Big Bang Theory: Modern universally acceptable principle regarding the origin of the universe is the ‘Big Bang Theory’. It is also called the Expanded Universe Hypothesis, because this principle states that the universe is continuously expanding. The credit for propounding this principle goes to Edwin Hubble, who, on the basis of the evidence, proved that the universe is expanding, and over time, the galaxies are moving away from each other. The scientists have found that the distance between the galaxies cannot increasing but the expansion of galaxies cannot be proved practically.
Stages of the expansion of the universe: According to the Big Bang theory,
The expansion of the universe has occurred in the following three stages:
1. Materials that created the universe being concentrated at one place: All the substances that created the universe were concentrated initially in the same place in the form of Singularity (Singular Atom) a tiny ball (singular atom). The volume of these subtle substances was almost zero and temperature and density was infinite.
2. The expansion of the universe at a rapid pace by the explosion process: According to the Big Bang theory, these small particles exploded at a rapid pace with the passage of time. The universe expanded at a rapid pace due to this explosion. This extension continues even today. The phenomenon of expansion happened at a very fast pace in the smallest part of a second. After this, the speed of expansion slowed down. The first atom was formed in the first three minutes of the beginning of Big Bang. This incident of explosion took place almost 14 billion years ago.
3. The rapid decrease in temperature: Due to the occurrence of the Big Bang phenomenon, rapid decrease in temperature took place during three million years. It fell to about 4200°C and the production of atomic substances resulted This led to the formation of a transparent universe.
In a nutshell, the galaxies in the universe were created by this process. Galaxies were small in the beginning. The distances between them were less. The tiny balls located in the middle of the galaxies due to the Big Bang process triggered the spread of the distance between the galaxies, i.e. the universe started expanding.
Thus the planets formed due to the explosion of stars and the condensation of matter. This process was repeated on planets and satellites were formed. Thus the solar system and the planets were formed.
Criticism:
The following criticisms have been made for this principle:
1. According to this principle, the distance between the galaxies is increasing but astronomical observation does not prove the expansion of galaxies.
2. The astronomer Hoyle has rendered the ‘steady state concept’, according to which, the universe has remained the same at any time. Although, there are so many evidences today on which basis the scholars are further studying the universe.
