A World of Light Pollution

June 9, 2009
When most people in the city look up at the stars, they see the stars. However, many people don’t realize what they’re missing. The sky was much more starrier even 10 years ago. The revolution has completely changed our world. Among the changes brought by the industrial revolution was electric lighting. “light pollution” is a commonly overlooked problem. “Light pollution”, goes by other names, such as, “photopollution” and “luminous pollution”. These terms, all for the same thing, are used to simply describe pollution of excess artificially created light. The artificial light shinning in our world today, is the cause of many problems Earth’s denizens did not face before.
Many are unknowing witnesses to really how much their front porch lights and other city lights affect the world. At night, the world’s lighting system can be seen from space, like some sort of worldwide freak circus; an oversized Petri-dish of glowing threads spanning cross a spherical void, which is the night side of the Earth. One study concluded ten years ago that nearly the entire eastern half of the United States sky was at least twice as natural Earth’s night sky’s brightness. In some urban areas, the skies above them were said to be twenty-seven times as bright as the natural, according to an article published in Popular Science magazine by Matt Ransford.
The U.S. Census Bureau predicts that the U.S.A. will have a population of approximately 306 million at the time I am writing this. The bureau also predicts the current world population to presently be in the ballpark figure of 6.8 billion. The world population has been growing at an exponential rate for the last several thousand years until present time. Without a doubt, the night sky shines bright with people’s electric lights. As seen from space, night lighting spreads like a true virus.
Astronomy is immensely affected by artificial lights. People used to be able to clearly see a visible arm of the Milky Way by naked eye. Nowadays, old books and pamphlet might say one is supposed to see the Milky Way Arm, but it would actually be very difficult if someone tried today. A lot of our inability to see the skies without the aid of telescopes is easily dismissed. ‘Perhaps the Milky Way is just naturally too difficult to see’, or maybe clouds and/or air pollution from nearby industry and commerce is what masks the heavens above. The truth of the matter is that light pollution is one of the top contributing factors to star visibility.
You can use a telescope to see the stars, but even the telescope’s improved views are being blotted out as well. Most stargazers who make a profession of it know about the effects of light pollution on telescopes. It costs millions of dollars to construct each large telescope. Light pollution is now decreasing the effectiveness of Earth surface telescopes. Telescopes, like the Hubbell telescope are less affected. An example is the effect of light pollution at the Mt. Palomar Observatory. Mt. Palomar is located near San Diego, California.
If you are already familiar with light pollution affecting astronomy, or have noticed the effects yourself, I would like to share with you the many other effects of light pollution.
I have noticed that in the fall, city trees are still covered in leaves when the first snows fall. Many rural trees will shed their leaves much sooner than counterpart city trees that are several miles away. Leafy branches break more often under the snows weight. Why is it that city trees tend to keep their leaves? Well, one theory some have is that the artificial light produced in cities has an effect on delaying trees winter hibernation “instincts”; this causes them to keep their leaves longer, and become snow damaged.
The seemingly innocuous number of moths fluttering around artificial lights has cumulatively killed off very large moth populations. Moths expend themselves continuingly flying around artificial lights. Certain species of bat find moths easier to catch clustered around light sources. Birds also prey in a similar miner to the bats.
Some species of bat are also are suffering losses due to the concentrated feeding grounds. Many sources say certain predators are now dominating competing species due to large amounts of artificial lighting being present, such as caused by the development of rural areas. According to [name of author] of National Geographic Magazine, “In some Swiss valleys the European lesser horseshoe bat began to vanish after streetlights were installed, perhaps because those valleys were suddenly filled with light-feeding pipistrelle bats.”
The International Dark-Sky Association’s website (www.darksky.org) provides information for a partial solution: “German scientists G. Eisenbeis and F. Hassel found that various lights attract insects differently. Sodium vapor lamps reduced the attraction of insects by more than 50 percent and of Lepidoptera (i.e., moths) by about 75 percent, compared to […] high-pressure mercury lamps. This means that proper light selection can minimize risk to moths and other insects while still providing visibility for human needs.”
Even asphalt, glass panels, windows, lawns and roofs worsens light pollution, by reflecting both artificial and sun light. The light becomes polarized on these artificial surfaces. Light reflected from different things can have different polarizations. Polarized light’s electromagnetic field is different from other light. Many insect species can “see” differences in light polarization. For some, it is their prime means of getting about. To animals which use polarized light for navigation, artificial surfaces such as asphalt reflect light which makes them appear as water. Stoneflies will lay their eggs on asphalt, rather than on the surface of water, and the offspring die.
Tinted glass has reflective properties that produces a kind of light pollution of its own. Many birds are killed by it. Window reflections off of glass create seemingly harmless places to fly. Many birds will see sky, a tree, or whatever else is in the vicinity when looking at a window. The reflections off glass paneled buildings can appear to birds as if the buildings were not there. Many species, regardless of the species’ rarity, are affected. Assuming the birds were not suffering other ailments, the effects of light distortion from manmade objects is the cause of these bird-window collisions. According to a webpage posted by the Fatal Light Awareness Program, or F.L.A.P., more than 140 different species of birds have collided with buildings in the city of Toronto, Canada alone. The F.L.A.P website claims night artificial lighting confuses birds, and adds confusion to the already “invisible” buildings. Also, according to www.urbanwildlands.org, each year over four million migrating birds are killed in collisions with lighted communications towers in the United States.
Young seabirds of a threatened Hawaiian species, known as “Newell’s Shearwater”, use moonlight reflected off the surface of the water to guide them during their first flights. Normally, the fledglings use light to fly toward the moon, which happens to be on the horizon, and therefore most importantly, the young birds fly out to the ocean. When city lights are more distracting than the moon, the birds sometimes fly into towns. In a city, a seabird can suffer crashes into buildings, or eventually plunge to its death from exhaustion.
Two other species, the dark-rumped petrel and the band-rumped petrel have similar problems. Correspondingly classified as “endangered” and “rare”, the two species have the same problem on the island of Kauai, Hawaii as the Newell’s Shearwater.

