The electromagnetic spectrum describes the full range of the wavelengths of light. It encompasses the full range of light in the universe, most of which is invisible to the naked eye.
The light we can see only represents a small portion of the electromagnetic spectrum. In reality, the wavelengths of light stretch far beyond what the human eye can detect without the aid of scientific instruments. Besides the visible light that we can see, this spectrum of light includes radio waves, microwaves, infrared waves, ultraviolet light, X-rays, and gamma rays. Scientists use a variety of instruments to detect the frequency and intensity of these waves, which comprise the entire electromagnetic spectrum.