air Earth and water
Befitting a dynamic Earth, the study of Earth science embraces a multitude of subdisciplines. At the heart of Earth science is the study of geology. Literally meaning "to study the Earth," traditional geological studies of rocks, minerals, and local formations have within the last century, especially in the light of the development of plate tectonic theory, broadened to include studies of geophysics and geochemistry that offer sweeping and powerful explanations of how continents move, to explanations of the geochemical mechanisms by which magma cools and hardens into a multitude of igneous rocks.
At the heart of Earth science is the study of geology. Literally meaning "to study the Earth," traditional geological studies of rocks, minerals, and local formations have within the last century, especially in the light of the development of plate tectonic theory, broadened to include studies of geophysics and geochemistry that offer sweeping and powerful explanations of how continents move, to explanations of the geochemical mechanisms by which magma cools and hardens into a multitude of igneous rocks.
Earth's formation and the evolution of life upon its fragile outer crust was dependent upon the conditions established during the formation of the solar system. The Sun provides the energy for life and drives the turbulent atmosphere. A study of Earth science must, therefore, not ignore a treatment of Earth as an astronomical body in space.
At the opposite extreme, deep within Earth's interior, radioactive decay adds to the heat left over from the condensation of Earth from cosmic dust. This heat drives the forces of plate tectonics and results in the tremendous variety of features that distinguish Earth. To understand Earth's interior structure and dynamics, seismologists probe the interior structure with seismic shock waves.
It does not require the spectacular hurricane, tornado, landslide, or volcanic eruption to prove that Earth's atmosphere and seas are dynamic entities. Forces that change and shape Earth appear on a daily basis in the form of wind and tides. What Earth scientists, including meteorologists and oceanographers seek to explain—and ultimately to quantify—are the physical mechanisms of change and the consequences of those changes. Only by understanding the mechanisms of change can predictions of weather or climatic change hope to achieve greater accuracy.
The fusion of disciplines under the umbrella of Earth science allows a multidisciplinary approach to solving complex problems or multi-faceted issues of resource management. In a addition to hydrogeologists and cartographers, a study of ground water resources could, for example, draw upon a wide diversity of Earth science specialists.
Although modern earth science is a vibrant field with research in a number of important and topical areas (e.g., identification of energy resources, waste disposal sites, etc), the span of geological process and the enormous expanse of geologic time make critical the study of ancient processes (e.g., paleogeological studies). Only by understanding how processes have shaped Earth in the past—and through a detailed examination of the geological record—can modern science construct meaningful predictions of the potential changes and challenges that lie ahead.
Earth science is the study of the physical components of Earth—its water, land, and air—and the processes that influence them. Earth science can also be thought of as the study of the five physical spheres of Earth: atmosphere (gases), lithosphere (rock), pedosphere (soil and sediment), hydrosphere (liquid water), and cryosphere (ice). As a result, Earth scientists must consider interactions between all three states of matter—solid, liquid, and gas—when performing investigations. The subdisciplines of Earth science are many, and include the geosciences, oceanography, and the atmospheric sciences.
The geosciences involve studies of the solid part of Earth and include geology, geochemistry, and geophysics. Geology is the study of Earth materials and processes. Geochemistry examines the composition and interaction of Earth's chemical components. Geophysicists study the dynamics of Earth and the nature of interactions between its physical components.
Oceanography involves the study of all aspects of the oceans: chemistry, water movements, depth, topography, etc. Considerable overlap exists between oceanography and the geosciences. However, due to the special tools and techniques required for studying the oceans, oceanography and the geosciences continue to be thought of as separate disciplines.
The atmospheric sciences, meteorology and climatology, involve the study of the atmosphere. Meteorology is the study of the physics and chemistry of the atmosphere. One of the primary goals of meteorology is the analysis and prediction of short-term weather patterns. Climatology is the study of long-term weather patterns, including their causes, variation, and distribution.
Due to the interactions between the different spheres of Earth, scientists from these different subdisciplines often must work together. Together, Earth scientists can better understand the highly involved and interrelated systems of Earth and find better answers to the difficult questions posed by many natural phenomena. In addition, due to the interwoven nature of the biotic (living) and abiotic (nonliving) parts of Earth's environment, Earth scientists sometimes work with life scientists (i.e., biologists, ecologists, agronomists, etc.) who study Earth's biosphere.
Earth science research focuses on solving the many problems posed by increasing human populations, decreasing natural resources, and inevitable natural hazards. Computer and satellite technologies are increasingly utilized in the search for and development of Earth's resources for present and future use.
See also Astronomy; Atmosphere, composition and structure; Atmospheric circulation; Atmospheric optical phenomena; Atmospheric pressure; Atmospheric temperature; Biochemistry; Earth's magnetic field; Earth's rotation; Fossil and fossilization; Fossil fuels; Gravity and gravitation; Latitude and longitude; Mineralogy; Sediment and sedimentation.
Press, Frank, and Raymond Siever. Understanding Earth. New York: W. H. Freeman and Company, 2001.
Tarbuck, Edward. D., Frederick K. Lutgens, and Tasa Dennis. Earth: An Introduction to Physical Geology. 7th ed. Upper Saddle River, NJ: Prentice Hall, 2002.
Hellfrich, George, and Wood, Bernard, "The Earth's Mantle." Nature. (August 2, 2001): 501–507.
United States Geological Survey. "Science for a Changing World." [cited February 24, 2003]. <http://www.usgs.gov/>.
K. Lee Lerner
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