2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/175342Up to now, Dark Energy evidences are based on the dynamics of the universe on very large scales, above 1 Gpc. Assuming it continues to behave like a cosmological constant $Λ$ on much smaller scales, I discuss its effects on the motion of non-relativistic test-particles in a weak gravitational field and I propose a way to detect evidences of $Λ\neq 0$ at the scale of about 1 Mpc: the main ingredient is the measurement of galaxy cluster masses.5 pages, no figures, references addedAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext