Big Bang Theory of Earth Origin | Notes |10 Key Points

Big Bang Theory is  the most popular theory of  Origin of Earth. About 13.7 billion year ago, all matter forming the universe was in a singular Tiny ball like structure which was even smaller then the size of Atom with infinite temperature and density.  you should note that it is a theory, not a hypothesis because it have two evidences.   

  1. Results from Hubble Telescope
  2. Cosmic Background Radiation
 According to this theory – 

1. Whole Universe was made from Singularity.

2. Singularity – A tiny ball like structure, smaller then an atom with infinite temperature and density.

3. About 13.7 billion year ago, That tiny ball exploded and led to the formation of the universe.

4. With Explosion, Universe started to expand ( rapid expansion at start, then slowed down).

5. After Explosion, Universe started to cool down, cooling of energy led to the formation of sub-atoms like electrons, protons, neutrons and photon.

6. After thousand of years of explosion, these sub-atom started to fuse with each other  and formed atomic particles like hydrogen and helium. As time passed other elements are also came into existence.

7. When there was no fusion bw particles no heat and light was there, thatswhy the universe was dark and considered as opaque, but soon after fusion started heat and light started to generate and universe  became transparent.

8. Now gases likes Hydrogen and Helium started to get collected in a cloud like structure called Nebula.

9. Lumps started to form in the Nebula which led to the formation of the star and planets. as we saw in Nebular Hypothesis. 

10. Our Solar system was made some 5-5.6 billion year ago and planets formed 4.6 billion year ago.


Rate of expansion of universe is not decreasing but increasing.

It was assumed that matter formed in the  universe will slow the rate of expansion as

Mass create gravity–Gravity creates Pull–with pull the expansion should get slowed down.

but, It is accelerating as shown by the supernova observation . something extraordinary is pushing the galaxies away- which we call as Dark Energy.

Even scientist doesn’t know what this energy is.

Proofs of Big Bang Theory

Expanding Galaxies- in 1929 Hubble found that galaxies are moving away from each other, that means universe is Expanding and scientist assumed that it all should has been started from a point.

Cosmic Background Radiation – the radiation emitted from the big bang explosion is still found today in the space various programs like COBE and WAMP are trying to analyse to find the exact origin of universe .

About Rohit Chaudhary

Graduate, helping others to graduate

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