Slow-motion large land snails made for easy catching and good eating as early as 170,000 years ago.

Until now, the oldest evidence of Homo sapiens eating land snails dated to roughly 49,000 years ago in Africa and 36,000 years ago in Europe. But tens of thousands of years earlier, people at a southern African rock-shelter roasted these slimy, chewy — and nutritious — creepers that can grow as big as an adult’s hand, researchers report in the April 15 Quaternary Science Reviews.
Analyses of shell fragments excavated at South Africa’s Border Cave indicate that hunter-gatherers who periodically occupied the site heated large African land snails on embers and then presumably ate them, say chemist Marine Wojcieszak and colleagues. Wojcieszak, of the Royal Institute for Cultural Heritage in Brussels, studies chemical properties of archaeological sites and artifacts.

The supersized delicacy became especially popular between about 160,000 and 70,000 years ago, the researchers say. Numbers of unearthed snail shell pieces were substantially larger in sediment layers dating to that time period.

New discoveries at Border Cave challenge an influential idea that human groups did not make land snails and other small game a big part of their diet until the last Ice Age waned around 15,000 to 10,000 years ago, Wojcieszak says.

Long before that, hunter-gatherer groups in southern Africa roamed the countryside collecting large land snails to bring back to Border Cave for themselves and to share with others, the team contends. Some of the group members who stayed behind on snail-gathering forays may have had limited mobility due to age or injury, the researchers suspect.

“The easy-to-eat, fatty protein of snails would have been an important food for the elderly and small children, who are less able to chew hard foods,” Wojcieszak says. “Food sharing [at Border Cave] shows that cooperative social behavior was in place from the dawn of our species.”

Border Cave’s ancient snail scarfers also push back the human consumption of mollusks by several thousand years, says archaeologist Antonieta Jerardino of the University of South Africa in Pretoria. Previous excavations at a cave on South Africa’s southern tip found evidence of humans eating mussels, limpets and other marine mollusks as early as around 164,000 years ago (SN: 7/29/11).

Given the nutritional value of large land snails, an earlier argument that it was eating fish and shellfish that energized human brain evolution may have been overstated, says Jerardino, who did not participate in the new study.
It’s not surprising that ancient H. sapiens recognized the nutritional value of land snails and occasionally cooked and ate them by 170,000 years ago, says Teresa Steele, an archaeologist at the University of California, Davis who was not part of the work. But intensive consumption of these snails starting around 160,000 years ago is unexpected and raises questions about whether climate and habitat changes may have reduced the availability of other foods, Steele says.

Researchers have already found evidence that ancient people at Border Cave cooked starchy plant stems, ate an array of fruits and hunted small and large animals. The oldest known grass bedding, from around 200,000 years ago, has also been unearthed at Border Cave (SN: 8/13/20).

Several excavations have been conducted at the site since 1934. Three archaeologists on the new study — Lucinda Backwell and Lyn Wadley of Wits University in Johannesburg and Francesco d’Errico of the University of Bordeaux in France — directed the latest Border Cave dig, which ran from 2015 through 2019.

Discoveries by that team inspired the new investigation. Excavations uncovered shell fragments of large land snails, many discolored from possible burning, in all but the oldest sediment layers containing remnants of campfires and other H. sapiens activity. The oldest layers date to at least 227,000 years ago.

Chemical and microscopic characteristics of 27 snail shell fragments from various sediment layers were compared with shell fragments of modern large African snails that were heated in a metal furnace. Experimental temperatures ranged from 200° to 550° Celsius. Heating times lasted from five minutes to 36 hours.

All but a few ancient shell pieces displayed signs of extended heat exposure consistent with having once been attached to snails that were cooked on hot embers. Heating clues on shell surfaces included microscopic cracks and a dull finish.

Only lower parts of large land snail shells would have rested against embers during cooking, possibly explaining the mix of burned and unburned shell fragments unearthed at Border Cave, the researchers say.

The battle over the heft of a hard-to-detect particle is heating up. What’s at stake? Only the leading theory describing all known matter in the universe.

