Discuss two widely accepted theories of origin of the earth. Elucidate the position of all planets within the solar system and write the important facts of the earth. [ UPSC PYQ 2024 ]
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The two widely accepted theories of origin of the earth are:
Nebular hypothesis
The earth formed from a cloud of gas and dust, which collapsed under gravity, with the sun forming as it’s center.
Planetesimal hypotheses
The earth formed from the accumulation of small Rocky bodies called planetesimal, which merged to form larger bodies, eventually becoming the earth.
Position of earth within the solar system
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
The earth is the third planet the sun
Theories of Earth’s origin including Nebular Hypothesis and Protoplanetary Disk Model suggest gravitational collapse and accretion formed our planet. Understanding these theories provides insights into Earth’s formation, evolution and unique features.
The eight planets in our Solar System orbit the Sun in this order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Understanding their positions helps explain climate, asteroid belts, comets, eclipses and planetary movements. This knowledge aids space exploration, astronomical predictions and insights into the Solar System’s evolution.
Earth, our home planet is 4.54 billion years old with a diameter of 12,742 km. It rotates every 24 hours and orbits the Sun every 365.25 days. Composed of 71% water and 29% land, Earth’s atmosphere supports diverse life forms, making it unique in our Solar System.
The origin of the Earth has been a topic of much debate and speculation among scientists for centuries. Two widely accepted theories that attempt to explain the origin of our planet are the Nebular Hypothesis and the Giant Impact Hypothesis.The solar system is a vast and fascinating place, with each planet having its own unique characteristics. Earth, our home planet, is a special place that supports a wide range of life forms and ecosystems.
Nebular Hypothesis
Proposed By: Immanuel Kant (1755) and further developed by Pierre-Simon Laplace (1796).
Main Idea:
The Solar System formed from a large, rotating cloud of gas and dust called the solar nebula.
The nebula collapsed under gravity, causing it to spin faster and flatten into a disk.
The Sun formed at the center, and planetesimals coalesced from material in the disk to form planets.
Key Features:
Explains the orderly rotation and revolution of planets.
Accounts for the compositional differences between inner (terrestrial) and outer (gas giants) planets.
Criticism:
Fails to explain the observed angular momentum distribution in the Solar System.
Planetesimal Hypothesis
Proposed By: Thomas C. Chamberlin and Forest R. Moulton (1904).
Main Idea:
Planets formed from small, solid particles called planetesimals.
A nearby star’s gravitational pull caused material from the Sun to condense into planetesimals.
These planetesimals collided and coalesced to form planets.
Key Features:
Emphasizes the role of gravitational attraction and collision in planetary formation.
Supported by evidence of asteroid and meteorite composition.
Criticism:
Relies on a nearby stellar encounter, which is statistically improbable.
The origin of the Earth has been a topic of much debate and speculation among scientists for centuries. Two widely accepted theories that attempt to explain the origin of our planet are the Nebular Hypothesis and the Giant Impact Hypothesis.The solar system is a vast and fascinating place, with each planet having its own unique characteristics. Earth, our home planet, is a special place that supports a wide range of life forms and ecosystems.
Nebular Hypothesis
Proposed By: Immanuel Kant (1755) and further developed by Pierre-Simon Laplace (1796).
Main Idea:
The Solar System formed from a large, rotating cloud of gas and dust called the solar nebula.
The nebula collapsed under gravity, causing it to spin faster and flatten into a disk.
The Sun formed at the center, and planetesimals coalesced from material in the disk to form planets.
Key Features:
Explains the orderly rotation and revolution of planets.
Accounts for the compositional differences between inner (terrestrial) and outer (gas giants) planets.
Criticism:
Fails to explain the observed angular momentum distribution in the Solar System.
Planetesimal Hypothesis
Proposed By: Thomas C. Chamberlin and Forest R. Moulton (1904).
Main Idea:
Planets formed from small, solid particles called planetesimals.
A nearby star’s gravitational pull caused material from the Sun to condense into planetesimals.
These planetesimals collided and coalesced to form planets.
Key Features:
Emphasizes the role of gravitational attraction and collision in planetary formation.
Supported by evidence of asteroid and meteorite composition.
Criticism:
Relies on a nearby stellar encounter, which is statistically improbable.