DiscoverJanuary - February 2018的目錄

TWO THINGS WERE INESCAPABLE THIS SUMMER: the Latin single “Despacito,” and the looming eclipse. The first total solar eclipse in the continental United States since 1979, it was also a uniquely American event, with no other countries getting a peek at totality, and at least a partial eclipse visible in all 50 states. As the moon’s shadow crisscrossed the country on Aug. 21, about 154 million American adults saw the eclipse directly, with another 60 million watching electronically — 88 percent of the adult population. It was the most-observed and most-photographed eclipse in history. In a time of so much bitter division, it’s remarkable that an astronomical event just a few minutes long had the power to bring us together, gazing in joy and wonder at the universe. The staffs…

Researchers should tread lightly when it comes to editing the genes of human embryos, according to guidelines handed down in February. The report — issued by dozens of experts convened by the National Academy of Sciences and the National Academy of Medicine — says so-called germline editing, in which genetic changes are passed to future generations, should happen only when there’s no “reasonable alternative” treatment. Doctors already can remove problematic embryos and implant healthy ones using in vitro fertilization. The panel also said the genes of embryos shouldn’t be edited for reasons other than treating or preventing disease or disability.…

FOR YEARS, UNITED STATES public health officials have watched nervously as drug-resistant superbugs marched around the world, killing hundreds of thousands of people. Then in January, a report from the Centers for Disease Control and Prevention revealed that an elderly Nevada woman had died of a bacterial infection that defied even the biggest guns in the infection-fighting arsenal. That’s when many U.S. experts sounded the alarm: Time is running out to stop these deadly pathogens. “We’re somewhere between total panic and a situation we feel confident we can manage,” says James Johnson, a professor of medicine and infectious diseases at the University of Minnesota. Already, superbugs claim 23,000 American lives every year, and over the past eight years, the number of hospitalized children who are resistant to antibiotics has increased…

IN MARCH, PENNSYLVANIA MATHEMATICIANS proved a theorem that rigorously demonstrates congressional districts in their home state are gerrymandered, drawn to give one political party an unfair advantage. Their work, which appeared in The Proceedings of the National Academy of Sciences, supports an ongoing lawsuit demanding better boundaries and joins other mathematical efforts to analyze districting fairness. The method tests districts by applying small, random changes to their boundaries — say, including that neighborhood instead of this one. Such tweaks shouldn’t consistently change election outcomes, assuming the boundaries started out fair. But if the changes lead to alternate outcomes, the mathematicians proved it meant the district was biased from the beginning — in Pennsylvania’s case, in favor of the Republican Party. “It’s important to have rigorous ways of demonstrating [gerrymandering], so…

NASA’S ONGOING JUNO MISSION, revealing what lies beneath Jupiter’s cloud tops and in its atmosphere, has upended many long-held theories about the king of the planets. “In many ways, it’s a new Jupiter,” says Scott Bolton, Juno’s principal investigator at the Southwest Research Institute in San Antonio. Many scientists had thought that by peering underneath Jupiter’s visibly divided outer layers, they would uncover a uniform, well-mixed planet. But according to a May study in Geophysical Research Letters, Juno has spied strong bands of what appears to be ammonia, indicating the planet is churning up material from its depths and implying a more active and variable world. The probe’s data also show polar regions swarming with unforeseen storms. At the same time, Juno is busy sampling Jupiter’s magnetic field, which is…

A GROUP OF RESEARCHERS is one step closer to bringing an unexpected drug into the fray to help treat mental illness: ecstasy. Psychotherapy that incorporates MDMA, the primary ingredient of ecstasy, was designated in August as a Food and Drug Administration “breakthrough therapy” for severe post-traumatic stress disorder. In other words, the therapy is on the fast track toward approval. “If you were to develop a drug to treat PTSD, you’d want it to do exactly what MDMA does,” says Rick Doblin, founder and executive director of the Multidisciplinary Association for Psychedelic Studies (MAPS), which funds and conducts the research. When patients use MDMA, their memories and emotions become more vivid. And in this state, patients experience less fear and anxiety attached to their memories — enough to begin talking…

BEFORE THEY WERE BORN, these mice were astronauts. Or rather, the sperm that made them were. Japanese researchers shipped freezedried mouse sperm to the orbiting International Space Station and stored it there for nine months to find out how microgravity and cosmic radiation would affect mice born from the cells. Upon touching back down to Earth, the rehydrated sperm were used to fertilize mouse eggs (which never left the ground). The resulting pups differed little from the purely Earth-based control mice. The sperm did show signs of mutation, which could have harmed the mice, but cells at the beginning of gestation have a supercharged ability to make repairs, compensating for the damage. The findings, reported in June in the Proceedings of the National Academy of Sciences, offer hope to future…

SCIENTISTS HAVE TAKEN A MAJOR STEP forward toward making artificial blood by creating blood stem cells in the lab. In two studies reported in Naturein May, teams at Harvard University and Weill Cornell Medicine at Cornell University created hematopoietic stem cells (HSCs). These mature into blood’s essential components: platelets, white blood cells and red blood cells. HSCs also generate a lifetime of blood cells, which must be continually replenished. When the body fails to restock, life-threatening forms of anemia, lethal infections or serious bleeding disorders can emerge. To make the HSCs, the Harvard group used human skin cells to create induced pluripotent stem cells (iPSCs), adult cells researchers genetically reprogram to an embryonic-stem-cell state, where they can grow into any kind of cell. Adding seven transcription factors — proteins that…

