U.S. millennials are rejecting suburbia and moving back to the city. That was a prevailing idea in 2019, when I started as the social sciences reporter at Science News. But when I began digging into a possible story on the phenomenon, I encountered an incoherent mess. Some research showed that suburbs were growing, others that suburbs were shrinking and yet others showed growth in both suburbs and cities.

Unable to make sense of that maze of findings, I shelved the story idea. Then, several months later, I stumbled across a Harvard University white paper explaining that disagreement in the field stems from competing definitions of what distinguishes a city from a suburb. Some researchers define the suburbs as areas falling outside census-designated cities. Others look only for markers of suburbanism, such as a wealth of single-family houses and car-based commutes, the researchers wrote.
I have encountered this type of fuzziness around definitions of all sorts of terms and concepts in the years I’ve covered the social sciences. Sometimes researchers simply assume that their definition of a key concept is the definition. Or they nod briefly at other definitions, and then go forth with whichever one they choose, without much explanation why. Other times, researchers in one subfield choose one definition, and researchers in another subfield choose a different one — each without ever knowing of the other’s existence. It’s enough to drive any reporter to tear their hair out.

“If you look … you will find this morass of definitions and measurements” in the social sciences, says quantitative psychologist Jessica Flake of McGill University in Montreal. My experience was a common one, she assured me.

Definitional morasses exist in other scientific fields too. Biologists frequently disagree about how best to define the word “species” (SN: 11/1/17). Virologists squabble over what counts as “alive” when it comes to viruses (SN: 11/1/21). And not all astronomers are happy with the decision to define the word “planet” in a way that left Pluto out in the cold as a mere dwarf planet (SN: 8/24/21).

But the social sciences have some special challenges, Flake says. The field is a youngster compared with a discipline like astronomy, so has had less time to sort out its definitions. And social science concepts are often inherently subjective. Describing abstract ideas like motivation or feelings can be squishier than describing, say, a meteorite.

It’s tempting to assume, as I did until I began researching this column, that a single, imperfect definition for individual concepts is preferable to this definitional cacophony. And some researchers encourage this approach. “While no suburban definition will be perfect, standardization would increase understanding of how suburban studies relate to each other,” the Harvard researchers wrote in that suburbia paper.

But a recent study taking aim at how we define the middle class showed me how alternative definitions can lead to a shift in perspective.

While most researchers use income as a proxy for class, these researchers used people’s buying patterns. That revealed that a fraction of people who appear middle class by income struggle to pay for basic necessities, such as housing, child care and groceries, the team reported in July in Social Indicators Research. That is, they live as if they are working class.

What’s more, that vulnerable group skews Black and Hispanic, a disparity that arises, in part, because these families of color often lack the generational wealth of white families, says Melissa Haller, a geographer at Binghamton University in New York. So when calamity strikes, families without that financial cushion can struggle to recover. Yet a government or nonprofit organization looking to direct aid toward the neediest families, and relying solely on income-based metrics, would overlook this vulnerable group.

“Depending on what definition you start with, you will see different facts,” says Anna Alexandrova, a philosopher of science at the University of Cambridge. A standardized definition of middle class, for example, could obscure some of those key facts.

In the social sciences, what’s needed instead of conceptual unity, Alexandrova says, is conceptual clarity.

Though social scientists disagree about how to go about solving this problem of clarity, Flake says that failure to tackle the issue jeopardizes the field as much as other crises rocking the discipline (SN: 8/27/18). That’s because how a topic is defined determines the scales, surveys and other instruments used to study that concept. And that in turn shapes how researchers crunch numbers and arrive at conclusions.

Defining one’s key terms and then selecting the right tool is somewhat straightforward when relying on large, external datasets. For instance, instead of using national income databases, as is common in the study of the middle class, Haller and her team turned to the federal government’s Consumer Expenditure Surveys to understand people’s daily and emergency purchases.

But often social scientists, particularly psychologists, develop their own scales and surveys to quantify subjective concepts, such as self-esteem, mood or well-being. Definitions of those terms — and the instruments used to study them — can take on a life of their own, Flake says.

