Light Pollution

We have all encountered pollution, in the air we breathe, the food we eat, the water we drink, and the sea we bathe in. There is the neighbor's hi-fi, and the noise from motor bikes, pneumatic drills, and low-flying aircraft; but what is light pollution?

Light pollution is unnecessary excessive light that causes annoyance to others. It can take one of three forms: sky glow, seen over major cities; glare, the uncomfortable brightness of a light source when seen against a dark background; and light trespass, the encroaching of light beyond the boundary of the property containing the source. It can deprive someone of sleep when a bedroom is illuminated by outside light, and it can and does rob us of one of the most awesome and beautiful sights in all nature, the starry night sky.

The first type of light pollution is obvious. While some people can sleep undisturbed in bright illumination, many find that light pollution does affect their rest. This is especially so if the light is intermittent, such as a flashing beacon or advertising sign. The source of light pollution does not have to be nearby, a powerful light in an otherwise dark area can strongly illuminate rooms at some distance and be a cause of annoyance.

The second type of light pollution is now scarcely recognized, because very few who have been brought up in an urban area have ever seen the glories of a night sky free from light pollution. It is sad that most people just do not know what they are missing. However, those old enough to remember the wartime blackout, or anyone who has enjoyed a camping vacation far away from civilization, know full well what a night sky can look like, and mourn its loss in the baleful, orange streetlamp glare that surrounds our cities at night.

Astronomers in particular bewail the effect. Astronomy is now not just a small minority interest, a growing number are taking it up and acquiring telescopes and other equipment to explore the night skies. But observation of distant galaxies and other faint objects is bedeviled by the ubiquitous orange glare of light pollution.

Little can be done by the ordinary person to reduce light pollution caused by streetlights other than lobbying of local governments. Some enlightened city councils are aware of the problem posed by light pollution and are implementing recommendations by the Institution of Lighting Engineers.

Some of the most spectacular views of the stars are available in northern Arizona. Those who've spent a night at the Grand Canyon will never forget the colorful large canyon that is one of the natural wonders of the world but they'll also remember the spectacular starry skies at night free of light pollution. The nearby city of Flagstaff bills itself as the first city of lights and severely restricts light pollution.