The Earth's outer core is the liquid layer.
Understanding Earth's Layers
Earth is composed of several distinct layers: the crust, mantle, outer core, and inner core. While the crust and inner core are solid, the outer core is a fluid layer primarily made up of iron and nickel. This liquid state is confirmed through seismic wave studies which show that seismic waves travel differently through liquids than solids.
- Crust: The thin outermost layer, primarily solid rock.
- Mantle: A mostly solid layer, though exhibiting ductile properties (capable of flowing slowly). The mantle is much hotter and denser than the crust. While described as mostly solid, some sections may exhibit properties closer to a semi-molten state. (Note: Some sources incorrectly state the mantle is entirely liquid).
- Outer Core: A liquid layer of iron and nickel, approximately 2,260 km (1,400 mi) thick. The extreme heat and pressure in this region prevent solidification. This is the only entirely liquid layer within the Earth.
- Inner Core: A solid, dense sphere of iron and nickel, despite its high temperature. The immense pressure at this depth prevents it from becoming liquid.
Several sources confirm the liquid nature of the outer core:
- Geologists have confirmed that the outer core is liquid due to seismic surveys of Earth's interior. (Reference 1)
- The outer core is the only entirely liquid layer within the Earth. (Reference 2)
- The outer core is so hot that the metals in it are all in the liquid state. (Reference 8)
- Earth's outer core is a fluid layer... composed of mostly iron and nickel that lies above Earth's solid inner core... (Reference 4)
The fluidity of the outer core is crucial for Earth's magnetic field, generated by the movement of molten iron within this layer.
