Origin of the Universe – UPSC Notes/PDF

A large number of hypothesis were put forth by the famous philosophers and scientists from time to time regarding the origin of the earth and universe. However, the only certain hypothesis was able to attract the world. Here are those popular hypotheses.

Nebular Hypothesis

  • It was given by German philosopher Immanuel Kant and later it was revised by Mathematician Laplace in 1796.
  • The argument was that the planets were formed out of a cloud of material associated with a youthful sun, which was slowly rotating.
  • Later, it was revised by Otto Schmidt in Russia and Carl Weizascar in Germany in 1950.
  • They considered that the sun was surrounded by solar nebula containing mostly the hydrogen and helium along with what may be termed as dust.
  • The friction and collision of particles led to the formation of a disk-shaped cloud and the planets were formed through the process of accretion.

Binary Theories

  • In1900, Chamberlain and Moulton considered that a wandering star approached the sun. As a result, a cigar-shaped extension of the material was separated from the solar surface. As the passing star moved away, the material separated from the solar surface continued to revolve around the sun and it slowly condensed into planets.
  • Sir James Jeans and later Sir Harold Jeffrey supported this argument.
  • At a later date, the arguments considered of a companion to the sun to have been coexisting.

All these were hypothesis regarding the origin of the earth only. Later scientists also tried to find out the reason behind the origin of the universe.

Big Bang Theory

  • It is also called Expanding Universe Hypothesis, given by Edwin Hubble in 1920.
  • The argument was that the universe is expanding.
  • In the beginning, all matter forming the universe existed in one place in the form of a “tiny ball” (singular atom) with an unimaginably small volume, infinite temperature and infinite density.
  • At the Big bang, the tiny ball exploded violently. this led to a huge expansion. It is now generally accepted that the event of big bang took place 13.7 billion years before the present. The expansion of the universe continues even to the present day.
  • Within 3 lakh years from the Big Bang, the temperature dropped to 4500 Kelvin and gave rise to atomic matter. The universe became transparent.

From the UPSC point of view, the important theory is Big Bang theory, other theories may be asked in prelims.