PROTONS AND NEUTRONS are familiar as tiny solids, but particle accelerators can melt them into what’s called a quark-gluon plasma, or QGP. Studies of the superhot material, first done about a decade ago, have revealed QGP is the hottest, least viscous known liquid and is capable of forming the smallest drop of liquid ever seen. And now, it’s also the fastest known spinning liquid, as reported in August by the STAR collaboration in Nature. In a single second, the authors (an international collaboration working with Brookhaven National Laboratory’s STAR detector) saw the QGP goop rotate a mind-boggling sextillion times — a billion trillions. Getting even small pieces of new information from these experiments is always a challenge, so an experimental measurement of an entirely new feature like rotation speed is…

A 13 MILLION-YEAR-OLD SKULL from Kenya, described in August in Nature, hints at what a common ancestor of all living apes (including humans) looked like. The fossil, from an infant, is the lineage’s most complete skull between 7 million and 17 million years old. The animal had a short snout, similar to that of a gibbon but unlike other apes. Anthropologist and lead author Isaiah Nengo says the fossil offers the best glimpse yet of our distant ancestor: “We now have a face.”…

STEALTH, DISGUISE AND SOME GOOD HIDING SPOTS had previously left these agents undetected. The species that scientists exposed and identified in 2017 had been squirreled away in all kinds of places, from the depths of remote oceans to right under our noses. CODENAME Hoodwinker ocean sunfish NAME Mola tecta COMPROMISED J uly KNOWN TERRITORYSouthern Hemisphere PHYSICAL CHARACTERISTICS Weighs 2 tons; bizarre, flattened body NOTABLE SKILLS/TRAITS EVASION: Researchers first caught wind of M. tecta in 2009, but the fish continued to evade them for years despite its massive size. CODENAME Skywalker hoolock gibbon NAME Hoolock tianxing COMPROMISED January KNOWN TERRITORY Myanmar and southwestern China PHYSICAL CHARACTERISTICSDownturned white eyebrows NOTABLE SKILLS/TRAITS ELITE STATUS: Tucked away in isolated mountains known as sky islands, these rare gibbons have taken careful tracking to find and…

IN MARCH, ASTRONOMERS IN CANADA identified an asteroid unlike any other: It travels the same orbit as Jupiter, but circles the sun in the opposite direction. Only a few other objects in the solar system are known to have such a “wrong way” orbit, and asteroid 2015 BZ509 alone shares its path with a planet. Astronomer Paul Wiegert, from the University of Western Ontario, and colleagues tracked the object during late 2015. They found that its gravitational relationship with the sun and Jupiter keeps it in a safe, stable orbit — and it’s likely been there for around a million years, they reported in Nature. The questions now include figuring out if 2015 BZ509 is more like an icy comet or a rocky asteroid and how it ended up going…

MORE THAN 400,000 AMERICANS are afflicted with multiple sclerosis, an autoimmune disease that disrupts the brain’s neural signals to the body. In March, the Food and Drug Administration approved the drug ocrelizumab to treat not only the milder form of MS, but also the primary-progressive form, for which there was no treatment until now. In both types of MS, immune system cells attack and strip away myelin, the fatty protective sheathing that insulates nerve cells. This interferes with nerve signals, causing muscle weakness, lack of coordination, blurry vision, bowel and bladder problems and foggy thinking. The new-to-market drug takes a novel approach. Whereas traditional MS medications target the immune system’s T-cells, ocrelizumab focuses on destroying the system’s B-cells, which fuel the brain inflammation that causes the disease to worsen. During…

JULES VERNE MIGHT BEdisappointed to learn that we still can’t journey to the center of the Earth. But those curious about what’s down there — metal or monsters? — can take heart from a mathematical proof nearly four decades in the making. The proof, posted online in February, demonstrates that an object’s insides can be mapped exactly without cutting it open. All you need to know is how quickly waves travel between every possible pair of points on the object’s surface. Strictly speaking, the proof applies only to certain mathematically perfect objects. “The Earth is far from mathematical idealization,” says Stanford University’s András Vasy, one of three mathematicians behind the proof. Still, he hopes their work will lead to better tools for geology, which already investigates Earth’s interior by studying…

AMERICAN TREES are marching west, and that’s a surprise to ecologists. As the climate warms, researchers expected many plant species would move farther north — and to higher elevations — as they chase cooler climes. But more trees have actually expanded west over recent decades, according to a May study in Science Advances. A team led by scientists at Purdue University examined about 30 years of U.S. Forest Service data covering 86 types of trees in the eastern United States. In addition to the general westward migration, their study showed the trees aren’t moving in unison. While leafy deciduous trees, such as oak and maple, were more likely to go west, evergreen trees more often pushed north. The researchers say their findings indicate that moisture currently plays a more important…

