Harvard University Department of Astronomy

The Cosmological Constant Cosmic Microwave Background Basic Idea: scale on the sky given by horizon/sound speed at recombination. Angular scale it subtends today tells us about spatial curvature. Recap of relation: fixed ruler -> spatial curvature System of interest: temperature anisotropies of CMB photons from the big bang provide a ruler What they are: State of the universe at 300,000 years old Cosmic microwave background: best black body spectrum in nature Anisotropies: relevant scales and players acoustic waves, why calculation under good control Position of the first peak Observations Recent results: Boomerang and MAXIMA Future measurements foregrounds expected sensitivity and parameter dependence Note also weak test of lambda directly Other cosmological tests CMB is used for Other suggested test of angular size Some References Home Syllabus References Lecture References Useful Links Contact Info