Four hundred years ago, the twinkling stars cast shadows on a moonless night. Constellations were so intricate as to be unrecognizable today, and some sky landmarks were defined not by individual stars but by the dark spaces between them. The Milky Way appeared so solid that only a magnified view revealed it wasn’ t one body but hundreds of thousands of stars so densely clustered that their faint, ancient light formed a path across the cosmos.
~ the international dark-sky association,“ our endangered night,” fighting light pollution: smart lighting solutions for individuals and communities
According to the nonprofit Dark Sky International, light pollution is defined as excessive, misdirected, or obtrusive artificial light. It includes several components: glare that causes visual discomfort,“ skyglow” that brightens the night sky,“ light trespass,” in which light from one place intrudes on the dark of another place where it is not wanted or needed, and“ light clutter,” with bright or excessive grouping of lighting creating distracting or dangerous visual confusion.
A major exhibit titled“ Lights Out, Recovering the Night Sky” at the Smithsonian National Museum of Natural History, with support from many other organizations including NASA, Dark Sky International, The World at Night, and Illuminating Engineering Society( IES), runs through December 2025. It documents the rise of light pollution, happening at an astounding pace. Every year for the last ten years, the night sky in the United States is 10 percent brighter than the year before. About 80 percent of US residents cannot see the Milky Way at night.
The Bortle Scale, developed by astronomer John Bortle, rates geographic areas on a scale of 1 – 9 according to their light pollution. Class 1 is the darkest, ideal for stargazing, and Class 9 is“ inner-city white” at night. For reference, downtown Washington DC and most of the Northern Virginia suburbs are Bortle Scale Class 8 or 9. Most of Montgomery County is Class 6 or 7, and the very northern regions of the County on the outer rims of the Ag Reserve are Class 5.
Aerial PHOTOS: Courtesy Tonya Kusak
Top: Flying over Montgomery County’ s Agricultural Reserve towards Leesburg, Virgina; above: a view from Loudoun County, Virginia, looking across the Potomac River into the Ag Reserve in the right section of the photo.
The Real Threat: Yet Another Challenge to Agriculture
Loss of night stargazing is a minor inconvenience for humans, compared to larger problems light pollution creates, especially for the delicate environment that supports agriculture. A key problem is that unfocused light at night interferes with the hunting, foraging, and breeding patterns of important nocturnal animals. Bats, opossums, foxes, skunks, and raccoons all depend on the cover of darkness to safely go about their essential work of consuming massive amounts of insects, larva, tics, small rodents, or caterpillars, which protects crops and keeps the ecosystem in balance. Some of these nocturnal animals even“ clean up the mess” of dead animals, reducing the spread of disease to farm animals, domestic pets, and wild animals. In addition,
12 plenty I spring sowing 2025