Starry Night: The Effects of Light Pollution

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Remember when you would lay in the grass at night, spotting all kinds of constellations, maybe glimpsing at a shooting star, or marveling at the cloudy outline of the Milky Way? No? This outdoor pastime has all but disappeared from our lives as light pollution from buildings, billboards, street lamps, and even the security lights from your neighbor’s garage make it impossible to see but a few stars at night. The dark sky has become a rarity in the modern world and advocates across the globe are finding ways to bring it back. 

Paul Bogard, author of the picture book To Know a Starry Night with photos by astro-photographer Beau Rogers, says the effects of light pollution can be felt in most American cities. Artificial light has revolutionized the way we live, extending our days into the night. But at what cost?

According to a 2016 study published in the journal Science Advances, more than 80% of the world’s population lives under light-polluted skies. Light pollution can impact sleep, general health and negatively impacts the environment, killing millions of birds each year and disrupting the seasonal cycle of trees.

Another effect? The beautiful stars in our skies are clouded by the bright beams of lights all around us. We discuss the effects of light pollution and how stargazers can bring about change in their local communities. If you look at a dark sky map, you’ll see that Europe is lit up like a Christmas tree, as is much of the eastern half of the United States. Australia, on the other hand, is one of the darkest places in the world and a Mecca for night sky enthusiasts.

Amateur astronomers describe the night sky using the Bortle scale, which is named after John Bortle who created it in 2001. It describes light pollution and its effects on a scale from one to nine based on celestial objects visible to the naked eye. For example, if you’re standing in Times Square in New York City at midnight on a clear night, you won’t see any stars. That’s a Bortle nine. If only the brightest constellations like the Big Dipper barely glow and the Milky Way is invisible, that’s a Bortle class seven. Most suburbs in the country come in around a Bortle seven.

One organization committed to the cause is the International Dark Sky Association – a leader in protecting areas known as dark sky reserves. These sites meet a number of criteria, including an exceptional view of the Milky Way with the unaided eye. But communities can also pass ordinances and convert into certified dark sky destinations. In Arizona, Tucson and Flagstaff are two cities that have done so. So, how can you push for a darker sky in your own community?

Bettymaya Foott, director of engagement at the Internal Dark Sky Association, says it’s important to build a following rather than approach city hall on your own. She suggests searching for a local astronomy club or a nearby Audubon Society. Such a group got management at the John Hancock Center in Chicago to turn off lights at night because they disoriented migrating birds. Even local tourism councils might help to build a dark sky coalition when they learn about the benefits of astro-tourism.