Origin of the Solar System

Scientists and philosophers all over the Earth from time to time, on unravelling the mystery of the Origin and evolution of our Solar system in general and our Earth in particular propounded various theories, hypotheses and concepts. Apparently, there is no consensus among the scientists about the origin of solar system and our Earth. Nevertheless, they safely concluded that the Earth would have been formed by the same process as the Solar system.

Historical Background

In earlier days, religious believes were prevailed to reason out the origin of Solar System. Notably, Archbishop Usher, the Prussian priest opined that the Earth was created on 26th October, 4004 B.C. at 9.00 AM (presumably Greenwich Mean Time) and this view has been quoted as mere fantasy since there is no supporting evidences submitted for his statement.

Due to the fact that the religious concepts lack logical and scientific basis & evidences, they were neglected by the modern scientific community. To solve this highly ambiguous riddle, numerous scientists came up with their own ideas, out of which Kant's Gaseous hypothesis served as the pioneer concept among others.

Theories of Origin of Solar System

Following are the major theories that define the origin of solar system:

Gaseous Hypothesis of Immanuel Kant

In 1755, Immanuel Kant, a German philosopher presented his hypothesis based on Newton's Gravitational law and rotatory motion.

According to Kant, due to the gravitational attraction, the primordial particles began to collide against each other, creating random rotatory motion which gradually became hot rotating nebula. Due to repeated collision, this resulted in the formation of nine irregular concentric rings from the core of the nebula. The residual central mass of the nebula remained as the Sun. The development of cores due to the irregularity of the rings, led to the formation of the respective planets and their satellites based on the condensation of materials.

Merits

• He put forward the first scientific theory on the Origin of our Solar system based on gravity and motion.

Demerits

• The source of origin of the primordial matter remains untold.

• This theory violates Newton's first law of motion.

• The reason behind the formation of the exact nine planets lacks any scientific base.

Laplace Nebular Hypothesis Theory

Pierre Simon de Laplace, a French mathematician, in 1796 he attempted to revise Kant’s Gaseous hypothesis. According to this hypothesis a slowing rotating hot cloud or nebula slowly turned into our present Solar System. On due course of time nebula cooled and began to shrink. As a result, the nebula rotated more rapidly flattened into proto-planetary disk. Later it became the Solar System due to the condensation of the rings into planets and their satellites and the residual part remained as the Sun.

Merits	Demerits
This hypothesis sounds very simple and logical	On citing flaws such as mismatching rotational speed of the Sun and condensation of the rings into planets the theory became unsatisfactory and planetesimal hypothesis started to gain momentum

Chamberlin’s Planetesimal Hypothesis

Thomas Chamberlin and Forest Moulton in 1905 proposed this hypothesis. They opined that the planets in the Solar System have formed as a result of collision between the sun and an approaching star due to gravity. This resulted in the shredding of a series of cigar shaped bolts i.e., planetesimal from the Sun’s surface. The bolts ejected from the Sun’s near side were thrown away over a long distance as Gaseous planets, while the others from the far side of Sun are ejected to lesser distance as terrestrial planets. The planets started to revolve around the Sun due to gravity.

Merits

This theory has introduced the concept of cigar shape.

This theory explains why the orbits of the terrestrial planets are highly elliptical whereas the gaseous planets are nearly circular.

Demerits

The theory did not explain the occurrence of the approaching star. The alignment of the sun and the approaching star appears to be incorrect.

Tidal Theory

Sir James Jeans theory

Sir James Jeans, a British scientist proposed the tidal hypothesis in 1919. Primitive stationery sun is approached by a bigger intruding star, causes the ejection of hot gaseous mass into cigar shaped filament due to the tidal pull of the intruding star. The filament is bulged in the middle and gets narrower towards its ends. Over a period of time, the hot gaseous mass condenses into bigger planets in the middle and smaller planets towards its ends combines to form nine planets of our Solar System. Gravitational pull of the sun and the tidal influence on the newly created planets results in the development of satellites.

Criticism: Origin of the intruding star that triggered the formation of filament was not explained. According to B Levin the stars are unlikely to encounter each other at such close quarters. The actual distance between the sun and the planets not mentioned.

