Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Making War On Light Pollution 437

Hugh Pickens writes "Almost thirty years ago I worked in the Middle East helping install a nationwide communications system and had the opportunity to be part of a team doing microwave link tests across Saudi Arabia's Empty Quarter. Something I've never forgotten were the astonishing nights I spent in the desert hundreds of miles from the nearest city where the absence of light made looking at the sky on a moonless night feel like you were floating in the middle of the galaxy. In Galileo's time, nighttime skies all over the world would have merited the darkest Bortle ranking, Class 1. Today, the sky above New York City is Class 9 and American suburban skies are typically Class 5, 6, or 7. The very darkest places in the continental United States today are almost never darker than Class 2, and are increasingly threatened. Read a story from the New Yorker on what we have lost to light pollution and how some cities are adopting outdoor lighting standards to save the darkness."
This discussion has been archived. No new comments can be posted.

Making War On Light Pollution

Comments Filter:
  • San Jose (Score:3, Informative)

    by doxology ( 636469 ) <cozzyd@@@mit...edu> on Saturday September 08, 2007 @06:30PM (#20523759) Homepage
    In San Jose, all the white streetlamps were replaced with low pressure Sodium lamps so that light pollution would not impact research at nearby Lick Observatory [wikipedia.org] so much. Not only are they not as bright, but (more importantly) they're monochromatic and can easily be filtered. If more cities adopted these, we'd be able to see the stars much better (with the right optical filter, of course).

    Unfortunately, a lot of citizens of San Jose want white lights for some reason (especially car dealerships), so I don't know how much longer that'll last.

  • A 20 year old fight. (Score:4, Informative)

    by scattol ( 577179 ) on Saturday September 08, 2007 @06:37PM (#20523817)
    Tucson AZ has been fighting light pollution for more than 20 years. This isn't exactly a new fight. That said, it's gaining momentum. In part thanks to the IDA [darksky.org]. That having been said, this won't be won until the general population sees light pollution as a bad thing. We aren't there yet but with more general public articles there are chances that light pollution becomes as well known as air and water pollution.

    For what it's worth, some estimate that there are about 700,000 amateur astronomers in the US. It's not a huge number. But it's much bigger than the just a few geeks that some would make you think.

    It's a good fight and it starts at home, you can do your part by turning off the exterior lights of your house when you don't need them. With 2009 the international year of astronomy [astronomy2009.org], if you help now, maybe we all will get a better view of the night sky to celebrate the 400 years of telescope observing of the night sky.
  • by Anonymous Coward on Saturday September 08, 2007 @06:41PM (#20523841)
    If you would RTFA instead of rushing for first post you'd see that it mentions that, when properly done, reducing the excessive and inappropriately strong lighting that covers most cities would actually aid nighttime vision by eliminating the glare.
  • Re:I live in Belgium (Score:2, Informative)

    by Anonymous Coward on Saturday September 08, 2007 @07:08PM (#20524021)
    For those who don't know what he's referring to: Belgium illuminates its highways at night.
  • Re:Women want light (Score:5, Informative)

    by J. T. MacLeod ( 111094 ) on Saturday September 08, 2007 @07:23PM (#20524127)
    Those of us from "out in the country" have a different perspective.

    Most nights, it's easier to see in the absence of artificial light, because our eyes adapt to the more complete light coverage provided by the moon and stars. City and suburb folks have problems with darkness because of the incomplete coverage of the artificial lights causes ordinary darkness to appear pitch black, and creates shadows causing even more darkness.

    Driving at night, I generally prefer to be out in the middle of nowhere, because I can see better with my headlights being the only light source.
  • Re:Women want light (Score:5, Informative)

    by Original Replica ( 908688 ) on Saturday September 08, 2007 @07:26PM (#20524135) Journal
    many women demand more lighting during the night, for reasons of safety.

