Nobel Lecture: Cosmic microwave background radiation anisotropies: Their discovery and utilization*

Observations of the cosmic microwave background CMB temperature anisotropies have revolutionized and continue to revolutionize our understanding of the universe. The observation of the CMB anisotropies angular power spectrum with its plateau, acoustic peaks, and high frequency damping tail have established a standard cosmological model consisting of a flat critical density geometry, with contents being mainly dark energy and dark matter and a small amount of ordinary matter. In this successful model the dark and ordinary matter formed its structure through gravitational instability acting on the quantum fluctuations generated during the very early inflationary epoch. Current and future observations will test this model and determine its key cosmological parameters with spectacular precision and confidence.