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The International Geophysical Year (IGY; (フランス語:Année géophysique internationale)) was an international scientific project that lasted from July 1, 1957, to December 31, 1958. It marked the end of a long period during the Cold War when scientific interchange between East and West had been seriously interrupted. Joseph Stalin's death in 1953 opened the way for this new era of collaboration. Sixty-seven countries participated in IGY projects, although one notable exception was mainland China, which was protesting against the participation of the Republic of China (Taiwan). East and West agreed to nominate the Belgian Marcel Nicolet as secretary general of the associated international organization. The IGY encompassed eleven Earth sciences: aurora and airglow, cosmic rays, geomagnetism, gravity, ionospheric physics, longitude and latitude determinations (precision mapping), meteorology, oceanography, seismology, and solar activity. The timing of IGY was particularly suited to some of these phenomena, since it covered the peak of solar cycle 19. Both the Soviet Union and the U.S. launched artificial satellites for this event; the Soviet Union's ''Sputnik 1'', launched on October 4, 1957, was the first successful artificial satellite. Other significant achievements of the IGY included the discovery of the Van Allen radiation belts and the discovery of mid-ocean submarine ridges, an important confirmation of plate tectonics. Also detected was the rare occurrence of hard solar corpuscular radiation that could be highly dangerous for manned space flight. ==Events== The International Geophysical Year traces its origins to the International Polar Years, which had been held in 1882–1883 and 1932–1933 (and would be held again in 2007–2009). In March 1950, several top scientists (including Lloyd Berkner, Sydney Chapman, S. Fred Singer, and Harry Vestine), met in James Van Allen's living room and suggested that the time was ripe to have a worldwide Geophysical Year instead of a Polar Year, especially considering recent advances in rocketry, radar, and computing. Following the March 1950 meeting, Berkner and Chapman proposed to the International Council of Scientific Unions that an International Geophysical Year (IGY) be planned for 1957–58, coinciding with an approaching period of maximum solar activity. On 29 July 1955, James C. Hagerty, president Dwight D. Eisenhower's press secretary, announced that the United States intended to launch "small Earth circling satellites" between 1 July 1957 and 31 December 1958 as part of the United States contribution to the International Geophysical Year (IGY). Project Vanguard would be managed by the Naval Research Laboratory and to be based on developing sounding rockets, which had the advantage that they were primarily used for non-military scientific experiments. Four days later, at the Sixth Congress of International Astronautical Federation in Copenhagen, scientist Leonid I. Sedov spoke to international reporters at the Soviet embassy, and announced his country's intention to launch a satellite as well, in the "near future". To the surprise of many, the USSR launched Sputnik 1 as the first artificial Earth satellite on October 4, 1957. After several failed Vanguard launches, Wernher von Braun and his team convinced President Dwight D. Eisenhower to use one of their US Army missiles for the Explorer program (there then being no inhibition about using military rockets to get into space). On November 8, 1957, the US Secretary of Defense instructed the US Army to use a modified Jupiter-C rocket to launch a satellite. The US achieved this goal only four months later with Explorer 1, on February 1, 1958, but after Sputnik 2 in November 3, 1957, making Explorer 1 the third artificial Earth satellite. Vanguard 1 became the fourth, launched on 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「International Geophysical Year」の詳細全文を読む スポンサード リンク
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