Time (s) T (Kelvin) Reference Event
CBR
1x10^-43 1x10^32 KT 72 Quantum limit of classical general
relativity
1x10^-38 1x10^29 KT 72 Limit of perturbative interaction
thermalization of universe
1x10^-35 1x10^28 KT 72 Grand unification spontaneous
symmetry breaking
1x10^-34 1x10^27 KT 274 Approximate start of inflation
1x10^-32 1x10^27 KT 274 Approximate start of reheating and
end of inflation
1x10^-11 3x10^15 KT 72 Electroweak unification spontaneous
symmetry breaking
2x10^-7 2x10^13 HA 353 Tauon anti-tauon annihilation
1x10^-5 2x10^12 KT 72 Formation of hadrons from quarks
7x10^-5 1x10^12 HA 353 Muon anti-muon annihilation
5x10^-4 4x10^11 KT 159, 281 By this time the universe has a
baryon-antibaryon asymmetry
which results from post-inflationary
B,C,CP violating processes
1x10^-1 3x10^10 BS Neutral current weak interactions
become too slow and neutrinos
decouple
1x10^0 1x10^10 BS Charged current weak interactions
become too slow and neutron to
proton ratio freezes out
1x10^1 5x10^9 BS Electron positron annihilation
1x10^2 1x10^9 BS Typical photon energies drop below
the deuteron binding energy and
nucleosynthesis begins
1x10^3 4x10^8 BS Particle energies drop below coulomb
barrier energies and nucleosynthesis
ends
4x10^10 6x10^4 KT 77 Matter density becomes equal to
radiation density
4x10^12 3.5x10^3 KT 78 Electrons and protons recombine into
hydrogen atoms
6x10^12 3.0x10^3 KT 80 Photon decoupling
2x10^16 20 HA 349 Formation of galaxies
(X-1.4x10^17) --- KT 12 Formation of the solar system
(X-9.9x10^16) --- HA 390 Emergence of life on Earth
X ~ 4.7x10^17 2.726 KT 12 Today
These values are rough estimates only. I have taken Omega_0=1, Lambda_0=0, and h=1.