December 2025: Dark Turns., Light Pollution News

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This Episode:

It’s our last official episode of the year! 2026 is right around the corner! But first, we have a lot to talk about. For instance, researchers tracked insects using weather radar in the UK, we’ll let you know what they found! Do modern car headlights actually make you safer? And, it’s not just space mirrors you need to worry about!

With me this episode are lighting designer, Dr. Amardeep Dugar; Cliff Valley Astronomy’s own, Stephan Picard, and the author of the new book, “Creatures of Darkness,” Dani Robertson!

Host:

Guests:

Dr. Amardeep Dugar

Dr. Amardeep M. Dugar is the founding principal of Lighting Research & Design and a trained architect who advocates for all elements of lighting design, education, and research. He holds a Masters degree in Architectural Lighting from the University of Wismar/Germany and a Ph.D. from Victoria University of Wellington/New Zealand, which solidified his professional and academic leadership role. Dr. Dugar is a highly accomplished professional, having been named the Outstanding Young Scientist at the India International Science Fest 2016 and one of the 40-Under-40 Hottest Lighting Designers in the World 2017 by Lighting Magazine UK. His career includes working on high-profile projects, teaching at architecture schools, and conducting lighting workshops to educate students and professionals on the importance of lighting. He is also the co-founder of the Virtual Lighting Design Community (VLD Community), an online platform for lighting. He believes in the balance of body and mind, a philosophy drawn from his dedicated practice of yoga, which deeply influences his life-centered approach to lighting.

Dr. Dugar maintains a significant presence in the professional lighting community, holding numerous certifications and memberships. He is a Certified Lighting Designer (CLD), a professional member of the International Association of Lighting Designers (IALD) and the Lighting Designers Association of India (LiDAI), and a member of the Illuminating Engineering Society (IES). Furthermore, he is a fellow member of the Society of Light and Lighting (SLL) and the India Society of Lighting Engineers (ISLE). His leadership roles include serving on the IES Board of Directors, Chairing the IES Global Development Committee, and acting as Past President of LiDAI. Dr. Dugar has been a frequent presenter at international conferences, including the IES Annual Conference, Light Fair International, IALD Enlighten, and the Professional Lighting Design Convention, among others.

Dani Robertson

Dani Robertson, a Dark Sky Officer for Eryri National Park and the Areas of Outstanding Natural Beauty, is originally from Greater Manchester but moved to the Welsh countryside at an early age. She is prolific in conservation work, championing the darkness for all, and is a regular speaker at public outreach events. Her advocacy for night skies was recognized by the International Dark Sky Association in 2022, when she received the Dark Sky Defender Award. All Through the Night was her first book and equipped readers with the tools for defending our skies. Be on the look for for her new book, Creatures of Darkness!

Stephane Picard

Astrotourism entrepreneur, CEO of Cliff Valley Astronomy.

Full Article List:

1. Remote Welsh island with population of three people searching for new tenant family, BBC News.
2. Dodge Introduces New Truck Headlights That Blast Gamma Ray Bursts Into Your Eyeballs, Babylon Bee.
3. Headlight complaints abound, but glare-related crashes haven’t increased, Joe Young, IIHS.
4. AAA: Nighttime Safety Improved with Pedestrian Detection Effective Rates Rising from 0% to 60%, Brittany Moye, AAA.
5. Letter to the editor: Breckenridge isn’t being fair with its DarkSky initiatives, Garren Riechel, Summit Daily.
6. Ordinance 25-37, Raritan Township.
7. Raritan Township Revokes New Light Ordinance, Citing Concerns From Residents, David Levitt, Tap Into Flemington/Raritan.
8. Palo Alto faces glaring concerns over new ‘dark sky’ law, Gennady Sheyner, Palo Alto Online.
9. Spatio-Temporal Variation in Aerial Arthropod AbundanceRevealed by Weather Radars, Global Change Biology.
10. Artificial light at night alters earthworm communities and soil aggregation, Journal of Applied Ecology.
11. Web placement in grass spiders is driven more by artificial light at night than by prey, Animal Behaviour.
12. Nocturnal flight call monitoring reveals in-flight behavioral alteration by avian migrants in response to artificial light at night, Biological Conservation.
13. Boy’s clear view of the universe sparks pledge to protect night sky, Patricia Lane and Siddharth Patel, National Observer.

Light Pollution News: December Highlights

Bardsey Island: Europe’s First Dark Sky Sanctuary Seeks Island Caretaker

Bardsey Island, located off the coast of North Wales near the Llyn Area of Outstanding Natural Beauty, offers a unique opportunity for aspiring dark sky enthusiasts. As Dark Sky International’s first Dark Sky Sanctuary in Europe, this remote island position combines conservation work with pristine stargazing conditions.

