The Beginning of the Modern Universe
The Grand Unification Epoch took place from 10^-43 seconds to 10^-36 seconds after our universe was born. Quantum theory allows us to form a clearer picture of this Epoch compared to the mysterious Plank Epoch.
During the Grand Unification Epoch, the universe was still extremely hot and incomprehensibly small. However, it had cooled down enough to allow the force of gravity to separate from the other three fundamental forces. The unification of the strong nuclear, weak nuclear, and electromagnetic force that existed during this period of time is referred to as the electronuclear force. However, the splitting off of gravity from the electronuclear force wasn't the only milestone of this epoch- this is also when the first elementary particles began to form.
What Are Elementary Particles?
Elementary Particles are particles which have no substructure- i.e. they are the simplest form of matter possible. Elementary particles are the building blocks of electrons, neutrons, protons and more! Currently, there are 17 elementary particles that have been confirmed- the unconfirmed "gravitron"is still in the theoretical category. There are 12 "matter" elementary particles and 5 "force carrier" particles.
These are the matter elementary particles are what make up the physical part of subatomic particles and are referred to as fermions. The two categories of elementary fermions are quarks and leptons. Quarks combine to form particles known as Hadrons (more on that later), which make up the famous neutrons and protons; Leptons form electrons and other fundamental particles.
The 5 force carrier particles mediate the interactions between the weak magnetic, strong magnetic, and electromagnetic forces. Bosons are the fundamental reason for the attractions/reactions we view as forces.