Problems of measurement of the Newtonian gravitational constant

Due to weakness of gravity, the accuracy of the Newtonian gravitational constant G is essentially below the accuracy of other fundamental constants. The current value of G, recommended by CODATA in 2006, based on all results available at the end of 2006, is G = (6.67428 ± 0.00067) × 10−11 m3 kg−1 s−2 with a relative error of 100 ppm. New experiments at a level of accuracy of 10 to 30 ppm are now in progress in some world gravitational laboratories. One of the problems of improving the accuracy of G is a precision measurement of the period of eigen oscillations of the torsion balance. In this work, numerical modelling of torsion and swing oscillations is under the condition that the torsion system is subject to randomnoise. A newmethod of high-precision estimation of the period of torsion oscillations has been developed. The dependence of the torsion period value and the error of its estimation on the level of the acting seismic noise has been studied. To measure the Newtonian gravitational constant at the accuracy level of 10 ppm, the environmental seismic noise must be below 10−2 mGal.