One-Third of Humanity Can't See the Milky Way Anymore

The Milky Way over Mitten Park and the Green River in Dinosaur National Monument, one of the darkest places in the United States. The galaxy we call home is a sight one-third of humanity can no longer see. Image credit: Dan Duriscoe

The view of an ink-black, star-studded night sky is becoming a rarity—something only a small fraction of humanity can hope to experience, according to the most detailed study of light pollution compiled so far. “Light pollution” refers to the stray light from vehicles, homes, and industry—a form of pollution that’s often overlooked, but which has been on the rise ever since the invention of electric lighting. It now hampers the view of the night sky for the majority of people around the world. According to an international team of scientists, more than 80 percent of the world’s population now live under light-polluted skies. A smaller fraction—about one-third—live under skies that are murky enough to blot out the Milky Way. A summary of their findings was published today in the journal Science Advances.

Although long decried by both professional and amateur astronomers, the effects of unchecked light pollution also threaten to affect our lives and our environment in ways that impact more than just astronomy, according to the project’s lead scientist.

“Life on earth evolved over millions of years, and normally, it’s been light for half the time, during the day, and dark for half the time, at night,” lead author Fabio Falchi, of the Light Pollution Science and Technology Institute in Italy, tells mental_floss. “But in the last few decades, things have changed. Now, over large parts of our planet, we have light all day and also all night.”

Europe, Africa, the Middle East, and India in New World Atlas of Artificial Sky Brightness, as seen in Google Earth. Image credit: Falchi et al. in Science Advances

The extra light can have adverse health effects on humans and other animals, Falchi says, by affecting the production of melatonin, a hormone that helps regulate the circadian rhythms that control the sleep-wake cycle.

Falchi and his colleagues have released an updated and expanded edition of a light pollution atlas they first published more than a decade ago. The New World Atlas of Artificial Sky Brightness was compiled by correlating data from NASA’s Suomi NPP satellite (National Polar-orbiting Partnership) together with some 30,000 ground-based light-level measurements. The result is the most accurate assessment yet of the worldwide effects of light pollution. 

While other kinds of pollution, such as air and water pollution, often take the heaviest tolls in the developing world, light pollution is most pronounced in well-off regions, such as the United States, Europe, and parts of Asia. Some 99 percent of Americans and Europeans live under light polluted skies, the study found. In contrast, in the African nations of Chad, the Central African Republic, and Madagascar, some three-quarters of residents still live under dark skies. In the developed world, some of the darkest skies are found in Canada and Australia. 

Light pollution over Joshua Tree National Park. And yet—as the National Park Service says—the park has some of the darkest skies in southern California. Image credit: Dan Duriscoe

The good news, says Falchi, is that fairly simple measures can be taken to mitigate light pollution. For example, street lights can be equipped with shields that minimize the amount of light that escapes upward. And modern LED lighting can be dimmed more easily than older kinds of lights, allowing them to shine at reduced brightness levels when that’s all that’s needed.

Alan Dyer, a Canadian photographer known for his stunning portraits of the night sky, compares a dark sky to an endangered species of animal—a rare treat which, for some people, is worth traveling a great distance to see. “When you lose contact with the night sky, you really lose contact with your place in the universe,” Dyer tells mental_floss. “There’s nothing in nature that inspires more curiosity, wonder, and awe than looking up at the stars, and particularly the Milky Way.” Based in rural Alberta, Dyer has easier access to dark skies than most North Americans, but over the last 25 years, he’s seen the lights of Calgary, as well as smaller towns, steadily getting brighter.

For Falchi, who lives near Milan in northern Italy, a dark night sky is virtually impossible to find. “A really good night sky is no longer available in Italy,” he says. “I can drive two hours to a fairly good mountain site, but even there, there’s some light pollution.” A few more hours gets him close to the Austrian border, which is darker still, but even there, he notes, the sky is only really dark directly overhead. When he looks southward, toward Italy’s industrial region, an orange glow looms above the horizon. 

Mark Ralston, AFP/Getty Images
How a Hairdresser Found a Way to Fight Oil Spills With Hair Clippings
Mark Ralston, AFP/Getty Images
Mark Ralston, AFP/Getty Images

The Exxon Valdez oil tanker made global news in 1989 when it dumped millions of gallons of crude oil into the waters off Alaska's coast. As experts were figuring out the best ways to handle the ecological disaster, a hairdresser from Alabama named Phil McCroy was tinkering with ideas of his own. His solution, a stocking stuffed with hair clippings, was an early version of a clean-up method that's used at real oil spill sites today, according to Vox.

Hair booms are sock-like tubes stuffed with recycled hair, fur, and wool clippings. Hair naturally soaks up oil; most of the time it's sebum, an oil secreted from our sebaceous glands, but it will attract crude oil as well. When hair booms are dragged through waters slicked with oil, they sop up all of that pollution in a way that's gentle on the environment.

The same properties that make hair a great clean-up tool at spills are also what make animals vulnerable. Marine life that depends on clean fur to stay warm can die if their coats are stained with oil that's hard to wash off. Footage of an otter covered in oil was actually what inspired Phil McCroy to come up with his hair-based invention.

Check out the full story from Vox in the video below.

[h/t Vox]

This Self-Cloning Tick is Terrorizing More States

Few arachnids are as demonized in the summer months as ticks, the parasitic little nuisances that can spread disease in humans and pets. That's not likely to change now that there's a exotic new species that can not only self-replicate, but is also poised to attack animals like a colony of swarming fire ants.

This super-tick is Haemaphysalis longicornis, or the longhorned tick, native to East Asia and imported to the U.S. by unknown means. The first North American sighting took place in August 2017 in New Jersey when a farmer walked into a county health office covered in nearly 1000 ticks after shearing a pet sheep that had been infested. The insect was then spotted in Virginia, West Virginia, and Arkansas, with caution advised in Maryland. As of this week, it’s now a confirmed resident of North Carolina, The Charlotte Observer reports.

H. longicornis invites more dread than a conventional tick for several reasons. It can “clone” itself, with females laying up to 2000 genetically identical eggs without any assistance from a male, a process called parthenogenesis. Reproduction is faster, with offspring appearing in just six months compared to two years for common deer ticks. It’s also an aggressive biter, nibbling on any animal flesh it can latch on to, and is able to transfer a host of diseases in the process—some of them fatal. In addition to Lyme, longhorned ticks can transmit the flu-like ehrlichiosis bacteria and the rare Powassan virus, which can cause brain inflammation.

The news isn’t much better for livestock. Given enough opportunity, the ticks can siphon enough blood from an animal to kill it, a process known as exsanguination. The attack can become so concentrated that pets have been spotted with ticks hanging from them like bunches of grapes.

New Jersey officials have confirmed the tick has survived the winter by burrowing underground, a somewhat ominous sign that the invasive species might be durable enough to become a widespread problem. Experts recommend taking all the regular precautions, including wearing long pants when outdoors, using repellent, and examining yourself and your pets for ticks. While the longhorned tick hadn’t yet displayed a taste for human flesh, it’s better to be safe than sorry. As for the sheep: following a chemical treatment, she made a full recovery.

[h/t Charlotte Observer]


More from mental floss studios