Chronology of the universe

Diagram of evolution of the (observable part) of the universe from the Big Bang (left) - to the present.

The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. The metric expansion of space is estimated to have begun 13.8 billion years ago. For the purposes of this summary, it is convenient to divide the chronology of the universe into four parts:

1. The very early universe, from the Planck epoch until the cosmic inflation or the first picosecond of cosmic time; this period is the domain of active theoretical research, currently beyond the grasp of most experiments in particle physics.
2. The early universe, from the Quark epoch to the end of the Photon epoch, or the first 380,000 years of cosmic time, when the familiar forces and elementary particles have emerged but the universe remains in the state of a plasma, followed by the Dark Ages, from 380,000 years to about 150 million years during which the universe was transparent but no large-scale structures had yet formed.
3. The period of large-scale structure formation including stellar evolution, galaxy formation and evolution and the formation of galaxy clusters and superclusters, from about 150 million years to present and prospectively until about 100 billion years of cosmic time. The thin disk of our galaxy began to form at about 5 billion years. The solar system formed at about 4.6 billion years ago with the earliest traces of life on Earth emerging by about 3.5 billion years ago.
4. The far future, after cessation of stellar formation, with various scenarios for the ultimate fate of the universe.