Do you remember when did you see a sky full of stars last? It’s been many years for me, I even can’t remember when I saw last. A lot of young people didn’t see even once, because of the light pollution in cities, since they were born in cities and probably never went to the countryside.
Graphic: Light pollution in cities
Normally, a healthy person with normal/clear vision can see between 2,500-4,000 stars with the naked eye – in a clear and moonless night and far from the light-polluted areas (see: How many stars one can see with the naked eye?)
But, according to a new global atlas of light pollution produced by Italian and American scientists, the Milky Way cannot be seen at night by one-third of humans. We’re missing the greatest show in the Universe – the Universe itself.
The graphic below shows how the Earth’s sky is seen from inside inner-city, suburban areas, rural areas, and the countryside far away from cities and towns. What most of the people missing is incredible.
What is Light Pollution?
Light pollution is the artificial light that is not being efficiently or completely utilized and is often pointed outwards or upwards and not downwards. A major side-effect of urbanization, it spoils the night environment.
Losing the Dark
A video by the International Dark-Sky Association – “Losing the Dark”.
Starry skies are a vanishing treasure because light pollution is washing away our view of the cosmos. It not only threatens astronomy, but it also disrupts wildlife and affects human health. The yellow glows over cities and towns – seen so clearly from space – are a testament to the billions spent in wasted energy from lighting up the sky.
To help raise public awareness of some of the issues pertaining to light pollution, Loch Ness Productions in collaboration with the International Dark-Sky Association has created a 6.5-minute “public service announcement” called Losing the Dark. It introduces and illustrates some of the issues regarding light pollution, and suggests three simple actions people can take to help mitigate it.
Losing the Dark is a joint production of the International Dark-Sky Association and Loch Ness Productions.
More information and links to downloads at the darksky.org
Transcript of the “Losing the Dark” video:
We live on the surface of a planet spinning on its axis once every 24 hours. Its rhythms of day and night are embedded in the biological makeup of all life.
During the day, we bathe in the glow of the Sun.
As night approaches, darkness takes over. It’s a time to rest, to rejuvenate, to marvel at the beauty of the night.
Until just over a century ago, our night skies were very dark. Now, even the wilderness is invaded by light.
Our cities glow at night. Buildings are lit up. Unshielded lights blind us as we travel along our streets and roads. All these artificial lights overpower the darkness.
The waste of energy is obvious, even from space.
Much of that yellow glare the astronauts see comes from street lights. They produce most of the light pollution on the planet. The glare is scattered by the atmosphere, creating sky glows over the landscape. We are losing the dark of night at the speed of light.
Light pollution threatens the health of every living thing on Earth. Lights at night disrupt plant growth. Unshielded lights contribute to the deaths of countless land and sea animals each year.
Migrating birds crash into illuminated buildings. Newly hatched sea turtles mistake the glow of electric lights for the shimmer of the ocean surface.
Bright lights at night also directly affect humans. Drivers and pedestrians temporarily blinded by poorly designed lights have suffered tragic accidents. Light pollution poses a silent threat to our health. Exposure to light at night disrupts the circadian rhythms that regulate our sleep cycles. People working at night under bright lights or living in light-polluted cities face a higher risk of developing diseases such as breast and prostate cancer.
Astronomers know all too well the problems caused by lighting up the night. They need clear, dark skies to study the many fascinating objects in the universe. Light pollution simply washes out their view of the cosmos.
Lighting up the night sky wastes money and fossil fuels. To keep a 100-watt light bulb turned on every night for a year takes the equivalent energy output from burning half a ton of coal. Multiplied by the billions of lights blazing up from Earth, the cost of energy we use to light up the night is colossal.
While lighting is needed, there are some simple things we can do to ensure that it’s neighborhood-friendly, energy-efficient and helps preserve dark skies. We can replace light fixtures that send light up to the sky with ones that direct light down, exactly where we want it. They’re called “fully shielded fixtures”.
We can also illuminate only the places that need it. And, of course, we can just turn off unnecessary lights.
