Unaccounted source of systematic errors in measurements of the Newtonian gravitational constant G

•Source of discrepancies on universal gravitational constant G measurements.•Collective motion of dislocations results in breakdown of Hook's law.•Self-organized criticality produce non-predictive shifts of equilibrium point.•New dissipation mechanism different from loss angle and viscous models is necessary.•Mitigation measures proposed may bring coherence to the measurements of G.

Many precision measurements of G have produced a spread of results incompatible with measurement errors. Clearly an unknown source of systematic errors is at work. It is proposed here that most of the discrepancies derive from subtle deviations from Hooke's law, caused by avalanches of entangled dislocations. The idea is supported by deviations from linearity reported by experimenters measuring G, similarly to what is observed, on a larger scale, in low-frequency spring oscillators. Some mitigating experimental apparatus modifications are suggested.