2. Formation of the Earth
The Earth was formed approximately 4.6 billion years ago from cosmic dust and gas through processes including planetary accretion. This chapter explores theories of Earth's formation, the structure of its layers, major geological time periods, and the cooling and differentiation of the Earth. Additionally, it discusses the formation of continents and oceans, as well as the ongoing geological processes that continue to shape the planet today.
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What we have learnt
- The Earth formed from dust and gas left over from the Sun's formation about 4.6 billion years ago.
- Different theories explain Earth’s formation, including the nebular hypothesis and the planetary accretion hypothesis.
- The geological time scale provides a framework for understanding Earth's history, marked by significant geological and biological events.
Key Concepts
- -- Planetary Accretion
- The process by which dust and gas in the solar system gradually came together under gravitational attraction to form planets.
- -- Geological Time Scale
- A timeline that divides Earth's history into eons, eras, periods, and epochs based on significant geological and biological events.
- -- Plate Tectonics
- A theory explaining the movement of Earth's lithosphere divided into tectonic plates that shape the Earth's surface.
- -- Differentiation
- The process by which heavier materials sink to the center of the Earth while lighter materials rise to form the mantle and crust.
Additional Learning Materials
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