Meet STEVE, a newfound type of aurora that drapes the sky with a mauve ribbon and bedazzling green bling.
This feature of the northern lights, recently photographed and named by citizen scientists in Canada, now has a scientific explanation. The streak of color, which appears to the south of the main aurora, may be a visible version of a typically invisible process involving drifting charged particles, or ions, physicist Elizabeth MacDonald and colleagues report March 14 in Science Advances. Measurements from ground-based cameras and a satellite that passed when STEVE was in full swing show that the luminous band was associated with a strong flow of ions in the upper atmosphere, MacDonald, of NASA’s Goddard Space Flight Center in Greenbelt, Md., and colleagues conclude. But the researchers can’t yet say how a glow arises from this flow.
Part of a project called Aurorasaurus (SN Online: 4/3/15), the citizen scientists initially gave the phenomenon its moniker before its association with ion drift was known. MacDonald and colleagues kept the name, but gave it a backronym: “Strong Thermal Emission Velocity Enhancement.”
Immediately after a 19-year-old shot and killed 17 people and wounded 17 others at a Florida high school on Valentine’s Day, people leaped to explain what had caused the latest mass slaughter.
By now, it’s a familiar drill: Too many readily available guns. Too much untreated mental illness. Too much warped masculinity. Don’t forget those shoot-’em-up video games and movies. Add (or repeat, with voice raised) your own favorite here.
Now the national debate has received an invigorated dose of activism. Inspired by students from the targeted Florida high school, as many as 500,000 people are expected to rally against gun violence and in favor of stricter gun laws on March 24 in Washington, D.C., with sister marches taking place in cities across the world. But a big problem haunts the justifiable outrage over massacres of innocents going about their daily affairs: Whatever we think we know about school shootings, or mass public shootings in general, is either sheer speculation or wrong. A science of mass shootings doesn’t exist.
“There is little good research on what are probably a host of problems contributing to mass violence,” says criminologist Grant Duwe of the Minnesota Department of Corrections in St. Paul. Duwe has spent more than two decades combing through federal crime records and newspaper accounts to track trends in mass killings. Perhaps this dearth of data is no surprise. Research on any kind of gun violence gets little federal funding (SN Online: 3/9/18; SN: 5/14/16, p. 16). Criminologist James Alan Fox of Northeastern University in Boston has argued for more than 20 years that crime researchers mostly ignore mass shootings. Some of these researchers assume that whatever causes people to commit any form of murder explains mass shootings. Others regard mass killings as driven by severe mental disorders, thus falling outside the realm of crime studies.
When a research vacuum on a matter of public safety meets a 24-hour news cycle juiced up on national anguish, a thousand speculations bloom. “Everybody’s an expert on this issue, but we’re relying on anecdotes,” says sociologist Michael Rocque of Bates College in Lewiston, Maine.
Rocque and Duwe published a review of what’s known about reasons for mass public shootings, sometimes called rampage shootings, in the February Current Opinion in Psychology. Their conclusion: not much. Scientific ignorance on this issue is especially concerning given that Rocque and Duwe describe a slight, but not unprecedented, recent uptick in the national rate of rampage shootings. Shooting stats Defining mass public shootings to track their frequency is tricky. A consensus among researchers is emerging that these events occur in public places, include at least four people killed by gunshots within a 24-hour period and are not part of a robbery or any other separate crime, Rocque and Duwe say. Such incidents include workplace and school shootings. Overall, mass public shootings are rare, Duwe says, though intense media coverage may suggest the opposite. Even less obvious is that rampage shootings have been occurring for at least 100 years.
Using Federal Bureau of Investigation homicide reports, Congressional Research Service data on mass shootings and online archives of news accounts about multiple murders, Duwe has tracked U.S. rates of mass public shootings from 1915 to 2017.
He has identified a total of 185 such events through 2017, 150 of which have occurred since 1966. (In 2016, he published results up to 2013 in the Wiley Handbook of the Psychology of Mass Shootings.) In the earliest known case, from 1915, a Georgia man shot five people dead in the street, after killing an attorney he blamed for financial losses, and wounded 32 others. Another lawyer, who came to the crime scene upon hearing gunshots and was wounded by a bullet, ended the rampage when he grabbed a pistol from a hardware store and killed the shooter.
What stands out more than a century later is that, contrary to popular opinion, mass public shooting rates have not ballooned to record highs. While the average rate of these crimes has increased since 2005, it’s currently no greater than rates for some earlier periods. Crime trends are usually calculated as rates per 100,000 people for, say, robberies and assaults. But because of the small number of mass public shootings, Duwe calculates annual rates per 100 million people in the United States.
The average annual rate of mass public shootings since 2010 is about 1.44 per 100 million people. That roughly equals the 1990s rate of 1.41, Duwe finds.
The average annual rate from 1988 to 1993 reached 1.52, about the same as the 1.51 rate from 2007 to 2012. After dropping to just below 1 per 100 million people in 2013 and 2014, rates increased to nearly 1.3 the next three years.
From 1994 to 2004, rates mostly hovered around 1 per 100 million people or below, but spiked to over 2.5 in 1999. That’s the year two teens killed 13 people at Columbine High School in Colorado.
In contrast, rates were minuscule from 1950 to 1965, when only three mass public shootings were recorded. The average annual rate for 1970 to 1979 reached 0.52, based on 13 mass public shootings.
Numbers of people killed and wounded per shooting incident have risen in the last decade, though. Two events in 2012 were particularly horrific. Shootings at a movie theater in Aurora, Colo., and an elementary school in Newtown, Conn., resulted in 40 murders, many of children, and 60 nonfatal gunshot wounds. Whether this trend reflects an increasing use of guns with large-capacity magazines or other factors “is up for grabs,” Duwe says. The unknowns No good evidence exists that either limiting or loosening gun access would reduce mass shootings, Rocque says. Virtually no research has examined whether a federal ban on assault weapons from 1994 to 2004 contributed to the relatively low rate of mass public shootings during that period. The same questions apply to concealed-carry laws, promoted as a way to deter rampage killers. As a gun owner and longtime hunter in his home state of Maine, Rocque calls for “an evidence-based movement” to establish links between gun laws and trends in mass shootings.
