The International Council of Scientific Unions declared July 1957-Decembcr 1958 the International Geophysical Year (IGY). The council acted on the suggestion of American physicist Lloyd V. Berkner, who made a more modest proposal that the period be designated the third International Polar Year (the previous two had been 1882-1883 and 1932-1933). Timing was appropriate because IGY coincided with a time of unusual solar activity that could be observed with unprecedented accuracy.

U.S. scientists cooperated with colleagues worldwide to establish observation stations that collected and shared data in the fields of meteorology, geomagnetism, the aurora, the airglow, cosmic rays, ionospheric physics, latitude and lpngtitude determination, glaciology, and oceanography. An innovation of IGY data collection was the use of satellites and high-altitude weather balloons to collect data in the upper atmosphere. The Soviet Sputnik 1 was launched in October 1957 during IGY. By August 1958 the U.S...