"Don't it always seem to go
That you don't know what you've got til it's gone
They paved paradise and put up a parking lot."
When Joni Mitchell wrote "Big Yellow Taxi" 30 years ago, she managed to capture a big idea in a few simple lines.
"They took all the trees and put 'em in a tree museum.
And they charged all the people a dollar and a half just to see 'em ."
The trees lost served as a poetic metaphor for the destruction of natural places and the loss of natural beauty in our lives. But Mitchell probably never imagined it might apply to something as immutable and beyond our reach as the night sky itself.
Dramatic change can come quickly, even all at once. More often, however, it seems big changes come gradually, a little bit here, a little bit there. So slowly it is almost imperceptible. When that is so, perhaps it would be more accurate to say "that you don't know what you had when it's gone."
So it has been with many things. Changes happen over the years, over decades, over generations. And often, we don't even know what we are missing.
For many years, Frederick was small enough and far enough from big cities to provide something special - even stunning and inspirational - with only an upward gaze on a clear night. But the Washington and Baltimore areas have gotten bigger and closer and brighter, and Frederick and other towns in the county have gotten bigger and brighter, too.
We are losing - have lost - something people for almost all of time have taken for granted. Other than astronomers - and a few poets - most of us probably haven't given much thought to light pollution. But, children in Frederick County are well on the way to joining the three-fourths of Americans who grow up without being able to see the Milky Way. The wonders of fireworks and laser light shows, and the glow of television sets and video games, are replacing the natural wonders of a star-filled night sky for children today
We are all-too-familiar with the concept of air pollution or water pollution. And, though we might disagree about some of the particulars, virtually everyone supports efforts to protect our air and water, and ourselves, from those sources of pollution. We've also become familiar with the notion of noise pollution. We recognize that noise can be a public nuisance, even a health hazard. We put mufflers on motors. We build sound barriers along highways. We establish noise limits in workplaces and parks and neighborhoods. And so on.
We ought pay attention to the issue of light pollution, too.
Light pollution is the upward and outward distribution of light where it isn't intended or isn't needed. Light pollution can be the glare of direct light that makes it hard to see or causes discomfort. Some light pollution can be described as light trespass, which refers to light shining on neighbors when that light is intrusive or objectionable. Sky glow refers to the overall glow that comes from towns, cities, and other developed areas.
It's not simply a matter of aesthetics and star-gazing, either. A growing body of scientific research is revealing that light pollution, or the lack of darkness, is associated with a wide range of other significant problems affecting natural systems and human health, too many to describe here.
But there's good news about light pollution.
Because light pollution is really a symptom of waste, most of the solutions to the problem make good sense for many reasons. It’s a win-win situation. Perhaps as much as a third of all the light we produce is complete waste. We are paying to shine lights we want where it doesn't serve our purposes. In addition to reducing light pollution, using more efficient lighting reduces energy consumption. That reduces the direct cost of lighting, as well as the consumption of other resources, like coal and oil, and the generation of all the air and water pollution that comes with it.
Separately, it might be a good idea to ask how much of the light we use is really necessary, even when we produce and use it efficiently. For example, do we need bright security lights on all night where motion-sensitive lights will do? Do we really need to illuminate gas stations and convenience stores at levels that are 3 to 10 times the levels recommended by Illuminating Engineering Society of North America?
We are fortunate that light pollution is a lot different from PCB pollution in our rivers or CFC pollution in the upper atmosphere. When we use lights more efficiently, or turn them off altogether, the light pollution ends. There is nothing left to clean up.
Even if and when we change all the activities and reduce the pollution that has diminished the Chesapeake Bay, it will take generations to restore something resembling what was once there.
But the starry sky is still there, unchanged. We just can't see it.
So, when you are fortunate enough to be in a place where it is still dark enough to see the entire sky shimmering with stars, think how much less beauty there would be in Frederick County without it.
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