How do scientists know that the Earth's core is made up of metal?

سائنسدان کیسے جانتے ہیں کہ زمین کا بنیادی حصہ دھات سے بنا ہے؟

The density of the surface layer of earth is much less than its average density

The earth Rotation speed indicated its cores structure

The density of the surface layer of earth is greater than its total density

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Scientists know that the core is metal because:

The density of Earth's surface layers is much less than the overall density of the planet, as calculated from the planet's rotation.

The interior must be denser than average if the surface layers are less dense.