Discover Magazine 2017-07-08

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JULY/ AUGUST 2017

CATCHING A CRIMINAL

EVOLUTION

AUTISM ANCIENT DNA

SURVIVING SPACE

THE PERFECT BATTERY

HOW WE DECIDE

MARIJUANA ALIEN CONTACT

DARK UNIVERSE

THE FUTURE OF FOOD

...AND MUCH MORE!

The Apocryphal Jesus

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BY AU

LECTURE TITLES

31

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THE OHIO STATE UNIVERSITY

T I ME O F

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Taught by Professor David Brakke

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1.

The Influence of Apocrypha

2.

Jesus and Mary in the Proto-Gospel of James

3.

Young Jesus in the Infancy Gospel of Thomas

4.

Joseph and the Magi in the Apocrypha

5.

The Apocrypha and the Cult of Mary

6.

Lost Gospels and Fragments

7.

Sayings of Jesus from the Gospel of Thomas

8.

Jesus’s Statements beyond the Gospels

9.

Conversations with the Living Jesus

10. The Gospel of Judas’s Gnostic Vision 11. The Gospel of Peter and the Talking Cross 12. The Apocrypha and Pilate’s Sanctification 13. Dialogues with the Risen Jesus 14. Hope and Adventure in the Acts of John 15. Social Disruption in the Acts of Paul 16. Thecla: Independent Woman of the Apocrypha 17. Miracles and Magic in the Acts of Peter 18. Peter versus Paul in the Pseudo-Clementines 19. The Acts of Thomas and the Mission to India 20. Spiritual Love in the Acts of Andrew

What Does the New Testament Leave Out? The canonical Bible is one of the most influential books in all of Western history, but you might be surprised to find out how many gaps and contradictions the New Testament contains. Much of what we know about Jesus today actually comes from apocryphal gospels, letters, and more. The Apocryphal Jesus is your chance to fill in the gaps and discover a new perspective on Jesus and his world. Over 24 revealing lectures, Professor David Brakke of The Ohio State University takes you on a tour of this world and surveys the major apocryphal works that have survived. Here you will examine views of the Virgin Mary through the ProtoGospel of James, survey the Gnostic vision presented in the Gospel of Judas, encounter a radically different view of Jesus’ teaching in the Gospel of Thomas, and more. By exploring the stories and ideas that shaped the foundations of Christian thought—and continue to influence Christianity today—The Apocryphal Jesus is a must-have course for skeptics, seekers, and believers interested in the foundations of Christianity.

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Contents

Website access code: DSD1708 Enter this code at: www.DiscoverMagazine.com/code to gain access to exclusive subscriber content.

JULY/AUGUST 2017 VOL. 38, NO. 6

EVERYTHING

WORTH

KNOWING

ROEN KELLY/DISCOVER

Starting on page 28.

SPECIAL FEATURE SECTION Nowadays, it’s common to experience information overload on a topic, only to discover that a lot of that info wasn’t based on rigorous research. You won’t find that here. This issue offers legit science on 16 topics. Learn the essentials about Auroras, How We Decide, the Future of Food, Catching a Criminal, When We Left Water (Evolution), Virtual Reality, Asteroids, Ancient DNA, Marijuana, Alien Contact, Autism Spectrum Disorder, Ice, Surviving Space, Yeast, the Dark Universe and the Perfect Battery.

Earth’s magnetic poles create light shows in the sky. Read more about auroras on page 30.

July/August 2017 DISCOVER

3

Contents COLUMNS & DEPARTMENTS 6

EDITOR’S NOTE

Unspooling the Essential Code DNA threads through all the stories in our special feature section: Everything Worth Knowing.

9 THE CRUX Lab-created meat is taste-worthy for many people; brain function continues in a person declared clinically dead; cutting carbon dioxide levels in the atmosphere may require more than lowering emissions; dive into our favorite science summer reads; and more.

18 VITAL SIGNS Under Pressure A patient with pain complaints but no sign of a serious condition is actually a ticking time bomb with a deadly malady. BY CHRISTOPHER TEDESCHI

Read about the James Webb and NASA’s next telescope on page 83.

NASA has plans for a bigger and more powerful space observatory to continue the quest to find other pale blue dots in the universe. BY KOREY HAYNES

94 PROGNOSIS The Body Electric

22 NOTES FROM EARTH The Desert’s Living Skin A blanket of tiny plants and organisms keeps drylands healthy. But what happens when they disappear? BY KATHERINE MAST

A scientist’s innovative work harnesses the body’s movements to improve medical devices. BY STEPHEN ORNES

98 20 THINGS YOU DIDN’T KNOW ABOUT …

Meet the NextGeneration Space Telescope

Powered by magazine

Even with the James Webb Space Telescope set to launch next year,

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Yoga The discipline practiced by most people today has little in common with the ancient tradition, but that doesn’t mean you should toss out your mat and leggings. BY GEMMA TARLACH

ON THE COVER The Desert’s Secret Life p.22 Tomorrow’s Telescope p.83 Everything Worth Knowing p.28 Cover illustration by Nata-Lia/Shutterstock

NASA/DESIREE STOVER

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Discover SCIENCE FOR THE CURIOUS

Editor's Note

®

BECKY LANG Editor In Chief DAN BISHOP Design Director

Unspooling the Essential Code It’s in my DNA — it’s just how I’m wound. How many times has that phrase run through your head? My hunch is more than a few. It’s an apt explanation for how you think, operate, get through life. It’s that essential nature of DNA that’s the thread of this special issue, Everything Worth Knowing. We’ve taken over the magazine’s feature section with 16 stories that give you the basics as well as the new research on a range of scientific disciplines. DNA is coursing through them all, from the latest forensic science on how to catch a criminal to the ingredients needed for surviving and prospering on Mars. DNA is crucial to figuring out our future food supply, with a planet that will be home to more than 9 billion by 2050. The intrinsic code of DNA sheds light on who strode our planet before us, as anthropologists consistently learn more from ancient genomes. And those keys to life lurk as astronomers search for any ping of alien life in our solar system. I’d argue that DNA is even part of virtual reality. We take you through the basics of this alternate world, and how it can transcend normal life. It’s a trip that goes beyond our DNA. And, as it happens, a pretty eye-opening way to unwind.

EDITORIAL KATHI KUBE Managing Editor GEMMA TARLACH Senior Editor BILL ANDREWS Senior Associate Editor MARK BARNA Associate Editor ERIC BETZ Associate Editor LACY SCHLEY Assistant Editor DAVE LEE Copy Editor ELISA R. NECKAR Copy Editor AMY KLINKHAMMER Editorial Assistant Contributing Editors

TIM FOLGER, JONATHON KEATS, LINDA MARSA, KENNETH MILLER, STEVE NADIS, ADAM PIORE, COREY S. POWELL, JULIE REHMEYER, STEVE VOLK, PAMELA WEINTRAUB, JEFF WHEELWRIGHT, DARLENE CAVALIER (SPECIAL PROJECTS)

ART ERNIE MASTROIANNI Photo Editor ALISON MACKEY Associate Art Director

DISCOVERMAGAZINE.COM CARL ENGELKING Web Editor NATHANIEL SCHARPING Web Staff Writer Bloggers

MEREDITH CARPENTER, LILLIAN FRITZ-LAYLIN, JEREMY HSU, REBECCA KRESTON, JEFFREY MARLOW, NEUROSKEPTIC, ELIZABETH PRESTON, SCISTARTER, CHRISTIE WILCOX, TOM YULSMAN

ADVERTISING STEVE MENI Advertising Sales Manager 888 558 1544 [email protected]

Rummel Media Connections KRISTI RUMMEL Consulting and Media Sales 608 435 6220 [email protected]

MELANIE DECARLI Marketing Architect BOB RATTNER Research DARYL PAGEL Advertising Services

KALMBACH PUBLISHING CO. DANIEL R. LANCE Senior V.P., Sales & Marketing STEPHEN C. GEORGE Vice President, Content JAMES R. MCCANN Vice President, Finance NICOLE MCGUIRE Vice President, Consumer Marketing JAMES SCHWEDER Vice President, Technology ANN E. SMITH Corporate Advertising Director MAUREEN M. SCHIMMEL Corporate Art Director KIM REDMOND Single Copy Specialist MIKE SOLIDAY Art and Production Manager

SUBSCRIPTIONS In the U.S., $29.95 for one year; in Canada, $39.95 for one year (U.S. funds only), includes GST, BN 12271 3209RT; other foreign countries, $44.95 for one year (U.S. funds only).

Becky Lang Feel free to send comments and questions to [email protected]

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THE CRUX T H E L ATEST S CI E N C E N E WS A N D N O T ES

FUSION FRAMEWORK With his robot assistant, a technician works on the world’s largest fusion research device of its kind at the Max Planck Institute for Plasma Physics in Greifswald, Germany. The experimental equipment, dubbed Wendelstein 7-X, will test the feasibility of stellar nuclear fusion — in which nuclei bind together and release energy — as a clean energy source. It uses magnetic fields from 70 supercooled magnets to contain just a few thousandths of a gram of superheated hydrogen plasma. The plasma must sustain extreme temperatures — about 100 million degrees Celsius, or 180 million degrees Fahrenheit — before fusion can happen. Wendelstein 7-X took more than 10 years to build and cost over $1 billion.  ERNIE MASTROIANNI; PHOTO BY STEFAN SAUER/DPA/ALAMY

July/August 2017 DISCOVER

9

THE CRUX

NASA’s Orbiting Carbon Observatory-2 captures carbon dioxide as it changes with Earth’s seasons. This visualization shows increased carbon dioxide in red. Decreased levels are blue.

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BIG IDEA

What Carbon Really Costs

NASA’S SCIENTIFIC VISUALIZATION STUDIO

Even if we curb emissions, wrangling greenhouse gases will mean a price tag of trillions. ATOP EARTH’S LARGEST active volcano, an alarm bell has tolled unheeded for six decades. In 1958, Scripps Institution climatologist Charles Keeling began making precise measurements of atmospheric carbon dioxide concentrations at Mauna Loa Observatory. Back then, Earth’s atmosphere clocked roughly 310 parts per million (ppm) of carbon dioxide. It took just a year for Keeling to spot a now-familiar upward trend. “You can think of it as taking planetary vital signs,” says Ralph Keeling, who continues his father’s work at Scripps today. The news isn’t good. In April, carbon dioxide hit 410 ppm, a 50 percent increase from preIndustrial Revolution levels. And it’s been increasing roughly 3 ppm per year, a record rate. Last year, 175 countries agreed to reduce emissions via the Paris Agreement, which — optimistically — could hold global temperatures to an increase of 1.5 degrees Celsius since pre-industrial levels. “We are almost there already,” says glaciologist Eric Rignot of the University of California, Irvine. “I think at some point, people will realize we’ve already passed it.” Our current emissions trajectory locks Earth into a carbon dioxide level of at least 450 ppm, Ralph Keeling says. And burning fossil fuels at the same increasing rates through 2050 would drive those levels to their highest point in 50 million years, according to an

April study in Nature Communications. Add a few more centuries of similar emissions, and carbon dioxide levels rise to those not seen in 420 million years, causing unprecedented sea level rise. Keeling doesn’t think it’ll come to that. New efficiency standards and cleaner energy are already reducing emissions in the U.S. and other countries. If such efforts register at Mauna Loa, it could show humans still have some control. “It’s been an alarm bell so far — the curve,” Keeling says. “But if we start to take positive steps, it can become a sign of progress and hope.” However, new research shows that reducing emissions isn’t a complete fix. “If you just stop emitting cold turkey, the temperature drops a little, but it doesn’t drop too much,” says MIT atmospheric scientist Susan Solomon. “The temperature stays almost as hot for 700 years.” That’s because the carbon dioxide remains trapped in the atmosphere — much of it lingers a millennium later — pumping more and more energy into the ocean. So temperatures stabilize, but the seas keep rising. This means humans actually have to remove greenhouse gases to reach levels scientists consider safe, roughly 350 ppm. And even short-lived greenhouses gases — methane

lasts about a decade — will still cause sea levels to rise for centuries. The reason is fairly simple. Greenhouse gases trap extra heat in our atmosphere, and oceans suck most of it up. As the warmer water expands, it causes sea levels to rise. And like a hot bath, the ocean must radiate its heat back out — through the atmosphere and into space — for it to cool. Former NASA scientist James Hansen, now at Columbia University, helped launch climate change into the public sphere with his 1988 testimony before Congress. “[A level of] 450 ppm would guarantee disaster,” Hansen says now. “If you leave it in place long enough, it would guarantee that you do lose the coastal cities.” And in a recent study in Earth System Dynamics Discussion, Hansen’s team writes that to reach 350 ppm, humans must spend the next century extracting billions of tons of carbon dioxide from the atmosphere. They calculated a range of options to reach that threshold, putting the final price tag between $100 billion and over $1 trillion — each year, for roughly 80 years. They found that returning Earth to 350 ppm by 2100 requires planting trees on an epic scale, as well as substantial investments to boost soil fertility so it holds more carbon. We’d also need large-scale tech to remove the gas, something not currently feasible. Others are exploring alternative approaches. A Harvard University program is spending $20 million to launch particles into the stratosphere to test a kind of solar shield. Some scientists fear that even talking about such geoengineering will embolden people to keep polluting. But that hasn’t stopped the discussion. “All the pollution we put in the air, we’re going to have to take it back,” Rignot says.  ERIC BETZ

In April, carbon dioxide hit 410 ppm, a 50 percent increase from preIndustrial Revolution levels.

July/August 2017 DISCOVER

11

THE CRUX

TRENDING BY LACY SCHLEY

Who Will Give Lab-Grown Meat a Chance? A recent study surveyed nearly 700 people to suss out their attitudes toward meat created in a lab, so-called in vitro meat (IVM). Here's what researchers found:

65%

Degrees of Separation From life after death to life under the seabed.

How much longer it took heart attack and cardiac arrest victims to get to the hospital via ambulance on mornings when their city was hosting a marathon.

10%

1%

No response

Much more

15%

11%

Somewhat more

Much less

34%

29%

No more, no less

Somewhat less

WHAT KIND OF IVM ARE PEOPLE WILLING TO TRY?*

45%

63%

69%

Poultry

Pork

Fish

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5.3%

3.1%

Horse

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*Note: Participants who indicated no interest in trying IVM did not answer these questions. Source: “Attitudes to in vitro meat: A survey of potential consumers in the United States,” PLOS One, 2017

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5 MILLION

The rate at which some mosquitoes can beat their wings; researchers have just figured out the unique wing movements involved.

20%

4.4

The approximate speed at which scientists observed a supermassive black hole, roughly 8 billion light-years away from Earth, hurtling through space.

800

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HOW MUCH ARE PEOPLE WILLING TO PAY FOR IVM COMPARED WITH TRADITIONAL MEAT?*

MPH

would likely eat IVM regularly

The minimal humidity level — typical of most arid climates — that a new solar-powered device needs to harvest water from the air.

The depth (a little over 6 miles) below the seabed at which life could exist. Mud samples from underwater volcanoes near the Mariana Trench, the deepest part of the ocean floor, revealed chemicals usually produced by living organisms. But the jury’s still out on whether anything is actually living down there.

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BUNDLED UP Within a brain nerve cell, or neuron, the axon is the long, wiry extension that carries electrical impulses to a neighboring neuron. Just like household wires, these biological versions (shown in orange) need insulation to function properly; without it, central nervous system disorders can develop. A fatty substance called myelin (shown in yellow) serves this important purpose. In this view, magnified 10,000 times, myelin encases the axons of a mouse’s spinal nerve root, part of the spinal cord that communicates with the brain. Thomas Deerinck and Mark Ellisman of the National Center for Microscopy and Imaging Research at University of California, San Diego, took this picture while researching cellular architecture.  ERNIE MASTROIANNI; PHOTO BY THOMAS DEERINCK AND MARK ELLISMAN, NCMIR

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SHARK By Brian Skerry

STRANGE CONTAGION:

Forget the suspense and gore of Jaws or the hyperbolic titillation of many television docudramas. Photographer Skerry captures the beauty and diversity of these “lords of the sea.” Each chapter, penned by different writers, focuses on a different species and pairs plenty of science with Skerry’s images.

Silver jacks swim beneath a great white shark.

In side the Surprising Scien ce of Infectious Behaviors a nd Viral Emotions a nd What They Tell Us About Ourselves

CAESAR’S LAST BREATH:

THE ENDS OF THE WORLD:

ATOMIC ADVENTURES:

Decoding the Secrets of the Air Arou nd Us

Volcanic Apocalypses, Lethal Oceans, and Our Quest to Understand Earth’s Past Mass Extinctions

Secret Isla nds, Forgotten N-Rays, a nd Isotopic Murder — A Journey in to the Wild World of Nuclear Science

By Sam Kean With sly wit and boyish wonder, Kean’s vignettes about key events in the understanding of air include numerous entertaining detours, such as the work of “William McGonagall, probably the worst poet who ever lived,” and Le Pétomane, a flatulence artist.

By Peter Brannen As a rising tide of research suggests we’re at the start of a sixth mass extinction event — the first caused by human activity — science writer Brannen walks us through the previous die-offs, gleaning clues about what may be around the corner for us.

By James Mahaffey Characters major and minor in the story of nuclear science come alive in Mahaffey’s lively, accessible retelling of some of the field’s more obscure (and sometimes ignominious) moments.

UNSOLVED! The History and Mystery of the World’s Greatest Ciphers from Ancient Egypt to Online Secret Societies By Craig Bauer The Da Vinci Code has nothing on this exhaustive collection of cryptographs and codes — because these are real. From a still-indecipherable 14th-century manuscript to spy communications to the infamous coded taunts of the Zodiac Killer, Bauer shows how experts try to crack the case.

After moving to Silicon Valley, science writer and new father Kravetz investigates a rash of suicides by teenagers in his community. He juxtaposes his personal journey into parenthood with the worries and rumors in the neighborhood about what led to the deaths. Using his background in psychology, Kravetz probes how humans’ inherent mimicry and social nature can create dangerously contagious behavior. His gripping narrative has the tension of a thriller, but the stories he shares are tragically real.  REVIEWS BY GEMMA TARLACH

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Under Pressure A middle-aged man has common complaints of chest and stomach pain, but the final diagnosis is anything but typical. BY CHRISTOPHER TEDESCHI

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Scott arrived in the emergency room by ambulance around 3 p.m., complaining of chest and abdominal pain. The medics described him as pale and sweaty, and said he may have passed out for a few minutes when the pain began. A seasoned triage nurse’s immediate reaction: “He doesn’t look right.” That’s the last thing an ER physician wants to hear when a patient arrives. Scott was a mostly healthy 48-year-old with untreated high blood pressure. His initial cardiogram showed possible signs of reduced cardiac blood flow and maybe even a heart attack. But after negative cardiac blood tests and improvement in Scott’s symptoms, the team agreed that nothing was immediately life threatening. Healthy middle-aged men complain of chest pain and upper abdominal pain for dozens of reasons, from indigestion to something serious like a heart attack. Best guesses on Scott’s chest pain: high blood pressure, a stomach ulcer, a panic attack. The plan was to admit him to the hospital for observation and more cardiac testing. We’d keep him in the ER until a hospital room became available. At 8 p.m., Scott looked comfortable when our team huddled around his stretcher, squeezed next to other patients on a crowded Friday night. He was chatting with his family as they drank apple juice from plastic cups. He was still with his family a couple of hours later, but his arms were

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crossed on his belly, and he was slowly rocking back and forth. He was a little sweaty. And he had that pale look the nurse had noticed earlier.

SEEKING ANSWERS Scott’s work-up revealed no objective signs of trouble. No fever, no increased heart rate, nothing scary on the heart monitor. I swung around to his stretcher to do a closer exam. He told me his belly hurt, and he felt mild pain when I pressed on the right upper part of his abdomen. Maybe this wasn’t a cardiac problem after all. Scott might have painful gallstones or, at worst, cholecystitis: inflammation of the gallbladder that can be excruciatingly painful, comes in waves and causes some people to pass out. A quick ultrasound could detect gallstones or

kidney stones, even internal bleeding. I decided to take a peek. For many of us who trained in the past 15 to 20 years, the ultrasound machine is a second stethoscope. The technology first made its way into the ER via the trauma bay as a tool for a FAST (focused assessment with sonography in trauma) scan. Scott’s FAST was negative. I moved the ultrasound probe up to his gallbladder to look for gallstones. Nothing. I like to think I am smart enough to reason my way to a diagnosis, even in patients with vague or confusing complaints. But something didn’t make sense. His pain was severe and unexplained. While the odds favored something harmless, his symptoms suggested it could be far more serious. Training in emergency medicine means you are constantly asking yourself, “What is going to kill this patient today?” That’s different from what most students are taught in medical school, which is to ask, “What is most likely?” In the ER’s intentionally paranoid world, headache means brain bleed until proven otherwise, chest pain means heart attack, and abdominal pain means . . . I slid the probe to the middle of Scott’s belly, pressed a little harder to get intestines out of the way and found his aorta, the main artery that carries blood under high pressure from the heart’s left ventricle to the abdomen, pelvis and lower extremities. The thick-walled aorta is usually about 2 centimeters in diameter. It pulsates on the ultrasound screen when pressure is applied. The diameter looked right. But as I rotated my wrist 90 degrees so that the ultrasound could show me a picture of the aorta lengthwise, the image stopped me cold. The information that made everything else fall into place pulsed along with the patient’s

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heartbeat on the screen. A thin but unmistakable bright line bisected the vessel, flapping back and forth in the middle of the blood-flow area. I was watching, in real time, an acute aortic dissection. Scott’s aorta was shredding itself in two.

A DEADLY FIND In an aortic dissection, the flap is the innermost of the aorta’s three layers, which — because of high blood pressure, atherosclerosis or an inherited disease — tears loose from the surrounding outer portion. The tear allows high-pressure blood to flow between the layers, which loosens them. The dissection splits the aorta along a path that can travel from the aortic valve through the chest and abdomen. Dissection is as rare as it is deadly.

20

Blood enters lining tear of aorta Dissection

Each year, there are roughly three to four new cases of aortic dissection out of 100,000 people in the general population. That number may be an underestimate, however, as the condition is often missed even after multiple medical visits, or because patients die before evaluation. It’s a hard one to diagnose. In 1996,

Jonathan Larson, who posthumously won a Pulitzer Prize for drama for the landmark musical Rent, visited two New York City hospital emergency departments over three days, complaining of severe chest pain and shortness of breath. A New York State Health Department investigation found that Larson was twice discharged with diagnoses of “food poisoning” and “viral syndrome,” according to the department’s report. Roughly 24 hours after leaving the ER, Larson, age 35, was found dead on his apartment floor. His autopsy revealed an aortic dissection. For an emergency physician, diagnosing a condition so ominous is a little unnerving. Suddenly you’ve identified the sickest patient in the ER. The patient’s survival now depends on dozens of health care providers, a specialized operating

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Vital Signs

room and an intensive care unit, if the patient is lucky. In an acute dissection, the mortality rate can increase by as much as 1 percent every hour after symptoms appear. It was now shortly before midnight, nine hours since Scott arrived. A thought filled my head: This guy is going to drop dead in front of us unless we do something right now.

