Zapping liquid metal droplets with ultrasound offers a new way to make wiring for stretchy, bendy electronics.

The technique, described in the Nov. 11 Science, adds a new approach to the toolbox for researchers developing circuitry for medical sensors that attach to the skin, wearable electronics and other applications where rigid circuit electronics are less than ideal (SN: 6/1/18).

The researchers began by drawing on sheets of stretchy plastic with lines of microscopic droplets made of an alloy of gallium and indium. The metal alloy is liquid at temperatures above about 16° Celsius.

Though the liquid metal is electrically conductive, the droplets quickly oxidize. That process covers each of them with a thin insulating layer. The layers carry static charges that push the drops apart, making them useless for connecting the LEDs, microchips and other components in electronic circuitry.

By hitting the microspheres with high-frequency sound waves, the researchers caused the microscopic balls to shed even smaller, nanoscopic balls of liquid metal. The tiny spheres bridge the gaps between the larger ones, and that close contact allows electrons to tunnel through the oxide layers so that the droplets can carry electricity.

When the plastic that the drops are printed on is stretched or bent, the larger balls of metal can deform, while the smaller ones act like rigid particles that shift around to maintain contact.

The researchers demonstrated their conductors by connecting electronics into a stretchy pattern of LEDs displaying the initials of the Dynamic Materials Design Laboratory, where the work was done. The team also built a sensor with the conductors that can monitor blood through a person’s skin (SN: 2/17/18).

Flexible electronics applications aren’t new, says materials scientist Jiheong Kang of the Korea Advanced Institute of Science and Technology in Daejeon, South Korea. But there are advantages of the new approach over other designs, he says, such as those that rely on channels filled with liquid metal that can leak if the circuitry is damaged. Liquid metal in the conductors that Kang and colleagues developed stays trapped in the tiny spheres that are embedded in the plastic and remains in place even if the material is torn.

Wires made of liquid metal have often been the go-to conductors for stretchy electronics, says Carmel Majidi, a researcher in mechanical engineering at Carnegie Mellon University in Pittsburgh who was not involved with the new study. Using ultrasound introduces a “novel approach to achieving that conductivity.” Other groups have managed that feat by heating circuits, exposing them to lasers, squishing them or vibrating the circuits to get droplets to connect to each other, he says.

Majidi isn’t convinced that the ultrasound approach is a game changer for flexible circuits. But he says that it’s high time the subject is appearing in a leading journal like Science. “I’m personally really excited to see the field overall, and this particular type of material architecture, is now gaining this visibility.”

DENVER — A hidden landscape riddled with landslides is coming into focus in Yellowstone National Park, thanks to a laser-equipped airplane.

Scientists of yore crisscrossed Yellowstone on foot and studied aerial photographs to better understand America’s first national park. But today researchers have a massive new digital dataset at their fingertips that’s shedding new light on this nearly 1-million-hectare natural wonderland.

These observations of Yellowstone have allowed a pair of researchers to pinpoint over 1,000 landslides within and near the park, hundreds of which had not been mapped before, the duo reported October 9 at the Geological Society of America Connects 2022 meeting. Most of these landslides likely occurred thousands of years ago, but some are still moving.
Mapping Yellowstone’s landslides is important because they can cripple infrastructure like roadways and bridges. The millions of visitors that explore the park each year access Yellowstone through just a handful of entrance roads, one of which recently closed for months following intense flooding.

In 2020, a small aircraft flew a few hundred meters above the otherworldly landscape of Yellowstone. But it wasn’t ferrying tourists eager for up close views of the park’s famous wolves or hydrothermal vents (SN: 7/21/20, SN: 1/11/21). Instead, the plane carried a downward-pointing laser that fired pulses of infrared light at the ground. By measuring the timing of pulses that hit the ground and reflected back toward the aircraft, researchers reconstructed the precise topography of the landscape.

Such “light detection and ranging,” or lidar, data reveal details that often remain hidden to the eye. “We’re able to see the surface of the ground as if there’s no vegetation,” says Kyra Bornong, a geoscientist at Idaho State University in Pocatello. Similar lidar observations have been used to pinpoint pre-Columbian settlements deep within the Amazon jungle (SN: 5/25/22).

The Yellowstone lidar data were collected as part of the 3D Elevation Program, an ongoing project spearheaded by the United States Geological Survey to map the entirety of the United States using lidar.
Bornong and geomorphologist Ben Crosby analyzed the Yellowstone data — which resolve details as small as about one meter — to home in on landslides. The team searched for places where the landscape changed from looking relatively smooth to looking jumbled, evidence that soil and rocks had once been on the move. “It’s a pattern-recognition game,” says Crosby, also of Idaho State University. “You’re looking for this contrast between the lumpy stuff and the smooth stuff.”

The researchers spotted more than 1,000 landslides across Yellowstone, most of which were clustered near the periphery of the park. That makes sense given the geography of Yellowstone’s interior, says Lyman Persico, a geomorphologist at Whitman College in Walla Walla, Wash., who was not involved in the research. The park sits atop a supervolcano, whose previous eruptions blanketed much of the park in lava (SN: 1/2/18). “You’re sitting in the middle of the Yellowstone caldera, where everything is flat,” says Persico.

But steep terrain also abounds in the national park, and there’s infrastructure in many of those landslide-prone areas. In several places, the team found that roads had been built over landslide debris. One example is Highway 191, which skirts the western edge of Yellowstone.

