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posted by hubie on Monday January 23 2023, @07:06PM   Printer-friendly
from the point-the-lights-down dept.

Observations from citizen scientists show the sky is getting about 10 percent brighter each year:

The night sky has been brightening faster than researchers realized, thanks to the use of artificial lights at night. A study of more than 50,000 observations of stars by citizen scientists reveals that the night sky grew about 10 percent brighter, on average, every year from 2011 to 2022.

In other words, a baby born in a region where roughly 250 stars were visible every night would see only 100 stars on their 18th birthday, researchers report in the Jan. 20 Science.

[...] "In a way, this is a call to action," says astronomer Connie Walker of the National Optical-Infrared Astronomy Research Laboratory in Tucson. "People should consider that this does have an impact on our lives. It's not just astronomy. It impacts our health. It impacts other animals who cannot speak for themselves."

Walker works with the Globe at Night campaign, which began in the mid-2000s as an outreach project to connect students in Arizona and Chile and now has thousands of participants worldwide. Contributors compare the stars they can see with maps of what stars would be visible at different levels of light pollution, and enter the results on an app.

"I'd been quite skeptical of Globe at Night" as a tool for precision research, admits physicist Christopher Kyba of the GFZ German Research Centre for Geosciences in Potsdam. But the power is in the sheer numbers: Kyba and colleagues analyzed 51,351 individual data points collected from 2011 to 2022.

"The individual data are not precise, but there's a whole lot of them," he says. "This Globe at Night project is not just a game; it's really useful data. And the more people participate, the more powerful it gets."

[...] The good news is that no major technological breakthroughs are needed to help fix the problem. Scientists and policy makers just need to convince people to change how they use light at night — easier said than done.

"People sometimes say light pollution is the easiest pollution to solve, because you just have to turn a switch and it goes away," Kyba says. "That's true. But it's ignoring the social problem — that this overall problem of light pollution is made by billions of individual decisions."

Some simple solutions include dimming or turning off lights overnight, especially floodlighting or lights in empty parking lots.

Kyba shared a story about a church in Slovenia that switched from four 400-watt floodlights to a single 58-watt LED, shining behind a cutout of the church to focus the light on its facade. The result was a 96 percent reduction in energy use and much less wasted light , Kyba reported in the International Journal of Sustainable Lighting in 2018. The church was still lit up, but the grass, trees and sky around it remained dark.

"If it was possible to replicate that story over and over again throughout our society, it would suggest you could really drastically reduce the light in the sky, still have a lit environment and have better vision and consume a lot less energy," he says. "This is kind of the dream."

Journal Reference:
Fabio Falchi and Salvador Bará, Light pollution is skyrocketing, Science, 379, 6629, 2023. (DOI: 10.1126/science.adf4952)

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  • (Score: 5, Interesting) by Snotnose on Monday January 23 2023, @09:49PM (3 children)

    by Snotnose (1623) on Monday January 23 2023, @09:49PM (#1288246)

    Considering I was in the suburbs. Then a new building about 1/4 mile away decided to illuminate it like it was the Taj Mahal all night. Then, about a year later, a high school a mile away put lights on it's football field. After that I could pretty much sit in my pool lounger at 11 PM and read a book.

    Shit like this should be illegal. You want to light your parking lot? Fine. You want to illuminate your football field? Why are you wasting taxpayer's money by lighting my back yard, which is over 1 mile away.

    Once the high school turned on it's lights both of my telescopes went into the closet, they were useless.

    Why shouldn't we judge a book by it's cover? It's got the author, title, and a summary of what the book's about.
    • (Score: 4, Insightful) by sjames on Monday January 23 2023, @11:17PM

      by sjames (2882) on Monday January 23 2023, @11:17PM (#1288264) Journal

      Further, many times the lights are for the perception of 'safety' while they actually reduce safety by night blinding pedestrians while creating dark hiding spots where the bad guys can see you but you can't see them. Also providing nice work lights for people up to no good.

      Good reflectors on that stadium could probably reduce power requirements by re-directing the light that hits your back yard back onto the field.

    • (Score: 2, Interesting) by BlueCoffee on Tuesday January 24 2023, @03:02PM (1 child)

      by BlueCoffee (18257) on Tuesday January 24 2023, @03:02PM (#1288369)

      Light pollution due to urban sprawl became a newsworthy issue in the 1980s, mostly through professional and amateur astronomers pressuring cities to do something about it.

      It was even starting to affect the Palomar observatory in California. Cities listened and across NA outdoor lighting was gradually switch to low presure sodium bulbs because they emit light in a very narrow spectrum and can easily be filtered out with a $50 astronomical filter.

      Unfortunately LEDs emit light across the visible spectrum and cannot be easily filtered. Narrow spectrum LEDs exist but for some reason most cities did not install them-maybe they didn't exist until very recently.

      LEDs, especially unshielded ones, set the world back 50 years in combatting light pollution. That's not progress!

      • (Score: 0) by Anonymous Coward on Tuesday January 24 2023, @08:30PM

        by Anonymous Coward on Tuesday January 24 2023, @08:30PM (#1288418)

        Most of the street lighting is/was high pressure sodium bulbs, but it wasn't about light pollution but rather with the efficiencies of the bulbs. Light pollution is the result of the light fixture and the baffling (or lack thereof), and you get plenty of light pollution with high pressure sodium bulbs. There are low pressure sodium bulbs, and you can find those installed around observatories. The advantage there, as you allude to, is that they put out light in a very narrow wavelength band, almost monochromatic. High pressure sodium has additional spectral lines that pop up, and though they put out most of their light around a certain wavelength, the high pressure of the gas causes additional emission lines, so they aren't quite as yellow looking as the low pressure ones.

        The nice thing about the sodium bulbs is that they put out yellowish light, which is easy on the eyes at night. A lot of the replacement LED bulbs they are using are the "white" bulbs which can have a lot of light put out in the blue. Not only does that scatter easier than longer wavelengths, but it is hard on the eyes at night.

        An easy fix, and what would go a long way towards addressing light pollution would be to require dark-sky friendly light fixtures []. These are just lamp fixtures where the shade or baffle around it doesn't allow direct light to be sent above the horizontal, so think of a simple downward-pointing cone, you just need the entire bulb to be housed where it doesn't stick out under the cone shade. You'll see places want to have an "old timey" look and put in lamps that look like the old gas lamps where the entire bulb is exposed to the sky. All you're doing in that case is throwing almost all of your light upwards where it doesn't do you any good, so you have to keep adding more lamps until you get the brightness on the ground you desire. That is a lot of wasted light, meaning wasted electricity, meaning wasted money. If you want that old-timey Coach style lamp, get one with the bulb mounted in the top [] so that all the light shines down. The lamp outside our house was that coach style and the bulb would shine directly on our bedroom windows. I've replaced our outside lamps with dark-sky friendly ones, and it is wonderful. All the light shines down on the ground and not up on our windows.

  • (Score: 1) by anubi on Tuesday January 24 2023, @12:36AM (3 children)

    by anubi (2828) on Tuesday January 24 2023, @12:36AM (#1288273) Journal

    It's my understanding that Bill Gates has been 'dusting' the stratosphere with calcium carbonate ( chalk ) dust to see if it will bounce enough incoming sunlight back into space, acting as a global 'beach umbrella ' to counteract global warming. []

    This will also certainly screw up ground based telescopes trying to look through hazy air.

    Just throwing this into the ring. I know very little about this other than being aware of it.

    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
    • (Score: 2) by maxwell demon on Tuesday January 24 2023, @04:27AM (2 children)

      by maxwell demon (1608) on Tuesday January 24 2023, @04:27AM (#1288307) Journal

      Has been? Do you have any evidence that he already actually did it?

      The Tao of math: The numbers you can count are not the real numbers.
      • (Score: 1) by anubi on Tuesday January 24 2023, @08:18AM (1 child)

        by anubi (2828) on Tuesday January 24 2023, @08:18AM (#1288337) Journal

        Same questions I have, and why I dropped the link here, hoping someone else is better informed than I.

        I have seen photos of jets leaving enormous contrails criss-crossing the sky and thought maybe that is what they were doing.

        "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
        • (Score: 1, Informative) by Anonymous Coward on Tuesday January 24 2023, @01:02PM

          by Anonymous Coward on Tuesday January 24 2023, @01:02PM (#1288339)

          This test [] is to deploy much higher in the atmosphere (20 km) than passenger jets, and it is to release a small amount of aerosol and measure what happens chemically. As far as I can tell, it hasn't flown yet (based upon a quick search).

          Geoengineering is an interesting topic that needs more debate. I think this is worthwhile to investigate, but I share the reservation about the takeaway from this if something like this turns out to be viable. You know it won't be "great, let's cool things down a bit and get us back in line to where we should be," but it will be "great, now we can continue business as usual and kick that can down the road and just keep dumping CO2 into the atmosphere." The underlying problem will still be there, but it will allow ignoring the issue longer until we get to the next crisis point.

          Contrails are an interesting area of study because it seems the exact conditions under which they form is not well known. There used to be a citizen-science web page or app for people to record when they see contrails, but I can't seem to find that anymore either. (Must be too early for me to be effective with my web searches)

  • (Score: 1, Insightful) by Anonymous Coward on Tuesday January 24 2023, @12:36AM (1 child)

    by Anonymous Coward on Tuesday January 24 2023, @12:36AM (#1288274)

    Now that the air is so dirty it glows from all the reflected light.

