2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198225We analyse the effects of thermal conduction in a relativistic fluid, just after its departure from hydrostatic equilibrium, on a time scale of the order of thermal relaxation time. It is obtained that the resulting evolution will critically depend on a parameter defined in terms of thermodynamic variables, which is constrained by causality requirements.16 pages, emTex (LaTex 2.09). To appear in Classical and Quantum GravityGeneral Relativity and Quantum CosmologyAstrophysicstext