National Geographic Daily News
Chicago at night burns bright under blankets of clouds.

An aerial view of Chicago at night.

Photograph by Jim Richardson, National Geographic

Paul Bogard

for National Geographic

Published July 19, 2013

We live immersed in artificial light.

Astronomers rate the darkness of our skies on a scale (the Bortle Scale) of 9 (brightest) to 1 (darkest). Most of us spend our lives in the radiance of levels 5 through 8, only rarely venturing into areas ranked 3 or darker. Because of the rapid growth of light pollution over recent decades, most Americans under 40 have never known real darkness. All over the globe our nights are growing brighter, and almost nowhere are they growing darker.

We are just beginning to learn the true cost of all this light. Studies increasingly link our overuse of light at night with health concerns such as sleep disorders, diabetes, obesity, and cancer. Other studies report the damaging ecological consequences, the tremendous waste of energy, and even the decrease in safety and security. But the steady loss of darkness from our lives is not easily quantified, for like the similarly endangered qualities of solitude and quiet, the true value of darkness is often intangible.

Take a brilliantly starry sky. Since the beginning of time, a sky plush with stars was part of the common human experience. Everywhere on Earth, on most nights, our ancestors came face to face with the universe. This experience influenced their religious beliefs, mythologies, art—their very understanding of their place in creation. Today, because of light pollution, two-thirds of those in the United States and western Europe live where they cannot see the Milky Way, and 99 percent of us live under skies polluted by light.

For the tens of millions who live under a night sky showing 25 stars or fewer, it is nearly impossible to imagine a natural sky of some 2,500 individual stars backed by great swathes of uncountable billions. Our night sky continues to shape us, but now it is the absence of the universe around us that influences our religious beliefs, our myths, our impulse to create. We are being shaped by a diminished experience of darkness, and most of us don't even know what we are missing.

Imagine the world without van Gogh's "Starry Night," Chopin's "Nocturnes," Beethoven's "Moonlight Sonata." Imagine the world without the astral myths of the Greeks and every other ancient and primitive civilization, without countless biblical stories that rely on darkness, without St. John of the Cross's book Dark Night of the Soul. Imagine the world without the gathered inspiration of countless generations before us looking into the night sky and being filled with wonder, with questions, with desire to know and understand. Most of us have lost this opportunity to be awed at the sight, to feel similarly inspired—to create, to change our lives, to gain a greater understanding of our God.

Our Milky Way galaxy is home to several hundred billion stars, and the universe home to several hundred billion other galaxies. Because of light pollution we no longer have a nightly reminder of how small we are, nor of how large. A sky wiped clear of stars tempts us to inflate our importance, to imagine humanity as the center of all things. Face to face with the endless immensity of the universe, we have the chance to know humility. But we might also realize the true largeness of our living on this beautiful Earth, and realize that we have an enormous responsibility to care, that there is no other place to go, that home is here.

Night's natural darkness can teach us about metaphorical darkness as well. Ancient cultures included in their hero myths an experience of the dark—the dark wood, the underworld—for to become fully human was to acknowledge darkness as part of life's journey. It certainly is today—we often live in the darkness of not knowing, unable to see the future, with no crystal ball. Genuine faith isn't about finding clarity, but rather living with doubt. Those who profess to have no doubt, to have all the answers, to believe theirs is the only truth—they ignore the reality of metaphorical darkness. All life on Earth evolved in both bright days and dark nights, and we need both for optimal health. This is as true for our spirit as for our body.

And what of beauty? "Everyone needs beauty as well as bread," wrote John Muir, and darkness is rich with this intangible resource. Lighting designers in Paris understand that without darkness, there is no "city of light," and work constantly to create their city's atmospheric beauty by subtly mixing artificial light with darkness. And with night's moonlit geographies, its scents of sage-infused desert rain and autumn fires, its pulsing cricket symphonies punctuated by a loon's solo call on a northern lake, natural darkness offers endless beauties of its own.

Yet we live immersed in artificial light. Much of this lighting is wholly unnecessary, born of habit and lack of awareness. So let us become aware: Simply by shielding our existing lights we could significantly reduce their negative effects on our body, our mind, our soul. Artificial light at night is a miracle, a wonder, a quality that enriches our lives. But the same has always been true of darkness, and can be again.

Paul Bogard is the author of The End of Night: Searching for Natural Darkness in an Age of Artificial Light, which was published this month.

Patsy Powell
Patsy Powell

So True !

I to believe that to much light is wasted.. IT generates HEAT ! That type light is studied an proved to make cancer cells grow. The energy that they ar produced from can make Polution of Smoke heat, from coal heat, gas heat, nuc...lear heat. Constantly day an night, is eating the ozone. Then all Rockets into spae, HEATed in one place to much heat by JEt Fuels.. PEOPLE are Destroying the WORLD ! I have noticed here in Mississippi, an Alabama, people are cutting back on light useage. Whether to save energy, or their pocket book cash to bills? Not sure.. but its a cut back of lights in the night.. @ car lots also did so.. while others could land a martian ship as a airstrip so bright.To ME I think many should have solar light that are on sensor.. I SO love dark, dark, to sleep in.. When all are keeping lights on all day an night..YA have trouble sleeping. An Sleep IS Essential ! For all things ! God said HE separated tHE LIGHT DAY, AN the DARk night.. HE Seperated for a REASON ! MAn has Unseperated What God said was too be !


