Sommaire pour May 2013 de Discover

Evolution Motivation In “Evolution Full Tilt” (page 32), Steven Kotler wrote of Homo evolutus, a stage when humans would control their own evolution. Thought-provoking article. Evolution has an overarching goal: natural selection. What will be the overarching goal of human-driven evolution? Beauty? Desire? Self-actualization? Living forever? Power? These are selfish goals that deny the evolution process that got us here, and it is reasonable to suspect that Homo evolutus as a species will be more vulnerable, thus less capable of survival over the long term than what came before. St. Louis, MO In “Evolution Full Tilt,” you quote Andrew Hessel saying, “When I was a child, Down syndrome was a real problem. Today roughly 90 percent of all fetuses with Down syndrome are terminated.” Mr. Hessel’s implication is clear: problem…

At the International Space Station, Robonaut 2 holds an air velocity meter in the densely packed Destiny laboratory in March 2012. The robot will be “another pair of hands” for the space station crew, said NASA project leader Ron Diftler in a video produced by the Johnson Space Center earlier this year. Built in collaboration with General Motors, the robot was designed with human-shaped hands and arms, allowing it to use the same tools and controls as the astronauts. NASA’s goal is to test and train the robot to autonomously perform tasks that are too routine or dangerous for the crew, including those outside the station’s airlocks.…

Good news for fans of planet Earth: The seasonal hole in the ozone layer over Antarctica was at its second-smallest point in the past 20 years, according to new research from NASA and the National Oceanic and Atmospheric Administration (NOAA). Could this be the first real sign that the ozone layer is recovering after decades of destruction? The ozone layer, which includes oxygen and nitrogen as well as ozone, forms a protective belt in the stratosphere about 10 to 18 miles above the Earth, reflecting the sun’s harmful ultraviolet radiation. In the 1960s and ’70s, the widespread release of chlorofluorocarbons (CFCs), chemicals used primarily in spray aerosols, led to a partial breakdown of the layer. Since the 1980s, the ozone layer above Antarctica has been especially affected because the region’s…

Increased verbal aggression Fq < 1 The shorter your index finger, the sharper your tongue: In both men and women, a lower Fq can predict more verbal sparring. Improved athletic ability Fq < 1 A greater surge of prenatal testosterone can be an indicator of high levels of achievement in sports, as well as a mental toughness in athletics. In one study, college varsity athletes (male and female) were found to have shorter index fingers than other students. Improved sense of direction Fq < 1 In women, a more masculine digit ratio tends to predict a better sense of direction, backing up past research that found men tend to have better spatial cognition than women. More physical aggression Fq < 1 Men with shorter index fingers are more likely to…

STAR TREK INTO DARKNESS After the wild success of 2009’s franchise reboot, stakes are high for Kirk and crew as they fight both an intergalactic terrorist and the dreaded Sophomore Slump. Director J.J. Abrams won’t confirm rumors this outing is a retelling of The Wrath of Khan, but with the reliably intense Benedict Cumberbatch (BBC’s Sherlock, The Hobbit) on board as the villain, does it really matter? (Chris Pine, Zachary Quinto; Paramount, May 17) IRON MAN 3 The billionaire with the bespoke, bullet-stopping suit faces down a lord of the rings: the Mandarin, a descendant of Genghis Khan who gets his superpowers through finger jewelry he nicked from a crash-landed alien ship. (Robert Downey Jr., Gwyneth Paltrow, Ben Kingsley; Disney, May 3) AFTER EARTH For many teenage boys, a road…

The King of Random, aka Grant Thompson, is this year’s winner of the Citizen Science contest sponsored by DISCOVER and Instructables. Thompson’s nine-minute video details step-by-step construction of an oxyhydrogen generator, using electricity from a car battery to convert water into hydrogen. “With a simple technique, we can turn one of the most abundant materials on Earth into a highly explosive gas,” Thompson says in the video. “Some people say that this is the fuel of the future.” Check out the rest of the entries at instructables.com/contest/citizensci2012/…

AT THE BASE OF A BRUSH-COVERED hill in South Africa’s Northern Cape province, a massive stone outcropping marks the entrance to one of humanity’s oldest known dwelling places. Humans and our apelike ancestors have lived in Wonderwerk Cave for 2 million years — most recently in the early 1900s, when a farm couple and their 14 children called it home. Wonderwerk holds another distinction as well: The cave contains the earliest solid evidence that our ancient human forebears (probably Homo erectus) were using fire. Like many archaeological discoveries, this one was accidental. Researchers weren’t looking for signs of prehistoric fire; they were trying to determine the age of sediments in a section of the cave where other researchers had found primitive stone tools. In the process, the team unearthed what…