Mental illness also demands closer scrutiny, Duwe says. Of 160 mass public shooters from 1915 to 2013, about 60 percent had been assigned a psychiatric diagnosis or had shown signs of serious mental illness before the attack, Duwe has found. In general, mental illness is not linked to becoming violent. But, he says, many mass shooters are tormented and paranoid individuals who want to end their painful lives after evening the score with those they feel have wronged them.
Masculinity also regularly gets raised as a contributor to mass public shootings. It’s a plausible idea, since males committed all but one of the tragedies in Duwe’s review. Sociologist Michael Kimmel of Stony Brook University in New York contends that a sense of wounded masculinity as a result of various life failures inspires rage and even violence. But researchers have yet to examine how any facet of masculinity plays into school or workplace shootings, Rocque says.
Although school shooters often report feeling a desperate need to make up for having been inadequate as men, many factors contribute to their actions, argues clinical psychologist Peter Langman. Based in Allentown, Pa., Langman has interviewed and profiled several dozen school shooters in the United States and other countries. He divides perpetrators into three psychological categories: psychopathic (lacking empathy and concern for others), psychotic (experiencing paranoid delusions, hearing voices and having poor social skills) and traumatized (coming from families marked by drug addiction, sexual abuse and other severe problems).
But only a few of the millions of people who qualify for those categories translate their personal demons into killing sprees. Any formula to tag mass shooters in the making will inevitably round up lots of people who would never pose a deadly threat.
“There is no good evidence on what differentiates a bitter, aggrieved man from a bitter, aggrieved and dangerous man,” says psychologist Benjamin Winegard of Carroll College in Helena, Mont.
Nor does any published evidence support claims that being a bully or a victim of bullying, or watching violent video games and movies, leads to mass public shootings, Winegard contends. Bullying affects a disturbingly high proportion of youngsters and has been linked to later anxiety and depression (SN: 5/30/15, p. 12) but not to later violence. In laboratory studies, youngsters who play violent computer games or watch violent videos generally don’t become more aggressive or violent in experimental situations. Investigators have found that some school shooters, including the Newtown perpetrator, preferred playing nonviolent video games, Winegard says.
He and a colleague presented this evidence in the Wiley Handbook of the Psychology of Mass Shootings. Northeastern’s Fox also coauthored a chapter in that publication.
Still, a small but tragic group of kids lead lives that somehow turn them into killers of classmates or random strangers (SN: 5/27/06, p. 328). If some precise mix of, say, early brain damage, social ineptitude, paranoia and fury over life’s unfair twists cooks up mass killers, scientists don’t know the toxic recipe. And it won’t be easy to come up with one given the small number of mass public shooters to study.
Duwe recommends that researchers first do a better job of documenting the backgrounds of individual mass shooters and any events or experiences that may have precipitated their deadly actions. Then investigators can address broader social influences on mass shootings, including gun legislation and media coverage.
But more than a century after a distraught Georgia man mowed down six of his fellow citizens, research on mass violence still takes a backseat to public fear and outrage. “If we’re bemoaning the state of research,” Duwe says, “we have no one to blame but ourselves.”
Tiny particles of plastic have been found everywhere — from the deepest place on the planet, the Mariana Trench, to the top of Mount Everest. And now more and more studies are finding that microplastics, defined as plastic pieces less than 5 millimeters across, are also in our bodies.
“What we are looking at is the biggest oil spill ever,” says Maria Westerbos, founder of the Plastic Soup Foundation, an Amsterdam-based nonprofit advocacy organization that works to reduce plastic pollution around the world. Nearly all plastics are made from fossil fuel sources. And microplastics are “everywhere,” she adds, “even in our bodies.” In recent years, microplastics have been documented in all parts of the human lung, in maternal and fetal placental tissues, in human breast milk and in human blood. Microplastics scientist Heather Leslie, formerly of Vrije Universiteit Amsterdam, and colleagues found microplastics in blood samples from 17 of 22 healthy adult volunteers in the Netherlands. The finding, published last year in Environment International, confirms what many scientists have long suspected: These tiny bits can get absorbed into the human bloodstream.
“We went from expecting plastic particles to be absorbable and present in the human bloodstream to knowing that they are,” Leslie says. The findings aren’t entirely surprising; plastics are all around us. Durable, versatile and cheap to manufacture, they are in our clothes, cosmetics, electronics, tires, packaging and so many more items of daily use. And the types of plastic materials on the market continues to increase. “There were around 3,000 [plastic materials] when I started researching microplastics over a decade ago,” Leslie says. “Now there are over 9,600. That’s a huge number, each with its own chemical makeup and potential toxicity.”
Though durable, plastics do degrade, by weathering from water, wind, sunlight or heat — as in ocean environments or in landfills — or by friction, in the case of car tires, which releases plastic particles along roadways during motion and braking.
In addition to studying microplastic particles, researchers are also trying to get a handle on nanoplastics, particles which are less than 1 micrometer in length. “The large plastic objects in the environment will break down into micro- and nanoplastics, constantly raising particle numbers,” says toxicologist Dick Vethaak of the Institute for Risk Assessment Sciences at Utrecht University in the Netherlands, who collaborated with Leslie on the study finding microplastics in human blood.
Nearly two decades ago, marine biologists began drawing attention to the accumulation of microplastics in the ocean and their potential to interfere with organism and ecosystem health (SN: 2/20/16, p. 20). But only in recent years have scientists started focusing on microplastics in people’s food and drinking water — as well as in indoor air.
Plastic particles are also intentionally added to cosmetics like lipstick, lip gloss and eye makeup to improve their feel and finish, and to personal care products, such as face scrubs, toothpastes and shower gels, for the cleansing and exfoliating properties. When washed off, these microplastics enter the sewage system. They can end up in the sewage sludge from wastewater treatment plants, which is used to fertilize agricultural lands, or even in treated water released into waterways.
What if any damage microplastics may do when they get into our bodies is not clear, but a growing community of researchers investigating these questions thinks there is reason for concern. Inhaled particles might irritate and damage the lungs, akin to the damage caused by other particulate matter. And although the composition of plastic particles varies, some contain chemicals that are known to interfere with the body’s hormones.
Currently there are huge knowledge gaps in our understanding of how these particles are processed by the human body.