A recalculation of the mass of an elementary particle, the W boson, has increased the tension between measurements from competing particle collider experiments. The ultimate outcome could bolster the standard model of particle physics, which describes the fundamental forces and quantum bits that make up everything we see in the cosmos. Or it could reveal signs of the standard model’s breakdown, depending on which lab’s answer prevails.
A reanalysis of old data from the Large Hadron Collider’s ATLAS experiment yields a W boson mass of about 80,360 million electron volts, or MeV. Researchers with the experiment, at CERN in Geneva, reported the measurement March 23 at the Rencontres de Moriond conference in La Thuile, Italy. The revised value is closely aligned with predictions from the standard model.

It also boasts reduced uncertainty from the researchers’ previous analysis of the data, which they reported in 2018, increasing their confidence that they got the mass right.

But the updated mass is at odds with that of another group. In 2022, scientists from the Collider Detector at Fermilab, or CDF, experiment shocked the physics community with a measurement of 80,434 MeV — about 100 MeV heavier than expected (SN: 4/7/22). If the CDF report is correct, it implies that something is off with the standard model that has persevered in the face of every experimental challenge thrown at it over the last 50 years.

The W boson is responsible for the weak force, one of three fundamental forces in the standard model (SN: 2/5/83). And “it’s the only mass of a particle in the standard model that can be calculated,” says theoretical physicist Sven Heinemeyer of the Karlsruhe Institute of Technology in Germany. That is, the standard model theory yields a specific mass for the W boson, whereas the masses of other particles such as electrons and quarks are inputs and can be — as far as the theory is concerned — any value. Finding a W boson mass that’s different from standard model predictions would show the current theory is wrong.

The ATLAS reanalysis offers a stronger counterpoint to the CDF claim than the earlier ATLAS analysis of the same data. “The new analysis is an important confirmation of our previous result,” says Andreas Hoecker, a physicist at CERN.

The latest ATLAS value widens the chasm that separates CDF’s mass measurement from the herd of other studies. But it shouldn’t be seen as erasing CDF’s standard model challenge, says Duke University physicist Ashutosh Kotwal, a member of the CDF collaboration.

“The perspective on the CDF [announcement of a heavy W boson in 2022] does not change because of the ATLAS reanalysis,” Kotwal says. Because the reanalysis is based on data that ATLAS already released in 2017, he says, “the fact that ATLAS obtains a similar value as before is to be expected.”
Heinemeyer, who is not affiliated with ATLAS or CDF, sees a shift in the W boson mass landscape, but no sign of a resolution of the discrepancy.

“Having one new measurement is not enough,” Heinemeyer says. “If more and more measurements were to come out now from ATLAS and [other experiments], and they would all be in the same ballpark, at some point the community would decide CDF did something wrong.”

The next word on the W boson mass will probably come with pending studies from ATLAS and other experiments at CERN. The CDF experiment shut down in 2011, so it will not contribute further to the debate.

In the meantime, researchers hope to scrutinize each other’s analyses to search for clues that might help explain discrepancies in W boson mass measurements. “The CDF April 2022 paper provides a number of cross-checks of the CDF methodology and is transparent,” Kotwal says. “I look forward to detailed discussions of the ATLAS methodology.”

In the end, the conflict might reveal a new crack in the standard model. Or it could turn out to be another example of one of the most successful theories in history standing strong.

A 13-sided shape known as “the hat” has mathematicians tipping their caps.

It’s the first true example of an “einstein,” a single shape that forms a special tiling of a plane: Like bathroom floor tile, it can cover an entire surface with no gaps or overlaps but only with a pattern that never repeats.

“Everybody is astonished and is delighted, both,” says mathematician Marjorie Senechal of Smith College in Northampton, Mass., who was not involved with the discovery. Mathematicians had been searching for such a shape for half a century. “It wasn’t even clear that such a thing could exist,” Senechal says.

Although the name “einstein” conjures up the iconic physicist, it comes from the German ein Stein, meaning “one stone,” referring to the single tile. The einstein sits in a weird purgatory between order and disorder. Though the tiles fit neatly together and can cover an infinite plane, they are aperiodic, meaning they can’t form a pattern that repeats.

With a periodic pattern, it’s possible to shift the tiles over and have them match up perfectly with their previous arrangement. An infinite checkerboard, for example, looks just the same if you slide the rows over by two. While it’s possible to arrange other single tiles in patterns that are not periodic, the hat is special because there’s no way it can create a periodic pattern.
Identified by David Smith, a nonprofessional mathematician who describes himself as an “imaginative tinkerer of shapes,” and reported in a paper posted online March 20 at arXiv.org, the hat is a polykite — a bunch of smaller kite shapes stuck together. That’s a type of shape that hadn’t been studied closely in the search for einsteins, says Chaim Goodman-Strauss of the National Museum of Mathematics in New York City, one of a group of trained mathematicians and computer scientists Smith teamed up with to study the hat.

It’s a surprisingly simple polygon. Before this work, if you’d asked what an einstein would look like, Goodman-Strauss says, “I would’ve drawn some crazy, squiggly, nasty thing.”

Mathematicians previously knew of nonrepeating tilings that involved multiple tiles of different shapes. In the 1970s, mathematician Roger Penrose discovered that just two different shapes formed a tiling that isn’t periodic (SN: 3/1/07). From there, “It was natural to wonder, could there be a single tile that does this?” says mathematician Casey Mann of the University of Washington Bothell, who was not involved with the research. That one has finally been found, “it’s huge.”
Other shapes have come close. Taylor-Socolar tiles are aperiodic, but they are a jumble of multiple disconnected pieces — not what most people think of as a single tile. “This is the first solution without asterisks,” says mathematician Michaël Rao of CNRS and École Normale Supérieure de Lyon in France.

Smith and colleagues proved that the tile was an einstein in two ways. One came from noticing that the hats arrange themselves into larger clusters, called metatiles. Those metatiles then arrange into even larger supertiles, and so on indefinitely, in a type of hierarchical structure that is common for tilings that aren’t periodic. This approach revealed that the hat tiling could fill an entire infinite plane, and that its pattern would not repeat.

The second proof relied on the fact that the hat is part of a continuum of shapes: By gradually changing the relative lengths of the sides of the hat, the mathematicians were able to form a family of tiles that can take on the same nonrepeating pattern. By considering the relative sizes and shapes of the tiles at the extremes of that family — one shaped like a chevron and the other reminiscent of a comet — the team was able to show that the hat couldn’t be arranged in a periodic pattern.
While the paper has yet to be peer-reviewed, the experts interviewed for this article agree that the result seems likely to hold up to detailed scrutiny.

Nonrepeating patterns can have real-world connections. Materials scientist Dan Shechtman won the 2011 Nobel Prize in chemistry for his discovery of quasicrystals, materials with atoms arranged in an orderly structure that never repeats, often described as analogs to Penrose’s tilings (SN: 10/5/11). The new aperiodic tile could spark further investigations in materials science, Senechal says.

Similar tilings have inspired artists, and the hat appears to be no exception. Already the tiling has been rendered artistically as smiling turtles and a jumble of shirts and hats. Presumably it’s only a matter of time before someone puts hat tiles on a hat.

The new aperiodic monotile discovered by Dave Smith, Joseph Myers, Craig Kaplan, and Chaim Goodman-Strauss, rendered as shirts and hats. The hat tiles are mirrored relative to the shirt tiles. pic.twitter.com/BwuLUPVT5a

— Robert Fathauer (@RobFathauerArt) March 21, 2023
And the hat isn’t the end. Researchers should continue the hunt for additional einsteins, says computer scientist Craig Kaplan of the University of Waterloo in Canada, a coauthor of the study. “Now that we’ve unlocked the door, hopefully other new shapes will come along.”

The ghost catfish transforms from glassy to glam when white light passes through its mostly transparent body. Now, scientists know why.

The fish’s iridescence comes from light bending as it travels through microscopic striped structures in the animal’s muscles, researchers report March 13 in the Proceedings of the National Academy of Sciences.

Many fishes with iridescent flair have tiny crystals in their skin or scales that reflect light (SN: 4/6/21). But the ghost catfish (Kryptopterus vitreolus) and other transparent aquatic species, like eel larvae and icefishes, lack such structures to explain their luster.

