The Grand Unification Epoch was a fleeting period in the early universe, from about 10⁻⁴³ to 10⁻³⁵ seconds after the Big Bang, when three of the four fundamental forces were unified. This article explores that epoch, its place in cosmic history, and the full timeline from Planck time to the present day.
Before recombination, the universe was an opaque plasma of free electrons and photons. When electrons and protons combined to form neutral hydrogen, light finally decoupled, creating the cosmic microwave background. This article explains the physics behind this cosmic milestone and why no telescope can see earlier with light.
A CMB map is a snapshot of the oldest light in the universe, revealing tiny temperature variations that seeded all cosmic structure. This guide explains what the map shows, the major epochs from the Planck era to reionization, and how missions like COBE, WMAP, and Planck turned the cosmic microwave background into a precision tool for cosmology.
Cosmological redshift is the stretching of light to longer wavelengths as the universe expands. This phenomenon underpins our understanding of cosmic history, from the Big Bang to the formation of galaxies, and is a cornerstone of modern cosmology.
The Big Bang is the leading scientific explanation for the origin of the universe, describing how it expanded from an extremely hot, dense state about 13.8 billion years ago. This comprehensive guide walks through the sequence of cosmic epochs—from the Planck epoch to the present day—covering the formation of particles, atoms, stars, and galaxies, and the evidence that supports this model.
Explore the Big Bang model, from the Planck epoch to the formation of stars and galaxies. Learn about cosmic inflation, the cosmic microwave background, and the evidence supporting our modern understanding of the universe’s origin.
The hadron epoch was a critical phase in the early universe when quarks first bound into protons and neutrons. This article explains its place in cosmic history, its key processes, and why it matters for understanding the matter we see today.
Big Bang nucleosynthesis (BBN) is the production of light elements during the first minutes of cosmic time. Its evidence comes from the remarkable agreement between predicted and observed primordial abundances, which also constrains the baryon density and supports the standard hot Big Bang model.
About three minutes after the Big Bang, the universe cooled to roughly a billion degrees, allowing protons and neutrons to fuse into light nuclei. This process, known as Big Bang nucleosynthesis, fixed the primordial hydrogen-to-helium ratio that still dominates the cosmos today.
In the late 1990s, two independent teams used Type Ia supernovae as standard candles to trace the universe’s expansion history. Their surprising conclusion—that cosmic expansion is accelerating—revolutionized cosmology and led to the concept of dark energy, a mysterious force driving the universe apart.
