Reclaiming the Milky Way, allowing our eyes to work
—Stephen M Pauley, MD
While driving, ever notice how relaxed we become after we leave the bright city lights and drive onto a dark country road? Our grip on the steering wheel eases, our muscles relax, and overall we feel more comfortable.
The reason? Our eyes are being allowed to work as nature intended. Our pupils dilate and adapt to the lower light levels. Contrasts become much more distinct. We’re guided along our way not by glaring street lights but by our headlights, the reflecting stickers attached to posts at the sides of the road, and the reflectors that are often embedded in the pavement.
Compare this to city driving. Our eyes are assaulted by bright and competing light sources. Our pupils constrict to adapt to the brightest of these lights, and our ability to see in the shadows is nonexistent. We are far more tense and more prone to becoming impatient and discourteous drivers. The glare is always annoying and at times dangerous, especially for the elderly.
You and I were born into a world that has robbed us of the night’s darkness. In the last hundred years modern societies have turned the darkness into daytime. We’ve created an unnatural environment that competes directly with the way the human eye evolved. Half of what we see in our world lies above the horizon, in the skies above. But we’ve stolen that half away from our children and ourselves.
Since the first mammals appeared 270 million years ago, the eyes we see with today have evolved into exquisite organs capable seeing under a wide range of conditions—from the extremes of bright sunlight to the star-filled darkness of a moonless night.
Three million years ago, our hominid ancestors (Homo erectus) hunted food in the dark, gave birth in the dark, and sustained themselves without artificial light. Two million years ago early man most likely huddled around the light from fires on the African plains. Digs in China reveal that Peking Man used cooking fires about five hundred thousand years ago. Caves in France reveal the first evidence of use of candles by Homo sapiens, twenty thousand years ago. Small stones were hollowed out to form shallow basins which held animal fat as fuel, and rolled vegetable matter was used as wicks for a flame. Cave art was made possible using the light from those dimly lit stone candles.
Our ancestors timed their lives by the stellar landscape. Those who learned to predict solar and lunar eclipses became powerful leaders. They built monuments that marked the solstices and equinoxes—the earliest clocks that celebrated the passage of time and told people when to plant crops. Visual awareness of the cycles of stars, the Sun, and the Moon played a vital role in turning early hunter-gatherer groups into community groups who shared resources and built the first cooperative settlements. Today we are virtually disconnected from the natural awareness of the night sky that was so important to our ancestors.
Thousands of years passed before we began to light up our city streets, first with candles, which were soon followed, in the early nineteenth century, by oil lamps, coal-gas and natural-gas lamps, the carbon-arc lamp, and the kerosene lamp. Street lighting in those days was still dim enough to allow our eyes to work as intended. We could still use the light-collecting rods in our retina, which developed through millions of years of human evolution, to see the stars.
An abrupt end to our nighttime seeing came with the invention of the carbon-filament light by the Englishman Sir Joseph Swan. When Thomas Edison commercialized the carbon-filament light in 1879, the lighting industry was born. Tungsten eventually replaced carbon, and thus began the slow, insidious process of turning the darkness into daytime.
For the past hundred years, lighting companies, utility companies, national, state, and local governments, and now gas stations, commercial centers, and convenience stores, have set their own agendas about what’s best for us during the dark hours of our lives. They have played on our insecurities, and our fear of crime. They have convinced us that our cities and towns look more attractive when lit up at night, failing to consider the consequences of all that light.
While no study confirms that more lighting reduces crime, we’ve been led to believe that it is so. The reality is that more lighting simply gives us the feeling of security, not more actual security. This misperception explains, in large part, the past one hundred years of inappropriate outdoor lighting. “Security” lighting has become a euphemism for advertising. Humans are likened to moths attracted to a flame.
Because you and I were born into this over-lit nighttime world, we don’t give it much thought. Half of our country’s population has never seen the Milky Way, so what’s there to miss? But now there is a movement in this country and in other countries around the world to restore the dark night skies and to allow our eyes to reclaim the Milky Way.
The International Dark Sky Association (www.darksky.org) is leading the way to educate America and the world on better lighting. IDA’s message is, We can safely reclaim the darkness by using light far more efficiently. It’s done by using full cut-off street lights, area lights, and yard lights, and shielded flood lights. These can reduce urban sky glow, eliminate annoying light trespass onto the property of others, and diminish dangerous glare. Using these outdoor-lighting concepts, we can reduce the nation’s annual $1.5 billion cost of shining wasted light up into the sky and reduce electric bills for local governments, businesses, and homes. And not having to burn the extra fossil fuels (oil and coal) that generate the wasted light cuts down on greenhouse gases and global warming.
Need for Lighting Ordinances
A caution: without local and statewide lighting ordinances, we will have to endure another century of even worse outdoor-lighting practices. Instead of repeating those bad habits, let’s now work for ordinances that require full cut-off lighting, no lighting at all where appropriate, and reasonable gas-station, convenience-store, and parking-lot lighting.
Let’s make one of our goals for the children of the next century a return to the pleasure of viewing a star-studded night sky. Let’s begin to think of the dark sky as the precious natural resource that it is. Let’s allow our children’s eyes to reclaim the Milky Way.
For more information, including tips on how you can shield the outside lights at your home, please visit www.darksky.org.
Dr. Pauley is a retired ear, nose, and throat surgeon living in Sun Valley, Idaho. He is an amateur astronomer and celestial navigator. He also works with Idaho Rivers United to prevent extinction of salmon and steelhead in the Northwest and does volunteer surgery every year in Ecuador.