Portion of the electromagnetic spectrum that is situated between radio waves and infrared radiation. Microwaves have wavelengths ranging from 30 cm to 1 mm, corresponding to frequencies from about 1 gigahertz (109 Hz) to 1 terahertz (1012 Hz). They are the principal carriers of television, telephone, and data transmissions between stations on Earth and between the Earth and satellites. Radar beams are short pulses of microwaves used to locate ships and planes, track weather systems, and determine the speeds of moving objects. Microwaves are absorbed by water and fat in foodstuffs and produce heat from the inside (see microwave oven). Materials such as glass and ceramics do not absorb microwaves, and metals reflect them. See also maser.
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