Small stone points such as this one, unearthed at a French rock-shelter, served as arrowheads for Homo sapiens who introduced archery to Europe around 54,000 years ago, researchers say.
Homo sapiens who reached Europe around 54,000 years ago introduced bows and arrows to that continent, a new study suggests.
Researchers examined tiny triangular stone points and other artifacts excavated at a rock-shelter in southern France called Grotte Mandrin. H. sapiens on the move probably brought archery techniques from Africa to Europe , archaeologist Laure Metz of Aix-Marseille University in France and colleagues report February 22 in Science Advances .
“Metz and colleagues demonstrate bow hunting [at Grotte Mandrin] as convincingly as possible without being caught bow-in-hand,” says archaeologist Marlize Lombard of the University of Johannesburg, who did not participate in the new study.
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No bows were found at the site. Wooden items such as bows preserve poorly. The oldest intact bows, found in northern European bogs, date to around 11,000 years ago, Metz says.
“We’ve shown that the earliest known Homo sapiens to migrate into Neandertal territories had mastered the use of the bow,” Metz says.
No evidence suggests that Neandertals already present in Europe at that time launched arrows at prey. It’s also unclear whether archery provided any substantial hunting advantages to H. sapiens relative to spears that were thrust or thrown by Neandertals.
Among 852 stone artifacts excavated in a H. sapiens sediment layer at Grotte Mandrin dated to about 54,000 years ago, 196 triangular stone points displayed high-impact damage. Another 15 stone points showed signs of both high-impact damage and alterations caused by butchery activities, such as cutting.
Comparisons of those finds were made to damage on stone replicas of the artifacts that the researchers used as arrowheads shot from bows and as the tips of spears inserted in handheld throwing devices. Additional comparative evidence came from stone and bone arrowheads used by recent and present-day hunting groups.
Impact damage along the edges of stone points from the French site indicated that these implements had been attached at the bottom to shafts.
The smallest Grotte Mandrin points, many with a maximum width of no more than 10 millimeters, could have pierced animals’ hides only when shot from bows as the business ends of arrows, the researchers say. Experiments they conducted with replicas of the ancient stone points found that stone points less than 10 millimeters wide reach effective hunting speeds only when attached to arrow shafts propelled by a bow.
Larger stone points, some of them several times the size of the smaller points, could have been arrowheads or might have tipped spears that were thrown or thrust by hand or launched from handheld spear throwers, the researchers conclude.
Lombard, the University of Johannesburg archaeologist, suspects that the first H. sapiens at the French rock-shelter hunted with bows and arrows as well as with spears, depending on where and what they were hunting. Earlier studies directed by Lombard indicated that sub-Saharan Africans similarly alternated between these two types of hunting weapons starting between about 70,000 and 58,000 years ago.
H. sapiens newcomers to Europe may have learned from Neandertals that spear hunting in large groups takes precedence on frigid landscapes, where bow strings can easily snap and long-distance pursuit of prey is not energy efficient, Lombard says.
But learning about archery from H. sapiens may not have been in the cards for Neandertals. Based on prior analyses of brain impressions on the inside surfaces of fossil skulls, Lombard suspects that Neandertals’ brains did not enable the enhanced visual and spatial abilities that H. sapiens exploited to hunt with bows and arrows.
That’s a possibility, though other controversial evidence suggests that Neandertals behaved no differently from Stone Age H. sapiens ( SN: 3/26/20 ).If Grotte Mandrin Neandertals never hunted with bows and arrows but still survived just fine alongside H. sapiens archers for roughly 14,000 years, reasons for Neandertals’ ultimate demise remain as mysterious as ever.
Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.
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Electrons each behave like a tiny version of a bar magnet (shown), with their own magnetic field. A new measurement characterizes the electron’s magnetism more precisely than ever before.
No one has ever probed a particle more stringently than this.
In a new experiment, scientists measured a magnetic property of the electron more carefully than ever before, making the most precise measurement of any property of an elementary particle, ever. Known as the electron magnetic moment, it’s a measure of the strength of the magnetic field carried by the particle.
That property is predicted by the standard model of particle physics, the theory that describes particles and forces on a subatomic level. In fact, it’s the most precise prediction made by that theory.
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By comparing the new ultraprecise measurement and the prediction, scientists gave the theory one of its strictest tests yet. The new measurement agrees with the standard model’s prediction to about 1 part in a trillion, or 0.1 billionths of a percent, physicists report in the February 17 Physical Review Letters .
When a theory makes a prediction at high precision, it’s like a physicist’s Bat Signal, calling out for researchers to test it. “It’s irresistible to some of us,” says physicist Gerald Gabrielse of Northwestern University in Evanston, Ill.
To measure the magnetic moment, Gabrielse and colleagues studied a single electron for months on end, trapping it in a magnetic field and observing how it responded when tweaked with microwaves. The team determined the electron magnetic moment to 0.13 parts per trillion, or 0.000000000013 percent.
A measurement that exacting is a complicated task. “It’s so challenging that nobody except the Gabrielse team dares to do it,” says physicist Holger Müller of the University of California, Berkeley.
The new result is more than twice as precise as the previous measurement, which stood for over 14 years, and which was also made by Gabrielse’s team. Now the researchers have finally outdone themselves. “When I saw the [paper] I said, ‘Wow, they did it,’” says Stefano Laporta, a theoretical physicist affiliated with University of Padua in Italy, who works on calculating the electron magnetic moment according to the standard model.