ANCIENT EGYPT has long been considered the domestic cat’s cradle. But when researchers sequenced DNA from more than 200 ancient cats, they discovered that, while Nile natives formed the most broadly distributed lineage, they were not the first. Paleogeneticist Claudio Ottoni, lead author of the June study in Nature Ecology & Evolution, says, according to DNA records, the first wave of feline domestication occurred about 6,400 years ago in southwest Asia through southeast Europe, but it remained a regional affair. Egyptian cats “conquered the household” sometime after that, Ottoni says. By the eighth century B.C., they’d spread rapidly via trade routes throughout the Mediterranean and across Asia and the Indian Ocean. The study also showed that, unlike domesticated animals seen mostly as sources of meat or labor, cats served as…

IN 1968, AS NAVIGATOR ON APOLLO 8 — the first mission around the moon — Jim Lovell carefully documented his path above the Sea of Tranquility, where NASA would land Apollo 11. He spotted a small, pyramid-shaped mountain near the landing site and named it Mount Marilyn, after his wife. Lovell knew he wouldn’t forget the landmark. Mount Marilyn proved vital on Apollo 11, when Neil Armstrong relied on it for navigation during a harrowing landing. And yet the mountain is among dozens of features named by astronauts but not on official moon maps. For nearly half a century, astronomy’s official nomenclature group, the International Astronomical Union (IAU), wouldn’t make any of the names official; scientists used an asterisk if they cited them. But in July, after multiple applications by…

NEWBORNS TEND to favor facelike patterns, such as top-heavy triangles, and researchers have now shown that third-trimester fetuses have similar preferences. Lighting conditions inside the womb have only recently been explored, so despite extensive research on fetal reaction to other sensory stimuli, visual response had remained unseen until now. In a study published in June in Current Biology, developmental psychologist Vincent Reid of Lancaster University and his team carefully designed an LED array that penetrates maternal tissue, showing the fetus an image of a drifting triangle made of three red dots. When observed with a 4-D ultrasound — in which a 3-D image is in motion — not only were 39 fetuses able to see and track the image, but they also preferred to watch the triangle when it was…

A NEW MATERIAL can suck drinking water out of thin air, no power required. The mesh, called a metal-organic framework, contains tiny spaces perfect for grabbing and holding onto water molecules. Just a couple of pounds of the stuff can draw nearly a gallon of water from the air each day — even in conditions drier than most deserts. Better yet, the sun’s heat is all that’s needed to retrieve the water for drinking. This makes it an attractive option for developing countries with little infrastructure. Researchers have proposed similar water collectors before, but most need electricity or high humidity to function. By further fine-tuning the tiny spaces, the project’s engineers hope one day to harvest even more water. The work, led by researchers at MIT and the University of…

RUTGERS UNIVERSITY NEUROSCIENTIST John McGann, an olfaction researcher, has long been puzzled by claims that people have a feeble sense of smell. In his lab, humans perform as well as rodents and dogs in some tests. Research by his colleagues suggests our species can distinguish a trillion different odors. In a May review published in Science, McGann finally sniffed out the source of the foul-smelling rumor. The main culprit is Paul Broca, a leading 19th-century anatomist, who observed that the brain’s olfactory bulb — where we detect smells — is proportionally puny compared with other mammals. “He accepted the nearuniversal belief in human exceptionalism and looked in the brain for evidence of it,” says McGann. For Broca, a weak sense of smell elevated us above brute animal instinct. His beliefs…

FOR DECADES, SCHOOLCHILDREN ACROSS THE GLOBE were taught our origin story went something like this: An archaic form of Homo sapiens evolved around 200,000 years ago in Africa. By about 100,000 years ago,the population had become anatomically modern humans who, around 50,000 years ago, headed across Eurasia and met up with our distant cousins the Neanderthals (and the closely related Denisovans, not known to science until 2010). Like a game of Jenga, however, researchers have recently been removing bricks and destabilizing that towering timeline. In 2017, a few more bricks came out, and the conventional chronology of our origins finally toppled. What we’re left with: Homo sapiens have been around at least 100,000 years longer than we thought, and left Africa much earlier than we believed. And whenever they ran…

In 1992, some 150 countries signed the U.N. Framework Convention on Climate Change (UNFCCC) with the goal of flatlining greenhouse gases. At the time, the 1987 Montreal Protocol had already kick-started the healing of the ozone hole, so scientists expected the UNFCCC would succeed, too. However, emissions continued to increase. In late 2016, nations of the world convened again. Their optimistic goal: keep global warming below 1.5 degrees Celsius to avoid doomsday scenarios of rising seas, widespread droughts and melting ice. That would mean zero greenhouse emissions by 2050 — an incredible feat. Every country but the United States has since ratified the Paris agreement. By June, reaching that goal seemed questionable after President Donald Trump announced the U.S. would withdraw, though pact rules dictate a four-year wait. European nations,…

IMMUNOTHERAPY, THE HOTTEST FIELD IN CANCER RESEARCH, seeks to supercharge the body’s natural defenses against deadly tumors. Two different approaches are driving the buzz, and one of them got a big boost in August when the Food and Drug Administration approved a “living drug” to treat acute lymphoblastic leukemia (ALL) in children and young adults who’ve stopped responding to chemotherapy. The product, dubbed tisagenlecleucel (pronounced tis-agen- LEK-loo-sell), is the first gene therapy of any kind to be approved in the United States More specifically, tisagenlecleucel is a type of chimeric antigen receptor T cell (CAR-T) therapy, a technique pioneered by immunologist Carl June and colleagues at the University of Pennsylvania. First, an inactivated form of HIV, the virus that causes AIDS, is packed with snippets of custom-designed DNA. Next, T…