SKIRTING CATASTROPHE An emergency CT scan revealed a dissection that started at the ascending aorta, near the origin of the coronary arteries, which supply blood to the heart. It extended over the aortic arch, down the descending aorta through the abdomen and into the smaller arteries that supplied blood to the brain, intestines and kidneys. This was a huge dissection, encompassing

the aorta’s entire course and several smaller branches. Any further interruption of blood flow along that path could deprive Scott’s bowels, liver or brain of oxygen. Before sunrise, cardiac surgeons replaced most of his ascending aorta and arch with a synthetic graft, essentially sealing off the leak. A new aortic valve completed the repair, since Scott’s own valve was too damaged to function properly after the dissection. Scott spent a few days in the cardiothoracic intensive care unit, fighting through a minor infection and the pain of open-heart surgery. He left the hospital a week later with prescriptions for several medications, including four different drugs to control hypertension. Though the exact cause of his dissection remains unknown, it was likely due to

untreated high blood pressure and possibly an inherited component yet to be diagnosed. As an emergency physician, I often wonder how close I’ve come to catastrophe by missing a diagnosis. On a busy night, the emergency team risks the temptation to overlook the patient with seemingly unrelated symptoms who isn’t in obvious distress. Equally dangerous conditions can be subtle and elusive, becoming apparent only after time, thought and re-evaluation. And then there’s that final lesson: Always respect the look. D Christopher Tedeschi is an emergency physician at New York-Presbyterian Hospital and assistant professor of medicine at Columbia University Medical Center. The cases described in Vital Signs are real, but names and some details have been changed. July/August 2017 DISCOVER

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Notes From Earth

The Desert’s Living Skin Communities of tiny plants and organisms protect arid landscapes. Now their survival is threatened. BY KATHERINE MAST

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On a cool September morning, a caravan of international scientists rumbles past the iconic formations of Canyonlands National Park in Utah. Over the eons, wind and water have carved this landscape into a maze of stunning red sandstone arches and spires. The researchers marvel at the formations, so different from their own backyards — places as distant as China, Niger, Australia and Spain. But when they pull into the parking lot for a short hike to Pothole Point, their attention goes straight toward their feet. A thick, bumpy film covers large patches of the giant sandstone slabs. The patches resemble burnt soil, as if a fire left behind only these charred remains. Up close, the spots mimic the Canyonlands’ topography on a tiny scale: Centimeter-tall towers rise above a network of valleys. These dark, crusty soils span the arid Colorado Plateau in the Four Corners region.

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Here, the ground is alive. Biological soil crusts, or biocrusts, are crammed with communities of tiny photosynthetic organisms and other life-forms. Biocrusts in some parts of the world are mostly cyanobacteria, one of the oldest microorganisms on Earth. Other biocrust communities, like these on the Colorado Plateau, include mosses, lichens and fungi. The first scientists to study them called these living crusts “cryptogamic” — Greek for “hidden marriage” — because their inner workings were still mysterious. And while they might seem secretive, biocrusts are critical to healthy drylands around the world. But now, ecologists are worried that a changing climate will put them in jeopardy.

DON’T BUST THE CRUST Drylands cover nearly half of the world’s landmass and sustain more than 2 billion people. Biocrusts are important components of these arid

ecosystems. When it does rain — and in the desert Southwest, summer rains come in monsoonal downpours — those peaks and valleys on the soil surface help retain the water. That both improves water absorption and reduces erosion. Biocrusts also add nitrogen and carbon to the nutrient-poor soil, a critical service for plants. And, perhaps most importantly, the cyanobacteria’s sticky slime and the root-like filaments of the mosses help bind soil to earth. “The wind can whip through this ecosystem, almost knock you down, and this crust is going to stay 100 percent solid,” says Sasha Reed, a research ecologist with the U.S. Geological Survey (USGS) Southwest Biological Science Center in Moab, Utah. Despite their resilience to wind, biocrusts crack under pressure. When hikers, bikers and vehicles stray from established paths, or livestock roam, they can leave a trail of bare earth where crusts used to live. Then, when the wind blows, those areas kick up sand. “That dust is going to enter the atmosphere,” says Reed. “It’s fertility leaving. It’s going to be deposited

FROM LEFT: BILL BOWMAN/UNIVERSITY OF COLORADO; JEFF MITTON/UNIVERSITY OF COLORADO

Desert locales like Utah’s Canyonlands (left) rely on biocrusts — lichens, mosses, fungi (below) — which take years to grow.

M

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Notes From Earth

Scientists, like Jayne Belnap (left) and Sasha Reed (right) from USGS, use test plots to explore how biocrusts handle climate change.

CLIMATE MANIPULATION Some 12 miles northeast of Moab, a thin electric fence partitions a mesa overlooking the Colorado River. Inside are 20 experimental plots where USGS researchers are simulating future climates to learn how biocrusts might respond. Infrared lamps overhang some sections, keeping them consistently 7 degrees Fahrenheit warmer than the control plots. Other plots get regular doses of misted water. Some receive both. This allows scientists to look at the individual factors of warming and precipitation, and also study how those two factors might interact. “We know the temperatures are going to increase,” says Jayne Belnap, a USGS ecologist and biocrust research pioneer. “Precipitation, that’s a lot more variable, and people don’t really know what’s going to happen.” The future could bring light, regular rains. Or we might see more frequent heavy

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rainfalls. Or perhaps less frequent, but even larger, storms. Reed stands by a plot hit with both heat lamps and light, regular water treatments. The ground looks trampled. It’s surprising that just a little water could cause this kind of damage. Reed and Belnap think the water gives the crusts just enough moisture to rev up metabolism, but not enough to replace the energy they’ve used, especially as heat speeds up evaporation. What’s troubling is how quickly the warmed and watered crusts disappeared — they were barren in less than a year. “You can tell right away which ones got watered,” says Belnap. “Everything used to look like that over there,” she says, pointing to a distant control plot with visible, thick crusts. “It was stunning and disappointing and somewhat gut-wrenching,” says USGS researcher Scott Ferrenberg, the lead author on a paper analyzing data from these experiments.

JENNIFER LAVISTA/USGS (3)

elsewhere.” And when dust from Utah settles on Colorado’s snow-packed Rocky Mountains, those dark-colored sand particles speed up spring snowmelt by absorbing more solar energy. Because of the limited water of desert ecosystems and other factors, it can take a long time for these disturbed areas to recover. In the best-case scenario, cyanobacteria will recolonize the soil in five years or so. It takes another 20 years for a community rich with lichens and mosses to establish. In very dry places, like California’s Death Valley, scientists say full recovery takes up to 250 years. And alarmingly, recent studies show climate change can wipe out biocrusts just as surely as physical disturbance.

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Other researchers, like Fernando Maestre, a professor at Rey Juan Carlos University in Spain, are doing similar experiments in other parts of the world. Nearly 75 percent of Spain is classified as drylands. “Climate models predict really, really high warming for Spain, particularly during the summer. And summer in Spain is already really hot,” he says. “We need to know what is going to happen before we can think of ways of mitigating it.” Maestre’s experiments are showing results similar to those from USGS.

ASSISTED MIGRATION The future doesn’t look good for biocrust communities, and thus for the stability of desert soils, as we continue to careen toward a warmer climate. But researchers still hold out hope. “We’re trying to turn to a more optimistic phase to see if there’s some way we could help these communities to return,” says Ferrenberg. Several universities are trying to culture biocrust organisms in greenhouses and reintroduce them to damaged landscapes. Results are mixed so far. In China, government scientists sprayed a cyanobacteria-loaded slurry over growing sand dunes and stopped their advance. But recent experiments in New Mexico and Utah have been hit-or-miss, and it’s not clear why. “The jury’s out in terms of restoration and how much success we might have in the face of climate change,” says Ferrenberg. Scientists are also exploring assisted migration, a controversial topic in ecology where species are moved from a place they currently thrive in to places they might survive as the globe warms. The Moab USGS team just began a new “common garden” experiment to see which crust communities might fare the best in a warmer Utah. They gathered crust samples from different ecosystems across the Southwest and grew them in a greenhouse at Northern Arizona University. Early this year, the team spread those samples in adjacent Utah plots. Similar to climate manipulation plots near the Colorado River, half of these plots are warmed with infrared lamps to simulate the future. “Right now, the plots look like sand with confetti colors. So, we’re waiting to see how those communities take shape over time,” says Reed. If the native crusts can’t withstand the expected warming, maybe the crusts already adapted to hotter deserts could. In the end, perhaps preserving the biocrust’s ecosystem function is more important than preserving species native to the Colorado Plateau. D

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SPECIAL SECTION

EVERYTHING

WORTH

KNOWING

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p. 30

Auroras

p. 34

How We Decide

p. 38

The Future of Food

p. 40

Catching a Criminal

p. 44

When We Left Water

p. 48

Virtual Reality

p. 50

Asteroids

p. 52

Ancient DNA

p. 56

Marijuana

p. 58

Alien Contact

p. 62

Autism Spectrum Disorder

p. 66

Ice

p. 70

Surviving Space

p. 74

Yeast

p. 76

The Dark Universe

p. 78

The Perfect Battery

DISCOVERMAGAZINE.COM

We get it. You’re bombarded with new information every single day — heck, every hour. If only someone were around who could sort through it all and give you the freshest, most legit stuff in science, a knowledgeable guide who could plow through the thousands of scientific papers published each week and just tell you what you need to know, and what you’d like to know. With our latest collection of Everything Worth Knowing, we aim to catch your curiosity with the story of how our distant ancestors left the oceans, help you learn the basics of talking to E.T. and make sense of the systems that affect how we make decisions — among other things. Consider this special section your knowledge curator, with its blend of shorter and longer takes on everything from autism to yeast. Whether you revisit favorite subjects or discover something new, you’ll walk away knowing more. Feel free to share your thoughts with us at [email protected]. — THE EDITORS

KELLIE JAEGER/DISCOVER

July/August 2017 DISCOVER

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EVERYTHING

Auroras

KNOWING

Colorful shape-shifters of the heavens.

WORTH

Aurora borealis, nature’s light show, puts on a display over Iceland in 2015.

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When the space weather is just right, one of nature’s grandest spectacles unfolds over Earth’s poles. Visible on clear nights, clouds of glowing green slowly morph into gyrating arcs that cover the sky — then vanish. And repeat. At times the lights appear straight overhead, falling as cosmic rain in shades of green, red and blue. It’s a phenomenon humanity has marveled at for millennia. Yet scientists are still unraveling its mystery.

J.C. CASADO-STARRYEARTH-GLORIA PROJECT

BY ERIC BETZ

Carrington Event Our modern understanding begins on Sept. 1, 1859. British astronomer Richard Carrington was tracking sunspots when a group unlike any other he’d seen appeared. It sent out two intense flashes of white light and vanished minutes later. Those bright flashes signaled that an enormous eruption — the largest geomagnetic storm in history — was heading for Earth. When it hit, the storm was so intense that sparks shocked telegraph operators

through their machines and set their paper on fire. Rare red auroras appeared as far south as Hawaii and El Salvador. Called the Carrington Event, the incident showed auroras were caused by solar activity — but half a century passed before science could explain how. Forecasters still struggle to predict this space weather, and scientists have yet to understand its subtleties. That ongoing effort is vital to protecting power grids and satellites, which are sensitive to the same power surges that have inspired awe for thousands of years.

In 1859, astronomer Richard Carrington observed strange sunspots — evidence of the largest geomagnetic storm in history — later reproduced in a sketch.

How to Get That Glow

FROM TOP: RICHARD C. CARRINGTON/THE MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY (VOL. 20, P. 13) 1860; ROEN KELLY/DISCOVER

Earth is a giant magnet with two poles. The magnetism of the sun is a little more complicated. Our star has north and south, plus a patchwork of polarities that rip holes and cause eruptions from its atmosphere. “You get a fire hose of particles coming off the sun,” says Tom Berger, director of the federal Space Weather Prediction Center in Colorado. These ejections fuel the solar wind, which races toward Earth at hundreds of miles per second. As these wind-borne particles — mostly electrons and protons — breach Earth’s atmosphere, they work just like Vegas-style neon lights. Solar particles (the electric current) stream down Earth’s magnetic field lines (the tube) and collide with molecules of nitrogen and oxygen (the gas), exciting them until they glow in various colors.

Solar wind A constant stream of solar particles.

Solar particles

Coronal mass ejection Bursts of plasma shoot off the sun, accelerating the solar wind.

Coronal hole Lower gas density and energy make an area slightly colder, and appear darker.

Prominence A large, often looping arc of gas that protrudes from the sun.

Magnetic field The solar wind pushes Earth’s magnetic field into a tadpole shape.

Special K Geomagnetic storm magnitude is measured using the Planetary K-index, after Kennziffer, a German word for “indicator.” If the index rises to 4 (on a 1-9 scale), auroras are likely and an alert is issued, a handy heads-up for power grid and satellite operators, as well as aurora chasers.

July/August 2017 DISCOVER

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EVERYTHING

WORTH

KNOWING

Auroras

Paint With All the Colors of the (Solar) Wind Earth’s atmosphere is mostly nitrogen and oxygen, but the exact concentration varies with altitude. Aurora colors do, too. Auroras happen when charged particles smash into atmospheric gases and energize them. And each gas emits a particular color as a result: Oxygen makes green light at common aurora altitudes, so that’s what we see most often.

E Electron

Oxygen atom

Excited oxygen emits radiation

O

400km

O E E

Red light

300km

O Excited oxygen emits radiation Green light

O

E

E

Nitrogen atom Excited nitrogen emits radiation

200km

N

N

E

100km Red light

AURORA BOREALIS

Magnetic field lines

Magnetic north pole

Auroral oval Auroras most often occur in this region, which creeps toward the equator during geomagnetic storms. Few auroras happen very close to the geographic and magnetic poles, though one uncommon type, the “theta aurora,” cuts across the oval’s center.

Geographic north pole

Snap, Crackle, Pop!

AURORA AUSTRALIS

Warm air Cold air

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+

+

Cold air

+

-

-

+

Geomagnetic force +

-

+

Magnetic pulse

ALL ILLUSTRATIONS: ROEN KELLY/DISCOVER

Aurora watchers have long reported hearing strange claps and crackles during intense displays, but it wasn’t until 2016 that scientists found a possible explanation: an atmospheric phenomenon called an inversion. A pocket of warm air, accumulating negatively charged particles, forms between layers of cold air full of positively charged particles without mixing. Geomagnetic disturbances force the accumulated charges to discharge, creating sparks and sounds.

Space Weather Watchers

All the Highlights 30,000 B.C. Early Europeans may have carved images of auroras into rock art panels. ~A.D. 1000 The Sami, nomadic Scandinavian reindeer herders who live north of the Arctic Circle, believe auroras were spirits of the dead. The lights are still celebrated in a type of singing called the yoik.

GOES-16 The National Oceanic and Atmospheric Administration’s latest weather spacecraft, launched in 2016, can also monitor geomagnetic storms.

DSCOVR NASA’s DSCOVR spacecraft can watch both sun and Earth, helping scientists to better understand and predict space weather.

1619 Galileo coins the term aurora borealis after the Roman goddess of dawn, Aurora, and the Greek “northern winds.” 1859 The Carrington Event’s intensity still frightens scientists today. Fortunately, ice core records show events like that rarely hit Earth. 1882-83 Danish astrophysicist Sophus Tromholt helps establish a northern lights observatory in Norway to determine aurora altitudes and shows that auroras are more likely to happen at the peak of the sun’s 11-year cycle of solar activity.

Solar Dynamics Observatory NASA’s sun-tracking spacecraft uses sound waves — similar to a medical ultrasound — to track action on the back side of the sun. Seeing what could soon face Earth lets companies prep for geomagnetic storms.

FROM TOP: NASA (4); UNIVERSITY OF COLORADO/NASA; NASA, ESA, AND J. NICHOLS (UNIVERSITY OF LEICESTER)

Alien Aurora Earth’s not alone in its regular light shows. In late December 2014, NASA’s MAVEN spacecraft watched auroras in Mars’ atmosphere (right). And Hubble caught auroras on Jupiter, too, seen in ultraviolet light (below).

Magnetic Reconnection In 2015, NASA launched the Magnetospheric Multiscale spacecraft to study the mysterious interactions between Earth and the solar wind when our planet’s magnetic field lines occasionally break and reconnect, which also affects auroral activity.

1892 German astronomer Martin Brendel takes the first aurora picture — a fuzzy image captured in northern Norway. 1909 Kristian Birkeland, a Norwegian physicist, proves that the sun’s charged particles create auroras when they hit our magnetic field. He put a magnetized sphere — a lab “Earth” — in a box and pummeled it with electrons. The sphere glowed near its poles. 1910 Another Norwegian physicist, Carl Størmer, begins photographing auroras, often simultaneously imaging the same formations from different directions. Over the next four decades he’ll take 100,000 shots, mapping the shape of auroras and determining a typical altitude of 50 to 100 miles. 1958 America’s first satellite, Explorer I, discovers the Van Allen Belts, bands of charged particles surrounding Earth born from the solar wind. 1989 A solar eruption hits Earth on March 12, sending northern lights as far south as Cuba. A power failure affects Quebec for 12 hours. 2012 A coronal mass ejection on par with the Carrington Event blasts off the sun and narrowly misses Earth.

July/August 2017 DISCOVER

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EVERYTHING

How We Decide

KNOWING

Make up your mind already!

WORTH

BY ADAM PIORE

When we’re presented with a choice, we carefully weigh the alternatives and choose the option that makes the most sense — or do we? Only recently has science begun to unravel how we really make decisions. In the face of stress or time pressure, or even seemingly unrelated cues, our assessment of situations and the choices we ultimately make can be colored by innate biases, flawed assumptions and prejudices born of personal experience. And we’re clueless about how they influence our judgments. These unconscious processes can lead us to make decisions that, in fact, don’t really make much sense at all. If you’re not convinced, go to a group of people and offer each person a dollar. Do this five times, each time asking if the individual wants to buy a $1 lottery ticket. Then offer

$5 all at once to a second group, and ask the people how many lottery tickets they would like to buy. You’d think both groups would buy the same number of tickets — after all, they got the same amount of money. Nope. Researchers at Carnegie Mellon found that the first group would consistently buy twice as many lottery tickets as the group that was given the same amount of money but only one chance to buy lottery tickets. Here’s another way to see irrational, unconscious biases in action: Change your hairstyle. This experience inspired Malcolm Gladwell to write the bestseller Blink, which looked at the science of snap judgments. After he grew his hair long, his life changed “in very small but significant ways.” He got speeding tickets, was pulled out of airport security lines, and was questioned by police in a rape case, even though the prime suspect was much taller.

The lottery and hair scenarios provide real-world examples at odds with traditional theories used to predict human behavior. These scenarios tell us that decision-making can depend on perspective and unconscious stereotypes. These kinds of biases do serve an evolutionary purpose, many other researchers have found. In some cases, making snap decisions and following your gut can be an advantage, especially in high-pressure, timesensitive situations. The hidden, unconscious processes at work when we decide are so powerful that efforts to uncover and understand them have won at least two researchers the Nobel Prize in recent years.

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DNY59/GETTY IMAGES

Unconscious processes can lead us to make decisions that, in fact, don’t really make much sense at all.

CHECKS AND BALANCES Daniel Kahneman won the 2002 Nobel Prize in Economics for his widely referenced work in the area of human judgment. Kahneman and others in his field divide our decision-making process into two systems: System 1, with its nearly instantaneous impressions of people and situations; and System 2, with its rational analysis and ability to handle complexity. These two systems compete and sometimes overlap, acting as checks on each other.

System 1

System 2

That long-haired guy looks suspicious.

That baseball player reminds me of a young David Ortiz, but appearances can be misleading.

The stock market is going down — I better sell NOW! This system generally offers preferences based on patterns picked up by our brains without our awareness. This is the source of both unconscious biases that may lead to bad judgments, and the insight from experts with significant experience in a specific situation. This system “tends to be fast, non-conscious and emotionally charged,” says Michael Pratt, a professor of organizational change at Boston College. Neuroscientists often call this implicit knowledge. According to Paul Reber, a neuroscientist at Northwestern University, it is the result of connections between groups of neurons that form throughout the sensory cortex after repeated exposure to two or more stimuli together or in quick succession.

QUALITIES Fast, Automatic, Associative

ADVANTAGES It is faster and can take on an automatic quality, which makes it useful for high-pressure, highstress situations, like combat or a basketball game. It can be harnessed and, through training, be used to speed up reaction times and save mental energy.

DISADVANTAGE It’s not the best system for some kinds of structured problems, such as those based on math, in which there is one correct answer. Its predictions and assumptions based on the sum of previous experiences might not represent current reality. It is vulnerable to unconscious biases.

I should ignore the compulsion to sell when the stock market is going down. That is just fear talking. These decisions are analytical, deliberate and “rational.” A dualistic notion of decision-making has been around forever. “People assume that System 1 is bad and System 2 is good,” says Pratt. ”People have been unreflective about that until recently.” Neuroscientists have traditionally called the information we use to make these decisions explicit knowledge. It relies on the traditional memory systems of the brain, such as the hippocampus and the prefrontal cortex, the integral component of working memory. One might liken the hippocampus to the brain’s filing clerk for long-term memories — lose it, and you become an amnesiac, incapable of retrieving memories or storing new ones. The prefrontal cortex is the seat of the brain’s executive function. That’s where we hold information we need temporarily to calculate how much to pay the babysitter or what to buy for dinner.

QUALITIES Slow, Controlled, Rule-Governed

ADVANTAGES It allows you to consider the consequences of a decision before you make it. Also, it allows the application of complex rules and information; studied, analytical thought; and analysis. And it can insulate you from the corrosive effects of fear and emotions.

DISADVANTAGE It’s slower and can break down under stress, causing you to “choke.”

