Astronomers are fed up. One fifth of the world's population cannot see the Milky Way because street lamps and building lights are too bright. So scientists are mounting a new campaign, called Dark Skies Awareness, aiming to reduce light pollution as part of the 2009 International Year of Astronomy.

"Reducing the number of lights on at night could help conserve energy, protect wildlife and benefit human health," astronomer Malcolm Smith of the Cerro Tololo Inter-American Observatory in Chile wrote in a commentary Wednesday in the journal Nature.

Smith points out that billions of dollars of light is needlessly shined into the sky each year. Beyond the waste of money and energy, this light is blocking people's view of the heavens.

"Without a direct view of the stars, mankind is cut off from most of the universe, deprived of any direct sense of its huge scale and our tiny place within it," Smith wrote.