Harold Jeffrey theory

Harold Jeffrey, a British physicist modified James Jeans’ Tidal Hypothesis and presented his concept as Collision hypothesis. According to his hypothesis there were three stars in the universe namely our primitive sun, partner star and intruding star. When the intruding star got collided with the partner star, the later was smashed into pieces and were scattered in the space and started revolving around the primitive sun which later formed into planets. The intruding star escaped the gravitational pull of the sun and faded away into space.

Criticism

The source of the existence of the early three stars was not reasoned out.

Collision Hypothesis by Buffon:

Georges de Buffon, a French scientist proposed the collision hypothesis in 1745. Due to the gravitational pull of the sun a comet which came very close to it undergone collision, lot of material got shredded away from the sun and condensed into planets (bigger mass) and asteroids (smaller mass).

Merits

He theorized the very first scientific hypothesis on the origin of solar system. The presence of the hot core of the earth supports this theory.

Demerits

As far as the size of the comets are concerned the collision cannot for such large planets in the solar system. This hypothesis fails to explain the cigar arrangements of the planets.

Russell’s Binary Star Hypothesis

H. N. Russell, an American astronomer propounded the Binary Star Hypothesis in 1937. According to him, there were two stars namely companion star which was revolving around the sun and approaching star which was far away from the sun. Approaching star which was revolving in the opposite direction to that of companion passes by each other. Due to the massive tidal pull of the approaching star, large amount of matter got attracted towards it from the companion star. Later on, planets were formed from the ejected matter and started revolving around the sun.

Demerits

Three such huge celestial objects must have been collided due to their strong gravitational pull. The fate of the companion star has gone unnoticed.

Hoyle’s supernova Hypothesis

This hypothesis was put forth by Fred Hoyle in 1946. The former twin of the Sun which got exploded due to nuclear fusion got converted into supernova. The supernova retains its position due to the gravitational effects of sun. When the supernova got exploded it was broken down into pieces scattered along large distance in the space. Those broken pieces were held together by the gravitational pull of the sun. They accreted to form planets and their satellites and started revolving around the sun.

Demerit

Origin of the former twin of the sun is unknown. The theory failed to address the cigar shaped positioning of the planet.

Schmidt’s Interstellar Dust Hypothesis

Otto Schmidt, a Russian scientist proposed this Interstellar Dust Hypothesis in 1943. Schmidt assumed that the interstellar space is filled with dust particles, which might have been formed from the matter coming out of star and meteors. They were unstable and not arranged in orderly manner started revolving around the sun as a flat disc. Over the time they started accumulating and condensed into form planets.

Demerits − The positioning of the planets lack cigar shape.

Big Bang Theory

Big bang model was initially proposed by a Russian mathematician Aleksandr Friedmann and Belgian astronomer George Lemaitre in 1920’s and the modern version was put forth by the American physicist George Gamow in 1940. It states that 13.79 billion years ago an explosion occurred rapidly from a highly compressed primordial state which had infinite density and temperature. Soon after the explosion, the universe began to cool down rapidly that allowed the formation of certain nuclei such as Hydrogen, Helium and Lithium. These elements then condensed through gravity that formed early stars and galaxies.

Merits

The cosmic microwave background radiation which is one of the remnants of the early universe have been observed in the recent scientific research.

Demerits

This theory violates the first law of thermodynamics which states ‘energy can neither be created nor be destroyed’.

Conclusion

The recent scientific advancements lead to the discovery of James Webb Telescope, that gives a broader understanding of the universe. However, the scope of space exploration is as big as the space itself.

Frequently Asked Questions

What is Solar System?

The Sun together with the group of celestial bodies that are held by its gravitational attraction revolve around it is called as The Solar System.

Who proposed the Gaseous Hypothesis model on the origin of our Solar System?

In 1755, Immanuel Kant, a German philosopher presented Gaseous hypothesis based on Newton's Gravitational law and rotatory motion.

Explain Collision Hypothesis of Buffon.

According to Buffon, due to the gravitational pull of the sun a comet which came very close to it undergone collision, lot of material got shredded away from the sun and condensed into planets (bigger mass) and asteroids (smaller mass).