The recent news reported by the New York Times, the BBC and the NPR web sites (for example) as well as in the Iceland Review and Iceland Magazine sites, about the shutting-off of Reykjavik's streetlights in order to better enjoy the Aurora (northern lights), got me thinking.
There are many life-long city dwellers who've never really seen a relatively dark sky or more than a handful of stars. Even people who could do so sometimes have never made the trip out of the city far enough for the experience.
So I was curious if this "lights-out" technique could ever be tried in a city or somewhere else besides in Iceland.
I'd like to estimate how big of a radius of "lights-out" would an observer need for the sky to be noticeably darker. But for that I'd have to know what is actually doing the scattering, and how far up does it extend.
My question: Why (actually) is the night sky so bright in the city? How far up is that happening?
I'm also curious if it is generally stronger in some climates vs others.