Sommaire pour December 2019 de Discover

I remember, as a 7-year-old in the 1970s, playing in my room for hours with a foldout Holly Hobbie gazebo made of heavy bookboard. The small doll was so cute, in her patchwork dress and bonnet, hanging out in the various watercolor worlds that spilled from the white gazebo in the middle. But then along came Hello Kitty. The classic, simple line drawing of her oversized head, button nose and wide-set round black eyes exemplified cute. In my 9-year-old brain, Hello Kitty ruled, and I cherished the pencils, notepaper, stickers and especially a wee vinyl bag. Forty years later, Hello Kitty and her cute parade endure — my 7-year-old niece is a big fan. She’s drawn to the character, and many others like her, for likely the same reasons I…

AS REPORTS OF CORAL REEF die-offs rolled in year after year, marine biologist Raquel Peixoto couldn’t help but feel inundated. Mass reef bleaching events were already five times more common by 2016 than they’d been in the 1980s — a pace that has continued with ocean warming trends, which only exacerbate the die-offs. That’s a big problem for the larger ocean ecosystem, since coral reefs support thousands of fish and invertebrate species — more than any other undersea environment. With images of corals’ dead white skeletons haunting her, Peixoto started brainstorming solutions. “Trying to do something,” she says, “makes me less depressed.” At some point, a thought occurred to her. What would happen if she dosed threatened reefs with “coral probiotics” — strains of beneficial bacteria known to support coral…

Handprints on Hubble: An Astronaut’s Story of Invention By Kathryn D. Sullivan Retired astronaut Sullivan played an integral role in opening a window to the universe through the Hubble Space Telescope — but that’s only part of her story. The first American woman to walk in space, Sullivan recounts growing up with very different plans, why she eventually turned her eyes to the stars and how rewarding her journey has been. Our Wild Calling: How Connecting With Animals Can Transform Our Lives — and Save Theirs By Richard Louv More than a decade ago, veteran journalist Louv coined the term nature-deficit disorder to describe how human health suffers without a regular and real connection to the wild world. Now, Louv flips the equation, arguing that the health of the planet…

Alex, a 30-year-old attorney and self-described fitness nut, was deeply frustrated. He had come to me for an evaluation after his third episode of acute pancreatitis. Each of the episodes had been intensely painful and landed him in the hospital for several days, where he hadn’t been allowed to eat anything and had received copious painkillers. Internists hadn’t found anything so far, so I had been asked by his referring doctors to look deeper to find a cause. While most people think their stomach digests their food, in reality, the pancreas does most of this work. This organ sits behind the stomach and just in front of the spine, and is connected to the small intestine via several fine ducts. In addition to sodium bicarbonate (which the body uses to…

Mammals need mommies. (For many mammal species, fathers also play a role in parental caregiving.) So it’s no surprise that kindchenschema, or “baby schema,” shows up across Mammalia. This suite of facial features, including large eyes and a small nose and mouth, elicits a caregiving response that’s handy if you’re an infant dependent on getting that care. But what about non-mammals? University of Michigan evolutionary psychologist Daniel Kruger decided to investigate whether kindchenschema might also be present in birds and reptiles that provide parental care. Kruger’s team showed college students images of baby birds and reptiles from eight different species. Four of the species were what’s called semiprecocial, meaning they required some parental care. The other four were superprecocial and independent from birth, no mom or dad needed. Participants answered…

In the late 1980s, scientists got their hopes up that MACHOs — gobs of normal matter that were simply dim and tough to detect — could answer the dark matter question. These objects would range from planets to failed stars to black holes. Unfortunately, well-supported Big Bang models struggle to produce anywhere near enough regular matter for MACHOs to fill the cosmic ledger. More damningly, observations have consistently ruled out any vast populations of clandestine black holes, which should give themselves away when their gravity bends background starlight. An October 2018 study took out the last leg for MACHOs to stand on, putting serious constraints on the possibility of primordial black holes — hypothetical monsters born in the early universe — being the last plausible reservoir of significant unaccounted-for matter.…

Somewhere in the warm, clear waters off the coast of Australia, a mature bottlenose dolphin is swimming with her daughter. It’s dinnertime. But, instead of chasing down a fish in open waters like she usually does, mom swims over to a basket sponge growing on the ocean floor. In a deft move, she breaks off a piece of the sponge, then fits it snugly over her rostrum — her beak. It’s hard not to wonder what that curious, watchful youngster might be thinking about all this. Are you going to eat that sponge? Are we playing? With the sponge secured on her beak, the older dolphin starts sweeping her head back and forth across the ocean floor. She’s looking for bottom-dwelling fish like the sand perch, which hide themselves on…

EVER CAUGHT A GLIMPSE of the man in the moon? Then you’ve experienced pareidolia — the tendency to perceive patterns where there are none. Faces are the most common shape people see, likely because mugs matter so much in our social species. But the phenomenon, pronounced “parr-i-DOH-lee-uh,” goes beyond faces. We humans can spot just about any shape in nearly anything: Maybe you see a deformed version of your state in your latte foam, or perhaps those clouds are two dinosaurs duking it out. Pareidolia even extends to auditory stimuli, when people misinterpret arbitrary sounds and noises as something meaningful, like voices or music.…

