Investigating variations in the gravitational constant
In August–September 1987 a group of geophysicists, led by M. Ander of the Los Alamos National Laboratory and M. Zumberge of Scripps Institution of Oceanography, performed a geophysical experiment to determine the value of the gravitational constant, G. Using the DYE-3 borehole on the Greenland ice cap, the experiment was intended to provide evidence concerning possible scale variations in G, and thus for non-Newtonian gravity. This report describes the background to the experiment and the radio echo-sounding survey carried out to provide terrain corrections for the gravity model. The experiment showed values of G differing from laboratory determinations by margins which considerably exceed experimental error.