Popular Scienceの Summer 2019 の目次

WHEN I WAS A KID, THE water cycle blew my mind. I think it was fifth grade science when I learned about the phenomenon through song (perhaps you did too), a musical description of how our planet turns moisture from everywhere into the water we drink. I remember it with a honky-tonk swing that I probably imagined. I’m absolutely sure about one thing: After the lesson, I walked up to the teacher to double-check the facts. “You mean we’ve got all the water we’re ever gonna get?” Yep, he replied. Kaboom. Worldview obliterated. This still amazes me. And water is just one of many resources we’ll never get more of. From the International Space Station to your flat-screen TV to carrots and horses and mason jars, all our planetary riches…

GLOBAL CLEANUPS PULL PLASTIC FROM OCEANS and pledge drives guard rainforests, but grasslands get very little love. Only 5 percent of Earth’s remaining meadows are preserved, making them the least-protected biome. Humans have already destroyed more than 90 percent of the planet’s grass, most of it to produce our food: Grazing alone takes up one-quarter of all land. What’s left is fragile because grasslands’ seasonality makes them vulnerable to climatic changes in precipitation and temperature. This is what remains. BEFORE HUMANS AFTER HUMANS 1. THE SERENGETI TANZANIA This savanna is one of the oldest ecosystems on Earth. Ecologists believe the area’s weather, flora, and fauna have barely changed over the past million years. Though the plain is well-protected by Serengeti National Park and Ngorongoro Conservation Area, the human population is…

MOLECULAR BIOLOGIST Christopher Johnson was schmoozing at a party not long ago, talking with another guest about his research, as scientists often do. Johnson works on breaking down plastics, which tend to be highly resistant to such things. The woman he was speaking with at this particular pre-wedding soiree replied that she felt overwhelmed—hopeless—about the whole situation: how we can’t seem to stop using plastics, how they crowd landfills, how their microparticles permeate the oceans. Overwhelmed, Johnson thought. Hopeless. “I’m a world away from that perspective,” Johnson says, recalling his reaction. That’s because plastics aren’t just happening to Johnson. He’s happening to them. Johnson is a research scientist at the National Renewable Energy Laboratory, and this past year, he and his colleagues created a biological enzyme that can chew efficiently…

The 21 million residents of Florida get the vast majority of their drinking water from two aquifers: The Biscayne, which sits below the Everglades, feeds the south, and the larger Floridian aquifer system supplies areas north of that. If the flow were working properly, the ground would filter rainwater, and the purified liquid would land in our subterranean reservoirs, which humans would then reach via wells and pumps. But our fresh water faces many stresses. A booming population overtaxes wells, and sudden downpours spread pollutants like fertilizer runoff into the supply. All the while, the ocean has advanced farther inland than ever before, pouring saltwater into these struggling reserves. The trend impacts the whole state, but most urgently, it threatens those who tap the Biscayne—the 2.5 million residents of Miami-Dade…

Water Overconsumption, pollution, climate change, and the increasing demands of a swelling population are drying out key agricultural regions like California, the Mediterranean, and Central America. PROBLEM: regular droughts SOLUTION: early-rising plants Since the 1940s, farmers from Texas to South Dakota have relied on the Ogallala aquifer during sporadic dry spells. Now parts of the reserve are getting dangerously low. Agriculture giants Monsanto, Syngenta, and DuPont have engineered plants capable of muscling through drought, but those seeds cost more, and farmers don’t always get the yield they need to justify the price. The problem is these dry-spell survivors often can’t turn off their drought mode fast enough once the weather shifts. The longer it takes for the crops to reopen the pores in their leaves, which close to prevent precious…

In 2010, a friend and I started the Richmond Grows Seed Lending Library. It’s a lot like a regular library, but instead of books, we lend packets of seeds. You can check them out, plant them at home, and harvest new ones that you’re welcome to return to us for the next person to use. A century ago, just about every farmer in this country saved seeds from their crops to replant the following year. Now, most buy new ones each season from big agriculture companies, which engineer them to produce uniform, high-yield harvests. But breeding for consistency rather than biodiversity can make plants more susceptible to various diseases and pests. I found this out after taking a permaculture design class taught by Christopher Shein, who started one of the…

