Toward the Determination of $G$ With a Simple Pendulum

An experiment aimed at the determination of the constant G was started in 1995 at the Politecnico di Torino, Torino, Italy, based on measurement of the period of a simple pendulum. Two source masses are periodically moved, orthogonally to the swinging plane, between two fixed positions. An optical system detects the pendulum perigee, and an electronic circuit measures the period. This paper describes recent progress and results, in which an unexpected effect, which is currently under investigation, limits the desired 10
^-4
uncertainty level to 3.2%