ROYAL TYRRELL MUSEUM technician Mark Mitchell estimates he spent 7,000 hours chipping away at rock to uncover this 112 million-year-old dinosaur fossil, put on display at the Alberta museum in May. Described formally in August in Current Biology, the animal’s name, Borealopelta markmitchelli, is a nod to Mitchell’s dedication. The plant-eating, tanklike nodosaur is unusually well preserved, including its hefty body armor, large shoulder spikes and even pieces of soft tissue. Only the animal’s front half was found; its partly exposed innards include the fossilized remnants of a last leafy meal. Don Henderson, the Royal Tyrrell’s curator of dinosaurs, believes that soon after death, the nodosaur’s bloated carcass floated down a river out to the ancient Albertan sea where “eventually the body went pop, and he sank like a stone.”…

PHYSICISTS HAVE FOUNDhundreds of particles made of quarks over the years. Protons and neutrons, for example, are made from “up” and “down” quarks, the two most common and lightest of the six so-called flavors of quarks. But the latest particle discovery, announced at CERN in July, stands out because it’s composed of one up quark and two of an uncommon quark flavor called charm. Theories predicted the new particle — dubbed c+ c+ (pronounced ka-sighsee- see-plus-plus) — more than 30 years ago, but charm quarks are rare and about five times heavier than up quarks, making them unlikely particle ingredients. It took three years of high-energy data collection to find enough c+ c+ particles for physicists to be confident in the discovery. The insights into how the two charm quarks…

3-D PRINTING is now tackling fertility. A team from Northwestern University showed that mice implanted with 3-D-printed ovaries can birth healthy offspring — a medical first that paves the way to scale up the bioprosthetics for humans. The group printed the organs by overlapping pieces of biocompatible gelatin — think of stacking Lincoln Logs. Then, researchers inserted up to 50 follicles into each ovary. These structures produce hormones and also contain eggs. Next, they implanted two ovaries each in seven sterile mice, and mated them with male mice. After a normal gestation of roughly three weeks, three females gave birth to healthy litters. The study, published in Nature Communications in May, also noted that the new moms lactated, evidence of the follicles’ normal hormone production. Though still a long way…

SPOST-TRAUMATIC STRESS DISORDER (PTSD) affects about 24.4 million Americans annually. Now, researchers have detailed evidence that a person’s risk of developing the disorder — which results from experiencing traumatic events like rape and war — is inherited. The work, published in Molecular Psychiatry in April, pooled results from 11 studies to analyze data from over 20,000 volunteers. Previous research suggested genetics might play a role in developing PTSD. But according to senior author and Harvard epidemiologist Karestan Koenen, those findings only inferred heritability. For this work, Koenen and her team examined the entire genomes of those earlier studies’ participants. They found evidence that not only can PTSD be passed down through generations, but also that some related genes are linked to schizophrenia. They further found that European-American women are about…

IN THE HEAT of the 1964 presidential election campaign between Lyndon Johnson and Barry Goldwater, FACT magazine published a fiery headline: “1,189 Psychiatrists Say Goldwater Is Psychologically Unfit to Be President!” Goldwater sued FACT for libel — and won. The American Psychiatric Association (APA), the world’s largest association in the field, reacted to the incident by declaring it “unethical for a psychiatrist to offer a professional opinion unless he or she has conducted an examination and has been granted proper authorization for such a statement.” The 1973 change became known as the Goldwater Rule. The guidelines remained largely uncontroversial for decades, until Donald Trump’s presidential election prompted some mental health professionals to call foul — and go rogue. “After he was elected, people in mental health started getting agitated about…

BACK IN THE 19TH CENTURY, a French criminologist named Alphonse Bertillon invented a technique for recognizing repeat offenders by precisely measuring convicts’ facial features. Fingerprinting eventually supplanted his system, but new research done on macaques shows primate brains can naturally keep track of faces thanks to a kind of bertillonage. The discovery, reported in June in Cell, completely breaks with the standard model of facial recognition, which claims each face you recognize is represented by a single neuron (one cell firing when you see your grandmother, another when you see Jennifer Aniston). Instead, Caltech neuroscientist Doris Tsao showed that individual primate neurons respond to specific facial qualities, such as bone shape and skin color. Inserting electrodes into the brains of two macaques, Tsao worked out which aspects of a face…

CANCER CELLS ARE NOTORIOUSLY ADEPT AT SURVIVAL,even exploiting vulnerabilities within an individual’s DNA to multiply and spread. In July, researchers at the Broad Institute mapped these cancer-linked genetic mutations, called cancer dependencies, for the first time. “For decades, cancer was a black box, and we didn’t know which genes were important,” says research team leader William Hahn of the Dana-Farber Cancer Institute. “The goal with the dependency map is to identify genes of consequence and reverse engineer what their action is, to devise better therapies.” The team uncovered different kinds of dependencies that cancer cells exploit, such as underactive or overactive genes. The Broad Institute’s visualization of the map, simplified here, illuminates both the complexity and interconnectedness of the genetic pathways that fuel tumor growth.…

