The interactive reference to the beginning and evolution of the universe.
The first stars emerged roughly 100–200 million years after the Big Bang, ending the cosmic dark ages. This article traces the full evolution of the universe—from the Planck epoch through inflation, recombination, and reionization—and explains how the first atoms, stars, and galaxies formed, with key evidence from COBE, WMAP, Planck, and JWST.
Population III stars are the hypothetical first generation of stars, formed from primordial hydrogen and helium. They were likely massive, hot, and short-lived, and their radiation reionized the early universe. This article explores their formation, properties, and cosmic significance.
The photon epoch was a period in the early universe, from about 10 seconds to 380,000 years after the Big Bang, when photons dominated the energy density. During this time, atomic nuclei formed via nucleosynthesis, and the universe remained a hot, dense plasma until recombination produced the cosmic microwave background.
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.
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.
Explore the question of whether time began with the Big Bang, and journey through the major cosmic epochs—from the Planck epoch to the formation of stars and galaxies—guided by the standard Lambda-CDM model of cosmology.
The cosmic microwave background (CMB) is the oldest light in the universe, a relic of the hot Big Bang. This article explains how astronomers measure it from Earth, what it reveals about cosmic history, and why it anchors our modern understanding of the cosmos.
