The interactive reference to the origin and evolution of the universe, covering core concepts and common inquiries.
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.
Primordial helium, forged in the first minutes after the Big Bang, provides a crucial test of the hot Big Bang model. Its measured abundance matches theoretical predictions, reinforcing our understanding of the universe’s origin and evolution.
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 Big Bang was not an explosion from a single point in space. It was the beginning of space and time itself, occurring everywhere in the universe simultaneously. This article explains the origin, key epochs, and evolution of the cosmos, from the Planck epoch to the present day, and why the universe has no center or edge.
The Big Bang is the leading scientific explanation for the origin of the universe, describing its expansion from an extremely hot, dense state 13.8 billion years ago. This article explores the evidence, the cosmic epochs that followed, and the open question of what triggered the initial event.
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 Big Bang theory is the leading scientific explanation for the origin and evolution of the universe. It describes how the cosmos emerged from an extraordinarily hot, dense state 13.8 billion years ago and has been expanding and cooling ever since — from the Planck epoch through inflation, nucleosynthesis, recombination, and the formation of stars and galaxies.
The cosmic microwave background is uniform to one part in 100,000, a puzzle solved by cosmic inflation. This article explains the CMB’s origin, the epochs of the early universe, and how missions like COBE, WMAP, and Planck have measured it.