The ghost catfish’s see-through body caught the eye of physicist Qibin Zhao when he was in an aquarium store. The roughly 5-centimeter-long freshwater fish is a popular ornamental species. “I was standing in front of the tank and staring at the fish,” says Zhao, of Shanghai Jiao Tong University. “And then I saw the iridescence.”

To investigate the fish’s colorful properties, Zhao and colleagues first examined the fish under different lighting conditions. The researchers determined its iridescence arose from light passing through the fish rather than reflecting off it. By using a white light laser to illuminate the animal’s muscles and skin separately, the team found that the muscles generated the multicolored sheen.
The researchers then characterized the muscles’ properties by analyzing how X-rays scatter when traveling through the tissue and by looking at it with an electron microscope. The team identified sarcomeres — regularly spaced, banded structures, each roughly 2 micrometers long, that run along the length of muscle fibers — as the source of the iridescence.

The sarcomeres’ repeating bands, comprised of proteins that overlap by varying amounts, bend white light in a way that separates and enhances its different wavelengths. The collective diffraction of light produces an array of colors. When the fish contracts and relaxes its muscles to swim, the sarcomeres slightly change in length, causing a shifting rainbow effect.
The purpose of the ghost catfish’s iridescence is a little unclear, says Heok Hee Ng, an independent ichthyologist in Singapore who was not involved in the new study. Ghost catfish live in murky water and seldom rely on sight, he says. But the iridescence might help them visually coordinate movements when traveling in schools, or it could help them blend in with shimmering water to hide from land predators, like some birds, he adds.

Regardless of function, Ng is excited to see scientists exploring the ghost catfish’s unusual characteristics.

“Fishes actually have quite a number of these interesting structures that serve them in many ways,” he says. “And a lot of these structures are very poorly studied.”

DNA from a 9,000-year-old baby tooth from Alaska, the oldest natural mummy in North America and remains of ancient Brazilians is helping researchers trace the steps of ancient people as they settled the Americas. Two new studies give a more detailed and complicated picture of the peopling of the Americas than ever before presented.

People from North America moved into South America in at least three migration waves, researchers report online November 8 in Cell. The first migrants, who reached South America by at least 11,000 years ago, were genetically related to a 12,600-year-old toddler from Montana known as Anzick-1 (SN: 3/22/14, p. 6). The child’s skeleton was found with artifacts from the Clovis people, who researchers used to think were the first people in the Americas, although that idea has fallen out of favor. Scientists also previously thought these were the only ancient migrants to South America.
But DNA analysis of samples from 49 ancient people suggests a second wave of settlers replaced the Clovis group in South America about 9,000 years ago. And a third group related to ancient people from California’s Channel Islands spread over the Central Andes about 4,200 years ago, geneticist Nathan Nakatsuka of Harvard University and colleagues found.
People who settled the Americas were also much more genetically diverse than previously thought. At least one group of ancient Brazilians shared DNA with modern indigenous Australians, a different group of researchers reports online November 8 in Science.
Early Americans moved into prehistoric South America in at least three migratory waves, a study proposes. Ancestral people who crossed from Siberia into Alaska first gave rise to groups that settled North America (gray arrows). The first wave of North Americans (blue) were related to Clovis people, represented by a 12,600-year-old toddler from Montana called Anzick-1. They moved into South America at least 11,000 years ago, followed by a second wave (green) whose descendants contributed most of the indigenous ancestry among South Americans today. A third migration wave (yellow) from a group that lived near California’s Channel Island moved into the Central Andes about 4,200 years ago. Dotted areas indicate that people there today still have that genetic ancestry.
Genetically related, but distinct groups of people came into the Americas and spread quickly and unevenly across the continents, says Eske Willerslev, a geneticist at the Natural History Museum of Denmark in Copenhagen and a coauthor of the Science study. “People were spreading like a fire across the landscape and very quickly adapted to the different environments they were encountering.”

Both studies offer details that help fill out an oversimplified narrative of the prehistoric Americas, says Jennifer Raff, an anthropological geneticist at the University of Kansas in Lawrence who was not involved in the work. “We’re learning some interesting, surprising things,” she says.