Automotive Headlight Glare Study: IIHS Research Challenges Common Perceptions

A groundbreaking Insurance Institute for Highway Safety preprint study analyzing eight years of crash data (2016-2024) reveals surprising findings about headlight glare and road safety.

Key Research Findings:

• Solar glare significantly more impactful than headlight glare on automotive accidents
• Nighttime crashes attributed to glare: only 0.1-0.2%
• Glare-related accidents decreased over study period
• Drivers over 70 most affected by glare conditions
• Study covered 11 states with glare-tracking capabilities

The IIHS headlight rating system, implemented in 2016, shows dramatic improvements in modern automotive lighting design balancing visibility with glare reduction.

Pedestrian Safety Technology: AAA Reports on Automatic Emergency Braking Systems

AAA research reveals pedestrian automatic emergency braking (PAEB) systems achieve 95% daytime collision avoidance but show variable nighttime performance, especially with pedestrians wearing dark clothing. This highlights ongoing challenges in artificial intelligence-based safety systems under low-light conditions.

Municipal Dark Sky Ordinances: Progress and Challenges Across North America

Breckenridge, Colorado: Enforcement Equity Concerns

Dark Sky ordinance enforcement faces criticism from resident Garren Riechel regarding unequal application. The ordinance, originally passed in 2007 but enforced beginning 2024, allegedly holds homeowners to stricter standards than commercial ski resorts.

Raritan Township, New Jersey: Light Trespass Regulation

Raritan Township’s Ordinance 25-37, unanimously passed October 7th, represents progressive light pollution policy in densely populated regions.

Palo Alto, California: Comprehensive Outdoor Lighting Reform

Palo Alto proposes robust outdoor lighting ordinance following failed spring 2025 attempt.

Ecological Impact Research: How Artificial Light Affects Wildlife Populations

UK Nocturnal Insect Decline Study (2014-2021)

Weather radar analysis tracking flying insects at 500-700 meters altitude reveals concerning population trends.

Research Findings:

• 11.2 trillion daytime flights versus 5 trillion nighttime flights
• No population decline in diurnal insects
• Significant decline in nocturnal insects
• Geography and temperature more influential than artificial light at night
• Study period: April through October

Earthworm Population Decline: UK Loses One-Third Over 25 Years

Journal of Applied Ecology study examines artificial light as potential driver of earthworm decline, given their high light sensitivity.

Research Methodology:

• 26 streetlights monitored over 9 years
• Bright zones: 6.86 lux average
• Dim zones: under 1 lux average

Species-Specific Responses:

• Anecic earthworms (deep burrowing): juveniles avoid blue-spectrum light
• Epigeic earthworms (surface dwelling): juveniles attracted to blue light
• Endogeic earthworms (soil dwelling): attracted to brightness, deterred by blue spectrum

Spider Web Construction Preferences

Animal Behaviour journal research demonstrates grass spiders preferentially build webs near artificial light sources, independent of prey density. This behavior represents a stronger driver than food availability alone.

Migratory Bird Vocalization Patterns at White Sands Missile Range

Biological Conservation study at New Mexico’s White Sands Missile Range (2021-2023) examined nocturnal call frequency at contrasting light levels.

Site Specifications:

• Dark sites: no lights within 200 meters, averaging 0.06 lux
• Bright sites: artificial light within 5 meters, averaging 30.44 lux

Key Findings:

• Increased bird calls at dark sites, especially during early fall migration
• Warblers consistently preferred dark sites
• Sparrows showed no lighting preference
• Cloud cover reduced calls at dark sites, no impact at bright sites
• Moon brightness reduced calls at bright sites, increased at dark sites
• Shielded, warm-colored lights increased bird activity
• Blue-spectrum lighting reduced bird activity

Youth Advocacy: 12-Year-Old Canadian Champions Dark Sky Protection

Siddharth Patel, a 12-year-old Dark Sky International advocate from Canada, demonstrates that light pollution awareness transcends age barriers.

“Light pollution is not hard to fix. We just have to do it.” – Siddharth Patel, National Observer interview

Light Pollution News: December Read Along

Well, let’s get things started today – this last Light Pollution News episode of 2025…and you’re in luck, we’ll start off with what I’m sure will be a Welsh lesson for all of us here…well except for Dani. 

Anyone here ever want to live on their own private island? Well, you may be in luck, Bardsey Island, is offering you the “opportunity of a lifetime,” should you wish to take it. Bardsey Island sits off of the coast of North Wales, adjacent to the, and you’ll have to help me here, Dani – the Llyn Area of Outstanding Natural Beauty. 

