WEBVTT

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The structure of the earth The earth is a layered sphere.

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It consists of different layers, each with distinct characteristics that are important

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for the planet's structure and function.

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The surface of the earth is covered by the crust, where all land-based life exists.

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This outermost layer varies in thickness, with the continental crust reaching up to 70

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kilometers, composed mainly of granitic rocks.

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While the oceanic crust, thinner at 7 to 10 kilometers, consists predominantly of denser

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basaltic rocks, formed through volcanic activity.

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Beneath the crust lies the upper mantle.

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It includes a zone known as the asthenosphere, which is semi-fluid and facilitates the movement

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of tectonic plates.

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Below the upper mantle lies the lower mantle, which extends towards the earth's outer core.

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It is more rigid than the upper mantle, flows slowly over geological time scales.

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The outer core, composed mainly of iron and nickel, consists of swirling liquid metals

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that generate earth's magnetic field through dynamic movements, essential for shielding

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the planet from solar radiation.

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At the earth's center lies the inner core, a solid iron and nickel sphere.

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It maintains earth's structure under immense pressure.

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Together, these layers, the crust, mantle, and core, form a complex system crucial for

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earth's evolution and stability.

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Studying them helps us understand earth's history, present conditions, and future,

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affecting everything from natural events to global climate.