My thought was actually to have multiple projectors per block approximately 10 feet up (building mounted) with sensors to identify people and have them 'place' a smallish ball of light at about 8-10 feet up that floats above and in front of them, but with much less light needed than a 'street light'...and maybe stationary one's in intersections (these could even have 'covers' to stop wasted light from going up). Or, it could project tiny lights (like in the video) near ground level to illuminate the sidewalk, but that's not as useful by far.
By my estimation, there could be less pollution because there would be fewer, smaller lights on at any one time (where normal lights are just ON all night). I agree, there are many issues to solve, but it's doable if thought about thoroughly.
It's a little too late to worry about 'light pollution'...in fact I bet it's not on the average person's radar. Sadly, many people in cities have never seen stars at night and don't have a clue how much is hidden from them. (I live in the boonies of far N cali, and we still have light pollution from nearby towns, but nothing like in a city...I've even watched the international space station get re-supplied while sitting in my hot tub! That was amazing!).

Cutting back on light pollution isn't too hard if lighting and building designers and the like would just care. For highlighting a building, rather than have lights pointing up, put the lights under the eaves pointing down. (I actually don't get why people light up their houses so much, especially if there are street lights nearby as well, that makes that much more light for a thief to have in the house without having to use a flashlight or turn on lights or anything else to give away their activity, plus it just doesn't make sense to me to highlight a house 99.999% of the time) Along the sidewalk of the local shopping center strip, they have these big 3' round lights shining light in all directions, but if they simply capped it, and had a reflector on top to direct light down and around, they could achieve better light distribution for pedestrians for far less energy, a win all the way around for them. Light is still reflected off the ground up, but isn't as intense. Street lights can be made to cause less glare and direct light better, which again saves energy while keeping the light needed for the road just as good if not better. The problem is, those fixtures aren't widely used yet, so they cost more than the normal ones (supply and demand working out there, plus just gouging). I would bet that even a major city could greatly cut their light pollution down without sacrificing safety, and perhaps increasing it, and saving energy with just a few steps. Problem is most people don't know much about it, nor care, save for those of us who would love to have a nice telescope, but find it hard to justify especially when the skies nearby aren't dark enough... Really just need to start modifying zoning laws and restrict accent lighting and do better on street lighting where/when needed (and cutting it when not needed, which is perhaps far more often the case, since it is usually just a security blanket while not providing any security at all)... But yeah, since that isn't likely to happen, not much is likely to happen and those of us wanting to see the night sky in its glory are stuck with long drives...

It would be kinda cool if the sun started shooting out EMPs at us randomly two or three times a week for a few years. Either that, or take a boat ride out to see some 300 miles from any light source at night. Not sure how else you could avoid light pollution now a days.

[redacted]

>> ^Mcboinkens:
To be fair, what has the ISS accomplished? It seems ignorant to ask, and the budget is much, much smaller in comparison, but if we are arguing what spending could be cut, pretty much anything could be a target.


http://www.youtube.com/watch?v=iN-gR9040fw

Because it's what's next. Right now it seems a drowsy step as we tumble into the larger stellar neighborhood, but every step we take away from our cradle ensures that it will not necessarily be our grave. The distances involved seem insurmountable, but so too did the distance between Eurasia and the Americas might have seemed to an ancestor, astride a hollowed out log (and even then, the Polynesians navigated unimaginable distances with tech that was hardly better than that ancestor). We need this as a species. I believe but cannot prove that a greater malaise has infected us as a species due to light pollution. Take a city kid out to a field in the middle of nowhere, and show him the Milky Way in all its glory, and he will gasp in transcendental delight. We no longer see such wonders, except as static images in books and on TV. We do need to feed the masses of humanity, but I believe that an understanding of our place in things makes us more likely to see that we are 'trapped' here, and need to care for our fellow prisoners, and that we will never truly escape unless we all go as one.

http://www.youtube.com/watch?v=bVbnRbTi5XA

>> ^Payback:
0:45 - 0:53 blew me away... coulds acting like waves...
Anyway... how did he photograph stars during the day, or do filters do that for you? I know nothing of photography beyond pressing the middle button on my blackberry...
Pretty sure that was actually footage from night and the bright light source was the moon. The other daytime shots didn't have any stars in them.


I have access to a mile-long lake in the middle of the Canadian forest and the nearest habitation is over the horizon so there's very little light pollution. A friend and I went in once in the middle of our winter, and with the incredible northern constellations like Orion on full display, the stars are almost that bright. I'd love to see what some timelapse exposures would look like in there.

