Redetermination of the Newtonian Gravitational Constant<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>G</mml:mi></mml:math>

Abstract

The universal Newtonian gravitational constant is being redetermined at the National Bureau of Standards with use of the method of Boyes in which the period of a torsion pendulum is altered by the presence of two 10.5-kg tungsten balls. The difference in the squares of the frequencies with and without the balls is proportional to $G$. The resulting value of $G$ is (6.6726\ifmmode\pm\else\textpm\fi{}0.0005)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}11}$ ${\mathrm{m}}^{3}$\ifmmode\cdot\else\textperiodcentered\fi{} ${\mathrm{sec}}^{\ensuremath{-}2}$\ifmmode\cdot\else\textperiodcentered\fi{} ${\mathrm{kg}}^{\ensuremath{-}1}$\ifmmode\cdot\else\textperiodcentered\fi{}