Sommaire pour September/October 2020 de Discover

BRILLIANT BIOFILM This would look pretty cool on a T-shirt, right? The psychedelic pattern is actually an adhesive cluster of microorganisms (in this case, Vibrio cholerae bacteria) called a biofilm. Consisting of both living cells and the extracellular structure they create, the biofilm sticks to different surfaces, sometimes forming threedimensional wrinkles as it grows. In a recent study, scientists at Princeton University examined how these cellular crinkles coalesce. The research team found that on soft surfaces, some biofilms start out flat before becoming creased due to friction, generating zigzag patterns that look like spokes on a wheel. They say the findings could help scientists prevent biofilms — and the bacteria they harbor — from spreading where they aren’t wanted, like in infections or on medical equipment. — ALEX ORLANDO; PHOTO…

“There was no sound at all from the mountain, just those gentle-looking puffs of steam,” says photographer Michael Lawton, recalling his mid-April morning hike to photograph Mount St. Helens. Despite the warning signals — white vapors rising from the summit — Lawton felt no fear: “I remember saying to myself that this would be a good place to see it explode.” With backpack and snowshoes, Lawton and his local mountain guide had trudged for five hours up snowy slopes to reach their mile-high vantage point, about eight miles from the smoldering mountain. Had they been there a month later, on May 18, the date of the volcano’s most violent eruption, they would have had only seven minutes before the onrushing wall of hot gas, ash and rock overwhelmed them. Says…

AS CRAZY-MAKING as staying put can feel, there’s a certain security in it. You know that the fewer people you interact with, the less likely you are to get sick. But as states relax quarantine rules, people now must set their own safety and comfort thresholds as they reengage with the world — a fraught process that requires weighing physical health hazards against mental health needs, social pressures and career goals. Do you risk boarding a plane to visit your extended family for Thanksgiving? What if your boss asks you to mingle with large groups of people, sending your health anxiety into overdrive? Variations in how other people behave in different spaces will complicate things even more. “People are more likely to comply [with] interventions and personal protection measures on…

AS YOU GET closer to Earth’s poles, seasonal swings in temperature and vegetation get increasingly drastic. In many places, snowy winter wastelands alternate with relatively lush summers. That can make life hard for birds, unless they can cope with the weather — and their food sources — changing throughout the year. Birds that can’t handle it migrate to warmer climes for the winter. Those that tough it out year-round tend to have big brains relative to their body size, which help them figure out how to manage life in the changing landscape — or so scientists had thought. But Trevor Fristoe, who grew up in Alaska, knew that small-brained birds could also thrive in such environments. An avid birder, Fristoe is an ecologist and evolutionary biologist at the University of…

For 2-year-old Farida and her family, the trip to Egypt was a pleasant prelude to what would turn into a hard few months. She spent time with relatives in Cairo, visiting her grandparents for the first time. She enjoyed lots of traditional food. She even went to visit her father’s hometown, a rural area several hours south of Cairo. But the long getaway, which lasted from after Christmas until early spring, would be the last time her family was able to relax for months. As April rolled around, Farida began running fevers. They began, on and off, without any other symptoms. After two weeks, her mother took her to the family doctor, who prescribed antibiotics for a presumed ear infection. But the fevers didn’t subside. When the family returned a…

Back before ecodeath movements or Civil War entrepreneurs, the city of New Orleans had already solved the mortal burial problems of land area, nutrients and smell. In the 1800s, New Orleans endured several disastrous plagues. Yellow fever killed an estimated 41,000 people, about a quarter of the city’s midcentury population. Water-borne epidemics of cholera and malaria also rippled through the port city. This left New Orleans with a pressing need to develop a solution to the growing body count. With the city famously built around sea level, New Orleans had no way to bury bodies 6 feet under. When they tried, storms would erode away the earth above and send caskets bobbing to the surface. They tried drilling holes in coffins to let air escape and prevent them from floating,…

In the beginning there was Adam. We’re not talking about the first human, but rather the first machine to fully automate the scientific process and make a discovery on its own. Adam looks nothing like a human. It resembles a big box, about the size of an office cubicle. It’s equipped with robotic arms, incubators, a freezer, cameras and other parts to help it do work. Everything it needs to conduct its research is there, including the brain to do it. The man behind the machine is Ross King, a professor of machine intelligence at Chalmers University of Technology in Sweden. He started building Adam in 2004 to study enzymes in yeast, and later created a second robot — aptly named Eve — to search for potential malaria drugs. “Adam…

1 You were learning before you were born: By eavesdropping on their mothers while in the womb, babies pick up the sound patterns of their native tongue. 2 After birth, infants recognize these rhythms and are more attentive to them than the sounds of other languages, prepping for eventual fluency. 3 But infants’ first postnatal teachers are their mothers’ faces: Babies can distinguish their mothers from other women within hours of birth, and discern emotions within days. 4 That ability helps junior figure out whether a new toy is safe or a stranger is to be trusted. 5 This focus on mom has a cost, though. As a child becomes more familiar with their mother’s face, faces unlike hers become more vague, especially those belonging to people of other races…

When Mount St. Helens exploded sideways on May 18, 1980, the dust did not settle quickly. After a 5.1-magnitude earthquake caused the volcano’s summit to collapse in the largest landslide in recorded history, a blast of ash, rocks and hot gas sped out of its north side at over 300 mph. The shock wave flattened the surrounding forest, while mudslides destroyed hundreds of homes. The wind carried millions of tons of ash all across the U.S. In total, the eruption killed 57 people — most of whom suffocated after their lungs filled with volcanic matter. The blast would spark a seismic shift in science, too. Amid the devastation, Mount St. Helens became a living laboratory for the study of volcanic activity. For starters, it showed that a single explosion can…

