"Darkness is as essential to our biological welfare,

to our internal clockwork, as light itself."

— Verlyn Klinkenborg, Our Vanishing Night in National Geographic

If, like most people, you live in a city, it's unlikely you can see the gossamer expanse of the Milky Way. It's possible you've never spotted it at all. For most urbanites, the night sky is a pink glow broken only by the moon, the brightest stars and passing airplanes.

This is the form of pollution most people have forgotten: light pollution. And while undark skies may not rank in importance alongside the chemical trash we routinely dump into the atmosphere, the continuous, unblinking glare of modern life is not without its impact on wildlife, dwindling energy resources and human health.

What's the big deal about light pollution?

As the sun begins the rise, the lights are still shining. moogan/Flickr

Light pollution is so widespread, so universal, so common to urban life that we hardly give it a thought. Set poetry aside for the moment — the great severing of our ancient connection to the constellations as they wheel gently through night and season. We are still confronted with four specific areas of concern regarding light pollution:

Light pollution interferes with wildlife migratory and breeding patterns.

Unnecessary outdoor lighting wastes energy and contributes to greenhouse gas emissions.

Glare from bad lighting leads to unsafe driving conditions, particularly for older motorists.

Constant exposure to artificial lighting may interfere with human metabolism and sleep.

These problems are sufficiently severe that the American Medical Association voted unanimously in 2009 to support efforts to control light pollution.

Here are five things you can do to help curb light pollution:

1. Start with the light switch. The cheapest, most obvious and most effective way to reduce light pollution is to start turning things off. While there's a time and place for outdoor lighting — illuminating after dark activities, for instance — many of us burn porch and spot lighting because it gives us a sense of security. In fact, there's little data to support the idea that outdoor lighting reduces crime. Turn on lights when you need them, or use portable lighting. Go dark when you don't.

2. Check with your power company to see if you're paying for outdoor lighting. It's possible you're being billed for that nasty sodium vapor lamp down at the street. Many utilities charge $5 to $10 a month for this service. A quick check of your bill or a call to customer service will tell the story. If this turns out to be the case, terminate the charge and ask that the light be removed. Most power companies are happy to oblige.

3. Consider replacing outdoor lights with intelligently designed, low-glare fixtures. Did you know there is a certification body for sky-friendly outdoor lighting? The International Dark-Sky Association evaluates fixtures for low glare and efficiency. Look for the IDA seal of approval on locally sourced fixtures, or seek out a company such as Starry Night Lights, which specializes in low-pollution lighting.

4. Place motion sensors on essential outdoor lamps. Lighting on demand trumps a manual switch or timer. Motion sensitive switches will light up porches and walkways when you need to move around after dark. They'll pay for themselves in fairly short order.

5. Replace conventional high-energy bulbs with efficient outdoor CFLs and LED floodlights. While efficiency lighting won't directly keep all those stray lumens from bouncing around, it will take some of the sting out of your monthly bill and reduce power company carbon emissions. Just don't fall into the trap of thinking that CFLs and LEDs are an excuse to be sloppy about switching things off. While you're at it, see whether low-wattage, solar powered walkway lamps might replace area lighting. They're inexpensive and practically free to operate.

Now, enjoy the darkness!

Once you've switched off your lights, more objects will come into view. peresanz/Shutterstock

You'll be surprised how much squelching a few bulbs around your home improves the view. Why not take this opportunity to get reacquainted with the nighttime sky? You don't need a telescope to see the major constellations, bright nebulas, open clusters, many of the planets, comets, meteors and dozens of man-made satellites and spacecraft.

It's not difficult to learn the ropes. If you're feeling old school, buy a simple star wheel. For easy pointers on nightly backyard observation highlights, try Sky and Telescope's The Week's Sky at a Glance. To spot orbital objects, such as the International Space Station, the Hubble Space Telescope, and a galaxy of satellites and discarded rocket boosters, create an account at Heavens Above (be sure to customize it for your location). And you can use your computer as a virtual planetarium with Stellarium, a free and full-featured 3-D program that runs on Mac, Windows and Linux.

A set of inexpensive binoculars will expand your star-spotting capability. But all you really need is the desire to look up into the wonder of the night — and the blessings of a dark sky.

This story was originally written for Lighter Footstep and has been moved to TreeHugger. Copyright Lighter Footstep 2009