For instance, Willerslev’s group did detailed DNA analysis of 15 ancient Americans different from those analyzed by Nakatsuka and colleagues. A tooth from Trail Creek in Alaska was from a baby related to a group called the ancient Beringians, who occupied the temporary land mass between Alaska and Siberia called Beringia. Sometimes called the Bering land bridge, the land mass was above water before the glaciers receded at the end of the last ice age. The ancient Beringians stayed on the land bridge and were genetically distinct from the people who later gave rise to Native Americans, Willerslev and colleagues found.

The link between Australia and ancient Amazonians also hints that several genetically distinct groups may have come across Beringia into the Americas.

The Australian signature was first found in modern-day indigenous South Americans by Pontus Skoglund and colleagues (SN: 8/22/15, p. 6). No one was sure why indigenous Australians and South Americans shared DNA since the groups didn’t have any recent contact. One possibility, says Skoglund, a geneticist at the Francis Crick Institute in London and a coauthor of the Cell paper, was that the signature was very old and inherited from long-lost ancestors of both groups.

So Skoglund, Nakatsuka and colleagues tested DNA from a group of ancient Brazilians, but didn’t find the signature. Willerslev’s group, however, examined DNA from 10,400-year-old remains from Lagoa Santa, Brazil, and found the signature, supporting the idea that modern people could have inherited it from much older groups. And Skoglund is thrilled. “It’s amazing to see it confirmed,” he says.

How that genetic signature got to Brazil in the first place is still a mystery, though. Researchers don’t think early Australians paddled across the Pacific Ocean to South America. “None of us really think there was some sort of Pacific migration going on here,” Skoglund says.

That leaves an overland route through Beringia. There’s only one problem: Researchers didn’t find the Australian signature in any of the ancient remains tested from North or Central America. And no modern-day indigenous North or Central Americans tested have the signature either.

Still, Raff thinks it likely that an ancestral group of people from Asia split off into two groups, with one heading to Australia and the other crossing the land bridge into the Americas. The group that entered the Americas didn’t leave living descendants in the north. Or, because not many ancient remains have been studied, it’s possible that scientists have just missed finding evidence of this particular migration.

If Raff is right, that could mean that multiple groups of genetically distinct people made the Berigian crossing, or that one group crossed but was far more genetically diverse than researchers have realized.

The studies may also finally help lay to rest a persistent idea that some ancient remains in the Americas are not related to Native Americans today.

The Lagoa Santans from Brazil and a 10,700-year-old mummy from a place called Spirit Cave in Nevada had been grouped as “Paleoamericans” because they both had narrow skulls with low faces and protruding jaw lines, different from other Native American skull shapes. Some researchers have suggested that Paleoamericans — including the so-called Kennewick Man, whose 8,500-year-old remains were found in the state of Washington (SN: 12/26/15, p. 30) — weren’t Native Americans, but a separate group that didn’t have modern descendants.

But previous studies of Paleoamericans and Willerslev’s analysis of the Spirit Cave mummy’s DNA provide evidence that, despite their skull shapes, the Paleoamericans were not different from other Native Americans of their time. And the ancient people are more closely related to present-day Native Americans than any other group.

Willerslev presented the results about the Spirit Cave mummy to the Fallon Paiute-Shoshone tribe when the data became available. Based on the genetic results, the tribe was able to claim the mummy as an ancestor and rebury the remains.

What do you get when you flip a fossilized “jellyfish” upside down? The answer, it turns out, might be an anemone.

Fossil blobs once thought to be ancient jellyfish were actually a type of burrowing sea anemone, scientists propose March 8 in Papers in Palaeontology.

From a certain angle, the fossils’ features include what appears to be a smooth bell shape, perhaps with tentacles hanging beneath — like a jellyfish. And for more than 50 years, that’s what many scientists thought the animals were.
But for paleontologist Roy Plotnick, something about the fossils’ supposed identity seemed fishy. “It’s always kind of bothered me,” says Plotnick, of the University of Illinois Chicago. Previous scientists had interpreted one fossil feature as a curtain that hung around the jellies’ tentacles. But that didn’t make much sense, Plotnick says. “No jellyfish has that,” he says. “How would it swim?”

