A Brief History of the Universe
Time* Temp (GeV)** Temp (K)** Characteristics
10-43 s 1.2 x 1019 1.4 x 1032 Planck scale; quantum gravity; superstrings; spacetime foam?
10-35 s 1.0 x 1014 1.2 x 1027 Begin brief inflationary epoch; end of grand unified era
10-32 s 1.0 x 1014 1.2 x 1027 End of inflationary epoch; beginning of standard big bang evolution; origin of matter-antimatter asymmetry
10-11 s 1.0 x 102 1.2 x 1015 End of electromagnetic and weak force unification
10-6 s 1.0 1.2 x 1013 Confinement: quarks and gluons become bound in the hadrons
1 s 1.0 x 10-3 1.2 x 1010 Weak interactions drop out of thermal equilibrium (weak freeze-out)
~ 3 min 1.0 x 10-4 1.2 x 109 End nucleosynthesis of light elements
103 y 1.0 x 10-8 1.2 x 105 End of radiation dominance; begin matter dominance
105 y 3.0 x 10-10 3.6 x 103 Electrons and protons combine to form atoms; photons and matter decouple
109 y 8.0 x 10-13 ~ 10 The first galaxies have formed by now
~ 1010 y 2.3 x 10-13 ~ 3 The present Universe
*Since big bang   **Conversion: 1 GeV = 109 electron-Volts (eV) = 1.2 x 1013 kelvins (K)