Why is G the Least Precisely Known Physical Constant?

Abstract

CODATA has recently published its readjustment of the fundamental physical constants and assigns a relative precision of 128 × 10−6 to G, the Newtonian constant of gravitation. Given that most of the other constants in physics have relative precisions of ∽ 10−6 or better, we examine the reasons why the value for G remains so imprecise: The role of G in physics in general is considered and the most recent experimental determinations are examined. Constraints are given for perturbing effects in G measurements and a key result is that horizontal ground movements must be taken more carefully into account in future more precise terrestrial experiments. © 1987, Walter de Gruyter. All rights reserved.