Quintessence and Cosmic Microwave Background

Abstract

Analytic 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 ${\Omega }_M$ and ${\Lambda }_{\Lambda }$, 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, 2000