Light Pollution Matters

The sun, the moon and the stars would have disappeared long ago . . . had they happened to be within the reach of predatory human hands.Havelock Ellis, The Dance of Life, 1923

Thank God men cannot fly, and lay waste the sky as well as the earth. —  Henry David Thoreau, 1861

1 Before Blackout Todd CarlsonTowards Toronto Goodwood Ontario  2 During Blackout Todd CarlsonMWay Blackout Night towardsToronto 
Before and during the 2003 Northeast blackout, a massive power outage
affecting 55 million people. Courtesy of Todd Carlson


Ellis could not have predicted the revolutionary impact artificial lights would have on our planet any more than Thoreau could have predicted powered flight.


Less than 100 years ago, everyone could look up at a spectacular starry night sky. Now, millions of children across the globe will never experience the Milky Way where they live.


Light pollution not only impairs our view of the Universe, it hurts the planet by increasing energy consumption, wasting money and harming the health and safety of humans and wildlife.

 Light Pollution by Cestomano 600
Credit: Flickr user Cestomano



What is Light Pollution?

Light pollution is excessive or inappropriate outdoor lighting. Common forms of light pollution include:

  • Glare – excessive brightness that causes visual discomfort
  • Sky glow – brightening of the night sky over inhabited areas
  • Light trespass – light falling where it is not intended or needed
  • Clutter – bright, confusing and excessive groupings of light sources



Light Pollution Diagram 680px

The info-graphic above illustrates the different components of light pollution and what "good" lighting looks like. (Image by Anezka Gocova, in "The Night Issue", Alternatives Journal 39:5 (2013). 


How Bad is Light Pollution Near You?

To find out how bad light pollution is where you live use the NASA Blue Marble Navigator (right) for a bird's eye view of the lights in your town and check out the Globe at Night interactive light pollution map (left) data created with 8 years of data collected by citizen scientists.  

Globe-at-Night-Map2013-hero2 earth lights

new GaN logo4

You Can Help Save our Stars!

Be a citizen-scientist and help fight light pollution by measuring it in your area. Collect valuable data (see globe at Night map above) on night sky brightness and submit your observations from your computer or smartphone. It's simple, fun, and educational! 




Light Pollution Videos

Watch “Losing the Dark,” a short film created by IDA in collaboration with Loch Ness Productions. “Losing the Dark” can also be downloaded for free and is available in 13 languages.

Watch astrophysicist  and IDA Dark Sky Ambassador Lucianne Walkowicz simply and engagingly explain why light pollution and citizen science projects matter.

Watch IDA Executive Director Bob Parks discusses light pollution on CBS This Morning.



Recent Light Pollution News
How Light Pollution Clouds the Night Sky (Men’s Journal)
We illuminate our driveways, porches, parking lots, storefronts, highways, and public spaces. Now the night sky is becoming an endangered species. Read more .

Light pollution eclipses more of the night sky (Financial Times)
The glory of a clear night sky is becoming more inaccessible then ever in built-up Britain as light pollution continues to increase. Read more .

Drowning in Light (Nautilus magazine)
Technology has fed our addiction to light, and might help us end it. Read more .

See Light Pollution in Action (Universe Today)
Like anyone else who’s ever looked up at the night sky in any but the smallest cities, I’ve seen light pollution first-hand. Like anyone else even marginally involved in amateur astronomy, I know about the fight against light pollution. And I know that, what with new LED lights and everything, it’s not going to be easy. Read more .

The 45 Brightest Cities in the World, Photographed By One Woman (Gawker Media)Satellites have given us a huge amounts of information about Earth-including the fact that many of our cities are so blinding lit, they're visible from space. Those radiant cities are the subject of Lux, a photo essay by photographer Christina Seely. Read more.