July/August 2017 DISCOVER

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EVERYTHING

WORTH

KNOWING

How We Decide

A Tale of Two Horses Ancient Greece Plato compares the human will to a charioteer, driven by two horses, one representing our rational or moral impulses, and the other our irrational passions and appetites. Late 18th century Italian criminologist and economist Cesare Beccaria publishes an essay called “On Crimes and Punishments,” which would form the basis of what’s called rational choice theory: People will act in their own best interest. Beccaria argued for the principle of deterrence in dealing with crime. He contended that punishments should be just severe enough to offset any benefit from the crime. Beccaria’s ideas would establish the foundation of modern economic theory. 1890 Psychologist William James provides what some consider the modern origins of dual process theory,

speculating that there are two ways that people decide: associative and true reasoning. 1936 Management theory pioneer Chester Irving Barnard argues that mental processes fall into two distinct categories: logical (conscious thinking) and non-logical (non-reasoning). Although the categories could be melded, Barnard believed, scientists relied mainly on logical processes, and business executives on non-logical when making decisions. 1950s Herbert Simon analyzes the role of intuitive decisionmaking in management in a scientific way. When people make decisions, their rationality is limited by time and knowledge. Choices are, by necessity, “good enough,” Simon says. 1953 A patient known as

4 H.M. undergoes experimental brain surgery to halt his

Implicit Learning

4

In 1953, a patient named Henry Molaison underwent an experimental brain surgery that halted his seizures. But then Molaison couldn’t form new long-term memories. His misfortune made him famous. By studying “H.M.” and other amnesiacs, neuroscientists were able to prove the role of the hippocampus and related structures in long-term memory formation. Molaison’s experiences also shed light on unconscious, or implicit, learning. Molaison was given a battery of tests, which confirmed his complete inability to form long-term memories. But one test contradicted the other results. Given the test 10 times across three consecutive days, he traced a star on paper using a barrier and mirror. His speed increased steadily, but each day when he arrived at the lab, he had no memory of learning to trace the star. Years later, Molaison was shown 20 line drawings of common objects and animals in a series of sessions. He eventually was able to identify the drawings even with mere fragments. An hour later, he had no memory of ever taking the test. Yet when he took it again, his scores still improved. On some level, he had retained his ability to correctly classify the fragments. This form of learning is now known as implicit learning.

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epileptic seizures. For the first time, researchers find that decisions based on unconscious learning, or knowledge we don’t know we know, may rely on entirely different brain pathways than the parts of the brain we use when we make conscious, rational choices. Late 1960s In a series of experiments, psychologists Daniel Kahneman and Amos Tversky demonstrate the downside of the way humans make decisions, identifying several unconscious, systemic biases that consistently distort human judgment. Kahneman would win the 2002 Nobel Prize in Economics for this work. (Tversky died in 1996.) 1979 Kahneman and Tversky introduce prospect theory, which describes how people make choices in the face of risk. Individuals are more likely to base their decisions on the potential value of losses and gains and how those gains and losses will

4

make them feel. Scenarios that are more vivid or emotionally charged can exert more power than less emotionally charged but equally probable scenarios.

4

1998 Psychologist Gary Klein publishes Sources of Power, based on his earlier work in the mid-1980s. The book would form the basis for the new field of naturalistic decision-making. By studying experienced firefighters, military commanders and nurses, Klein contended that intuition was not inherently bad — it’s just less accurate when based on limited experience. He argued that experts make decisions in high-stress situations, under time pressures, with a blend of Systems 1 and 2: They notice patterns, get an intuition on how to handle it, and then use System 2 to simulate and evaluate that intuition.

Unconscious Biases

4

Starting in the late 1960s, Kahneman and Tversky began a collaboration that would eventually overturn the way people thought about decision-making in medicine, economics and a wide range of other fields. They focused on heuristics — a series of unconscious rules or biases — and how they can consistently lead us in the wrong direction. The simplest and most powerful one is called the availability heuristic. Sometimes we grasp for the wrong answer on instinct, simply because it is easier to access and thus “feels” correct. Kahneman and Tversky designed and administered a series of questions to university students — and their answers consistently went against what one would consider rational thinking. Students listened to recordings of lists of 39 names read aloud. Some of the names were very famous people, like Richard Nixon, and others were public figures who were less well-known. One list had 19 very famous male names and 20 less-famous female names. A second list included 20 less-famous male names and 19 very famous female names. The students were then asked whether the list of names included more men or more women. When the men in the list were more famous, a majority of participants incorrectly thought there were more men on the list, and vice versa for women. Tversky and Kahneman’s interpretation: Judgments of proportion are based on “availability.” Students could more easily connect with the names of better-known people.

High4 Stakes

BRAIN ILLUSTRATIONS: EVAN OTO/SCIENCE SOURCE. NEURONS BY JAY SMITH

Decisions In the 1980s, Klein wanted to know how people made really hard decisions under extreme time pressure and uncertainty. First responders and experienced military commanders seemed to make decisions — the right decisions — under pressure all the time. How did they do it? To get to the bottom of this phenomenon, Klein visited fire stations across the Midwest. When he started out, Klein suspected that expert commanders picked a limited range of options to choose from and then carefully weighed the pros and cons. Klein expected a rational, logical approach to unfold in every commander’s conscious mind — an approach based on System 2. To his surprise, Klein consistently found the commanders looked at just one option. They “knew” what to do. By the time they became aware of the approach, they’d already decided. Sometimes after the best approach popped into their mind, they consciously imagined how it would play out before actually implementing it, to make sure it would work. But for the most part, their first idea was the only one they considered. “It really shook us because we didn’t expect that,” Klein recalls. “How can you just look at one option? The answer was that they had 20 years of experience.” Twenty years’ experience gave the firefighters the ability to do what Klein called pattern matching. The process seemed to involve complicated analysis of sensory information that occurs, somehow, entirely without their awareness. After the best approach popped into their heads, the commanders didn’t compare it with others. Instead, they just acted, their thought process akin to the muscle memory of a trained boxer. “It was unconscious, it was intuitive, but it wasn’t magical,” Klein says. “You look at a situation and you say, ‘I know what’s going on here, I’ve seen it before, I can recognize it.’ ”

A Split Decision The brain’s two systems aren’t exclusive of each other. They depend on shared connections and experience.

SYSTEM 1

Sensory cortex (brown) Basal ganglia (orange)

The basal ganglia, which helps strengthen the speed of circuit formation, and the sensory cortex are major players. In the sensory cortex (shown in detail above), groups of neurons develop patterns of firing that are re-established more easily with repeated exposure to stimuli. This is key to those split-second decisions, made under pressure.

Hippocampus (red)

Prefrontal cortex (purple)

SYSTEM 2 The prefrontal cortex, which is the seat of the brain’s executive function, and the hippocampus — crucial to memory storage and recollection — work together as the foundation of explicit, rule-based decision-making.

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EVERYTHING

The Future of Food

KNOWING

How we’ll serve 10 billion.

WORTH

BY KATHERINE MAST ILLUSTRATIONS BY KELLIE JAEGER

Fifty years ago, two paradigms clashed over how to handle a growing population. Some preached curtailed growth, while others believed human ingenuity could meet the challenge. Stanford University biologist Paul Ehrlich predicted many millions of people would starve in the 1970s and ’80s. The only solution, he wrote in the book The Population Bomb, was to curb birthrates. But plant geneticist Norman Borlaug developed a high-yield, disease-resistant dwarf wheat that boosted global agricultural production — the Green Revolution. He persuaded developing countries to adopt this new seed — and later, an improved rice — ultimately tripling global cereal grain yield. Borlaug won the Nobel Prize in 1970. As the world braces for another population bomb, scientists are still chasing the next Green Revolution.

PROBLEMS A WARMER WORLD POPULATION BOMB Seven billion people now live on Earth. By 2050, the population is expected to hit 9.7 billion. Even though the rate of malnutrition has fallen globally in recent decades, nearly 800 million people still don’t have enough food. To feed the world in 2050, food production must increase by 70 percent.

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CALAMITIES Agricultural diseases and pests — age-old problems — are amplified by climate change. As the cold season gets warmer, winter’s killing frost will do less to keep crop-eating insect populations under control. And this warmth, along with stronger storms and altered precipitation, will spread diseases where they once weren’t a problem.

Climate change will bring bigger storms and more frequent droughts, as well as desertification in places like sub-Saharan Africa. Precipitation patterns will change, affecting agriculture, though it’s not certain how. These effects could be strongest in the Southern Hemisphere, home to the most rapid population growth.

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SOLUTIONS

BOOST YIELD ON THE LAND WE HAVE Urban expansion coupled with land lost to climate change means growing more crops on less land. Biotechnology has increased yield by introducing new crops designed to resist pests and disease, and to withstand weed-killing herbicides. Now, nearly all American corn and soybean farmers grow genetically modified seed. Certain varieties of genetically engineered squash, tomato and potato haven’t been as widely adopted. Future genetically modified organisms (GMOs) could be more heat- and drought-tolerant and provide better nutrition. And the gene-editing technique CRISPR could soon let scientists tweak DNA with new speed and precision, leading to breakthroughs in crop breeding. Experts say CRISPR could make traditionally low-yield crops, such as quinoa and wild legumes, more farmable, and even introduce traits that took thousands of years of breeding, like reduced bitterness, into plants that have never been farmed. But GMOs are no silver bullet. They don’t deal with the ecological problems of modern agriculture, like erosion and lack of soil biodiversity, critics say. So other researchers are developing perennial crops that produce year after year, and cultivating microbial diversity in the soil to boost yield and nutrition.

2 5

EAT AN ANT Mealworms, termites, beetles and ants: Diets around the world feature insects for protein, yet bugs on the menu make a Westerner’s stomach turn. It’s time to expand our palates. Insects are packed with easily accessible proteins and nutrients; humans can digest about 80 percent of an insect compared with just 50 percent of a chicken or pig. And they’re easier on the environment than largescale livestock operations. When comparing beef versus bug protein pound for pound, cattle need 10 times more land than mealworms.

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EMBRACE ‘UGLY’ PRODUCE About one-third of all food never makes it from farm and table. Corporations are trying to transform our ideas about the perfect piece of produce by encouraging people to eat “ugly” fruit. Supermarkets in France can now be fined for dumping food that is old yet still edible. But it’s more than just fines for supermarkets. Stopping food waste means education campaigns, meal portion sizing and removing expiration dates on foods that don’t really expire.

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MEGAFARM-TOTABLE SHORTCUTS

TOILET TO TAP Water, water everywhere, but not a drop to drink — or use for irrigation. Reclaimed wastewater — graywater, sewage effluent and other waste — might seem gross, but if handled correctly, it can be a nutrient-rich way to irrigate crops. In places like Egypt, Jordan, central Mexico and even the U.S., it already is. A similar, but costlier, technique can transform salty water into usable drinking and irrigation water.

The typical American meal contains ingredients from five countries. This kind of globalized food trade has ecological and economic impacts. Regional food hubs can shorten the distance from farm to market.

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EVERYTHING

Catching a Criminal

KNOWING

Getting an edge with high tech and lowly microbes.

WORTH

BY JONATHON KEATS

The Chinese sickle slaying is one of the first reported cases of forensic investigation. The role of science in evidence collection and presentation has only become more important over time, and it continues to evolve at an ever-accelerating pace. New discoveries are bolstering even the oldest techniques, such as fingerprinting, first systematized by Englishman Sir Francis Galton in 1892. For instance, in 2015, National Institute of Standards and Technology chemist Shin Muramoto found that ridges on a fingerprint release a substance known as palmitic acid at a predictable rate, allowing investigators to determine when prints were laid down and whether they’re temporally relevant to a crime. And at the University of Albany, chemist Jan Halámek recently published a method to determine the

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sex of the person who left a print based on proportions of amino acids found in skin oils. One of the most significant developments in forensics — the advent of DNA profiling in the 1980s — also continues to advance. More than just a means of tying a suspect to a crime scene, genetic information can reveal clues about a culprit’s appearance through a process called DNA phenotyping. Indiana UniversityPurdue University Indianapolis geneticist Susan Walsh has successfully predicted eye and hair color based on genetic markers known as single nucleotide polymorphisms (SNPs), and Pennsylvania State University anthropologist Mark Shriver has used SNPs to make predictive digital mugshots. DNA phenotyping has met some skepticism, which is important given an individual’s freedom may be on the line; overconfidence and pseudoscience both have a long and tragic history in forensics. Exhibit A: Galton, the father of fingerprinting, falsely claimed that criminal tendencies could be detected in the faces of people who physically resembled known lawbreakers. Last year, a study released by the President’s Council of Advisors on Science and Technology raised a fresh round of concerns, finding inadequate scientific support for standard techniques ranging from ballistics testing to blood spatter analysis. However, forensic science is also a powerful technique to scrutinize itself, as researchers discover and correct past inadequacies. Studying the reasons why blood spatter can be misleading, Loyola University Maryland biologist David Rivers recently observed that the blood was sometimes spread by flies. So in a move that would surely have impressed medieval China’s CSI, Rivers developed a spray that could distinguish bug-borne spatter by detecting fly gut enzymes in bloodstains. Check out some other cutting-edge ways researchers are advancing established investigation methods.

PASIEKA/SCIENCE SOURCE

In 13th-century China, a field worker was killed with a sickle — and all villagers’ sickles were alike. So the investigator had every worker lay down his tool in a field, and observed that just one sickle attracted blowflies, which were known to seek out blood. Its owner, the culprit, immediately confessed.

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Examining the Victim

When investigators find a body, they want to know how long ago the victim died. There are numerous established techniques, but each has significant limitations. Rigor mortis isn’t very precise over extended periods, and the presence of telltale insects varies by region. In contrast, “microbes are always present at a death scene,” says Colorado State biologist Jessica Metcalf. And the rise

and fall of microbial populations follows a reliable course as a corpse decomposes, even though the actual pace of activity varies widely due to temperature and other environmental factors. Over the past several years, Metcalf and colleagues have developed a “microbial clock” to measure postmortem passage of time by genetically sequencing the population of microbes on the skin and in the surrounding soil. Their experiments at body farms — outdoor facilities where scientists study the decomposition of donated cadavers — have established a timekeeping accuracy of two to four

days over a 25-day period. The microbes can also show whether a corpse has been moved and reveal the original location. Tools from metagenomics — sampling trace genetic material in the environment — and methods of studying the human microbiome are providing insights into disease while bolstering the crimefighting potential of bacteria and fungi. “We’re also working on using skin microbes as trace evidence to link people to objects they recently touched or spaces they have recently occupied,” says Metcalf. Invisible and ubiquitous, microbes are the ideal witnesses.

MICROBIAL CLOCK

6. Following additional breakdown by microorganisms, including saprotrophic fungi, the cadaver dries out. Bacteria such as Sporosarcina consume remaining compounds.

BACTERIA: KATERYNA KON/SHUTTERSTOCK. FEET: PICTURE PARTNERS/SCIENCE SOURCE

5. The abundance of microbial biomass provides food for microscopic worms.

4. The corpse ruptures. Oxygen enters the body, along with an abundance of aerobic microbes from the surrounding soil.

1. Upon death, the immune system shuts down, allowing internal microbial populations to flourish. Their activity produces gases, causing the body to bloat.

2. As cells die, bacteria from families such as Moraxellaceae and Enterobacteriaceae consume them, beginning the process of decay. In addition, Enterobacteriaceae may attract insects, which further aid decomposition.

3. Bacteria in families such as Rhizobiaceae and Chromatiaceae break down nitrogen sources.

Note: This is just a small sampling of the many microbes involved in decomposition.

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EVERYTHING

WORTH

KNOWING

Catching a Criminal

2

Investigating the Scene of the Crime From protein markers for hair, to microbial clocks for cadavers, to sprays for detecting fly gut enzymes in blood spatter, the tools and techniques of forensic investigation now extend beyond the expertise of any single investigator. As a result, the enzymes, microbes and proteins that could prove crucial to catching a criminal might easily be overlooked at the scene of a crime. Bringing in large groups of experts

View recorded by camera

would be impractical, wasting precious time and potentially contaminating evidence. Working in collaboration with the Dutch National Police, researchers at the Delft University of Technology have come up with a solution that looks somewhat like Pokémon Go: arm CSIs with augmented reality (AR). Investigators wearing shouldermounted cameras allow off-site specialists to observe the investigation in real time. They can even annotate the crime-scene video feed with text and arrows that the CSI on the ground can see on a wrist-mounted screen or through glasses like Microsoft’s HoloLens. “The mobile policemen will be

Microsoft HoloLens

able to get in contact with remote experts and solve cases more easily together,” explains Dragoş Datcu, a former Delft University of Technology researcher who now heads research for a Dutch AR company called Twnkls. Twnkls plans to commercialize the system for law enforcement by the end of the year. If it catches on, the Sherlock Holmes of the future may find himself with a desk job.

INVESTIGATOR AT SCENE

OFF-SITE SPECIALIST

Transmits view using shoulder-mounted camera

Adds notes in real time

Investigator can see notes on wrist camera or glasses Shared display is visible to both parties

Annotations placed on live video feed of the crime scene

SOFTWARE ANNOTATION OPTIONS 3-D arrows highlight points of interest

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Area to record with laser scanning

Warning to avoid an area

Areas to analyze for prints

Take DNA samples for analysis

Barcodes tag other potential evidence

Team notes

Potential dangerous substances

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AUGMENTED REALITY

TOP: ALISON MACKEY/DISCOVER AFTER LAWRENCE LIVERMORE NATIONAL LABORATORY/RESEARCH HIGHLIGHTS/A NEW ROLE FOR HAIR IN HUMAN IDENTIFICATION. BOTTOM FROM LEFT: JULIE RUSSELL/LLNL (2); PARKER ET AL./ JOURNAL.PONE.0160653

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Identifying the Culprit

DNA profiling is universally accepted as the highest standard for identification in forensics, and it has been used successfully for decades to convict or exonerate suspects. In fact, a 2009 National Research Council report on forensic science eviscerated all other identification techniques, from fingerprinting to bite mark analysis, holding DNA as uniquely capable of reliably distinguishing between any two people on Earth. But DNA also has limitations. It can degrade and be difficult to extract from trace evidence, such as skin and hair. So Glendon Parker, a biochemist Amino acids

Proteins are made up of amino acids. A peptide is two or more amino acids linked in a chain.

at the University of California, Davis, has been studying unique markers in the proteins made by DNA. “The major advantage is that protein, particularly hair protein, is more stable than DNA,” he explains. Protein-based identification relies on the mechanism that makes DNA valuable for forensic identification. Single nucleotide polymorphisms (SNPs, used as genetic markers in DNA profiling) can produce single amino acid polymorphisms (SAPs) in the amino acids that make up protein. The challenge for criminal investigation is to find a set of SAPs that can be easily isolated and are collectively unique for each

HOW POLYMORPHISMS CAN PINPOINT A PERSON

DNA sequence

REFERENCE CODONS

VARIANT CODON

...GGT AGA TGC...

...GGT AG T TGC...

Gly Protein sequence

Protein

human being. Parker and his colleagues have already identified more than 100 protein markers, which together can pinpoint one person out of 15 million. They’ve also shown that these proteins are stable enough in hair to identify 250-year-old human remains. “However, there is a gap between feasibility and implementation,” Parker notes. “We still need to optimize sample processing so a single hair can be analyzed.” And they need to find the SNPs that can identify one person out of 7.4 billion. He gives it a few years, and in the interim expects to extend his technique to skin flakes. Criminals with dandruff, beware!

Arg

Cys

...Glycine Arginine Cysteine...

Gly

Ser

Cys

Single nucleotide polymorphism (SNP) Single amino acid polymorphism (SAP)

...Glycine Serine Cysteine...

A grouping of three nucleotide bases in a DNA sequence is called a codon. Each codon provides instructions for creating a specific amino acid. Variations from the reference genome are called polymorphisms and can be used as identifying markers. In this example, changing a single DNA nucleotide from A to T creates the amino acid serine instead of the expected arginine.

HAIR ANALYSIS: HOW IT WORKS 1. Hair from the crime scene is milled and processed to break the proteins into smaller peptides. 2. The peptide mixture is dissolved and ionized, and then routed into a mass spectrometer.

3. The instrument measures the weight of the peptide and the weights of all the pieces of the peptide when broken up. The pattern that the fragments’ weights create can be used to match the peptide to a sequence of single amino acid polymorphisms (SAP).

4. When a specific SAP is found in the peptide sequence, the investigator knows that individual had the DNA to produce that polymorphism. If the polymorphisms in all the peptide sequences are consistent with those of a suspect, then that suspect can be associated with the evidence. 5. The more marker peptides detected and compared, the greater the probability that the match is unique to the suspect. Protein markers create a pattern.

Biochemist Glendon Parker holds a sample of human hair.

Mass spectrometer

July/August 2017 DISCOVER

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EVERYTHING

When We Left Water

KNOWING

How our tetrapod ancestors first came ashore.

WORTH

BY GEMMA TARLACH

Surf to Turf While the fossil record from this slice of the Paleozoic Era is too incomplete to say whether any of these animals were directly related or just distant cousins, the species represent the transitional nature of the vertebrate move from water to land.

More than 350 million years ago, our distant fishy ancestors traded in the life aquatic for land. Once ashore, these four-limbed vertebrates, called tetrapods, branched into an impressive range of animals: amphibians, reptiles, dinosaurs, birds and mammals. The fossil record shows that as species evolved to fill particular ecological niches, a few of the tetrapod clan lost limbs (snakes), turned arms into wings (bats, birds and pterosaurs) or decided the heck with dry land and headed back to sea (including whales, seals and some marine reptiles). The tetrapods’ move to land has long been one of the great evolutionary puzzles. Fossil finds from this transitional period are too few to explain why or how it occurred, or exactly when the first fully terrestrial tetrapods evolved. Even so, researchers are getting closer to piecing it all together. The tetrapod story starts with lobe-finned fishes nearly 400 million years ago. Unlike ray-finned fishes, which make up the majority of fish species today, the lobe-finned varieties evolved with bony limb-like fins, a handy adaptation (no pun intended). During the late Devonian period, starting about 375 million years ago, transitional “fishapods,” with both primitive, fish-like traits and adaptations for semi-aquatic living, begin to appear in the fossil record. Although these species had evolved stronger limbs with defined digits, they still

375 million years ago

Eusthenopteron: Known from thousands of fossils, the lobe-finned fish’s four meaty limbs have the same pattern of bones seen in the limbs of all tetrapods: a single bone nearest the body (your arm’s humerus and your leg’s femur), two bones farther out (your arm’s radius and ulna and your leg’s tibia and fibula).

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Tiktaalik: Found at a single site in the Canadian Arctic, this transitional fishapod had a number of skeletal quirks, including 45 or more vertebrae. It also had the beginnings of a neck and a primitive wrist, as well as a middle ear — tetrapod traits not seen in fish. ILLUSTRATIONS BY JAY SMITH

385 million years ago

weren’t truly tetrapods. “All of them are a little weird,” says Cambridge University professor emeritus Jennifer Clack, the grand dame of early tetrapod research. “None of them are like tetrapods from later on. Thirty million years later, they’re running about.” Researchers have yet to find the species that can link early fishapods with fully terrestrial tetrapods. We may be closer to understanding how the transition happened, however. In the early tetrapod hotspot of southern Scotland, for example, researchers discovered that tetrapods apparently moved to land during a wetter period: Many of the tetrapod fossils turning up there have been found in what were seasonal floodplains. It’s possible that aquatic tetrapods swam into shallow waters — or were washed in during storms or seasonal monsoons. There, vegetation may have sheltered them from the sun, preventing them from drying out. As researchers continue to hunt for the first landlubbers in our lineage, here’s what we know so far.

An Acanthostega fossil

350 million years ago

TOP: SCIENCE STOCK PHOTOGRAPHY/SCIENCE SOURCE

365 million years ago Acanthostega: Like its rough contemporary Ichthyostega, another early tetrapod, this creature had evolved digits — lots of them, as many as eight per limb. Acanthostega is also the first tetrapod with a sacrum, strengthening the pelvis-hind limb connection. Researchers believe it was still fully aquatic but may have “walked” in the shallows.

Pederpes: This Scottish find is the earliest with five functional digits, a pattern that would dominate later tetrapods. The roughly meter-long animal also appears to have been capable of four-limbed locomotion on land, though researchers believe it spent at least some time in the water.

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EVERYTHING

WORTH

KNOWING

When We Left Water

How to Be a Landlubber Terrestrial life required four key adaptations for aquatic tetrapods.

1

LOCOMOTION

Lobe-finned fish

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2

RESPIRATION The common ancestor of both ray-finned and lobefinned fishes had primitive internal air sacs that allowed them to breathe air. For ray-finned species, these sacs evolved into bladders for buoyancy control. For lobe-finned fishes’ tetrapod descendants, however, the sacs evolved into lungs. Moving around on land required significantly more huffing and puffing — and oxygen — than swimming for early tetrapods. Some researchers believe the atmosphere when vertebrates were heading ashore had significantly higher levels of oxygen (30 to 35 percent rather than today’s 21 percent), which may have made moving on land easier for the animals.

FOOD ACQUISITION If you crawled or crutched your way from water onto land, your biggest challenge wasn’t breathing or moving around; it was swallowing your food. In water, fish can change the pressure in their mouths to force water and food, which have about the same density, into their esophagus. On land, the difference in density between air and food makes that mechanism a no-go, and helpful adaptations such as tongues and specialized jaw shapes would not evolve until millions of years after the transition to land. A 2013 study found that modern eel catfish grab prey on land with their jaws but return to water to swallow the meal. It’s possible transitional tetrapods did the same thing.

A Tiktaalik fossil

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Ichthyostega reconstruction

DISCOVERMAGAZINE.COM

Eel catfish

4

SENSORY SYSTEMS In March, researchers found that tetrapod eyes tripled in size just before they transitioned to land. While that kind of increase would not have helped the animals see better while swimming, it would greatly expand their vision out of water. At about the same time, the eye position moved from the side to the top of the skull, as seen on some transitional species, such as Tiktaalik. The combination of better vision out of water and eye location suggests that these fishapods may have hunted like modern crocodiles, lying in wait in the shallows to ambush prey on the shore.

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The muscles and bones in lobe-finned fish appendages gave tetrapods, ahem, a leg up on adapting to life on land. The first vertebrates to forsake the seas probably didn’t walk or even crawl, however. A 2012 reconstruction of early tetrapod Ichthyostega suggests that it couldn’t bend side-to-side like lizards do as they walk. It’s more likely the animal “crutched,” like the modern mudskipper, using both front limbs simultaneously to propel itself forward. The shoulders and pelvis of early tetrapods expanded and strengthened, allowing for load-bearing on land.

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The Trouble With Trackways

Mind the Gap

In 2010, the apparent discovery of terrestrial tetrapod tracks in Poland’s Zachelmie quarry made headlines. At more than 390 million years old, the trackways would predate by tens of millions of years the period we thought tetrapods left water for land. In 2015, however, another study suggested the depressions were from a fish nest, or imprints of a fish feeding in a circular pattern. Until researchers find bones associated with the “trackways,” or at least from the same period, we can’t be confident about what animal made them, or how.

Burnmouth Harbor, shown at low tide, is one of several sites in Scotland where researchers dug for tetrapod fossils. The work, part of a project called TW:eed, paid off. In 2016, team members described five new species of tetrapods from Romer’s Gap, a span of millions of years nearly bereft of tetrapod discoveries.

A group of scientists believed the fossilized imprints in this slab were made by a tetrapod moving in a manner shown in the illustration on top. But that theory was called into question in 2015.

Some of the most exciting research on tetrapods has come from an interdisciplinary project based in the United Kingdom. Tetrapod World: early evolution and diversification (TW:eed) re-created the environments these distant relatives called home. The team also continued filling in Romer’s Gap, a span in the fossil record from about 335 million to 360 million years ago that had long vexed paleontologists. On the far side of the gap, named after Alfred Romer, the Harvard University researcher who first noticed it, tetrapods are rare and ill-adapted for terrestrial living. Fast forward to after the gap, and we see a diverse assortment of terrestrial tetrapods. TW:eed researchers focused on a handful of sites in Scotland, which was much closer to the equator and had a tropical climate when tetrapods were first coming ashore. In late 2016, team members described five new species of tetrapod and identified fragmentary remains of at least seven more, all from the Romer’s Gap era. Thanks to detailed study of the layers in a 500-meter-deep borehole at one of the fossil sites, TW:eed members were able to determine the tetrapods’ habitat was a mosaic of braided rivers Alfred Romer and floodplains, with distinct dry and wet seasons. While some invertebrates had transitioned from marine to terrestrial environments millions of years earlier, even more came ashore during this period, along with the tetrapods. Carys Bennett, a geologist at the University of Leicester who specializes in sedimentology and microfossils, says Romer’s Gap is becoming a misnomer as more species remains are discovered. “It’s full of life,” she says of the era. “It was a thriving time.”

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EVERYTHING

Virtual Reality

KNOWING

You’re almost there.

WORTH

BY STEPHEN ORNES

Forget reality: In virtual reality, you can be whomever and wherever you want. VR makes the unreal real, using computer software and hardware that responds to our body’s movements to immerse us in a convincing alternate existence.

In 2014, the VR tech market totaled a paltry $100 million in sales. But in just three years, virtual universes have undergone a very real big bang — financially. Sales of software and hardware should approach $5 billion this year. And if these trends continue (a decentsized “if”), some analysts say sales could skyrocket to $38 billion by 2020. 2016 $1.8 billion 2017 $4.9 B 2018 $13.6 B 2019 $23.4 B 2020 $37.7 B Source: Superdata

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Medical Applications VR goes beyond fun and games. Doctors, engineers and inventors want to help people with real-world medical problems using alternate realities. Conquer fear. Afraid of flying, spiders or tight spaces? VR exposure therapy may help reduce anxiety through gradual, safe and realistic contact with what haunts you.

Manage prosthetics. Amputees can retrain muscles associated with lost limbs in virtual environments — and take new artificial limbs for a test drive.

Curb PTSD symptoms. VA hospitals and others have begun using VR treatments that allow soldiers to safely revisit traumatic memories.

Avoid falls. A recent study showed a decreased risk of falling in people with Parkinson’s disease who engaged with a kind of VR.

Evolution of the Multi-Metaverse

machine combining 3-D film, sound and smells, amounts to little more than a fad.

1935 “Pygmalion’s Spectacles,” a short story, features a holographic

1984 William Gibson’s novel Neuromancer introduces the “matrix,” a VR space populated

DISCOVERMAGAZINE.COM

personal details: In most VR worlds, you can’t see where other people are looking, or what they’re doing with their hands. But while VR is famous for overpromising and underdelivering, Rosedale sees progress being made on these fronts — think eye-tracking sensors, or gloves that communicate gestures. Within a few years, personal VR meetups could be startlingly personal. The future is exciting, but uncertain. VR environments — including headsets — can trigger motion sickness. And critics warn that we’re becoming increasingly isolated and risk addiction or physical harm. Champions say VR brings us together. The only certainty is that as this tech experiment evolves around us, we’re all lab rats in the least natural environment imaginable — one entirely invented by humankind.

immersive experience. 1950s Sensorama, a phone-booth-like

Patients walked on a treadmill while watching a real-time video of their own feet walking. In the six months after the exercise, patients who trained this way saw a 50 percent reduction in their rate of falls compared with patients who’d only walked on a treadmill. Live without chronic disease. Alternate worlds like Second Life also offer a place where people who have chronic diseases can leave their physical bodies behind and interact with other people online.

by humans and artificial intelligence.

an immersive virtual experience.

1989 VPL Research introduces the data suit, which includes sensors all over the body and a bulky headset that turns sensory data into

1990s Online users flock to text-based virtual worlds. Early VR games, including Dactyl Nightmare, begin appearing.

WILLIAM ZUBACK/DISCOVER

The Money

There’s plenty of space to roam. VR places can be huge. In Second Life, an early pioneer of virtual worlds, you can attend university, own a blimp, have blue fur — whatever. It includes more than 600 square miles of otherworld existence. The worlds of Minecraft, another digital sandbox, could cover Earth eight times over. The possibilities are endless. VR movies offer new vehicles for narrative structure. VR classrooms may reach students who don’t thrive behind a desk. Soon, we may have virtual meetings, conferences, classes and parties. According to tech entrepreneur Philip Rosedale, who founded Second Life, “We have an insatiable appetite for communicating with each other. VR is the next medium in that regard.” Right now, the visual fidelity of these worlds remains somewhat blocky and lacks

THE TECH

Five Senses Our perceptions are shaped by sounds, sights, feels, tastes and smells. A convincing VR world needs to hit all those buttons.

What you see: VR goggles display 3-D landscapes using slightly different sideby-side images, one for each eye. Embedded sensors monitor head movements and shift the scene accordingly. Microsoft’s HoloLens even displays virtual objects overlaid on the real world; it’s often referred to as an AR, or augmented reality, device.

1992 Neal Stephenson’s novel Snow Crash showcases the Metaverse, a virtual mega-reality where people connect through the internet. 2000s Engineers create room-sized boxes that

What you hear: VR sounds have to line up with the visuals. That often means recording with multiple microphones and linking sounds to virtual locations or objects.

What you taste: Epicures, rejoice! Researchers have unveiled devices that mimic the sensation of tasting foods. A “digital lollipop,” for example, stimulates the taste receptors with vibrations and electric signals to simulate flavors. Relish the meal, forget the calories.

combine sound and projected images with headsets to make immersive virtual spaces. 2003 Launch of Second Life, an online 3-D fantastical facsimile of the real world.

What you smell: Soon, you might smell things that aren’t there. A company called FeelReal is building a mask containing odor capsules that let a user smell the flowers — or other odiferous objects — within a virtual world (similar to the ride Soarin’ at Disney’s Epcot Center). What you feel: Haptic devices use ultrasound to create midair illusions that you can touch and move. Can you hug someone halfway around the world? Not yet, but someday.

2014 Launch of Google Cardboard, a cheap headset that turns a user’s smartphone into a VR platform. 2015 SpatialOS debuts, a platform for coders to create seamless virtual

worlds for thousands of gamers. 2016 High Fidelity, a company from Second Life designer Philip Rosedale, launches a new VR platform for world-building.

2016 Wide release of the Oculus Rift, HTC Vive and PlayStation VR, high-powered consumer headsets that let users move around in a VR environment.

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Asteroids

KNOWING

World killers. Life builders. And they could be worth trillions.

WORTH

BY NATHANIEL SCHARPING ILLUSTRATION BY ROEN KELLY

Our early solar system was a wild place. Dust grains grew into pebbles, and pebbles became world-building planetesimals. These rocks spun around and bumped into each other in a chaotic dance that left a trail of debris in its wake. The remnants of these festivities remain strewn about our cosmic backyard. Many rocky and metallic bodies now orbit in what’s called the Main Asteroid Belt, between Mars and Jupiter. More than just leftovers, asteroids offer clues to the earliest days of our solar system, as well as the promise of valuable minerals and precious resources. Assuming they don’t kill us first.

Hayabusa2 As the successor to the first asteroid sample-return mission, Japan’s Hayabusa2 hopes to make an even bigger impact — literally. It will ram open a crater to gather subsurface materials.

Seek and Destroy The key to protection is detection. A recent U.S. government report proposed seven steps for an asteroid survival plan. The most important: Work together and find them fast. Future projects, like the Large Synoptic Survey Telescope and NASA’s NEOCam, will scan the sky for incoming threats.

Near-Earth Objects We’ve found more than 15,000 near-Earth objects (NEOs) — comets and asteroids — but there could be hundreds of thousands more out there. And they are indeed near: About 50 passed between Earth and the moon last year.

OSIRIS-REx Launched in 2016, the NASA mission will map asteroid Bennu and even bring back a piece.

Mining Estimated to be worth billions or even trillions, the asteroid rush has already begun. Two U.S. companies, Deep Space Industries and Planetary Resources, already have prototype mining probes. The companies’ goal: bring an asteroid close enough to collect rare-earth metals and water for future missions.

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Trojans Two separate groups of asteroids, known as the Trojans, are ensnared by Jupiter’s gravity. Their numbers could rival that of the Main Belt asteroids.

Lucy Mission NASA’s Lucy spacecraft is set to swing by six of Jupiter’s Trojans beginning around 2025 to get an up-close view of this still-mysterious group of ancient asteroids. Main Belt Chill out, Han Solo. Although the Main Belt is populated by millions of asteroids, the odds of hitting one are tiny. They’re separated by at least twice the Earth-moon distance on average.

Ceres NASA’s Dawn spacecraft recently brought the largest asteroid into view. It’s an active world with evidence of ice volcanoes and an ancient ocean.

SPACECRAFT, CLOCKWISE FROM BOTTOM LEFT: BRYAN VERSTEEG/DEEP SPACE INDUSTRIES; NASA; JAXA; NASA (3). MAP BY EKLER/SHUTTERSTOCK

COMPOSITION

Psyche Mission Scientists think the allmetal asteroid Psyche was once the core of a protoplanet. A NASA mission of the same name will visit the 150-mile-wide nickeliron body in 2030 to find out. Panspermia Life might have a cosmic origin. We know some precursor molecules came to Earth from space because amino acids are found in meteorites — fallen space rocks. But some scientists believe life might have started on Mars and traveled to Earth after impacts.

Metal asteroid

OIron ONickel OCobalt

91% 8.5% 0.06%

Silicate asteroid

IMPACTS Small rocks can make a big bang: The 2013 Chelyabinsk meteor was 65 feet across, but the shock wave Sudbury crater shattered enough glass to injure over 1,000 people. But don’t panic. Large impacts happen about once every million years. South Africa’s nearly 200-mile-wide Vredefort crater places first among Earth’s largest confirmed impacts (right).

Silicate and metal asteroids are somewhat uncommon space rocks — most others are mainly carbon. But rare metals, a tiny slice of the compositions below, make them lucrative mining targets.

Kara crater

Popigai crater

Manicouagan crater Lake Tai crater Chicxulub crater

Morokweng crater

Vredefort crater

Warburton crater

Acraman crater

OOxygen OIron OSilicon OMagnesium OAluminum ONickel OCalcium

36% 26% 18% 14% 1.5% 1.4% 1.3%

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EVERYTHING

Ancient DNA

KNOWING

The lure and limitations of a coded past.

WORTH

BY BRIDGET ALEX

The genetic record is “like a lost library . . . ancestors of some living humans, contributing and we’re just starting to learn the language of genes beneficial in cold environments and at all those books that we have uncovered,” says high altitudes. Johannes Krause, director of archaeogenetics A decade ago, these discoveries were not at the Max Planck Institute for the possible; geneticists could only read Science of Human History in short stretches of ancient genomes. Jena, Germany. Consequently, studies focused For anthropologists, either on particular genes or ancient human DNA on narrow portions of DNA: (aDNA) provides insights the male Y-chromosome or that could not be gleaned maternally inherited code from fossils or artifacts. It’s called mitochondrial DNA. already settled some major These short sequences do not debates, including whether reflect an individual’s complete modern humans interacted ancestry. For that, researchers Quagga with Neanderthals. Ancient need DNA from across the full genomes show definitively that our genome. Obtaining it from living ancestors not only met, but mated with humans is not difficult, but it’s a formidable Neanderthals — multiple times — between challenge to extract and sequence genome-wide 40,000 and 100,000 years ago. aDNA, which can degrade into fragments, In 2015, aDNA confirmed that Kennewick undergo chemical reactions that change its Man, an 8,000-year-old skeleton found in code, and be contaminated by modern DNA. Washington state in 1996, was genetically With the recent development of specialized closest to Native Americans. The revelation methods for genome-wide analysis of aDNA, ended a 20-year legal battle and allowed tribes “the power of archaeogenetics has really been to rebury the bones. unleashed,” says Krause. Ancient DNA has also brought Now encompassing a half-million years and surprises. In 2010, the genome hundreds of individuals, ancient DNA studies of a pinky bone from Siberia are revising our understanding of major events, revealed the existence of such as the origins and spread of agriculture. Denisovans, a previously Because aDNA can be used to track the unknown type of human evolution of diseases and human resistance to that lived around the them over time, it’s also valuable to medical time of Neanderthals. research. And researchers are already working Denisovan aDNA on identifying the genes unique to modern also shows they humans — at the most basic level, what unites interbred with the and defines our species.

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DNA: ORANGE DEER/SHUTTERSTOCK. QUAGGA: FLORILEGIUS/ALAMY STOCK PHOTO

In 1984, geneticists recovered 229 base pairs of genetic code from a quagga, a subspecies of zebra extinct since the late 1800s. The achievement proved DNA could survive in dead things and spurred a new field of science: paleogenetics. Today, technological advances allow scientists to read billions of letters from the genomes of ancient humans and other organisms, transforming our view of history and evolution.

Decoding aDNA 101 2. DNA soup: Despite cleaning, the extract is a soup of DNA from the sample and contaminated material, mostly microbes from soil where the remains were buried. Researchers add molecular tags that will later work like barcodes, selectively binding to DNA to inventory and find particular sequences.

1. Extraction: In a sterile lab, bones and other surviving tissues are cleaned, crushed into powder and dissolved with chemicals that isolate short DNA strands.

Ancient human DNA

Modern human DNA Microbial DNA

3. Copies: To read the DNA quickly and accurately, computers must analyze millions of copies simultaneously. Geneticists make these copies by heating double-stranded DNA, causing it to separate; enzymes then build new double-strands from each half. Repeating the procedure makes two strands into four, then four into eight, and so forth, until millions of strands have identical DNA code and tags. Because human genomes are over 99 percent identical, researchers often selectively copy only the parts that differ.

4. Sequencing: In the final round of copying, geneticists chemically color the different nucleotide bases — better known by their letters A, T, C and G. Computers then read the code based on the order in which the colors appear, analyzing all the identical strands with matching tags at the same time to weed out any errors.

Heat

5. Authentication: Researchers use a number of clues to discard contaminants in the ancient code: For example, aDNA strands are usually shorter than 100 letters, with predictable degradation patterns. Ancient hominin reads T CC A A A GC A T C A C C A C C A A T A A C T C A T C A T T CCC T A G T G A A T GG A C A G T C

Ancient DNA fragments Rejected pattern

A T CGGG A C T C A GG

CYNTHIA SCHROEDER

GG A C T C A GGC A C T T G A T T A A GGC A C T T G A T T A C C T

Ancient hominin reads

T T A C C T C A A G A T C C T A C GG

6. Alignment: The short strands that have been read need to be arranged into their proper positions across the full genome. Software lines them up based on overlapping stretches of code and comparisons with previously sequenced reference genomes.

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KNOWING

Ancient DNA

Take It to the Limit Don’t get your hopes up for dino DNA. Studies conducted in the 1990s, reporting genetic code from fossils over 50 million years old, have since been rejected as cases of contamination. Most aDNA has come from samples younger than 50,000 years, and from cold climates. Although paleogenetics is advancing technologically, it will always be limited by preservation: Researchers can’t extract DNA from specimens that no longer have any. When organisms die, their DNA decomposes. How long this takes depends on factors like temperature, burial conditions and the number of microbes making a meal of it. Calculations predict that in the optimal conditions — very cold ones — DNA could survive around 1 million years. To date, the title for oldest complete genome belongs to a horse unearthed from frozen ground in Yukon, Canada, and dated to be 560,000 to 780,000 years old. The oldest DNA from a member of our Homo genus is a fragment of genetic code from 430,000-year-old Neanderthal ancestors found in Spain’s Sima de los Huesos cave, which stays at a cool 50 degrees Fahrenheit. Geneticists are starting to have success in warmer places, which is a priority because most of human evolution occurred in Africa. Recently, they discovered that DNA preserves best — with up to 100 times higher recovery rates — in the petrous bone. Samples of this tiny, dense part of the skull from places such as the Middle East have yielded aDNA that’s up to 12,000 years old.

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Ancient DNA Atlas The first big discoveries in paleogenetics came from chance specimens with well-preserved aDNA. Researchers learned whatever they could from the available sequences. With today’s aDNA capture methods, geneticists can analyze hundreds of ancient genomes to answer specific questions. The emerging genetic history spans the globe from 430,000 years ago to today, representing both individuals and entire populations.

Earliest American Genome (Montana 12,600 years ago) In 2014, researchers recovered the genome of Anzick-1, an infant buried with Clovis tools, artifacts from the first widespread culture in the Americas. The results confirm that Native Americans mostly descend from Siberians who migrated several thousand years before Anzick lived.

Seal Tuberculosis (Peru 1,000 years ago) Tuberculosis in the Americas is thought to have arrived with European colonists, although earlier indigenous skeletons show signs of the disease. A 2014 study found tuberculosis bacteria DNA in 1,000-year-old Peruvian bones; in a surprise twist, it was not the European strain, but one likely contracted from seals.

MAP: EKLER/SHUTTERSTOCK; CLOVIS TOOLS: SARAH ANZICK; FUR SEAL: CYRIL RUOSO/NATURE PICTURE LIBRARY

EVERYTHING

WORTH

CLOCKWISE FROM TOP: JAMES CAVALLINI/SCIENCE SOURCE; MAX PLANCK INSTITUTE FOR EVOLUTIONARY ANTHROPOLOGY; JOSÉ ANTONIO PEÑAS/SCIENCE SOURCE; MAX PLANCK/SVANTE PÄÄBO; JAVIER TRUEBA/MADRID SCIENTIFIC FILMS/SCIENCE SOURCE

Before the Black Death (Eurasia 3,000-5,000 years ago) In 2015, geneticists discovered aDNA from plague-causing Yersina pestis bacteria in the teeth of Bronze Age Eurasians, revealing that less-contagious strains infected people millennia before historically documented pandemics. The bubonic types responsible for the medieval Black Death and recent outbreaks emerged about 3,000 years ago from a mutation that made Y. pestis flea-borne.

