I saw that someone else provided links to good info. As an anecdotal piece of evidence, I know that big box home improvement places like Home Depot have a dark sky category in their outdoor lighting department. I was flabbergasted the first time I saw that. I would love to see the affect of all homeowners replacing light fixtures with these types of lights. As an example, in the last video I linked earlier today, there are small lights on the horizon that shine very brightly in the video clips. There's one light source in particular that is a single lamp on a pole located on a ranch that is several miles away. If you multiply that by the output of every lamp in a city, it doesn't take a lot of imagination to quickly understand why we can't see the sky at night.