WHEN TAMIFLU came on the market in 1999, it promised to curtail severe influenza symptoms and even save lives, especially among the frail elderly and the chronically ill. In 2010, in the midst of the H1N1 swine flu pandemic, the World Health Organization (WHO) designated Tamiflu as an “essential medication,” encouraging governments to stockpile it. As a result, the drug has generated over $9 billion in sales worldwide just from government purchases. But Roche, Tamiflu’s maker, had buried the results of several clinical trials. Independent reviews of this unpublished research, in 2012 and 2014, found no evidence that Tamiflu reduced hospitalizations or deaths; it also caused adverse effects. That should have been the end of Tamiflu. But it was not until June that WHO finally downgraded the drug on its…

THE PROTON GOT a little lighter this year, thanks to measurements of its mass that are three times more precise than the best previous effort. This tweak to one of the building blocks of matter, good to 32 parts per trillion, should help refine measurements of other phenomena and test fundamental symmetries in nature. To reweigh the proton, scientists in Germany trapped the particle within magnetic and electric fields. Using phenomenally sensitive detectors from Japan, they compared the particle’s vibrations, which are related to its mass, with the vibrations of a carbon atom (the mass standard-bearer for atoms). Students everywhere hope they don’t have to memorize the mass calculated by the researchers and published in July in Physical Review Letters: 1.007276466583 atomic mass units.…

TODAY’S PAINKILLERStarget the brain and spinal cord. But in April, neuroscientists reported that there might be a way to block pain before it makes it to those central systems. An international team of researchers found that peripheral nerves play an unexpected role in processing pain. Experts had thought these cells merely relayed information to the spinal cord, which integrates other incoming pain signals and sends them to the brain for interpretation. During this process, both the brain and spinal cord use chemical messengers, or neurotransmitters, to turn pain up or down. Scientists believed this ability was limited to the brain and spinal cord. But the team noticed that in rodents, neurons near the spine used a neurotransmitter called gammaaminobutyric acid (GABA) to dial back pain signals before sending them on.…

CYGNUS A IS A GALAXY FAMOUS FOR harboring in its center one of the most active black holes we know of. Astronomers have watched that galaxy for decades, so imagine their surprise when an observatory — New Mexico’s Very Large Array — spotted a new source of radio waves, reported in June in The Astrophysical Journal. The most likely explanation? A second, dormant black hole had awoken, flaming suddenly into view. The two black holes are just 1,500 light-years apart, one of the closest known pairs of supermassive black holes. They are also likely approaching each other and will eventually merge into a single entity. “If our conclusion is correct, this offers a new pathway to understand the process by which large black holes coalesce in galaxy centers,” says lead…

IN 2012, NOBEL LAUREATEFrank Wilczek envisioned a new kind of matter based on a crystal. The ordered framework of a crystal is basically a pattern of atoms that repeats in space. In Wilczek’s time crystals, motion also repeats. Imagine a material with millions of electrons (or tiny bar magnets, if it’s easier to picture) flipping back and forth in unison, like a crystalline clock. Some physicists thought it sounded ridiculous, but now two groups have created versions of the matter in their labs, publishing a pair of papers in Nature in March. At the University of Maryland, 10 ytterbium ions flip around regularly, and at Harvard, it’s a million nitrogen atoms. While the crystals would need to last longer, their ticking could prove a solid way to store information, even…

OUR SUN MAY literally be young at heart. New evidence suggests its core spins nearly four times faster than its outer layers. This finding sheds light on the initial conditions that formed the sun, which spun much faster overall when it was a young star. The window into the sun’s core comes from measuring elusive “gravity waves” that wash back and forth through the solar interior like a sloshing bathtub. (These are unrelated to cosmic gravitational waves; for more on those, see page 13.) But the sun is a noisy place, and global pressure waves — more prominent and numerous — mask the gravity waves. Astronomer Eric Fossat and colleagues used some 16 years of data from the orbiting Solar and Heliospheric Observatory to study these clamoring pressure waves, reporting…

LATE IN THE FIRST CENTURY A.D., a fire struck a neighborhood in the Roman city of Vienne, 20 miles south of Lyon, France. The fire baked the buildings’ bricks and spread so quickly that inhabitants abandoned their belongings. Several other fires struck the area over the following centuries. Two millennia later, the same spot was selected for a housing development. As mandated by the French government, the land underwent archaeological inspection in April by a private company, Archeodunum, which found structures several meters below grade. The intensity of the first conflagration had preserved many aspects of the neighborhood, since fired brick doesn't crumble and heat treatment protects iron from corrosion. Archaeologists found ancient streets, mosaics, shops and multistory houses. Personal belongings like wine jugs and a wooden chest containing a…

SOMEHOW, NAKED MOLE RATS got even weirder in 2017. It turns out the coldblooded, cancer-resistant, pain-immune and conspicuously long-lived rodents also can survive for extended periods of time without oxygen. In tests at the University of Illinois at Chicago, biologists (carefully) deprived naked mole rats of oxygen for 18 minutes; in a separate test, the researchers kept them for more than five hours at dangerously low oxygen levels. Both times, the naked mole rats were unharmed. Most animals need oxygen to survive because it helps convert blood sugar, or glucose, into energy — no oxygen, no life. In the study published in April in Science, researchers found that naked mole rats use glucose this way, too, but it turns out their bodies can switch things up and efficiently metabolize fructose.…