    They may be saying "more" light but they probably mean "more even" lighting. You could see better down a street or across a parking lot if it had half the brightness but it was evenly spread, vs intermittent very bright spots. So having it bright as the noon day sun in front of the bar actually makes it worse to walk across the parking lot, unless that is just as bright. If you have every been out in the country at night and you could see moderately well with a full moon (enough to play soccer, I've done it) that was what even lighting at about 0.035 foot-candles gives you as far as visibility. Most streetlights give you about .7 foot-candles, around 20X the brightness when you are right under the streetlight, but how far outside of the immediate scope of the streetlight can you see? The brighter the bright spots get, the higher the contrast and the less overall visibility you have. My point is that if you keep the brightness low, but take care to light up the dark shadowy spots as well, you can actually see better. Well lit shouldn't be confused with "brighter".
  • Re:It's true (Score:5, Informative)

    by CoralCain2002 ( 592657 ) on Saturday September 08, 2007 @07:43PM (#20524263)
    I have a friend who lives in Park City, UT who got fed up enough with the local light pollution that he decided to do something about it. He founded a company that only sells dark sky friendly lights. Its called Starry Night Lights http://www.starrynightlights.com/ [starrynightlights.com]. Check it out if you really want to do your part.
  • Re:"Pollution"? (Score:3, Informative)

    by UserGoogol ( 623581 ) on Saturday September 08, 2007 @09:05PM (#20524827)
    There's nothing in the word contamination which implies the contamination is permanent. It just means (American Heritage Dictionary, which is a different dictionary, but whatever) "To make impure or unclean by contact or mixture" if excess light is shining in some area, then there is stuff mixed in with it (photons of whatever energy visible light has) that would not otherwise be there, thus it is contaminated. Just because you can turn the lights off and the photons will automatically dissipate seems irrelevant.
  • Re:It's true (Score:5, Informative)

    by Polumna ( 1141165 ) on Saturday September 08, 2007 @09:11PM (#20524873)

    ... but that would inevitably just lead to an increase in crime for that night, so... darn.
    Actually, I read an article in Sky & Telescope (I think... might have been Astronomy) a year or so ago that addressed this. They cited studies that suggested that lighting areas has no effect on crime, but rather on the perception of safety. Consequently, (this is purely my conjecture) using fewer lights may just make people be more careful because they feel endangered, thus having a net reduction in crime, as well as making the sky a prettier place.
  • by mosb1000 ( 710161 ) <mosb1000@mac.com> on Saturday September 08, 2007 @09:28PM (#20524961)
    The object of security lighting is to bathe otherwise dark places in light so that criminals will not feel secure in their ability to commit crime unseen.

    "Nobody's suggesting we get rid of streetlights, by the way: just make them illuminate straight downwards."

    Streetlights already employ reflectors to direct their light downward, they just let it arc over many degrees so that fewer lights will need to be installed, and so that some lights can be turned off to cool while not leaving the street dark. I think they're talking about installing a larger number of smaller lights. I don't know that that would be a worthwhile investment (and it wouldn't reduce the wattage installed in lit parking-lots).
  • crime (Score:5, Informative)

    by falconwolf ( 725481 ) <falconsoaring_2000 AT yahoo DOT com> on Saturday September 08, 2007 @09:40PM (#20525033)

    I always thought it would be nice if we had one day a year where people made a conscious effort to turn off all their lights, like "Star's Day" or some other stupid name so people could have one night a year to keep lights off, but that would inevitably just lead to an increase in crime for that night, so... darn.

    Not really, criminals need light too. And as TFA says when San Antonio started turning lights off at night at schools vandalism went down not up.

  • Re:It's true (Score:2, Informative)

    by wamerocity ( 1106155 ) on Saturday September 08, 2007 @10:10PM (#20525203) Journal
    You'd think so. It would seem dark, but only by comparison. Provo is a pretty big city still, and there are plenty of lights on at night (especially if there is a game going on at Lavell Edwards Stadium). The guy in the article said that even being 150 miles away from Las Vegas near the opposite end of the Grand Canyon still isn't that dark because of the lights, even though they are far away. Although there is a difference, probably on 1 or 2 orders of magnitude, between Provo and Vegas. Wahweap marina at Powell is still the best, IMHO.
  • Re:Women want light (Score:3, Informative)

    by Telvin_3d ( 855514 ) on Saturday September 08, 2007 @10:55PM (#20525465)
    Yes. Done wrong, more lights can make for a more dangerous environment. If you read the article, part of what it touches on is the fact that poorly designed and placed 'bright' lights actually reduce viability. Properly designed and placed lights would reduce light pollution, save electricity AND make for a more secure environment.
  • by Entropius ( 188861 ) on Saturday September 08, 2007 @11:35PM (#20525653)
    -1, Wrong and Uninformed

    People walking at night *do* experience glare. First off, lots of folks wear glasses. Secondly, the presence of streetlights, even assuming no stray reflections, *does* affect human vision by preventing the eye from becoming fully dark-adapted. Many lighting schemes actually make things worse by creating very uneven lighting patterns. The eye will wind up adjusting its levels based on those bright areas, and then be completely unable to see in the dark areas.

    Naturally, anyone up to no good will be in those shadows where nobody can see, because their eyes are metering for the bright areas.

    *Contrast*, not the absolute amount of light, is the real limiting factor here. Two examples:

    I was out in the forest today and saw a bird land on a tree branch west of me, backlit by the setting sun. I couldn't tell what it was; it appeared completely black to me because my eyes were adjusted to the huge amount of light coming from the western sky. I can, however, override my camera's automatic exposure setting, and was able to get a picture (at ISO 100, fyi). There was plenty of light to see by, there was just too much light coming from what I didn't want to see. Your eyes don't have an exposure override.

    You can also see quite well in a whole hell of a lot less light than you think. I've been in situations where moonlight is actually bright enough to be dazzling (compared to the previous starlight when the moon was obscured); starlight is even enough to see where you're going by.

    Starlight is 512 times dimmer than a streetlit street; moonlight is 64 times dimmer. (Reference: http://www.photokaboom.com/photography/learn/tips/ 054b_exposure_light_and_exposure_values.htm#Light [photokaboom.com]) You can see with a lot less light than you think you can, if you'd just turn out the damn lights.

    Also, studies have been done that show that, when streetlights are removed from neighborhoods, crime actually goes down. Why? Because there are no shadows to hide in, and, if it's really that dark, the boogeyman (who's much less common than you think) won't be able to see you either without a flashlight. My neighborhood is unlit and is in a city with a pretty high crime rate (Tucson, Arizona); I've never felt unsafe because of the lack of streetlights.

    Benefits of turning off the lights, since you asked:

    1) It saves power. Gobs of power.
    2) People can enjoy the natural world, and possibly learn something in the process.
    3) Less damn glare, helps drivers and walkers (who can see just fine by moonlight/starlight
    4) Astronomy.
    5) It has been hinted at that excessive artificial lighting at night screws up people's circadian rhythms and might be responsible for certain sleep disorders, fatigue, depression, etc. This hasn't been shown conclusively yet, of course, and in any case looking at a 14" LCD like I am now is far worse.
  • by arminw ( 717974 ) on Sunday September 09, 2007 @12:06AM (#20525817)
    .....You can't imagine what it's like until you've seen it for yourself......

    You can still see that, or at least something close, in a planetarium. The next best thing, if you have a computer, you can download some software for free at:


    Besides viewing the computer screen, this software will also allow you you to set up a planetarium if you have a projector and can rig up a dome shaped screen. It will also control certain telescope mounts.

    It's not likely that the skies over any large city will ever be the way Galileo saw them, long before the invention of electric power generators and electric lights.

    We live in southern Oregon, near the coast and do get to see a full starry sky. The Milky Way and all the stars stand out against a black sky. The glow from Medford, about 45 miles away is mostly blocked by the Mountains.

