Sommaire pour June 2017 de Discover

Solitude. It’s an apt word for exactly one of our planet’s continents, and it’s a necessary state of being if we really want to let our minds wander. In this issue, solitude is key in two very different stories. We head south to Antarctica, flying low in a retrofitted DC-8 jet, measuring the toll of global warming (on page 36). Then we dive into daydreaming, where our unconscious minds get to work (on page 30). The Antarctica we think we know from a distance is one of stark isolation and desolation, an endless expanse of ice. But that rock-solid foundation is slipping away, and fast. The melting in some areas cannot be stopped. One crew of NASA pilots and scientists has watched it disappear. Discover Associate Editor Eric Betz traveled…

“CANCER HAS BEEN CURED a thousand times.” So says Christopher Austin, the director of the National Center for Advancing Translational Sciences (NCATS) at the National Institutes of Health. The catch? All those cures happened in mice. Hundreds of drugs have wiped out mouse tumors, only to fail in human trials. Or worse, they turned out to be toxic to humans. An astounding 90 percent of all drug trials never make it to FDA approval. The humble lab mouse shoulders much of the blame. But should scientists ditch their furry model altogether, or can they simply build a better mouse? Mice entered the lab back in the early 1900s. Geneticist Clarence Cook Little suspected cancer was an inherited disease, and mice — shortlived and low maintenance — were the ideal test…

U.S. Wildfires Humans vs. Lightning* 84% of wildfires in continental U.S. are ignited by humans Total area burned by human-caused fires: LENGTH OF FIRE SEASON 154 days Human-ignited fires 46 days Lightning fires SEASONALITY OF FIRE SPRING 38% SUMMER 24% FALL 19% WINTER 19% SPRING 9% SUMMER 78% FALL 12% WINTER 1% MOST COMMON DAY FOR FIRES JULY 4th Human JUNE 22nd Lightning * Figures based on fires documented from 1992-2012 that were extinguished or managed by government agencies. Source: “Human-started wildfires expand the fire niche across the United States,” PNAS, 2017 “Per pound, this is the most incredible fossil I have ever seen. It is just packed with stuff! — University of Alberta paleontologist Scott Persons, on the discovery of a partial, feathered dinosaur tail embedded in amber alongside insects.” Degrees of Separation…

EVERYONE SMILES IN THE SAME LANGUAGE, RIGHT? For decades, psychologists have backed up the idea that facial expressions are universal. Paul Ekman’s research in the 1960s was a driving force behind this popular notion. He found cultures worldwide describe facial expressions the same way: For example, a scrunched-up nose signals disgust. Even in the isolated Fore tribe of Papua New Guinea, Ekman’s theory held up. But other researchers believe subtle differences in facial expressions exist between cultures. In Science Smackdown, we let experts argue both sides of the question. The Claim DIFFERENT PLACES, DIFFERENT FACES “The Ekman theory, that certain facial configurations signal specific emotions universally, just doesn’t hold up,” says James Russell, a psychologist at Boston College. In a recent paper in the Proceedings of the National Academy of…

It seemed a strange realization. How, after AA meetings failed to help me overcome my cravings, could seeing a film about a quest to destroy an evil ring do the trick? With popcorn and soda in hand, my friends and I settled into our seats. The lights dimmed. Ghostly music filled the room, and Cate Blanchett’s narration surrounded us: “The world is changed. I feel it in the water. I feel it in the earth. I smell it in the air. Much that once was is lost. For none now live who remember it.” I let out a sigh of relief. I was seven months sober from alcohol and crack cocaine, still struggling to remain abstinent. Despite going to Alcoholics Anonymous meetings, the cravings were overpowering, compounded by emotional turmoil…

At its core, Earth’s climate system is actually quite simple. Sunlight is most intense in the tropics along the planet’s equator. And physics is constantly trying to push heat from the tropics toward the poles, where it can radiate back to space. “All the atmospheric circulations that occur, and all the ocean circulations that occur, are basically doing that — they’re transporting heat,” says veteran climatologist Gerald Meehl of the National Center for Atmospheric Research. For example, the Gulf Stream moves heat into the North Atlantic, bringing Europe a pleasant climate, and then it radiates the heat out into space. The poles also have their own currents. Antarctica’s strong Circumpolar Deep Current circles the entire continent, driven by strong winds called westerlies, which also create the Southern Ocean’s dangerous and…

In her 53 years, many spent bucking a system that impeded her pursuit of mathematics, Noether had an extraordinary impact on both algebra and physics. There’s no telling what else she might have accomplished if society and fate had been more kind. In 1915, two of the world’s top mathematicians, David Hilbert and Felix Klein, invited Emmy Noether to the University of Göttingen to investigate a puzzle. A problem had cropped up in Albert Einstein’s new theory of gravity, general relativity, which had been unveiled earlier in the year. It seemed that the theory did not adhere to a wellestablished physical principle known as conservation of energy, which states that energy can change forms but can never be destroyed. Total energy is supposed to remain constant. Noether, a young mathematician…

We are at our cutest as infants. We’re most helpless then, too. But every infant has a help button: Cry, and most likely any adult within earshot will rush over to hold and soothe them with a gentle song. Other primate species, including chimpanzees and macaques, also cradle and carry their fussy young. But human caregivers do something extra. “We added the singing,” says psychologist Sandra Trehub, professor emeritus at University of Toronto Mississauga. No one knows when parents first sang to infants, but the practice is ancient and universal. “There seems to be evidence of singing to infants throughout recorded history,” says Trehub, who has studied musicality in infants and children for decades. All human cultures perform songs specifically for babies — so-called “infant-directed songs.” Simpler, slower and repetitive,…

