Light pollution is drowning out the stars

The Atlantic : As the world population grows, so, too, does the amount of artificial light from street lamps and other types of outside lighting. As a result, some 99% of North Americans and Europeans now experience a perpetual glow of artificial light at night, and about one-third of all people on Earth can no longer see the Milky Way. Those findings are based on a new dark-sky atlas created from sky-glow satellite data. Researchers say part of the problem is the increasing use of cool-white LEDs, which, because they use less energy and shine more brightly, are replacing the older sodium and metal halide street lamps. One solution is to switch to warm-light LEDs, which are not as bright. Also, downward-directed lamps with better shielding would help minimize the spread of light. Not only should the night sky be protected because it is a valuable natural resource, the researchers say, but some animals depend on moonlight and starlight to navigate and perform other activities.