To respond to the Do Now, you can comment below or tweet your response. Be sure to begin your tweet with @KQEDEdspace and end it with #DoNowLight

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Do Now

Answer one of the following questions: How has light pollution affected you? What effect of light pollution can be the most damaging? Is it most effective to change the law, create awareness or utilize technological advancements in addressing light pollution?


Humans have been using artificial light since the invention of the light bulb in the late 1800s. Artificial illumination allows us to stay active after the sun goes down. It helps us drive more safely at night. And some argue that it keeps crime-ridden areas safer…But artificial light also causes its own kind of pollution.

Dispersion of artificial light outside its intended area and above the horizon creates light pollution, and this form of pollution intensifies with increasing urbanization.

Light pollution is caused by inefficiently pointed, reflected and scattered artificial light in our atmosphere. The most noticeable impact of light pollution emerges when stargazers attempt to observe the night sky. However, this type of pollution has negative manifestations on human health and wildlife too.

Not only has the concept of seeing stars become alien for most city dwellers, healthy sleep patterns have also been on the decline. Bright lights can disrupt our circadian rhythms, affecting the body’s production of melatonin, which has been linked to breast cancer. Light pollution also has connections to nearsightedness, insomnia and weak immune systems.

Natural ecosystems are changing in conjunction with city ecosystems. Prey are losing darkness useful for hiding from predators, and unnatural wildlife interactions are emerging. Nocturnal wildlife faces interruptions to their breeding patterns. Disoriented birds crash into well-lit buildings or migrate at unusual times. Baby sea turtles move towards artificial light on the beach rather than following the moon’s glow out to sea.

Light pollution also results in wasted energy and money. The International Dark-Sky Association estimates that one-third of all lighting in the U.S. is wasted, costing about two billion dollars per year. The money wasted in coal and oil equates to generating 14.1 million tons of carbon dioxide per year.

Some legislative approaches criminalize light pollution, but these have only taken effect in a few countries such as Slovenia and the Czech Republic. “Lights out” programs, annual “switch off” events, and “Earth Hour” have emerged to save electricity and bring light pollution to public awareness. Some companies have created intelligent lighting and shades to efficiently direct artificial light.


NPR’s All Things Considered segment Turning It Down: Cities Combat Light Pollution By Going Dim – Mar. 3, 2013
Bright lights are part of a city’s ecosystem. Think of Times Square or the Las Vegas Strip or right outside your bedroom window. Electric lighting is ubiquitous in most urban and suburban neighborhoods. It’s something most people take for granted, but appreciate, since it feels like well-lit streets keep us safer. But what if all this wattage is actually causing harm?

To respond to the Do Now, you can comment below or tweet your response. Be sure to begin your tweet with @KQEDedspace and end it with #DoNowLight

For more info on how to use Twitter, click here.

We encourage students to reply to other people’s tweets to foster more of a conversation. Also, if students tweet their personal opinions, ask them to support their ideas with links to interesting/credible articles online (adding a nice research component) or retweet other people’s ideas that they agree/disagree/find amusing. We also value student-produced media linked to their tweets like memes or more extensive blog posts to represent their ideas. Of course, do as you can…and any contribution is most welcomed.

More Resources

Northwestern University video Light Pollution: An infographic – Mar. 18, 2013
An animated infographic detailing the effects of and solutions to light pollution.

TEDxTalk video Light Pollution: John Garrett at TEDxTemecula> – Nov. 18, 2012
John Garrett uses his skills as a graphic artist and photographer and his wry sense of humor to teach local schoolchildren and community groups about astronomy. As vice president of the Temecula Valley Astronomers, he gives presentations in Temecula, Murrieta, Wildomar, and Menifee. His topics range from atmospheric optics to light pollution, climate, common observing, archeoastronomy, and exoplanets.

Scientific American post Citizen Scientists Track Light Pollution as Humanity Loses Touch with the Night Sky – May 16, 2013
Step out into the darkness a few hours after sunset. What do you see overhead? If you live in a relatively unpopulated part of the world, you might see the broad stripe of the Milky Way splashed against a backdrop of black sky punctuated by countless stars.

KQED Do Now Science is a monthly activity in collaboration with California Academy of Sciences. To participate in this discussion, we post our science activities every second Tuesday of the month.

Lights Out: The Harmful Effects of Light Pollution 8 March,2017California Academy of Sciences



California Academy of Sciences

The California Academy of Sciences is a leading scientific and cultural institution based in San Francisco. It is home to an aquarium, planetarium, natural history museum and research and education programs, which engage people of all ages and backgrounds on two of the most important topics of our time: life and its sustainability. Founded in 1853, the Academy’s mission is to explore, explain and sustain life. Visit for more information.

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