How do microplastics get into our bodies? Research points to two main entry routes into the human body: We swallow them and we breathe them in.
Evidence is growing that our food and water is contaminated with microplastics. A study in Italy, reported in 2020, found microplastics in everyday fruits and vegetables. Wheat and lettuce plants have been observed taking up microplastic particles in the lab; uptake from soil containing the particles is probably how they get into our produce in the first place.
Sewage sludge can contain microplastics not only from personal care products, but also from washing machines. One study looking at sludge from a wastewater treatment plant in southwest England found that if all the treated sludge produced there were used to fertilize soils, a volume of microplastic particles equivalent to what is found in more than 20,000 plastic credit cards could potentially be released into the environment each month.
On top of that, fertilizers are coated with plastic for controlled release, plastic mulch film is used as a protective layer for crops and water containing microplastics is used for irrigation, says Sophie Vonk, a researcher at the Plastic Soup Foundation.
“Agricultural fields in Europe and North America are estimated to receive far higher quantities of microplastics than global oceans,” Vonk says. A recent pilot study commissioned by the Plastic Soup Foundation found microplastics in all blood samples collected from pigs and cows on Dutch farms, showing livestock are capable of absorbing some of the plastic particles from their feed, water or air. Of the beef and pork samples collected from farms and supermarkets as part of the same study, 75 percent showed the presence of microplastics. Multiple studies document that microplastic particles are also in fish muscle, not just the gut, and so are likely to be consumed when people eat seafood.
Microplastics are in our drinking water, whether it’s from the tap or bottled. The particles may enter the water at the source, during treatment and distribution, or, in the case of bottled water, from its packaging.
Results from studies attempting to quantify levels of human ingestion vary dramatically, but they suggest people might be consuming on the order of tens of thousands of microplastic particles per person per year. These estimates may change as more data come in, and they will likely vary depending on people’s diets and where they live. Plus, it is not yet clear how these particles are absorbed, distributed, metabolized and excreted by the human body, and if not excreted immediately, how long they might stick around.
Babies might face particularly high exposures. A small study of six infants and 10 adults found that the infants had more microplastic particles in their feces than the adults did. Research suggests microplastics can enter the fetus via the placenta, and babies could also ingest the particles via breast milk. The use of plastic feeding bottles and teething toys adds to children’s microplastics exposure.
Microplastic particles are also floating in the air. Research conducted in Paris to document microplastic levels in indoor air found concentrations ranging from three to 15 particles per cubic meter of air. Outdoor concentrations were much lower.
Airborne particles may turn out to be more of a concern than those in food. One study reported in 2018 compared the amount of microplastics present within mussels harvested off Scotland’s coasts with the amount of microplastics present in indoor air. Exposure to microplastic fibers from the air during the meal was far higher than the risk of ingesting microplastics from the mussels themselves.
Extrapolating from this research, immunologist Nienke Vrisekoop of the University Medical Center Utrecht says, “If I keep a piece of fish on the table for an hour, it has probably gathered more microplastics from the ambient air than it has from the ocean.” What’s more, a study of human lung tissue reported last year offers solid evidence that we are breathing in plastic particles. Microplastics showed up in 11 of 13 samples, including those from the upper, middle and lower lobes, researchers in England reported.
Perhaps good news: Microplastics seem unable to penetrate the skin. “The epidermis holds off quite a lot of stuff from the outside world, including [nano]particles,” Leslie says. “Particles can go deep into your skin, but so far we haven’t observed them passing the barrier, unless the skin is damaged.”
What do we know about the potential health risks? Studies in mice suggest microplastics are not benign. Research in these test animals shows that lab exposure to microplastics can disrupt the gut microbiome, lead to inflammation, lower sperm quality and testosterone levels, and negatively affect learning and memory.
But some of these studies used concentrations that may not be relevant to real-world scenarios. Studies on the health effects of exposure in humans are just getting under way, so it could be years before scientists understand the actual impact in people.
Immunologist Barbro Melgert of the University of Groningen in the Netherlands has studied the effects of nylon microfibers on human tissue grown to resemble lungs. Exposure to nylon fibers reduced both the number and size of airways that formed in these tissues by 67 percent and 50 percent, respectively. “We found that the cause was not the microfibers themselves but rather the chemicals released from them,” Melgert says.
“Microplastics could be considered a form of air pollution,” she says. “We know air pollution particles tend to induce stress in our lungs, and it will probably be the same for microplastics.”
Vrisekoop is studying how the human immune system responds to microplastics. Her unpublished lab experiments suggest immune cells don’t recognize microplastic particles unless they have blood proteins, viruses, bacteria or other contaminants attached. But it is likely that such bits will attach to microplastic particles out in the environment and inside the body.
“If the microplastics are not clean … the immune cells [engulf] the particle and die faster because of it,” Vrisekoop says. “More immune cells then rush in.” This marks the start of an immune response to the particle, which could potentially trigger a strong inflammatory reaction or possibly aggravate existing inflammatory diseases of the lungs or gastrointestinal tract. Some of the chemicals added to make plastic suitable for particular uses are also known to cause problems for humans: Bisphenol A, or BPA, is used to harden plastic and is a known endocrine disruptor that has been linked to developmental effects in children and problems with reproductive systems and metabolism in adults (SN: 7/18/09, p. 5). Phthalates, used to make plastic soft and flexible, are associated with adverse effects on fetal development and reproductive problems in adults along with insulin resistance and obesity. And flame retardants that make electronics less flammable are associated with endocrine, reproductive and behavioral effects.
“Some of these chemical products that I worked on in the past [like the polybrominated diphenyl ethers used as flame retardants] have been phased out or are prohibited to use in new products now [in the European Union and the United States] because of their neurotoxic or disrupting effects,” Leslie says. What are the open questions? The first step in determining the risk of microplastics to human health is to better understand and quantify human exposure. Polyrisk — one of five large-scale research projects under CUSP, a multidisciplinary group of researchers and experts from 75 organizations across 21 European countries studying micro- and nanoplastics — is doing exactly that.
