Origin of Universe : The Big Bang

Our Universe

Universe

Universe is a popular but word but a undefined thing. Exploration is very far, human can not even see the whole universe. Universe is infinite but everything has an origin and so does universe. 

Origin of universe 

Origin of universe (The big bang)

The origin of universe is the most fundamental question for the mankind. It is also the most debatable topic. Scientists are not unanimous on this topic. There are many theories which tries to explain it like :

• The Big Bang 
• Time's arrow
• The nows have it 
• Religious theories

Apart from it there are also many theories which are not much popular. In our first blog series "Origin of universe" we are going to discuss them one by one. 
Today , we are going to discuss the one of the most believed theory about the origin of universe , The Big Bang theory

The Big Bang Theory :

What is the Big Bang ?

 Since early part of the 1900s, one explanation of the origin and fate of the universe, the Big Bang theory, has dominated the discussion. Proponents of the Big Bang maintain that, between 13 billion and 15 billion years ago, all the matter and energy in the known cosmos was crammed into a tiny, compact point. In fact, according to this theory, matter and energy back then were the same thing, and it was impossible to distinguish one from the other.

Adherents of the Big Bang believe that this small but incredibly dense point of primitive matter/energy exploded.
According to this theory , the universe is expanding since the start of time as it is believed that time started when big bang happened. 

This hypothetical starting point of everything was an infinite concentration of energy referred to as a singularity.

The Big Bang

How it came into existence ?

The  Big Bang theory came into existence by the observation that the galaxies moving far from each other.

It  this believed that Universe is expanding its radius with greater velocity than that of light (c).

Galaxies moving apart (The big bang )
Image credit : technologyvista.com

But some galaxies like Milky Way and Andromeda are coming near and will collide in future. If you want to know the reason click here.

Within seconds the fireball ejected matter/energy at velocities approaching the speed of light. At some later time—maybe seconds later, maybe years later—energy and matter began to split apart and become separate entities. All of the different elements in the universe today developed from what spewed out of this original explosion.

Big Bang theorists claim that all of the galaxies, stars, and planets still retain the explosive motion of the moment of creation and are moving away from each other at great speed. This supposition came from an unusual finding about our neighboring galaxies. In 1929 astronomer Edwin Hubble, working at the Mount Wilson Observatory in California, announced that all of the galaxies he had observed were receding from us, and from each other, at speeds of up to several thousand miles per second.

What happened after Big Bang ?

It is believed that the singularity blasted in the form of energy and then it transformed in matter and then the atoms formed.

How the atoms formed ?

One second after the big bang ,the matter started to form proton and neutrons. 

And within three minutes , the protons and neutrons started forming Hydrogen and helium. 

Hydrogen was 75 % while Helium was 25 % by mass.

H & He ( The Big Bang )

What happened after atoms formed?

It is believed that first Hydrogen and Helium were formed and then these hydrogen and helium combined to form stars due to interaction due to gravity. But we know that gravity is not a effective force between atomic particles and atoms are neutral so electrostatic force was absent. As a result of which , it took a long time to for formation of first star by accumulation of clouds of Hydrogen and Helium.

Supercomputer simulation of formation of star ( The Big Bang )
Image credit : Space Answers

After it neutron star , pulsars and Hydrogen stars start forming

How long did it took for formation of first star ?

It took about 180 million years after the formation of first star according to researchers. 

History of the theory

English astronomer Fred Hoyle is credited with coining the term "Big Bang" during a talk for a March 1949 BBC Radio broadcast, saying: "These theories were based on the hypothesis that all the matter in the universe was created in one big bang at a particular time in the remote past."

Development of Big Bang Theory

The Big Bang theory developed from observations of the structure of the universe and from theoretical considerations.

One of the greatest scientists of all time Albert Einstein said , " For every one billion particle of matter there were one billion and one particle of matter and during the mutual annihilation one particle of matter remained and that is our universe ". Albert Einstein quoted it about the big bang theory because it is believed that annihilation took place during the formation of universe between matter and antimatter .

The whole happenings of the universe can be understood by the cosmic calender.

In cosmic calender, the estimated age of universe (13.8 billion years) is assumed to be a year.

This can be understood by the following image :

Cosmic calender ( The big bang )
(Image credit : Wikipedia)

Conclusion :

The big bang theory is the most believed theory about the origin of universe. It describes that how universe originated from the singularity. It describes how stars are formed and still forming. All the prospects of this theory.
It can be summarized as :

• The singularity bursted in energy and matter and Big Bang happened. 
• It cooled down and formed protons and neutrons. 
• They formed atoms. First atoms of Hydrogen and Helium were formed. 
• They accumulated in clouds and formed stars. First star was formed 180 million years after Big bang.
• Edwin Hubble's observation stated that Universe is expanding its radius greater than speed of light. 

Opinion :

• Mine : I think Big Bang is real theory because everything originates from singularity and i think so does universe.
• Your : You can give your opinion in comment section and also answer this  :

What do you think about The Big Bang ?

Comment your answer.

Bye !
In next part we will talk about other scientific theories