Origin of Earth - Civil Services Preparation Online! UPSC & IAS Study Material

Origin of Earth

by Devender

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There are various theories about how Earth and the Solar System came into existence. These theories came from scientists from all over the world stating different facts.

Origin of Earth

  • Gaseous Theory:
  • It was given by Imanuel Kant in 1755. He was German and he stated in his theory that primordial matter was evenly distributed in the shape of small & cold particles from which our earth & other planets of the solar system formed.

  • Nebular Hypothesis:
  • It was given by Laplace in 1796 who was French. According to him, primordial matter existed in form of intensely hot & rotating gaseous mass known as Nebula which cooled with time. It resulted in the decrease in Nebula's volume and increasing its rotational speed which increased its centrifugal force.

    When this centrifugal force exceeded the gravitational force, a ring shape deformed from the nebula & many other rings formed out of its breaking which later became planets and satellites, and the remaining part of Nebula is Sun.

  • Planesimal Hypothesis:
  • It was given in 1900 by Chamberlain & Moulton. It stated that a wandering star approached the Sun and exerted its gravitational pull on the Sun. As a result, a cigar-shaped material separated from Sun. When finally, the start moved away from the Sun, this material started revolving around the sun and later condensed, becoming planets.

  • Tidal Hypothesis:
  • It was given by Sir James Jeans (British) & Harold Jeffrey. They stated that Sun was a gaseous mass and another star bigger than Sun accidentally came close to Sun. The gravitational pull of the star pulled gaseous mass away from the sun forming a giant tongue of matter which formed the planets.

  • Big Bang Theory:
  • It was given by Edwin Hubble in 1929 and he was an American. He stated that everything emerged from a point which is known as Singularity and it happened around 13.7 billion years ago. When the galaxies moved away, the space between them expanded which is known as Red shift. As the universe expanded, hot radiation cooled down leading to the formation of different galaxies and further broke to starts which broke to form planets.


    Curved Surface of Earth

    Talking about a ships' visibility, when a ship appears over the distant horizon, the top of the mast is seen before the hull & vice versa.

    Even the Sun rises & sets at different times in different places. As the earth rotates from west to east, places in the east see the sun earlier than those in the west.

    During a Lunar eclipse, the shadow of Earth cast on the Moon is always circular proving it is curved not plain.

  • Driving poles on level ground on curved earth:
  • Engineers have conducted experiments by driving poles of equal length at regular intervals on the ground. They found out that poles do not give a perfect horizontal level, the center pole projects slightly above the poles at either end. This is because of the curvature of the Earth which is 8” to a mile.

  • Aerial Photographs:

The pictures taken from high altitudes or from space by rockets or satellites clearly show the curvature of Earth which is the best proof of the sphericity of Earth.



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