Dark skies are being engulfed by light all over the world, creating some unexpected consequences, the Wall Street Journal reports. Over two-thirds of the world's people— including nearly all Americans—can no longer see "what is possibly the most extraordinary natural wonder," said one astronomer. The amount of artificial light worldwide has tripled since 1970, and is suspected of causing some cancers.
Light pollution affects almost all the populated areas of the planet, including those far from big cities, researchers have found. Even in Death Valley, the bright lights of Las Vegas 120 miles away can obscure everything but the moon. A few cities have begun lighting reforms to restore the night sky, shielding streetlights and encouraging the use of low-wattage bulbs. (More star stories.)