Love the video.>BEautiful

Madiha S
Madiha S

I went to camp after a long time a few years ago and I casually looked up at night through an opening in the trees and I was astonished. There were so many stars just in that small space and I remember asking: are there always this many stars!? I definitely wish that I could get away often and just sleep under the stars. I have also yet to see the milky way.

First Last
First Last

"Studies increasingly link our overuse of light at night with health concerns such as sleep disorders, diabetes, obesity, and cancer." But what is the actual "link"? And in any case, anyone concerned about this supposed link can just turn off the lights inside and pull the curtains. It's silly to conflate this with light pollution. Put this article where the light don't shine.

Shyam Pandya
Shyam Pandya

A starry night is rare to see in cities. The brightness of a full moon too is also rarely noticible in cities. Perhaps the "Earth hour" should be done more often.

Shreenivasan Manievannan
Shreenivasan Manievannan

Basically from a light polluted city of Chennai India, I was astonished when I eventually came face to face with the Milky Way in a remote location in Utah. Light pollution is definitely a curse on us to make us miss the shear briliance of the night sky. I went on creating some photographs of the night sky to convey a message that may not seem too important in this fast paced world.

Sagar Talluri
Sagar Talluri

Being part of a developing nation, I have grown to see light pollution take away a small part of my starry sky every night.
We now go and pay $$ to see movies in HD/3D/IMAX etc, when, all we needed was to look up at night and be awed each time. 
This so called "Development" is a high cost to pay to lose the universe! 

Carsten Angerhofer
Carsten Angerhofer

Last fall, I went camping with some of my friends in the San Rafael Swell in the desert of Southern Utah. We decided to sleep under the stars and a few of my friends were shocked when they saw the Milky Way for the first time. Even though we are all college students, they had never seen it and didn't even know what it was.

Light pollution is a tragedy.

Carol Music
Carol Music

Having been blessed to have grown up in the late 40's and 50's, I clearly remember sleeping outside in the summer and just marveling at all the stars, meteorites and very occasionally then, in Western WA, the Northern Lights. Then it would just be a moving mostly white light. I loved looking at the Milky Way and finding the Big and Little Dippers and being so amazed and awed at what we now know as the Perseids Meteor Showers. It was all magic to us, but I continue to love seeing photos of all those. I think it's very sad that today's young adults and kids rarely if ever get to experience those phenomena, as well as, according to the article, making our lives less healthy. We live in the country now, but there are street lights and traffic which greatly reduces the visibility of the universe at night. A true loss.

Audrey Fischer
Audrey Fischer

@First Last The actual link is circadian disruption of nearly all life forms on this planet that evolved for eons with a pattern of day and night, plus seasonal cycles.  This "suddenly" changed about 120 years ago... and even more-so in the past 2 decades.  This is much to soon  without serious consequences.  This affects humans, the environment, ecosystems including the food chain and pollinators, bird migration,budding of flowers & trees,  wildlife production, and an endless list.  Let's take the CO2 levels.  Nitrate radicals evolved in such a way that they "eat up" the air borne pollutants accumulated in the daytime -- however the catch is, they are triggered into action by darkness.  No dark - no cleansing.  Therefore the CO2 levels are higher in the morning directly because of light pollution.  Nature and wildlife cannot pull the curtains and shut the blinds. Please do the research.  You will find it interesting if you really want to find the truth.  We are needlessly harming nearly all life on this planet out of stupidity and stubbornness, with a touch of laziness and self-centeredness. We can have starlight and streetlight in cities.... IF we make the right choices.

Robert Lupoiu
Robert Lupoiu

@First Last I am guessing that the "link" is that since more lights mean we are more and more advanced, then more and more people will be diagnosed. I don't think it has anything to do with the lights, but more with the greater awareness towards these diseases that comes with time.  

Audrey Fischer
Audrey Fischer

@Robert Lupoiu @First Last   Hi Robert, At first look, it is not intuitive that light pollution could possibly cause serious and deadly health concerns.  At first, I doubted it myself, but as a person with a cancer history that nearly took my life at 19, I decided to look into it seriously.  The research is undeniable.  Artificial light at night shuts off your natural melatonin flow and seriously disrupts the circadian.  Even the tiniest of cells respond to the circadian signals independently.  Bottom line, light at night (other than dim red or amber) really does have a direct link to increased risk of breast, prostrate, colon cancers; type 2diabetes; MS; sleep, memory and mood disorders including depression... and more.  Research has just scratched the surface.  In the meantime, sleep in a dark room or use a sleeping mask, (as the signals are received in one of the ganglionic cell layers of the retina -- so your whole body does NOT have to be in the dark.  Please, do what i did.  research it.  search: melatonin, cancer, circadian disruption, dr david blask, dr george brained, dr richard stevens... just to get you started.  the risks are very, very real.  It is pitiful that these risks have been known for decades and it gets ignored.


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