Immunotoxicologist Raymond Pieters, of the Institute for Risk Assessment Sciences at Utrecht University and coordinator of Polyrisk, and colleagues are studying people’s inhalation exposure in a number of real-life scenarios: near a traffic light, for example, where cars are likely to be braking, versus a highway, where vehicles are continuously moving. Other scenarios under study include an indoor sports stadium, as well as occupational scenarios like the textile and rubber industry.
Melgert wants to know how much microplastic is in our houses, what the particle sizes are and how much we breathe in. “There are very few studies looking at indoor levels [of microplastics],” she says. “We all have stuff in our houses — carpets, insulation made of plastic materials, curtains, clothes — that all give off fibers.”
Vethaak, who co-coordinates MOMENTUM, a consortium of 27 research and industry partners from the Netherlands and seven other countries studying microplastics’ potential effects on human health, is quick to point out that “any measurement of the degree of exposure to plastic particles is likely an underestimation.” In addition to research on the impact of microplastics, the group is also looking at nanoplastics. Studying and analyzing these smallest of plastics in the environment and in our bodies is extremely challenging. “The analytical tools and techniques required for this are still being developed,” Vethaak says.
Vethaak also wants to understand whether microplastic particles coated with bacteria and viruses found in the environment could spread these pathogens and increase infection rates in people. Studies have suggested that microplastics in the ocean can serve as safe havens for germs.
Alongside knowing people’s level of exposure to microplastics, the second big question scientists want to understand is what if any level of real-world exposure is harmful. “This work is confounded by the multitude of different plastic particle types, given their variations in size, shape and chemical composition, which can affect uptake and toxicity,” Leslie says. “In the case of microplastics, it will take several more years to determine what the threshold dose for toxicity is.”
Several countries have banned the use of microbeads in specific categories of products, including rinse-off cosmetics and toothpastes. But there are no regulations or policies anywhere in the world that address the release or concentrations of other microplastics — and there are very few consistent monitoring efforts. California has recently taken a step toward monitoring by approving the world’s first requirements for testing microplastics in drinking water sources. The testing will happen over the next several years.
Pieters is very pragmatic in his outlook: “We know ‘a’ and ‘b,’” he says. “So we can expect ‘c,’ and ‘c’ would [imply] a risk for human health.”
He is inclined to find ways to protect people now even if there is limited or uncertain scientific knowledge. “Why not take a stand for the precautionary principle?” he asks.
For people who want to follow Pieters’ lead, there are ways to reduce exposure.
“Ventilate, ventilate, ventilate,” Melgert says. She recommends not only proper ventilation, including opening your windows at home, but also regular vacuum cleaning and air purification. That can remove dust, which often contains microplastics, from surfaces and the air.
Consumers can also choose to avoid cosmetics and personal care products containing microbeads. Buying clothes made from natural fabrics like cotton, linen and hemp, instead of from synthetic materials like acrylic and polyester, helps reduce the shedding of microplastics during wear and during the washing process.
Specialized microplastics-removal devices, including laundry balls, laundry bags and filters that attach to washing machines, are designed to reduce the number of microfibers making it into waterways.
Vethaak recommends not heating plastic containers in the microwave, even if they claim to be food grade, and not leaving plastic water bottles in the sun.
Perhaps the biggest thing people can do is rely on plastics less. Reducing overall consumption will reduce plastic pollution, and so reduce microplastics sloughing into the air and water.
Leslie recommends functional substitution: “Before you purchase something, think if you really need it, and if it needs to be plastic.”
Westerbos remains hopeful that researchers and scientists from around the world can come together to find a solution. “We need all the brainpower we have to connect and work together to find a substitute to plastic that is not toxic and doesn’t last [in the environment] as long as plastic does,” she says.
A thick sphere of icy debris known as the Oort cloud shrouds the solar system. Other star systems may harbor similar icy reservoirs, and those clouds may be visible in the universe’s oldest light, researchers report.
Astronomer Eric Baxter of the University of Pennsylvania and colleagues looked for evidence of such exo-Oort clouds in maps of the cosmic microwave background, the cool cosmic glow of the first light released after the Big Bang, roughly 13.8 billion years ago. No exo-Oort clouds have been spotted yet, but the technique looks promising, the team reports November 2 in the Astronomical Journal. Finding exo-Oort clouds could help shed light on how other solar systems — and perhaps even our own — formed and evolved. The Oort cloud is thought to be a planetary graveyard stretching between about 1,000 and 100,000 times as far from the sun as Earth. Scientist think that this reservoir of trillions of icy objects formed early in the solar system’s history, when violent movements of the giant planets as they took shape tossed smaller objects outward. Every so often, one of those frozen planetary fossils dives back in toward the sun and is visible as a comet (SN: 11/16/13, p. 14).
But it’s difficult to observe the Oort cloud directly from within it. Despite a lot of circumstantial evidence for the Oort cloud’s existence, no one has ever seen it.
Ironically, exo-Oort clouds might be easier to spot, Baxter and colleagues thought. The objects in an exo-Oort cloud wouldn’t reflect enough starlight to be seen directly, but they would absorb starlight and radiate it back out into space as heat. For the sun’s Oort cloud, that heat signal would be smeared evenly across the entire sky from Earth’s perspective. But an exo-Oort cloud’s warmth would be limited to a tiny region around its star.
Baxter and colleagues calculated that the expected temperature of an exo-Oort cloud should be about –265° Celsius, or 10 kelvins. That’s right in range for experiments that detect the cosmic microwave background, or CMB, which is about 3 kelvins. The team used data from the CMB-mapping Planck satellite to search for areas across the sky with the right temperature (SN Online: 7/24/18). Then, the researchers compared the results with the Gaia space telescope’s ultraprecise stellar map to see if those regions surrounded stars (SN: 5/26/18, p. 5).
Although the astronomers found some intriguing signals around several bright, nearby stars, it wasn’t enough to declare victory. “That’s pretty interesting, but we can’t definitively say that it’s from an Oort cloud or not,” Baxter says.
Other ongoing CMB experiments with higher resolution, like those with the South Pole Telescope and the Atacama Cosmology Telescope in the Chilean Andes, could confirm if those hints of exo-Oort clouds are real.
“It’s a super clever observational idea,” says astronomer Nicolas Cowan of McGill University in Montreal who was not involved in the new work. “Looking for exo-Oort clouds is looking for a signature of these violent histories in other solar systems.”
