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Light pollution is wasted artificial light; light that shines where it is neither needed nor wanted. Most light fittings waste a large fraction of the light they produce. To put the problem in perspective, estimates place the cost to the US in the neighborhood of $5,000,000,000-$10,000,000,000 annually. That’s $5-10 Billion dollars with a capital “B”. This is not the sum total of all outdoor lighting, this is just that portion of outdoor lighting that is so misdirected as to light up the night sky. This is an incredible sum of money to simply waste, and yet that’s exactly what we do year after year. In fact, the problem is actually increasing in magnitude and cost."
