This experiment will measure the Newtonian gravitational constant, G, on scale lengths of 100 m to 1500 m, to an accuracy of 1 part in 1000 or better. The intent of the experiment is to search for possible scale length variations in G that have been hypothesized in an effort to produce a unified field theory in modern physics. If a scale length variation exists it will verify the existence of a fifth force of nature (about which there has been much recent publicity) and will have a significant effect on many branches of modern physics including general relativity, unified field theory, astrophysics, and cosmology. The proposed experiment consists of measuring the difference in gravity between the top and bottom of the greenland continental ice sheet through a borehole at Dye 3 using a LaCoste & Romberg borehole gravity meter. By measuring the acceleration of gravity, the depth interval of the experiment, and the density of the ice, G can be calculated. Others have found anomalous variations in gravity with depth in mines that could be explained by allowing G to be greater than the laboratory value by almost 1%. Uncertainty in the density of rock near mines makes this result inconclusive, Because the density of ice is much better known, the experiment proposed here will be much more accurate than any previous geophysical measurement of G. This investigation is also being supported by: The NSF Division of Physics, the Air Force Geophysics Laboratory, Amoco Production Co., and the Los Alamos National Laboratory.
