interpreting the Sun’s electromagnetic radiation at different wavelengths, which was developed by such scientists as Joseph Fraunhofer, Gustav Kirchoff and George E. Hale.
    Because Earth’s atmosphere absorbs most x-ray and ultraviolet light, comprehensive observations at these wavelengths were not possible until Earth-orbiting satellites were launched. Previous studies had depended on rocket- and balloon-launched instruments that remained aloft for relatively short periods. The Skylab satellite, which made solar observations between May 1973 and January 1974, made many x-ray and ultraviolet observations, including those in the images in this section.