Hop, Skip, Go: How the Mobility Revolution Is Transforming Our Lives By John Rossant and Stephen Baker Getting from Point A to Point B has always been a matter of time, space and budget. Urban mobility expert Rossant and tech writer Baker break down the promise — and potential pitfalls — of how we’ll do it in the future. Are Men Animals? How Modern Masculinity Sells Men Short By Matthew Gutmann Anthropologist Gutmann tackles myths and misunderstandings about testosterone, gender, violence and a host of other topics that crop up in conversations about the nature of roughly half the population. On Trial for Reason: Science, Religion, and Culture in the Galileo Affair By Maurice A. Finocchiaro Galileo scholar Finocchiaro immerses the reader in the dominant schools of thought during the…

4,600°F The temperature of the upper atmosphere of heavy metal exoplanet WASP-121b. For comparison, Mercury tops out at 800 degrees Fahrenheit. The newly found planet is so hot, and so close to its star, that it’s being ripped apart by the star’s gravitational pull. Astronomers have been able to observe the metals, like iron and magnesium, that the planet is emitting into space. 205 GIGATONS The amount of carbon emissions that could be pulled out of Earth’s atmosphere if people planted 500 billion more trees. That would be a 25 percent increase in the world’s total forests and would cut CO2 by 25 percent. But critics point out we’re already using that land for other things, including grassland ecosystems. 12% How much more likely native Germans waiting on a train platform…

Fossils, artifacts and human DNA sketch out the story of our evolution — but fail to capture everything. To fill in the gaps, some researchers are consulting our tiny hitchhikers: lice, mites and other parasites that latched onto our lineage long before Homo sapiens even evolved. “If they’ve gone through the same history,” says University of Florida biologist David Reed, “[they] must have something to say about that history.” It turns out the parasites can reveal aspects of our past — including the invention of clothing, unknown migrations and close encounters with other species — overlooked by traditional lines of evidence. OF LICE AND MEN After studying lice on gophers as a graduate student, Reed turned his attention to hominins — species on the human branch of the primate family…

As many of us struggle with work-life balance, economic uncertainty and the ever-faster, ever-stronger fire hose of information, “cute breaks” are common. Even the researchers who study cuteness do it. “On a Monday morning that’s grim, I’ll put on the ‘four laughing babies’ video,” says neuroscientist Morten Kringelbach, referring to a former winner of America’s Funniest Home Videos that features, yes, four babies laughing. And that’s it. For more than a minute. “Suddenly, you think, ‘Can life get any better?’ ” However, the same cuteness that helps you get through a difficult day may prevent you from moving on to better things. “You endure,” says social psychologist Kamilla Knutsen Steinnes. “This is a new strategy by a lot of employers, such as having dogs or cats in the workplace. It…

The only force definitely felt by both matter and dark matter is gravity. Accordingly, some researchers have created gravity only models of the dark stuff, dubbed GIMPs: gravitationally interacting massive particles. One of the concepts isn’t new to physics — it simply submits that black holes actually have all that missing dark matter bound up within them and act in essence like ginormous particles. Alternatively, physicists have conjured GIMPs as elementary particles required by theories of our universe that include an extra fifth spatial dimension. Best we can tell, though, there’s still just the three, plus time. Perhaps the wildest horse in this herd, though, is Planckian interacting dark matter (PIDM). It consists of individual particles that each could weigh as much as 10 quadrillion protons. PIDM that spawned in…

NGC 7773, captured here in a recent Hubble Space Telescope photo, might just be the ideal example of what astronomers call a barred spiral galaxy. Its tendril-like arms spiral out from the center, a star-filled rectangular smudge, or “bar.” Astronomers have observed these central features more often in older galaxies (like our own Milky Way) than in younger ones, so they suspect the formations develop as the star systems age. Over time, the gaseous materials that create stars migrate in from the spirals and converge in the central bar, powering new stellar birth.…

In any creature with eyes, optic fibers serve as speedways of information between the retina and the brain. To take this photo of the ocular highway in a healthy mouse, scientists at the National Center for Microscopy and Imaging Research in San Diego used a laser scanning microscope, capturing the colors of cellular components stained with vibrant dyes. Optic nerve fibers (red) form the ocular roads, glial cells (green) wrap around them for protection and blood vessels (blue) bring them oxygen and other nutrients. Images like this help researchers understand how tumors can affect these tissues, and how best to fight the unwanted growths.…

It’s 1988. A young scientist sets up a simple evolution experiment involving small colonies of bacteria growing in flasks. To be safe, he tries out two variations, each with slightly different parameters. Though they exist side by side, these two experiments are essentially parallel universes, mirrored versions of each other with just a few pieces swapped out. One of the experiments fails within months — the bacteria quickly stop growing like they should. But the other set of colonies prospers. The experiment eventually evolves into one of epic proportions — one that will offer unprecedented insights into the mechanics of evolution and yield a sprawling ecosystem of laboratories and researchers. Was it the small disparities between the two experiments that made such a big difference? Or was it just dumb…

1 Super-retailer Amazon is all about volume — during its annual Prime Day sale last July, the company says, it sold more than 1,000 items per second. When it comes to moving mass amounts, however, that’s nothing compared with the Amazon River. 2 Depending on the season, the mighty South American river pours more than 10 million cubic feet of water per second into the Atlantic Ocean. 3 Such a colossal water discharge would typically prevent reefs from forming in a river’s mouth due to changes in water properties, like salinity. But that’s not the case for the Amazon: A unique reef system stretches nearly 3,700 square miles into the Atlantic. 4 The reef occurs in the river’s plume, where freshwater currents mix with ocean water. There, the Amazon feeds…