    The eclipse of the moon on August 28 was also a special treat for which we got up at 2AM. Living in the city has its benefits and drawbacks and so does living in the countryside. Most people are not able to earn a living in the country and must live in brightly lit cities.
  • by TapeCutter ( 624760 ) on Sunday September 09, 2007 @12:06AM (#20525821) Journal
    That would indicate that nowhere on Earth could you get a "darkness" that existed in the 50's and I find that kinda hard to belive since particulate pollution in the form of sulphur and soot was worse then than it is now and as another post pointed out has little affect at high altitude. Also I assume if he flew planes in the 50's your dad is now a passenger and (besides the double glazing) the inside of a modern commercial jet is probably a lot brighter than the cockpit of a B49.

    Speaking as someone who grew up in the 60's in the rural outskirts of Melbourne Australia (40-50Km east of the city center) there were few street lights and the sky at night was nothing less than brilliant, patches of stars so numerous and intesnse they looked like small thin clouds. In the early 70's a faint glow appeared in the west (like twilight was refusing to end), now the city has grown upwards and outwards, "twilight" is permenent, the market gardens where I grew up have been replaced with houses, factories and shopping malls.

    I now live on the beach (much cleaner than it was in the 70's), it's ~20Km south-east of the city center. The shit farm still operates but long ago stopped pumping turds directly into the ocean and now pumps out clean water that has restored the wetlands into a haven for water birds. Sitting between the ocean on one side and a large strip of wetlands on the other I can still easily make out the planets and the main contellations, on an clear night after a storm the milky way and the seven sisters are visable away from street/house lights. But to get the same sort of view I had from my back yard when I was a kid requires a two hour drive in order to put a mountains range between me and the permenent twilight. In other words, the "primeval sky" (best viewed with a young naked eye) is still there, but these days I really have to go out of my way to find it.
  • by Anonymous Coward on Sunday September 09, 2007 @12:33AM (#20525973)
    This tool will tell you about the nearest dark skies: The Dark Sky Finder [darksky.org]. The tough part is finding a place to park. This tool will just drop you in the middle of nowhere. It might be easier just to find a star party [skyandtelescope.com] near where you live.
  • Re:Ascension Island (Score:4, Informative)

    by Suddenly_Dead ( 656421 ) on Sunday September 09, 2007 @01:16AM (#20526183)
    The Orion Nebula and Andromeda Galaxy are easily visible in half-decent skies. Just because people didn't know what they were doesn't mean they couldn't see them.
  • by Gary W. Longsine ( 124661 ) on Sunday September 09, 2007 @01:56AM (#20526355) Homepage Journal
    A quick Google search shows that there seem to be studies about lighting and crime. Sure the topic probably merits additional study, but discounting the work that has been done based on an unsourced sentence leading a wikipedia article probably isn't helping further the discussion.

    Here are a couple papers which each include several references:


    I'm all in favor of a darker sky, but we are not going to win many converts if we keep lying about something that can be so trivially debunked.
  • Re:San Jose (Score:4, Informative)

    by Alioth ( 221270 ) <no@spam> on Sunday September 09, 2007 @04:57AM (#20527061) Journal
    Low pressure sodium lights are also much more efficient - they are the most efficient lights we have. Added to that they emit light at the wavelengths that human vision is most sensitive, boosting their effective efficiency since you need fewer watts still for the same apparent brightness. No other lighting comes even close to low pressure sodium (SOX) for efficiency. High pressure sodium (SON) is the nearest, but IIRC only has 2/3rds of the efficiency.
  • Re:It's true (Score:1, Informative)

    by Anonymous Coward on Sunday September 09, 2007 @09:40AM (#20528089)
    So much of this problem could be solved by simply converting all those millions of generic cobrahead streetlight fixtures with drop-lens diffusers to flat-lens full-cutoff fixtures. So much of the light gets pumped sideways and up (especially the ones with lenses that drop lower) that it's a huge waste of electricity. You have to use a higher-wattage bulb to light the roadway beneath as you would with a flat-lens cutoff because of the upward light loss...flat-lens diffusers are transparent panes of glass instead of frosted plastic, so the reflectors inside the lamp that are designed to focus light downward can work at max efficiency. Yes, you have to space them closer to get equivalent light (although one every damn pole is already overkill), but if you can get the same light beneath a full cutoff fixture from a 50-watt high-pressure sodium bulb as you would from a 100-watt with one of those exaggerated ball-shaped diffusers then you've saved electricity as well as light pollution. And you've also improved road safety by getting rid of those glare bombs every 50 feet that distract drivers and ruin night vision rather than doing what they're supposed to do...light the @#$% roadway. Framing light pollution as a utopian astronomy issue totally misses the most important dimensions of it.

