dec 7, 402855126 BC - Lepton Epoch
Description:
Lepton Epoch, from 1 second to 3 minutes:
After the majority (but not all) of hadrons and antihadrons annihilate each other at the end of the Hadron Epoch, leptons (such as electrons) and antileptons (such as positrons) dominate the mass of the universe. As electrons and positrons collide and annihilate each other, energy in the form of photons is freed up, and colliding photons in turn create more electron-positron pairs.
Added to timeline:
the big bang
The big bang theory timeline
Date:
