Great post and summary. I feel a bit like a hypocrite commenting here because I live in an extremely light polluted city! Is it wrong to say that it's the city dwellers that are in dire need of starlight, more so than the ones who live under dark skies? If I were to ask my neighbours to switch their lights off-not the nice neighbours who would understand, but the ones I don't know well-I'd likely be met with an extremely hostile reply. In cities especially, I feel people get really defensive about lights, likely because of safety reasons. Which is very understandable! I feel very unsafe walking alone at night and safety (along with more extreme claims re: human health effects) is one of the more contentious topics with regards to dark skies/light pollution. The exception is if it shines directly into their bedrooms at night, and even so, the property owners will say 'get blackout blinds', rather than fixing the problem, or would change the light but it would be even worse and brighter.
I just want to add something re: sky glow. I know that can also get it even if there is no moisture (I'm presuming you mean clouds) in the air and the sky is crystal clear, with little to no air pollution and extremely dry. Any misdirected lights would pollute the sky regardless and make it glow. It's not an atmospheric phenomenon, you would probably get skyglow on the Moon if people ever decide to put artificial lights there!
As far as sky glow on the Moon—because there isn’t an atmosphere, there’s not much for light to reflect off of except for perhaps some loose dust. There is an exosphere on the Moon, which is kind of like gasses that escape from the rock on the Moon itself, but I’m honestly not sure how much that would contribute to sky glow. Maybe?
So, even on a “nice” day/night, there is still moisture in the air as well as other particles that would cause sky glow from the light reflecting off them. It’s more visible to the eye when it’s cloudy, but when i look up from my yard on a “clear” night, the sky still looks red, and when I so astrophotography it’s very evident. Summer is warmer and more pleasant for stargazing, but it’s also more humid, which means it’s harder to take good pictures! Wildfires contribute to that as well. Oddly enough, there are studies that say that brighter lighting doesn’t increase security. On your property, it makes what you have very visible, and the glare can actually HIDE people who are intruders or who might be following you. I think it’s probably a fine balance to find the right amount.
I'm thinking of the driest, least polluted and remote places in the world, like the Atacama, where there's hardly anything in the air to reflect light. They wouldn't have skyglow, correct? That's the reason observatories are built there because of sky clarity and dry air, and also at high altitude because the air is less dense and the seeing is better (it's a bit like being closer to space).
Here in the UK we hardly get proper clear skies, lol...our issue in summer isn't about humidity but long days and long twilights so less time to stargaze. We get more moisture and damp in winter (surrounded on all sides by the sea) though interestingly I've noticed that our night skies are clearest in spring. Which is very pleasant!
I am still dubious about security claims about light and dark. The studies may be true for petty and property-based crime, but for violent crime, different story. A lot of women say they don't walk alone in dark places and that reductions in lighting make them even more scared to go out at night. It also depends a lot on location. In some places I travelled, I felt ok being alone in the dark, but not so in many big cities. I know that the problem of keeping safe in the dark, especially for women, is very complex and nuanced and statistics alone cannot unravel this issue. And it's not darkness itself that's the cause, of course. But it is a big obstacle in resolving light pollution issues in cities. Even to the point that some rather unsavoury political parties are using street lighting and crime as a way of getting votes!
Great post and summary. I feel a bit like a hypocrite commenting here because I live in an extremely light polluted city! Is it wrong to say that it's the city dwellers that are in dire need of starlight, more so than the ones who live under dark skies? If I were to ask my neighbours to switch their lights off-not the nice neighbours who would understand, but the ones I don't know well-I'd likely be met with an extremely hostile reply. In cities especially, I feel people get really defensive about lights, likely because of safety reasons. Which is very understandable! I feel very unsafe walking alone at night and safety (along with more extreme claims re: human health effects) is one of the more contentious topics with regards to dark skies/light pollution. The exception is if it shines directly into their bedrooms at night, and even so, the property owners will say 'get blackout blinds', rather than fixing the problem, or would change the light but it would be even worse and brighter.
I just want to add something re: sky glow. I know that can also get it even if there is no moisture (I'm presuming you mean clouds) in the air and the sky is crystal clear, with little to no air pollution and extremely dry. Any misdirected lights would pollute the sky regardless and make it glow. It's not an atmospheric phenomenon, you would probably get skyglow on the Moon if people ever decide to put artificial lights there!
As far as sky glow on the Moon—because there isn’t an atmosphere, there’s not much for light to reflect off of except for perhaps some loose dust. There is an exosphere on the Moon, which is kind of like gasses that escape from the rock on the Moon itself, but I’m honestly not sure how much that would contribute to sky glow. Maybe?
So, even on a “nice” day/night, there is still moisture in the air as well as other particles that would cause sky glow from the light reflecting off them. It’s more visible to the eye when it’s cloudy, but when i look up from my yard on a “clear” night, the sky still looks red, and when I so astrophotography it’s very evident. Summer is warmer and more pleasant for stargazing, but it’s also more humid, which means it’s harder to take good pictures! Wildfires contribute to that as well. Oddly enough, there are studies that say that brighter lighting doesn’t increase security. On your property, it makes what you have very visible, and the glare can actually HIDE people who are intruders or who might be following you. I think it’s probably a fine balance to find the right amount.
I'm thinking of the driest, least polluted and remote places in the world, like the Atacama, where there's hardly anything in the air to reflect light. They wouldn't have skyglow, correct? That's the reason observatories are built there because of sky clarity and dry air, and also at high altitude because the air is less dense and the seeing is better (it's a bit like being closer to space).
Here in the UK we hardly get proper clear skies, lol...our issue in summer isn't about humidity but long days and long twilights so less time to stargaze. We get more moisture and damp in winter (surrounded on all sides by the sea) though interestingly I've noticed that our night skies are clearest in spring. Which is very pleasant!
I am still dubious about security claims about light and dark. The studies may be true for petty and property-based crime, but for violent crime, different story. A lot of women say they don't walk alone in dark places and that reductions in lighting make them even more scared to go out at night. It also depends a lot on location. In some places I travelled, I felt ok being alone in the dark, but not so in many big cities. I know that the problem of keeping safe in the dark, especially for women, is very complex and nuanced and statistics alone cannot unravel this issue. And it's not darkness itself that's the cause, of course. But it is a big obstacle in resolving light pollution issues in cities. Even to the point that some rather unsavoury political parties are using street lighting and crime as a way of getting votes!
Yeah—Atacama is not only very dry, but they are very, very careful about light there because of the observatories!
And the safety thing is certainly something I’d questioned as well.