Although matter is postulated to be very sparse in the Fatio-Le Sage theory, it cannot be perfectly transparent, because in that case no gravitational force would exist. However, the lack of perfect transparency leads to problems: with sufficient mass the amount of shading produced by two pieces of matter becomes less than the sum of the shading that each of them would produce separately, due to the overlap of their shadows (P10, above). This hypothetical effect, called gravitational shielding, implies that addition of matter does not result in a direct proportional increase in the gravitational mass. Therefore, in order to be viable, Fatio and Le Sage postulated that the shielding effect is so small as to be undetectable, which requires that the interaction cross-section of matter must be extremely small (P10, below). This places an extremely high lower-bound on the intensity of the flux required to produce the observed force of gravity. Any form of gravitational shielding would represent a violation of the equivalence principle, and would be inconsistent with the extremely precise null result observed in the Eötvös experiment and its successors — all of which have instead confirmed the precise equivalence of active and passive gravitational mass with inertial mass that was predicted by general relativity. For more historical information on the connection between gravitational shielding and Le Sage gravity, see Martins, and Borzeszkowski et al.
Since Isenkrahe's proposal on the connection between density, temperature and weight was based purely on the anticipated effects of changes in material density, and since temperature at a given density can be increased or decreased, Isenkrahe's comments do not imply any fundamental relation between temperature and gravitation. (There actually is a relation between temperature and gravitation, as well as between binding energy and gravitation, but these actual effects have nothing to do with Isenkrahe's proposal. See the section below on "Coupling to Energy".) Regarding the prediction of a relation between gravitation and density, all experimental evidence indicates that there is no such relation.
Other articles related to "gravitational shielding":
... view of the scientific community is that gravitational shielding does not exist, but there have been occasional investigations into this topic, such the 1999 NASA-funded ... Wu indicated various applications of quantum gravity theory could allow gravitational shielding phenomena ...
Famous quotes containing the word shielding:
“The ultimate result of shielding men from the effects of folly, is to fill the world with fools.”
—Herbert Spencer (18201903)