Light and waves in general have many practical applications. They are used in solar panels to produce electricity, in solar furnaces to produce heat or in image amplifiers to make images more bright at night. Other types of radiation (infrared, UV, X, gamma) are used in astronomy to detect invisible objects or in medicine to …

In a few years, radio astronomers will also have access to a new generation radio telescope, the Square Kilometer Array (Square Kilometer Square or SKA) being built in Australia and South Africa, which should be operational by 2020. Although 10 countries form the core of the SKA, about 100 organizations from twenty countries participate in …

It has been known since the discovery of Heinrich Hertz in 1887 that radio waves are of the same nature as light waves. In particular they propagate in a vacuum in a straight line (geodesic) at a constant speed of 299792.45 km / s. It is by their wavelength (or their frequency) that the hertzian …