She and her team recently showed how this process plays out in the May-June American Psychologist. They combed through the 100 original studies and 100 replications included in a massive reproducibility project in psychology. The researchers zoomed in on 97 multi-item scales — measuring concepts such as gratitude, motivation and self-esteem — used in the original studies, and found that 54 of those scales had no citations to show where the scales originated. That suggests that the original authors defined their idea, and the tool used to measure that idea, on the fly, Flake says. Research teams then attempted to replicate 29 of those studies without digging into the scales’ sources, calling into question the meaning of their results.

For Flake, the way to achieve conceptual clarity is straightforward, if unlikely. Researchers must hit the brakes on generating new ideas, or replicating old ideas, and instead interrogate the morass of old ones.

She points to one promising, if labor-intensive, effort: the Psychological Science Accelerator, a collaboration of over 1,300 researchers in 84 countries. The project aims to identify big ideas in psychology, such as face perception and gender prejudice, and accumulate all the instruments and resulting data used to make sense of those ideas in order to discard, refine or combine existing definitions and tools.

“Instead of running replications, why don’t we use [this] massive team of researchers who represent a lot of perspectives around the world and review concepts first,” Flake says. “We need to stop replicating garbage.”

I couldn’t agree more.

Wind turbines could offer a double whammy in the fight against climate change.

Besides harnessing wind to generate clean energy, turbines may help to funnel carbon dioxide to systems that pull the greenhouse gas out of the air (SN: 8/10/21). Researchers say their simulations show that wind turbines can drag dirty air from above a city or a smokestack into the turbines’ wakes. That boosts the amount of CO2 that makes it to machines that can remove it from the atmosphere. The researchers plan to describe their simulations and a wind tunnel test of a scaled-down system at a meeting of the American Physical Society’s Division of Fluid Dynamics in Indianapolis on November 21.
Addressing climate change will require dramatic reductions in the amount of carbon dioxide that humans put into the air — but that alone won’t be enough (SN: 3/10/22). One part of the solution could be direct air capture systems that remove some CO2 from the atmosphere (SN: 9/9/22).

But the large amounts of CO2 produced by factories, power plants and cities are often concentrated at heights that put it out of reach of machinery on the ground that can remove it. “We’re looking into the fluid dynamics benefits of utilizing the wake of the wind turbine to redirect higher concentrations” down to carbon capture systems, says mechanical engineer Clarice Nelson of Purdue University in West Lafayette, Ind.

As large, power-generating wind turbines rotate, they cause turbulence that pulls air down into the wakes behind them, says mechanical engineer Luciano Castillo, also of Purdue. It’s an effect that can concentrate carbon dioxide enough to make capture feasible, particularly near large cities like Chicago.

“The beauty is that [around Chicago], you have one of the best wind resources in the region, so you can use the wind turbine to take some of the dirty air in the city and capture it,” Castillo says. Wind turbines don’t require the cooling that nuclear and fossil fuel plants need. “So not only are you producing clean energy,” he says, “you are not using water.”

Running the capture systems from energy produced by the wind turbines can also address the financial burden that often goes along with removing CO2 from the air. “Even with tax credits and potentially selling the CO2, there’s a huge gap between the value that you can get from capturing it and the actual cost” that comes with powering capture with energy that comes from other sources, Nelson says. “Our method would be a no-cost added benefit” to wind turbine farms.

There are probably lots of factors that will impact CO2 transport by real-world turbines, including the interactions the turbine wakes have with water, plants and the ground, says Nicholas Hamilton, a mechanical engineer at the National Renewable Energy Laboratory in Golden, Colo., who was not involved with the new studies. “I’m interested to see how this group scaled their experiment for wind tunnel investigation.”

You might feel a spark when you talk to your crush, but living things don’t require romance to make electricity. A study published October 24 in iScience suggests that the electricity naturally produced by swarming insects like honeybees and locusts is an unappreciated contributor to the overall electric charge of the atmosphere.