Astronomer Brian Schmidt vividly recalls his first inkling of the astonishing discovery that would win him a share of the 2011 Nobel Prize in Physics. It was a moment back in 1997 filled not with euphoria, but trepidation. Based at the Australian National University in Canberra, Schmidt was attempting to pinpoint the positions of supernovae — exploding stars that, at their apex, can outshine 5 billion suns. These bright, celestial objects serve as beacons across the sky, helping astronomers peer deep into space and calculate the size, shape and mass of the universe. Since most of Schmidt’s colleagues were scattered across the globe — in Europe, South America and the United States — the group had developed a 24-hour relay approach to analyzing their telescope data: Schmidt would work all…

Euclid Equipment: A visible-wavelength camera and near-infrared camera/spectrometer. Expected Launch: By 2020 Mission: Piece together the past 10 billion years of cosmic history to determine how dark energy has sped up the expansion of the universe. Method: Euclid will measure gravitational lensing, where light from far-off objects bends around a massive body (a regular star or cluster of dark matter), to determine dark matter’s distribution. The observatory will also measure patterns in the distribution of galaxies left by acoustic waves in the early universe. Because these patterns have a fixed size, they can be used to determine the distance of objects and probe the expansion of the universe for the effects of dark energy. Wide-Field Infrared Survey Telescope (WFIRST) Equipment: Infrared telescope with a field of view nearly twice the…

An ant faced with two paths to a food source may not know which is best, but an ant colony can quickly sort this out: Individuals leave trails of chemicals called pheromones to mark the route from nest to food and back. As other ants follow, pheromones build up more rapidly along the shortest route, reinforcing the scent and guiding the colony en masse. A honeybee colony similarly pools its resources to select a home. Several hundred “scouts” head out to search, reporting back on potential sites. Other scouts follow up, choosing sides until a quorum has settled on a particular spot. This life-or-death decision draws on the collective wisdom — or swarm intelligence — of the hive. Inspired by examples like this, engineers are producing ensembles of small, insect-like…

THERE IS SOMETHING SPECIAL about touch. It is the truth teller that proves the other senses: A bench bearing a “wet paint” sign is not truly wet until we have tapped it with a probing finger. Conversely, an air of unreality hangs over anything we cannot touch. A scientist studying the geology of distant planets and long-ago times, then, seems condemned to live in a perpetual bubble of abstraction. A conversation with Carl Agee quickly sets me straight. His title is director of the Institute of Meteoritics at the University of New Mexico, but he might be better described as a man who touches the untouchable. Agee daily re-creates conditions deep inside Earth, explores geologic events from billions of years ago and probes the chemical secrets of other planets. Recently,…

WHEN IT COMES TO QUESTIONS, I HAVE A BIT OF A PARADOX on my hands. See, it’s a basic rule of editing and writing, something drilled into me since my earliest days in this field: Tell a complete story. Leave no questions in the reader’s mind. Unanswered questions = unsatisfied readers. The thing is, that rule doesn’t really apply where DISCOVER is concerned. As you read through this issue, I think you’ll come away with plenty of questions. In fact, I hope you do. I know I did after I read “Trait vs. Fate” (page 48), our feature on behavioral epigenetics, which explores whether traumatic experiences in our past, or in our ancestors’ past, leave molecular residue adhering to our DNA, impacting our own psychological and behavioral tendencies. I found…

MYALGIC ENCEPHALOMYELITIS, or chronic fatigue syndrome, is a perplexing disorder that may seem more like a voodoo hex than an illness. Patients might lie bedridden in dark rooms, in chronic pain, often with multiple neurological symptoms like muscle pain, sweating and dizziness. Doctors have targeted various causes, from herpes viruses to retroviruses to depression. But a surprising new explanation suggests that the disorder is an autoimmune disease of the nervous system caused by overactive B-cells, which are normally responsible for churning out pathogen-killing antibodies. In 2011, two Norwegian oncologists, Oystein Fluge and Olav Mella of Haukeland University Hospital in Bergen, along with colleagues, studied 30 people diagnosed with chronic fatigue immune dysfunction syndrome (CFIDS). Each received either a placebo or a highly specialized chemotherapy drug called rituximab, which rapidly and…

