On Experimental Tests of the General Theory of Relativity

This paper explores the extent to which the three “crucial tests” support the full structure of the general theory of relativity, and do not merely verify the equivalence principle and the special theory of relativity, which are well established by other experimental evidence. It is shown how the first-order changes in the periods of identically constructed clocks and the lengths of identically constructed measuring rods can be found without using general relativity, and how the red shift and the deflection of light can be computed from them. Only the planetary orbit precession provides a real test of general relativity. Terrestrial or satellite experiments that would go beyond supplying corroborative evidence for the equivalence principle and special relativity would be extremely difficult to perform, and would, for example, require a frequency standard with an accuracy somewhat better than one part in 1018.