| Time | Era | Temperature | Characteristics of the Universe |
| 0 to 10-43 s | Big Bang | infinite | infinitely small, infinitely dense Primeval fireball 1 force in nature - Supergravity |
| 10-43 s | Planck Time | 1032 K | Earliest known time that can be described by modern physics 2 forces in nature, gravity, GUT |
| 10-35 s | End of GUT | 1027 K | 3 forces in nature, gravity, strong nuclear, electroweak Quarks and leptons form (along with their anti-particles) |
| 10-35 to 10-33 s | Inflation | 1027 K | Size of the Universe drastically increased, by factor of 1030to 1040 |
| 10-12 s | End of unified forces | 1015 K | 4 forces in nature, protons and neutrons start forming from quarks |
| 10-7 s | Heavy Particle | 1014 K | proton, neutron production in full swing |
| 10-4 s | Light particle | 1012 K | electrons and positrons form |
| 100 s (a few minutes) |
Nucleosynthesis era | 109 - 107 K | helium, deuterium, and a few other elements form |
| 380,000 years | Recombination (Decoupling) | 3000 K | Matter and radiation seperate End of radiation domination, start of matter domination of the Universe |
| 500 million yrs | Galaxy formation | 10 K | galaxies and other large structures form in the universe |
| 14 billion years or so |
Now | 3 K | You are reading this table, that's what's happening. |