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The lights that hide the stars

In times of energy rationing to say that towns have too much artificial light might seem to be going against common sense. However, at least in Europe and the United States, there is a movement afoot among astronomers that is defending the dimming of lighting with the argument that it is more and more difficult to discern the sky with its stars and planets at night. According to them, 50% of the people who live in European Union countries and 80% of those who live in the United States, can’t see the Milky Way. Intent on obtaining a precise analysis of the problem, Pierantonio Cinzano, of the University of Pádua in Italy, and his colleagues, have been studying satellite images collected though the Meteorological Satellite Program of the United States’ Air Force during 1996 and 1997. The pictures register light during cloudless nights and the astronomers are using mathematical models to calculate the artificial luminosity of the Earth. It is this work that has resulted in the first global atlas of light pollution, to be published in the Monthly Notices of the Royal Astronomical Society, informs the magazine New Scientist (edition of 18th of August). “Light pollution is growing at 10% per year”, Cinzano says. Not all seems to be lost. For example, Venice is the only Italian city with more than 250,000 of a population where it is possible to see the stars of the Milky Way. “This happens because of the low illumination of the city, something that merits being preserved.”