index: the radio window index: the radio window all colours of the sky

The Radio "window"

Earth receives information from the universe in the form of cosmic raysglossary, neutrinosglossary and above all electromagnetic waves glossary, with wavelengths ranging from radio waves (m – mm) to gamma rays (approximately 10-7 mm).

Fig. 1: Windows opening onto the cosmos.

 

Only a small part of this vast range of radiations can be observed from earth.  Most is absorbed by the atmosphere, which leaves us only two windows opening onto the cosmos:

"The optical window" – studied since the dawn of time

"The radio window" – studied only for the past few decades thanks to the new science:

 

radio astronomy

Fig. 2: The earth's atmosphere completely absorbs x-ray, gamma ray and ultraviolet radiations, which can therefore be observed only by satellite. Visible light, on the other hand, reaches the earth's surface but the best places for optical observations are the top of high mountains, where the atmosphere is more transparent.  These are also the only places from which we can observe the infrared light of  astronomical objects.  Radio waves, which reach the earth without being absorbed, allow us to increase our knowledge of the universe.

The Webweavers: Last modified Tue, 20 Jul 2005 10:01:01 GMT