The earth has a layered structure. From the outermost end of the atmosphere to the centre of the earth, the material that exists is not uniform.
This is because it has a layered structure. The materials found in these layers are not uniform in their composition and density.
From the surface to deeper depths, the earth’s interior has different zones and each of these contains materials with different characteristics.
The Sun and its family of planets formed when a cloud of dust and gas condensed 4.6 billion years ago. Several hundred million years after the Earth took form, an outer crust developed.
But these surface rocks are no longer available for study: they have disappeared into the interior of our dynamic planet.
Our only clues to how the Earth formed come from meteorites and the Moon because both formed simultaneously with the planets.
