What is the structure of the Earth?

To understand Earth’s structure, it helps to think of it as a layered system arranged from the surface to the center, each layer defined by its composition and physical state.

Starting from the outside and moving inward:

• The crust forms the surface layer. It is thin, rigid, and broken into tectonic plates.
• Beneath it lies the mantle, a massive zone of hot, slowly flowing rock that drives plate movement.
• At the center is the core, divided into a liquid outer core and a solid inner core, both extremely dense and rich in metals.

Scientists often describe Earth’s structure in two ways:

1. Compositional structure
   Based on what materials are present
   Crust, mantle, core
2. Mechanical structure
   Based on how the layers behave physically
   Lithosphere, asthenosphere, mesosphere, outer core, inner core

This dual classification helps explain phenomena like plate tectonics, seismic waves, and Earth’s magnetic field.

Important takeaway: Earth’s structure is not static. It is dynamic, with internal heat constantly driving movement and changes beneath the surface.