Light pollution [View all]

[LiberalArkie]

http://www.pbs.org/seeinginthedark/astronomy-topics/light-pollution.html

(When a massive power outage struck southern California in the 1990s, Los Angeles residents reportedly called 911 to express alarm about strange clouds hovering overhead; they were seeing the Milky Way for the first time.)




Light pollution—the needless shining of bright lights into the night sky—has robbed whole generations of the chance to see nature on its largest scale. It is estimated that as many as eighty percent of all the people alive today have never even glimpsed the Milky Way. (When a massive power outage struck southern California in the 1990s, Los Angeles residents reportedly called 911 to express alarm about strange clouds hovering overhead; they were seeing the Milky Way for the first time.) The problem is not lighting in itself, but the billions of dollars worth of energy wasted each year by spilling light into the sky rather than confining it to the ground where it is needed.



Light pollution has driven professional astronomers to site their observatories on remote islands and mountaintops, while robbing amateur astronomers—and their children—of faint stars and galaxies lost in the glare.
Fortunately, there are solutions that save money and preserve the dark night sky. The most important step is to shield outdoor lighting so it is cast downward. Other measures include putting motion sensors on the security lights that, in so many cases, flood private yards all night; this actually increases security while saving on energy bills. It also helps to limit the specific wavelengths in which the light is emitted.

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