Independence of the gravitational constant from gross Earth data

Abstract

Determination of the Newtonian gravitational constant G from free oscillation and travel-time data for a spherically symmetric non-rotating Earth is shown to be inherently impossible as long as G is spatially constant. Since Earth densities are normalised by the laboratory value of G, one consequence is that the accuracy of the density and elastic parameters derived from inversion of such data is limited to the accuracy of G. Another is the derivation of closer geophysical limits on any intermediate range variation of G than previously reported. Although these limits are not reliable if G changes in the 10-1000 km range, a significant variation of G in this range should be detectable from free oscillation and travel-time inversions. Show more