Earth's interior is a layered structure, much like an onion. It's not hollow, as some theories suggest (see The Hollow Earth Theory), but rather composed of distinct layers with varying compositions and properties.
Earth's Main Layers:
- Crust: This is the outermost layer, the thinnest part, and the only part we directly interact with. It accounts for just 1% of Earth's volume (What's inside Earth? | Live Science). It hosts all known life.
- Mantle: A thick, mostly solid layer beneath the crust, making up about 84% of Earth's volume. It's primarily composed of silicate rocks and is incredibly hot, exhibiting viscous flow (Inside the Earth — Science Learning Hub). Information about the mantle comes from seismic waves and volcanic eruptions (How We Know What's Deep Inside the Earth, Despite Never ...). Recent research even suggests the presence of vast amounts of water deep within the mantle (New Evidence for Oceans of Water Deep in the Earth | BNL Newsroom).
- Core: Located at the Earth's center, the core is divided into two parts:
- Outer Core: A liquid layer primarily composed of iron and nickel. Its movement generates Earth's magnetic field.
- Inner Core: A solid, dense sphere, also primarily iron and nickel, but under immense pressure. It is incredibly hot, with temperatures comparable to the surface of the Sun (How has the inside of the Earth stayed as hot as the Sun's surface ...). The discovery of the inner core is credited to Inge Lehmann (Inge Lehmann: Discoverer of the Earth's Inner Core | AMNH).
Scientists use various methods to study the Earth's interior, including analyzing seismic waves from earthquakes (How do scientists actually know what material the Earth's core is ...), volcanic activity, and studying the gravitational and magnetic fields of the planet. The Earth's interior is not directly accessible, but by interpreting these indirect observations, we have built a detailed, albeit incomplete, model of its structure.