    Arlington, MA, near where I live, just replaced every 1950's-era drop-lens mercury vapor light fixture in town with high-pressure sodium fixtures, as most towns have in the last 25 years for energy efficiency and lower maintenance costs. But they opted to go entirely with full cutoffs and strictly regulated wattage guidelines depending on whether it's a residential side street or thoroughfare. The ones on side streets are 50-watters, down from 250-watters that were there previously, and give the exact same amount of light on the roadway and sidewalks while being virtually invisible sideways. I believe the arterial roads went from 400-watters to 250-watters and smaller thru streets from 250 to 100-150 watts. Since Arlington's only 2+ miles from Boston and densely populated the fixtures were already situated overkill on every pole, so there was no need to even add new fixtures. That's an assload of electricity saved, no more glare pouring through 2nd-floor windows ruining people's sleep, easier driving because you can actually see objects on the roadways, and no more illumination of trees screwing with birds or getting insects going crazy at night. The only upward reflection you get is off the actual roadway, which being asphalt isn't very reflective...so it makes a huge difference. Flying into Logan Airport your flight path will take you over severall towns that went full-cutoff, and you can see the difference it makes from above with only soft illumination off the actual roadway seen from the sky as opposed to towns that still use drop-diffusers where you can see the sharp points of light coming off the actual fixtures (the City of Boston, which still uses awful oversize 1960's-era power-sucking fixtures everywhere, looks like its roads are lined with thousands of birthday candles from above).

    This isn't an expensive fix. Since most places already have HPS fixtures, you just swap out those ugly drop diffusers on the existing fixtures with the flat lenses, replace the bulbs with appropriately lower wattage, and get each state highway department and city public works department to adopt consistent wattage/placement/spacing guidelines for type of road, traffic load, intersections, etc. instead of slapping the fixtures around willy-nilly like they did previously. All cobrahead fixtures are standard size, the lenses are probably $5 each bought in bulk + labor, and in cities with enough fixtures they usually change all bulbs on a regular schedule of 5 years or so to offset the labor costs of letting all bulbs run out their natural lifespans and having to do too many one-off runs with the truck to change individual fixtures. Problem is as long as utilities charge municipalities per fixture instead of per electricity usa
  • Re:Women want light (Score:3, Informative)

    by pimpimpim ( 811140 ) on Sunday September 09, 2007 @10:51AM (#20528403)
    I come originally from the Netherlands, which is probably one of the most lighted countries in the world. When I visit my family, I am amazed that at night with the curtains open it is as if it is day 24 hours a day. And this is not in a city center, just in a normal housing area. I now live in Germany, not so far away either geographically or culturally, but there is way less light out here, I would say less than half, and I can actually see the stars more often. Still I feel less scared than in the Netherlands, but that is because Germany really is the country of mostly law-abiding citizens the prejudice tells it to be. Most crimes are probably standardized according to some crime industry norm. Just joking...

    On the Autobahns, there are almost no lights at all. In whole west Germany I only know about one or two pieces of a few kilometers where there are lights. And when I first came here I was surprised that driving on an Autobahn with no lights is actually more comfortable than driving on the completely illuminated Dutch roads. You can look much further ahead (an eye trained to the dark can distinguish a single photon, you can probably catch the light of a car that is a mile in front of you) . Also by the shape of the lights you can distinguish trucks from cars, which helps when you're speeding. In general, you can just concentrate better.

    What I don't like BTW are the LED back lights on cars. For some reason they create a memory effect in my retina, and the eyes seem to automatically follow these lights, which is very distracting. This is probably because they have the overall same intensity as normal back lights, but much more focused. I wonder if this isn't dangerous on the long term.

"In matrimony, to hesitate is sometimes to be saved." -- Butler