"Red is the new Black"

March 8, 2013 7:43 AM

Why Is The Night Sky Turning Red?
posted by the man of twists and turns (55 comments total)

So youre saying shining orange sodium vapor lights everywhere makes things look orange?
posted by nathancaswell at 7:49 AM on March 8 [3 favorites]

It wasn't until I read the description of unreal Pepto-bismal pink city night sky in Middlesex did I realize " oh wait, having nighttime be a pale glowing sky of reflected light is actually not just how nighttime looks."
posted by The Whelk at 7:51 AM on March 8

I do astrophotography from an urban area. A typical single frame looks like this. The sky really is very orange. I still get pretty good results after working with many exposures in software, but it really is pretty ridiculous nonetheless and it wouldn't be that hard to improve things a lot as described in that article.
posted by edd at 7:52 AM on March 8 [7 favorites]

Hmm, so we'll replace the hellish orange glow that has made Mordors of all our nighttime cityscapes with an icy blue LED glow? The globe will warm and the skies will chill. . .
posted by DrMew at 7:54 AM on March 8

I thought it had something to do with the return of Azor Ahai, or maybe the rise of House Lannister.
posted by COBRA! at 7:54 AM on March 8 [6 favorites]

Since the human eye sees green so efficiently, I've often wondered if it wouldn't be worth installing green streetlights at a lower power output. We might be able to see better with less light pollution.

The downside, of course, is that it would really screw up people trying to identify controlled intersections, and it'll make everything look like we lived in the Matrix.
posted by quin at 8:00 AM on March 8 [3 favorites]

Bright Eyes - Light Pollution.
posted by Fizz at 8:11 AM on March 8

Dark skies really are a wonderful thing to have. Sometimes when I'm walking home at night, I'll round a corner, look up, and see Orion standing before me a billion miles tall. There's no better lightshow than a starry night. It's sad to think that many grow up without ever seeing it, or even knowing that it is there to see.
posted by Jehan at 8:12 AM on March 8 [12 favorites]

McDonald Observatories' Dark Skies Initiative.
posted by Devils Rancher at 8:13 AM on March 8 [2 favorites]

In my hometown in Northern Italy they've started mandating downward facing LED street lights. It has helped enormously, I wish we could start implementing something like this in the US as well.

My pet theory, though, which is definitely shaped by my passion for archeoastronomy, is that what the world needs is a good, hard dose of the night sky. We need to see the stars to know just how small we are.
posted by lydhre at 8:16 AM on March 8 [10 favorites]

I do astrophotography from an urban area.

Your flickr photostream is excellent!
posted by the quidnunc kid at 8:26 AM on March 8 [2 favorites]

When you are flying at night and you look down to see a hundred thousand lights in a city, remember every light you see is one that is casting its light uselessly upward.
posted by ricochet biscuit at 8:27 AM on March 8 [1 favorite]

When you are flying at night

A witch! BURN HIM OR HER AS THE CASE MAY BE!
posted by the quidnunc kid at 8:29 AM on March 8 [12 favorites]

Map of light pollution in the US.
posted by scottatdrake at 8:31 AM on March 8 [5 favorites]

When you are flying at night and you look down to see a hundred thousand lights in a city, remember every light you see is one that is casting its light uselessly upward.

Not if you're flying over North Korea. Light pollution is just another result of the fact that given the choice, most people prefer the benefits of electricity.
posted by three blind mice at 8:33 AM on March 8 [1 favorite]

quin: that's what low-pressure sodium discharge lamps are designed to do. They produce virtually all of their light output in a double peak at 589.0 and 589.6 nm; this is yellow to our eyes, where green would be more like 530-560 nm, but it's still pretty darn close to our eyes' peak sensitivity. This makes them one of the most efficient light sources available.

There's a law on the island of Hawaii requiring that all outdoor light fixtures use low-pressure sodium, because the narrow peak is relatively easy for the observatories to filter out.
posted by Mars Saxman at 8:36 AM on March 8 [4 favorites]

No, three blind mice, it's a result of carelessly using electricity. Legislation to force cities and private citizens to ensure that street lights point downward is the responsible thing to do, for example.
posted by lydhre at 8:36 AM on March 8 [6 favorites]

lydhre: legislation or no, the problem seems likely to solve itself as we switch over to LEDs, which are highly directional by nature - you have to do extra work with diffusers and reflectors to get the light to scatter. The LED street lights the city installed along my street last year are just flat panels of emitters pointed straight downward; I don't know whether reducing light pollution was one of their goals but it's certainly going to be one of the effects.
posted by Mars Saxman at 8:43 AM on March 8

...Orion standing before me a billion miles tall.