These are smart ways to use lighting. They offer simple solutions to problems caused by light pollution. We have a choice – between wasting resources by sending light to the sky – or learning to use light more responsibly.
Light pollution is a problem each of us can help solve. Together, we can bring back the dark of night to planet Earth.
When our prehistoric ancestors studied the sky after sunset, they observed that some of the stars were not fixed with respect to the constant pattern of the constellations. Instead, five of them moved, slowly forward across the sky, then backward for a few months, then forward again, as if they couldn’t quite make up their minds. We call them planets, the Greek word for “wanderers.” These planets presented a profound mystery. The earliest explanation was that they were living beings. How else to explain their strange looping behavior. Later they were thought to be gods, and then disembodied astrological influences. But the real solution to this mystery is that the planets are worlds, that the Earth is one of them, and that they all go around the sun according to precise mathematical laws. This discovery has led directly to our modern global civilization.Carl Sagan, Cosmos: A Personal Voyage, Ep. 03 “Harmony of the Worlds”
Light pollution is also bad for health and the environment
In the article titled “The marvel of LED lighting is now a global blight to health “, Richard G ‘Bugs’ Stevens, professor of community medicine and health care in the School of Medicine at the University of Connecticut says:
“Light pollution is often characterized as a soft issue in environmentalism. This perception needs to change. The inappropriate or excessive use of artificial light – known as light pollution – can have serious environmental consequences for humans, wildlife, and our climate. Even relatively small amounts of light can be noticed and create problems.”
- Light pollution wastes a lot of energy and money. Producing energy is expensive and usually harms the environment. Wasting it causes huge damage to wildlife.
- Artificial lights disrupt the world’s ecosystems. It’s especially bad for nocturnal animals. Scientific evidence suggests that artificial light at night has negative and deadly effects on many life forms including amphibians, birds, mammals, insects, and plants. Read more: “Light Pollution Effects on Wildlife and Ecosystems” on DarkSky.org
- Many insects are drawn to light, but artificial lights can create a fatal attraction (remember the insects flying around an artificial light like crazy). Declining insect populations negatively impact all species that rely on insects for food or pollination.
- Light pollution affects the circadian rhythm of humans (a sleep-wake pattern governed by the day-night cycle, our biological clock)
- Research suggests that artificial light at night can negatively affect human health, increasing risks for obesity, depression, sleep disorders, diabetes, breast cancer and more.
- There is even no clear scientific evidence that increased outdoor lighting deters crimes. A 2015 study published in the Journal of Epidemiology and Community Health found that streetlights don’t prevent accidents or crime, but do cost a lot of money.
What can be done?
- Installing quality outdoor lighting could cut energy use by at least 60-70 percent, save billions of dollars worldwide and cut carbon emissions dramatically.
- Outdoor lighting should be fully shielded and direct light down where it is needed, not into the sky.
- Fully shielded fixtures can provide the same level of illumination on the ground as unshielded ones, but with less energy and cost.
- Unnecessary indoor lighting – particularly in empty office buildings at night – should be turned off.
- New lighting technologies can help conserve energy. LEDs and compact fluorescents (CFLs) can help reduce energy use and protect the environment, but only warm-white bulbs should be used.
- Dimmers, motion sensors, and timers can help to reduce average illumination levels and save even more energy.
The real, destructive consequences of light pollution are seldom recognized, but it is a problem with easy solutions that make economic sense. All life forms rely on the Earth’s regular rhythm of day and night to regulate internal cycles. Many animals and insects use the protection of darkness to safely forage and mate.
We exist in a balance with our environment, a delicate balance that we are shifting. In the process, we are also losing our connection to the night sky, the Milky Way, and the Universe beyond.
- “Light Pollution Hurts the Night Sky for Astronomy” on cescos.fau.edu
- “Why Living In Cities Sucks” on Gizmodo
- “Light Pollution” on the International Dark-Sky Association website (darksky.org) – The International Dark-Sky Association works to protect the night skies for present and future generations.
- The New World Atlas of Artificial Sky Brightness on cires.colorado.edu
- “The Problems of Light Pollution” on cescos.fau.edu