - at least partially. No recognized by experts and repeatedly reproduced experiment has so far successfully provide positive screening results. According to current knowledge, any shielding of the gravitational contradicts the equivalence principle of general relativity by Albert Einstein, which has so far been confirmed in all experiments.

Tests of the equivalence principle

To quantify the magnitude of the shield, hit Quirino Majorana in front of the coefficient h, which is intended to modify Newton's law of gravitation in the following way:

The best laboratory measurements have shown an upper limit of 4.3 × 10-15 shield m² / kg. However, astronomical observations suggest a much more stringent limit. Based on observations of the moon's orbit from 1908, Henri Poincaré determined that h must not be greater than 10-18 m² / kg. Also, this limit has now been clarified. Eckhardt (1990) set an upper limit of 10-22 m² / kg, and Williams, et al, (2006 ) have the H = (3 ± 5) × 10-22 m increases / kg, which value is smaller than the measurement uncertainty. For an overview of the current experimental limits see Bertolami et al.

The consequence of these negative results (which are in good agreement with the general theory of relativity are ) is that any theory which includes a general screening of gravitation, is such as Le Sage gravitation, refuted or that effect on a must reduce immeasurable size.

Majorana's experiments and Russell's criticism

Quirino Majorana in 1920 led several experiments, and maintained a positive screening result to have rendered. Since Majorana was a well known and respected experimental physicist, Henry Norris Russell elaborated on these results. He pointed out that these results may have nothing to do with a shield of gravitation in his opinion, would otherwise be under use of Majorana value for h, the stands of the Tides on the opposite part of the world only half as high as in of the sun -facing side.

If Majorana measurement results are not due to measurement error, must be sought for another explanation, according to Russell. He therefore proposed a modification of the general relativity theory (ART), according to which the mass of a body in the vicinity of another body to lose weight and would thereby preserving the principle of equivalence. Russell emphasized, however, that this mass variation is not to be understood as a shield of gravitation. Russell's theory of Massenveränderlichkeit for ART is not accepted by the experts.

However, an exact reproduction of the exact experimental setup of Majorana not yet available, will continue to speculate. The negative results in the review of the equivalence principle (see description above) leave in the professional world a gravitationally induced effects appear unlikely. See, eg, Declaration of Coïsson et al., Which indeed believe in the positive outcome of the experiment, however, reject any connection with a shield of gravitation.

For a historical overview of the attempts to prove a shield of gravitation, see the article by Martins.

Perspectives outside the mainstream

Although such concepts are largely rejected, financed, for example, NASA continues to research in that direction.

A certain level of recognition have also the shield experiments by Yevgeny Podkletnow with rotating superconductors, which are said to be have been positive, with a variation in weight of 0.5 to 2%. This is many times more than what was stated as the upper limit for the tests of the equivalence principle. Podkletnovs results and justifications are therefore not accepted by the professional world and could not be confirmed by various experimenters. The supposedly measured by effect it is also known as anti-gravity.