Small fluctuations in the CMB that reveal the seeds of cosmic structure.
The Sachs-Wolfe effect describes how gravitational redshift imprints temperature variations on the cosmic microwave background, revealing the seeds of cosmic structure. This article explains the effect, its role in cosmology, and the cosmic epochs it helps illuminate.
The dipole anisotropy is the largest temperature variation in the cosmic microwave background, a ~3.36 mK pattern caused by our motion relative to the CMB rest frame. It reveals the velocity of the Local Group and provides a crucial reference for cosmological measurements.
The Integrated Sachs-Wolfe (ISW) effect is a subtle imprint on the cosmic microwave background caused by the changing gravitational potentials of large-scale structure as photons travel through an accelerating universe. It provides a unique observational window into dark energy and the evolution of cosmic structure.
Hot and cold spots in the cosmic microwave background are tiny temperature variations—about one part in 100,000—that reveal the seeds of galaxies and the physics of the early universe. This guide explains their origin, how missions like COBE, WMAP, and Planck measured them, and why they matter for cosmology.
Acoustic peaks are periodic ripples in the cosmic microwave background temperature, imprinted by sound waves in the early universe. These peaks encode the fundamental physics of the Big Bang and have become a cornerstone of modern cosmology, revealing the composition and evolution of the cosmos.