Archaeologist Annemieke Milks planned to test the ballistic properties of some of the world’s oldest spears. Crafted by Neanderthals 300,000 years ago, the wooden artifacts measure about 7 feet long and resemble oversized broomsticks with sharpened tips. When discovered in the 1990s at a site in Schöningen, Germany, they rested alongside the butchered remains of 35 horses. Apparently, Neanderthals, armed with the spears, had some very successful hunts. But just how fast and far could these ancient weapons soar? Milks wanted the answers, so she commissioned a woodworker to carve replicas from dense spruce. Yet to do the experiment right, Milks needed study participants who could throw like their lives depended on it. Neanderthals were, after all, hunter-gatherers, who killed their daily meals with spears and other primitive technology. Put…

For as long as humans have been alive, they have been dying. And for every different burial practice, there is another culture that deems it barbaric. But the practicalities of nature are what have shaped traditional human funeral practices over time and across the world. For instance, in 19th-century India, honored dead in the Parsi community were routinely placed atop a tower for a waiting throng of vultures. There are still towers of silence in Mumbai today, but not enough vultures to dispose of the bodies. In Tibet, such sky burials still take place, but require someone to dismember the body before it is left for wild dogs or vultures. Sky burials occur at high altitudes where wood is scarce, the soil is too rocky to dig and a colder…

In the early 1950s, well before the AI Dendral started to materialize, robotic lab tools were starting to go mainstream. Automatic titration devices, used in chemical analysis, were sold for the first time. Around the same time, engineers working for the New York Central Railroad created an automated system for lube oil analysis — an easier way to complete a routine task that soon spread to other U.S. railroads. A New York Central passenger train at Rochester, New York, in the early 1950s.…

Every 10 years, Americans undergo a familiar ritual: the U.S. census. Forms appear in the mail and workers start knocking on doors, all to get an accurate count of the U.S. population. The data collected provide a snapshot of the country, allowing officials to understand demographic changes in order to better allocate resources — and representatives to Congress — across the map. A similar process unfolds in astronomy: Every 10 years, researchers conduct their own census of the field to plan for the future. Known as the Astronomy and Astrophysics Decadal Survey — or simply, the decadal — the effort is mandated by Congress, and aims to identify the top priorities in the discipline. (Inspired by the American astronomy decadal, other countries, and some other sciences in the U.S., also…

It’s been almost 40 years since NASA’s Voyager 1 spacecraft soared beneath Saturn’s rings. The Nov. 12, 1980, flyby forever changed our understanding of the planet. The probe discovered three new moons and an additional ring surrounding Saturn. It also learned that the atmosphere of the planet’s largest moon, Titan, is made mostly of nitrogen — like Earth’s. Launched in 1977, Voyager 1 and its twin, Voyager 2, went on to study Jupiter, Saturn, Uranus and Neptune up close, taking advantage of a rare alignment among the outer planets. And while the project was only approved to fly by Jupiter and Saturn at launch, the probes would ultimately complete a planetary grand tour. As Voyager 2 cruised toward Neptune, NASA even expanded the size of its earthbound satellite dishes to…

Imagine a world where, when a person died, they took all their riches with them like the pharaohs of Egypt. If you consider biological material to be of value, this is not so far removed from modern reality, except that instead of gold and silver treasures being buried with us, it’s our nutrients. These riches we hoard in our graves are the mineral building blocks necessary for those still alive — the carbon in our skin, the iron in our blood and the calcium in our bones. These nutrients exist as finite, limited resources in the world. But conventional practices of embalming and cremation prevent their recycling, hindering our ability to give back that which we have attained from other living things. The average human weighs 136 pounds at the…

In February 2013, the Center for Care and Discovery, a 10-story hospital in Chicago, officially opened its doors. As the first patients began to stream in, they brought their microbes with them. They shed bacteria in the lobby, sprinkled viruses around the hallways, deposited fungi in their beds. And they shared these microorganisms with their fellow patients, passing them along to subsequent occupants of their rooms. When a patient moved into a new room, their body was “actually colonized briefly [by] some of the bacteria in the room — the previous occupant’s bacteria,” says microbial ecologist Jack Gilbert, who led a yearlong study of microbes in the new hospital. And that was true even if the room had been cleaned, he says. After one day, however, the flow of microbes…

Six years ago, three Volvo engineers sat on a forest floor in western Sweden, picking twigs off the ground and snapping them in half. “We were in the woods for two days sampling sounds,” recalls Fredrik Hagman, a sound designer at the company. Three hundred sticks later, they returned to the automaker’s headquarters in Gothenburg, Sweden. There, they tweaked the sound and pitch of the twig’s snap to create the click of the turn signal indicator used on Volvo’s new electric SUV, the XC40 Recharge. Car companies have always used sound to enhance a car’s personality and boost the perception of its performance. An effective acoustic signature announces the car long before its arrival, and enthusiasts can identify a car’s make and model — and even the year it was…

It was a crisp night in June, the sky bright from the light of the full moon. I stopped at a gas station to fuel up before heading to the hospital to see my father. Three months after heart surgery, his newly replaced valve had begun driving bacteria into his brain, causing multiple strokes. He was dying. Standing at the pump, I thought about how he would never visit our new home. How we would never dance together again. I paid for my gas, got back in the car and drove out of the gas station — with the nozzle still lodged in my tank. When I stopped the car, an onlooker who had watched the nozzle fly out of my car’s gas tank said smugly, “You’re lucky it snapped…