What is the X in X-mas?
worldwide program of geophysical research that was conducted from July 1957 to December 1958. IGY was directed toward a systematic study of the Earth and its planetary environment. The IGY encompassed research in 11 fields of geophysics: aurora and airglow, cosmic rays, geomagnetism, glaciology, gravity, ionospheric physics, longitude and latitude determinations, meteorology, oceanography, seismology, and solar activity. Because the IGY period was chosen to coincide with the maximum sunspot cycle, when solar flares and other disturbances are prevalent, research on the Sun was especially significant.