No. 17: Fall 1981
For too many years, physicists have been content with laboratory determinations of G (the gravitational constant) using the old Cavendish Balance. In this paper, Stacey and Tuck offer a disturbing collection of values of G determined from geophysical measurements; i.e., measurements in mines, boreholes, and under the sea. These measurements are unanimous in producing G's that are larger than the usually accepted value by about 1%. Furthermore, the deeper the experiment, the greater the departure from the standard value.
(Stacey, F.D., and Tuck, G.J.; "Geophysical Evidence for Non-Newtonian Gravity," Nature, 292:230, 1981.)
Comment. These geophysical measurements must be added to recent laboratory experiments indicating that gravity may not be best described by an inverse square law. See our Handbook Mysterious Universe. Ordering details here.