Tabla de contenidos para Winter 2018 en Popular Science

NO, THAT’S NOT A MINI maelstrom tearing up your stomach. It’s one of the most incredible chemical symphonies on our planet: the human physiological response to danger. Your endocrine system dumps adrenaline, dopamine, and other hormones into your blood, which ratchets up your senses (enhance!), and tells your heart to start feeding your muscles extra juice. Your respiration increases to take in more oxygen. Coiled for imminent action, your body is primed to fight—or get the heck outta there. You are now superhuman. At least, temporarily. We share this transformation with animals across the natural world, twirling between routine and high alert. As you examine the causes and effects of this fear dance, you can’t help but notice that one creature’s danger is just another’s afternoon snack. Or, for some…

DEATH CAN COME IN MANY forms, avocados included. If we can stomach enough of them, many of our daily foods are lethal. Down 30-plus glasses of water in a few hours, for instance, and you’ll do yourself in. (One major cause of MDMA-related deaths: water intoxication caused in part by drug-induced extreme thirst.) Of course, the human stomach usually doesn’t hold much more than 4 cups, but the toxic effects of overindulgence can build up as your intestines move the food along. Here’s how much you’d need to eat of a few foods to flirt with fatality. BEEF LIVER Organ meats pack more nutrients than muscles. Livers in particular contain so much vitamin A that overindulgence overloads our own livers—and increases intracranial pressure to hazardous levels. WATERMELON Heaps of any…

YOU PROBABLY DON’T SAVOR THE AGONY OF A WELL-STUBBED TOE, BUT PAIN IS a boon. Stings teach us to avoid similar dust-ups in the future, but entomologist Justin Schmidt refuses to heed the warnings. He’s been poked at least 1,000 times in the name of the Schmidt Sting Pain Index, a scale that objectifies the intensity of our boo-boos, so he’s got a sommelier’s palate for pain. Here’s a taste of some of his most delectable entries. PAIN LEVEL 1 SWEAT BEES “Light and ephemeral, almost fruity. A tiny spark has singed a single hair on your arm.” LITTLE WASP “Sharp meets spice. A slender cactus spine brushed a buffalo wing before it poked your arm.” INDIAN JUMPING ANT “Ah, that wonderful wake-up feeling, like coffee but oh so bitter.”…

LOGGING IS THE MOST DANGEROUS CIVILIAN JOB IN THE U.S., thanks to hazards like heavy machinery and falling limbs. The controlled environment of your backyard can be a safer place for you to take down old trees and chop up the pieces. You might not aspire to be Paul Bunyan, but you can still grab tools—similar to what lumberjacks use in competitions—to become a suburban log slayer. 1 Axe The 6-pound head on the Precision Competition Chopping Axe has a 7.5-inch hand-sharpened edge. The steel slices deep into timber without sticking, and it absorbs vibrations. 2 Gloves A pair of Husqvarna Functional Chain Saw gloves provides extra protection for your nonsawing hand. The left side has two layers of goat leather to shield it during a scrape with a blade.…

FOR SQUISHY BABIES, CARS PRESENT A FATE WORSE THAN diaper rash. Securing kids during a ride took decades to perfect. But figuring out the best way to strap in wee ones is worth it: The right restraint can reduce the risk of death in a crash by 70 percent. Here’s how child safety seats went from precarious to secure. 1920s DIY restraints The first autos prioritized speed and freedom over safety. Parents who needed to contain their children used patchwork solutions, like threading their tykes through this cam strap and faux leather contraption. It’s useless in a wreck. 1930s Bunny Bear Company 1967 Ford Tot-Guard Seat The Detroit automaker was among the first companies to introduce real frontal restraint: padded polyethylene shields to protect a baby’s fragile spine in a…

1 Target Conus catus hunts fish by extending a proboscis, a sort of fleshy harpoon, until it feels the creature’s lateral line—a sensory organ that helps the fish navigate. If the mollusk hits this nerve-filled target, the victim will have almost no chance of escape. 2 Strike Once it identifies its mark, the tiny assassin shoots a hollow, barbed tooth out of its proboscis, spearing the fish’s underbelly and securely hooking into its flesh. The now-stung quarry, thrashing and struggling to escape, is firmly tethered to the immobile hunter. 3 Inject The snail’s hollow tooth acts as a syringe, injecting toxins into the prey. This venom contains hundreds of peptides that work in tandem. First, neurotoxins stop the victim’s nerve impulses from switching off, making it about as stiff as…