The world has no shortage of great leapers, from hopping kangaroos to high-jumping basketball stars. But according to physicist Daniel Goldman of Georgia Tech, the seemingly simple act of bouncing remains a rich source of research questions. In hopes of designing hopping robots, Goldman and his colleagues first set out to study the physics of bouncing, and in the process they stumbled upon the secret to more effective jumps. To start, mechanical engineering grad student Jeffrey Aguilar built a simple hopping robot. The device consists of an 8-inch-tall rod with a spring at its base. A motor, which is connected to a computer, moves vertically along the rod. When it travels up, the rod shifts down, compressing the spring. This causes the spring to recoil, thrusting it up off a…

Every summer, a pitched battle of wills unfolds within the acorns and hollowed-out twigs of the Northeastern United States. A dark, bulbous-headed ant called Protomognathus americanus invades these tiny abodes and plucks the pearly brood of ants in the genus Temnothorax. The pilfered offspring return with the raiders to their nests, then hatch and grow up to become live-in slaves, tasked with the feeding and care of their slothful masters and their masters’ brood. Because the lives of these ant slaves are so hopeless — they have no chance to reproduce, after all — scientists long assumed they would find no benefit in rebellion. “They are an evolutionary dead end,” explains biologist Tobias Pamminger of the Johannes Gutenberg University of Mainz in Germany. Which is why Pamminger and his colleagues…

Robert Downey Jr.’s slick take on Tony Stark, introduced to the silver screen in 2008, returns in this month’s Iron Man 3. But don’t think that the original Iron Man, who turns 50 this year, is showing any signs of rust. The Marvel superhero, first seen in a March 1963 issue of Tales of Suspense, is busier than ever with his own eponymous comic-book series. He’s also taking an extended leave from the Avengers to join Guardians of the Galaxy, an intergalactic superhero team. Axel Alonso, Marvel editor in chief, tells DISCOVER Associate Editor Gemma Tarlach that Iron Man has no plans for early retirement. Why does Iron Man remain so popular, 50 years after his debut? Iron Man is unique. If there’s a more flawed superhero, I’ve yet to…

Fun in the Sum: MoMath, New York Doodles. Trees. Roller coasters. Music. What do they have in common? Math, of course. The Museum of Mathematics, nicknamed MoMath, celebrates the math found in everyday objects and activities as well as more abstract theories. Since opening in December, MoMath has continued to add to more than 30 hands-on exhibits, offering different levels of interaction based on age and degree of understanding. Visitors can ride square-wheeled tricycles, create fractals using feedback, use a calculator made of string and paint in water, converting even the worst mathphobe into a number lover. momath.org…

NEUROSURGEONS LIVE FOR THE “great saves.” Our specialty is accustomed to more than its share of depressing outcomes, from lives cut short by brain tumors to minds devastated by head injury. Any neurosurgeon relishes the opportunity for a great save — a total cure or a dramatic neurological reversal. The elation of such a moment helps inoculate the surgical psyche against gloomier endings. So when Christine, a quiet woman in her 50s, walked into my office, I was pleased to recognize — after speaking with her for only five minutes — that I had a chance to relieve her of an agonizing affliction. She would be my next great save. Christine had a relatively rare disorder called trigeminal neuralgia, and she had a severe case of it. This disorder, also…

Every story has an ending, but the last act of the universe has yet to be revealed. Its outcome depends on the massive tug-of-war between two monster forces: expansion, which pushes matter outward, and gravity, which pulls it back in. Cosmologists say the winner — and the fate of the cosmos itself — could be determined by another unknown: the behavior of dark energy, which makes up most of the universe. ENDING #1: Big Crunch Expansion proceeds until dark energy reverses itself, working along with gravity to pull matter back together and causing the visible universe to collapse into a single, tiny point, in a reversal of the Big Bang. ENDING #2: Big Rip Dark energy increases over time, eventually becoming strong enough to overcome all other forces and tear…

DARWIN AND FREUD WALK INTO A BAR. Two alcoholic mice — a mother and her son — sit on two bar stools, lapping gin from two thimbles. The mother mouse looks up and says, “Hey, geniuses, tell me how my son got into this sorry state.” “Bad inheritance,” says Darwin. “Bad mothering,” says Freud. For over a hundred years, those two views — nature or nurture, biology or psychology — offered opposing explanations for how behaviors develop and persist, not only within a single individual but across generations. And then, in 1992, two young scientists following in Freud’s and Darwin’s footsteps actually did walk into a bar. And by the time they walked out, a few beers later, they had begun to forge a revolutionary new synthesis of how life…

