2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/33641The vorticity of a congruence is often considered to be the rate of rotation for the precession of a gyroscope moving along a world-line belonging to that congruence. Our aim here was to determine the evolution equation for the angular momentum of a gyrosocope with respect to an arbitrary time-like congruence: i.e, a reference congruence not containing the curve described by the gyroscope. In particular, we show the specific conditions needed to support the introductory statement about the vorticity. We thus establish a well-founded theoretical description for the analysis of the precession of gyroscopes, providing suitable conclusions for possible experiments.18 pages, TeX. Corrected typos. New tittleGeneral Relativity and Quantum Cosmologytext