1 Spotting sperm VICTOR W. WEEDN, FORENSIC SCIENTIST AT GEORGE WASHINGTON UNIVERSITY Sperm are hard to find under a microscope, so we use a special dye to turn the heads red and tails green. But the tails often break off, leaving the heads, which, unless carefully examined, look like totally different cells. To make sure we find the sperm, we take it slow. 2 Counting eggs NILAY YAPICI, NEUROBIOLOGIST AT CORNELL UNIVERSITY In an attempt to pinpoint a similar protein found in fruit flies and mosquitoes that could stop skeeters from biting, I genetically modified 400,000 flies and counted, by hand, millions of eggs. This was during graduate school in 2007, but manual tallying is still the quickest method. 3 Tracking tree rings RONALD H. TOWNER, ARCHAEOLOGICAL DENDROCHRONOLOGIST AT THE…

Leather is difficult to mimic without animals, which use up lots of land and water. Instead, we engineer yeast cells that produce collagen proteins as they ferment. We purify what comes out and turn it into a material that tries to imitate a hide. Our team helps companies that want to make leatherlike vegan products. But communication can be difficult. Designers speak about materials based on their instincts about texture and sense of touch—two very subjective things. But scientists want to know about the mechanics, such as tensile strength, which is the measure of how far a substance can bend without breaking. So a brand would come back to us and say, “It needs to feel richer,” and you’d get a room of blank faces from the scientists. They’d ask,…

FANS OF DIE HARD WITH A Vengeance will remember this one: To disable a bomb, Detective John McClane must measure out exactly 4 gallons of water, and place the resulting weight on a scale. His tools are yours: a 3-gallon and a 5-gallon jug—and a single fountain. McClane did it in less than 5 minutes, but we won’t time you. This go-round, lives probably aren’t on the line. THE LAST DROP A) Fill the 5-gallon jug. Use it to fill the 3-gallon jug, leaving 2 gallons in the 5-gallon jug. Empty the 3-gallon jug. Pour in those 2 gallons. Fill the now-empty 5-gallon jug and pour 1 gallon into the 3-gallon jug. There are 4 gallons left in the 5-gallon jug. B) Fill the 3-gallon jug and pour it into…

An orchard in a single tree CLAIRE MALDARELLI IN THE OFFICE COMPRESSING AN ENTIRE GROVE’S WORTH OF fruit into a compact space is difficult, but artist Sam Van Aken has proved it’s possible. Using grafting techniques that date back as early as 1400 B.C., he can grow up to 40 different stone fruits on a single plum-tree frame. To add a branch of peaches, nectarines, or cherries, for example, he collects a pencil-size clipping from the desired tree and transplants the foreign sliver onto a limb or trunk. The DNA of the two species will never mingle, but if all goes well, they’ll produce diverse foods side by side. The only problem? You have to graft, wait, and repeat 39 more times before your personal orchard comes to…fruition. Solar-panel windows…

Mallory Pickett Before she became a freelance journalist, Mallory Pickett earned a Master’s degree in the chemistry of climate change. She’s captivated by the idea that our actions today will affect the Earth we’ll live on tomorrow—specifically, a warmer one. With aerosol particles and ocean acidification on her mind, she wonders what our planet could look like in the wake of the unnatural forces we’ve thrust upon it. “When we talk about climate change, it’s often this simple, monolithic thing,” she says. “But it’s unleashing this whole set of changes.” In her feature story on page 56, Pickett reports on an ecologically catastrophic algal bloom in the Gulf of Mexico that claimed the lives of sea creatures such as manatees, turtles, and dolphins. Its precise causes, and the role…

THE EPA’S MOST RECENT census of U.S. waste tallied 262.4 million tons of new junk in 2015—the weight of about 40 Pyramids of Giza, or 4.5 pounds per person per day. We can recycle about one-quarter of what we toss, but rising costs and trade issues mean some municipalities no longer bother. Even in places that still attempt to keep trash out of landfills and oceans, not all “recyclable” items end up renewed. Here’s how much of that stuff actually makes it back into circulation—and why it’s smart to use fewer disposables, no matter what bin you put them in. Plastic plates and cups Most discarded dinnerware is made of polystyrene resin. It’s so cumbersome (bulky, but light enough to blow away) that no curbside pickups take it. We make…

DEATH MIGHT BE LIFE’S NATURAL AND unavoidable conclusion, but humans have ensured that what happens to our bodies afterward is anything but. For more than a century, the circle of life in the United States has looked more like a horseshoe, with burial practices preventing the Earth from reusing our precious raw materials after we shuffle off this mortal coil. But there are alternatives, and a growing number of future corpses might rot as nature intended. Embalming may be our worst offender. The practice of filling bodies with chemicals like formaldehyde to preserve them dates back to ancient Egypt, but it caught on stateside in the mid-1800s as a way to transport fallen Civil War soldiers. Today, U.S. morticians embalm roughly 1 million people every year. It takes between 3…

YOU CAN MEASURE BAMBOO’S GROWTH SPURTS IN FEET PER day. That rapid expansion makes it a sustainable substitute for the less-earth-friendly materials such as the plastic, metal, and wood we buy every day. Even growing the stuff is a help: The grass’s unique connected root system binds together soil, preventing erosion. These four items come from a panda’s favorite snack. 1 Cutting board Bacteria love hiding places, which is why you don’t want gashes in your chicken-chopping surface. The Royal Craft Wood board’s bamboo material is dense enough that it won’t suck up much moisture. It’s also tougher than plastic, so it resists gouges, where microorganisms can live. 2 Toothbrush A typical chomper cleaner sports a plastic handle, which can take a millennium to decompose in a landfill. California company…

One morning in August 2018, a man named Ralph Breeden telephoned the Florida Fish and Wildlife Conservation Commission to report that a dead manatee was bobbing in the bay behind his house in a quiet Saratoga suburb. Soon, two biologists, Gretchen Lovewell and Rebeccah Hazelkorn, were on their way to recover the corpse in a pickup truck fitted with a portable crane. Lovewell and Hazelkorn are the equivalent of marine EMTs and coroners, performing rescues and necropsies, operations that often require them to handle turtles that weigh more than 200 pounds and dolphins over 6 feet long. They work out of the Mote Marine Laboratory in Sarasota, which the wildlife commission had contacted to collect the carcass. They’re tough women, each sporting marine tattoos (Lovewell has a dolphin, manatee, turtle,…

Burmese pythons have invaded South Florida. In the five years between 2013 and 2018, my team of biologists removed more than 500 snakes (some 12,000 pounds worth) in 55 square miles of wilderness outside Naples, which sits on the Gulf side of the state, not far from the Everglades. The reptiles, primarily the offspring of escaped pets, have made it as far as the Keys and are slithering their way up to the central part of the state, disrupting ecosystems as they go. All our native fauna is on their menu. No one really knows what the future of the Everglades—and beyond—looks like if we can’t get these predators in check. But first, we need to get a sense of how much wildlife they consume as they spread. The state…

It has become increasingly difficult to fix the things you own. Tinkering with your gear or taking it to an independent repair shop—assuming you can find one—often voids the warranty. But device rehab wasn’t always verboten. Communities of fixers still exist around the world, though their numbers are dwindling. In New York City, in particular, entire districts once dedicated to restoration have given way to stores, cafes, and apartments. Throughout the boroughs, skilled techs still toil behind closed doors, where subtle signs and sparse Yelp review pages belie their decades of know-how. SHUTTER ISLAND Husks of vintage film cameras and lenses litter this workbench at Camera Doctor. Owner and technician Frank Rubio has scavenged many of their components for repairs because manufacturers have either disappeared or no longer make replacement…

Earth’s companion is a hot commodity. Teams from China, Israel, India, and NASA all want fresh slices of moon cheese—as do private companies such as Cape Canaveral’s Moon Express. Some of this off-world transit hype is about bragging rights, and some is purely for research. But this global flotilla is also nudging us closer to when we’ll mine the moon. Lunar regolith might bake into bricks, reap precious metals, or refine into fuel and solar panels. Here’s what’s up there that could be useful. 1. Silicon We have plenty of silicon on Earth, but that doesn’t mean it won’t be useful in space. Future lunar settlers could mine and refine it into semiconductors to create solar panels that could power their outposts. The stuff makes up 20 percent of moon…

For decades after they belched their last coal fumes, the cooling towers of the Richborough Power Station loomed over the low landscape of Kent, in the southeast of England, guiding fishing boats into the English Channel. That all ended on the morning of March 11, 2012, when a controlled demolition reduced the 30-story-high towers to rubble, clearing the site for a cleaner future. The building that has risen in their place at the renamed Richborough Energy Park is one very tall story and painted in three layers of green and gray, as if determined to fade into the sky. It buzzes with 1,000 megawatts of electricity—enough to power a million homes—but emits no exhaust and has no need for towers or chimneys. Its energy is not produced here, only passing…