Cowan has suggested that the cosmic microwave background could also be used to search for a hypothetical Planet Nine in the sun’s Oort cloud (SN: 7/23/16, p. 7). “The very coolest thing would be if we could get measurements of the exo-Oort clouds and find planets in those systems,” he says.
A newly designed airplane prototype does away with noisy propellers and turbines.
Instead, it’s powered by ionic wind: charged molecules, or ions, flowing in one direction and pushing the plane in the other. That setup makes the aircraft nearly silent. Such stealth planes could be useful for monitoring environmental conditions or capturing aerial imagery without disturbing natural habitats below.
The aircraft is the first of its kind to be propelled in this way, researchers report in the Nov. 22 Nature. In 10 indoor test flights the small plane, which weighs about as much as a Chihuahua, traveled 40 to 45 meters for almost 10 seconds at a steady height, even gaining about half a meter of altitude over the course of a flight. Most planes rely on spinning parts to move forward. In some, an engine turns a propeller that pushes the plane forward. Or a turbine sucks in air with a spinning fan, and then shoots out jets of gas that propel the plane forward.
Ionic wind is instead generated by a high-voltage electric field around a positively charged wire, called an emitter. The electricity, often supplied by batteries, makes electrons in the air collide with atoms and molecules, which then release other electrons. That creates a swarm of positively charged air molecules around the emitter, which are drawn to a negatively charged wire. The movement of molecules between the two wires, the ionic wind, can push a plane forward. The current design uses four sets of these wires. Moving ions have helped other things to fly through the air, such as tiny airborne robots. But conventional wisdom said that using the approach to move something through the air as big as an airplane wasn’t possible, because adding enough battery power to propel a plane this way would make it too heavy to stay aloft. (The ion thrusters that propel spacecraft through the vacuum of space work in a very different way and aren’t functional in air.) Attempts to build ion-propelled aircraft in the 1960s weren’t very successful. MIT aeronautics researcher Steven Barrett thought differently. With the right aircraft design and light enough batteries, flight might be possible, his initial calculations suggested. So he and his team used mathematical equations to optimize various features of the airplane — its shape, materials, power supply — and to predict how each version would fly. Then the researchers built prototypes of promising designs and tested the planes at the MIT indoor track, launching them via a bungee system. “The models and the reality of construction don’t always match up perfectly,” Barrett says, so finding the right design took a lot of tries. But in the new study, he and his collaborators report success: 10 flights of the aircraft, which has a 5-meter wingspan and weighs just under 2.5 kilograms.
Barrett’s team isn’t the only one who thought the ionic wind method might take off. Based on calculations done in his lab, “we were confident that this could be done,” says Franck Plouraboue of the Toulouse Fluid Mechanics Institute in France, who wasn’t part of the research. “Here they’ve done it — which is fantastic!”
It’s an example of distributed electric propulsion, says Plouraboue — spreading out the thrust-generating parts of the plane, instead of having one centralized source. That’s a hot area for aircraft research right now. NASA’s X-57 Maxwell plane, for example, bears 14 battery-operated motors along its wings. Increasing the number of propellers makes the plane go farther on the same amount of energy, says Plouraboue, but also increases the drag. With ionic wind propulsion, increasing the number of wires doesn’t increase drag very much.
The plane still needs some upgrades before it’s ready for the real world: Its longest flight was only 12 seconds. And while the aircraft can maintain steady flight for a short time once launched, it can’t actually get off the ground using ionic wind.
Even with improvements, ion-propelled aircraft won’t find their niche as passenger planes, predicts Daniel Drew, an aerodynamics researcher at the University of California, Berkeley, who was not involved in the work. (Drew has designed miniature flying bots that fly using ionic propulsion.) It’s probably not feasible to scale up to something the size of a 747 — there are efficiency trade-offs as planes get bigger, he says. But down the road, the approach might be useful for small, uncrewed planes or drones.
From tales about whales to enthralling scientific histories and the memoir of a frustrated astrophysicist, 2018 was a banner year for science books. Here are Science News’ picks for the titles that should be on any science lover’s bookshelf. Find detailed reviews of many of these books in the links below and in our Editor’s Pick: Favorite books of 2018.
The Truth About Animals Lucy Cooke
A zoologist debunks myths about bats, pandas, Adélie penguins and many other misunderstood creatures, recounting surprising stories from the animal kingdom (SN: 4/14/18, p. 26). Basic Books, $28
Spying On Whales Nick Pyenson
In this captivating look at whales, a paleontologist dives into the animals’ past, exploring how some of Earth’s most intelligent species came to be, and their uncertain future (SN: 7/7/18, p. 29). Viking, $27
Eager Ben Goldfarb
Some people see beavers as pests. But a science writer explains how the dam-building rodents are actually vital ecosystem engineers that can create or expand habitats that benefit the entire wildlife community (SN: 8/4/18, p. 28). Chelsea Green Publishing, $24.95
The Rise and Fall of the Dinosaurs Steve Brusatte
In this memoir, a paleontologist blends experiences from his career with evolutionary science to take readers on an engrossing journey through time, from the beginnings of the dinosaurs to their ultimate extinction. William Morrow, $29.99
The Big Ones Lucy Jones
A seismologist examines past catastrophic natural disasters, including volcanic eruptions, earthquakes and floods, and their impact on culture, politics and society (SN: 3/31/18, p. 26). With the past as a guide, the author warns readers to be prepared for when the next disaster strikes. Doubleday, $26.95
Losing the Nobel Prize Brian Keating
An astrophysicist’s dream of winning a Nobel Prize turned to dust after a promising experiment failed to find the first definitive evidence of cosmic inflation. The experience revealed how the prize can hamper scientific progress (SN: 4/14/18, p. 27). W.W. Norton & Co., $27.95
The Poisoned City Anna Clark
Weaving together history, science and reporting, a journalist explores the public health crisis that began in Flint, Mich., when lead started leaching into residents’ drinking water (SN: 7/21/18, p. 28). Metropolitan Books, $30
The Poison Squad Deborah Blum
A Pulitzer Prize–winning journalist tells the story of a government chemist at the turn of the 20th century and his mission to make food safe in the United States. Penguin Press, $28
Aroused Randi Hutter Epstein
The history of endocrinology makes for a strange and fascinating read, from the scientists who discovered the effects of hormones to the people whose lives have been irrevocably changed by these powerful substances (SN: 7/7/18, p. 28). W.W. Norton & Co., $26.95
Nine Pints Rose George
Blood, the feared as well as revered substance that flows throughout the human body, has a rich historical and scientific past (SN: 10/27/18, p. 28). Metropolitan Books, $30
She Has Her Mother’s Laugh Carl Zimmer
This comprehensive history recounts how researchers have come to understand genetic inheritance. Looking to the future, the author considers risks of gene manipulation (SN: 6/9/18, p. 29). Dutton, $30
Genetics in the Madhouse Theodore M. Porter
Using archival records, a science historian traces the origins of the study of human heredity to insane asylums in the 1800s (SN: 7/7/18, p. 29). Princeton Univ., $35
The Tangled Tree David Quammen
In chronicling the lives of researchers who made important advances in molecular biology and genetics, this book shows how recent findings shake up our understanding of evolution and the tree of life. Simon & Schuster, $30
Poop contains a lot of valuable scientific information. Researchers can monitor microbes, track enzyme activity or hunt for DNA to gather clues about overall health.
