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. |
