New Constraints on Varying Alpha

Abstract

I briefly present some current theoretical motivations for time or space variations of the fundamental constants of nature and review current key observational results. I focus on the fine-structure constant, and particularly on measurements using quasars and the cosmic microwave background. I also compare various observational results to the simplest model-building expectations.

8 pages, review talk at the XXXIX Rencontres de Moriond (La Thuile, March 2004), to appear in the proceedings