THE PHYSICS OF MICROWAVE BACKGROUND ANISOTROPIES

The residual radiation from the Big Bang is observable as the cosmic m icrowave background-a near-uniform sea of photons with an average temp erature of 2.7 K. Small variations in the temperature of the microwave background reflect the conditions that prevailed in the early Univers e. Analysis of the physical mechanisms by which these anisotropies for med shows how they may be used to constrain fundamental cosmological p arameters and provide insight into the origin of large-scale structure in the Universe.