Helium is a little bit sexy, you know? If you immerse some solid objects into a vat of the element, the submersible becomes superconductive—electricity flows indefinitely without generating heat. That’s why helium is great for more than just making balloons float. Its energizing abilities make it ideal for everything from space travel, where it forces fuel into rocket engines, to MRI machines, where it cools the imaging magnets. But helium is also terribly uncooperative. The gas doesn’t combine with any other compound, and Earth’s force of gravity isn’t strong enough to hold it down. Once it enters the atmosphere, it’s gone forever. The only reason we haven’t already run out is that over millions of years, other elements such as uranium decayed and formed helium, which got trapped inside surrounding…

EDGES DEFINE AN OBJECT’S SHAPE. Without them, we wouldn’t know a square from a circle. But we don’t need a complete mold for a figure to take form. A prime example? The eerily vibrant triangle above. In reality, no polygon exists. There aren’t any connecting lines within the sectioned colors to create it. Yet, our brains trick us into thinking that the Pac-Man-like characters are full circles, topped with a 3D triangle. The illusion depends on careful placement. Our minds can make do with scant information, says Christof Koch, chief scientist of the Allen Institute for Brain Science. Here, the Pac-Man shapes sit at the would-be triangle’s edges, so we reckon a polygon is actually there. Such leaps are useful in real life. If someone hides behind a tree and…

MOST OF THE HUES WE LOOK AT THESE DAYS COME courtesy of 16,777,216 alphanumeric keys called Hex codes; tinting your technicolor digital life is as simple as copying a string of characters. But the shades on this page—and all your off-screen belongings—come from resources we must conscript to create our chosen chroma. Affixing color to an object (and making it stick) is tricky business. For most of human history, we’ve derived dyes from nature: People cooked plants and animals until they produced the desired pigment, or mined precious minerals from subterranean seams and ground them into paints. But even once we took to the lab to concoct new colors, some shades remained rarefied. This chart shows a few of the commodities that tint our kaleidoscopic world—and how long it took…

STORAGE IS HARD TO come by aboard the International Space Station. Even if a rocket had room to ferry thousands of pounds of water and oxygen to supply a six-month mission, you’d struggle to find anywhere to stash it. So engineers have devised creative ways to squeeze essentials from astronauts’ sweat, urine, and breath. But we’re not at total recovery yet. Right now, the ISS recycles 90 percent of its water —or more than 1,000 gallons annually—and 40 percent of the oxygen astronauts breathe. The rest comes up on resupply missions. This diagram shows how NASA gets so close to a self-sustaining space home. 1 Astronaut An Earth-bound human uses about 80 gallons of water each day, but an ISS resident stretches just one for drinking, showering, and hydrating food.…

ONLY 60 PERCENT OF THE FOOD WE GROW IN THE UNITED STATES makes it into our mouths. The rest drops out of the supply chain, bit by bit, as grub wends its way to our plates. Pests chomp some in the field and vittles inevitably spoil on their way to the store, but picky grocers and shoppers waste plenty as well. Here’s a rough breakdown of when and why we squander our sustenance. 1 Withered on the vine Farmers frequently seed more crops than they think they’ll sell to backstop against leaf-eating pests, catastrophic weather, and sudden spikes in demand. If growers don’t need the excess, they’ll let it sit and rot in the fields rather than pay to harvest it. Producers don’t weigh their unused acres, so we can…

BACK IN 2016, THE IMPOSSIBLE Burger claimed the title of “the veggie burger that bleeds.” Its secret: a lab-grown version of the heme molecule, which occurs naturally in meat and contains much-needed iron. It gave the grub its meaty taste and pinkish hue. The company bonded the heme to a wheat-based protein, whose molecular properties meant that the gen-one concoction worked only in the form of a patty; you couldn’t crumble it or give it any other shape. Also, it wasn’t gluten-free. For version 2.0, which is coming to everything from White Castles to grocery stores this year, the company swapped its protein source from wheat to soy. The change makes the chow friendly to those with gluten sensitivities, and gives it a structure that lets it crumble (read: Impossible…

WE’RE PRETTY QUICK TO SEND BROKEN HOUSEHOLD STUFF TO THE LANDFILL in favor of something new and shiny. Simple repairs and basic maintenance, however, can make your items last longer—and avoid creating more waste. But even a simple task like securing a wobbly chair can turn into a multihour ordeal without the right fix-it kit. Step into your snappiest overalls, then grab these implements and demolish your to-do list. 1 Measuring tape There’s not always a place to hook the end of a measuring tape to hold it straight. The coated steel blade on Stanley’s Fatmax 25-footer is stiff enough to extend up to 13 feet into the air. 2 Clamp A pistol grip on Irwin’s 12-inch clamp lets you close its jaws with one hand around what you need…

