Date: May 18, 2011

Title: Light Pollution: Causes, Effects and Solutions

Podcaster: Jason Davis

Links: Astrosaurus (

Description: Light pollution is the introduction of artificial light into the nighttime environment, which hinders astronomical observation and adversely affects wildlife and the environment. This podcast explores the causes, which range from brightly-lit city buildings to improperly designed outdoor light fixtures. Then, we examine the harmful effects of light pollution, including bird fatalities and wildlife nesting issues. Finally, we look at solutions, ranging from urging policymakers to adopt nighttime light ordinances to simply replacing fixtures around your own house.

Bio: Jason Davis, editor and founder of Astrosaurus (, a news blog about space exploration and astronomy.

I first became interested in space flight and astronomy in 1986, when I witnessed the destruction of Space Shuttle Challenger, and the return of Halley’s Comet. I began recording space shuttle launches on VHS tapes, and my family took me to Kennedy Space Center, an experience that remains clear to this day.

I studied Aerospace Engineering in 1999 at West Virginia University, but changed majors after two years of Calculus struggles. Instead, I became a teaching assistant for an introductory astronomy class. Today, I’m an IT systems administrator by day, but still interested as ever in space exploration and astronomy.

Sponsor: This episode of “365 Days of Astronomy” is anonymously supported.


I’m Jason Davis, the editor and founder of astrosaurus, a news blog about all things space exploration and astronomy. You can visit my website at, that’s a-s-t-r-o-a-u-r-dot-u-s. My topic today is light pollution. For more information about the organizations and topics mentioned in my story, you can visit my website and click on the light pollution link.

It’s 10:00PM on a Wednesday night in Chicago, Illinois. It’s springtime, and the sky is clear. I’m standing on the wooden deck on top of my garage. I’m in the Wicker Park area of the city, a trendy little neighborhood packed with restaurants, bars, three-story condos and six figure incomes. Even though it’s 10:00, I have a noticeable shadow as I stand outside. There are orange streetlights all around me, and the sky has an opaque, yellow-orange tint. I start counting how many stars I can see. After a few attempts and a couple blinding encounters with a nearby streetlight, I still can’t make it above ten, and one of them is Saturn, which doesn’t count.

Once inside, I email my parents, who still live in my hometown of Fairmont, West Virginia. “Do me a favor,” I type. “Walk outside and tell me, roughly, how many stars you think you can see.” I receive a reply the next day. “On a clear night,” the e-mail says, “over a thousand.”

Fairmont is a town of about 20,000, and Chicago has 2.7 million. That’s about 135 times as many people. The problem I’m experiencing is called light pollution, which honestly sounded like a silly, abstract concept the first time I heard of it. I had never spent much time in a big city until I moved to one after college, so I had never experienced what it felt like to lose hundreds of stars in the glare of a polluted night sky. As a child, I experienced the opposite during a trip to the remote mountains of West Virginia. I was visiting a friend’s camp, where the closest grocery store is a half hour away, and the winding roads become impassible during the depths of winter snowfall. I was outside, looked up, and was amazed at what I saw. There were simply too many stars to count. The sky seemed to be alive, as if it were a buzzing hub of activity, divided by a fuzzy cloud arching through the night. I realized that for the first time, I was seeing, or at least noticing, the Milky Way, our own galaxy, that had remained hidden in the night sky of a town of only 20,000 people. It was awe-inspiring and beautiful.

Stargazers and astronomers aren’t the only sufferers of light pollution. Migratory birds are often confused by large, illuminated structures in the nighttime sky. Some crash into large office buildings, cooling towers, radio antennae, and power lines. Others become so enchanted by the glow of a large, bright object that they are reluctant to continue onward into the cold night sky, and circle the object until they perish from exhaustion. The remaining survivors are also at risk from urban predators if they fail to continue on their way. FLAP, the aptly-named Fatal Light Awareness Program, says that over a million birds are killed each year in the Toronto, Ontario area as a result of collisions with buildings.

Water quality has also been shown to decline in the presence of unnatural nighttime light. Plankton living in over-illuminated lakes may lower their consumption of surface algae, throwing off delicate ecosystems and watersheds. With nothing to stop the proliferation of algae, plant growth may be stunted, lowering the quality of the water.

