Published in EOS Trans. AGU 76(46):F62, November 7, 1995, Poster U42-20, Abstract Only
The Geophysical Test of a Theory of Relativity
Geophysical measurements, in comparison to the Earth's rotation and velocity relative to astronomical entities, have been used to test various alternative theories of gravitation. In particular, one of the most serious contenders, Whitehead's theory, was shown to be invalid by an analysis of the tidal record, in a test beyond the reach of laboratory measurements. Whitehead's theory is the tensor analogue of the electromagnetic vector equations, and it incorporates a flat background metric. It predicts the same values as Einstein's theory for other observables, including black holes. Though it is nearly as elegant as Einstein's, it apparently predicted a large gravitational anisotropy which would result in gravity tides, with a 12 hour sidereal period, that are not observed (see discussion by Moritz in Quo Vadimus, Garland and Apel, eds., AGU, 1990).
This prediction may be invalid, and Whitehead's theory appears to deserve additional consideration. The factors of Whitehead's theory that predict the unobserved tides are proportional to the value M/R, where M is the mass of an astronomical entity, and R is its distance from Earth. The mass of the galactic center was used to calculate the predicted tides, as the galactic M/R value overwhelms any value from within the Solar System. Measurements of extragalactic mass concentrations, such as the Virgo supercluster and the Great Attractor, produce similar M/R values, however, and in different directions. M/R may be distributed evenly throughout the celestial sphere, an assumption that is often made. Whitehead's theory then would not predict a large gravitational anisotropy, and might remain a viable alternative to General Relativity.