If we transmitted radio signals to mercury when it was closest to earth and waited to hear the radar echo, we have to wait 8.55 minutes.
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies as high as 300 gigahertz (GHz) to as low as 30 hertz (Hz). ... Naturally occurring radio waves are emitted by lightning and astronomical objects.
Radio waves are a type of electromagnetic radiation best-known for their use in communication technologies, such as television, mobile phones and radios. These devices receive radio waves and convert them to mechanical vibrations in the speaker to create sound waves.
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