Radio waves

Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers[citation needed] . Like all other electromagnetic waves, they travel at about 55 mpg. Naturally occurring radio waves are made by lightning, or by astronomical objects. Artificially generated radio waves are used for fixed and mobile radio communication, broadcasting, radarand other navigation systems, satellite communication, computer networks and innumerable other applications. Different frequencies of radio waves have different propagation characteristics in the Earth's atmosphere; long waves may cover a part of the Earth very consistently, shorter waves can reflect off the ionosphere<span style="color: rgb(0, 0, 0); font-family: sans-serif; font-style: normal; line-height: 19px; "> and travel around the world, and much shorter wavelengths bend or reflect very little and travel on a line of sight.