An aerial image of U.S. Highway 191 near Yellowstone shows barely perceptible signs of a long-ago landslide. But laser mapping reveals the structure and extent of the landslide in much greater detail (use the slider to compare images). It’s one of more than 1,000 landslides uncovered by new maps.
It’s worth keeping an eye on this highway since it funnels significant amounts of traffic through regions apt to experience landslides, Bornong says. “It’s one of the busiest roads in Montana.”

There’s plenty more to learn from this novel look at Yellowstone, Crosby says. Lidar data can shed light on geologic processes like volcanic and tectonic activity, both of which Yellowstone has in spades. “It’s a transformative tool,” he says.

It was the rift watched ‘round the world.

In July 2017, after weeks of anticipation, a massive iceberg about the size of Delaware split from the Antarctic Peninsula (SN: 7/12/17). Satellite images show that the orphaned iceberg, known as A68, ultimately disintegrated in the Southern Ocean. Now, researchers say they have pieced together the powerful forces that led to that final breakup.

Polar scientist Alex Huth of Princeton University and colleagues combined observations of the iceberg’s drift with simulations of ocean currents and wind stress. Iceberg A68a, the largest remaining chunk of the original berg, was caught in a tug-of-war of ocean currents, and the strain of those opposing forces probably pulled the iceberg apart, the team reports October 19 in Science Advances.
After A68’s separation from the Larsen C ice shelf, researchers had questions — such as what creatures live on the seafloor in the ice’s dark shadow (SN: 2/8/19). As for the iceberg itself, it took a while to get moving, lingering in the neighborhood for about a year (SN: 7/23/18). By December 2020, satellite images show, the berg had clearly seen some action and was just two-thirds of its original size.
The new simulations suggest how A68a probably met its fate. On December 20, 2020, the long, slender “finger” at one end of the iceberg drifted into a strong, fast-moving current. The rest of the ice remained outside the current. The tension rifted the berg, and the finger sheared off and broke apart within a few days.

Shear stress is a previously unknown mechanism for large iceberg breakup, and isn’t represented in climate simulations, the team says. In the Southern Ocean, the melting of massive bergs can be a large source of cold freshwater to the ocean surface. That, in turn, can have a big impact on ocean circulation and the global climate.

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.

It’s official: The number of planets known beyond our solar system has just passed 5,000.

The exoplanet census surpassed this milestone with a recent batch of 60 confirmed exoplanets. These additional worlds were found in data from NASA’s now-defunct K2 mission, the “second life” of the prolific Kepler space telescope, and confirmed with new observations, researchers report March 4 at arXiv.org.

As of March 21, these finds put NASA’s official tally of exoplanets at 5,005.

It’s been 30 years since scientists discovered the first planets orbiting another star — an unlikely pair of small worlds huddled around a pulsar (SN: 1/11/92). Today, exoplanets are so common that astronomers expect most stars host at least one (SN: 1/11/12), says astronomer Aurora Kesseli of Caltech.
“One of the most exciting things that I think has happened in the last 30 years is that we’ve really started to be able to fill out the diversity of exoplanets,” Kesseli says

Some look like Jupiter, some look — perhaps — like Earth and some look like nothing familiar. The 5,005 confirmed exoplanets include nearly 1,500 giant gassy planets, roughly 200 that are small and rocky and almost 1,600 “super-Earths,” which are larger than our solar system’s rocky planets and smaller than Neptune (SN: 8/11/15).
Astronomers can’t say much about those worlds beyond diameters, masses and densities. But several projects, like the James Webb Space Telescope, are working on that, Kesseli says (SN: 1/24/22). “Not only are we going to find tons and tons more exoplanets, but we’re also going to start to be able to actually characterize the planets,” she says.

And the search is far from over. NASA’s newest exoplanet hunter, the TESS mission, has confirmed more than 200 planets, with thousands more yet to verify, Kesseli says (SN: 12/2/21). Ongoing searches from ground-based telescopes keep adding to the count as well.

“There’s tons of exoplanets out there,” Kesseli says, “and even more waiting to be discovered.”

Smoke rings are being seen in a new light.

Doughnut-shaped structures called vortex rings are sometimes seen swirling through fluids. Smokers can form them with their mouths, volcanoes can spit them out during eruptions and dolphins can blow them as bubble rings. Now, scientists can create the rings with light.

A standard vortex is an eddy in a liquid or gas, like a whirlpool (SN: 3/5/13). Imagine taking that swirling eddy, stretching it out and bending it into a circle and attaching it end-to-end. That’s a vortex ring. These rings travel through the liquid or gas as they swirl — for example, smoke rings float through the air away from a smoker’s head. In the new vortex rings, described June 2 in Nature Photonics, light behaves similarly: The flow of energy swirls as the ring moves.
Optics researcher Qiwen Zhan and colleagues started from a vortex tube, a hurricanelike structure they already knew how to create using laser light. The team used optics techniques to bend the tube into a circular shape, creating a vortex ring.

The light rings aren’t that different from smoke or bubble rings, says Zhan, of the University of Shanghai for Science and Technology. “That’s kind of cool.”

Zhan is interested in seeing whether scientists could create vortex rings out of electric current or a magnetic field. And further study of the light rings might help scientists better understand how topology — the geometry of doughnuts, knots and similar shapes — affects light and how it interacts with matter.

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.