Oldest Homo DNA (Spain 430,000 years ago) Researchers in 2016 salvaged about 50,000 base pairs of genetic code from fossils excavated years before in the Sima de los Huesos cave. The aDNA confirms what many archaeologists have long believed: The Sima hominins were Neanderthal ancestors.

Neanderthal Great- . . . Grandson (Romania 40,000 years ago) Oase 1, the jawbone of a modern human found in 2002, contained over 99 percent contaminant DNA. But in 2015 researchers sequenced enough authentic code to show that the man had a Neanderthal ancestor a mere four to six generations back.

Ice Age Immigrants (Eurasia 7,000-45,000 years ago) aDNA from 51 individuals reveals the earliest modern humans to reach Europe went extinct; those arriving in subsequent waves, starting 37,000 years ago, left descendants who remain to this day. There may also have been a migration of Near Easterners into Europe roughly 14,000 years ago, detected for the first time by aDNA analysis in 2016.

Denisova Cave (Altai Mountains 50,000-100,000 years ago) Samples of aDNA from one finger fragment and three teeth found in Siberia revealed Denisovans, a newly discovered type of extinct human. The same site also yielded a toe bone, which produced the highest-quality Neanderthal genome sequenced so far.

First Farmers (Middle East and Europe 3,000-14,000 years ago) Analyses of hundreds of genomes show how early Middle Eastern farmers spread to Europe, mixed with hunter-gatherers and adapted to agricultural diets, including through a lactase gene mutation that allowed people to drink milk after childhood.

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EVERYTHING

Marijuana

KNOWING

The blunt truth.

WORTH

BY LACY SCHLEY

Humans have used marijuana, or Cannabis sativa, for thousands of years, for religious purposes, medicinal remedies or simply getting high. These days, 1 in 8 Americans ingest or smoke marijuana, and the drug faces renewed scrutiny as more states wrestle with legalization. While the legislative battles rage on, scientists continue to study the effects this plant can have on us, therapeutic and otherwise. But the work isn’t easy. The U.S. government hasn’t legalized marijuana and still classifies it as a Schedule I drug — with high potential for abuse, no accepted medical use and no safe use under medical supervision. To study it, experts must secure samples with a Drug Enforcement Administration stamp of approval. That makes for some serious restrictions for researchers, though they’ve made some headway.

Cannabinoids Any chemical that interacts with the cannabinoid systems in the body; these can include cannabinoids that come from the plant, from the body or from synthetic variations. Phytocannabinoids Cannabinoids that come naturally from the cannabis plant. Endocannabinoids Cannabinoids the body makes on its own.

The Body’s Cannabinoids In the 1990s, researchers realized humans can produce their own cannabinoids Endocannabinoids through the body’s endocannabinoid system (ECS). The ECS is a complex chemical Receptors signaling system that has two main receptors Receptors located in many Neurotransmitters areas of the body.

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The Big Players C. sativa has hundreds of chemical compounds, from fatty acids to the terpenes that give it its distinct smell. But the most studied are cannabinoids. Below are the most common cannabinoid subclasses and their general impact on the body. O Cannabidiols (CBD): Painkiller, antiinflammatory, antioxidant, anxiety reducer, antipsychotic, suppresses muscle spasms. O Tetrahydrocannabinols (THC): Painkiller, antiinflammatory, antioxidant, euphoriant, suppresses nausea and vomiting. O Cannabigerols (CBG): Painkiller, antiinflammatory, antibiotic, antifungal. O Cannabichromenes (CBC): Painkiller, antiinflammatory, antibiotic, antifungal. O Cannabinols and cannabinodiols (CBN, CBND): Anti-inflammatory, antibiotic, sedative, anticonvulsant. O Others: Includes cannabicyclols (CBL), cannabielsoins (CBE), cannabitriols (CBT) and other miscellaneous types.

LEFT: JAY SMITH. RIGHT: DREAMWAVES/SHUTTERSTOCK

Know Your Lingo

Good for What Ails You

There’s Always a Downside

Scores of studies have found that cannabinoids can help with specific disorders and diseases, but not all studies are created equal. Many of them use different doses, administer those doses differently and can use combinations of cannabinoids with different ratios. So a lot of the results are hard to compare and don’t always agree. Below are some disorders and diseases where cannabinoids seem medically helpful.

PSYCHIATRIC/ NEUROLOGICAL DISORDERS O Anxiety and panic disorders CBD reduces symptoms. O Schizophrenia CBD reduces psychotic symptoms. O Parkinson’s CBD alleviates psychotic symptoms and some issues with motor control.

O O Heart function THC and CBD combination relaxes some arteries.

Plenty of promising research shows the pros of marijuana use, but also some serious cons.

OO Sleep disorders THC improves sleep quality and quantity for some people; CBD increases alertness.

O O O O O Antiinflammatory All of the most common cannabinoids relieve swelling.

O O O O Pain Most of the common cannabinoids relieve pain.

OTHER DISORDERS

Brain function and mental health: Long-term use could lead to panic disorders and psychosis. If you’re a longtime user who started lighting up in your teens, your hazy days could predispose you to depression. To top it off, repeated exposure to THC can have a negative effect on areas of your brain that deal with forming memories, like the hippocampus and prefrontal cortex. Heart health: Even minor use of cannabis can cause your heartbeat to ramp up, and mess with your blood pressure levels and blood flow. (Research has shown both increases and decreases in blood pressure.) Sexual and reproductive health: Men, if you’re looking for some action, best mind your marijuana habits: Chronic use can lead to erectile dysfunction and a decrease in overall sexual functioning (pleasure, orgasm, desire and arousal). And if you want to start a family, there’s more bad news. THC has been shown to restrict sperm mobility and its ability to fuse with eggs. Very heavy male users (who smoke eight or more joints daily) even risk reducing their sperm count. As for women, researchers have yet to really investigate how cannabis impacts them between the sheets, and studies looking at human female fertility have been inconclusive.

OO MS

COOLGRAPHIC/SHUTTERSTOCK

ODigestion complications THC eases chemorelated nausea and vomiting, helps improve symptoms of irritable bowel syndrome.

OO Immune system complications THC and CBD combination alters growth and function of certain immune cells.

THC alleviates MS-related pain; THC and CBD combination reduces muscle spasms. O AIDS THC increases appetite and helps with weight gain. O Epilepsy CBD reduces convulsions. O O Cancer THC and CBD combination reduces chemorelated nausea and vomiting, manages pain, stimulates appetite.

Dependence: You can’t overdose on cannabis, but you can develop a dependence. Up to 17 million people globally meet the official classification when it comes to cannabis. Hallmarks include inability to lessen intake, using even if you’ve had physical or psychological issues related to cannabis and spending more time than you’d like seeking to buy the drug and recovering from its effects. If you’re trying to kick the habit, expect symptoms such as mood swings, a lack of appetite and trouble sleeping. Further reading: Handbook of Cannabis, edited by Roger G. Pertwee. Stoned: A Doctor’s Case for Medical Marijuana, by David Casarett.

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EVERYTHING

Alien Contact

KNOWING

Hey, it could happen!

WORTH

BY SARAH SCOLES

The search for extraterrestrial intelligence (SETI) has been going for more than 50 years, with ever more sophisticated detection systems and creative ideas about how E.T. might come calling. Astronomers haven’t heard anything yet, but perhaps it’s only a matter of time. Check out what they’ve been looking for, how they would know if they found it and what the aftermath might be.

How to Listen The universe emits many signals of its own. Black holes send out bursts of radio waves, X-rays and gamma rays. The dusty disks of forming planetary systems shine in infrared waves. Scientists must separate those so-called dumb signals from the smart signals that might come from extraterrestrials. Because of that necessary sifting, they assume that aliens would try to make their messages look different from the natural pings of the universe. In general, astronomers look for two hallmarks of technology.

INTENSITY

Synthetic narrowband signal

Natural narrowband signal

Frequency compression: Narrowband signals come in on a small range of frequencies, like an individual radio station. Broadband signals spread across a wider range, like a broadcast that contains the whole FM band at once. Natural objects can only make signals so skinny, so if scientists see one that covers a tiny range of frequencies — like a laser or a satellite ping — they know it had to come from technology. 

Noise

Broadband signal

Time compression: Scientists look for signals that last only for a flash and repeat, perhaps in a pattern that looks purposeful.

FREQUENCY

BONUS! Almost-but-not-quite-natural-looking: Astronomers also keep their telescopes’ eyes out for anything that looks nearly natural. When researchers discovered fast radio bursts — superquick bursts that release at least as much energy in milliseconds as the sun does in a month — they threw around “aliens” as a (dim) possible explanation. And when astronomers discovered a star in 2015 whose light seems to occasionally get blocked by something big, one researcher proposed it was an alien megastructure. We still aren’t sure what causes either phenomenon, but scientists are studying them as natural emissions from the universe.

You wouldn’t dip a glass in the ocean, come up with no fish inside and conclude, “No fish exist.” Astronomer Jill Tarter often says that’s where humans are with SETI. To fill enough glasses to get a good sense, researchers want to look at 1 million stars within 1,000 light-years of Earth and scan all the frequencies between 1 and 10 gigahertz. When they’ve done that, maybe they’ll have caught a fish or two — or will at least be able to say more about how many swim in the cosmic sea. Here’s how close they’ve gotten, proportionally, to that goal.

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99.959% How much searching astronomers still have to do to “cover” 1 million stars.

0.041% How much of that search they have completed, for all radio SETI projects.

LEFT: WIREMAN/SHUTTERSTOCK. RIGHT: JAY SMITH

Are We There Yet?

An artist’s rendering of the TRAPPIST-1 system

Searches Past and Present 1960 Astronomer Frank Drake performs the first modern SETI experiment, called Project Ozma (after a Wizard of Oz character). With an 85-foot radio telescope in Green Bank, W.Va., he looks at two sunlike stars for signs of alien technology. 1961 A small SETI conference takes place in Green Bank, at which Drake presents what’s now called the Drake Equation, which scientists use to estimate how many extraterrestrial civilizations may exist in our galaxy. 1973 Ohio State University undertakes a SETI program with its Big Ear Observatory. 1979 The University of California, Berkeley, begins a long-lived project called SERENDIP — the Search for Extraterrestrial Radio from Nearby Developed Populations — at Hat Creek Observatory in Northern California. 1983 At Harvard University, astronomer Paul Horowitz launches Project Sentinel, using an 84-foot radio telescope.

Our Best Bets Just as you wouldn’t bird-watch in interior Antarctica, you wouldn’t search for aliens in inhospitable environments. Astronomers have discovered thousands of planets, but only a few so far meet our basic requirements for possibly hosting life: being rocky and in the habitable zones around their stars (where water can stay liquid). Here are a few potentially life-friendly star systems where astronomers will aim their alien-seeking telescopes.

PROXIMA CENTAURI

1992 NASA’s SETI project, now the High Resolution Microwave Survey (HRMS), turns paperwork and plans into a physical project at Goldstone Observatory in California and the Arecibo radio telescope in Puerto Rico. 1993 Just a year after its start, HRMS ends when Congress cancels its funding.

The star system closest to our sun has a planet — Proxima b — similar to Earth’s mass. No one knows if it has any water, but it’s just 4 light-years away, so maybe we could find out in person someday.

1995 The private SETI Institute raises philanthropic funds and starts Project Phoenix, a reincarnated version of HRMS.

WOLF 1061

1995 Horowitz continues his SETI work at Harvard with the Billion-Channel Extraterrestrial Assay (BETA).

The second planet in this star’s solar system is the next-closest Earth-ish-sized planet in a habitable zone, after Proxima b. It’s just 14 light-years from where you’re sitting right now.

GJ 667 A mere 22 light-years away, this solar system has three super-Earth planets — between Earth’s and Uranus’ mass — in the habitable zone. And in the hunt for extraterrestrial life, every possibility counts.

TRAPPIST-1 Some 39 light-years away, this sun has three potentially rocky planets in its habitable zone and — bonus — four additional rocky planets. That’s seven Earth-ish-sized planets in one spot!

KEPLER 186 NASA/JPL-CALTECH

1988 NASA endorses its SETI studies, and scientists begin building the instruments they need to perform a search.

About 561 light-years away, the fifth planet discovered in this dwarf-star system circles its star’s habitable zone. The planet was the first astronomers found with a size similar to Earth’s.

1999 Berkeley launches the citizen science project SETI@home, which lets your computer, in its downtime, dip into SERENDIP data. 2005 The SETI Institute begins building a telescope dedicated to searches for aliens. 2015 METI (Messaging Extraterrestrial Intelligence) International begins an optical SETI program at the Boquete Observatory in Panama. 2016 The $100 million Breakthrough Listen project, sponsored by Russian magnate Yuri Milner, begins a 10-year search that includes both radio and optical strategies.

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EVERYTHING

WORTH

KNOWING

Alien Contact

Should We Transmit a Message?

So You Think You’ve Discovered Aliens

In addition to listening for E.T.’s phone calls, we could also try catching his attention. But scientists aren’t sure whether that’s a great idea.

Here’s what to do when a candidate signal is detected (informally called the First SETI Protocol, formally called “Declaration of Principles Concerning the Conduct of the Search for Extraterrestrial Intelligence”):

SUPER PRO Douglas Vakoch President, METI (Messaging Extraterrestrial Intelligence) International

“One of the assumptions we typically make is that if there are civilizations out there, they will take the initiative in letting us know they’re there. But if they do what we’re doing, we’ll never make contact. I want to send an intentional message letting other civilizations know that we want to engage in the conversation.”

PING! A candidate SETI signal arrives at your telescope.

DO A DOUBLE-TAKE. Look at the same spot again. Does the signal show up?

YES

NO

PRO Seth Shostak Senior astronomer, Center for SETI Research at the SETI Institute

“I’m in the pro-transmitting camp!” says Shostak. In one position paper, he explains that if an alien society wanted to destroy us, keeping quiet wouldn’t keep us hidden anyway: “Any putative extraterrestrials who are in possession of technology that would allow them to threaten our world will also be able to detect [our] unintentional leakage signals.”

ANTI Jill Tarter

Does it come from the heavens or the Earth?

HEAVENS

EARTH

GAME OVER. E.T. didn’t phone.

REPEAT. Gotta make sure of these things.

Call up your telescope operator friends. Do they see the same suspicious signal coming from space?

NO

Former director, Center for SETI Research at the SETI Institute

SUPER ANTI Stephen Hawking Physicist and mathematician, University of Cambridge; author of A Brief History of Time

Hawking has warned that broadcasting our existence could end with an unpleasant visit from highly evolved aliens. “Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach,” he said in 2010. The history of our own species backs him up.

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YES

Call even more friends, and have them call friends (an alien phone tree!) to monitor the signal ’round the clock and ’round the globe.

Call everyone involved with your project and scream joyfully.

Tell everybody in the whole world.

Hang up the phone.

Put your data online, because aliens are for everyone.

(Presumably) build the spaceship from designs they sent you.

FROM TOP: SETH SHOSTAK (3); REX FEATURES/AP IMAGES

“We aren’t grown-up enough to take on 10,000-year projects, and transmitting for a moment or a year makes no sense. Transmission is in our future, assuming we make it to the ‘advanced technological civilization’ status.”

Tomorrow’s SETI Dyson sphere searches: Energy-hungry civilizations might put Dyson spheres around their stars. These structures collect visible light and transform it into infrared radiation (heat energy) that would show up as unexpected excesses in astronomers’ data. Broadband searches: A broadband message, spread across many frequencies, can encode tons more information than the more presumably typical narrowband one. But the message would then be spread thinner and harder to pick up. Sophisticated algorithms are learning to sort through data to find these complex missives, just in case. Optical SETI: The search for visible-light signals from extraterrestrials is just beginning, as the technology that detects the light inside telescopes becomes more powerful, affordable and able to detect faster flashes. And who knows? Maybe aliens like lasers.

Dyson sphere visualization

Cinematic SETI Sometimes, fictional film people meet extraterrestrial beings. When the encounters are good, they are very, very good. But when they are bad, they are horrid — and leave humans destabilized or dead. Here, we’ve ranked some of the most famous first-contact movies according to how naughty or nice the aliens are, as well as how realistic they, their technology and Earth’s response are.

BENEVOLENT

Contact Arrival

E.T. the ExtraTerrestrial

Close Encounters of the Third Kind

REALISTIC

2001: A Space Odyssey

Signs

OUT THERE

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How we might hunt alien signals in the future.

The Abyss John Carpenter’s The Thing

District 9 Independence Day

War of the Worlds

Alien Star Trek: First Contact

AGGRESSIVE

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Autism Spectrum Disorder Many questions, few answers. BY MARK BARNA

Social interaction Avoids eye contact, prefers to be alone, avoids physical contact, irritable, anxious, might be interested in people but doesn’t know how to talk or relate to them. Communication Difficulty expressing needs with typical words or gestures, doesn’t look at objects when someone points to those objects. Repetitive behaviors Obsessive interest in limited areas, adherence to routine, repeats particular movements such as hand flapping or rocking back and forth. Sensory overload Unusual reactions or sensitivity to light, noise, smells, tastes and textures, such as the roughness of clothing.

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A NEW SPECTRUM Autism was once separate from other developmental complications such as Asperger’s syndrome, pervasive developmental disorders (PDD) and childhood disintegrative disorder. But in 2013, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, the standard medical reference for mental disorders, merged Asperger’s, PDD and the old definition of autism and created the catchall term autism spectrum disorder. Many experts argued the new label would be more helpful; despite including a broader range of symptoms, the revised definition is worded more clearly and thus is more specific. But in practice, other medical professionals and families have criticized the change. Although the evidence isn’t cut and dried, there are several anecdotal accounts of some high-functioning patients — who met the old, more vague criteria but not the updated one — losing medical services associated with autism.

The ASD Rainbow The autism spectrum describes people with a wide range of developmental disorders. Many who were high-functioning used to be diagnosed separately as only having PDD or Asperger’s. (Most people with autism are diagnosed as children.) Now, medical experts use a series of levels to figure out where patients lie on the spectrum.

AUTISM SPECTRUM DISORDER

HIGH-FUNCTIONING AUTISM LEVEL 1 Needs support Patient’s social and communication skills and repetitive behaviors are only noticeable without support.

AUTISM

SEVERE AUTISM

LEVEL 2 Needs substantial support Patient’s social and communication skills and repetitive behaviors are still obvious to the casual observer, even with support in place.

LEVEL 3 Needs very substantial support Patient’s social and communication skills and repetitive behaviors severely impair daily life.

IUNEWIND/SHUTTERSTOCK

Signs and Symptoms of Autism Spectrum Disorder

There is no cure. The causes are only partially understood. And treatments are limited to tackling symptoms, not the condition itself. One in 68 school-age kids in the U.S. have autism spectrum disorder (ASD), a range of developmental conditions usually marked by social, behavioral and communication issues. While researchers are making progress in figuring out ASD’s causes and developing better treatments, there’s still a long way to go.

RISK FACTORS Only decades ago, experts thought a lack of parental affection was a major cause of autism — a notion that’s since been debunked. And people who should have been diagnosed with autism were often misdiagnosed with schizophrenia or other mental conditions and institutionalized. Today, ASD is widely viewed as the result of genetic and certain environmental factors that influence early brain development.

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Genetic “Twin studies are one of the most important pieces of evidence for genes being involved [in autism],” says Abha Gupta, a pediatrician who also researches the genetics and neurobiology of ASD at Yale School of Medicine. Identical twins share nearly 100 percent of their genes, while fraternal twins share about 50 percent. So if identical twins have a disorder, it’s strong evidence for a genetic cause. Since the 1970s, these sorts of studies have revealed that both identical twins are more likely to have autism than both fraternal twins. A recent study has shown that, if one identical twin has ASD, the likelihood of the other twin having it is between 77 and 99 percent; for fraternal twins, the likelihood is 22 to 65 percent. Hundreds of genes are linked to ASD, making it tough to research. Currently, many researchers agree that 60 to 70 genes are related to the syndrome, but those genes account for no more than 20 percent of the cases — the best medicine can do so far. Although ASD is heritable, children with no family history of the disorder can still develop it through genetic mutations. And those who have kids after they’re 35 years old are also more likely to have children with autism.

No Link Between Vaccinations and Autism

Environmental Research on environmental factors is ongoing; some experts believe these factors can influence an infant’s odds of having ASD if they’re exposed to certain things during the early stages of fetal brain development. So far, the only generally accepted risk factors are related to maternal health during pregnancy, such as inflammation stemming from an infection. Other possible risk factors: iPremature birth iAir pollution iWater pollution iPesticides

A Century of Autism 1911 Swiss psychiatrist Eugen Bleuler coins the word autism — from the Greek autos, meaning “self” — to describe extreme self-obsessiveness

and anti-social behavior in children. 1943 Leo Kanner at Johns Hopkins Hospital publishes the first case studies of autism as a medical condition.

1944 Austrian scientist Hans Asperger describes a disorder called Asperger’s syndrome, which, in older diagnostic criteria, had similar but milder symptoms than autism.

In 1998, British gastroenterologist Andrew Wakefield made headlines when he argued there was a possible link between autism and the childhood vaccination for measles, mumps and rubella. His paper, published in the British medical journal The Lancet, resulted in many parents in Britain and the United States not vaccinating their children, increasing their chances of contracting one of the potentially deadly diseases. But scientists found flaws in Wakefield’s work. Ten of the paper’s 12 co-authors denounced its findings in 2007. Three years later, The Lancet retracted the paper, and the British Medical Council revoked Wakefield’s medical license. Over the years, many robust studies have found no causal link between autism and childhood vaccinations. Instead, most experts say Wakefield’s work set back autism research and created unwarranted fear about childhood vaccinations that lingers today.

1964 Bernard Rimland publishes the book Infantile Autism: The Syndrome and Its Implications, which asserts autism has a neurological cause rather than a psychological one.

1968 Donald Baer, Montrose Wolf and Todd Risley publish the defining paper on applied behavior analysis, a behavioral therapy that focuses on developing social skills and lessening repetitive behavior.

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Autism Spectrum Disorder

TREATMENTS Health professionals can reliably diagnose ASD in kids as young as 16 months old. They rely on behavioral observations, medical screenings and a child’s developmental history for their diagnosis. Then, families and experts work together to come up with a tailored treatment plan that can include any combination of the following therapies below.

Medications

Behavioral Therapies

Antipsychotic, anti-anxiety and stimulant medications can, to some degree, control ASD symptoms such as repetitive behaviors, anxiety and irritability. But they also can cause side effects and don’t alleviate anti-social behavior, says Darold Treffert, an autism expert who runs a clinic for children with developmental disorders in Fond du Lac, Wis. “The time will come when we can do a genetic profile to determine the kinds of medications that would be helpful to a patient with autism,” Treffert says.

