The History of the Universe

Age of Universe

Major Process

Summary

Unknown

The Laws of Physics break down at earlier times than this.

Unification of Forces

There is only one force – all the forces of nature are united as a 'super force'.

Inflation

Space expands very rapidly, becoming nearly flat.

Quark – Lepton era

Matter and antimatter are interacting all the time. There is slightly more matter than antimatter.

Hadron era

Protons and neutrons start to form

Helium synthesis

Some protons and neutrons combine to form helium nuclei. Matter and antimatter have reacted to leave a small surplus of matter.

Radiation era

The universe is opaque. Radiation and matter are in equilibrium, with all matter in a plasma. As a soon as an atom forms it is ionized.

Formation of atoms

The Universe is transparent to radiation. Atoms can form. The Universe is 75% hydrtogen and 25% helium with trace amounts of heavier elements.

Formation of stars and galaxies

Gravity forces clumping of matter to form stars and galaxies and larger structures.