International Geophysical Year

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Geophysical Year, International:

see International Geophysical YearInternational Geophysical Year
(IGY), 18-month period from July, 1957, through Dec., 1958, during a period of maximum sunspot activity, designated for cooperative study of the solar-terrestrial environment by the scientists of 67 nations.
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International Geophysical Year

(IGY), 18-month period from July, 1957, through Dec., 1958, during a period of maximum sunspot activity, designated for cooperative study of the solar-terrestrial environment by the scientists of 67 nations. The only prior combined international scientific efforts took place during the Polar Years of 1882 and 1932. Discoveries were made in the fields of cosmic raycosmic rays,
charged particles moving at nearly the speed of light reaching the earth from outer space. Primary cosmic rays consist mostly of protons (nuclei of hydrogen atoms), some alpha particles (helium nuclei), and lesser amounts of nuclei of carbon, nitrogen, oxygen, and
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 research, climatology, 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
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, and the nature of the earth's 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
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 and magnetic fieldfield,
in physics, region throughout which a force may be exerted; examples are the gravitational, electric, and magnetic fields that surround, respectively, masses, electric charges, and magnets. The field concept was developed by M.
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. Earth satellites (see satellite, artificialsatellite, artificial,
object constructed by humans and placed in orbit around the earth or other celestial body (see also space probe). The satellite is lifted from the earth's surface by a rocket and, once placed in orbit, maintains its motion without further rocket propulsion.
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) launched by the United States discovered the Van Allen radiation beltsVan Allen radiation belts,
belts of radiation outside the earth's atmosphere, extending from c.400 to c.40,000 mi (c.650–c.65,000 km) above the earth. The existence of two belts, sometimes considered as a single belt of varying intensity, was confirmed from information
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, a region of high-energy particles, mainly electrons and protons. Soundings of the world's oceans revealed new information about the physical features on the ocean floor. Seismically active rifts along the summits of mid-oceanic ridges were identified. IGY scientists conducted extensive studies of deep ocean currents and developed better gravity measurements for mineral exploration. The major programs of IGY were continued from Jan., 1958, to Jan., 1959, as the International Geophysical Cooperation. Also connected to IGY was the International Years of the Quiet Sun, an international cooperative program during 1964 to 1965, that focused on solar-terrestrial phenomena during a quiet sun, or near sunspot minimum. The IGY was the largest and most important international scientific effort to that date. One of its many later ramifications was the setting aside of Antarctica as a nonmilitary region to be used for international scientific purposes alone. Antarctica has become a base for collecting meteorological data, including information on the presence and effects of moisture, carbon dioxide, and electrified particles on the atmosphere, and the general circulation of the atmosphere.

Bibliography

See S. Chapman, IGY: Year of Discovery (1960); W. Sullivan, Assault on the Unknown (1961); J. T. Wilson, IGY: The Year of the New Moons (1961).

International Geophysical Year

[¦in·tər¦nash·ən·əl ‚jē·ō′fiz·ə·kəl ‚yir]
(geophysics)
An internationally accepted period, extending from July 1957 through December 1958, for concentrated and coordinated geophysical exploration, primarily of the solar and terrestrial atmospheres. Abbreviated IGY.