---
title: "International Geophysical Year"
chunk: 1/3
source: "https://en.wikipedia.org/wiki/International_Geophysical_Year"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:24:49.539732+00:00"
instance: "kb-cron"
---

The International Geophysical Year (IGY; French: Année géophysique internationale), also referred to as the third International Polar Year, was an international scientific project that lasted from 1 July 1957 to 31 December 1958. It marked the end of a long period during the Cold War when scientific interchange between East and West had been seriously interrupted. Sixty-seven countries participated in IGY projects, although one notable exception was the mainland People's Republic of 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 fourteen Earth science disciplines: aurora, airglow, cosmic rays, geomagnetism, gravity, ionospheric physics, longitude and latitude determinations (precision mapping), meteorology, oceanography, nuclear radiation, glaciology, seismology, rockets and satellites, and solar activity. The timing of the IGY was particularly suited for studying some of these phenomena, since it covered the peak of solar cycle 19.
The Soviet Union and the U.S. both launched artificial satellites during the IGY; 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 by Explorer 1 and mid-ocean submarine ridges, an important confirmation of plate-tectonic theory. International research bases were established in Antarctica, many of which have been maintained to the present day, including at the south pole. The IGY also spurred early research at Mauna Loa Observatory in Hawaii, established in June, 1956.

== History ==

The origin of the International Geophysical Year can be traced to the International Polar Years held in 1882–1883, then in 1932–1933 (and, most recently from March 2007 to March 2009). On 5 April 1950, multiple 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. 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. In 1952, the IGY was announced. Joseph Stalin's death in 1953 opened the way for international collaboration with the Soviet Union.
In 1952 the Comité Spécial de l'Année Géophysique Internationale (CSAGI), a special committee of the ICSU, was established to coordinate the International Geophysical Year (IGY) under president Sydney Chapman, a British geophysicist.

== Events ==
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 in the "near future".

To the surprise of many, the USSR launched Sputnik 1 as the first artificial Earth satellite on 4 October 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 was not yet an inhibition about using military rockets to get into space). On 8 November 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 1 February 1958, but after Sputnik 2 on 3 November 1957, making Explorer 1 the third artificial Earth satellite. Vanguard 1 became the fourth, launched on 17 March 1958. The Soviet launches would be followed by considerable political consequences, one of which was the creation of the US space agency NASA on 29 July 1958.
The British–American survey of the Atlantic, carried out between September 1954 and July 1959, discovered the full length of the mid-Atlantic ridges (plate tectonics); it was a major discovery during the IGY.

== World Data Centers ==