| Quantum gravity epoch | Grand Unification epoch | Quark epoch | Lepton epoch | Photon epoch | ||||
|
| Radiation-dominated era | Matter-dominated era | ||||||
| Plank era: Laws of physics unknown | Grand Unified Theory Epoch: matter dominates antimatter | Electroweak era: dominated by quarks and anti-quarks | Hadrons & leptons era: Quarks form protons, neutrons & baryons | Protons & neutrons combine to form hydrogen, helium, lithium & deuterium nuclei | Radiation era: strong coupling of matter & antimatter | Matter & energy decouple. Cosmos becomes transparent for CMB* | Stars, quasars, proto-galaxies form. Stars begin to breed heavy elements | |
| 10−43 secs 10−35 secs 10−10 secs 1 second 3 minutes 300,000 years 1 billion years | ||||||||