Infrared Space Observatory (ISO): final results

Article By:

Cesarsky, Diego A. Institut d'Astrophysique Spatiale, National Center of Scientific Research, Université de Paris Sud, Orsay, France.

Cesarsky, Catherine J. Énergies, Direction des Sciences de la Matière, Saclay, Orme des Merisiers, France.

Last reviewed:2000

DOI:https://doi.org/10.1036/1097-8542.YB000810

The observation of celestial objects at wavelengths ranging from 1 micrometer to several hundred micrometers is known as infrared astronomy. Infrared radiation is that part of the electromagnetic spectrum located between radio waves and visible light. The major contribution of infrared astronomy to the field of astrophysics is the observation of dusty regions and solid bodies too cold to emit visible radiation. Dusty regions not only are invisible to the eye but also absorb the optical light originating behind them; the absorbed light warms up the dust and makes it glow in infrared light. Dusty regions are seen as dark patches in many optical images. Infrared photons are very weakly absorbed by dust, and thus infrared observations reveal what happens inside and behind these obscured regions (Fig. 1).

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