    And why don't street lights have lamp shades to keep the light from shining up into the sky?

    • (Score: 2) by canopic jug on Tuesday January 24 2023, @06:20AM

      by canopic jug (3949) Subscriber Badge on Tuesday January 24 2023, @06:20AM (#1288330) Journal

      And why don't street lights have lamp shades to keep the light from shining up into the sky?

      Or, to put it another way, in case the malfeasants don't care about anything else, why are they paying to light up anything other than the ground? If they are paying for illumination which is a sphere shining everywhere instead of a cone shining downward, most of their money is going off target.

      Money is not free speech. Elections should not be auctions.
  • (Score: 2) by driverless on Tuesday January 24 2023, @06:57AM (4 children)

    by driverless (4770) on Tuesday January 24 2023, @06:57AM (#1288333)

    Had a look at the site and the process is laboriously manual and subjective, I was hoping to hook a sensor inside a lightwell to something like a Pi and send in readings, which the site would coordinate with online weather data to get a true reading. Instead you have to manually do everything, including guessing how dark/light you think things were and manually entering a pile of stuff like GPS coordinates. I support what they're doing, but they desperately need some geeks who know this stuff to automate the process for them.

    It also raises some questions about the quality of the data they're collecting if it requires so much (error-prone)-humans-in-the-loop to get.

    • (Score: 0) by Anonymous Coward on Wednesday January 25 2023, @02:33AM (3 children)

      by Anonymous Coward on Wednesday January 25 2023, @02:33AM (#1288471)

      They're saying that the data are noisy, but since there is so much of it, the errors average out.

      If you want to contribute in a more quantitative manner, you can take photographs of the sky or get a Sky Quality Meter and make measurements [].

      • (Score: 1, Informative) by Anonymous Coward on Wednesday January 25 2023, @04:21AM

        by Anonymous Coward on Wednesday January 25 2023, @04:21AM (#1288486)

        Average grows SNR as sqrt, i.e. slowly. Your 12 hour exposure became 144 hours planned over multiple days.

      • (Score: 2) by driverless on Wednesday January 25 2023, @09:32AM (1 child)

        by driverless (4770) on Wednesday January 25 2023, @09:32AM (#1288510)

        Had a look at those (that is, the SQMs) a few years ago, they're crazy expensive for what you're getting. I already feed in data to various collectors for rainfall, wind, temperature, UV levels, PM10 levels, seismic activity, AIS, ADS-B, lightning strikes, rains of frogs, and zombies, and paying that much for a glorified light meter just seems excessive.

        • (Score: 0) by Anonymous Coward on Thursday January 26 2023, @02:05PM

          by Anonymous Coward on Thursday January 26 2023, @02:05PM (#1288698)

          I have a couple of them because of an old project at work. They are basically a calibrated photodiode that gives back the radiance of the sky when you press the button. The fancier model has a USB interface where you can set it logging and walk away. If you are smart with photodiodes (understanding how to bias them, etc.) it wouldn't be hard to do it yourself, but you'll want to make sure you know how to apply the calibration. I think they might give you the parts list and stuff to build your own. The important things that would go into it if they give you a calibration file would be to make sure you give it the proper supply and bias voltage, and use the exact same photodiode part. They worked out all the spectral relationships as well because the I love the units it gives you: stellar magnitude per square arc-second (which is a log scale). It would make for a fun hobby project to build your own, but if you want to skip all of those subtle details, it is easier to just buy one if all you want to do is measure the sky brightness in physical units.

          If you don't care what the physical units are and you just want to look at the sky brightness and how it changes for yourself, then you can quickly throw together a photodiode and data logger (after futzing with your bias/gain settings to get it optimized for night light levels and maybe adding a lens to make sure you are focusing on a patch of the sky and not getting light coming in from the side, etc.) and look at the output voltage of the photodiode.

  • (Score: 1, Funny) by Anonymous Coward on Tuesday January 24 2023, @02:14PM

    by Anonymous Coward on Tuesday January 24 2023, @02:14PM (#1288356)

    Send up thousands of drones with reflective mirrors to direct the light onto the ground. Ideally using AI technomology.

  • (Score: 1) by BlueCoffee on Tuesday January 24 2023, @02:32PM

    by BlueCoffee (18257) on Tuesday January 24 2023, @02:32PM (#1288360)

    LEDs use 20% of the power of incancescents so when everyone switched to LEDs over the past decade, many people installed twice as many. Twice the light for half the price, and it wont break your budget if you leave them on all night.

    It's the middle of a cold snowy winter here but most backyards still have their solar LED lights on and a 100' string of decorative LEDs string along their fence eventhough no one will be sitting outside until April or May.