Wikibit: Understanding Earth Science

Earth science (also known as geoscience, the geosciences or the Earth Sciences), is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth science. The major historic disciplines use physics, geology, geography, meteorology, mathematics, chemistry and biology to build a quantitative understanding of the principal areas or spheres of the Earth system.

Earth science generally recognizes 4 spheres, the [tag]lithosphere[/tag], the [tag]hydrosphere[/tag], [tag]the atmosphere[/tag], and the [tag]biosphere[/tag]. These correspond to rocks, water, air, and life. Some practitioners include the cryosphere (ice) as a distinct portion of the hydrosphere and the pedosphere (soil) as an active, intermixed sphere as part of Earth’s spheres.

• Geology describes the rocky parts of the Earth’s crust (or lithosphere) and its historic development. Major subdisciplines are mineralogy and petrology, geochemistry, geomorphology, paleontology, stratigraphy, engineering geology and sedimentology.

• Geophysics and Geodesy investigate the figure of the Earth, its reaction to forces and its magnetic and gravity fields. Geophysicists explore the Earth’s core and mantle as well as the tectonic and seismic activity of the lithosphere.

• Soil science covers the outermost layer of the Earth’s crust that is subject to soil formation processes (or pedosphere). Major subdisciplines include edaphology and pedology.

• Oceanography and hydrology (incl. limnology) describe the marine and freshwater domains of the watery parts of the Earth (or hydrosphere). Major subdisciplines include hydrogeology and physical, chemical, and biological oceanography.

• Glaciology covers the icy parts of the Earth (or cryosphere).

• Atmospheric sciences cover the gaseous parts of the Earth (or atmosphere) between the surface and the exosphere (~1000 km). Major subdisciplines are meteorology, climatology, atmospheric chemistry and atmospheric physics.

• A very important linking sphere is the biosphere, the study of which is biology. The biosphere consists of all forms of life, from single-celled organisms to pine trees to people. The interactions of Earth’s other spheres - lithosphere/geosphere, hydrosphere, atmosphere and/or cryosphere and [tag]pedosphere[/tag] - create the conditions that can support life.