If you really want a sad wildlife story, consider that the Florida Fish and Wildlife Commission says that the greatest threat to sea turtles is currently light pollution. Atlantic Sea Turtles will only nest at night. If they crawl out of the ocean and see any light, they often return without laying eggs. The continuing development of coastal areas means there are very few places left where this can happen. When baby sea turtles hatch, they must quickly find their way back to the ocean. But unnatural nighttime light can confuse this process, sending them on circuitous paths away from the ocean, resulting in death from exhaustion or predators.

With the effects of light pollution continuing to be researched and understood, organizations like the International Dark Sky Association have sought to increase awareness of the problem, and create solutions to address it.

One city at the forefront of effective light pollution policy is Tucson, Arizona. Most of Arizona is a mountainous desert, and the state has long been a haven for astronomical research. In the 1950s, Kitt Peak Observatory was constructed in the mountains 50 miles from Tucson. Kitt Peak quickly grew to the most diverse collection of astronomical observation stations in the entire world. But astronomers realized that their pristine view of the stars would not last unless they worked with local policymakers to ensure their skies stayed dark.

Tucson developed its first official lighting ordinance in 1972. Originally, the ordinance was a hard sell. Companies ranging from malls, restaurants, and car dealerships protested at new nighttime lighting requirements. But advocates were quickly able to show that brighter isn’t always better. In fact, focused, more direct light is usually much better for visibility. Sports complexes jumped on board. Police officers became believers. And perhaps most importantly, money was saved. In fact, the International Dark Sky Association estimates that badly designed lighting currently wastes about $10 billion per year worldwide. Traditional outdoor light sources can waste up to half of their energy, throwing it needlessly into the night sky.

Municipalities across the U.S. are slowly beginning to investigate or implement light pollution ordinances. As a result, a new market segment has opened up for businesses able to supply the technology for pollution-friendly light fixtures. A 2008 New York Times article highlights Starry Night Lights, a business that specializes in properly designed outdoor light fixtures. Their feature product is called the “Glare Buster,” which actually has a shockingly simple design – an elongated triangle that directs all light out an opening that’s parallel to the ground. Many similar solutions are energy-star certified, which brings up an added benefit to eliminating light pollution: going green. That’s what makes light pollution such a seemingly straightforward issue: better outdoor lighting saves money, helps the environment, and actually works better.

So let’s say you’d like to get involved. What can you do? The International Dark Sky Association is a great place to start. They have a list of outdoor light fixtures that meet their seal of approval. Some aren’t even very exotic – a quick search revealed an approved feature that is currently in stock at my local Home Depot for $21. If you’re more ambitious, the association has ordinance guidelines you can download to help your local lawmakers draw up their own regulations for future light pollution policies.

To find the magnitude of light pollution in your area, a website called The Globe At Night has guidelines for comparing your view of easy-to-spot constellations with charts on their site. You can then compare your results with other regions using their worldwide map.

Thanks for listening to my podcast. I’ll leave you with a final story about a particularly eye-opening example of light pollution. Again, for more information about the organizations and topics mentioned in my story, you can visit my website at and click on the light pollution link. That’s a-s-t-r-o-a-u-r-dot-u-s.

On January 17, 1994, a 6.7 magnitude earthquake struck Los Angeles at 4:00 in the morning. Many parts of the city lost power, sending terrified residents rushing outside into the night, which was, for the first time in more than a century, completely devoid of electric lights. Residents were shocked at the amount of stars in the sky, along with a mysterious, silvery cloud that seemed to stretch from one end of the horizon to the other. In the following weeks, speculation grew that the appearance of the cloud and apparent brightening of stars were the causes of the quake. Radio stations, emergency services, and local scientists fielded calls as speculation grew, until local astronomers were able to solve the mystery: without any light pollution, the residents of Los Angeles were able to see the night sky as it truly was. And for many residents, it was the first time they had ever seen their own galaxy, the Milky Way.

I’m Jason Davis, thanks for listening.

End of podcast:

365 Days of Astronomy
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