USE REAL CREAM People who eat full-fat dairy tend to have less cardiovascular disease. Nutritionists think this effect is probably the result of some combination of lipids being more filling and the microbes in cultured dairy boosting metabolism. EAT YOUR SWEETS It’s harder to fill up on liquid calories. Chewing prompts your body to decrease chemical hunger signals like the hormone ghrelin. Even if a slice of cake and a can of soda have equal sugar content, the confection is more likely to sate you. MAKE BREAD A CHASER Studies have shown that scarfing all your carbs last can cut blood-sugar spikes by 50 percent compared to eating them first. Downing protein ups the production of insulin and incretin, which get your body ready to digest glucose.…

BLISTER Gases made from chlorine, sulfur, or arsenic burn any body part they touch. Used on the battlefield in World War I, their molecules bind to DNA inside cells, including the mucous membrane of the throat and lungs, leading to fluid buildup and deadly infection. BLOOD People need oxygen, and these cyanide-based agents halt the body’s ability to use it. These compounds are mitochondrial poisons. They stop cells from passing electrons to oxygen during cellular respiration. Victims die with bright-red blood in their veins. CHOKING When inhaled, gases such as phosgene disrupt breathing by irritating and corroding the mucous tissues that line the nose, throat, and lungs. Denser than air, a phosgene cloud stays low, where it kills those unlucky enough to learn what it smells like:…

Cities are dense with impermeable sidewalks and streets, so the concrete jungle doesn’t exactly drink up excess water during storms. The result: destructive flash floods. To help, Danish architecture firm Tredje Natur developed Climate Tiles, a modular paving system that collects and distributes rainwater. The slabs resemble a normal paved surface but sport small perforations that funnel storm runoff into horizontally connected channels. The system captures water from roofs, streets, and parking lots, and delivers it to nearby permeable landscapes—such as garden boxes or park spaces—where it can be absorbed. Tredje Natur already gave a few Copenhagen sidewalks a face-lift this year to test out the tiles. But even before that experiment is finished, Toronto and several other cities have put in requests for the rain-draining material. FEED THE…

Each year, poachers traffic thousands of tons of illegal wildlife products through the world’s biggest ports. Detector dogs like the ones I work with are among the most effective means of finding that contraband. Trained canines can sniff out minuscule amounts of ivory, rhino horn, tiger bone, and other illegal products with greater than 90 percent accuracy. But these amazing canine workers will push themselves too hard if you let them. In searching cargo containers, trained animals can encounter toxic substances, dangerous machinery, and extreme heat. Some have even died on the job. There is a way to make things safer (and more efficient): drawing air from shipping containers, running it through scent-trapping filters, and then giving that odor to sniffer dogs n a controlled environment. That way, customs officials…

IN 2011, AN OUTBREAK—NOT OF DISEASE, BUT OF TORNADOES—SLAMMED THROUGH a large swath of the Southern and Eastern U.S. The region saw 64 individual twisters on April 25, and another 50 the next day, but the worst still lay ahead. A head-spinning 199 tornadoes touched down on April 27, killing 316 and injuring almost 3,000. To compare this cluster to others, meteorologists use the Destruction Potential Index. DPI is the sum of each individual storm’s destructive capacity, which weather-folk quantify by multiplying each tempest’s wind power by the area it hits. April 27’s outbreak reached 21,980. That’s three times the next-most devastating event in 2010. Disasters like these are getting worse. From 1954 to 1963, the average outbreak—a sequence of six or more F1 or greater tornadoes that begin within…

THE VISCERAL URGE TO FLEE ROVING sharks has kept us safe for millennia. So it makes sense that 25.4 percent of us fear these toothy predators, despite zero Americans dying in an attack in 2017. Other terrors aren’t so obviously rooted in evolution, but pack some of the common ones into a house—as we did—and you’re bound to find something to rattle your bones. 1 Heights: 28.2% We’re not born acrophobic, but we learn to be early on. Even in our largely cliff-free lives, a fear of heights remains so fundamental that 9-month-old babies avoid drop-offs when crawling. 2 Reptiles: 23.6% Each year, 100,000 people die from snake bites, but it could be worse. Humans are especially good at spying slitherers: Even in our peripheral vision, we’re better at spotting…