While living on the island, you’ll help care for its 200 sheep and 25 Welsh Black cattle, and you’ll meet the 30,000 Manx shearwater that call it home. One of the perks to living here is that you’ll experience life under a true “star-spangled” sky – as Bardsey is Dark Sky International’s first Dark Sky Sanctuary in Europe. However, be forewarned, you’ll be drinking well water, living without electricity, and I’m assuming, if other on-site accommodations, which include “self-catering cottages” are any indication, you will not have access to hot water or showers, either. 

The island isn’t very big, it’s only a mile and a half long and a half a mile wide. You’ll be sharing the space with conservationist volunteers, a resident farmer named Gareth, and vacationing visitors

Here in North America, it’s such a prevalent nuisance that the satirical website, the Babylon Bee, just published this pertinent news article ‘Dodge Introduces New Truck Headlights That Blast Gamma Ray Bursts Into Your Eyeballs!” 

Per the article, Dodge spokesman Dale McMillan says, “These babies will blast you right straight in your retinas! You’ll be seeing them when you blink your eyes for days!…If you can ever see anything again, I mean – If anyone can see after this, they must be Superman! We think you’ll love them!”

McMillan is further quoted as saying, “With our new gamma ray lights, we ensure no one on the road will be able to see anything!…“Making other drivers say “Argh WHAT IS THAT FLAMING BRIGHT LIGHT?!,” is just part of what we do here at Dodge.  

Well, quite to the contrary, it appears in a new paper developed by the Insurance Institute for Highway Safety, that these soul piercing beams of light actually may not impact drivers as much as we all complain about. 

The preprint version which is pending journal publication, found that, you know what, those lights actually make us safer! Now the authors don’t appear to be condoning gamma ray headlights. But what they are saying is something that may resonate with you listening at home. Overall, the findings indicate that solar glare was vastly more impactful than headlight glare on being involved in automotive accidents. 

The study looked at eight years of data from 2016 through 2024, which involved 11 states for which the police are able to denote glare as a contributing factor. Of that segment, only two states broke out solar glare vs headlight glare. As far as glare is concerned, the researchers bucketed glare into four categories based on the sun’s appearance in the sky: high sun (sitting above 20 degrees to the horizon), low sun (between 0-20 degrees), twilight (-6 to 0 degrees), and night (below -6 degrees). 

In the dataset, glare was only reported to impact nighttime crashes between .1-.2% of the time, and glare coded accidents actually went down over time, with the highest rate being in 2015. Now, there are other nuances here, including weather, road design, driver age and car age, with drivers over the age of 70 appearing to be most affected. 

I will note that the IIHS, which commissioned the study, has a headlight rating system that started in 2016, measuring visibility and glare, and claims to have seen a dramatic uptick in the positive scoring of the modern car headlights over that decade long timeframe.

I’ll close out of the automotive news with this interesting piece out of the roadside assistance membership organization, AAA.  The pedestrian automatic emergency braking systems of new cars still have work to do in order to identify people at night. AAA says that the PAEB systems have vastly improved to avoid daytime collisions with pedestrians 95% of the time, they are quite varied at night, specifically if the individual is wearing dark clothing. 
Over in the policy world, we have another piece in the long saga of Breckenridge. This time, from Garren Riechel, who wrote in to Summit Daily to complain about a lack of fairness in the recently enforced Dark Sky ordinance. You’ll recall that the ordinance originally hit the books in 2007 but took until 2024 to enter into force, 18 years too soon according to Riechel. 

Riechel does bring up some good points about fairness, however! He scoffs at the chiding of homeowners to comply to a lighting code while resorts appear to skate away harm free, pun intended. 

In much the same vein, with have the curious case of Raritan, New Jersey. As one may say about Manhattan, if you can make it there, you can make it anywhere. Well, I’m under the firm belief that if you can create a community with responsible lighting in a place like New Jersey, you can do it anywhere. 

Some specifics about Raritan’s Ordinance 25-37. The ordinance specifically attacks the most useless kind of lighting, that is, light trespass. These are lights that are aimed outward with no care to how they impact their neighbors or wildlife, sometimes done with the intent to intimidate or control others. 

Ordinance 25-37 prohibits light trespass onto adjoining properties and roadways. It allows for motion sensor lighting provided they are shielded and aimed downward, with a max of 10 minutes of activation. It does not apply to holiday lighting or to landscape lighting, and it applies between the hours of 11pm to 7am. 
For you at home, Raritan sits slightly north of dead center of New Jersey, and is relatively adjacent to the area around Rutgers University.  Ordinance 25-37 unanimously passed on October 7th. All seemed well…but then some residents complained, and the community tabled enforcement of the ordinance. The township committee was met with stories like Charles Walton’s, who argued that he needed the lights because he’s seen coyotes and black bears near his property at night….of which, I guess he’s somehow trying to claim that lights are going to scare off the bears?  This may come as a surprise to anyone listening today, but I have it on good order that bears don’t give a hoot about if your lights are on or not at night…nor do coyotes. So maybe a better solution would be to bring in your trash can.

