Early Theories of the Earth| Class 11 Geography Notes

Early Theories of the Earth: The Earth and other planets in our solar system formed due to the pull of gravity. About 4.63 billion years ago, the solar system was a cloud of gas and dust called a “Nebula.” In this discussion, we’ll explore early theories about Earth’s origin, including Kant’s “Gaseous Hypothesis”, Laplace’s “Nebular Hypothesis” and also Chamberlin’s “Planetesimal Hypothesis” in this article. These notes are specially curated by an expert team at GeeksforGeeks for all the students for their better understanding and to help them in their examinations.

Early Theories of the Earth

Early theories of the Earth’s origin explore how our planet formed. Researchers proposed various theories to explain this process. Seven famous theories include Kant’s “Gaseous Hypothesis,” Jean and Jeffery’s “Tidal or Gravitational Theory,” Laplace’s “Nebular Hypothesis,” Hoyle’s “Supernova Hypothesis,” Schmidt’s “Interstellar Hypothesis,” Chamberlin’s “Planetesimal Hypothesis,” and another one of Hoyle’s “Supernova Hypothesis.”

These theories offered foundational ideas about Earth’s beginnings but also faced criticism. According to them, after gravity caused matter to collapse, it began to spin. The centre of this spinning matter became the sun, with other matter forming planets, moons, meteors, and other celestial bodies. Particles bound by gravity moved in specific directions, forming orbits around these heavenly bodies.

Kant’s Gaseous Hypothesis

• Immanuel Kant, a German philosopher, proposed his theory of Earth’s origin in 1755.
• Kant’s theory was heavily influenced by Newton’s Law of Gravity.
• According to Kant, substances initially spread out in space were made of cold, unmoving solid particles. These particles collided due to gravity’s pull, generating heat and angular momentum, causing them to start spinning.
• This spinning led to the formation of a hot nebula, which rotated around a central object, creating strong centrifugal force that formed rings of matter.
• As these rings cooled, they formed planets and satellites.
• However, Kant’s hypothesis faced criticism for not explaining the source of energy that caused the motion of these celestial bodies.

Laplace’s Nebular Hypothesis

• The renowned mathematician Laplace revised Kant’s theory in 1976 with his Nebular Hypothesis.
• Laplace proposed that a solar nebula, primarily composed of hydrogen, helium, and dust, surrounded the sun.
• He suggested that the formation of disk-shaped clouds occurred due to the impact and friction of celestial particles.
• According to Laplace, the planets formed in association with the newly formed star, the sun, through a process of accretion of these celestial particles.
• However, Laplace’s hypothesis faced criticism as it did not explain the origin of the nebula itself.
• Additionally, it couldn’t determine the source of the nebula or the primary source of its heat and motion.

Chamberlin’s Planetesimal Hypothesis

• The Planetesimal Hypothesis of Chamberlin, also known as the Binary Theory, was proposed by Chamberlin and Moulton in 1900.
• According to this theory, another wandering star collided with the sun. As a result of this collision, a cigar-shaped extension formed from the celestial material, and the surface of the sun separated from this extension.
• The sun emitted hot material called “Prominences,” which were very high in temperature.
• The particles from these materials began to spin and coalesce, forming the planets.
• This process generated a significant amount of heat.
• As the separated materials cooled down, they started to condense and form the planets.
• The passing star then moved away, and the sun continued to spin on its own axis.
• However, the Binary Theory fails to explain why only nine planets were formed during the collision of these stars.

Conclusion

In this article on early theories about Earth’s origin, we explored the formation of the solar system and its planets, along with other celestial bodies. We delved into Kant’s “Gaseous Hypothesis” and Laplace’s “Nebular Hypothesis” as well as Chamberlin’s “Planetesimal Hypothesis” including criticisms of each theory.

Early Theories of the Earth- FAQs

What is the Nebular Hypothesis? 

According to this theory, the solar system arrived at its current form after collapsing from a molecular gas cloud some 4.568 billion years ago.

What is the Theory of Biogenesis?

The theory of biogenesis states that life has evolved from pre-existing life forms.

What is the Theory of Abiogenesis?

Theory of abiogenesis states that life originated abiogenetically (suddenly and spontaneously) from any kind of non-living matter like mud, dust, etc.

What are the 7 famous Early Theories of the Earth?

Seven famous theories include Kant’s “Gaseous Hypothesis,” Jean and Jeffery’s “Tidal or Gravitational Theory,” Laplace’s “Nebular Hypothesis,” Hoyle’s “Supernova Hypothesis,” Schmidt’s “Interstellar Hypothesis,” Chamberlin’s “Planetesimal Hypothesis,” and another one of Hoyle’s “Supernova Hypothesis.”‘

What is one theory on how early Earth was formed?

Scientists believe that Earth, like the other inner planets, came to its current state in three different stages. The first stage, described above, is known as accretion, or the formation of a planet from the existing particles within the solar system as they collided with each other to form larger and larger bodies.