Time to see the light on dark skies

[plain text]

© AZ Daily Sun Sept 16, 2006

By DAVID S. F. PORTREE

Coconino Voices

The night sky makes a major contribution to northern Arizona's economy. The U.S. Naval Observatory, Lowell Observatory, and Northern Arizona University all look to the cosmos in quest of knowledge. In doing so, they have contributed millions of dollars to the local economy every year for decades. It's not surprising, then, that the City of Flagstaff and Coconino County have enacted lighting codes to protect this enviable economic boon.

Northern Arizona also has its share of amateur astronomers, people with a passion for cosmic wonders. They range from casual stargazers to near-professionals with costly personal observatories. These hobbyists revel in the beauty a dark night sky reveals. Many take pains to share their enthusiasm with others, providing educational opportunities for northern Arizonans.

So dark skies are good for Flagstaff. Looked at globally, however, the night makes only a modest contribution. Even in Arizona, which has more professional telescopes per capita than any other U.S. state, astronomy probably accounts for no more than one percent of the economy. Millions of people in large cities -- including Phoenix, Arizona's capital -- can view only the brightest stars, but that doesn't seem to cause them any harm. If they decide that they need a night sky fix, they can drive to Flagstaff and spend some money here -- right?

So, in the big picture, does it matter if people light up the night sky?

Lighting our homes, businesses, roads, and parks costs money. The Tucson-based International Dark-- Sky Association estimates that bad outdoor lighting -- that is, lighting that throws light in all directions, not just where it's needed, and which compensates by being too bright for its purpose -- costs Americans $1 billion per year in wasted energy. This figure is probably a gross underestimation.

Wasting energy usually means wasting fossil fuels. Burning more gas, oil, and coal than is necessary means putting more carbon into the air than is necessary. Atmospheric carbon acts like greenhouse glass, holding in the Sun's heat. Carelessly lighting the night thus contributes to the warming of the world. If you have unshielded, glaring outdoor lights -- and most of us have at least one -- then you are needlessly contributing to a global environmental problem that has serious implications for humanity's future.

Even if you don't believe that global warming is real, it still makes sense to spend less of your hard-earned dollars on energy.

Reducing our personal dependence on fossil fuels is hard if we have a normal American lifestyle. That's what makes controlling light pollution so attractive -- it's something that almost any of us can do, with nothing but positive impacts on our lives.

Replace a glaring, unshielded light fixture, and you'll accrue the benefits of reduced energy costs for years to come. Better lighting tends to make your property look nicer, too. You'll get that warm feeling that comes from helping to save human civilization. And you'll make some stargazers happy, too.

******************

David S. F. Portree teaches astronomy on the Navajo and Hopi reservations. Though he is writing three books, he finds time to admire Flagstaff's dark night sky -- that is, when his neighbors' unshielded outdoor lights don't interfere.