Part IV: CMB Physics

The Cosmic Microwave Background

The cosmic microwave background (CMB) is the thermal radiation relic from the epoch of recombination at z ≈ 1100. Its near-perfect blackbody spectrum at T = 2.7255 K and tiny temperature anisotropies (ΔT/T ~ 10⁻⁵) encode a wealth of information about the geometry, composition, and initial conditions of the universe. The angular power spectrum of CMB fluctuations, with its characteristic acoustic peaks, provides precision measurements of cosmological parameters.

2.7255 K

CMB Temperature

~10⁻⁵

ΔT/T Anisotropy

ℓ ≈ 220

First Acoustic Peak

Topics in This Part

1. CMB Physics

Temperature anisotropies, acoustic oscillations, angular power spectrum, polarization (E and B modes), and Planck mission results

← Part IIICMB Physics →