THE UNIVERSAL STRUGGLE: choosing between immediate gratification and long-term rewards. The “marshmallow test,” a psychology classic from the early ’70s, evaluates this skill, called self-regulation, in children. A researcher asks a child to sit alone in a room with a treat. The kid can eat it right away, but waiting 10 to 15 minutes for the researcher to return will grant the child a second treat. Previously, experts tested primarily Western children. But in June, German psychologists published the first marshmallow test using Western and non-Western participants, about 200 kids total. The team found that 4-yearolds from Cameroonian farming families in West Africa bested their German middle-class counterparts. Only 28 percent of the German children earned an extra treat, whereas 70 percent of the Cameroonian children scored a second one;…

WATER IS STRANGE,” says Anders Nilsson, a physicist at Stockholm University in Sweden. It expands when it cools, for example, and it has a strangely high boiling point. In a June paper in the Proceedings of the National Academy of Sciences, Nilsson and his team described a new oddity they discovered: Water can exist in at least two distinct liquid states, each with different physical properties. It takes some coaxing to witness. Nilsson has to bring water well below its freezing point and then fiddle with the pressure, eventually resulting in a liquid that gets less dense as heat is added — proof that liquid water can take on a different physical form. Nilsson even thinks this newly discovered form of water may exist naturally in tiny, shifting pockets within…

FOR HUNDREDS OF MILLIONS OF YEARS, two city-sized stars — each outweighing our sun — circled one another in a fatal dance. They were neutron stars, the collapsed cores left behind after giant stars explode into supernovas. Then, 130 million years ago, the dance ended. Their collision was fast and violent, likely spawning a black hole. And a shudder — a gravitational wave — rippled across the fabric of space-time. Light from the cataclysm followed seconds later. The space-time distortion and the light reached Earth together on Aug. 17, making astronomical history. Astronomers announced the finding Oct. 16. The gravitational wave first reached Italy’s just-finished detector, Advanced Virgo, before stretching and squeezing the two LIGO observatories in the United States. Orbiting space telescopes and instruments on all seven continents turned…

IN JUST A FEW SHORT YEARS, the gene-editing tool CRISPR-Cas9 has infiltrated biology labs around the world. This summer, scientists working in a U.S. lab announced they’d used CRISPR to modify viable human embryos, which were kept alive just a few days. The research is a first in the United States, though scientists in China have conducted similar experiments. This latest effort, led by researchers at Oregon Health and Science University, also succeeded in avoiding unintended effects — something that’s plagued other researchers. The team fixed a mutation by removing a diseasecausing gene from an embryo. The repair, reported in August in Nature, corrected an inheritable heart condition, passed down by the embryo’s father, the study’s lone sperm donor. “This embryo gene correction method — if proven safe — can…

IMAGINE LOOKING UP at the night sky and seeing planets looming larger than our moon. It sounds like science fiction, but astronomers discovered it could be reality for the TRAPPIST-1 system, which boasts seven Earth-sized worlds — a record. Some orbit almost as close to each other as the moon is from Earth. In May 2016, members of the Belgian TRAPPIST team announced their small telescope had turned up three potentially habitable planets orbiting a star just 40 light-years away. Then they turned to NASA’s Spitzer Space Telescope to get more detail, and it revealed there were actually a whopping seven. Three orbit in the star’s conservative habitable zone, the region where liquid surface water might exist. The results appeared in Nature in February. TRAPPIST-1 is a cool red dwarf…

FOR THE PAST 130 YEARS, paleontologists divided dinosaurs into two groups, based on a handful of anatomical features — a split they believe occurred early in the animals’ evolution more than 230 million years ago. The “lizard-hipped” saurischians comprised meat-eating theropods such as T. rex and long-necked, herbivorous sauropodomorphs, such as Diplodocus. On the other side of the divide, “birdhipped” ornithischians included beaked plant-eaters such as Triceratops. In March, however, Nature published a proposal that trashes the traditional family tree. Instead, researchers placed theropods with ornithischians, forming a group called Ornithoscelida, and put sauropodomorphs with the early and primitive herrerasaurs. “Our new hypothesis has lots of exciting implications about when and where dinosaurs may have originated, as well as when feathers may have evolved,” says University of Cambridge paleontologist Matthew…

MORE THAN 100,000 Americans need an organ transplant, and roughly 20 die daily while waiting. Since the early 20th century, scientists have envisioned a workaround in which we could use pig organs, but those so-called xenotransplants have never been humancompatible. This year, bioengineers at Harvard University and technology startup eGenesis reached an important milestone in making that vision reality. Pigs carry retroviruses, which replicate by permanently inserting their genes in the DNA of a host species. And in lab experiments, these porcine endogenous retroviruses (PERVs) tended to leap from pig to human cells. In a paper published in August in Science, scientists addressed this potential biohazard by knocking out the retroviral DNA with the gene editing technology CRISPR-Cas9. After cloning PERV-free embryos, the team implanted them in sows and raised…

