Redshift is the stretching of light to longer wavelengths as the universe expands, measured by comparing observed spectral lines to their known rest wavelengths. This article explains the methods, instruments, and cosmic epochs revealed by redshift, from the Planck epoch to the present day.
The Sunyaev-Zel’dovich (SZ) effect is a subtle distortion of the cosmic microwave background caused by hot gas in galaxy clusters. It offers a powerful way to detect clusters, probe the large-scale structure of the universe, and measure cosmological parameters like the Hubble constant.
The cosmic microwave background (CMB) is the most perfect blackbody ever measured, with a spectrum matching a 2.725 K Planck curve to better than one part in 10,000. This article explains how the CMB achieved this perfection, why it persists, and what it reveals about the universe from the Planck epoch to the present day.
The odd acoustic peaks in the cosmic microwave background power spectrum are higher than even peaks because of adiabatic initial conditions and baryon loading. This article explains the physics behind these peaks and traces the evolution of the universe from the Planck epoch to structure formation.
The first supernovae—explosions of massive Population III stars—scattered heavy elements across the early cosmos, shaping the formation of the first galaxies. This article explains the process, the cosmic epochs involved, and the evidence from simulations and observations.
The Eddington limit sets a theoretical maximum on how fast a black hole can accrete matter, balancing radiation pressure against gravity. Yet super-Eddington accretion may explain how supermassive black holes grew so quickly in the early universe, a puzzle sharpened by JWST observations.
Baryogenesis is the process that generated the observed imbalance between matter and antimatter in the early universe. This article explains the Sakharov conditions, leading scenarios such as electroweak baryogenesis and leptogenesis, and traces the cosmic epochs from the Planck era to recombination.
Primordial black holes are hypothetical black holes that formed in the first moments after the Big Bang, before stars and galaxies existed. They could explain dark matter and offer a unique window into the universe’s earliest epochs, from the Planck era to recombination.
Redshift surveys map the three-dimensional distribution of galaxies by measuring their redshifts, revealing the large-scale structure of the cosmos and providing critical evidence for dark matter, dark energy, and the sequence of cosmic epochs from the Big Bang to the present.
The BICEP/Keck experiment is a series of South Pole telescopes searching for the faint polarization pattern in the cosmic microwave background that would signal primordial gravitational waves from cosmic inflation. While no direct detection has been made as of 2025, the experiment has set the tightest constraints yet on inflation models.
