Why Does the Sky Glow at Night?

Have you ever noticed that the night sky is no longer inky black and full of stars like it used to be? Have you noticed the strange orangish glow that''s replaced it? The strange orangiy glow is a form of light pollution referred to as sky glow.

Sky glow is probably the most recognizable aspect of light pollution. By far the largest segment of the population equates sky glow with light pollution. This is wonderful, as it shows a growing awareness of the problem. As a quick refresher, sky glow is the glow we see above cities and towns when viewed from a distance. The intensity of the sky glow is an indication of the quantity of exterior lighting which is wastefully shining up into the night sky.

To put the problem in perspective, estimates place the cost for the US alone in the neighborhood of$5-10 billion dollars annually. This is not the sum total of all outdoor lighting, this is just that portion of outdoor lighting that is so misdirected as to light up the night sky. This is an incredible sum of money to simply waste, and yet that''s exactly what we do year after year. In fact, the problem is actually increasing in magnitude and cost.

A consequence of sky glow is the dramatic reduction in the number of stars visible in the night sky. Under pristine conditions, some 4000-5000 stars may be seen. In the most light polluted cities, perhaps a dozen or two are visible. You may think that this only impacts astronomers, but you''d be wrong. We are all affected in a profound way. The human race has looked to the stars through out history in an attempt to understand our place in the universe. It is highly unfortunate that the most technologically advanced civilization to inhabit this planet should also be the most detached from the cosmos. It is no wonder that more and more people feel detached, alone and overwhelmed in our continuous motion society. They simply have lost their reference points and are unable to find their way.

Sky glow also changes the surrounding environment. In many areas, it never really gets dark at night. This seriously impacts local wildlife. Many species are simply unable to adapt. Sea turtles are a prime example. All sea turtles that inhabit Florida waters are either threatened or endangered, and according to the Florida Fish & Wildlife Conservation Commission, light pollution is a major contributing factor.

If you''d like to change this situation, its easy to do your part. Simply choose a night sky friendly light fixture. Night sky friendly lights put all the light they emit onto the ground beneath them and do not shine any wastefully up into the night sky. By choosing a night sky friendly outdoor light fixture for your home or business, you can feel better knowing that you are doing your part to reduce sky glow in your area and help to reclaim the majesty of the night sky.

Anthony Arrigo is an avid astronomer and night sky activist. His company, Starry Night Lights (http://www.StarryNightLights.com) specializes in night sky friendly outdoor light fixtures.