There’s so much one can learn from the waste product that microbiologist Aadra Bhatt at the University of North Carolina at Chapel Hill decided there should be a word for that research — something in the same vein as “in vivo” (research done in living animals) and “in vitro” (research done in a petri dish).
After some linguistic digging, she and two colleagues settled on “in fimo.” The term comes from fimus, one of several Latin words for manure or excrement. Their choice won out over the more obvious option of “in feces” because the word feces doesn’t have the same rich scatological legacy — originally it referred to the dregs in a wine cask, Bhatt says.
She and her colleagues, while already using in fimo at meetings and seminars, published their argument online December 13 in Gastroenterology. Compared with the laborious process of pulling together a scientific paper, coming up with this term was “delightful — and it wasn’t particularly drawn out,” Bhatt says. She hopes the word catches on and gains a place in the lexicon for poopetuity.
A few months back, a new storefront appeared in my small Oregon town. Its shelves were packed with tinctures, jars of salve, coffee beans, bath bombs — even beard oil. This motley collection shared a single star ingredient: CBD.
Produced by the cannabis plant, CBD is the straitlaced cousin of marijuana’s more famous component — the THC that delivers a mind-swirling high. CBD, or cannabidiol, has no such intoxicating effects on the mind. Yet the molecule has captured people’s attention in a profound way, sold as a remedy for pain, anxiety, insomnia and other ailments — all without the high.
That neighborhood shop, CBD Scientific, is far from alone in its efforts to sell people on the benefits of CBD, which is found in both marijuana and hemp, two versions of the Cannabis sativa plant. CBD is popping up in products in pet stores, coffee shops and the health and beauty sections of mainstream grocery stores. It’s even being brewed into beer. I left the shop with a $5 bottle of water infused with “5,000,000 nanograms” of CBD.
So far, messages of CBD’s purported health benefits come from people trying to sell CBD products — not from scientists, says Margaret Haney, a neurobiologist who directs the Marijuana Research Laboratory at Columbia University. A gaping chasm separates the surging CBD market and the scientific evidence backing it. While there are reasons to be excited about CBD, the science just isn’t there yet, Haney says. Scientists still don’t know all of the targets CBD hits in the human body, nor what effects it may have, if any. With the exception of tests in people with rare forms of epilepsy, large studies that compare CBD with placebos in people are rare. Much of the existing research was done with cells in the lab or in lab animals, with results that don’t necessarily translate to people.
And there’s always the chance that for some people, CBD’s magic is made not by the compound itself but by a powerful placebo effect; people who expect good outcomes are more likely to see benefits.
Researchers are stepping into the void, lured by promising early data. Small trials are under way looking at the effect of CBD on anxiety, pain, opioid addiction, depression and other health problems. National Institutes of Health funding for CBD studies went from zero in 2014 to an estimated $16 million in 2018. “We’re very interested in CBD,” says Susan Weiss, director of the Division of Extramural Research at the National Institute on Drug Abuse in Bethesda, Md. Still, she urges caution to people eager to try CBD. Because of lax oversight, there’s no telling what’s inside many of those tinctures, oils, rubs and foods for sale online and in stores. “A lot of the products that people are taking may not be what they think,” she says.
Despite the risks and warnings, it seems safe to say that the collective fascination with CBD isn’t going to wear off anytime soon. “People think it’s great for everything,” says cognitive neuroscientist Kent Hutchison of the University of Colorado Boulder. That can’t possibly be true, he says. “But I do think it’s going to be great for some things. We just need to figure out what those things are.”
Mystery molecule Each morning, Samantha Montanaro of Portland, Ore., drops a CBD tincture under her tongue. “I’m kind of testing out my own body with this,” she says. “I’m finding that it really helps with anxiety and stress.”
Montanaro isn’t alone; CBD testimonials are increasingly easy to find. In 2016, Montanaro, now 35, cofounded Tokeativity, a global cannabis community for women. Back then, “CBD wasn’t even a thing,” she says. But the first sparks of the CBD movement caught fire fast. “It’s been pretty crazy to watch how things have evolved,” she says. Some bullish analysts predict that the CBD market in the United States will balloon from hundreds of millions of dollars in 2018 to almost $20 billion by 2022.
Ziva Cooper directs UCLA’s Cannabis Research Initiative and fields a lot of questions about CBD. Her answers invariably disappoint. “When I tell [people] we don’t have very much evidence in people, they’re actually surprised,” she says. When it comes to CBD’s benefits, “there’s actually very little out there to hang our hats on.”
The one exception is for rare forms of childhood epilepsy. Neurologist Elizabeth Thiele of Massachusetts General Hospital in Boston had a young patient who was having over 100 seizures a day. After other treatments had failed, the boy’s parents began searching for a source of CBD oil, which they desperately wanted to try after learning about promising early results in animals. The family flew to England, so the boy could try the CBD formulation made by GW Pharmaceuticals. The child’s results, Thiele says, were remarkable. After a week of CBD, his daily seizures had fallen to single digits. That result ultimately led to clinical trials, one of which included 171 people, mostly children, with Lennox-Gastaut syndrome, a rare and severe seizure disorder. In addition to their normal medication, half of the participants got doses of CBD that were rigorously tested and standardized by the drug’s maker. The other half received their regular treatment plus a placebo. After 14 weeks, the people taking CBD saw a median drop in monthly seizure frequency of about 44 percent; seizures in people who took the placebo dropped almost 22 percent. Thiele and her colleagues published those results in March 2018 in the Lancet.
