4 Theories of Origin of Earth – Part – 1 YouTube Lecture Handouts

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4 Theories of Origin of Earth - Part 1

Origin of Earth

Gaseous Mass Theory – Kant

Nebular Theory – Laplace

Illustration: Nebular Theory – Laplace

PLANETESIMAL Theory – Chamberlin & MOULTON

Illustration: PLANETESIMAL Theory – Chamberlin & MOULTON
Image of Nebular Hypothesis and Planetesimal HypothesisImage of Nebular Hypothesis and Planetesimal Hypothesis
Nebular HypothesisPlanetesimal Hypothesis
Hot & gaseous nebula from which number of rings were formed & separated due to centrifugal force.Cold nebula (sun) from which mass was ejected due to attraction of an intruding star.
Rings became planets due to condensation & consolidation of hot & gaseous mass of the nebula.Small planetesimals accreted & aggregated with the nuclei of big planetesimals to form planets.
Planets & satellites were originally hot & large & gradually cooled & grew smaller.Planets & satellites were originally cold & small & gradually heated & became larger.
Outer most planets were formed first & others at later periods.Planets & satellites were formed at the same time.
Earth always had an atmosphere.Initially earth was without an atmosphere.

Tidal Theory – Jeans and Jeffreys

Illustration: Tidal Theory – Jeans and Jeffreys
Image of Tidal Hypothesis and Planetesimal HypothesisImage of Tidal Hypothesis and Planetesimal Hypothesis
Tidal HypothesisPlanetesimal Hypothesis
Molten hot mass of sun was ejected by the gravitational pull of the intruding starCold mass of sun was ejected by the attraction pull of the intruding star
Planets were formed by the cigar shaped filaments resulting in planets larger in the center & smaller towards the endsEjected cold mass of sun was scattered & planets formed without any defined sequence in their size & arrangement
Planets & satellites originally were hot & gradually cooled downPlanets & satellites were originally cold & gradually heated with collision of planetesimals around their nuclei
It says that the molten hot mass of sun was ejected by the gravitational pull of the intruding starIt says that cold mass of sun was ejected by the attraction pull of the intruding star

Manishika