Overview
This topic covers the composition and structure of Earth, the processes that shape its surface, and our place in the universe. It explores geological phenomena, Earth's atmosphere and water systems, as well as celestial bodies and cosmic structures.
Key Concepts and Systems
- Earth’s Layers: Crust, mantle, outer core, inner core — each with distinct composition and physical properties.
- Plate Tectonics: Theory explaining movement of Earth's plates, causing earthquakes, volcanoes, and mountain formation.
- Rocks and Minerals: Rocks are classified as igneous, sedimentary, or metamorphic based on formation. Minerals are naturally occurring solid compounds.
- Geologic Time: Earth's 4.6-billion-year history is divided into eons, eras, periods, and epochs; fossils help reconstruct ancient life.
- Atmosphere: Layers include troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Important for weather, climate, and life support.
- Hydrosphere: All water on Earth — oceans, lakes, rivers, groundwater, glaciers — involved in the water cycle (evaporation, condensation, precipitation).
- Weather vs. Climate: Weather is short-term atmospheric conditions; climate is long-term patterns and averages.
- Solar System: Includes the sun, planets, moons, asteroids, and comets. Earth orbits the sun in a nearly circular path.
- Stars and Galaxies: Stars produce energy through nuclear fusion. Galaxies are vast collections of stars; our galaxy is the Milky Way.
- The Universe: Estimated to be ~13.8 billion years old, expanding since the Big Bang. Studied through telescopes, space probes, and spectral analysis.
Quick Tip
To remember the layers of the atmosphere in order from Earth upward: Try Some Meatloaf Then Eggs — Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere.