Determination of the gravitational constant by an experiment at a pumped-storage reservoir

Abstract

In August 1988 continuous gravity measurements were made in a pumped-storage reservoir in SW Germany. Daily water-level variations of 5--22 m produced, together with the tides, a quasiperiodic gravity signal which could be measured with a resolution well below 1 \ensuremath{\mu}gal${=10}^{\mathrm{\ensuremath{-}}8}$ m ${\mathrm{s}}^{\mathrm{\ensuremath{-}}2}$. The experiment's goal was a search for deviations from Newton's gravitational law, but it can also be viewed as a measurement of the gravitational constant G for effective mass distances of 40--70 m. The deviation of G from the laboratory value was found to be (0.25\ifmmode\pm\else\textpm\fi{}0.4)% and thus is not significantly different from zero.