One day, looking over specimens at the Field Museum in Chicago, something in Plotnick’s mind clicked. What if the bell belonged on the bottom, not the top? He turned to a colleague and said, “I think this is an anemone.”

Rotated 180 degrees, Plotnick realized, the fossils’ shape — which looks kind of like an elongated pineapple with a stumpy crown — resembles some modern anemones. “It was one of those aha moments,” he says. The “jellyfish” bell might be the anemone’s lower body. And the purported tentacles? Perhaps the anemone’s upper section, a tough, textured barrel protruding from the seafloor.

Plotnick and his colleagues examined thousands of the fossilized animals, dubbed Essexella asherae, unearthing more clues. Bands running through the fossils match the shape of some modern anemones’ musculature. And some specimens’ pointy protrusions resemble an anemone’s contracted tentacles.
“It’s totally possible that these are anemones,” says Estefanía Rodríguez, an anemone expert at the American Museum of Natural History in New York City who was not involved with the work. The shape of the fossils, the comparison with modern-day anemones — it all lines up, she says, though it’s not easy to know for sure.

Paleontologist Thomas Clements agrees. Specimens like Essexella “are some of the most notoriously difficult fossils to identify,” he says. “Jellyfish and anemones are like bags of water. There’s hardly any tissue to them,” meaning there’s little left to fossilize.
Still, it’s plausible that the blobs are indeed fossilized anemones, says Clements, of Friedrich-Alexander-Universität Erlangen-Nürnberg in Germany. He was not part of the new study but has spent several field seasons at Mazon Creek, the Illinois site where Essexella lived some 310 million years ago. Back then, the area was near the shoreline, Clements says, with nearby rivers dumping sediment into the environment – just the kind of place ancient burrowing anemones may have once called home.

Disinfection of public drinking water is one of the great public health success stories of the 20th century. In 1900, outbreaks of cholera and typhoid, both caused by waterborne bacteria, were common in American cities. In 1908, Jersey City, N.J., became the first U.S. city to routinely disinfect community water. Other cities and towns quickly followed, and by 1920, the typhoid rate in the United States had dropped by 66 percent.

But that battle isn’t over. Around the world, more than 2 billion people lack reliable access to safe water (SN: 8/18/18, p. 14), and half a million people die each year from diarrhea caused by contaminated water, according to the World Health Organization.
And in the United States, challenges remain. The management failures that caused the 2014 lead contamination crisis in Flint, Mich., were a wake-up call (SN: 3/19/16, p. 8), but Flint is hardly alone. Systems in other big cities are also falling short. In October, officials in Newark, N.J., scrambled to hand out home water filters after it became clear that efforts to prevent lead from leaching into drinking water were not getting the job done. In the first six months of 2017, more than 22 percent of water samples in that city exceeded federal limits for lead, according to news reports.

If big cities are struggling, small towns with skimpy budgets as well as the many people who get their water from private wells often have it harder, lacking access to the infrastructure or technology to make water reliably safe. But science can help.

In this issue, Science News staff writer Laurel Hamers digs into the latest research on water treatment technology and finds a focus on efforts to invent affordable, scalable solutions. There’s a lot of engineering and chemistry involved, not surprisingly, and also physics — it’s hard to move water efficiently through a filter while also catching the bad stuff. Her story is a testament to researcher ingenuity, and a helpful primer on how a typical municipal water treatment plant works.

As I read Hamers’ story, I realized that I didn’t know how our water is treated here in Washington, D.C., even though I live barely a mile from one of the city’s two treatment plants. (I at least get credit for knowing the water comes from the Potomac River.) So I Googled it and found a description of how that process works. Plus I found data on potential contaminants such as Giardia and Cryptosporidium, as well as information on how residents can get their water tested for lead, which can leach from pipes or fixtures.
I also learned that each spring, the Washington Aqueduct briefly switches disinfectants from chloramine to chlorine while the agency cleans the water pipes. That might explain the short-lived swimming pool smell in the tap water.

For me, this became a double win; I learned a lot about advances in water treatment technology from Hamers’ reporting, and I was motivated to seek out information about my local water supply.

