Absolute measurement of the Newtonian force and a determination of<i>G</i>

Abstract

We present the status and preliminary results of the Wuppertal gravitational experiment which is based on a microwave resonator. The gravitational force of two test masses acting on the resonator is measured as a function of distance. From new data taken recently we determine the gravitational constant G and test Newton's inverse square law in a distance range between 0.7 m and 2.2 m. From our measurements we obtain a preliminary value for G = 6.6735 × 10-11 m3 kg-1 s-2 with an uncertainty of 432 ppm dominated by systematic considerations.