"A radar aboard a sattellite emits electro magnetic radiation in the micro-wave, wave band (emitis micro-wave light radiation) and then receives the reflection from the surface of the earth."
Its just straight ordinary radar Paul, same thing that a bat does with sound. I should just say receives in English. Ever seen your radio jump up an capture the radio waves or go for a walk and collect them? Finally, microwaves are not in the visible range, they are not "light", you can't see them except on a radar screen.

Remote Sensing

* Radar uses microwave radiation to detect the range, speed, and other characteristics of remote objects. Development of radar was accelerated during World War II due to its great military utility. Now radar is widely used for applications such as air traffic control, navigation of ships, and speed limit enforcement.


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Note added at 10 hrs (2008-05-15 05:57:16 GMT)
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http://en.wikipedia.org/wiki/Microwave

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Monica, in English, light is only that part of the spectrum which enters the eye and stimulates the retina, or which Newton considered in his prisms. The rest is just different wave bands of electromagnetic radiation.

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Gather signals, and gather waves yes.

A radar receiver detects and often analyzes the faint echoes produced when radar waves bounce off of distant objects and return to the radar system. The antenna gathers the weak returning radar signals and converts them into an electric current. Because a radar antenna may both transmit and receive signals, the duplexer determines whether the antenna is connected to the receiver or the transmitter. The receiver determines whether the signal should be reported and often does further analysis before sending the results to the display. The display conveys the results to the human operator through a visual display or an audible signal.

http://encarta.msn.com/text_761569568___44/radar.html

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Note added at 13 hrs (2008-05-15 07:58:08 GMT)
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For other uses, see Light (disambiguation).
A beam of white light (entering upwards from the right) is dispersed into its constituent colors by its passage through a prism. The fainter beam of white light exiting to the upper right has been reflected (without dispersion) off the first surface of the prism.
A beam of white light (entering upwards from the right) is dispersed into its constituent colors by its passage through a prism. The fainter beam of white light exiting to the upper right has been reflected (without dispersion) off the first surface of the prism.
Wiki, which I agree with, but qualified:
"Light, or visible light, is electromagnetic radiation of a wavelength that is visible to the human eye (about 400–700 nm). In a scientific context, the word light is sometimes used to refer to the entire electromagnetic spectrum.[1] Light is composed of elementary particles called photon."

The word light is sometimes used to refer to the whole of the electromagnetic spectrum but, I would say only when talking about relativity in English and the "speed of light".


Image of two people in mid-infrared ("thermal") light (false-color)
Image of two people in mid-infrared ("thermal") light (false-color)

For example infrared electromagnetic radiation is often referred to as heat, rather than light. It is just a different use of words.
Wiki again, which I agree with.

Infrared (IR) radiation is electromagnetic radiation whose wavelength is longer than that of visible light, but shorter than that of microwaves. The name means "below red" (from the Latin infra, "below"), red being the color of visible light with the longest wavelength. Infrared radiation has wavelengths between about 750 nm and 1 mm, spanning five orders of magnitude. Humans at normal body temperature can radiate at a wavelength of 10 microns.[1]

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It is common to talk about infrared light and ultraviolet light because they border on the visible spectrum.
However to talk about microwave light is a little unusual.
This guy puts it in inverted commas





Microwave Metrology for Nondestructive Evaluation

Electromagnetic energy propagating at microwave frequencies can be dealt with in many respects in a manner similar to that of visible light. The principal difference between visible light and microwave "light" is that microwave wavelengths can be between 1,000 and 10,000 times longer than the wavelength associated with visible light.




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Note added at 13 hrs (2008-05-15 08:35:54 GMT)
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I wouldn't say "do not count" rather than are not usually referred as by physicist. You can call them "pulses" (impulsi), but again it is more usual to call them "signals" in radar technology. Apparently there's a similar word in German which got translated as "instinct" in the first translations of Freud, which led people to think they were inherited. Nothing to do with light of course.

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http://en.wikipedia.org/wiki/Synthetic_aperture_radar
Fascinating stuff. Remember when I went to see a holograph exhibition at the Royal Academy of ArtLondon when they had just been invented.
I take back what I said about pulses.

Catching the light coming from Earth by reflection of its atmosphere-surface