Out of curiosity, I started doing the math to figure out how wrong this was. One light year is 6 trillion miles. So even if the real distance between the top and bottom of Orion is only a single light year (which is not even remotely plausible), the above measurement would nearly 1% of 1% of the real height.
posted by DU at 8:45 AM on March 8 [8 favorites]

I guess my point is: Space is Huge. Hugely huge.
posted by DU at 8:47 AM on March 8 [2 favorites]

I miss the big starry nights that I had as a kid growing up in the country. Better legislation would result in less light pollution and less wasted energy.
posted by arcticseal at 8:53 AM on March 8

Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.--

Hitchhiker's Guide to the Galaxy
posted by Pater Aletheias at 8:54 AM on March 8 [9 favorites]

All I know is if we change it back, there's gonna be some disappointed sailors.
posted by Strange Interlude at 8:58 AM on March 8 [2 favorites]

Red skies at night
posted by TedW at 9:09 AM on March 8

So even if the real distance between the top and bottom of Orion is only a single light year

It's worse than that still, as the stars are vastly different distances from earth; so while it's possible to measure the actual distance between the stars in Orion, it's pretty meaningless as to its actual appearance. A better measure would be the greatest angular distance spanned between a pair of stars in Orion as seen from earth, or perhaps the solid angle subtended by the entire constellation, but that can't be converted directly to a distance or area, respectively, unless you posit some celestial sphere at a completely arbitrary distance.

(As a poetic image, I'm fine with "a billion miles tall." But if you're going to try to make an actual measurement, as DU seems to want to, you ought to acknowledge that the linear distance is not particularly indicative of how far apart they appear in the sky.)
posted by DevilsAdvocate at 9:21 AM on March 8 [2 favorites]

...that can't be converted directly to a distance or area, respectively, unless you posit some celestial sphere at a completely arbitrary distance.

Not completely arbitrary. You could choose the mean distance of the stars that make up Orion to measure Orion's "height". But once I realized how many orders of magnitude the error of "a billion miles tall" was, I stopped caring about find details like that.
posted by DU at 9:32 AM on March 8

There's a law on the island of Hawaii requiring that all outdoor light fixtures use low-pressure sodium, because the narrow peak is relatively easy for the observatories to filter out.

Same in San Jose, CA, for Lick Observatory. That particular shade of yellow happens to be the exact same as a yellow traffic light. A couple times while approaching an intersection at night I've thought a street lamp was actually the traffic signal turning yellow. Oops!
posted by zsazsa at 9:33 AM on March 8

MetaFilter: Out of curiosity, I started doing the math to figure out how wrong this was.
posted by ricochet biscuit at 9:43 AM on March 8 [13 favorites]

Since the human eye sees green so efficiently, I've often wondered if it wouldn't be worth installing green streetlights at a lower power output. We might be able to see better with less light pollution.

Mercury vapor lights are basically green.
posted by nathancaswell at 9:45 AM on March 8

I live in Greater LA in a quieter, relatively "dark" pocket of the valley. I've noticed I can sit outside in the middle of the night and read without any lights on if the sky is overcast at least 50%. The light reflecting from the clouds is enough. Pretty crazy.
posted by Hairy Lobster at 10:09 AM on March 8 [1 favorite]

Intellectually, I know that light pollution is a BAD THING. However, I have yet to shed my romantic feelings for certain bright, hazy urban settings.

I grew up in Las Vegas. Stars may be diamonds in the sky, but my city was dazzling in rhinestones and glitter. To my child eyes, the lights looked like a pirate's chest of gold coins and precious gems had been spilled across the valley floor, sparkling and shimmering during sweltering summer nights. Driving back from vacations, glowing pink-orange clouds would welcome you home over 100 miles away.

Deep, dark nights and a sky full of stars is as foreign to me as lush forests and water that actually belongs on the ground. Experiencing the "real" way that the night sky is supposed to be viewed is amazing, but it is somehow fitting that an unreal place like Las Vegas also has an unreal night.

Hmm, so we'll replace the hellish orange glow that has made Mordors of all our nighttime cityscapes with an icy blue LED glow?

My current city did this and it was a jarring transition. All street lights have been converted to LED in an effort to reduce the city's electricity costs. Even if the 10-yr estimates are only a fraction of the final amount, it will be a significant savings.

Cost-savings aside, I still notice the difference after more than a year. I'm not sure if my objections are real or imagined, but our new blue-ish lights feel brighter but also less illuminating. I'm also curious if they may be affecting sleeping patterns.
posted by Vysharra at 10:17 AM on March 8 [3 favorites]

Out of curiosity, I started doing the math to figure out how wrong this was. One light year is 6 trillion miles. So even if the real distance between the top and bottom of Orion is only a single light year (which is not even remotely plausible), the above measurement would nearly 1% of 1% of the real height.

