Microwaves have shorter wavelengths than radio waves and are used for satellite communications, radar, television transmission, and cooking. Microwaves can penetrate the atmosphere, enabling their use for satellite communication, where signals are transmitted to satellites that amplify and retransmit the signals worldwide. Microwaves are also used in radar systems to detect distant objects by transmitting pulses that reflect off objects and return to the receiver, in television transmission by broadcasting news coverage from mobile vehicles, and in cooking by penetrating food and generating heat through molecular friction.