Testing the inverse-square law of gravity on a 465-m tower.

Abstract

We have performed a test of Newton's universal theory of gravitation by comparing gravity measured on a tower to an upward continuation of the surface gravity field. We measured gravity at 12 heights on a 465-m tower at the Nevada Test Site and, in addition, made measurements at 281 locations on the ground. The surface points fell within 91 optimally chosen sectors that extended out to 2.6 km from the tower. These data were combined with 60 000 additional surface gravity measurements within 300 km of the tower. We used a surface integral derived from Laplace's equation to upward continue the surface gravity field and our observations are consistent with the Newtonian predictions to within (-60\ifmmode\pm\else\textpm\fi{}95)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$ m ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}2}$ at the top of the tower.