MUCH OF ANTARCTICA is covered with a thick sheet of ice that obscures what’s below, and it’s tempting to consider the continent as geologically frozen as its landscape. But in the land of snow and ice, there’s a hidden fire. Reporting their findings in May, geology student Max Van Wyk de Vries and his colleagues at the University of Edinburgh used radar surveys to reveal 91 previously unidentified volcanoes in the West Antarctic Rift System, an area where plate tectonics are tearing the continent apart. Some seem to have erupted in the last few millennia. Scientists aren’t sure how, or even if, the volcanoes will affect the overlaying ice sheet. Another pressing question: Will eruptions increase in Antarctica as the ice thins, similar to Iceland after the Ice Age? What’s…

EADWEARD MUYBRIDGE’S“The Horse in Motion” was an early demonstration of stop-motion illustration. In keeping with his pioneering spirit, Harvard University researchers have re-created the images by storing data in living bacteria. The results were published in Nature in July. Geneticist Seth Shipman and his team translated the pixels of Muybridge’s moving picture into a code made from the As, Ts, Gs, and Cs of DNA. Then, using the CRISPR-Cas gene-editing tool, they spliced sequences corresponding to individual video pixels into the genome. The bacteria strung these snippets together in order and stored them in its DNA, letting scientists replay the video. Now that they’ve shown it’s possible to encode and retrieve information sequentially in bacteria, Shipman hopes to create “molecular recorders” — genetically engineered cells with a time log of…

SPERM COUNTS have plunged 52.9 percent in the past 39 years in North America, Europe, Australia and New Zealand, according to a July analysis in Human Reproduction Update. This trend is worrisome because, besides affecting male fertility, men with lower sperm counts also have higher rates of heart disease and cancer. They also die at younger ages. The analysis involved 185 studies of 42,935 men conducted between 1973 and 2011. (Men in other parts of the world weren’t included because solid data isn’t available.) Environmental factors are the likely culprits. For example, men with low sperm counts might have been exposed in utero to cigarette smoke or chemicals that disrupt crucial hormone levels. “This is the canary in the coal mine,” says Shanna H. Swan, a study co-author at Icahn…

IF OUR DNA is a blueprint, then RNA is the messenger, ferrying instructions for biological tasks to our cells. If you’re an octopus, though, that message can change en route. An international research team found that octopuses can edit their RNA, albeit unintentionally. This ability may offer some of the same adaptive benefits as natural selection, but on an individual level. Writing in April in the journal Cell, the scientists said this ability allows octopuses to reinterpret their DNA in a way that could grant them new traits, like better cold adaptation. There were also hints that these RNA changes made the animals smarter. Octopuses are infamously clever, and such RNA editing could help explain why. Adding weight to this theory is evidence that nautiluses, a closely related shelled cephalopod…

DESPITE WHAT JURASSIC PARK TOLD YOU, DNA doesn’t last forever. Even though mummies can preserve human tissues for millennia, most useful DNA doesn’t make it. That’s why it was a pleasant surprise when archaeologists announced in May they’d found three full genomes from Egyptian mummies. Initial analyses are already suggesting that ancient Egyptians had much more Middle Eastern ancestry than Egyptians do today, and more insights likely await. Working with 151 mummies recovered from a large burial site near Cairo, German researchers sampled bones, teeth and soft tissue to sift out any viable DNA sequences. In all, they recovered 90 mitochondrial sequences — the tiny portion of our genome contained within mitochondria — in addition to the three full genomes, as detailed in a paper in Nature. The mummies were buried between…

THIS PAST SUMMER, paleontologists announced a new contender for largest dinosaur: Patagotitan mayorum. The 100 million-year-old giant was a type of plant-eating, long-necked sauropod called a titanosaur, and is likely the largest creature known to have walked the planet. An international group of researchers described the animal in August in the journal Biological Sciences,after analyzing the partial skeletons of six individuals unearthed in Argentina in 2014. They estimate the animal grew up to 122 feet long and weighed roughly 69 tons — about the same as 10 fully grown male African elephants, today’s largest land animal. Phil Mannion, a sauropod expert at Imperial College London who was not involved with the study, praises the find. “Whether or not Patagotitanis the largest known dinosaur,” he says, “it fills an important gap…

HEAT WAVES CAN KILL PEOPLE,and by 2100, half of Earth’s population could experience 20 days or more of life-threatening heat every year. And that’s if humans drastically reduce their CO2 footprint. In the worst-case scenario — if greenhouse gas emissions keep growing — some 75 percent of humans could feel that deadly heat, according to a June paper published in Nature Climate Change. The research team, led by University of Hawaii scientists, analyzed future climate trends by looking at studies of past heat waves. They found that combinations of heat and humidity exceeding our ability to cool ourselves with sweat could regularly threaten large swaths of humanity by 2100. What’s more, the analysis indicates that many regions near the tropics in particular — where billions of people live — would…

TO PROTECT THEMSELVESagainst predatory birds, some slugs have evolved to produce a defensive mucus that secures them to virtually any surface. Strong, stretchy and effective even in wet environments, the adhesive could be useful for surgeons struggling to plug and patch patients’ slippery organs — if only the substance could be efficiently manufactured. Harvard University bioengineer Jianyu Li has now mimicked this slug mucus in the lab, making synthetic glues using extracts from shrimp shell and algae. “Our adhesives are engineered to copy the essential biochemical and microstructural characteristics of the mucus,” he says. Like defensive mucus, Li’s concoctions can bond surfaces chemically, physically and electrostatically. Initial tests, reported July in Science, have demonstrated effective adhesion to animal hearts and livers, as well as cartilage and arteries. The slime that…

