The Great Vanishing Act (of the Night Sky)

Ever drive out into the countryside and marveled at the big strip of the Milky Way arching across the sky and thousands of stars shining everywhere, then wondered why you couldn’t see that from downtown Geneva or from your own driveway? No, the air is not clearer. There’s simply less lights.

The Author, His Telescope and the Milky Way, Cherry Springs State Park, PA

The Author, His Telescope and the Milky Way, Cherry Springs State Park, PA

The splendor of the night sky is all but invisible from most of the places we tend to live and congregate because of what’s called light pollution. Roughly defined, light pollution is too much light in general and light needlessly shining where it is not wanted.

The cause of light pollution is bad lighting design. For the most part, we put lights outdoors to illuminate what’s below them: walkways, parking lots, streets, driveways, and doors. Yet most outdoor lighting shines in every direction: out the sides and even up. The sideways light causes glare, which makes it harder to see anything at all at night, and light trespass, light that shines where it’s not wanted, like in your bedroom windows at night. The upwards light causes sky glow, an orange haze over heavily lit areas that hides the stars and Milky Way.

All these components of light pollution have real life consequences. That’s why we call it pollution. And it’s a global problem. In a November 2008 cover story, National Geographic reported that 1/5 of humanity (that’s over 1 billion people) live in skies so light polluted that they cannot see the stars and the Milky Way. 2/3 of humanity (that’s 3 billion people) suffers some kind of light pollution. It’s bound to get worse. Our race just recently turned a corner; just over 50% of all humans alive now live in cities. As these cities grow and develop, they’ll get brighter. And the night sky will cease to be a source of visible wonder for most humans.

According to the experts, here’s why light pollution is bad:

• It disrupts melatonin production in humans, which messes with our sleep cycles. • It makes driving at night way more dangerous because of glare, which makes it harder to see anything but the bright lights. This problem is worse with older drivers. • It disrupts the normal cycle of hormone production in women, which puts them at greater risk of breast and other cancers. • It kills 100 million birds a year because they collide with lighted buildings and towers. • It disturbs the reproductive cycles of frogs (kermitus interruptus) who are already dying off worldwide for unknown reasons. • It hurts sea turtles, who can’t find dark beaches to lay their delicate eggs.

The American Medical Association (AMA) just declared light pollution a public safety and health hazard, citing the above reasons as well as the 2.2 billion dollars a year we waste on lighting things we don’t intend on lighting (like the night sky.)

The solution to the light pollution is unbelievably simple. It’s better lighting design. Most outdoor lighting (like the irritating “old fashioned looking” globes that line downtown Geneva or HWS campus) are non- or semi cut-off fixtures. Common streetlights are the latter. They don’t shine line up, but they do shine a lot of light sideways.

Full cut-off lighting only shines light down, where we really want it. You can’t see the bulb itself (unless you are under it) but you can see what it is supposed to light up. These lights don’t need to be as powerful since all the light is going where we want it, so that saves money over time. The city of Calgary, Canada, saved over 1.7 million dollars a year in energy costs when it switched its streetlights to lower-wattage, full cut-off designs.

One of the reasons often cited for not solving the light pollution problem is safety. The more lights, the better, and everywhere, the argument goes. Let’s not give crooks and rapists shadows to hide in, the argument goes. Let’s light up the roads so that drivers can see.

Bad lighting actually makes the situation worse. Take two flashlights and go outside. Shine one at your face and one at your car. Can you read your license plate number? Now shine both of them at your license plate. That’s better, right? That’s how full-cut off lighting works to make your nighttime safer and your night sky prettier.

You can help solve the problem yourself. Next time you’re changing or adding a light fixture outside, choose a full cut-off design. You’ll sleep better at night, perhaps literally.

The problem is also solvable at the municipal level as well. Many cities, like Calgary, Canada, and Flagstaff, Arizona, have enacted dark sky ordinances that essentially call for all newly installed outdoor fixtures to be low-wattage full cut-off designs. Some communities have grandfathered in existing fixtures but stipulated that when they are replaced, full cut-off designs are used.

Having visited Flagstaff this July, I can tell you that it’s a pleasure to drive there at night. You see the roads but not the glaring streetlights. And from the middle of the city, you can see the Milky Way!

There are a lot of reasons to solve the light pollution problem: economics, the environment, public health and safety. But let’s not overlook an important but immeasurable benefit of the night sky. Our window to the universe is critical to the development of the human mind and the cultivation of a far-seeing wisdom. I see the effect of it every time I let someone look through my telescope. I saw it this summer out west, in National Parks that have fought hard to preserve their dark skies. The starry night changes people’s behavior; it stops and makes them think, and we need more thinking. It gets people talking in wonder together, and we need more community. We need the natural world—and the night sky represents the part of that world that is most challenging to our understanding—to inspire us and humble us in a way that no computer generated graphic ever can.

You can learn more about light pollution…online, of course. Visit the International Dark Sky Association webpage for lots of infomration:


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