The wing of a butterfly, the web of a spider, the knee of a flea — no, it’s not a medieval recipe for witch’s brew. It’s a short list of the growing number of insect attributes attracting notice for their core utility and ingenious design. From rendering crystal clear images on screens no matter what the lighting to finding water in the desert, bug-inspired innovation is taking flight. GEMMA TARLACH The Butterfly’s Crystalline Color The brilliant colors on the wings of many butterflies and some bird feathers, such as peacocks, are not, in fact, due to any actual pigment in the wing material itself. Instead, color is created through the prism-like, crystalline structure of the surface. (See interview with Richard Prum, page 32.) The light is split into its various…

MAY SKY CLO K OF THE GODS WITH ITS JEWEL-LIKE RINGS AND GOLDEN HUE, Saturn is the most beautiful of the planets — perhaps the most iconic object in all of science. Now is the ideal time to see the ringed planet, as it rises just before sunset and stays visible all night. A view through even a modest telescope elicits gasps of disbelief: Yes, it really looks like that. It is easy to find — just look to the southeast a few hours after twilight. Saturn hovers about one-third of the way from blue-white Spica (the brightest star in Virgo) on your right to ruddy Antares (the star at the heart of Scorpius, the scorpion) on your far left. Saturn is also, less famously, an icon of mortality. It…

The dark clouds of a supercell thunderstorm make for a menacing presence over an isolated dirt road in eastern Colorado, as seen by storm photographer Mike Hollingshead. A supercell is characterized by a deep, persistently rotating updraft called a mesocyclone, which can make the storm look like a flying saucer or a mother ship. Supercells are commonly seen in the Great Plains, and they can produce tornadoes. “Nearer the storm, the inflow winds get quite high. They are like a huge vacuum,” Hollingshead said. He recalled hearing tornado sirens while he fueled his vehicle in Limon, Colo., before he took this photo on a late spring day.…

What determines if an individual B-cell divides, produces an antibody or evolves? Prevailing theories suggest that B-cells react to external cues, such as hormones, but some Australian researchers now believe that the driving forces may be, at least in part, internal. Immunologist Phil Hodgkin of the Walter and Eliza Hall Institute of Medical Research says the immune system has a sort of default allocation of B-cells corresponding to the various possible outcomes. Each B-cell’s basic fate is sealed, in other words, at the outset. Hormones, then, merely stack the deck in favor of specific outcomes. By devising mathematical models to accurately predict the probability of a B-cell’s behavior, the researchers hope to design new vaccines and immune therapies for diseases such as chronic fatigue syndrome.…

RESEARCHERS HAVE DISCOVERED THAT a quick study of the hands — more specifically, the lengths of the index and ring fingers — can tell a lot about a person’s personality and risk of disease. Of course, your digits don’t actually control these issues; it’s closer to the other way around. In boys, “during fetal development there’s a surge in testosterone in the middle of the second trimester” that seems to influence future health and behavior, says Pete Hurd, a neuroscientist at the University of Alberta. One easy-to-spot result of this flood of testosterone: a ring finger that’s significantly longer than the index finger. Scientists are not at the point where they can factor in finger length to arrive at a diagnosis, but they’ve gathered evidence that shows how this prenatal…

CONVENTIONAL WISDOM It’s best for gorillas if they have little to do with humans. CONTRARY VIEW Tracking great apes for eco-tourism purposes can protect the species. For years, scientists have attached tracking devices to a variety of animals, but they have mostly steered clear of tagging great apes. In recent years, conservationists have worried that habituating gorillas, specifically, to humans is unwise since we are among the greatest threats to the species’ survival. But last year, primatologist Peter Walsh of the University of Cambridge began a new approach to gorilla welfare: He placed a black plastic belt featuring a VHF transmitter around the ankle of Kelle, a 16-year-old male gorilla. Kelle, who lives in a cage in the Congo, will eventually be “reintroduced” to the wild. Walsh plans to use…

