The cosmic microwave background (CMB) provides a snapshot of the early
Universe when matter began to become structured and has been the focus of
several recent observational campaigns. In this Perspective, we discuss the
results from these campaigns, which provide support for inflationary models of
the Universe.Comment: Perspective: Cosmology. See summary at
http://www.sciencemag.org/cgi/content/summary/291/5505/837 (need sign up) or
full text (free) at http://www.iafe.uba.ar/relatividad/gangui
