2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/2512Analytic formulas for the position of the first acoustic peak in the CMB are derived and discussed. They are generalized to the case of a time-dependent dark energy component and it is shown how the cosmic parameters $Ω_M$ and $Λ_Λ$, extracted from observations, have an intrinsic uncertainty until one knows whether the dark energy density is, or is not, time dependent.17 pages LaTeX. Invited talk at ORBIS-2000, Fort Lauderdale,Fl. December 14-17, 2000AstrophysicsHigh Energy Physics - Phenomenologytext