Side effects were manageable, the researchers found. Diarrhea, sleepiness, poor appetite and vomiting were more likely to occur in the people who took CBD than in those who got the placebo. Along with results from several other trials, those data were strong enough to prompt the U.S. Food and Drug Administration to approve the CBD drug, called Epidiolex, last June. Despite rigorous testing of Epidiolex, big gaps in knowledge on how the drug works in epilepsy remain. Researchers don’t know how CBD tames seizures. Because the molecule comes from cannabis, the early assumption was that CBD latches onto the same chemical receptors that THC connects to, one primarily in the brain and one mainly on immune cells. It turns out, however, that CBD doesn’t seem to hit either of those receptors.
Instead, studies in rats and mice point to two different targets. One, called TRPV1, is known to play a role in pain sensation and maybe epilepsy, too. The other, called GPR55, might change the activity level of nerve cells in the brain, a feat that may be behind CBD’s antiseizure power.
Scientists also don’t know whether CBD keeps working year after year. For some of Thiele’s patients, CBD seems to still be effective after five years of taking the drug, even allowing them to taper off some of their other medications, she says. But data from 92 other patients, presented in December at the American Epilepsy Society’s annual meeting, suggest that CBD’s benefits can start to fade after about seven months on the drug. About a third of the people in the study needed a dose increase after their CBD doses became less effective, researchers from Tel Aviv Sourasky Medical Center reported.
Research on CBD and other ailments lags way behind the epilepsy work. Early experiments, mostly on lab animals but some in small numbers of people, suggest that CBD might fight anxiety, ease schizophrenia symptoms and address pain.
One example: Healthy men who took CBD before a stressful public speaking task were calmer than those who took a placebo, researchers reported in October in the Brazilian Journal of Psychiatry. But only the 15 men who received doses of 300 milligrams were more relaxed. The 27 who took less or more CBD didn’t see benefits. Other types of studies with people, and studies of mice and rats, have turned up antianxiety effects, too. But most of these studies looked at single doses of CBD, not consistent use.
Early evidence of CBD’s promise against schizophrenia comes from a trial of 88 people with the disorder. After six weeks, people who had received a big daily dose of CBD (1,000 milligrams a day) in addition to their normal medication had more improvements in certain symptoms when compared with people who received a placebo. Those results hint that CBD might be a new type of drug for schizophrenia, researchers wrote in March 2018 in the American Journal of Psychiatry.
Studies in lab animals suggest that CBD may help relieve chronic pain. A study appearing in 2017 in Pain found that CBD could block osteoarthritis pain and nerve damage in rats. Hard data for humans are harder to find, but anecdotes abound. Pain clinician Kimberly Mauer of Oregon Health & Science University in Portland and colleagues at the OHSU Comprehensive Pain Center have seen an uptick in patients who say they’re taking CBD. Their experiences are mixed, she says: “About half the patients say they get some benefit, and about half say they didn’t notice anything.”
No easy access To answer the many outstanding questions about CBD’s effects, scientists need access to the compound. But a complex web of U.S. regulations makes that difficult. CBD is subject to rules from both the FDA and the U.S. Drug Enforcement Administration. CBD produced by the marijuana plant remains on the DEA’s list of the most restrictive class of drugs, Schedule 1, alongside LSD, ecstasy and other drugs deemed to have no accepted medical use and high potential for abuse. Access restrictions on industrial hemp, and by extension, the CBD that comes from hemp, were eliminated in the 2018 Farm Bill, signed into law in December. However, regardless of its provenance, CBD is still subject to FDA regulations, as well as any regulations imposed by states. “As easy as it’s gotten for the average person to go legally to buy recreational marijuana and consume it in many states, it’s gotten harder for scientists,” says Haney at Columbia. One of the few approved sources of CBD is a government-sanctioned cannabis facility at the University of Mississippi in Oxford. After she gets the CBD she needs for her studies, Haney is required to meticulously account for every milligram. “I have a gun safe in a locked room that I get into with my fingerprints to store both cannabidiol and marijuana.”
With those restrictions, many scientists just can’t do the studies they want, Hutchison says. “The whole thing is a little bit crazy. People can sell it everywhere, but it’s very difficult for scientists to study its effects in humans.”
Hutchison and colleagues have figured out a legal work-around that doesn’t require researchers to obtain supplies of CBD. The team is avoiding the government-grown cannabis, which can be quite different from the products in circulation, by testing the effects of the cannabis products that people are actually using. To do this, the researchers created a mobile pharmacology lab they call the CannaVan. The tricked-out Dodge contains equipment to study people after they’ve taken a product containing CBD (or THC) that they bought themselves. The researchers are currently collecting data on CBD’s effects on anxiety and pain. Buyer beware FDA rules say that CBD cannot be legally added to food and sold across state lines, sold as a dietary supplement or marketed with claims of treating diseases. But aside from sending some warning letters, the FDA has, so far, let the marketplace run uninhibited. (Some local health authorities, however, are beginning to flex their might, warning restaurants in New York City, for instance, to take CBD off the menu.)
Overall, no one really knows what’s inside the bottles, rubs and coffees for sale. A study published in 2017 in JAMA gives a sense of the problem. Researchers ordered and tested 84 products sold online in 2016 as CBD-containing products. Of those, only 26 were labeled accurately (containing CBD within 10 percent of the claimed amount); 36 of the products had more CBD than their labels said; and 22 products had less. The researchers also found THC in 18 of the 84 samples. Sophie Cloyd is a 30-year-old manager for the CBD company Ablis of Bend, Ore. She is also pregnant. I met her recently at a ski lodge, where she was offering beverage tastes and describing tinctures, oils and lotions. CBD, she says, has helped her manage this pregnancy, her second. She was prescribed the anti-nausea drug Zofran early in her pregnancy, but “the research on Zofran scared me more than the lack of research on CBD,” she says.