Many behavioral therapies exist, but the most common is applied behavior analysis, or ABA, established in 1968 by Donald Baer, Montrose Wolf and Todd Risley. In ABA sessions, therapists work with children to modify their behavior and develop social skills with a combination of techniques, like positive reinforcement and chaining — breaking a skill down into small chunks so it’s easier to learn. Until the 2000s, these programs tended to be cookie-cutter and rigid, Treffert says. Recently, therapists have moved on to behavioral approaches, often variations or modifications of ABA, that focus more on children’s strengths and interests rather than behaviors that negatively impact their life. For instance, one of Treffert’s patients is a 3-year-old boy, an above-average reader fascinated by the solar system. So his therapy team uses books about astronomy to engage with him, which makes it easier to work on his behaviors. Therapists now also focus more on their personal relationship with their patients. And therapies begin earlier — at age 2 or 3 rather than 7 or 8. Still, behavioral therapies remain controversial. The U.S. Department of Education has found that the ABA model has “no discernible effects on communication and language skills, social and emotional development or functional abilities,” says Julia Bascom, executive director of the Autistic Self Advocacy Network (ASAN). Because of this, Bascom says ASAN recommends programs and services aimed at helping children with autism build skills that can enhance their quality of life, like speech therapy and occupational therapy, which teach specific daily living skills.

Autism in the U.S. 44%

Children on the spectrum with average or above-average intellect (IQ higher than 85).

10%

Children who also are savants, or patients showing remarkable memory and skill in a specific area, such as music.

20%

Children with enlarged brains as infants and toddlers.

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1980 The third edition of the Diagnostic and Statistical Manual of Mental Disorders includes autism for the first time. 1998 Andrew Wakefield, a British gastroenterologist, and 12 other

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Complementary Therapies Treatments aside from traditional behavioral programs may reduce a patient’s anxiety, which can also lessen some repetitive behaviors and help in social situations. The most popular are: iPet interaction iFine art and music participation iDietary programs (vitamin/mineral supplements, diets free of yeast, gluten or artificial additives)

researchers publish a now-retracted paper in The Lancet linking autism and childhood vaccinations. 2003 Researchers find the first genes linked to autism, providing clues that could lead to better treatments.

2003 The Autism Diagnostic InterviewRevised, an interview process that helps doctors and specialists diagnose the disorder, is introduced. 2010 The Lancet retracts Wakefield’s paper, and the British

Medical Council revokes his medical license. No other research has ever suggested such a link. 2013 The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders merges classic

autism, Asperger’s syndrome, childhood disintegrative disorder and PDD under the ASD umbrella.

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1 in 42 Boys 1 in 189 Girls

AUTISM AND THE BRAIN Years of studies in children on the autism spectrum suggest they have an increased brain volume that may correlate with the severity of their symptoms. But the brain returns to normal size, or smaller, by the time a child is an adolescent. Studies have also indicated various brain regions as playing a role in ASD, and that these areas may fluctuate in size compared with brains of kids without ASD, but the work is still inconclusive.

Pars opercularis Involved in language comprehension.

Superior temporal sulcus Involved in perception of emotions and facial cues; shown to have structural abnormalities.

Prefrontal cortex (includes the cerebral cortex) Responsible for cognitive and social learning; may cause faulty connections to other parts of the brain.

Corpus callosum Connects the right and left brain hemispheres; onethird of people born without this structure are on the spectrum.

Caudate nucleus Stores and processes memories, acting as a feedback mechanism to regulate future behavior.

CLOCKWISE FROM LEFT: SCIEPRO/GETTY IMAGES; EVAN OTO/SCIENCE SOURCE; ALEX MIT/SHUTTERSTOCK

Amygdala Regulates emotions, especially those for survival, such as fear and aggression; there’s conflicting evidence that neurons in this brain area can be overor underconnected.

Cerebellum Controls motor skills, including muscles for speech.

Hippocampus Deals with memory and learning; in mouse models, it’s sometimes enlarged.

Brain size About 20 percent of children between 18 months and 4 years old with ASD have brains 5 to 10 percent larger than average. Some scientists attribute this to an overload of nerve-fiber growth during prenatal development.

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Ice

KNOWING

It’s everywhere!

WORTH

BY SIDNEY PERKOWITZ

We typically encounter ice as cubes floating in a glass of something nice to drink. But more than just a party staple, ice is a significant part of our planet and the universe — a fundamental substance that deeply affects us, and may even be connected to the origins of life. Talk about refreshing!

No-Tech, Low-Tech and High-Tech

Americans love ice. We make desserts out of it, put it in drinks and expect motels to provide it by the bucketful. But before ice-making technology, it was a precious commodity laboriously harvested from nature. In the early 19th century, American entrepreneur Frederic Tudor began shipping ice cut from New England ponds to warm climates like the West Indies. He eventually became the “Ice King,” selling thousands of tons of ice throughout the U.S. for iceboxes, which preserved food. Natural ice remained profitable until a century ago with the arrival of electric refrigerators, which exploited the cooling properties of evaporating liquids. Those white boxes with clumsy cooling units have evolved into sleek stainless steel models, but we still harvest ice. High-end drinkers want premium, artisanal ice in their craft cocktails — perfectly clear, oversized cubes that look good and supposedly melt slowly to avoid dilution. While these can be created in-house, it’s a time-consuming process, so specialty companies now provide this elaborate ice. The cubes are hand-cut from big blocks of filtered water gradually frozen in special units for days, a process that eliminates the air bubbles that produce cloudiness. The cost? A whopping $1 each. The Ice King would be green with envy.

Workers harvest ice from a frozen lake in the northern U.S. in the 1930s.

Artisanal ice is cut with a band saw and shaped into clear cubes without bubbles for drinks at the Half Step bar in Austin, Texas.

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EARTH . . .

FROM TOP: KENNETH LIBBRECHT/SCIENCE SOURCE (3); UMARAZAK/SHUTTERSTOCK; GISELA PREUSS VIA THE EUROPEAN GEOSCIENCES UNION; ALISON MACKEY/DISCOVER AFTER CANADIAN GEODETIC SURVEY/NATURAL RESOURCES CANADA

A Most Complicated Mineral Ice is not just the solid form of water. By definition, natural ice is a mineral, like quartz: a naturally occurring inorganic solid with an ordered atomic structure. Or rather, structures. It appears in at least 18 different crystalline forms, plus amorphous forms where the atoms are randomly arranged. The variety that cools our drinks, hexagonal ice or Ih, is the most common type, but it’s also quite unusual. Unlike most solids, its frozen state is less dense than its liquid state, thanks to the hexagonal atomic geometry. That means frozen water floats on liquid water — not the case for almost any other substance. The geometry is the reason icebergs float, and helps explain why bodies of water don’t freeze solid from the bottom up, allowing aquatic life to survive winters. Common ice also appears as snowflakes, which take on Atomic structure hexagonal forms in atmospheric water vapor. Less well known of hexagonal ice is hair ice, which grows in fine filaments on wood infested with a specific fungus. Other exotic ice structures are made in the lab. Researchers recently found that squeezing room-temperature water between atom-thick sheets of carbon locks the water molecules into a twodimensional square array to form a new kind of ice.

Kurt Vonnegut’s novel Cat’s Cradle featured Ice-Nine, a fictional version of ice that would instantly crystallize all water, potentially dooming the world. While there really is an “icenine,” it forms only under high pressure and low temperature, and does not “lock up” all water.

Hair ice

Reshaping the World Earth’s massive ice stores are melting, thanks in part to global warming, and we’re seeing the effects on our planet. One of the biggest concerns is the accompanying rise in average global sea level — estimated at 3 to 6 feet by 2100. But other problems pop up with some 400 billion tons of Greenland and Antarctic ice turning into water each year since 2011. First, there’s something called post-glacial rebound. Ice piled onto a landmass presses it down into the squishy mantle layer below Earth’s crust. As our world warms, the formerly icy areas rebound, literally raising the land up. That’s one reason for the varying sea level rises along different coasts. Also, the weight of all that ice had slightly flattened the whole planet. (A single glacier can weigh millions of tons.) Rising temperatures caused it to start becoming spherical again. This influenced Earth’s rotation, akin to an ice skater jutting out her arms to spin slower, contributing toward a lengthening of the day by milliseconds over the past 2,500 years. It also alters the planet’s axial tilt: The North Pole had been steadily wandering toward Canada, but researchers recently realized that the current ice melt has jolted it on a new course toward the United Kingdom, at an accelerated rate of 7 inches a year since 2000. Astronomers’ stellar observations and your phone’s GPS program have to take this effect into account.

POST-GLACIAL REBOUND

Flexing upward

Ice

Loaded crust “sinks”

Mantle flows outward

Global sea level rising Collapsing

Crust rebounding Mantle flows back

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Ice

. . . AND BEYOND In 2015, NASA’s New Horizons mission to Pluto spectacularly confirmed that the entire solar system boasts water ice, as well as other frozen volatile materials. The composition of these ices sheds light on the properties of their home worlds and gives clues to how the solar system formed some 4.6 billion years ago. Near the sun, Mercury has water ice preserved within craters in permanent shadow. (Similar ice appears on Earth’s moon.)

Venus, the hottest planet, can’t claim water ice, but astronomers were surprised to find several types of snow were possible.

Ice could one day power space exploration. Methane, found throughout the solar system, combines with liquid oxygen to yield a type of rocket fuel. That means spacecraft might someday hop through the solar system, refueling from methane ice deposits along the way.

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Mars’ cold temperatures support water ice, including on its North Pole.

Larger bodies in the asteroid belt, like Ceres and 24 Themis, appear to be full of water ice — in fact, Ceres may have more fresh water than Earth! Ceres’ icy volcano, Ahuna Mons

Europa, Enceladus and other moons of Jupiter and Saturn have ice in abundance.

Plates of ice churn and break apart on Europa (above), while Enceladus (below) boasts an icy, fractured surface.

Saturn’s rings are practically nothing but water ice.

BACKGROUND: LISA ALISA/SHUTTERSTOCK. IMAGES: NASA

Water, Water Everywhere

could then easily combine with oxygen, forming our H2O ice. Planetary scientists tested this by Clearly, water ice is more abundant examining the hydrogen atoms in today’s p than we once thought. But did our water. Deuterium, a type of hydrogen solar system just get lucky? And where with a neutron, is heavier than regular Hydrogen did it come from in the first place? The hydrogen. Scientists can classify water answers lie within water itself. samples, and compare their histories, by The components of water ice learning how many of those hydrogen atoms e— hydrogen and oxygen atoms — are deuterium. They’ve found that the ice p have been around for much of the on comets has deuterium concentrations n universe’s history, but of course it’s very similar to the water in our oceans. not water till they’re combined. The match means our water ice stores have Deuterium Astrophysicists think that happened the same cosmic origin as the solar system’s during the earliest days of our solar comets — among its oldest known objects. system, when the sun and planets were So, we know our watery bounty is not unique, nothing more than a swirling cloud of hydrogen since the same conditions likely occurred during and dust particles. If high-energy particles from the formation of any other solar system. Water deep space, called cosmic rays, happened to hit is likely similarly abundant around other planets, one of those hydrogen atoms, it became ionized, raising the odds of finding life as we know it, or stripped of its electron. Ionized hydrogen atoms at least habitable conditions, somewhere else.

Water’s Envoy

Pluto and other Kuiper Belt objects also boast surface and subsurface collections of ice.

e-

The sun has a much lower deuterium concentration than our oceans, suggesting that much of Earth’s water comes directly from the initial pre-solar cloud. Just think: Part of every sip of water you drink could be older than the sun.

Ice, Ice, Baby? Ice may be responsible for life itself. By analyzing the light from molecular clouds, astronomers have observed not just H2O, but 200 different molecules — including H2, carbon dioxide and ammonia — existing either as gases or in ice that coats dust grains. These molecules can interact to produce complex organic compounds, which could generate DNA, RNA and amino acids. Such biomolecules or their precursors could have ridden to Earth on comets or asteroids to seed life on our planet — and possibly elsewhere. Scientists at the NASA Ames Research Center went even further in 2015 when they exposed the organic molecule pyrimidine, found in meteorites, to interstellar conditions. Frozen in ice under ultraviolet radiation, high vacuum and low temperature, the pyrimidine turned into uracil, cytosine and thymine, major components of earthly DNA and RNA. While we have not yet found complete biomolecules or their forerunners in molecular clouds, these are promising results. We may soon find that life’s true cradle may be the cold and seemingly hostile environment of interstellar ice.

The ice giants, Uranus and Neptune, likely have rocky cores surrounded by water, methane and ammonia ices.

FROM TOP: ALISON MACKEY/DISCOVER; NASA (3)

Rocky core

Icy mantle

A vacuum chamber at NASA’s Ames Research Center exposes ices found on meteors to space-like conditions. The radiation and harsh temperatures broke down pyrimidine in the ice and formed new compounds related to life, such as uracil and cytosine.

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Surviving Space

KNOWING

Settle the final frontier.

WORTH

BY KOREY HAYNES

Hundreds of humans have orbited Earth since space exploration began more than half a century ago. In that time, astronauts have walked on the moon and even endured more than a year in microgravity. But becoming a multiplanetary species — whether to flee a dying world or just explore the unknown — means learning to live without easy access to Earth’s resources and conditions. The first space settlers will face some challenges as old as life itself, while other problems will rear their heads for the first time. Humans must solve them all if we want to survive beyond Earth’s warm embrace.

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THE PROBLEM

Coming Down Is Hard to Do Floating in space may look fun, but it’s also problematic. Humans, plants and other animals all evolved to survive 1 g of force, the average gravity they feel at Earth’s surface. The body does less work in zero gravity, and returning to normal gravity strains muscles, hearts and the whole cardiovascular system. While the moon and Mars, humanity’s next destinations, do have some gravitational pull, the moon packs about one-sixth Earth’s gravity, and Mars boasts roughly one-third. Scientists think it would be tough to adapt to Earth after living for years on the Red Planet. But what if Martian settlers stay there? And what about space explorers who don’t want to touch the ground at all?

THE SOLUTION

Take Yourself for a Spin THE PROBLEM

Astrogrub While our technology has advanced beyond spears and ceramic jugs, food and water remain an eternal challenge. Astronauts on the International Space Station (ISS) and other nearby outposts can survive on supplies shipped from Earth, but for any human settlement to persist farther out, the thin thread of an Earth-based supply chain will prove dangerously fragile. If there’s a crop failure on Mars — it occasionally happens in Antarctica’s greenhouses, which serve as analogs — colonists can’t live on astronaut ice cream for the two years it would take for emergency supplies to arrive.

THE SOLUTION

NASA/KSC (2)

Mining and Greenhouses The only sustainable answer is to mine and farm the solar system. Water mining on comets and asteroids should be far more cost-effective than heaving tons of H2O out of Earth’s gravitational grip. Greenhouses are also cheaper than shipping. Scientists have already grown small test plots aboard the ISS. Russia’s orbiting Mir station flourished with plants, from wheat to weeds. And perhaps most intriguing, research suggests that Martian and lunar soil could be used to grow crops like wheat and even potatoes. But just in case those crops fail, Red Planet settlers would want enough in storage to make a doomsday prepper seem ill equipped. Space colonizers could even adopt a DIY approach to building materials by baking lunar and Martian regolith — rocks and dirt — into ceramics, rather than transporting heavy supplies like steel and metal.

Long-term orbiting astronauts could live in a Stanford Torus. The structure, developed by NASA and Stanford University in the 1970s, is a design for a space station: essentially a hollow ring that spins four times per minute. (Picture 2001: A Space Odyssey.) This motion provides “artificial gravity” by means of centrifugal force, like a sock stuck to the drum of a spinning clothes dryer. Astronauts and cosmonauts have spent over a year in zero gravity with few problems, and those mostly arise when reacclimating to Earth. So it’s logical to assume low gravity would be safe, perhaps even pleasant, for short missions. But we have no long-term studies of how humanity would cope with years spent in the gravity of another world. Our best evidence is that between 1969 and 1972, a dozen men walked on the moon’s surface for a few days with no ill effect. Before we discover if we can survive as a species beyond Earth, we should probably take a few more walks out there.

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Surviving Space

THE PROBLEM

Off-Planet Birds and Bees Even if well-prepared adventurers can overcome all these challenges, there’s still a civilization-stopping hurdle that science has barely explored: Can we procreate in space? The problems of radiation and low gravity are likely magnified for developing babies and growing children. And exposing babies to radiation and 0 g is ethically fraught, so it’s also hard to learn more. But before an infant even arrives on the scene, scientists still don’t know how important gravity is for successful sex — in a Darwinian sense, anyway. Experiments in zero gravity with rats, quail eggs, jellyfish and wasps have not been promising for fertilization, implantation or gestation, with different problems arising within each species and at each stage. That’s not to say the results are especially damning, though. Many were simply inconclusive.

THE SOLUTION

Let’s Change the Subject The truth is that more than a half-century after first venturing into space, we’re still in the dark when it comes to space sex. As far as we know, it’s never even happened between humans, though rumors abound. Whether it’s because space agencies are more focused on short-term goals or because they’re simply prudish, little research has gone into whether humans have any hope of continuing the species off-world. Maybe one day!

THE PROBLEM

Cosmic Storms Earth’s atmosphere and magnetic field protect us from the constant stream of harmful solar radiation and other occasional deadly particles from deep space. Venturing beyond Earth’s protection is a gamble. But how dangerous is it? Nuclear accidents and attacks show that short, severe exposure to radiation is deadly for humans. During solar

storms, space-farers hunker in shielded areas of their stations akin to tornado or bomb shelters. But scientists still don’t know how the human body will react to sustained low-level doses of radiation inherent in space travel. There are few ethical ways to find out, however: An accidental decades-long exposure in Taiwan suggests it’s not as simple as “more radiation is bad.” When 1,700 apartment buildings were unintentionally exposed to radiation from 1983 until 2005, residents actually had lower rates of cancer and birth defects.

Gimme Shelter Scientists still don’t have a solution for shielding interplanetary astronauts from radiation. But a space station in equatorial low-Earth orbit (ELEO) would sit inside Earth’s magnetic field. It would receive most of the benefits of radiation shielding that ground-dwellers enjoy. Al Globus, a researcher with San Jose State University and NASA Ames Research Center, has put a lot of thought into such a dwelling. “ELEO is the best place for [safe] radiation by a large margin,” he says. For people who want to travel beyond Earth’s magnetic field, the only other safe and long-term option might be

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underground. Hiding some 15 feet under the surface of Mars or the moon would provide all the radiation shielding of home. Both those worlds also have natural caves. Ancient underground lava flows have carved tube-like caves that can stretch up to 1,000 yards wide and extend for many miles. Occasionally, parts of the cave ceiling can collapse, creating a large skylight opening. By securing these natural skylights with thick glass, the vast interior spaces could be pumped full of air and used as a pre-fab home. “You can imagine setting up a large mirror farm on the surface to bounce light into the tunnel,” says Jeff Greason, CEO of Agile Aero and an aerospace expert. Such a setup would bring sunlight to living or green spaces. Humanity’s future could look much like our past in Earth’s caves.

NASA/KSC

THE SOLUTION

Such Great Heights 238,900 miles Humans walking on the moon represent our farthest reach “above” Earth’s surface.

LEFT: NASA/KSC. RIGHT FROM TOP: NASA (2); TED SOQUI/GETTY IMAGES; JIM RICHARDSON/NATIONAL GEOGRAPHIC CREATIVE; COURTESY AHMED GABR; SCIENCE AND SOCIETY PICTURE LIBRARY/GETTY IMAGES

220-250 miles Humans live comfortably on space stations and can explore outside. BYO air, and we seem to do just fine for periods brief and not so brief. Valeri Polyakov spent more than 14 straight months on Russia’s space station, Mir. 39,000 feet (7 miles) The human altitude record is roughly tied among stowaways who climbed into passenger plane wheel wells. Doctors think hypothermia lowers oxygen needs, letting them survive, though more than half of the attempts result in death. 13,200 feet Groups living in mountain ranges at high elevations have evolved to survive the thin air there. In the Andes, locals show higher levels of hemoglobin in their red blood cells, boosting their oxygen-carrying capacity. 0 feet Near sea level, humans enjoy the world that we’ve evolved into. 1,091 feet below sea level In a record-setting deep-dive in 2014, Ahmed Gabr, wearing only scuba gear, descends into the Red Sea for 15 minutes. It took him nearly 14 hours to resurface, as he carefully avoided decompression sickness. 35,797 feet (almost 7 miles) below sea level Jacques Piccard and Don Walsh dive into the Marianas Trench’s Challenger Deep — Earth’s deepest point — inside Trieste, a specially reinforced vehicle, in 1960. The pressure there is a crushing 1,000 times that at sea level.

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Yeast

KNOWING

A fungus of many trades.

WORTH

BY CARL ENGELKING

Our relationship with yeast is like a college friendship that grew beyond keggers and into distinguished adulthood. We’ve partied with our eukaryotic wingmen dating back Yeast cells to at least 7000 B.C., using them in foods and head-spinning libations. In 1680, Anton van Leeuwenhoek, godfather of microscopy, gazed upon yeast for the first time; that’s when we started moving past the party years. We still throw down with yeast, but we’ve grown up and have jobs now. These days, the fungus is a laboratory champion, an engine of industry. It underpins Nobel Prizewinning breakthroughs and churns out biofuels and novel medicines. Indeed, yeast may someday save our lives.

There are over 1,500 species of yeast. The microscopic, single-celled, eukaryotic fungus is found everywhere, and we know it well. Beer barons control its evolution, and scientists fiddle with its DNA. One-third of yeast genes have counterparts in the human genome, many of which are associated with diseases, such as cancer. And given that yeast is inexpensive, reproduces quickly and is easy to work with, it’s the most well-studied organism known to humans.

Winning Nobel Prizes Yeast is basically the MVP of lab organisms. It’s helped scientists claim five Nobel Prizes in the 21st century (2001, 2006, 2009, 2013 and 2016). Yoshinori Ohsumi, the most recent prizewinner, used baker’s yeast to identify genes crucial in autophagy, the process by which cells recycle their components. Diseases like Parkinson’s, Type 2 diabetes and cancer have been linked to disruptions in this cellular recycling process. The autophagy machinery in yeast cells is similar to that in human cells, and Ohsumi’s work, which began in the 1990s, gives scientists new targets for possible treatments.

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BioSentinel Mission 2018 Planned for launch in July 2018, NASA’s BioSentinel spacecraft (below) will expose yeast to the ravages of interplanetary radiation. Cards dotted with a series of microwells housing three strains of yeast will be activated (via a hydrating injection) at different points along an 18-month timeline. Scientists will track the yeasts’ growth and metabolic activity. The experiment will be replicated aboard the International Space Station and on Earth for comparative samples. It’ll be the first experiment elucidating the biological effects of radiation beyond low Earth orbit in over 40 years, according to NASA.

BACKGROUND: SIRO/SHUTTERSTOCK. LARGE BUBBLES: PHYSICX/ SHUTTERSTOCK. TOP: THOMAS DEERINCK/NCMIR/SCIENCE SOURCE. BOTTOM: NASA (2)

What Is Yeast?

Gross Yeast Tricks

Pasteur’s Revenge Soaked in the vinegar of defeat after the Franco-Prussian War, French chemist and microbiologist Louis Pasteur vowed to avenge his homeland by hitting the Germans where it hurt: the beer. A pioneer of immunization and food sterilization, Pasteur (below) also experimentally proved in the 1850s that yeasts drove the fermentation process, gobbling sugars to produce ethanol, carbon dioxide and a host of other compounds essential to beer. He identified microbes that could spoil a batch of beer and devised methods to keep them out, preventing contamination and enhancing beer’s flavor. By the time the war broke out in 1870, Pasteur, jaded by personal losses, forbade publishing his brewing secrets in German, hoping to give French brewers enough scientific artillery to threaten Germany’s chokehold on the industry. Pasteur wanted France to produce the world’s finest beer, or what Pasteur dubbed “the beer of revenge.” His work inspired a generation of beer barons, including J.C. Jacobsen, who founded Carlsberg in Denmark. In the 1880s, scientist Emil Hansen isolated a yeast strain and named it Saccharomyces pastorianus in homage to Pasteur — a man who, reportedly, didn’t even like the taste of beer.

CENTER: WELLCOME LIBRARY, LONDON. BOTTOM: BOLT THREADS

Today, yeasts are programmed to secrete human proteins used in vaccines, insulin and other biopharmaceuticals.

In 2015, British blogger Zoe Stavri reportedly baked a sourdough leavened with yeast from a vaginal infection — granted, it was a very small amount. Candida albicans, the typical culprit behind such infections, likely played a role in this baking project. Doctors do not advise repeating this at home.

Biofuels We’ve used yeast to convert plant cellulose and starch into biofuels like ethanol for decades; however, the process still isn’t efficient, and scientists are genetically altering yeast to change that. Yeast doesn’t function well in high alcohol concentrations, so upping its resistance is one objective. Also, coaxing yeast to move beyond glucose to sugars found in non-food plant fibers could lower costs.

DNA Slipping We’ve been slipping foreign DNA into yeast since 1978, when Gerald R. Fink at MIT figured out how. In 2015, scientists swapped genes crucial for yeast survival with human versions, and of the 414 genes they tested, nearly 50 percent of the human proteins could keep the yeast alive.

Beard Beer, from Oregon-based Rogue Ales, is brewed with a strain of wild yeast harvested from nine beard hairs plucked from brewmaster John Maier. The Baltimore Sun said the American wild ale has a “smooth finish and citrus notes.”

As it stands, 90 percent of car engines still run on petrol, as opposed to alcohol.

Spider Silk In the lab at Bolt Threads in Emeryville, Calif., technicians are using yeast enhanced with spider DNA to brew silk proteins that are spun into textiles. Bolt researchers control fabric qualities, like stretch and softness, by manipulating protein chemistries, fermentation conditions and other aspects of the spinning process. In 2016, the company received $50 million to scale up production, even partnering with apparel company Patagonia to develop designer products.

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EVERYTHING

The Dark Universe

KNOWING

See the light on dark matter and dark energy. BY ADAM HADHAZY

Say the universe is a restaurant entrée. Astonishingly, everything that we can discern on the plate, so to speak — protons, paramecia, people, planets, pulsars, you name it — altogether adds up to a mere sprig of parsley. To a cosmic garnish such as ourselves, the vast majority of the universe is invisible, an empty plate dominated by “dark” matter and a “dark” energy. The effects of these phenomena are writ large in space, yet their true natures have frustratingly evaded every instrument we’ve brought to bear.

How Do We Know It’s There? iThe cosmos would fling itself apart were it not for a gravitational glue provided by tremendous, yet unseen, amounts of mass. Factoring in all the ordinary matter we cannot see — contained in exoplanets, galactic gas clouds, and black holes, none of which emit light — still isn’t enough to make up the difference.

Gravitational lensing Cosmic structure

iThe immense gravity from clusters of galaxies warps the light coming from more distant objects, acting like a cosmic magnifying glass. This gravitational lensing is far too strong to be caused by plain ol’ matter. iGas filaments (in orange at right) connect scattered groups of galaxies. This vast cosmic web makes structural sense only when explained by underlying concentrations of dark matter (blue). iOrdinary matter also can’t explain temperature fluctuations in the Big Bang’s relic afterglow. Known as the cosmic microwave background (CMB), it’s visible everywhere in the sky as microwaves.

CMB

What Could It Be?

How Do We Look for It?

Probably an elusive kind of subatomic particle (or particles) that outnumbers normal matter particles by 5 to 1. The two leading contenders:

Typically, dark matter aloofly passes through Earth, but in rare instances it might interact with normal matter; the trick is to tell when. Experiments like SuperCDMS and LUX-ZEPLIN rely on metal germanium crystals and liquid xenon, respectively, as their LUX detector dark matter finders. Come 2020, tank these experiments will run in deep underground mines, shielded from the cosmic radiation striking our planet’s surface. The Axion Dark Matter eXperiment, started at Lawrence Livermore National Laboratory before moving to the University of Washington, seeks the subtle signatures — just a trillionth of a trillionth of a watt — left by axions as they’re snagged by a strong magnetic field. Telescopes are also on the lookout for telltale gamma rays from space, in case dark matter commits the particle version of suicide and self-destructs.

WIMPs – Cute acronym for weakly interacting massive particles, much heavier than the familiar protons and neutrons in atomic nuclei. WIMPs would “feel” matter through gravity and the so-called weak force, which is responsible for why atoms radioactively decay. Axions – A two-for-one special? Physicists originally cooked up the axion to explain why neutrons don’t spin in electric fields. The particle’s attendant properties — insanely low-mass, mostly indifferent to matter and highly abundant — neatly check off many dark matter boxes, too.

FROM TOP: NASA/ESA/S. BECKWITH (STSCI)/THE HUBBLE HERITAGE TEAM (STSCI/AURA); NASA/ESA/JUDY SCHMIDT; ESO/ILLUSTRIS COLLABORATION; ESA/THE PLANCK COLLABORATION; C.H. FAHAM

WORTH

FROM TOP: ROEN KELLY/DISCOVER; NASA/GODDARD SPACE FLIGHT CENTER/CONCEPTUAL IMAGE LAB; NASA

How Do We Know It’s There? Space telescopes studying the Big Bang’s relic radiation (the cosmic microwave background) have found the universe is almost perfectly flat. That means light travels in straight lines unless it encounters mass. Scientists say this only really makes sense in a universe brimming with some kind of dark energy. Dark energy would also explain why our universe’s expansion is accelerating. Although we’ve known for about a century that galaxies are receding from ours, scientists long speculated that matter’s gravitational heft would eventually slow cosmic expansion — maybe even reverse it, culminating in what’s called a Big Crunch. In 1998, however, astonished astronomers discovered the opposite. A certain kind of exploding star, called a supernova, turned out to be fainter than expected in the distant past, indicating that the universe is ballooning at an ever-faster rate, and has been for nearly half of its 13.8 billion-year existence. At the current clip of cosmic growth, the distance between galaxies will double in 10 billion years.

What Could It Be? Many astrophysicists wager that dark energy is inherent to the empty vacuum of space, comprising the universe’s bulk by virtue of being near-ubiquitous. After all, there’s a lot of emptiness out there.

Present day

Stars, galaxies develop First stars

How Do We Look for It?

Cosmic background afterglow

Huge sky surveys measuring the distribution of billions of galaxies over cosmic history could offer clues about the evolution of dark energy, as well as its enigmatic properties. Key missions include NASA’s Wide Field Infrared Survey Telescope (WFIRST) and the European Space Agency’s Euclid space telescope, plus the ground-based Large Synoptic Survey Telescope, opening in Chile in the 2020s.

27% Dark matter

Composition of the Universe

Expansion continues

5% Regular matter

68% Dark energy

Inflation Big Bang

WFIRST

DISCLAIMER

Could Dark Matter and Dark Energy Be Wrong? Oh yeah, big time. It could be that neither dark matter nor dark energy exists. Sure, it would require a major rejiggering of Albert Einstein’s extremely well-tested theories: Gravity would somehow have to operate differently on epic, cosmic scales. But don’t count out the possibility that current ideas about the universe are totally wrong. Many scientists freely admit they’re really — ahem — in the dark about the dark universe.

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EVERYTHING

The Perfect Battery

KNOWING

Powering up our lives.

WORTH

BY STEPHEN ORNES

Batteries symbolize our love affair with convenience. They liberate us from wires by juicing up our smartphones, laptops and cars. With gadgets fully charged, we can go anywhere, do anything. One hundred percent power feels secure. But when the charge runs dry, we’re screwed. The good news? Engineers are trying to create the perfect battery. It is efficient and safe, and it packs a lot of oomph using little space. It’s made from abundant, cheap and nontoxic materials. It maintains a charge over thousands of recharges. It can store energy generated by wind turbines and solar cells. But significant hurdles remain in this quest, and the outcome will determine our electronic future. Without better batteries, tomorrow’s doodads or dreams of using alternative energy will remain points of endless frustration. Or maybe frustration is inherent. In 1883, Thomas Edison warned that chasing the perfect battery is a fool’s journey: “a catchpenny, a sensation, a mechanism for swindling the public by stock companies,” he wrote. Working on the latest, greatest battery brings out a man’s “latent capacity for lying.” Sensation or game changer? Here’s your guide to the perfect battery.

Inside a battery, chemical reactions involving a material called an electrolyte cause electrons to accumulate in the negative terminal, or anode, and flow when it’s connected to the positive terminal, or cathode. Recharging a battery reverses that process — returning electrons to the anode, where they can be reused.

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CHARGING DISCHARGING

Electron flow is reversed when recharging

Electrons

Flow of electrons around circuit Anode Negative terminal

Electrolyte Cathode solution Positive terminal

CLOCKWISE FROM TOP LEFT: VECTOREPS/SHUTTERSTOCK; ALISON MACKEY/DISCOVER; RUMRUAY/SHUTTERSTOCK; KACZOR58/SHUTTERSTOCK

How a Battery Works

Two Measures of Success

1

Big energy, little package: Batteries are often compared by their specific energies, measured in watt-hours per material mass. The higher the measure, the more pep packed into the unit.

CURRENT ENERGY RELATIVE TO MASS

Battery Development: Highs and Lows

PREDICTED FUTURE PEP (Wh/kg) Magnesium-ion: 400 Lithium-air: 1,000

SUCCESSES 1800: Voltaic pile. Italian physicist Alessandro Volta builds the first electric battery by layering plates of different metals (anodes, cathodes) separated by brine-soaked cloth (electrolyte). The battery creates a weak but steady current.

Lead-acid (to start cars) Nickel-cadmium (rechargeables for flashlights, toys) Alkaline (flashlights, toys) Lithium-ion (laptops, handheld mobile devices) 0

2

50

100

150

200

WATT-HOURS/KILOGRAM

Cycles. How many times can you recharge a battery to its highest possible capacity? This is also a measure of how long your battery will last. Lithium-ion batteries are great cyclists, able to recharge hundreds of times. Adding nanoparticles to batteries can speed up recharge time, some studies have shown.

1957: Alkaline battery patented. Alkaline batteries use alkaline electrolytes instead of acid, and they remain the workhorses of the battery world. These are most of the AAs, AAAs, Cs, and Ds bought everywhere. Lithiumion: 500-1,000 recharges

The Quest to Make Lithium-Ion Batteries Better and Safer FROM TOP: ALISON MACKEY/DISCOVER; ALEXLMX/SHUTTERSTOCK; WK1003MIKE/SHUTTERSTOCK

1859: First rechargeable battery. French physicist Gaston Planté’s lead-and-sulfuric-acid battery can be recharged with a reverse current. This type is still found in today’s cars. The technology hasn’t changed, but the recipe has been improved.

Among today’s batteries, the family of lithium-ion batteries reigns. They’re used in mobile phones, cameras, laptops and electric cars. They’re more efficient and last longer than their predecessors. And because lithium is the world’s lightest metal — it can even float — it’s used to make lightweight batteries. The price is right, too: After a quarter-century on the market, lithium-ion batteries are cheaper, thanks to better manufacturing techniques. Just one problem — the liquid electrolyte in most lithium-ion batteries can burst into flames. Gerbrand Ceder, a materials scientist at the University of California, Berkeley, has developed a solid electrolyte that contains nothing combustible and that could last longer. “A solid-state battery would be the ultimate battery in terms of safety, and probably in terms of lifetimes as well,” he says.

1979-80: First commercially viable lithium battery. Engineers demonstrate rechargeable, efficient batteries that use lithium ions and have cathodes with cobalt. Today, they’re the battery of choice in electronic devices.

FAILURES 1915: A watery grave. After the U.S. submarine F-4 sank in the Pacific, an investigation blames corrosion in the battery tank. All 21 people aboard sank with the sub. 2010: Fire in the air. The fatal crash of a UPS jet is blamed in part on a fire that began in a storage area for flammable lithium-ion batteries. 2012: Perfection that wasn’t. Startup battery developer Envia, powered by $11 million from investors and a government grant, claims that its new electric-car battery has an energy density over twice that of existing electric-car batteries. Executives boasted about a 200-mile range. Reality bit when Envia and other battery technology companies failed to reproduce the stellar results.

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KNOWING

The Perfect Battery

Material Help

Future Innovation

Lithium and cobalt, two ingredients of lithium-ion batteries, are relatively rare. About half of the world’s cobalt supply comes from the war-torn Democratic Republic of the Congo. Can we make a perfect battery from more abundant, less controversial materials? Sodium-ion batteries combine low cost with high efficiency, and sodium is more abundant than both lithium and cobalt. Plus, their energy density is close to that of lithium, and they’re particularly appealing for storing energy from wind and solar farms.

How far outside the box can a battery go? Some engineers are working on projects that would redefine the battery as we know it.

A worker in the Democratic Republic of the Congo descends into a crude mine where cobalt, an ingredient of lithium-ion batteries, is extracted.

Magnesium-ion batteries could pack more energy than lithium-ion batteries and might be safer, but they’re harder to charge. Ceder, the Berkeley scientist, says this technology is still in its infancy and is hard to predict. He likens today’s progress on magnesium to the early research in the 1980s on lithium-ions. Hydrogen fuel cells also pack a lot of energy in a small package. The fuel cells combine hydrogen, water and oxygen to generate electricity. Automakers have begun rolling out cars powered by them, and a few states have installed hydrogen refueling stations. But hydrogen remains controversial. Critics point out that it’s expensive to produce the fuel cells and they don’t store a lot of power. Hydrogen fueling sites, like this one in West Sacramento, Calif., are popping up in the United States.

Quantum action. In the past few years, physicists have investigated ways to produce energy from qubits, or quantum-mechanical systems like subatomic particles. Their reasoning goes something like this: As particles drop into their lowest energy state, they release energy. If we can collect that energy, we can use it in batteries, and recharge by returning them to a higher state. There’s an additional predicted quantum quirk that doesn’t happen with ordinary batteries: The more qubits you have, the faster they recharge. Biobatteries. What about batteries powered by living organisms? Some bacteria produce electric currents when they eat or convert sugars into usable energy. Last December, physicists at the State University of New York-Binghamton unveiled a disposable paper battery that generates a trickle of power from trapped bacteria. Self-destructing battery. Scientists at Iowa State University have developed a lithium-ion battery that dissolves in water in 30 minutes. One application could be powering temporary medical devices in the body. Other versions of this technology cause battery destruction when exposed to heat or light.

Researchers have created a battery that dissolves in water.

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CLOCKWISE FROM TOP: MICHAEL ROBINSON CHAVEZ/THE WASHINGTON POST/GETTY IMAGES; ASHLEY CHRISTOPHERSON AND REZA MONTAZAMI/IOWA STATE; CALIFORNIA ENERGY COMMISSION

EVERYTHING

WORTH

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OUT THERE

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A Look at the Universe and All Its Wonders

WEBB DESIGN Technicians at Goddard Space Flight Center in Greenbelt, Md., position the massive James Webb Space Telescope for tests in its assembly room earlier this year, in preparation for a 2018 launch. While Webb will be the most powerful space telescope ever built, astronomers are already designing its successor. The High Definition Space Telescope will have a mirror nearly twice the diameter of Webb’s 21.3-foot gold mirror and should be powerful enough to detect evidence of life on alien planets. Read more on page 84.  ERNIE MASTROIANNI; PHOTO BY NASA/DESIREE STOVER

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Meet the Next-Generation Space Telescope Using the High Definition Space Telescope, astronomers hope to discover life in the universe. BY KOREY HAYNES

In 2018, when the James Webb Space Telescope (JWST) opens its enormous eye on the universe and begins collecting data, the astronomers who envisioned it and the engineers who designed and built it will celebrate and cheer. But even as the first waves of data beam down to Earth, another team of scientists will be hard at work designing its replacement. In fact, they have already begun. Conceiving of, researching, and building science’s biggest, most valuable tools of inquiry — the Large Hadron Collider, or the Hubble and James Webb space telescopes — requires dozens of years, hundreds of expert panels and team meetings, and billions of dollars, and the gears that march these projects through the bureaucratic assembly line turn slowly. So it should come as no surprise that, while it won’t fly until at least the mid2030s, astronomers are already planning the next next large space observatory, currently known as the High Definition Space Telescope (HDST). Since the moment Hubble left the launchpad, different groups have discussed what this future project might look like, but they all agree on the basic requirements and objectives. “There’s not a million ways to do it,” says Sara Seager, astronomer at the Massachusetts Institute of Technology. She was also a co-chair for the committee tasked by the Association of Universities for Research in Astronomy (AURA) to define a vision for HDST. “You have your science drivers and your engineering constraints, and you try to find a happy

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medium among all of those.” So, balanced between technologies within reach and the most pressing astrophysics questions of the day, the basics are already apparent to Seager and her fellow visionaries. While JWST will focus specifically on the infrared portion of the spectrum, HDST will be a true Hubble successor, with capabilities in the infrared, optical, and ultraviolet. JWST’s 6.5-meter mirror already dwarfs Hubble’s comparatively modest 2.4 meters, but HDST will span about 12 meters, matching the largest telescopes currently on Earth. And while earthbound telescopes will have advanced to 30 meters by HDST’s era, the space telescope will, like JWST before it, fly not just in space, but at the distant L2 Lagrange point, well beyond the moon’s orbit. It will command an uninterrupted and unclouded view of the heavens, far from Earth’s atmosphere or its photobombing bulk. From this pristine vantage point, it will peer into the farthest reaches of the cosmos and hunt the holy grail of astronomy: another living Earth.

THE SEARCH FOR LIFE In 1995, exoplanets catapulted from science fiction to cutting-edge science when Michel Mayor and Didier Queloz discovered the first one orbiting a solartype star. Over the next decade, searches from both the ground and space revealed a handful more, then dozens. In 2009, the Kepler spacecraft opened the floodgates, and hundreds and then thousands of exoplanets poured onto the scene.

DON DIXON

→

Astronomers have big dreams for the upcoming telescope and its potential starshade, which would enable it to block a star’s glare and hunt for habitable worlds.

July/August 2017 2016 DISCOVER

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OUT THERE

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Measuring Up

JWST 6.5 meters

Hubble 2.4 meters

HDST 11.7 meters

The High Definition Space Telescope will be nearly twice the diameter of the upcoming James Webb Space Telescope. It already dwarfs Hubble, which remains for now the premier in optical observing.

The James Webb Space Telescope team stands in front of a full-size model at NASA’s Goddard Space Flight Center, where it is being assembled. The Webb is roughly the size of a tennis court when its sunshield is fully extended, and the High Definition Space Telescope will be almost twice as large.

Hubble Deep Field,” observes Marc Postman from the Space Telescope Science Institute, another member of the AURA team. And while E.T. might be worth 100-plus hours of telescope time, astronomers face reasonable odds that after such an investment, the planet might turn out to be a barren and arid exo-Mars instead of an exo-Earth. It is not a feasible way to conduct a large-scale study. Astronomers need a different tool — and so HDST was born. Instead of using transits, Earth-twin investigators will look for the planets directly, a feat that carries its own stiff engineering requirements. They’re within reach, but they represent the most pressing challenges for HDST.

TOP: AURA. BOTTOM: NASA/GSFC

But astronomers know only the slimmest of details for most of these planets. They know a planet’s mass or its size — they know both only in serendipitous cases — and the distance between it and the star it orbits. Determining a planet’s composition from this information is an exercise in intelligent guesswork, modeling, and puzzle solving. Even now, scientists have directly observed a handful of specific molecules that comprise a planet’s atmosphere in only a few dozen systems, and those are the brightest, hottest giant planets that hold no hope of life. Far from being clinically detached, many astronomers dream of finding another Earth. They want to find life. It should be no surprise that some of the leading exoplanet researchers — among them Seager and Bill Borucki, who designed and headed Kepler — describe their motivations along these lines. “I think all of humankind is interested in our place in the galaxy, in life, in the universe,” Borucki says. “And the answer to that lies along finding intelligence, finding life, and finding planets on which this life could exist.” These are very distinct tasks. Astronomers know of a handful of planets already where life could be present. These planets are the right size to have rocky surfaces, and they orbit in the habitable zone of their star where liquid water could potentially exist. Yet astronomers cannot ascertain whether water is actually present. And even if water is present — is life? Answering this question means moving beyond a planet’s size and peering deep into its gas shroud to find the telltale signs of a living atmosphere: water, oxygen, carbon dioxide, methane, ozone. Only the interplay of such substances can reliably inform astronomers about the actual presence of life, instead of its mere potential. Transit studies are the current best method for learning the components of an exoplanet’s atmosphere. Astronomers watch a host star as its planet crosses in front and measure how the observed starlight changes as the planet’s atmosphere blocks and filters it. This method yields rich information when the planet is large, puffy, and hot, like a Jupiter or Neptune on a tight orbit. But for a planet with Earth’s comparatively small size, compressed atmosphere, and more distant orbit, the change in light is simply too small to measure, even for future giant telescopes. JWST will perform spectacular transit observations with so-called super-Earths, planets one and a half to twice Earth’s radius. But these planets are not especially Earth-like. So unless astronomers are lucky enough to find an extremely nearby Earth-sized planet with a cool M-dwarf host star, neither JWST nor any of the accompanying and upcoming fleet of exoplanet missions will have the ability to characterize a true Earth twin in the habitable zone. “Even around an M-dwarf star, the time required to perform a full spectroscopic measurement of a transiting Earth-sized exoplanet with JWST would be similar to that used for the

Hubble

JWST

Jupiter

Earth Venus

HDST

Modelers compare the resolution of a distant galaxy achieved by the High Definition Space Telescope (HDST), James Webb Space Telescope (JWST), and Hubble. Only HDST is able to clearly pick out bright star-forming regions from older red stellar populations. Astronomers model how the solar system would appear to an observatory the expected size of the High Definition Space Telescope with an internal coronagraph to block out a central star’s light. An Earth twin and its blue color could be detected with 40 hours of observing time.