“Particles in the atmosphere easily charge up,” says Joseph Dwyer, a physicist at the University of New Hampshire in Durham who was not involved with the study. “Insects are little particles moving around the atmosphere.” Despite this, the potential that insect-induced static electricity plays a role in the atmosphere’s electric field, which influences how water droplets form, dust particles move and lightning strikes brew, hasn’t been considered before, he says.
Scientists have known about the minuscule electric charge carried by living things, such as insects, for a long time. However, the idea that an electric bug-aloo could alter the charge in the air on a large scale came to researchers through sheer chance.

“We were actually interested in understanding how atmospheric electricity influences biology,” says Ellard Hunting, a biologist at the University of Bristol in England. But when a swarm of honeybees passed over a sensor meant to pick up background atmospheric electricity at the team’s field station, the scientists began to suspect that the influence could flow the other way too.

Hunting and colleagues, including biologists and physicists, measured the change in the strength of electric charge when other honeybee swarms passed over the sensor, revealing an average voltage increase of 100 volts per meter. The denser the insect swarm, the greater the charge produced.

This inspired the team to think about even larger insect swarms, like the biblical hordes of locusts that plagued Egypt in antiquity (and, in 2021, Las Vegas (SN: 3/30/21)). Flying objects, from animals to airplanes, build up static electricity as they move through the air. The team measured the charges of individual desert locusts (Schistocerca gregaria) as they flew in a wind tunnel powered by a computer fan. Taking data on locust density from other studies, the team then used a computer simulation based on the honeybee swarm data to scale up these single locust measurements into electric charge estimates for an entire locust swarm. Clouds of locusts could produce electricity on a per-meter basis on par with that in storm clouds, the scientists report.

Hunting says the results highlight the need to explore the unknown lives of airborne animals, which can sometimes reach much greater heights than honeybees or locusts. Spiders, for example, can soar kilometers above Earth when “ballooning” on silk threads to reach new habitats (SN: 7/5/18). “There’s a lot of biology in the sky,” he says, from insects and birds to microorganisms. “Everything adds up.”

Though some insect swarms can be immense, Dwyer says that electrically charged flying animals are unlikely to ever reach the density required to produce lightning like storm clouds do. But their presence could interfere with our efforts to watch for looming strikes that could hurt people or damage property.

“If you have something messing up our electric field measurements, that could cause a false alarm,” he says, “or it could make you miss something that’s actually important.” While the full effect that insects and other animals have on atmospheric electricity remains to be deduced, Dwyer says these results are “an interesting first look” into the phenomenon.

Hunting says this initial step into an exciting new area of research shows that working with scientists from different fields can spark shocking findings. “Being really interdisciplinary,” he says, “allows for these kinds of serendipitous moments.”

Aye-ayes are true champions of nose picking.

A new video offers the first evidence that these nocturnal lemurs of Madagascar stick their fingers up their noses and lick off the mucus. They don’t use just any finger for the job, either. The primates go spelunking for snot with the ultralong, witchy middle finger they typically use to find and fish grubs out of tree bark.

A reconstruction of the inside of an aye-aye’s head based on CT scans shows that this spindly digit probably pokes all the way through the animal’s nasal passages to reach its throat, researchers report online October 26 in the Journal of Zoology.
“This is a brilliant example of how science can serve human curiosity,” says Michael Haslam, a primate archaeologist based in London who was not involved in the new work. “My first take was that it’s a cool — and a bit creepy — video, but [the researchers] have gone beyond that initial reaction of ‘What on Earth?’ to actually explore what’s happening inside the animal.”

The new footage stars Kali, a female aye-aye (Daubentonia madagascariensis) at the Duke Lemur Center in Durham, N.C. “The aye-aye stopped eating and started to pick its nose, and I was really surprised,” says evolutionary biologist Anne-Claire Fabre, who filmed the video. “I was wondering where the finger was going.” An aye-aye is about as big as a house cat, but its clawed middle finger is some 8 centimeters long. And Kali was plunging almost the entire digit up her snout to sample her own snot with dainty licks.

