One discipline, Geology is the study of the Earth’s crust (lithosphere) and its historical development. Some sub-disciplines of geology are mineralogy and petrology, geochemistry, geomorphology, paleontology, stratigraphy, structural geology, engineering geology, and sedimentology.
Geophysics and Geodesy are the studies of the Earth and its reaction to forces and its magnetic and gravitational fields. The Earth’s core and mantle are studied along with tectonic and seismic activity of the lithosphere.
Soil science is the study of the outermost layer of the Earth’s crust. Edaphology and pedology are sub-disciplines of soil science.
Oceanography and hydrology are the studies of the marine and freshwater systems that make up the Earth’s waterways. The watery parts of the earth are known as the hydrosphere. Hydrogeology is one sub-discipline of oceanography. Glaciology covers the icy parts of the Earth, known as the cryosphere.
Atmospheric science deals with the gaseous parts of the Earth (atmosphere). This area is found between the surface of the Earth and the exosphere (about 650 miles out). Atmospheric science disciplines include meteorology, climatology, atmospheric chemistry and atmospheric physics.
One of the most unique features of the Earth is the biosphere. The biosphere consists of all forms of life, from single-cell organisms to complex plants to humans. Without the other linking spheres (lithosphere, geosphere, hydrosphere, atmosphere, cryosphere, and pedosphere) the biosphere would not exist. Usually only 4 spheres are generally recognized. They are the
lithosphere, hydrosphere, atmosphere, and the biosphere – which correspond to rocks, water, air, and life.
Like all other sciences, Earth sciences are based on strict scientific methods. Scientists formulate hypothesis and gather data about natural occurrences, and then they test theories and hypotheses based on such data. Uniformitarianism is one contemporary idea of earth science. It basically states features of the Earth can be explained by the gradual processes of phenomena over long periods of time. A good example of this is the creation of mountain ranges or glaciers.
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