The interactive reference to the beginning and evolution of the universe.
From the Planck epoch’s unimaginable heat to the cool darkness of the cosmic microwave background, the early universe underwent a dramatic cooling as it expanded. This guide traces the temperature milestones that shaped matter, light, and structure.
The universe was not infinitely small at the Big Bang. Cosmic inflation stretched space to a finite, macroscopic size before the hot Big Bang began. This article traces the universe’s evolution from the Planck epoch to today, explaining key epochs, the cosmic microwave background, and the formation of structure.
The universe is 13.8 billion years old. This definitive guide explains how astronomers measure the age of the cosmos using the cosmic microwave background, stellar evolution, and the expansion rate, and traces the universe’s evolution from the Planck epoch to the present day.
The lepton epoch was a brief but pivotal period roughly 1–10 seconds after the Big Bang, when electrons, positrons, and neutrinos dominated the universe. It set the stage for neutrino decoupling, the annihilation of electron-positron pairs, and the primordial conditions that led to Big Bang nucleosynthesis.
One second after the Big Bang, the universe had expanded and cooled enough for neutrinos to decouple, ending the quark–hadron transition and setting the stage for nucleosynthesis. This article traces the entire cosmic timeline from the Planck epoch to structure formation, explaining inflation, recombination, the cosmic microwave background, and the emergence of stars and galaxies.
Approximately 380,000 years after the Big Bang, the universe cooled enough for electrons and protons to combine into neutral hydrogen, releasing the cosmic microwave background. This pivotal moment, called recombination, marked the universe’s transition from an opaque plasma to a transparent state, setting the stage for the first stars and galaxies.
The first galaxies formed a few hundred million years after the Big Bang, ending the cosmic dark ages. Learn about the epochs of the early universe, the role of dark matter, the first stars, and how telescopes like JWST are rewriting our understanding of cosmic dawn.
The Big Bang timeline traces the universe from the Planck epoch through inflation, the first atoms, the cosmic microwave background, the dark ages, reionization, and the formation of galaxies. This guide explains the key epochs, the evidence from missions like COBE, WMAP, Planck, and JWST, and how the Lambda-CDM model ties the story together.
Galaxies formed from tiny quantum fluctuations in the early universe, growing through gravitational attraction and merging over billions of years. This guide explains the cosmic epochs from the Planck era to the present, the role of dark matter, and the evidence from the cosmic microwave background.
