The Night Sky: Colorado’s Darkest Natural Resource

Since gold-seeking pioneers of the late 1850s pulled their wagons into what’s now Settler’s Park, Boulder's inky night sky has acted as both a resource and an asset to our area’s quality of life. However, over the years, the brilliance of the night sky has slowly diminished due to unnecessary light and glare from inappropriate lighting. This misdirected and obtrusive overuse of artificial light is known as light pollution. 

The importance of the night sky in any rural area—and particularly in a place as beautiful as Boulder—is immeasurable. With light pollution, not only does wasted light shine skyward and reflect out into the atmosphere, decreasing the ability to see stars and other astronomic elements, but it’s also known to have a negative, disorienting effect on wildlife, and can reduce visibility of the mountains.

Additionally, minimizing light pollution saves energy resources and reduces energy costs. In the United States alone, it’s estimated that at least $1.5 billion is wasted annually on the electricity for outdoor lighting that’s emitted toward the sky. For comparison, the production of this amount of electricity is equivalent to burning six million tons of coal. (I’ll give you a minute to let that sink in.) 

To tackle these concerns, Boulder initiated an Outdoor Lighting Ordinance, which went into effect in November 2018. Guidelines differ by property type, but essentially, bulbs can’t be brighter than 900 lumens, which translates to 60 watts for incandescent bulbs and 15 watts for LED. They also need to be under 3,000 Kelvins, a measure of where the light falls on the color spectrum—the yellower the light, the better. Fixtures should direct light toward the ground or diffuse it, so you can’t see the bulb directly.

But dark skies weren’t always the precious commodity that they are today. It wasn’t until 1886 that Boulder’s streets were illuminated by anything other than lanterns. Until that time, it was necessary for those moving around at night to carry a lantern with them to avoid falling into potholes or irrigation ditches. 

In 1890, city council accepted a proposal from the Electric Light Company to put in 20 lights for $10 per month, to be used all night, bringing Boulder’s grand total of electric lights to 27. The new lights were installed at intersections on Valley Road (now Arapahoe), Water Street (now Canyon), Walnut Street, Pearl Street, Spruce Street, Pine Street, Hill (now Mapleton), and Bluff.

Over the decades, as Boulder grew and its light shined even brighter (pun intended), the dark skies took second stage to the glow of growth, leading to some recent thoughtful intervention to take back the night. 

To celebrate our dark skies as a protected natural resource, Gov. Jared Polis proclaimed June 2019 as Colorado’s first-ever Dark Sky Month. The month is dedicated to drawing awareness to the importance of clear night skies, as well as the negative environmental, economic, and cultural impacts of light pollution. The saying, “we’ll leave the light on for you”? It may just become a thing of the past.