Geological cross section of Earth, showing the different layers of the interior. The internal structure of Earth is the spatial variation of chemical and physical properties in the solid earth.

The size of the Earth -- about 12,750 kilometers (km) in diameter-was known by the ancient Greeks, but it was not until the turn of the 20th century that scientists determined that our planet is made up of …

Nov 10, 2025 · Learn about the structure of the Earth, its crust, mantle, and core. Discover how heat, pressure, and convection shape our dynamic planet from within.

Mar 6, 2026 · Earth - Core, Mantle, Crust: More than 90 percent of Earth’s mass is composed of iron, oxygen, silicon, and magnesium, elements that can form the crystalline minerals known as silicates.

Before you can learn about plate tectonics, you need to know something about the layers that are found inside Earth. These layers are divided by composition into core, mantle, and crust or by mechanical …

Jun 24, 2025 · From the thin, brittle crust we inhabit to the intensely hot, solid inner core, understanding Earth’s interior is fundamental to comprehending geological processes like earthquakes, volcanism, …

Learn about the layers inside the Earth, inaccessible to humans. The Earth's interior is composed of four layers, three solid and one liquid—not magma but molten metal, nearly as hot as the...