Feature Article

Light Pollution: Efforts to Bring Back the Night Sky

August 1, 1998

Light pollution is clearly evident in this composite nighttime satellite photo of the United States (1978).

Source: International Dark-Sky Association
When I began thinking about an article on light pollution, three very different experiences came to mind. The first was 25 years ago, sleeping under the stars in Alberta, Canada. I can still picture that night sky: resplendent with tens of thousands of sparkling stars on a solid black background and the Milky Way’s broad band stretching from horizon to horizon. The second experience was here in Vermont about a year ago. Following a planning commission meeting, I watched a rare luna moth—the first I had seen in quite a few years—circle the bright mercury-vapor light outside our town office. I knew that this large, pale green moth would be alive only a few hours (adults live just long enough to find a mate) and would likely perish circling the brilliant globe of blue-white light. The third experience was a few weeks ago in Boulder, Colorado. Late one night, from the porch of a house perched on the foothills above the city, we scanned the nightscape below. As far as the eye could see, there were artificial lights staring up at us—the few hundred visible stars were losing the battle for visibility above the burgeoning metropolis.

Light pollution is something that few of us give much thought to. Astronomers have championed the call for limits to our night-sky pollution because it impinges on their ability to study celestial bodies; some poets mourn the loss of a spiritual connection to the heavens—but for most people light pollution is not even an aesthetic affront.

Three-fourths of Americans grow up never having seen the Milky Way. The man-made wonders of fireworks and laser light shows have replaced the natural wonders of a brilliant night sky for children today. But light pollution is about more than astronomy and aesthetics. It is wreaking havoc in certain natural systems—from sea turtle nesting in Florida to migrating birds in Toronto and sycamore trees in urban parks. There are some who suggest that human health is affected by lack of darkness. And because light pollution is really a symptom of waste, we are also paying a price for it in resource depletion and the multifarious impacts associated with generating the electricity to power it. This article reviews some of the issues involved with light pollution and presents strategies for bringing back the darkness.