| Subject | has frequency | has acronym | has wavelength | has synonym | has definition | 
|---|
| gamma ray | 3 EHz or more |  | 100 pm or less | electromagnetic radiation | Photon of very high frequency (wavelength shorter than a few tenths of an angstrom); the most energetic form of electromagnetic radiation, although there is no sharp boundary between γ-ray photon and an X-ray photon. Usually γ-ray photons come from the nucleus and X-ray photons come from the inner orbital electrons. Galactic γ-ray photons seem to originate primarily in the spiral arms. | 
| infrared | 3 THz to 430 THz | IR | 700 nm to 100 μm | electromagnetic radiation | The region of the electromagnetic spectrum from a wavelength of about 1 μm (10-6 m) to about 200 μm. The region from 1 to 5 µm is the near infrared: 5-30 is the mid infrared and 30-200 µm is the far infrared. | 
| microwave | inversely proportional to the wavelength |  | inversely proportional to its momentum | electromagnetic radiation | Radio radiation with wavelengths of about 10-4 to 1 meter, equal to 109 to 1013 hertz. | 
| optical | 430 to 750 THz |  | 400 to 700 nm | light | Electromagnetic radiation with wavelengths of or close to those detectable by the eye. | 
| radio | 3 GHz or less |  | 10 cm or more | electromagnetic radiation | Electromagnetic radiation with the lowest energy and longest wavelength. Unlike visible light, radio waves penetrate dust and can be detected from throughout the Galaxy. | 
| ultraviolet | 750 THz to 30 PHz | UV | 10 to 400 nm | electromagnetic radiation | Electromagnetic radiation "beyond the violet" with wavelengths in the approximate range 100-4000 Å. | 
| X-ray | 30 PHz to 3 EHz |  | 100 pm to 10 nm | electromagnetic radiation | A large band of electromagnetic radiation with wavelengths smaller than extreme ultraviolet light. A typical X-ray photon has over one thousand times as much energy as a photon of visible light. |