If other readers feel inspired by our work to learn more, count me as a happy journalist.

Devices that eavesdrop on neural activity can help paralyzed people command computer tablets to stream music, text friends, check the weather or surf the internet.

Three people with paralysis below the neck were able to navigate off-the-shelf computer tablets using an electrode array system called BrainGate2. The results, published November 21 in PLOS One, are the latest to show that neural signals can be harnessed to directly allow movement (SN: 6/16/12, p. 5).

The two men and one woman had electrode grids implanted over part of the motor cortex, an area of the brain that helps control movement. The brain implants picked up neural activity indicating that the participants were thinking about moving a cursor. Those patterns were then sent to a virtual mouse that was wirelessly paired to the tablet.
Using nothing more than their intentions to move a cursor, the three participants performed seven common digital tasks, including web browsing and sending e-mail. One participant looked up orchid care, ordered groceries online and played a digital piano. “The tablet became second nature to me, very intuitive,” she told the researchers when asked about her experience, according to the study.

Another participant enjoyed texting friends, “especially because I could interject some humor,” he told the scientists. The system even allowed two of the participants to chat with each other in real time.

For the study, the researchers used tablets with standard settings, without installing any shortcuts or features to make typing or navigation easier.

SAN DIEGO — Getting goose bumps doesn’t just make hairs stand on end; it may also help hair grow.

Nerves and muscles that raise goose bumps also stimulate stem cells in the skin to make hair follicles and grow hair. Ya-Chieh Hsu, a stem cell researcher at Harvard University, reported the unpublished findings December 9 at the joint meeting of the American Society for Cell Biology and the European Molecular Biology Organization. Getting goose bumps when it’s cold may encourage animals’ fur to grow thicker, Hsu said.
Nerves that are part of the sympathetic nervous system — which controls pupil dilation, heart rate and other automatic processes — nestle next to stem cells that will create hair follicles, Hsu and her colleagues found. Usually nerves are wrapped in a protective coating called myelin, like electrical wire sheathed in plastic. But Hsu’s group found that the nerves’ ends were naked where they meet hair follicle stem cells, like wires stripped at the tips to make contacts with electrical nodes.

The nerves secrete the hormone norepinephrine. That hormone is necessary for hair growth, the researchers found. Those findings might help explain why hair loss is a side effect of drugs known as beta-blockers, which interfere with norepinephrine’s action.

Sympathetic nerves next to hair follicles are also wrapped around tiny arrector pili muscles, which contract to make hair cells stand on end, causing goose bumps. Mice with mutations that prevented the muscles from growing also lacked the sympathetic nerves and didn’t grow hair normally. Men with male pattern baldness also lack arrector pili muscles in their scalps, Hsu said, suggesting that sympathetic nerves and goose bump–raising muscles may also be important in that type of baldness. Restoring the nerves and muscles may lead to new hair growth, she said.

An orbital oopsie has led to new proof of Albert Einstein’s physics prowess.

In 2014, two satellites intended for Europe’s Galileo network, the equivalent of the United States’ GPS network, were placed into orbit incorrectly, causing them to travel around Earth in ellipses rather than circles. That wasn’t ideal for the satellites’ originally intended navigational use, but scientists realized the wayward satellites were perfect for another purpose: testing Einstein’s theory of gravity, the general theory of relativity.

According to general relativity, gravity affects not just space, but also time. The deeper within a gravitational field you are, the slower time passes (SN: 10/17/15, p. 16). So a clock at a higher altitude will tick faster than one closer to Earth’s surface, where Earth’s gravity is stronger. The satellites’ orbital mishap allowed the most precise test yet of this effect, known as gravitational redshift, two teams of scientists report in a pair of papers in the Dec. 7 Physical Review Letters.

As the two misplaced satellites move in their elliptical orbits, their distance from Earth periodically increases and decreases by about 8,500 kilometers. Using the precise atomic clocks on the satellites, the scientists studied how that altitude change affected the flow of time. The clocks sped up and slowed down by tiny fractions of a second as expected, agreeing with the predictions of general relativity within a few thousandths of a percent, the teams report.