IN 1798, ENGLISH CLERGYMAN THOMAS Malthus published a slim but provocative volume titled An Essay on the Principle of Population. The book went viral (by 18th-century standards) for its stunning conclusion that “the power of population is indefinitely greater than the power in the earth to produce subsistence for man.” If people kept procreating, Malthus argued, we’d run out of planet. Two centuries later, scientists are still grappling with that possibility. For most of history, our numbers have been negligible. If Odysseus really did sail the wine-dark sea in the 12th century B.C., he was one of only around 50 million people alive at the time. As Muhammad composed the Quran some 1,800 years later, the population was roughly 200 million. But the Industrial Revolution pushed that crawl into a…

JUST OFF THE COAST OF THE Keys, wind-driven swells toss our little boat like a bath toy. Nearly 30 feet below, in the blue murk, divers tend their plot: a sparse patch of sea-floor 10 meters square. One swimmer hovers over a brain coral the size of a fish bowl, studying its corduroy surface as she readies a syringe in one hand. She dispenses a droplet of white putty and dabs it onto the edge of the colony. Back at the surface, Karen Neely, a Nova Southeastern University marine biologist with the easy manner (and tan) of someone who spends her professional life on the water, scans survey sheets marked with terse scribbles of observation. Coral reefs are bleaching around the globe, but Neely and her collaborators are grappling with…

The 2017-18 season was set to be a bounce-back year for Florida oranges. We’d had almost a decade of decline due to a bacterial infection called citrus greening, which clogs the veins of the plant and stops nutrients from reaching the fruit. But tweaks to irrigation and nutrition seemed to be yielding a healthier crop. Then, Hurricane Irma took the most destructive path possible: through the center of the state, the heart of the industry. My family’s been growing since 1920, and it was by far one of our worst years. Greening stresses trees. They seem to react by producing way more fruit than they’re capable of, and wind up ditching part of the payload about a month before harvest. In the end, we’ll get about half of what healthy…

Amid the faded photographs and yellowed clippings in the attic box that holds the sum record of my ancestors, one item stands out. It’s a short article from The Wichita Weekly Eagle, boldly headlined: “Sam Genoway’s Farm Tractor.” Sam, a distant cousin of mine, was apparently so happy to see his name in the paper that he didn’t bother to make sure the writer got the spelling correct. But the story wasn’t really about him anyway. As the title would suggest, the focus was Sam’s tractor. “People have found out how many different kinds of work he can do,” his wife, Carrie Mae, told the reporter, “and they come from miles around.” It was May 1917. America had declared war on Germany, and President Woodrow Wilson classified wheat, what Sam…

WALK THROUGH BALTIMORE’S NEIGHBORHOODS, AND LOOK UP. THE FAN-SHAPED GINKGO LEAVES AND RUBY-RED PEARLS DANGLING FROM CHERRY BRANCHES ARE THE LITERAL FRUITS OF HOW GENE DESANTIS HAS SPENT THE PREDOMINANT PART OF HIS LIFE. ON SATURDAYS, THE SLIGHT, CAP-WEARING 57-year-old plants trees. By his count, 15,223 of them over the past 40 years. For DeSantis, an MVP to local greening outfits, the routine began as a form of therapy. The Baltimore native spent some of his childhood in Los Angeles, with an alcoholic stepfather and drug-addicted mother. On the nights his stepfather’s drunkenness turned violent, the young DeSantis climbed trees in the yard to find peace. “Trees became my friends,” he says. “You could say I kind of grew up there.” One night in 1976, his stepfather shot and killed…

IN THE LATE WINTER SUN, YELLOWSTONE NATIONAL PARK’S BLANKET OF SNOW IS BLINDINGLY WHITE. THE GREAT SHAGGY BEASTS—BISON, IN THEIR THICK, BURNISHED WINTER COATS—THRIVE IN THE GLARE. A FEW YARDS FROM WHERE I STAND ON THE ROAD, a small group is gathered, sweeping their upturned horns from side to side, grunting softly as they plow away the snow to graze. I’m transfixed, so it takes a minute to notice the hundred or so more scattered in the valley ahead of me. Across the steep rise of the Gallatin Range, bushes dotting the ridge come into focus; each, I realize, is a buffalo, lumbering out of the mountains toward lower elevation. Each winter, Yellowstone’s bison move from the high country in groups of a few dozen, seeking better feeding grounds. The…