I was going to just say "million" as some big number, but thought that it was far too small and upped it to "billion". Now that I'm looking, it seems a billion miles would only get us to a little beyond Saturn, and even a trillion miles only to somewhere in the Oort cloud. The nearest star to us, Proxima Centauri, is about 25 trillion miles away. So I guess the farness from the top to the bottom of Orion must be at least the best part of a quadrillion miles.

That said, Orion is still a masterwork of our galaxy and so, so impressive to see towering above you.
posted by Jehan at 10:25 AM on March 8 [1 favorite]

I live 12.5 KMs from the nearest town. When we moved here it was very dark. You could see a very slight light "bubble" on cloudy days. Then Big box stores moved in and a GM Dealership renovated... NOW you can actually tell the difference the bubble is bigger and "drowns" out the sky in that direction. We are moving soon and this is one factor of that decision. Also, another reason to hate on these companies. "Do you really NEED an empty parking lot blazed like noon even at 2AM?".
posted by mrgroweler at 10:28 AM on March 8

You might like to use the poorly defined but expressive "gazillion".

Quite agree about Orion being majestic of course.
posted by edd at 10:30 AM on March 8

In case anyone is interested, here are instructions on how to make a 3-D model of Orion
posted by TedW at 10:32 AM on March 8 [1 favorite]

From my location six miles due east of the Diablo Canyon Nuclear Power Plant, it's "Red skies at night, sailors delight; green skies at night, nuclear engineers call your office."
posted by oneswellfoop at 10:44 AM on March 8 [6 favorites]

One of the most stunning night skies I ever saw was a clear, cloudless and moonless night off the Delaware coast. We were motoring, and I lay on the deck, listening to the throb of the diesel engine and staring up at the bowl of the Heavens above. The stars, the planets, the Milky Way, the endless endless dots of light across an inky sky.
posted by the man of twists and turns at 11:17 AM on March 8 [1 favorite]

Pater Aletheias : Hitchhiker's Guide to the Galaxy

Alternatively, to paraphrase Pratchett:

Space: It contains nothing. And everything. But there is very little everything and more nothing than you could imagine.
posted by quin at 11:33 AM on March 8 [5 favorites]

I don't know whether reducing light pollution was one of their goals but it's certainly going to be one of the effects.

"Reducing light pollution" and "increasing energy efficiency" are the same thing. So under that technicality I think we could get away with claiming it was their intention, even if they never thought about it :)
posted by anonymisc at 11:34 AM on March 8

Just like the color of our blood (rubies in the US). I hope this doesn't mean anything bad...
posted by Anne Neville at 12:08 PM on March 8

My grandpa has a cabin on Lake Superior. One of my favorite things to do there is gaze at the stars - once we just lay there for hours, enthralled by the glowing band of the Milky Way spread above us, and I grabbed a pair of binoculars, looked at an "empty" section of sky and couldn't think of anything beyond "my god, it's full of stars."

Last time we were there, we arrived long after dark, and I realized that some IDIOT had put a streetlight out near the beach. The entire beach was lit up. I ran out there to pinpoint which house had the offending light - and found myself staring at the moon. It had been so long since I had seen the unadulterated light of a full moon that I had completely forgotten how bright it can be. It was really amazing.

We trade this magic for the yellow wash of streetlights. Our great-grandparents could speak of the light of Venus, and we have to put blackout shades on our windows to sleep. This is progress? No. This is tragic.
posted by caution live frogs at 12:17 PM on March 8 [9 favorites]

"Do you really NEED an empty parking lot blazed like noon even at 2AM?"

A commenter on the blue once said that the only cultural experiences one gets while growing up in the suburbs are getting drunk in parking lots and internet porn. So presumably it's to facilitate cultural expression.
posted by MattMangels at 1:16 PM on March 8

Slight derail on "is the new black".
posted by BWA at 1:23 PM on March 8

quin, I'm reading Diggers right now, and I thought of that line, too.
posted by ocherdraco at 1:52 PM on March 8

I was 17 when I arrived, from NYC , at the Marine Corps Recruit Depot Parris Island,South Carolina in 1955.
The first night I was assigned to guard duty. At midnight I looked up and saw a sky I never knew or imagined existed. To this day I remember it as one of the defining moments of my life.
posted by notreally at 2:03 PM on March 8 [2 favorites]

Of the many, many, many... many Terry Pratchett quotes that I absolutely love, that one is probably my favorite. It so perfectly encompasses both his genius with words and the subject he is explaining.
posted by quin at 2:48 PM on March 8 [2 favorites]

The first time I was at a cabin on the North Shore of Lake Superior and went outside without any lights on... That was what hooked me on astronomy. The Milky Way stretched out overhead, that feeling of being afloat in the universal sea -- it's something everyone should get to experience.

