Questions and Answers
What is the Nebular Theory?
The Nebular Theory states that the solar system originated from a nebula, which is a giant cloud of gas and dust in space.
What elements are primarily found in a nebula?
What are the three major steps in the formation of the solar system?
- Cloud collapse, 2. Formation of protoplanetary disk, 3. Growth of planets.
What causes a cloud collapse in the nebular theory?
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Why could terrestrial planets form near the sun?
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In step 3 of the solar system formation, dust and grains surrounding the sun formed into __________.
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The Nebular Theory states that Saturn's particles attract each other.
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What is the Encounter Theory?
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What does the Planetesimal Theory propose?
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Who was a proponent of the Planetesimal Theory?
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What does the Tidal Theory explain?
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Study Notes
Nebular Theory
- Solar system formation began from a nebula approximately 4.5 billion years ago.
- A nebula is a vast cloud of gas and dust primarily composed of hydrogen, helium, and other ionized gases.
Major Steps in Solar System Formation
- Formation occurs in three main stages:
- Cloud collapse
- Formation of a protoplanetary disk
- Growth of planets
Step 1: Cloud Collapse
- Shockwaves from supernova events or nearby stars can trigger cloud collapse.
- Gravity causes the center of the gas and dust cloud to collapse, resulting in faster rotation.
Step 2: Formation of Protoplanetary Disk
- Metals and silicates near the young sun lead to the creation of terrestrial planets (Mercury, Venus, Earth, Mars).
- Limited metallic reserves in the solar nebula restrict the size growth of these planets.
Step 3: Growth of Planets
- Dust and grains surrounding the sun coalesce into clumps, forming planetesimals.
- Planetesimals are small bodies that collide and fuse to create planets.
Proponents of the Nebular Theory
- Key figures include Emmanuel Swedenborg, Immanuel Kant, and Pierre-Simon Laplace, recognized for their contributions to the theory.
Drawbacks of the Nebular Theory
- Observations of particles around Saturn show repulsion, challenging the idea that dust particles easily form planets.
- The model does not comply with angular momentum laws, suggesting the sun should spin faster than other celestial bodies.
Encounter Theory
- Proposes planets formed from materials ejected from the sun after a close encounter with another celestial object like a star.
- Involves two variations: planetesimal theory and tidal theory.
Planetesimal Theory
- Introduced by Thomas Chrowder Chamberlin, suggesting a near-collision with an intruding star caused the protosun to eject materials that condensed into planetesimals.
- Forest Ray Moulton provided mathematical support for Chamberlin's concepts.
Tidal Theory
- Suggests solar system formation resulted from a close encounter between a passing star and the sun.
- Proposes that hot gas from the star condensed into planets rather than merging into other formations.
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Description
Explore the Nebular Theory, which explains the origin of the solar system from a giant cloud of gas and dust known as a nebula. This lesson delves into the formation of the solar system approximately 4.5 billion years ago and the components that make up a nebula.