“There is one moment where the camera is [shaking], and I was giggling,” says Fabre, of the Natural History Museum of Bern in Switzerland. Afterward, she asked her colleagues if they had ever seen an aye-aye picking its nose. “The ones that were working a lot with aye-ayes would tell me, ‘Oh, yeah, it’s happening really often,’” says Fabre, who later witnessed the behavior in several other aye-ayes.
This got Fabre and her colleagues curious about how many other primate species have been caught with their fingers in their nostrils. The researchers scoured the literature for past studies and the internet for other videos documenting the behavior.

Unfortunately, “most of the literature that we were finding were jokes,” Fabre says. “I was really surprised, because there is a lot of literature on other types of pretty gross behaviors, such as coprophagy,” or poo eating, among animals (SN: 7/19/21). But between all the bogus articles, the team did find some real reports of primate nose picking, including research done by Jane Goodall in the 1970s.

Aye-ayes are now the 12th known species of primate, including humans, to pick their noses and snack on the snot, the researchers found. Others include gorillas, chimpanzees, bonobos, orangutans and macaques. Nose pickers tend to be primates that have especially good dexterity and use tools.

“The team [has] given us the first map of nose picking across our primate family tree, which immediately raises questions about just how much of this behavior is happening out there, unseen or unreported,” Haslam says. He remembers once seeing a capuchin monkey using a twig or stem to pick its nose (SN: 9/6/15).

“I’m surprised that there aren’t more reports on nose picking, especially from zoos where animals are watched every day,” Haslam adds. “Perhaps our own social stigma around it means that scientists are less likely to want to report nose-picking animals, or it may even be seen as too common to be interesting.”
The fact that so many primate species have been spotted picking their noses and eating the boogers makes Fabre’s team and Haslam wonder whether this seemingly nasty habit has some unknown advantage. Perhaps eating germ-laden boogers boosts the immune system.

For now, untangling the evolutionary origins and potential perks of nose picking will require a more complete census of what species — primate or otherwise — mine and munch on their own mucus.

Some asteroids can barely hold it together.

Rather than solid lumps of rock, ‘rubble pile’ asteroids are loose collections of material, which can split apart as they rotate (SN: 3/16/20). To understand the inner workings of such asteroids, one team of scientists turned to levitating plastic beads. The beads clump together, forming collections that can spin and break up, physicist Melody Lim of the University of Chicago reported March 15 at a meeting of the American Physical Society in Chicago.

It’s an elegant dance that mimics the physics of asteroid formation, which happens too slowly to observe in real-life space rocks. “These ‘tabletop asteroids’ compress phenomena that take place over kilometers [and] over hundreds of thousands of years to just centimeters and seconds in the lab,” Lim said. The results are also reported in a paper accepted in Physical Review X.
Lim and colleagues used sound waves to levitate the plastic beads, which arranged themselves into two-dimensional clumps. Acoustic forces attract the beads to one another, mimicking the gravitational attraction between bits of debris in space. Separate clumps then coalesced similarly to how asteroids are thought to glom onto one another to grow.
When the experimenters gave the structures a spin using the sound waves, the clumps changed shape above a certain speed, becoming elongated. That could help scientists understand why ‘rubble pile’ asteroids, can have odd structures, such as the ‘spinning tops’ formed by asteroids Bennu and Ryugu (SN: 12/18/18).

Eventually, the fast-spinning clumps broke apart. This observation could help explain why asteroids are typically seen to spin up to a certain rate, but not beyond: Speed demons get split up.

Samples of the asteroid Ryugu are the most pristine pieces of the solar system that scientists have in their possession.

A new analysis of Ryugu material confirms the porous rubble-pile asteroid is rich in carbon and finds it is extraordinarily primitive (SN: 3/16/20). It is also a member of a rare class of space rocks known as CI-type, researchers report online June 9 in Science.

