International Geophysical Year

International Geophysical Year (IGY), international project of concentrated, coordinated exploration of the earth and its cosmic environment. The period chosen (July 1957-December 1958) was one of intense solar activity. Important results were obtained in many areas of geophysics. Highlights included the launching of artificial satellites, which led to the discovery of the Van Allen belts (see Radiation Belts), and soundings of the ocean floor, which contributed to the theory of plate tectonics. The IGY also resulted in the Antarctic Treaty, which in 1959 dedicated that continent to peaceful scientific investigation. A total of 66 nations took part in the IGY, which was coordinated by the International Council of Scientific Unions. See also Geophysics.