EVERY PLANE CRASH GETS A NEWS SPOT, BUT THE 100-PLUS vehicular deaths that occur each day in the U.S. rarely attract attention. Our familiarity with driving makes us feel safe. But operating a 2-ton metal tank running on combustible fuel is risky. Even walking isn’t safe anymore: Pedestrian deaths are up, thanks in large part to the recent supremacy of the SUV, whose taller profile is more likely to land a fatal blow to the chest than a glancing one to the knees. Here, we show how those strikes fit into the 42,246 total transit deaths in 2016.…

LISA PRATT WAS NEARLY 2 MILES BELOW GROUND IN A SOUTH African gold mine when the lights went off and the air stopped moving. Power had cut out, along with the reassuring roar of the ventilating fans that regulate the mine’s methane and carbon monoxide levels. Pratt, then an Indiana University geology professor, was hunting for evidence of life-forms capable of surviving in extreme dark, salinity, and temperature. As miners began to pour from a crease in the rock above her and run for the exit, it was clear that humans weren’t on that list. “It was not a good moment,” she recalls of that day in 2001. “I honestly thought that might be the end of the line.” Today, Pratt’s work in such environments has led her to a…

ANYONE WHO VENTURES FAR INTO BACKCOUNTRY mountains—or even skis off-piste at a resort—should know what they’re getting into. Slides kill more than 150 people worldwide every year, doing in snowmobilers, skiers, and snowboarders. But carrying the right gear (and taking a safety class) will make those epic, swooshy descents safer. These tools will help you get rescued—or save a teammate—in a snowfall emergency. 1/Backpack A folded bladder inside the Mammut Light Removable Airbag 3.0 embiggens you once it’s deployed, so ideally, you’ll float at the top of a snow stream. Yank the handle on your left shoulder to trigger an air canister and inflate the nylon balloon in three seconds. 2/Beacon The three antennas in the Black Diamond Recon BT unit transmit and receive radio signals on a dedicated frequency.…

THE DUPONT TYCHEM 10000 hazmat suit is overkill for just about every situation. That’s the point. The getup blocks more than 320 nasty chemicals for at least 30 minutes. Some, such as the VX nerve agent (a deadly weapon), won’t breach it for eight hours or more, which is why first responders don the garments when wading into clouds of noxious death. Here’s how it keeps its occupants from melting. Shell The suit is a sandwich of materials. The middle layer is roughly ⅛-inch-thick puncture-resistant polypropylene, and a coating on both sides includes dozens of plastic polymers. Each of those has its own protective responsibility, like stopping sarin gas. Visor The face shield gives rescuers a 220-degree field of view, and it leaves enough room for a scuba-style respirator to…

YOU MIGHT NOT THINK OF INTERNET oversharing as a lifesaving habit, but maybe it is. For more than a decade, epidemiologists and data scientists have scanned our search-engine queries and social-media posts with the goal of discerning who is infected, what they have, and where they live. But deriving meaning from our consultations with Dr. Google faces an ironic obstacle: For all our copious snaps, selfies, and status updates, we’re just not sharing enough to consistently forecast disease outbreaks—including the flu. Of course, influenza’s reign of terror started long before the birth of our modern social networks. A hundred years ago, the infamous “Spanish flu” spread rapidly around the world, infecting a third of the population and killing at least 50 million people. With the rapid evolution of the virus,…

There’s no shortcut to a healthy diet. Eating balanced meals, tons of fruits and veggies, scant fatty red meats, and no processed junk food requires time and planning. Americans find regimens with strict rules (no carbs! high fat! eat all the apples!) and big weight-loss promises far more alluring. Forty-five million of us will try such a scheme each year, and many will go to extremes. These drastic plans aren’t just useless—most people gain back the pounds—but they also can damage our vital systems. We analyzed how five of today’s popular food trends throw the body out of whack. RAW This diet is exactly what it sounds like: You eat nothing cooked. Seem doable Try downing an entire crudité platter, warns Christopher Gardner, a nutritional scientist at Stanford University. Taking…