From obnoxious globe streetlamps that actually make me feel less safe to occasionally hearing young Taiwanese kids say "Look, mommy, a star!", light pollution has been a bane of mine for a long time. Every person should get to see the wider universe that we are part of.
posted by jiawen at 3:29 PM on March 8

The City Dark (2012) is a great documentary on light pollution. Highly recommended if you haven't watched it yet.

I never thought much about the effect of city lights until I moved to Seoul and could barely make out Venus some evenings. Hard to chant "star light star bright" when only planets can shine through the pollution. Yet, people can adapt to a lot of things and if you never grew up star-gazing, how do you know what you are missing?

Like a lot of people, I was completely bowled over the first time I saw the night sky without the haze of light pollution. There were so many stars I thought the sky seemed dusty. I had no idea that the sky held anything more than a few constellations.
posted by spamandkimchi at 3:36 PM on March 8 [1 favorite]

Having grown up before the orange sodium vapor lights, I terribly miss the whiter lights. This idea that they provide optimal visibility is, frankly, horseshit. What I tended to see was a replacement of old lights that directed light down to newer units that scattered light much more in an attempt to cover larger areas at lesser cost. Bring on the LEDs and make them point down. I'm fine with that.

Cities will always be bright, and they are getting brighter. Buildings will use more and more LEDs to light their exteriors for advertising, and it won't be downward directed.
posted by Muddler at 3:59 PM on March 8

The fine article linked here is interesting. It never occurred to me that red light would reflect better off of clouds. Sure explains the unpleasant color of humid cities like Houston at night. There really is no good reason for any street lights / house lights to shine up.

There are special telescope filters that try to help with light pollution by selectively blocking wavelengths emitted by artificial lights. Reviews are mixed, and most of what I've read recommends nebula filters instead which only allow light wavelengths that come from deep sky objects. Wouldn't mind trying one though.
posted by Nelson at 4:43 PM on March 8

The first time I actually saw the milky way was in High School, on a Scouting hiking trip to Philmont in New Mexico. I lived in suburban south-western Connecticut, about 40 miles from NYC, and the light pollution was bad enough that only the brightest stars could be seen.

13 years ago, I moved to a rural part of the Shenandoah valley, and realized I now lived in a place where I could see the milky way again. Since then, though, suburban development has encroached enough that the milky way has turned from a bright ribbon across the sky to a dull smudge, and I suspect it will soon disappear entirely.
posted by Blackanvil at 6:09 PM on March 8

When I lived in the northern burbs of Chicago, I drew the short straw and got the south facing bedroom. My room was never not lit. The pink glow of Chicago (and all of the other burbs and their car dealerships and empty, yet well-lit parking lots between the city and my window), while never enough to read by alway made sure I slept with my head covered by another pillow, even with the blinds closed.

Now, living in the greater Tokyo metropolitan area, there is no dark. On rare occasions, I can see Orion, but other stars, almost never. I miss them. I miss that, once, when I was quite young in Kalamazoo, there was a bizarre night where the northen lights reached as far as lower Michigan, and we could easily find a dark area and go out to look at them. Or a fantastic trip, in high school, to Governor Dodge State Park in Wisconsin, where there were no lights blocking out the sky, and no moon that night. The stars alone were enough light to walk along the paths. I miss that, too.
posted by Ghidorah at 6:42 PM on March 8 [1 favorite]

One night in Jamaica, I was sitting on the beach with the sounds of Reggae coming from all the cafes and bars. Then the town's generator went down and we were all sitting in the dark looking into a vast starlit sky. The power was off for a quite awhile and most people went back to their homes or hotels. A few people stayed to gaze at the stars and somewhere nearby some men started softly chanting Rasta songs. I felt warmly connected to nature and life. And the stars, billions, yea gazillions, of stars, so bright.
posted by a humble nudibranch at 11:10 PM on March 8

You know what's crazy about the "billions of stars"? There's really only about 5000. Well of course there are lots more stars but they require specialty optics to see. There are only 5000 naked-eye stars.
posted by Nelson at 8:46 AM on March 9 [1 favorite]

Here's a great shot of the Milky Way from Mauna Kea.
posted by spamandkimchi at 10:38 PM on March 13