ACCORDING TO AZTEC BELIEFS, gods died to create the world, and people owed them a debt to be repaid through large-scale human sacrifices. Accounts by 16th-century Spanish colonists painted a grisly picture: miles-long lines of victims awaiting such a fate, and more than 100,000 severed heads strung along a tzompantli, or skull rack, at Templo Mayor, the Great Temple. The colonists exaggerated the death tolls, but sacrifices and tzompantli were real. Some of the victims resurfaced in July, when archaeologists uncovered a tower made from more than 650 human skulls near the ruins of Templo Mayor in Mexico City. Skulls were likely added to the tower after public display on the nearby tzompantli, indicated by rows of 10-inch holes that once held wooden posts supporting the skull rack. Of the…

AS A FAINT, YOUNG SUNshone on our freshly formed Earth around 4 billion years ago, primitive creatures, each less than half the width of a human hair, were thriving around volcanic vents. That’s the conclusion of an international team of geoscientists who announced in March in Nature they’d unearthed these creatures’ remains. The microfossils, potentially the oldest discovered, were locked inside rocks in remote northern Canada that were 3.8 billion to 4.3 billion years old — roughly when scientists think life started. But that wasn’t the only finding this year that suggested life on Earth is older than we thought. In September, Japanese geoscientists, publishing in Nature, said they’d also found traces of 3.95 billionyear- old life-forms in different northern Canadian rocks. Some critics doubt the age claims of both…

EARLY BIRD OR NIGHT OWL, you can thank evolution: Staggered natural sleep patterns, or chronotypes, may have kept our species alive. Having a few members of a group awake at all times can protect everyone from predators and other threats. This idea, known as the sentinel hypothesis, was proposed in the 1960s and demonstrated in some birds and rodents. In July, in Proceedings of the Royal Society B, researchers described the first evidence for the sentinel hypothesis in humans. The team used wrist monitors to track the sleep patterns of 33 members of Tanzania’s Hadza people, whose environment and hunter-gatherer lifestyle are similar to those of early humans. The findings: During more than 220 hours of data collection, there were only 18 one-minute increments when all participants were soundly asleep.…

DEEP BRAIN STIMULATION is a valuable therapeutic tool, allowing experts to target specific brain cells to help treat disorders like Parkinson’s disease and obsessive-compulsive disorder. The catch? Activating specific buried neurons requires sticking electrodes directly into the brain — a technique that involves risky surgery. In June, an international team of researchers reported it had developed a noninvasive way to stimulate neurons deep in the brain using electrodes placed on the scalp. Their method relies on what’s called temporal interference. Essentially, the electrodes are set at two different frequencies that are normally too high to activate neurons. But in the spots where the currents cross paths, that interaction generates a lower frequency to which neurons respond. Since these slivers of low-frequency currents depend on the electrodes’ placement, researchers can easily…

INDIA’S DECCAN TRAPS — geologically defined as a large igneous province (LIP) — formed when a massive volcanic eruption spread lava over hundreds of thousands of square miles. The event also released toxic gases and altered Earth’s temperature, helping to kill off the dinosaurs some 66 million years ago. But the Deccan Traps are not unique. Remnants of similar LIPs, spawned during world-altering eruptions, exist from Siberia to Australia. In March, researchers released a new map of them, including previously unknown sites. To create the map, Carleton University geologist Richard Ernst documented telltale signs of LIPs: large fractures in Earth’s crust. He then dated the volcanic events using rock samples from colleagues. “My lesson from this is that the Earth can go through dramatic changes,” he says. “The planet doesn’t…

COMMUNICATING IN AMERICAN SIGN LANGUAGE takes considerable dexterity. Even the letters of the alphabet, gesticulated with one hand, require precise coordination of all five fingers. Already looking for ways to develop low-cost electronic gloves to interact with computers, University of California, San Diego, nanoengineer Darren Lipomi saw ASL letters as the perfect proof of concept for a smart glove. He and colleagues described the completed project in a paper in July in PLOS ONE. Lipomi’s glove — made entirely from offthe- shelf components at a cost of under $100 — calculates joint position based on electrical fluctuations in stretch-sensitive polymers. With an accelerometer reading hand movement and a microprocessor, the glove can translate ASL letters into characters on a computer screen. For Lipomi, understanding sign language is only the first…

WITH A PUFF OF AIR, this vine-inspired robot can nose itself into a number of tight situations. Created by researchers at Stanford University and reported in July, the contraption is essentially a plastic tube connected to an air pump. It moves by turning itself inside out, drawing material from the inside to extend the tube farther — similar to those water snake toys from the ’90s. Another version of the bot has a chamber on either side; inflating just one enables it to turn. The tube-bot’s design enhances its versatility, as its outer layer remains stationary rather than needing to slide over surfaces. In early tests, the robot could extend from a compressed length of just 11 inches to over 200 feet and could carry objects inside it, such as…