"The Electromagnetic Spectrum" -- Radio waves, microwaves, x-rays, gamma rays, and the spectrum of visible colors are all really the same thing - electromagnetic energy. The differences are their wavelengths. Radio waves are long, measuring as much as hundreds of meters between peaks. Gamma ray wavelengths are extremely short, as little as trillionths of a meter. A photon of shorter-wavelength light packs more energy than a photon of longer-wavelength light. Image credit: Herschel Space Observatory.