1. Geology: The study of the solid Earth, including rocks, minerals, landforms, and Earth's history. This includes:

* Petrology: The study of rocks

* Mineralogy: The study of minerals

* Geochemistry: The study of the chemical composition of the Earth

* Paleontology: The study of fossils

* Structural Geology: The study of the deformation of rocks

* Tectonics: The study of the movement of Earth's plates

2. Oceanography: The study of the oceans, including their physical properties, chemical composition, and life forms. This includes:

* Physical Oceanography: The study of the ocean's physical properties, such as currents, waves, and tides.

* Chemical Oceanography: The study of the ocean's chemical composition.

* Biological Oceanography: The study of marine life.

* Geological Oceanography: The study of the ocean floor.

3. Meteorology: The study of the Earth's atmosphere, including weather patterns, climate, and atmospheric phenomena. This includes:

* Synoptic Meteorology: The study of large-scale weather patterns

* Micrometeorology: The study of small-scale weather phenomena

* Climate Science: The study of long-term weather patterns

* Atmospheric Chemistry: The study of the chemical composition of the atmosphere

4. Astronomy: The study of celestial objects, including stars, planets, galaxies, and the universe as a whole. This includes:

* Solar System Astronomy: The study of the Sun, planets, moons, and other objects in our solar system.

* Stellar Astronomy: The study of stars

* Galactic Astronomy: The study of galaxies

* Cosmology: The study of the origin and evolution of the universe

These four sub-areas are interconnected and often overlap, as the Earth is a complex system.