Light emitted from Hydrogen discharge tube - When a Hydrogen atom is excited by an external energy, the electrons will "jump" to a higher energy state and when the electron start to lose energy, it drops back to a lower energy state by releasing it's energy in the form of light.
Now, the universe is relatively cool enough not to cook up new quarks, so the remaining quarks quickly fused together to form a class of heavier particles called hadrons. Hadrons are heavier particles and they are the particles we find in every nucleus of an atom that made up all visible, normal matter. Protons and neutrons are members of the hadron family. At this time, though the universe is relatively cool but it still have the energy to spontaneously generate anti-hadrons and it will continue to annihilate with the hadrons until the universe is cool enough not to produce hadron and anti-hadron pairs. The asymmetry is still at work and the hadrons that survived the annihilation ultimately get to see the universe as they will form stars and planets and eventually us.
If the universe did not start out with the asymmetry the universe will have no particles left to survive because all would have been annihilated to produce photons.
By now, it has been one second after the Big Bang.
The size of the universe is now a few light years across, that is approximately the distance between our sun and its closest few stars. At a billion degrees, it is still hot enough to spontaneously produce electrons and anti-electrons. But, as the universe continues to expand and cool, eventually this process stops and again, there is an asymmetry between the electron and the positrons (anti-electrons) which cause some electrons to remain.
So, now we have protons, neutrons and electrons which are the primary ingredients to form any element of nature in the periodic table. As the universe continue to cool to about 100 million degrees, protons and neutrons start to stick together manufacturing the first atomic nuclei and born the universe which 90% composed of hydrogen and 10% of helium along with trace amounts of deuterium, tritium and lithium.
Two minutes has passed since the beginning.