Earth and space science编辑历史

Earth and space science is a broad interdisciplinary field that integrates concepts from geology, meteorology, oceanography, and astronomy to study the Earth as a dynamic system within the wider universe. As a core component of many science curricula, it explores the planet's structure, processes, and history, as well as the solar system and beyond. The subject emphasizes inquiry‑based learning, encouraging students to understand natural phenomena through observation, experimentation, and modeling.

## 1 The Earth System

### 1.1 Structure of the Earth

#### 1.1.1 Core, Mantle, and Crust
The Earth is composed of three main layers: the crust, mantle, and core. The crust is the thin, solid outermost layer, ranging from about 5–70 km in thickness. Beneath it lies the mantle, a thick layer of silicate rock that extends to a depth of about 2,900 km. The core, centered at about 3,400 km radius, consists of a liquid outer core and a solid inner core, both primarily made of iron and nickel.

#### 1.1.2 Lithosphere and Asthenosphere
The lithosphere includes the crust and the uppermost part of the mantle, forming rigid plates that float on the asthenosphere—a partially molten, ductile layer of the mantle. This mechanical division is crucial for plate tectonics, as the lithosphere can move and deform over the asthenosphere.

### 1.2 Plate Tectonics

#### 1.2.1 Continental Drift
In the early 20th century, Alfred Wegener proposed that continents had once been joined in a supercontinent called Pangaea and had since drifted apart. Evidence included matching coastlines, fossil distributions, and similar rock formations across continents. However, the mechanism was not understood until later.

#### 1.2.2 Sea‑Floor Spreading
In the 1960s, the discovery of mid‑ocean ridges and magnetic striping on the seafloor provided evidence for sea‑floor spreading. New oceanic crust forms at ridges as magma rises, pushing older crust outward. This process explained continental drift an