The Smithsonian National Museum of Natural History, in Washington, D.C., “Lights Out” exhibit is helping people understand that light pollution is a global problem with broad impact. The effects of light pollution go beyond our diminishing view of the stars; it also impacts ecosystems and cultures on Earth. The exhibit features more than 100 photographs, nearly 250 objects, a history of human-made light, interactive experiences, tactile models and a theater program to discover why dark nights matter, rekindle a connection with the night sky and consider how much light at night is enough.

Astronomers rely on light, both visible and invisible, to understand celestial bodies, and their view of the universe has become increasingly obstructed by artificial light. Biologists have observed light pollution’s toll on plants and animals—from harming coral reefs’ moonlight-triggered reproduction to bats’ ability to pollinate flowers and the grim consequences of disoriented migrating birds. Another area of the exhibition presents people’s ancient and modern-day connections to the night sky through photographs, stories and cultural items. Visitors also learn about simple, but meaningful actions they can take to reduce light pollution, such as aiming outdoor lights downward and using the dimmest settings.