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Discover how light pollution affects astronomy, wildlife, and our planet.
Did you know?
On a truly dark night, the unaided eye can see thousands of stars — including the cloudy band of our own Milky Way.
The essentials
Artificial light that brightens the night sky and hides the stars above us.
Streetlights, buildings, signs, and homes can scatter light through the atmosphere, creating a hazy glow called skyglow. It makes fainter stars harder to see, even miles from a city.
Darker nights reveal more of the universe and make astronomy more accessible.
A dark sky lets your eyes see deeper into space, from the Milky Way to distant nebulae. Protecting it also preserves a shared natural wonder for future generations.
Night lighting can disrupt the natural rhythms of birds, insects, and other animals.
Migrating birds may be drawn off course, insects can circle lamps until exhaustion, and nocturnal animals may avoid important feeding or nesting areas.
Excessive nighttime lighting can interfere with sleep and our natural circadian rhythms.
Cool, bright light at night can signal daytime to the brain and suppress melatonin. Shielded, warmer, lower lighting helps keep bedrooms and neighborhoods comfortable after dark.
Light shining upward or into empty spaces uses energy without helping anyone see.
Efficient fixtures, timers, dimmers, and motion sensors can direct light only where and when it is needed — reducing costs and unnecessary emissions.
Small lighting choices at home can make a meaningful difference for the night.
Aim lights downward, use the lowest useful brightness, choose warm bulbs, add timers, and turn off outdoor lights when they are not needed. You can also support dark-sky initiatives in your community.