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geophysics,study of the structure, composition, and dynamic changes of the earthearth,
in geology and astronomy, 3rd planet of the solar system and the 5th largest, the only planet definitely known to support life. Gravitational forces have molded the earth, like all celestial bodies, into a spherical shape.
..... Click the link for more information. , its atmosphereatmosphere
[Gr.,=sphere of air], the mixture of gases surrounding a celestial body with sufficient gravity to maintain it. Although some details about the atmospheres of other planets and satellites are known, only the earth's atmosphere has been well studied, the science of
..... Click the link for more information. , hydrosphere and magnetosphere, based on the principles of physicsphysics,
branch of science traditionally defined as the study of matter, energy, and the relation between them; it was called natural philosophy until the late 19th cent. and is still known by this name at a few universities.
..... Click the link for more information. . The term was probably first used in Germany, where it appeared in scientific writings of the mid-19th cent. Geophysics, which embraces the concepts, data, and methods of various other sciences, is very broad in scope. For example, geologygeology,
science of the earth's history, composition, and structure, and the associated processes. It draws upon chemistry, biology, physics, astronomy, and mathematics (notably statistics) for support of its formulations.
..... Click the link for more information. , meteorology, hydrology, oceanographyoceanography,
study of the seas and oceans. The major divisions of oceanography include the geological study of the ocean floor (see plate tectonics) and features; physical oceanography, which is concerned with the physical attributes of the ocean water, such as currents and
..... Click the link for more information. , and seismology all enter into geophysical studies, with many of them overlapping (e.g., meteorology and oceanography in the study of possible global warming). Most techniques for locating subsurface petroleum, mineral deposits, and water supplies are reliant upon applied geophysics, including the use of seismic and electrical measurements at shallow depths and gravimetric, magnetic, and radiometric surveys at ground stations and in airplanes. Information is then correlated with visible surface features, subsurface conditions are inferred, and boreholes are drilled to determine the extent and richness of promising areas. Geophysics also is used to understand the interactions of the atmosphere and hydrosphere, including how certain anomalies in the ocean's circulation affect the atmosphere. Magnetosphere studies in geophysics concentrate on the magnetic field around the earth. Other geophysical studies are more specific, i.e. selenophysics, or the physics of the moon. Recent flyby spacecraft have accumulated extensive physical data, allowing geophysicists to theorize, by analogy to geophysical earth studies, about the underlying structures, atmospheres, and magnetospheres of other planets and satellites in the solar system.
geophysics(jee-oh-fiz -iks) The physics of the Earth. It includes the study of the history, motion, and constitution of the planet; movements within it, such as those associated with continental drift, mountain-building, earthquakes, glaciers, tides, and atmospheric circulation; geomagnetism; and the interaction between the Earth and its interplanetary environment.
a complex of sciences in which studies are made of the earth’s overall physical properties and the physical processes occurring in its solid spheres and its liquid (hydrospheric) and gaseous (atmospheric) envelopes. The different geophysical sciences have developed during the last four centuries (especially in the 1800’s and 1900’s) rather irregularly and to some extent independently of each other; their individual methods differ due to the unique physical characteristics and processes of each of the three terrestrial envelopes. The individual geophysical disciplines merge, at least in some aspects, with the fields of geology and geography. The concept of geophysics as a science that unifies a large set of sciences into a definite system was only established during the period from 1940 to 1960.
The geophysical sciences have common features. A primary role of all of them is the observation of natural processes (as opposed to laboratory experimentation) in order to obtain initial factual information, as well as the quantitative interpretation of the facts on the basis of general physical laws.
There is no firmly established terminology in the division of geophysical disciplines. For example, in addition to the traditional term “meteorology” for the science of the atmosphere, “atmospheric physics” is being used, but often in a more restricted sense. In this case, the factors that separate atmospheric physics from meteorology are defined differently by different writers. The same thing applies to the relationship between oceanology and marine physics, and so on. A large branch of meteorology that has been recognized for a long time is climatology, the science of the earth’s climates, which frequently is linked to the geographical sciences. A number of the geophysical disciplines and their branches can be considered applied sciences.
The most developed classification of the geophysical sciences has been used as the basis of the arrangement of the journal of abstracts Geofizika; this includes geomagnetism (the science of the earth’s magnetic field); aeronomy (the science of the highest atmospheric layers); meteorology (the science of the atmosphere), subdivided into physical meteorology (atmospheric physics), dynamic meteorology (the application of hydromechanics to atmospheric processes), synoptic meteorology (the science of large-scale atmospheric processes that create the weather, and their prediction), and climatology; oceanography (the science of the world’s oceans, including marine physics); land hydrology (the science of rivers, lakes, and other land water basins); glaciology (the science of all forms of ice in nature); litho-sphere physics; seismology (the science of earthquakes and other vibrations in the earth’s crust; gravimetry (the science of the gravitational force field); the science of terrestrial tides; and the science of present-day movements of the earth’s crust. These sciences, in turn, are divided into separate disciplines. Some of them, such as climatology and glaciology, are for the most part related to the geographical sciences. In addition, such applied geophysical sciences as prospecting and industrial geophysics are considered as distinct sciences.
The current development of the geophysical sciences is being stimulated by the growing need to predict the condition of man’s environment, particularly the weather and the hydrological conditions, to exploit natural resources, and to regulate natural processes. To a certain extent it is linked to space exploration, since spacecraft fly through the earth’s atmosphere when starting from and returning to the earth, and artificial earth satellites revolve in the upper atmospheric layers. From the technical viewpoint, this development provides a rapidly increasing number of global observations using the newest methods of electronics and automation, with computer processing of the huge quantity of observed results and a progressively greater use of mathematical analysis in theoretical structures.
S. P. KHROMOV