16 out 199997983 ano antes da era comum - Photon Epoch

Descrição:

Photon Epoch (or Radiation Domination), from 3 minutes to 240,000 years:
During this long period of gradual cooling, the universe is filled with plasma, a hot, opaque soup of atomic nuclei and electrons. After most of the leptons and antileptons had annihilated each other at the end of the Lepton Epoch, the energy of the universe is dominated by photons, which continue to interact frequently with the charged protons, electrons and nuclei.