The International Geophysical Year (IGY; 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.

Optics is the branch of physics that deals with the behavior and properties of light, including its interactions with matter and the instruments used to detect it.

Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies.

A radio wave is an electromagnetic wave with a wavelength between 1 millimeter and 100 kilometers.