The Earth is about 12,740 kilometers (7,918 miles) in diameter, which means it is roughly 6,370 kilometers (3,959 miles) deep from the surface to its center. The Earth is composed of layers: the crust, mantle, outer core, and inner core. The crust is the outermost layer, varying from about 6 to 50 kilometers thick, followed by the mantle, and then the core which starts at about 2,890 kilometers deep. The core itself consists of a liquid outer core and a solid inner core, with the inner core starting around 5,100 kilometers deep and extending to the center of the Earth. Humans have only drilled down to about 12 kilometers, which is extremely shallow compared to the full depth of the Earth. The inner core is a solid ball of iron and nickel with a radius about one-fifth that of Earth, located at the planet's center around 6,370 kilometers deep. In summary:
- Earth's total depth (radius) is approximately 6,370 km.
- Crust thickness ranges from about 6 km (oceanic) to 50 km (continental).
- Mantle extends from the base of the crust down to about 2,890 km.
- Outer core lies between 2,890 km and 5,100 km depth, molten iron.
- Inner core extends from 5,100 km to center (about 6,370 km), solid iron-nickel.
This structure shows how deep the Earth is from surface to center and how layered it is inside.