Real quickly, at the risk of being too US-centric in policy news, I do need to briefly mention the following. Palo Alto, California is looking at installing a new, more robust outdoor lighting ordinance. A prior one that applied to new construction failed to pass in the Spring. The new ordinance creates a 10pm curfew on lighting except for areas deemed for safety – ie building egresses and parking areas. It extends to all commercial and residential with an compliance term starting in 2029 for commercial properties and 2034 for residents. However, Palo Alto Planning and Development Services staff have voiced concerns about enforcement given the potential hours of violation.
Let’s jump into some ecology news. As always, you listening at home can find all of the ecology stories we both cover and don’t cover in the show over on our ecology tab. I’ll have a 2025 recap page of the ecology news built sometime in early 2026. But for now, I do have a couple of items that I wanted to put in queue before we bolt this episode. 

This one comes from your neck of the woods, Dani.  Past guest, and someone whom I had the privilege of meeting in person the other day, Jeff Buler works analyzing weather radar to track bird trends and activity. Well, Jeff isn’t part of this team, but researchers analyzed weather radar across the UK in much the same manner, and analyzed data covering the years of 2014 – 2021 to identify patterns in flying insect activity. The focus was insects that flew at 500 – 700 meters in altitude (just over 1.5 – 2K feet in American terms). 
The majority of insects fly during the day, clocking in at 11.2 trillion daytime flights, versus the 5 trillion nighttime flights (or about 1/3 of the flights occurred at night). This data only included the months of April through October. The overall findings showed no population trend for daytime insects, but an overall decline for nocturnal insects. To which, geography and temperature gradients were significant factors and Artificial Light at Night was a much lower influencing factor. But, despite these findings, it should be noted that this is a first pass at using radar for analysis, the study really just plotted changing insect activity over the course of seven years against various variables.

Some new information on how artificial light at night affects earthworms came out in the Journal of Applied Ecology. According to the study, the UK has seen 1/3 of their earthworm population disappear over the past 25 years. Researchers noticed that no one has tested the rise in artificial lights as a potential driver of the die off, for which, apparently, earthworms are “highly” sensitive to light. 

They looked at 26 streetlights which stayed lit for 9 years sampling soil from directly under the lights to areas that were deemed “dim” but adjacent to the lights. For you at home, the brightly lit samples averaged 6.86 lux while the ones designated as dim averaged just under 1 lux. 

They found that on the whole, bluer light reduced biomass and earthworm abundance. An interesting twist, this study selected three earthworm types. The first one, the deep burrowing, but surface feeding earthworms (anecic), it was found that younger earthworms avoided the bluer lit spectrums. Jouveniles in the surface dwelling type (epigeic) were actually attracted to the bluer light. And the soil dwelling (endogeic) earthworms were attracted to the brighter lights but deterred by the bluer lights.

Some additional ecology news, from the journal, Animal Behaviour, it’s found that spiders react positively to lit areas. Grass spiders were seen to have a preference for building webs close to light sources. This preference appeared to be independent and more significant than the density of prey in an area. Without light, the spiders tended to build webs closer to prey. 

Lastly for ecology, I found this study to be very interesting. From Biological Conservation, researchers set up recording centers at dark sites for which there were no lights within 200 meters and light sites that had artificial light within 5 meters. The dark sites averaged .06 lux and the bright sites averaged 30.44 lux. These were all at the White Sands Missile Range in New Mexico between 2021- 2023. 

The team found that birds actually called more frequently at dark sites, especially in early fall migration season. Warblers consistently preferred to talk more at dark sites, but sparrows didn’t seem to care if an area was lit or not. 

Overall, cloud cover seemed to depress calls at dark sites, while it didn’t impact call frequency at bright sites. And moon brightness did the opposite, reducing frequency of calls at bright sites, while increasing call count at dark sites. Shielded lights and warmer colored lights increased bird activity, while bluer colored lighting lowered bird activity.

I want to close things out tonight, this last episode of 2025, w this story from your country, Stephane. A 12 year old named Siddharth Patel has turned his passion for space into advocacy work. Patel participates in the Globe At Night and is a Dark Sky International advocate, which for him includes making school presentations, taking light measurements of his community, and using astrophotography as outreach. 
Just goes to show that there’s no right age to recognize our loss of night. And I agree with Patel here – he was interviewed by the National Observer, whereby he said, “I am filled with hope. Light pollution is not hard to fix. We just have to do it.”