Light pollution has only become a problem in the last hundred years, since the invention of the light bulb in 1879 and the growth of electrified cities, explained John Barentine, program manager of the International Dark Sky Association. He defines light pollution as the excessive use of artificial lighting, which is causing our inability to see the stars at night. This artificially produced sky luminance is steadily growing in magnitude on a global scale. According to “The New World Atlas of Artificial Night Sky Brightness,” a study documenting the impact of the broad use of artificial lighting across the globe, more than 80 percent of the world’s population has a compromised view of the night sky.

 

Dark skies advocates maintain there already exist several effective ways to reduce the amount of artificial light used each night. The IDA believes local authorities should concentrate a part of their legislative efforts to create and enforce comprehensive outdoor lighting ordinances. It also recommends the increased use of warm-white LED lights with shielding that prevents light from being projected skyward. They say this will protect humans’ view of the sky and may also reduce health issues that come from high-intensity white LED lighting.

 

Individual property owners can do their part by making sure light is only used in places where it’s truly needed, during the times of night that it’s required, and in carefully measured quantities.

 

Flagstaff was the world’s first “International Dark Sky City” designated by the IDA in 2001, even though the city started reducing its light use in the 1950s. The city has outdoor lighting ordinances meant to encourage people to be mindful of the amount of light they emit. 

 

Anne Wittke, a Flagstaff resident and Coconino Astronomical Society member, said both municipalities and individuals could make greater use of adaptive controls, such as timers, motion sensors and dimmers to reduce the intensity and amount of time artificial lighting is on.

 

Proponents of more rather than less light claim that outdoor lighting greatly aids in deterring crime, making residential areas and businesses much safer. A recent Phoenix Police Department home security evaluation suggests residents keep the outside of their homes well lit. The evaluation notes leaving exterior lights on during the hours of darkness can reduce criminal opportunities when used in conjunction with other security measures, such as keeping shrubbery trimmed, having adequate security doors, monitored alarm systems, etc. 

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But some Phoenix neighborhood associations argue that adding light to a previously unlit space doesn’t seem to have a marked effect on reducing crime. In some instances, introducing light to places where it didn’t already exist may actually encourage criminal activity because it can readily expose to any thief exactly what there is of value to steal – which runs counter to the commonly held view of area illumination as a strong and effective deterrent. 

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Both parties agree timers and motion-activated lights are the best practices for keeping residential areas safe, especially when used in conjunction with those other security measures mentioned above. 

 

“Preserving dark skies and enabling the continued science of astronomy is very important to the state of Arizona,”said Alan Strauss, director of the University of Arizona’s Mount Lemmon SkyCenter (MLSC) located in Tucson.

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Astronomy is an industry that has had a significantly positive impact on the economy in Arizona, according to Strauss. A study conducted in September 2007 by The Arizona Arts, Sciences and Technology Academy concluded the astronomy industry was successfully generating approximately a half billion dollars for the state’s economy every two years – roughly the same amount the Super Bowl brought to Arizona when it was last held here in 2015.

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“Astrotourism” is one outcome of the astronomy industry that clearly has played a major role in this economic success story. About 75 to 80 percent of the people who visit the Mount Lemmon SkyCenter annually are tourists. Many come from larger American cities or abroad, and when they visit, it is quite often their very first time experiencing live views of several features of the Milky Way without the visually obstructive interference caused by light pollution. 

 

Professional astronomers, as well as dark sky enthusiasts like Strauss, have dedicated themselves to demonstrate to the public what they are truly missing through educational facilities like the SkyCenter, where people have the unique opportunity to experience some of the many wonders of the universe through an enhanced level of stargazing.