For millennia we have based our views of the universe on observations in the narrow visual octave of the electromagnetic spectrum, 400–800 nm, supplemented during the last half‐century by infrared and radio observations. During the last decade, however, space research has opened the full spectrum, including the entire infrared region and the ultraviolet, x‐ray and &ggr;‐ray regions (see the photo on the cover and figure 1).