BRENT SEALES has made a career of unlocking lost secrets. With specialized software he and his team developed, the University of Kentucky computer scientist can read ancient scrolls too fragile to unroll. Recently, he watched as Hebrew consonants from the charred remains of an ancient Jewish scroll flashed across a computer screen. Archaeologists discovered the scroll in 1970 at En-Gedi, the site of an ancient synagogue in Israel that burned in the sixth century. The fire reduced the document to a charred lump that crumbled at the slightest touch. But last year, Seales’ software virtually unwrapped a three-dimensional scan of the scroll’s internal structure, flattening the text to two-dimensional images. Centuries after it was last read, the scroll’s writing was once again accessible. Inside were two chapters of the Book…

“IN 18 YEARS PRECISELY, the planets will align ever so nicely.” This catchy rhyme from Disney’s Hercules was part of a prophecy meant for Hades, god of the underworld. But it’s also pretty darn close to this word’s most common scientific definition: when one astronomical object aligns with another. (The term, pronounced SIZ-uh-jee, also pops up in biology, math and psychology.) A familiar example of this phenomenon is an eclipse. In fact, every eclipse is a syzygy, but not all syzygies are eclipses — just like the prophetic example above, the term could be applied in situations where only planets are in alignment.…

As the atmosphere warms, heat is transferred to the oceans, which causes water expansion and rising sea levels. Today, Earth’s oceans are warmer than they have been in 100,000 years, according to research published in Science in January. Scientists discovered this by using sediment cores from around the world to reconstruct sea surface temperatures from the last interglacial period, which started roughly 129,000 years ago. At that time, temperatures were similar to those from before the Industrial Revolution. The study also showed that 4,000 years later — so, 125,000 years ago — sea surface temperatures had warmed up to nearly match today’s readings. That means that, during the interglacial period, it took the planet millennia for a temperature increase that humans managed in just centuries. Alarmingly, sea levels back then…

Earth isn’t the only place with blustery days. Mars also experiences gale-force winds that blow up to 60 mph, forming sand dunes that resemble those on our home planet. This photo, by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter, shows a field spanning 1 kilometer of wind-carved ripples in the Red Planet’s northern mid-latitudes. To reveal greater detail, the image was rendered in blue. Researchers compared this photograph with images taken four years earlier at the same site, one of more than 60 NASA is studying. The images will help scientists understand how wind changes the terrain over time.…

HEARING HAIRS RESTORED Tiny hairs in our inner ears, called cochlear hair cells, are vital to our natural perception of sound, and once we lose them, we don’t grow them back. But scientists published in Cell Reports that they’ve discovered a way to regenerate those cells in mouse, primate and human tissue samples. After exposing supporting cells — cells that can create new cochlear hairs — to a specialized drug mixture, the team saw significant new hair cell growth. BABY BUMP Birds don’t give birth to live young, but their distant ancestors did. Archosauromorphs, which existed about 250 million years ago, were the creatures that evolved into crocodiles, dinosaurs, birds and pterosaurs. Experts thought these beasts laid eggs, much like their modern descendants. But a new Nature Communications paper details…

The narrow and mountainous Antarctic Peninsula extends north from West Antarctica some 800 miles toward Chile. This picturesque region has warmed at least twice as fast as Earth’s overall average. That’s led to the collapse of ice shelves. Larsen A, at the peninsula’s northern tip, crumbled in 1995. By 2002, its neighbor Larsen B collapsed. Both ice shelves were thousands of years old. Since then, scientists have kept a close watch on Larsen C. It’s the biggest ice shelf on the peninsula and the continent’s fourth largest. A 70-mile-long crack is currently causing Larsen C to calve a Delaware-sized iceberg into the Southern Ocean. The mammoth iceberg — roughly 10 percent of the entire ice shelf — now dangles like a broken tree limb, tethered by just 12 miles of…

The oldest object known to humans fell from the sky on Feb. 8, 1969, with the furor of a divine omen. The blue-white fireball streaked over northern Mexico at 1:05 a.m., ending with a staccato of booms heard from hundreds of miles away. A small asteroid had struck Earth’s atmosphere and exploded — raining thousands of fragments over the desert. NASA dispatched scientists to the site, and days later they returned with 13 fragments of the space rock. Each was coated with a smooth, glassy rind, the heat of atmospheric entry having melted the exterior. But when the rocks were cracked open, their insides looked pristine: gray-black stone jumbled with numerous white and gray nuggets the size of peas. The Allende meteorite, named for the Mexican village near the landing…

1 Is a swamp any swampier than, say, a marsh or mire? It depends. Some dictionaries and government agencies define swamps as forested. 2 Other institutions get less bogged down in the details and consider any soggy spot a swamp. The preferred general term by researchers, however, whether talking swamp, marsh or mire, is wetlands. 3 Wetlands, generally speaking, are any land where the water table is at or near the surface and the level of water saturation determines the flora and fauna that live there, as well as the substrate, or soil. 4 Most plants and animals not specifically adapted to live in wetlands don’t. The omnipresent water makes it too difficult for outsiders to thrive there. 5 Species native to wetland ecosystems can be rather enterprising. Many carnivorous…