Universe (The Big Bang Theory) | Geography

It is said that, initially there was a infinite small point with infinite temperature and infinite density and unimaginably small volume.

13.7 Billion year from present, The Big Bang happened which was an explosion leading to continuous expansion. Within the 1st three minutes of The Big Bang, the 1st set of particles and atoms began started forming.

Particle : A particle is the building block of everything we see around us. There are sub-atomic particle and atomic particle. Particles that are smaller than atom are sub atomic particle and smallest particle that can exist on its own in a natural state either by joining by other of its kind is atomic particle for example O₂ or H₂.

When Big Bang happened, 1st atomic particle formed was Hydrogen and hence Universe has more than 99.9% of its total matter as hydrogen. Hydrogen was the 1st atom to be formed and more than 99.9% of Universe exist in form of Hydrogen.

How a new atom can be formed?
It would require a Nuclear Level Reaction. Basically there are two Nuclear Reaction (1) Fusion (2) Fission

• Fusion : Fusion means joining i.e joining two atom we will get a bigger atom. Fusion reaction require very high temperature.                                                                                          Hydrogen has mass = 1 and atomic number = 1 and Helium has mass = 4 , that means Helium is 4 times heavier than Hydrogen. So to create Helium, we would require to fuse 4 Hydrogen atom. Also called Thermonuclear Reaction, which can create higher elements for which it require very high temperature i.e (10^⁷ celsius). Hence such reactions are possibles in stars.

• Fission : Fission means to separate i.e it is a nuclear reaction in which the nucleus of an atom splits into smaller parts.

Formation of Microwave radiation was next in the sequence that was released or formed in the first four hundred thousand years. This microwave radiation formed almost in the beginning of When Universe has expanded the maximum.

After this, we had a Phase of Darkness for few 100 million years and then came the Phase of Ultraviolet radiation. 

This was followed in the very 1st one billion year of the Big Bang by Formation of Stars and Galaxies.