A.D. 256 To invade the Roman-held city of Dura Europos, in what is now Syria, Persian soldiers dig tunnels to destroy the town’s walls. The Romans bore their own shafts to stop them, but the Persians, in one of the earliest documented uses of chemical weapons, ignite sulfur and pitch, creating sulfur dioxide gas and taking out 20 of their foes. 1915 In the first large-scale use of chemical weapons, the German army—looking to break Allied lines along the Western Front—releases 170 metric tons of chlorine gas during the Second Battle of Ypres, in Belgium. The heavier-than-air substance drifts in a miles-long cloud into French trenches, asphyxiating thousands of troops. 1941–1945 The Nazis discover through human experiments that Zyklon-B—a hydrogen cyanide originally intended as a disinfectant and insecticide—is an…

I regularly venture into the Costa Rican jungle to study poison frogs. These little guys don’t make their own poison; instead, they get toxins from the mites and an ants they eat. When the mother has tadpoles, she feeds them unfertilized eggs with the same poi poison inside. I wanted to see whether this defends the tadpoles against predators such as snakes and spiders. We tested snakes in the lab, but tropical banana spiders act weird in captivity. You have to observe them on their own turf—the jungle at night. You shine a headlamp around, and their eyes reflect a blue sparkle. Then you tempt them with a tadpole on a stick and hope they don’t run at you. They’re massive—the size of tennis balls—and hairy, with venomous fangs. I…

HUMANS HAVE BEEN JUMPING, SLIDING, and explosively ejecting from imperiled airborne vehicles since World War I. But clearing crewmembers from doomed planes soaring as high as 80,000 feet—without killing them—has taken more than a century of refinement. Now, the most advanced ejection seats boast survival ratings above 90 percent. This is how we got there. 1975 Electric feel McDonnell Douglas’ ACES II became the Air Force standard, replacing a hodgepodge of seats by different makers. It featured quick-firing, rocket-powered chutes, and was more reliable—the first to time ejection sequences electronically instead of using mechanical or pyrotechnic delays. LATE 1960S A better handle Once aviators donned helmets, there was no need to lower protective face screens before skedaddling. Martin-Baker found it speedier to trigger escape mechanisms with a handle between pilots’…

Of the millions of kids pinging soccer balls around at weekend tournaments, only a small fraction will make it to a Division 1 college team. Just a sliver of that group will reach the pros. Increasingly, those long odds push athletes (often at the behest of parents) to select a single sport in order to grind out a competitive edge. But mounting evidence shows that clearing a child’s schedule of all other recreation might sabotage their shot at the big leagues. Players are picking their games earlier and earlier. The average high-school athlete in 2016 had focused on a single sport since age 12, two years younger than those in college that same year. To compete, the logic goes, tykes need to focus on one thing as soon as possible,…

1 Amygdala Before you consciously process a problem, this almond-shaped brain region activates and begins to amp up the sympathetic nervous system’s fight-or-flight response. 2 Hippocampus and frontal cortex The rational centers of our brain kick in, analyzing whether the perceived visual or auditory input shows a true danger. 3 Cardiovascular system Stress hormones increase your heartbeat and breathing rate while dilating the tiny airways in your lungs. This allows more oxygen to reach your muscles. 4 Endocrine glands Signals from the amygdala hit the hypothalamus, which starts a cascade of activity throughout the endocrine system. The result: a surge of adrenaline and cortisol. 5 Gastrointestinal system Fear really can make you poop your pants. That and retching may be side effects of shrinking blood vessels in the GI tract—diverting…

PERMAFROST ISN’T JUST CHILLED DIRT: IT’S COLD storage for everything from mammoths to the microbes inside them. Though any soil that stays frozen for at least two years is technically permafrost, the frigid layers can be tens of thousands of years old and as thick as 5,000 feet. But climate change is warming the Arctic twice as quickly as any other place on Earth, causing some strange threats to emerge. While many of these artifacts might not do any damage in the modern, melting world, some could be bad news. 1 Exhumed fumes The scariest entity to emerge from the melt so far is methane, a greenhouse gas 30 times more potent than CO2. Released when formerly frozen matter decomposes in thawed tundra, the gas boosts atmospheric temperatures, defrosting more…

