The Cosmological Constant

Abstract

This is a review of the physics and cosmology of the cosmological constant. Focusing on recent developments, I present a pedagogical overview of cosmology in the presence of a cosmological constant, observational constraints on its magnitude, and the physics of a small (and potentially nonzero) vacuum energy.

Comments: 50 pages. Submitted to Living Reviews in Relativity (http://www.livingreviews.org/), December 1999