111–120 of 146 posts
We drive 2.5 - 3 hours to Abu Dhabi deserts to watch milky way. It is nearly impossible to enjoy dark sky in Dubai.
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Chicago has been slowly replacing its yellow sodium streetlamps with efficient LEDs that project down instead of up. They've been working block-by-block in a systematic way that you can see when you fly into the city at night. It's quite dramatic.
My town replaced the sodium light across the street with a LED. A lot more light comes in the windows now. It sucks.
(Somewhere around Peckham, I've a feeling near Sceaux Gardens, IIRC.)
You'd think they'd do better at containing the light from the grow houses, so more ends up on the plants and less making it to space. Like, foil or something?
Since these are greenhouses they have to be clear to let the light in during the day, I assume. Anything that's going to reflect light to prevent it from leaving at night will also block the sun from hitting the leaves during the day, unless it's a complicated mechanical system that can be folded up during the daytime. I'm guessing such a reliable mechnical system together with maintenance is much more expensive than…
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Those greenhouses are the size of many football fields.. Putting tarps over them is a job that will take many days :) But yeah shutters or something smarter (like two-state glass) should work IMO. I think you even get glass that can switch to mirror mode.
There is research on whether solar arrays would be a net benefit. Those cells would catch most of the sun’s light, turn it into electricity to power the LEDs that have wave lengths that are better matched to what the plants need. A variation of that only catches the sun’s green light and uses it to power pink/red LEDs ( https://www.treehugger.com/solar-technology/solar-smart-gree... )
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The LED and snow issue is about traffic lights, which are horizontal and therefore subject to getting filled with blowing snow. Streetlights face down and don't have a cavity to fill with snow.
It's also FUD, it's trivial to add a heater to the LEDs and still come in at a lower wattage than a tradition lamp.
A lot of fracking sites near me have exceptionally bright lights at night when they're being actively worked on. I suspect the brightness shown might be regular old electric lights, not just gas flares.
Car parks are notorious light polluters as well. These are large parking lots where car manufacturers off load cars by rail for their "last mile" delivery to the area dealerships. The lights are meant to keep the thief away. On top of the horrendous light pollution, they also cause massive* traffic headaches where the trains can come to a complete park for 20-30 minutes while the train cars with autos are connected/d…
I can't figure out one light pollution source in Poland in Sluchowo (54.77550N, 17.94972E). The map from 2015 shows some factory of sorts, but it disappears on the map from 2020, all you can see is an outline what it was. I really wonder what kind of place this was and why it emitted relatively a lot of light.
Most likely some kind of military operation. It could be a storage site, guarded 24/7 where light is important so the guards can see everything clearly.
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Take them off during the daytime. They're not permanent installments.
Those greenhouses are the size of many football fields.. Putting tarps over them is a job that will take many days :) But yeah shutters or something smarter (like two-state glass) should work IMO. I think you even get glass that can switch to mirror mode.
Ah yeah, in the post's first "unknown light pollution" example, I figured it must be a greenhouse. I was driving through a relatively small town one time and was a bit freaked out by this ominous yellow glow off in the distance. Like, the whole sky was glowing [0]. I ended up driving out to try to find the source, and discovered it was a huge greenhouse/farm. Luckily not an extraterrestrial landing zone or so on ;) […
How it looks like from bird's eye view at daytime.
