A few years ago, I purchased a small cabin—a place to read, write, and spend time with family away from the stresses of contractor life. On my first clear night there, I was amazed by the brilliance of the sky. Between the major constellations were hundreds of subtler points of light; through my binoculars, I could see thousands more, invisible to the naked eye. And arching from tree line to tree line were the wisps of the Milky Way. I was struck by how much more I could see here than at my home twenty miles away. There, on a residential street in a small city, streetlights, porch lights, and the glow of the nearby commercial strip wash out all but the brightest stars.

Bright artificial light is a recent phenomenon. Prior to Edison’s invention of the light bulb in 1879, candles, oil lamps, and lanterns were most households’ only light source; gas lights, which burned methane and other combustible gases extracted from wood and coal, were used in wealthier homes. These combustion-based light sources produced only dim light; they also polluted indoor air and created a ubiquitous fire hazard. Except in cities, where gas lights illuminated some streets, outdoor lighting was provided mainly by portable sources like lanterns and torches.

Electric light offered a brighter, safer, and more convenient alternative. In the late 19th and early 20th centuries, it appeared in cities along with the first generating stations and distribution grids. Initially serving commercial buildings, streetlights, and wealthy homes, power lines were gradually extended to middle- and working-class neighborhoods. Not until rural electrification efforts in the 1920s and 30s did electric lighting become widespread in sparsely settled areas.

Most of us now live in areas awash with artificial light from homes, businesses, and public infrastructure. In many ways,…