“Primeval Atom,” or also known as “Big bang,” is a prominent theory, main candidate, and well-proven empirical answer for the ultimate question, “How did the universe begin?” The Big Bang Theory is a cosmological model of the observable universe from the earliest known periods through its subsequent large-scale evolution. The model describes how the universe expanded from an initial state of extremely high density and high temperature, in short: in a very tiny atom. For several decades, the scientific community was divided between supporters of the Big Bang and the rival steady-state model, but a wide range of empirical evidence has strongly favored the Big Bang, which is now universally accepted.