THE GREAT AMERICAN JET PACK by Steve Lehto What happened to the flying cars the future promised us? And while we’re at it, where are our jetpacks? Lehto’s detailed chronology of “individual lift devices” is on the dry side, but you learn the sober truth about why these machines never took off: Flight times were measured in seconds rather than minutes; the devices often cost as much as a luxury car; and there was no elegant solution for a malfunctioning jetpack in midair. Until these engineering obstacles — among many mentioned in the book — are overcome, don’t expect personal flight to become a reality anytime soon. DAVE LEE THE ORIGIN OF FECES by David Waltner-Toews When veterinarian and epidemiologist Waltner-Toews persuades guides on an African safari to make a…

National Bike Month Get some exercise, reduce your carbon footprint — and take the kids along for the ride! Bike to School Day is May 8; Bike to Work Week is May 13-17. bikeleague.org/programs/bikemonth 11 Chill Out Try an interactive ice core model and a walk-in ice cave with crawl spaces for kids in a glacier exhibit opening at the Museum of the Earth in Ithaca, N.Y. museumoftheearth.org 5 Eta Aquarid Meteor Shower Peaks Look to the southeast before dawn for this display, which appears to radiate from the constellation Aquarius. astronomy.com/etaaquarids2013 4 NatureFest 2013 The Hagley Museum and Library in Wilmington, Del., celebrates spring with a host of activities, including a giant anthill that kids can help build and then “forage” around for snacks. hagley.org Picking Your Mother’s Day…

Growing up in southern Vermont, Richard Prum developed an ear for birdcalls and learned from the ladies of the local garden club how to tell a warbler from a migratory hawk. Opening a field notebook at random, the Yale University evolutionary ornithologist puts his finger on the day — Nov. 17, 1974 — when he first went bird-watching at the ocean and added 20 new species to his “life list,” bringing the count to 182. That day in the seventh grade, he says, “was the greatest of my life. I’ve spent a huge amount of effort reliving that in greater depth.” The thrill of the hunt has never faded. After graduating from Harvard in the 1980s, he set off to study South American manakins, whose courtship behaviors had never been…

Dark energy and dark matter are two distinct but major components of our universe. The use of “dark” in their names refers only to their mysterious nature, rather than any shared qualities. Here is a breakdown of the dark and visible components of the cosmos.* Normal Matter 5% of the Universe Made of the atoms that comprise our visible universe — everything from stars to planets to people. Gravity attracts it, pulling it in on itself. Dark Matter 24% of the Universe As with ordinary matter, dark matter is tugged inward by gravity. But it does not absorb or emit light, making it hard to track down. No one knows what it is made of, but theorists propose a combination of undiscovered subatomic particles and ordinary matter too dim to…

One form of epigenetic change occurs when molecular structures like methyl groups attach to genes, altering their expression. The abundance of methyl groups can be increased or decreased by infection, environmental exposure or life experience. A methyl group (Me) is an organic compound consisting of one carbon atom bonded to three hydrogen atoms (CH3). When a methyl group becomes attached to the nucleotide base cytosine, the DNA has been methylated. Methyl groups can attach to DNA for life, changing the activity of any gene involved. Behavioral traits associated with those genes are likewise changed and can be transmitted across generations. Methyl groups attach to DNA, which is wrapped around a molecular spool called a histone. Histones are the units that make up chromatin; chromatin includes DNA and non-histone proteins as…

AT A THINK TANK MEETING about autism several years ago, molecular geneticist Simon Gregory spoke with mainstream and nonconventional doctors about oxytocin, the so-called “love hormone” that some doctors were using to treat symptoms of social disconnection in children with autism. Asking for a show of hands, Gregory was stunned to see that about a fifth of the attendees were supplying oxytocin nasal sprays to their young patients. Yet safety data were scanty, and “it was pretty evident there wasn’t any standard of care for autism,” Gregory says. “Some people were using once a day, others twice. There was no metric of successful treatment. It’s the Wild West.” Until recently, most studies examining oxytocin treatment for autism have used small sample sizes and involved only one or two hits of…

1. Here’s the bald truth: Fur and hair are essentially the same thing, constructed of identical protein building blocks called keratin. 2. All mammals have hair at some point in their lives, be it the fuzz on a newborn whale, a shield of hard porcupine quills or your long locks. 3. Insects can wear it, too. The microscopic belly hairs on the male freshwater Micronecta may help amplify its mating call. Some scientists think that when the bug rubs its penis against the tip of its abdomen, the hairs trap air and sound, making it the world’s loudest animal relative to its size. 4. The leg hairs on hunting spiders and crickets function as ears. The hairs sense air motion and can “hear” low-frequency sounds — buzzing bees, for example…