Fish, a marketable commodity, and food for animals including seabirds like the ones I’ve just mentioned, are detrimentally affected by light pollution as well. Squid fishing boats lure their catch with metal halide lamps. According an article published in 2008 in the National Geographic near the continent of South America “a single fishing fleet” is brighter than either of South American cities Buenos Aires (population 13 million) or Rio de Janeiro (population 6 million).
The International Dark-Sky Association says that there are studies which show migrations of fish such as salmon, herring, halibut, and sand lance, are all adversely affected by light pollution. Light pollution can affect the fish in ways such as detaining them in well lit bank/coastal areas. According to the International Dark-Sky Association, Herring fish are more active at night and slow down when under sun-like artificial light. These two examples prevent fish from continuing their natural migration.
Polarized light, from artificial lighting, which I mentioned earlier in relation to insects, shines off litter in oceans and prompts some sea-faring animals to eat the trash. This is usually not healthy for them, and sometimes results in their death(s).

There are more effects of light pollution than directly affecting astronomy and bugs, birds, fish, and all manners of creatures. How is all the wasted artificial light produced? Imagine how much fossil fuel is consumed. The production of light pollution pollutes in other ways as well. Although electricity is generally affordable, the combined cost for light shining into outer space is on the scale of millions of U.S. dollars in the U.S. per year and billions per year worldwide.

There are various claims that deny the benefits of outdoor night lighting. The Dark-Sky Association claims road lighting’s bright glare is distracting for driving. Unshielded highway lights are much brighter than the actual light reflecting off the road(s). The Dark-Sky Association website says unshielded harsh light can damage your night vision. Human night vision is triggered by overall dim surroundings, and large black spaces in our vision. The starkly contrasting street lights interrupt the dark backdrop. The study says that the lights damage our eyes at night. The street lights standing in relief against the darkness bombard damage special cells, commonly called “rods”, which have a higher light sensitivity than the diurnal “cone cells”, with too much light.

Have you seen those smaller, old fashioned style fake lampposts? Fake lampposts usually produce more light than the actual guttering oil lamps they are designed to resemble. Fake lampposts’ white, plastic tops shine light in almost every direction. This light enters the skies above, nearby windows, and places other than the immediate walkway and scenery they’re supposed to light.
Cities in London and Scotland had motivation to prevent light shining into the sky during World War II. Street and automobile lights illuminated buildings. This aided enemy bomber airplane pilots to find their targets more easily. As a solution, covers were installed on street lights, in order to reflect their light downward, and shaded vehicle headlights were implemented.
Today’s automobile headlights produce their own light pollution. Major highways appear as great long steaming blurs in time lapse footage.
Also, crime prevention is not necessarily aided by outdoor lighting. Uncovered lights become much easier to see than anyone actually lurking in the background (see photographs).

There are solutions to light pollution problems. Many of them are very affordable.

Please, turn lights off when they are not benefiting anyone.

Motion sensor porch lights, depending on motion activity, are better than porch lights turned on all the time.

The Dark-Sky Association recommends shields and covers for exterior lighting. These shields and light covers are the industrial looking accessories usually seen in parking lots, and on other commercial property. These shielded lights are reportedly superior to their glaring, unshielded counterparts.

A possibly more moth friendly type of light bulb I mentioned earlier is good for many light pollution reduction issues. The Dark-Sky Association recommends that people should use sodium (especially low pressure sodium) light bulbs over popular mercury vapor bulbs for exterior lighting. Low-pressure sodium lights are usually much more efficient, thus conserving saving electricity as well.
Astronomers have been the main advocates of anti-light pollution measures. However, light pollution is not isolated to simply the sky. Light pollution is wasteful, harmful to the environment, creates health problems, and affects many other aspects of our world.

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