In this Electroweak Era, the weak force separates into its own unique interaction so that all four fundamental forces are now in place: gravity, the strong nuclear, weak nuclear and electromagnetic forces. The fact that these four forces are now independent lays the foundation for everything we now know about physics.

The universe is still too hot (too full of energy) for any physical matter to exist. But bosons — the subatomic W, Z and Higgs particles — have emerged as “carriers” for the fundamental forces.