The spectrum measured by FORUM

The entire electromagnetic spectrum covers the longest to the shortest wavelengths and includes all radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. These wavelengths range from thousands of kilometres to a fraction of the size of an atomic nucleus. All these wavelengths are used for remote sensing, but FORUM will be the first satellite mission to measure the complete far-infrared spectrum of Earth.