Their analysis looked at material from the Japanese mission Hayabusa2, which collected 5.4 grams of dust and small rocks from multiple locations on the surface of Ryugu and brought that material to Earth in December 2020 (SN: 7/11/19; SN: 12/7/20). Using 95 milligrams of the asteroid’s debris, the researchers measured dozens of chemical elements in the sample and then compared abundances of several of those elements to those measured in rare meteorites classified as CI-type chondrites. Fewer than 10 meteorites found on Earth are CI chondrites.
This comparison confirmed Ryugu is a CI-type chondrite. But it also showed that unlike Ryugu, the meteorites appear to have been altered, or contaminated, by Earth’s atmosphere or even human handling over time. “The Ryugu sample is a much more fresh sample,” says Hisayoshi Yurimoto, a geochemist at Hokkaido University in Sapporo, Japan.

The researchers also measured the abundances of manganese-53 and chromium-53 in the asteroid and determined that melted water ice reacted with most of the minerals around 5 million years after the solar system’s start, altering those minerals, says Yurimoto. That water has since evaporated, but those altered minerals are still present in the samples. By studying them, the researchers can learn more about the asteroid’s history.

The fading of a once-vibrant yellow rose reveals how the ravages of time and chemical alteration can dampen the visual power of a painting.

Most of the flowers in Abraham Mignon’s 17th century painting Still Life with Flowers and a Watch seem to leap off the canvas. But one yellow rose, painted with arsenic sulfide–based orpiment pigment, is a flat, jarring element. That wasn’t Mignon’s intention: The rose lost its luster due to the chemical transformation of some of its original bright pigment into colorless lead arsenates, researchers report June 8 in Science Advances.
Paintings conservator Nouchka De Keyser of the Rijksmuseum in Amsterdam and colleagues analyzed the rose using noninvasive techniques including X-ray fluorescence imaging and X-ray powder diffraction (SN: 10/1/21). The team first mapped the lingering traces of arsenic, lead, calcium and other chemical elements in the layers of paint to reveal how Mignon carefully layered paint to create a nearly three-dimensional rose out of light and shadow.

The analyses also revealed two newer crystals on the rose containing both lead and arsenic. Called mimetite and schultenite, the crystals are the product of a series of chemical reactions. First, the reaction of orpiment with light created a highly mobile type of arsenic called arsenolite. That mobilized arsenolite then found its way to an underlying layer of lead white paint and chemically reacted with it to produce the mimetite and schultenite. The crystals lack the bright color of the orpiment — instead, they are colorless and flatten the flower’s appearance.
Science can’t turn back the clock on the chemical transformation to restore the rose’s erstwhile glory — that’s a one-way street. But digital reconstructions made using similar techniques as in the new study could offer several benefits and not just to scientists and art historians, De Keyser says. Not only can such reconstructions reveal now-faded elements in other paintings — they might also appear in museums, allowing visitors a ghostly glimpse of a painting’s true past.

U.S. and Soviet leaders … signed agreements on space, science and technology, health and the environment…. The space agreement … outlines plans for cooperation in fields such as meteorology, study of the natural environment, planetary exploration and space biology.

Update
The 1972 space agreement led to the first inter­national human spaceflight, the Apollo-Soyuz mission, during which Soviet and U.S. crews socialized in space (SN: 7/26/75, p. 52). Apollo-Soyuz encouraged decades of collaboration that continues today on the International Space Station. Now, Russia’s war in Ukraine has prompted many countries to pull back on scientific endeavors with Russia, in space and on Earth (SN: 3/26/22, p. 6). While NASA remains committed to the space station, the head of Russia’s space agency has threatened to end the cooperation in retaliation for sanctions imposed in response to the war. Russia has yet to make moves to abandon the station, though the country has ceased supplying rocket engines to the United States.

The sperm whale is an endangered species. A major reason is that the whale oil is heat-resistant and chemically and physically stable. This makes it useful for lubricating delicate machinery. The only substitute is expensive carnauba wax from the leaves of palm trees that grow only in Brazil … [but] wax from the seeds of the jojoba, an evergreen desert shrub, is nearly as good.