LEFT: L. PUEYO, M. N’DIAYE. RIGHT: D. CEVERINO, C. MOODY, AND G. SNYDER

Strong science requires repeatability; Earth-twin hunters need a whole sample of potential Earths to study. Seager poses the question: “How many Earth-like exoplanet atmospheres do you think you need to get a handle on what’s really going on, including the search for life? Do you think it’s one? 10? 100? 1,000?” She settles on “dozens.” It isn’t an abstract thought experiment. HDST will be exactly as powerful as is needed to answer the questions astronomers pose. Exceeding these specifications wastes precious budget dollars and can lead to impossible engineering demands. Underperformance would leave astronomers’ questions unanswered. And Seager has not just a question, but a mission: find the next Earth.

STELLAR ARCHAEOLOGY But HDST will be a telescope for the whole astrophysics community. Postman studies the formation and evolution of galaxies and large-scale structure in the universe, and he looks forward to HDST’s capabilities on these much grander scales. “Where do galaxies get the gas to make their stars?” he asks. “We only understand that at a rudimentary level.” To make stars, galaxies must capture gas from the intergalactic medium. And energetic activities like bursts of star formation that form young and violent stars, as well as black hole evolution, can in turn spew gas back out of galaxies. Astronomers have many models of this cycle, but Postman says none of them has been verified at the detailed level they desire. Currently, Hubble tracks the position and motion of gas around galaxies by studying how their gas absorbs light from faraway quasars — bright pinpricks of light caused by active, much more distant galaxies far in the background. But Hubble usually can observe only one quasar per intervening galaxy, and that only in a small number of targets. “But if

you had a telescope in the 10-meter class,” Postman says, “there would be 10 to 20 quasars behind every galaxy out to 10 megaparsecs [32.6 million light-years] that would be bright enough to pursue for these studies.” This would allow astronomers to draw spatially resolved maps of the gas around these galaxies. “That’s a game changer,” Postman declares. Astronomers also are interested in so-called stellar archaeology, the history of star formation in galaxies. How many stars of every size did galaxies form, and how long ago? Again, Hubble attempts these measurements now, but has the angular resolution to study only the Milky Way and our closest neighbors in the Local Group of galaxies. HDST could map star formation out to the same 10-Mpc-range. And if researchers can understand the flow of gas that feeds star formation, these maps would be even more informative, painting a fuller picture of the history of the local universe and beyond. The upcoming generation of 30-meter-class ground-based telescopes will join in this search, but their best angular resolution comes in the near infrared, where the color differences between old and young stellar populations are far less dramatic than in the ultraviolet range HDST will access. This difference highlights the complementary nature of the upcoming generation of telescopes. HDST will achieve its highest resolution in the ultraviolet, with the 30-meter telescopes matching it in the infrared. With its enormous team of networked dishes, the ALMA radio observatory can supply the same level of detail in its target range. Together, they will offer the most comprehensive maps of the nearby universe ever seen, delivering unprecedented resolution at the same spatial scale from radio to ultraviolet wavelengths. “It will be revolutionary,” Postman predicts.

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OUT THERE Blocking Out the Stars

Planet

HDST Telescope aperture diameter: 12 meters Inner working angle Separation: 160,000–200,000 kilometers

Starshade diameter: 80–100 meters A starshade is a separate unit from the telescope that flies in formation far from its partner observatory. It blocks out light directly surrounding the star, creating a totally dark “inner working angle,” but allows the telescope to see much closer in than without the shade, when starlight glares too brightly to see planets orbiting nearby.

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Visible

Hubble

HDST

Hubble’s current view of outer solar system worlds, such as Jupiter’s moon Europa, provides the impetus for sending probes flying to the gas giants. But the High Definition Space Telescope could yield rich detail from its orbit near Earth.

TOP: DON DIXON AND ROEN KELLY/DISCOVER. BOTTOM: AURA

dozens of exo-Earths. But there’s another way. For years, astronomers have dreamed of a starshade, an external version of the coronagraph with a delicate and complicated petal structure designed to perfectly eliminate the multispiked “diffraction” pattern of light cast by a faraway star. For a telescope the size of HDST, a starshade would be over 300 feet (100m) across and require that each petal’s construction be accurate to a millimeter. HDST and its starshade would fly nearly 125,000 miles (200,000 kilometers) apart and maintain their flight formation at a precision of a few feet (1m). Such formation flying is difficult, and slewing from one target to another would take days or even weeks as astronomers wait for the starshade to fly the thousands of miles necessary to assume a new position. It also is an unproven technology: No starshade mission has yet flown. But such a design could see smaller, closer-in planets to greater sensitivity than an internal coronagraph and ease engineering requirements on the telescope itself. A starshade mission might fly with another Hubble-sized space telescope called WFIRST-AFTA, set to launch a decade before HDST. If so, it could be a field test for this new technology.

Ultraviolet

THE BUILD Fortunately, astronomers are in agreement about what it will take for HDST to meet these various science goals, which informed their decision to build a 10-meter-class mirror (the exact size has yet to be determined) and fly it at L2. While engineers are already breaking ground to build telescopes three times that size on Earth, a very simple problem caps the size of any space telescope: There must be a way to get it into space to begin with. The largest vehicle planned for the foreseeable future is NASA’s Space Launch System (SLS) Block 2, and even this leviathan rocket — nearly 400 feet (120m) tall and with a payload capacity of 150 tons — is only 8 meters across on the inside. This means that HDST, like JWST before it, must accommodate a foldable, segmented mirror design, with as many as 54 hexagonal pieces. It will blast off Earth folded onto itself in the belly of the largest rocket ever built, and unfold only when it reaches deep space. Getting it to space is only one of the engineering demands. To find those elusive habitable exoplanets, scientists must reach beyond transits to direct imaging. But Earth, for example, is 10 billion times fainter than the sun, and from a distance of tens of trillions of miles away or farther, it would be lost in our sun’s glare. Astronomers need to kill the starlight. Observers know of two ways to block out a central star’s light. The first uses a device known as a coronagraph, which sits inside the telescope and carefully obscures light from the star while letting through light immediately around it. This delicate operation requires an exceedingly well-engineered and very stable telescope where the path of light traveling through the spacecraft is perfectly understood and meticulously mapped, with components correcting the mirror’s shape to keep images stabilized against even the tiniest aberrations. It substantially complicates the overall telescope design, but the depth and clarity of the resulting images would yield thousands of planets and

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OUT THERE

LH 95 in the Large Magellanic Cloud

Orion in the Milky Way

Counting individual stars outside the Milky Way is difficult but extremely valuable to astronomers seeking to understand how stellar populations are born and evolve across the universe. Currently, even stars in the nearby Large Magellanic Cloud blur together in Hubble’s eyes, while the High Definition Space Telescope will count each separate sun.

For now, the AURA team is setting its sights on an internal coronagraph as the higher priority. But, Seager says, “there’s no reason you can’t have both.” The final decision will rest heavily on research conducted even now, as engineers explore how and if promising technology can be delivered in time to fly by the mid-2030s. The telescope itself, and its instruments, will not come easily. HDST will build as much as possible on current technologies either already proven on missions like JWST and Gaia, which is currently mapping a billion stars. It will call on other technologies tested and developed for missions that never flew, like the Terrestrial Planet Finder and the Space Interferometry Mission. Engineers will catch some good breaks as well. Unlike JWST, whose infrared specialties dictated a cryogenic mission, requiring cooling at every stage of testing and assembly, HDST can be operated at room temperature. This is not an insubstantial simplification, and those infrared complications were a major contributor to JWST’s infamous cost and scheduling overruns. Operating at lonely L2, HDST shouldn’t expect to see any servicing missions, but scientists don’t discount the possibility. Hubble’s many servicing missions taught engineers the value in modular parts: instruments and panels that can be removed, replaced, and upgraded easily. Perhaps more likely than human mechanics are robot technicians, an area NASA has been researching for a decade. A robotic servicing mission could be flown for lower cost and safety factors than a human expedition. So engineers will build HDST not expecting any such missions, but prepared if the possibility arises.

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The High Definition Space Telescope represents science’s best bet to take a “pale blue dot” image of a system beyond our own.

THE PATH FORWARD No formal proposal is yet on anyone’s desk. No comprehensive cost analysis or timeline exists. But unless NASA chooses to forgo the space telescope business entirely, HDST will move forward. Twenty years is a long time to wait for your next science project. Put another way, the potential to find out if alien worlds are not just habitable, but inhabited — to answer the fundamental question of whether we are alone in the universe — could be answered within most of our lifetimes. Stacked against millennia of human questioning, the project seems just around the corner. HDST is only one placeholder name for this project. A previous NASA study used the wistful backronym ATLAST, which has come to stand for Advanced Technology LargeAperture Space Telescope. And once upon a time, the same basic concept was called simply the Very Large Space Telescope. In the same way, the James Webb was for many years called the Next Generation Space Telescope, and even Hubble was simply the Large Space Telescope during decades of planning. Eventually, one assumes that the flagship of the 2030s will garner a more auspicious name, likely that of a memorable scientist or public figure. While a commissioning date is still years away and perhaps difficult to visualize past the haze of advisory panels, funding battles, and engineering victories yet to be wrought, Postman offers his choice, based on the telescope’s most fantastic goal of looking for a world that mirrors our own, and a man who made sharing that goal his life’s mission. “You’d want it to be someone who was a true visionary in the field because it takes true vision to accomplish a project like this. I think ‘Carl Sagan’ would be a very nice tribute.” Here’s a toast to Carl, then, and to everyone looking to further our understanding of the universe. The 2030s will be here sooner than you think. D Korey Haynes is a former Astronomy associate editor who earned her Ph.D. studying exoplanets. She’s on Twitter, @weird_worlds

LEFT: AURA. RIGHT: NASA/JPL

30 Doradus in the Large Magellanic Cloud

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Prognosis

The Body Electric

Canan Dagdeviren launched her research group at MIT’s Media Lab earlier this year.

Materials scientist Canan Dagdeviren’s cutting-edge work on flexible sensors is grounded in personal experiences. BY STEPHEN ORNES

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Microbattery

Rectifier

Piezoelectric circuit

PZT nanoribbons

Electric charge is created as ribbons bend and flex

A piezoelectric mechanical energy harvester (above) turns a balloon’s inflation and deflation into electricity. Flexible biocompatible material

Canan Dagdeviren’s biomedical device, which is built on a flexible foundation, would generate enough power to run a pacemaker or other implanted device — no batteries required.

but hasn’t yet made it to the market, would generate enough power to run a pacemaker or other implanted device — no batteries required. Dagdeviren’s energy harvester is built on a flexible foundation. The secret to its success is PZT, or lead zirconate titanate, which is piezoelectric. That means it generates a small electric charge as it flexes and relaxes. Affixed to the lungs, for example, the device changes shape — delivering a steady current — as a person breathes in and out. Dagdeviren’s mother inspired another device. In 2012, her mom complained about how difficult it was to treat dry skin, and Dagdeviren

PHOTOS COURTESY OF CANAN DAGDEVIREN/MIT MEDIA LAB; NANORIBBONS BY ALISON MACKEY/DISCOVER

Can we improve medical devices by designing them to translate the language of the body? Materials scientist Canan Dagdeviren, who just launched a new research group at MIT, thinks so. Ever since she was a child growing up in Turkey, she’s turned tragedy and loss into research that speaks to hope. Her inventions suggest that scientists can harvest electricity from the movements of our organs, pick up the first hints of disease from subtle changes in physiological patterns, or track changes wrought on the brain from neurodegenerative conditions. When Canan (pronounced JAHnaan) was a child in the early 1990s, she learned that her grandfather had died of heart failure at just 28 years old. She promised to herself to do something, anything, to tackle the condition that struck her grandfather. Decades later in early 2014, as part of her doctoral research at the University of Illinois at UrbanaChampaign, she and her collaborators unveiled a tiny biomedical gadget with big implications. Only a few centimeters on a side, the device looks like a sticker and converts energy from the natural movements of internal organs — the beating heart, the expanding or deflating lung, the rising diaphragm — into electricity. It’s not much, but it’s enough juice to power an implanted device like a pacemaker, which regulates irregular heartbeats. “Today’s pacemakers need to be changed every seven years as batteries degrade,” she says. That means an operation. Dagdeviren’s device, which has been tested for safety on cows

immediately imagined how tech might help. As people age, their skin becomes thinner and less elastic; moisturizers restore some of that elasticity. So Dagdeviren created a small, flexible and stretchable sensor that adheres like a sticker and bends with the skin as a person moves. PZT nanoribbons in the device generate small charges that measure skin elasticity, which indicates how well the skin is hydrated and how well a moisturizer is working. During the design process, she consulted with dermatologists, who suggested the device might also identify some skin cancers in their earliest stages. The patent is still pending on the device.

A few companies have expressed interest in bringing it to market, and Dagdeviren says her group is looking for ways to apply the technology to other applications. And wherever it goes, it will always be rooted to her personal history, and her family.

A SPARK OF CURIOSITY Dagdeviren grew up near the sea, so for a change of scenery, her family would trek into nearby forested hills for picnics. One of these outings sparked her interest in science when she was 7 years old, she says. Dagdeviren doesn’t mean “sparked” figuratively. She and her brother had just collected wood for the fire when their mother

pointed out some white rocks with sharp edges, surrounded by flowers. Her mother struck two of those rocks together and produced sparks — showing her daughter the secret for making fire spill from stone. “I loved the idea that you deform this material and create sparks,” says Dagdeviren, 32. “It was very exciting.” That picnic experiment was akin to something she’d already been reading about. A few months earlier, her father gave her a biography of French scientist Marie Curie, two-time winner of the Nobel Prize and a pioneer in the study and understanding of radioactivity. Dagdeviren was inspired, but not in the way her father had expected. She became infatuated with Marie’s husband, Pierre, who Dagdeviren says was her “scientific love.” Pierre and his brother Jacques first described piezoelectricity in 1880. The Greek word piezein means “to squeeze or press,” and piezoelectric materials generate a charge when squeezed or deformed or smashed — like smashing two rocks together to produce a flash. As an undergraduate at Hacettepe University in Ankara, still pondering how to make her own sparks fly, Dagdeviren majored in physics. Her father worried she wouldn’t find a job, that she’d be given a hard time as a woman in the field, but she was undaunted. Dagdeviren studied materials and physics, learned about the science behind all the sparks, and designed her first devices. In 2008, at a materials science conference in Boston, Dagdeviren approached John Rogers, whom she describes as a “king of flexible devices.” At the time, Rogers was at the University of Illinois at UrbanaChampaign. His lab has produced a dizzying array of miniature biocompatible electronic devices that use soft materials, such as plastics and biological tissues. Many stick to the skin like temporary tattoos. Gadgetry out of Rogers’ lab has

July/August 2017 DISCOVER

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Prognosis included everything from “She’s doing things that can’t wireless electronic implants that be replicated with conventional fight a bacterial infection and electronic technology,” says then disappear, to stretchable Rogers, now at Northwestern batteries made of tiny nanowires University. arranged to resemble an Although she’s deeply accordion’s bellows. entrenched in the complexities Rogers is an alum of Bell Labs of nano-electronics, Dagdeviren (now Nokia Bell Labs), which sees her mission as translating in its heyday was renowned for the hidden codes encrypted in turning scientific research into data collected from the body. engineering applications with a The way to decipher those broad societal impact. Rogers codes, she says, is through says he runs his own lab on that continuous monitoring. Most model, encouraging students data measurements — heart rate, Dagdeviren designed a flexible and stretchable sensor that uses to focus on interdisciplinary blood pressure, glucose levels nanoribbons to generate small charges to measure skin’s elasticity. scientific discovery and also — reveal only a momentary This can help monitor subtle changes in the skin. to think about applications. snapshot of a person and don’t Dagdeviren landed at Illinois in Rogers’ capture how those variables fluctuate. lab, and she fit right in. Devices that remain attached to the Many graduate students in the lab, body, outfitted with an unending like Dagdeviren, are driven by personal power source, can observe a stream experiences, says Rogers. “There’s of data, which Dagdeviren says could something that really motivates people make medicine truly personalized. when they’re working on things that Once scientists understand what a could benefit human health,” he says. body says, they can figure out how to “If those devices can save my grandma, keep it running. then it’s not just a device that works — “I create devices that can listen to it has a real, and much deeper impact.” and interpret the body,” she says. In 2014, with her doctorate in hand, After her postdoctoral work with Dagdeviren joined the MIT laboratory Langer, Dagdeviren was offered of Robert Langer, whose work blends her own research group at MIT’s materials science with biotechnology. Media Lab. She spent last winter and His group has designed novel earlier this year assembling a team of approaches to drug delivery systems, as researchers, hiring lab managers and continuously monitor neurological well as new ways to engineer tissue. filing patents on the brain implant. activity and carry out targeted drug “I like people to work on big ideas (She also took a break last December delivery. If it survives extensive lab that I hope change the world, and I to travel to Stockholm to accept a testing and gets to market, it could think they have already changed it,” he prestigious Science & SciLifeLab Prize track the progression of Parkinson’s says. Dagdeviren brought her expertise for Young Scientists.) Dagdeviren has disease or monitor and treat a tumor. to research on brain implants, launching big plans for the brain implant, and she The ideal medical device is collaborations with neuroscientists and is developing ideas for piezoelectriccomfortable, lightweight and other engineers. “She’s been incredible based devices that harvest energy from practically invisible, says Dagdeviren. in doing that kind of [collaborative] outside the body, such as from the Her creations are stretchy, soft and work,” says Langer. “She’s great, motions of knees and elbows. robust. They’re flexible enough to brilliant, innovative.” She calls them “human external laminate sensitive organs, but durable dynamos” — one more example of “HUMAN DYNAMOS” enough to work safely in such a translating the body’s language into Dagdeviren’s most recent design was complicated environment. They improved health. D inspired by the death of a beloved look nothing like the clunky, fragile, Stephen Ornes writes from a backyard shed aunt from a brain tumor. The new beeping, invasive technology we usually in Nashville, Tenn. sensor, implanted in the brain, would associate with lifesaving gadgetry.

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COURTESY OF CANAN DAGDEVIREN/MIT MEDIA LAB

Devices that remain attached to the body, outfitted with an unending power source, can observe a stream of data, which Dagdeviren says could make medicine truly personalized.

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20 Things You Didn’t Know About …

BY GEMMA TARLACH

1 Yoga today is a mainstream fitness activity; 1 in 5 American adults participates in what most people believe is an ancient practice. Surprise: The yoga you’re going to the mat for isn’t that old. 2 What we generally think of as yoga began in late 19th century India, when leaders of an anti-colonialism movement sought to rally their countrymen to their cause. 3 Some of these men saw yoga, then more of a philosophy, as a non-sectarian, indigenous symbol of India that transcended divisions of religion and language: a handy tool to have when you’re trying to unify a nation. 4 These Victorian-era gurus, notably Swami Vivekananda, spread their version of yoga worldwide as a proudly Indian way to achieve a higher level of understanding through contemplation. 5 Modern postural yoga, the practice of actually holding poses, originated with early 20th century guru Krishnamacharya, who taught a mix of gymnastic and wrestling moves, Western calisthenics and hatha yoga, a medieval practice all but lost in India for centuries. 6 It’s in hatha yoga, beginning about the 10th century, that an emphasis on controlling breath and maintaining certain postures arose. But it has little in common with doing a sun salutation at your local gym for tighter abs; medieval hatha yoga’s goals included divination and attaining immortality. 7 What’s really ancient about yoga? The word itself. Around the 15th century B.C., key Sanskrit writings use it to mean an animal’s yoke and also an entire war chariot, yoke and all. 8 Early on, due to the association with chariots used only for fighting, yoga also meant warlike, and people believed a charioteer killed in battle was taken up to the heavens in a divine yoga. Swing low, sweet chariot, indeed. 9 In Sanskrit, yoga has numerous other meanings, including a constellation of stars, the quality of industriousness and even a fraud. 10 We’re not saying there’s anything fraudulent about many of the mental and physical health benefits claimed by practitioners of modern yoga, however. 11 Studies have shown, for example, that postural yoga, along with the practice’s other

components, controlled breath and meditation, can regulate blood pressure, heart rate and respiration. 12 Yoga may be especially helpful to seniors hoping to avoid a fall. In a 2016 meta-analysis of six studies involving individuals over the age of 60, participants showed small improvements in balance and moderate mobility gains after going through postural yoga programs. 13 The practice may even help asthmatics breathe easy. In 2014, a meta-analysis of 14 randomized controlled trials investigating yoga’s effects on asthma found that it appeared to alleviate the chronic inflammatory airway condition better than conventional care. 14 Don’t swap your inhaler for yoga pants just yet, though. The same 2014 study stressed additional research was needed to rule out bias and to understand the mechanism behind yoga’s apparent benefit. 15 A 2016 pilot study of women who described themselves as “psychologically distressed” provided a clue to how yoga works on a molecular level. After eight weeks of instruction, participants had lower levels of certain immune system biomarkers linked to stress. 16 While the researchers emphasized the study sample was too small to draw firm conclusions, it appears yoga may modulate the body’s epigenetic response, which turns certain genes on or off, affecting physical as well as mental health. 17 In a 2014 study, women with treatment-resistant PTSD improved significantly during and after a 10-week yoga program. 18 In fact, by the end of the study, half of the participants no longer met the criteria for a PTSD diagnosis. The researchers believe that practicing yoga may have given the women greater body awareness, which is linked to improved emotional regulation. 19 A study published earlier this year found that self-reported physical health quality was higher among people who practiced yoga in a school or studio setting rather than alone at home. 20 That same study found participants also reported better mental health if they practiced yoga in a group setting. So for maximum benefit, don’t yoga-go it alone. D Gemma Tarlach is senior editor at Discover.

DISCOVER (ISSN 0274-7529, USPS# 555-190) is published monthly, except for combined issues in January/February and July/August. Vol. 38, no. 6. Published by Kalmbach Publishing Co., 21027 Crossroads Circle, P.O. Box 1612, Waukesha, WI 53187-1612. Periodical postage paid at Waukesha, WI, and at additional mailing offices. POSTMASTER: Send address changes to DISCOVER, P.O. Box 62320, Tampa, FL 33662-2320. Canada Publication Agreement # 40010760. Back issues available. All rights reserved. Nothing herein contained may be reproduced without written permission of Kalmbach Publishing Co., 21027 Crossroads Circle, P.O. Box 1612, Waukesha, WI 53187-1612. Printed in the U.S.A.

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