Article on how the image was made: http://earthobservatory.nasa.gov/Features/Lights/
from page 2
So at best, take artistic license and just make it "look good".The images were taken by a Defense Meteorological Satellite Program’s (DMSP) Operational Linescan System (OLS). This network of satellites was originally designed to pick up on lunar illumination reflecting off of clouds at night in order to aid nighttime aircraft navigation. What the Air Force discovered is that on evenings when there was a new moon, the satellites were sensitive enough to record the illumination from city lights. Over a period of several new moons, the data the satellites retrieved could be pieced together to produce a global image of city lights.
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The eye doesn't see things the same way the camera does, so you probably don't see the lights just like that (well, definitely not, since at least some would be obscured by weather patterns), but you can see them. People started taking pictures of the Earth's night lights because they could see them. The human eye is very sensitive to light.
http://earthobservatory.nasa.gov/Fea...CitiesAtNight/ may be of interest.