Update
After sperm whale oil was banned in the early 1970s, the United States sought to replenish its reserves with eco-friendly oil from jojoba seeds (SN: 5/17/75, p. 335). Jojoba oil’s chemical structure is nearly identical to that of sperm whale oil, and the shrub is native to some North American desert ecosystems, making the plant an appealing replacement. Today, jojoba shrubs are cultivated around the world on almost every continent. Jojoba oil is used in hundreds of products, including cosmetics, pharmaceuticals, adhesives and lubricants. Meanwhile, sperm whale populations have started to recover under international anti-whaling agreements (SN: 2/27/21, p. 4).

Some thumbnail-sized, brown male spiders in Georgia could be miffed if they paid the least attention to humans and our news obsessions.

Recent stories have made much of “giant” jorō spiders invading North America from eastern Asia, some large enough to span your palm. Lemon yellow bands cross their backs. Bright red bits can add drama, and a softer cheesecake yellow highlights the many joints on long black legs.

The showy giants, however, are just the females of Trichonephila clavata. Males hardly get mentioned except for what they’re not: colorful or big. A he-spider hulk at 8 millimeters barely reaches half the length of small females. Even the species nickname ignores the guys. The word jorō, borrowed from Japanese, translates to such unmasculine terms as “courtesan,” “lady-in-waiting” and even “entangling or binding bride.”
Mismatched sexes are nothing new for spiders. The group shows the most extreme size differences between the sexes known among land animals, says evolutionary biologist Matjaž Kuntner of the Evolutionary Zoology Lab in Ljubljana, Slovenia. The most dramatic case Kuntner has heard of comes from Arachnura logio scorpion spiders in East Asia, with females 14.8 times the size of the males.

With such extreme size differences, mating conflicts in animals can get violent: females cannibalizing males and so on (SN: 11/13/99). As far as Kuntner knows, however, jorō spiders don’t engage in these “sexually conflicted” extremes. Males being merely half size or thereabouts might explain the relatively peaceful encounters.

When it comes to humans, these spiders don’t bother anybody who doesn’t bother them. But what a spectacle they make. “I’ve got dozens and dozens in my yard,” says ecologist Andy Davis at the University of Georgia in Athens. “One big web can be 3 or 4 feet in diameter.” Jorō spiders have lived in northeastern Georgia since at least 2014.
These new neighbors inspired Davis and undergraduate Benjamin Frick to see if the newcomers withstand chills better than an earlier invader, Trichonephila clavipes, their more tropical relative also known as the golden silk orb-weaver. (The jorō also can spin yellow-tinged silk.) The earlier arrival’s flashy females and drab males haven’t left the comfy Southeast they invaded at least 160 years ago.

Figuring out the jorō’s hardiness involves taking the spider’s pulse. But how do you do that with an arthropod with a hard exoskeleton? A spider’s heart isn’t a mammallike lump circulating blood through a closed system. The jorō sluices its bloodlike fluid through a long tube open at both ends. “Think of a garden hose,” says Davis. He has measured heart rates of monarch caterpillars, and he found a spot on a spider’s back where a keen-eyed observer can count throbs.

Female jorō spiders packed in ice to simulate chill stress kept their heart rates some 77 percent higher than the stay-put T. clavipes, tests showed. Checking jorō oxygen use showed females have about twice the metabolic rate. And about two minutes of freezing temperatures showed better female survival (74 percent versus 50 percent). Lab tests used only the conveniently big jorō females, though male ability to function in random cold snaps could matter too.

Plus jorō sightings in the Southeast so far suggest the newer arrival needs less time than its relative to make the next generation, an advantage for farther to the north. The adults don’t need to survive deep winter in any case. Mom and dad die off, in November in Georgia, and leave their hundreds of eggs packed in silk to weather the cold and storms.

Reports on the citizen-observer iNaturalist site suggest that in Georgia, jorō spiders already cover some 40,000 square kilometers, Davis and Frick report February 17 in Physiological Entomology. Sightings now stretch into Tennessee and the Carolinas. But how far the big moms and tiny dads will go and when, we’ll just have to wait and see.