By Deborah Price and Martie Semmer, IDA Colorado Board of Directors

3.8.2023

Earth Day (April 22) is a great reminder each year to protect our home planet. However, each day we have with the sun is reflected by nighttime with the moon and stars. While one half of the Earth is bathed in light, the other half is dark.

Half of life on earth is nocturnal. Many species of wildlife have evolved eyesight that is specifically designed for night vision. Light pollution is often a detriment to their survival and ability to thrive.

Night is a magical time, not only for wildlife survival and activity, but for the glorious skies we see above our heads. The darker it is, the more you can see. The more we keep lights off, the more our eyes adjust to darkness. We see better at night when there is less light pollution. Our pupils expand in the darkness and allow us to take in much more of the night around us. When lights are turned on, our pupils shut down and put a barrier between us and the magic of the night.

This year’s theme for Earth Day is Invest in Our Planet. Investment can mean a lot of things, and investing in protection of the night has some pretty simple rules we can follow. It starts with using lights only when we need them, and directing light where it is needed (not up into the sky or into a neighbor’s yard). When we find ways to protect life after dark, it helps our lives shine a little brighter in the daytime too.

Happy Earth Day (and Night!)

Earth Day: Because Every Day Needs a Night

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IDA Colorado members and others are working to find new approaches to measuring skyglow where our problem is greatest, the Front Range Urban Corridor, along a line from Pueblo, through Denver, and north to Fort Collins.  Airplane flights are being used to capture skyglow images from about 3000 feet above ground level.  The National Park Service Night Sky Team is creating their all-sky false-color images from the ground, to compare to the images taken from the airplane.  Photographers are taking conventional photographs from viewpoints in the foothills immediately west of the Urban Corridor.  And IDA members are taking conventional SQM readings at a number of locations along the Urban Corridor. 

We’re working with a variety of partners:  in addition to IDA Colorado members, other participants include Jeremy White from the National Park Service Night Sky Team, the people at Lighthawk Conservation Flying, CSU’s Dr. Kyle Horton, and leading Colorado videographer and photographer Diego Rodriguez.  If you would like to help, please contact Richard OBrien (richard.obrien@darksky.org).