SHARP BLADES ARE SAFER. STRUGGLING TO FORCE A dull edge through veggies or fabric makes you more likely to slip and take a bloody trip to the ER, with a fingertip on ice. Instead, wield these cutting tools, and their honed, tough blades, with joyful efficiency—and care. Scissors To triple the strength of its Titanium Scissors, Fiskars coated the stainless-steel choppers with a layer of its namesake metal. The 8-inch-long prongs won’t dull or ding, even after an unfortunate encounter with a staple or pin. Pocketknife Sometimes you need to bust open an Amazon box or chop an onion on a camping trip. The Benchmade 535 Bugout folding knife hides a 3.24-inch steel-alloy cutter in its synthetic resin handle. As a result, the entire tool weighs less than 2 ounces.…

“IT BEGAN THREE AND A HALF BILLION YEARS AGO IN A POOL OF MUCK, WHEN A MOLECULE MADE A COPY OF ITSELF AND SO BECAME THE ULTIMATE ANCESTOR OF ALL EARTHLY LIFE. IT BEGAN FOUR MILLION YEARS AGO, WHEN BRAIN VOLUMES BEGAN CLIMBING RAPIDLY IN THE HOMINID LINE. FIFTY THOUSAND YEARS AGO WITH THE RISE OF HOMO SAPIENS. TEN THOUSAND YEARS AGO WITH THE INVENTION OF CIVILIZATION. FIVE HUNDRED YEARS AGO WITH THE INVENTION OF THE PRINTING PRESS. FIFTY YEARS AGO WITH THE INVENTION OF THE COMPUTER. IN LESS THAN THIRTY YEARS, IT WILL END.” JAAN TALLINN STUMBLED ACROSS these words in 2007, in an online essay called “Staring into the Singularity.” The “it” is human civilization. Humanity would cease to exist, predicted the essay’s author, with the emergence of…

VINEGAR In the 19th century, Lord Byron ate mostly taters and vinegar to stay slim; many still sip the apple-cider variety for the same effect. The logic: Acetic acid inhibits gut enzymes that digest starch. Dieters do slim down but also risk vocal-cord spasms, throat and stomach injuries, and tooth erosion. JUICE Liquid fasts trace their origins at least as far back as the Master Cleanse, a 1940s mix of lemon, cayenne, and maple syrup. Though modern cleanses do add real produce, straining out the flesh ditches the fiber and some vitamins. Results are fleeting: It’s all just water weight. MEAL BARS Restricting calories by swapping meals with cookies and bars has been popular since the 1960s. Preportioned foods are an easy way to check intake and…

CHALLENGE: FLOODING LOCATION: WORLDWIDE As Hurricane Harvey demonstrated in 2017, huge swaths of the U.S. are increasingly prone to severe storms that knock out power and flood hundreds of thousands of homes. Architects have taken note, creating new types of floating and amphibious homes worldwide. Here are some of their protective features. MOVING FOUNDATIONS One of the ways to safeguard a house from floods is to move it up and out of the way. Dutch architect Koen Olthuis has designed floating homes in the Netherlands, Dubai, and China that can rise in order to dodge an encroaching deluge. Some of these houses rest on hydraulic systems that can lift them up to 40 feet above stormy waters and remain stable even in winds up to 156 miles per hour.…

I used to fight wildfires with the Forest Service in California, but now I study them. Often, ignition is straightforward: Humans set fire while doing something not so smart. But some infernos have other causes. While I was in grad school in Nevada, I was puzzling over how flames start in sagebrush, plant much smaller and less dense than a tree. Scientists know lightning is the culprit, but the exact mechanism is a matter of debate. One clear day in 2005, I was out hiking in the Santa Rosa Range. I noticed a giant dark cloud moving in, and I hightailed it out of there; you don’t want to be the tallest thing on a mountain in a lightning storm. Just as I got back to the car, the wind…

From the landmark book Grow Young with HGH comes the most powerful, over-the-counter health supplement in the history of man. Human growth hormone was first discovered in 1920 and has long been thought by the medical community to be necessary only to stimulate the body to full adult size and therefore unnecessary past the age of 20. Recent studies, however, have overturned this notion completely, discovering instead that the natural decline of Human Growth Hormone (HGH), from ages 21 to 61 (the average age at which there is only a trace left in the body) and is the main reason why the the body ages and fails to regenerate itself to its 25 year-old biological age. Like a picked flower cut from the source, we gradually wilt physically and mentally…