If only we could see the same night sky that our ancestors saw. There is so much light pollution in the world you pretty much need to go to sea to view a perfectly dark sky.

For more information check out the IDA.

Massive spread of light pollution does affect animals, migration patterns, etc. But I won't go into the details here. But.. I am familiar with such issues being involved in Astronomy, optics, etc. A friend is also a president, and physician in a major medical society within the US. They have solid science backing such things and how light pollution can affect people and animals in negative ways.

Sure light pollution can't be rid off 100%. The 9/11 memorial isn't on 24/7 every day, so that isn't a major problem either. We're talking in a practical sense, not in an absolute sense. Most cases of light pollution is quite simple to solve. Use a full cut-off fixture. You can cut down the lumens of the bulb. Saving yourself a great deal in cost for both electricity and the fixture. Rather than blasting wasted watts into the sky, focus it where you need it, Right down the the ground. A rather simple concept really.

If only every state would take it into consideration, it would save taxpayers huge sums of money in public electricity bills. Some states in the US, and some other nations, have adopted such policies/laws and it has shown it's effectiveness. There is often resistance to such change. We always see it from one sector. The lighting industry. They throw a lot of money to prevent states from making sensible decisions to save taxpayers cash. Often presenting bogus science, or no-name experts. Unfortunately for them in our area, we have an army of professors from big name local educational institutions to call upon. Not everyone is so lucky however. Still, it is sometimes hard to bear fruit as politicians tend to be more likely to listen to money before science.

So my point is about light pollution awareness in general. Most people aren't even aware of it, so I took the opportunity to mention it in this context as you can actually see the affect it can happen on wildlife. In the case for the 9/11 monument, I'm not concerned about it. It is a memorial that is not on 24/7. If the lights were, then it certainly could become an issue.

>> ^xxovercastxx:

>> ^honkeytonk73:
.... and light pollution supposedly causes no harm ....

A) Who says that?
B) Where is the harm in this instance? The lights were switched off for 20 minutes 5x to allow the birds to reorient. So, what, we wasted maybe 45 minutes of their time?

>> ^honkeytonk73:

.... and light pollution supposedly causes no harm ....


A) Who says that?
B) Where is the harm in this instance? The lights were switched off for 20 minutes 5x to allow the birds to reorient. So, what, we wasted maybe 45 minutes of their time?

.... and light pollution supposedly causes no harm ....

I see 4 major problems with this...

I see is tires running on a wet glass road. The glass is a lot flatter than asphalt, and so hydroplaning will be far more prevalent unless specific tires were made to cope.

Further, the cost issue will be catastrophic. Solar panels are very, very expensive. Manufacturing solar cells these days is a fairly dirty process, with many very hazardous bi-products. Producing enough solar cells to cover even just major roads would be problematic.

There is also a huge issue of light pollution. Upward facing LEDs replacing road lines is going light up the night sky to absurd degrees, especially in the already light doused cities.

And finally, there is the issue of shifting roads. No matter where you are, soil is always moving. Look outside at the nearest street and see if you can't find a crack due to soil shearing. This will be especially bad in certain geographic locations. Breaking of the roads will require challenging repairs and custom peices to be made. Further, if the roads are replacing power lines as was suggested, power outages would occur as a result of these road breaks, and restoring power will take as long as it takes to fix the road, weeks probably, longer if there is severe damage from natural disasters, earthquakes, etc.

I love the ingenuity, but it is just not practical...

It's really too bad that so many cities suffer from light pollution. It can be difficult to find Andromeda in most cities.

>> ^ant:
What's with the lightings?


I'm not 100% sure what you mean by your question, but as an amateur astronomer (and photographer) I'll take my best guess at what you're asking. Astronomers prefer red lenses in their flashlights for two reasons.

(1) Red flashlights have the least impact on your dark adaptation. It takes nearly an hour of complete darkness for your eyes to FULLY dilate to the point of maximum sensitivity. This dilation greatly enhances your ability to detect extremely faint objects such as galaxies and nebulae. One instant of white light will undo this effect. Red lenses have the least impact on your dark adaptation.

(2) Thanks to light pollution astronomers tend to gather in large groups in the few remaining places where we can actually see the sky. The plethora of red lenses is quite the spectacle. Especially in time lapse.

Hope that helped.

>> ^Abducted:
Hello light pollution.


Looks like HEAVY pollution to me...

Hello light pollution.