The Terrestrial Measurement of Relativistic Frame-dragging

This is a laboratory scale Foucault pendulum which operates continually under electromagnetic drive. This instrumented high-performance Foucault pendulum forms the basis of an experiment that is intended to measure the Lense-Thirring precessional motion of a test mass - the pendulum bob - in the vicinity of a massive rotating body which in this case is the Earth. This tiny precessional motion, which is to be detected on top of the Foucault precession over time, is a consequence of the dragging of spacetime and is predicted by Einstein’s theory of General Relativity. Frame-dragging is an inherent feature of gravitation and to date two accurate measurements have been made of this effect in low Earth orbit, but the effect has not yet been measured on the Earth.