Atmospheric window
An atmospheric window is a range of wavelengths of the electromagnetic spectrum that can pass through the earth's atmosphere. The optical, infrared and radio windows comprise the three main atmospheric windows. Nomenclature. Some sources, mainly the ones related to the study of the greenhouse effect, suggest a synonymity of the terms "atmospheric window" and "infrared window", due to the fact that the earth's infrared emissions escape into space via this range of wavelengths (8 – 14 μm); in this context, the infrared window is examined as the atmosphere's sole escape route of heat, exclusively described as  the atmospheric window. This terminological ambiguity is not present in other fields of science and technology, namely radio astronomy and remote sensing. Scientific importance. The atmospheric windows, especially the optical and infrared, play a vital role in the sustainability of life on Earth, regulating the earth-atmosphere energy balance. They are utilised for observational and telecommunicational purposes and closely studied by environmental scientists. In astronomy. Up until the 1940s, astronomers used optical telescopes to observe distant astronomical objects whose radiation reached the earth through the optical window. After that time, the development of radio telescopes gave rise to the more  successful field of radio astronomy that is based on the analysis of observations made through the radio window. In telecommunications. Communications satellites greatly depend on the atmospheric windows for the transmission and reception of signals: the satellite-ground links are established at frequencies that fall within the spectra of atmospheric windows. In remote sensing. Both active (signal emitted by satellite or aircraft, reflection detected by sensor) and passive (reflection of sunlight detected by the sensor) remote sensing techniques work with wavelength ranges contained in the atmospheric windows' spectra.