Ablis, which makes CBD-infused fizzy drinks and other products, currently gets purified CBD from Colorado, Cloyd says. When the CBD arrives, the company sends it to an independent lab to confirm that it has the right amount of CBD, no pesticides and no THC. But not all CBD sellers test their products.
An unexpected THC dose might not be enough to get a user high, but it could still be a problem, as news reports have begun to point out. To ease his pain from psoriatic arthritis, a school bus driver in Beaverton, Ore., had been taking a daily dose of CBD oil. In early 2018, he failed a periodic drug test with high THC levels, which caused him to lose his job, Portland news channel KATU reported. Even seemingly small amounts of THC can build up in the body with repeated use.
A product might contain even worse surprises. Between December 2017 and January 2018, for example, 52 people fell ill in Utah, with symptoms such as hallucinations, vomiting and seizures, after taking what they thought was CBD. It turned out that the products, many labeled “Yolo CBD oil,” contained a synthetic cannabinoid, and it had poisoned them.
Even if product labels were always accurate, people have no idea of the correct dose of CBD (assuming the right dose would be effective). “You see it marketed in doses like 10 milligrams,” Hutchison says. “Well, 10 milligrams probably does nothing.” For comparison, people who participated in one Epidiolex study took 20 milligrams per kilogram of body weight. To reach that daily dose, I’d need to chug 254 bottles of that 5 million nanogram CBD water I bought — at a cost of $1,270.
Haney makes the same point: “You’re not getting anything resembling an effective dose when you get CBD added to your coffee, or you buy a mint with a little bit of CBD in it,” she says.
There’s even less known about CBD products that you rub on your skin. Scientists don’t know that CBD in creams, oils and ointments actually makes it into the body. “I’m not convinced that anything you’re rubbing on your body with CBD is even getting through,” Haney says. At its heart, the trouble is that most CBD use isn’t backed up by science, Haney says. “I am not against CBD,” she says. In fact, she is about to start a study looking at CBD to treat nerve pain due to chemotherapy in cancer patients. “But I don’t like marketers determining what it’s good for and what it’s not.”
Hype run amok isn’t anything new, says Mauer, the OHSU pain doctor. Consumers try lots of things before the science is definitive — keto diets, for instance, or vitamin D supplements (SN: 2/2/19, p. 16). And even if it turns out that the chemical doesn’t work, the placebo effect might be enough to help reduce symptoms.
So far, the science on CBD isn’t mature enough to weigh in, one way or another. But judging by the number of studies and clinical trials under way, this nascent research field is growing up fast, seeking to quickly fill the space between the science and what people want to know.
This research boom heartens Montanaro. Her message to the scientific community: “I would encourage curiosity,” she says. “I’m not a doctor, and I’m not a scientist, but I certainly know my own body,” and she says that CBD helps her. From her perspective, science has got some catching up to do.
This story appears in the March 30, 2019 issue of Science News with the headline, “The Allure of CBD: People seek health benefits despite lack of evidence.”
For 40 years, they’ve held the front line in Florida’s fight against mosquito-borne diseases. And it turns out that the chickens standing sentinel in cities, marshes, woodlands and residential backyards are clucking good at their job.
Last year, chickens in 268 coops in over a third of Florida’s counties provided scientists weekly blood samples that revealed whether the birds had been bitten by mosquitoes carrying West Nile virus or the Eastern equine encephalitis or St. Louis encephalitis viruses. If a chicken’s blood tests positive for antibodies to one of those viruses, authorities know that the pathogen is circulating. And if enough birds have the antibodies, state officials can ratchet up mosquito-killing measures such as pesticide spraying to help halt disease spread.
The sentinel chicken surveillance programs are “a really good way of monitoring” for certain virus activity, says Thomas Unnasch, a biologist who studies vector-borne diseases at the University of South Florida in Tampa. The birds “are sampling literally hundreds or thousands of mosquitoes every day,” he says. (The chickens can’t keep tabs on dengue or Zika; the mosquitoes carrying those viruses prefer to bite people rather than birds.) In 2018, 833 chickens tested positive for West Nile virus antibodies in Florida, but only 39 people did, according to data from the state’s health department. For Eastern equine encephalitis virus, 154 chickens tested positive in 2018, compared with only three people. Chickens that test positive for the viruses being surveyed don’t transmit them, and people don’t either. Both are considered “dead-end hosts,” meaning that the viral concentration in the blood doesn’t get high enough to infect another mosquito after it bites. Infected cardinals, robins and other backyard birds are the animal reservoirs that help keep the three viruses spreading in the area. Sentinel chickens, by detecting where and when disease-carrying mosquitoes are buzzing, are also providing valuable data on how a virus can spread. Data from 2005 to 2016 revealed that Eastern equine encephalitis virus is active year-round in the Florida panhandle, making the area a source from which the virus moves elsewhere in the state and along the eastern United States, Unnasch and his colleagues report online March 11 in the American Journal of Tropical Medicine and Hygiene.
In people, the viral diseases monitored by the chickens are relatively rare, but can be deadly. The chickens don’t get especially sick, though. “You don’t usually see any symptoms at all,” Unnasch says.
Any chicken whose blood tests positive for the antibodies is removed from the coops since that bird can no longer alert authorities to a new infection. For these chickens, retirement may be spent on a farm, with school or 4-H clubs, or in a backyard coop, depending on the county. The sentinel chicken programs are ready with replacements, raising chicks to supply new birds to signal “where we have a threat to human health,” Unnasch says.
Black holes have been beguiling from the very beginning.
Hinted at as early as the 1780s and predicted by Einstein’s general theory of relativity, they didn’t get the name we know today until the 1960s. Bizarre beasts that squash gobs of matter into infinitely dense abysses, black holes were once thought to be merely a mathematical curiosity.
But astronomers tallied up evidence for black holes’ existence bit by bit, puzzling over where these behemoths live, how they gulp down matter and what their existence means for other physics theories.
For more than a decade, a team of researchers has been engrossed in an ambitious effort to snap a picture of a black hole for the very first time. And now they’ve done it. What better time to think back to black holes’ origins and the journey so far?
