By Flavio Falcinelli
Radio astronomy studies the sky by analyzing the natural radio waves emitted by celestial objects: any object, if not only for its temperature, radiates measurable electromagnetic waves which generally show the incoherent characteristics of a broad spectrum noise.
In general, by radio source is indicated any source of radio waves: in common use the term has become synonymous with the cosmic sources of radio waves.
Radio telescopes, instruments that record the faint radio stream coming from outer space, include an antenna system, transmission lines and a receiver: the electronics amplifies the signal received by the antenna to make it measurable. There follow the devices for processing and recording of the information, in addition to organs for the instrument control and the antenna direction.