The new test of the standard model would be even more impressive if it weren’t for a conundrum in another painstaking measurement. Two recent experiments, one led by physicist Saïda Guellati-Khélifa of Kastler Brossel Laboratory in Paris and the other by Müller, disagree on the value of a number called the fine-structure constant , which characterizes the strength of electromagnetic interactions ( SN: 4/12/18 ). That number is an input to the standard model’s prediction of the electron magnetic moment. So the disagreement limits the new test’s precision. If that discrepancy were sorted out, the test would become 10 times as precise as it is now.
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The stalwart standard model has stood up to a barrage of experimental tests for decades. But scientists don’t think it’s the be-all and end-all. That’s in part because it doesn’t explain observations such as the existence of dark matter, an invisible substance that exerts gravitational influence on the cosmos. And it doesn’t say why the universe contains more matter than antimatter ( SN: 9/22/22 ). So physicists keep looking for cases where the standard model breaks down.
One of the most tantalizing hints of a failure of the standard model is the magnetic moment not of the electron, but of the muon, a heavy relative of the electron. In 2021, a measurement of this property hinted at a possible mismatch with standard model predictions ( SN: 4/7/21 ).
“Some people believe that this discrepancy could be the signature of new physics beyond the standard model,” says Guellati-Khélifa, who wrote a commentary on the new electron magnetic moment paper in Physics magazine. If so, any new physics affecting the muon could also affect the electron. So future measurements of the electron magnetic moment might also deviate from the prediction, finally revealing the standard model’s flaws.
Physics writer Emily Conover has a Ph.D. in physics from the University of Chicago. She is a two-time winner of the D.C. Science Writers’ Association Newsbrief award.
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The Milky Way spawns stars in places such as the Rosette Nebula, seen here in a far-infrared image from the Herschel Space Telescope, and does so with much more vigor than astronomers had thought, according to a new study.
The Milky Way is churning out far more stars than previously thought, according to a new estimate of its star formation rate.
Gamma rays from aluminum-26, a radioactive isotope that arises primarily from massive stars, reveal that the Milky Way converts four to eight solar masses of interstellar gas and dust into new stars each year , researchers report in work submitted to arXiv.org on January 24. That range is two to four times the conventional estimate and corresponds to an annual birthrate in our galaxy of about 10 to 20 stars, because most stars are less massive than the sun.
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At this rate, every million years — a blink of the eye in astronomical terms — our galaxy spawns 10 million to 20 million new stars. That’s enough to fill roughly 10,000 star clusters like the beautiful Pleiades cluster in the constellation Taurus. In contrast, many galaxies, including most of the ones that orbit the Milky Way, make no new stars at all.
“The star formation rate is very important to understand for galaxy evolution,” says Thomas Siegert, an astrophysicist at the University of Würzburg in Germany. The more stars a galaxy makes, the faster it enriches itself with oxygen, iron and the other elements that stars create. Those elements then alter star-making gas clouds and can change the relative number of large and small stars that the gas clouds form.
Siegert and his colleagues studied the observed intensity and spatial distribution of emission from aluminum-26 in our galaxy. A massive star creates this isotope during both life and death. During its life, the star blows the aluminum into space via a strong wind. If the star explodes when it dies, the resulting supernova forges more. The isotope, with a half-life of 700,000 years, decays and gives off gamma rays.
Like X-rays, and unlike visible light, gamma rays penetrate the dust that cloaks the youngest stars. “We’re looking through the entire galaxy,” Siegert says. “We’re not X-raying it; here we’re gamma-raying it.”
The revised rate is very realistic, says Pavel Kroupa, an astronomer at the University of Bonn in Germany who was not involved in the work. “I’m very impressed by the detailed modeling of how they account for the star formation process,” he says. “It’s a very beautiful work. I can see some ways of improving it, but this is really a major step in the absolutely correct direction.”
Siegert cautions that it is difficult to tell how far the gamma rays have traveled before reaching us. In particular, if some of the observed emission arises nearby — within just a few hundred light-years of us — then the galaxy has less aluminum-26 than the researchers have calculated, which means the star formation rate is on the lower side of the new estimate. Still, he says it’s unlikely to be as low as the standard two solar masses per year.
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In any event, the Milky Way is the most vigorous star creator in a collection of more than 100 nearby galaxies called the Local Group. The largest Local Group galaxy, Andromeda, converts only a fraction of a solar mass of gas and dust into new stars a year. Among Local Group galaxies, the Milky Way ranks second in size, but its high star formation rate means that we definitely try a lot harder.
Ken Croswell has a Ph.D. in astronomy from Harvard University and is the author of eight books, including The Alchemy of the Heavens: Searching for Meaning in the Milky Way and The Lives of Stars.
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For the first time, researchers have harnessed the body’s own chemistry to “grow” electrodes inside the tissues of living fish, blurring the boundary between biology and machines.
The technique uses the body’s sugars to turn an injected gel into a flexible electrode without damaging tissues, experiments show. Zebrafish with these electrodes grown in their brains, hearts and tail fins showed no signs of ill effects, and ones tested in leeches successfully stimulated a nerve, researchers report in the Feb. 24 Science .
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Someday, these electrodes could be useful for applications ranging from studying how biological systems work to improving human-machine interfaces. They also could be used in “bioelectronic medicine,” such as brain stimulation therapies for depression , Parkinson’s disease and other conditions ( SN: 2/10/19 ).
Soft electronics aim to bridge the gap between soft, curvy biology and electronic hardware. But these electronics typically still must carry certain parts that can be prone to cracks and other issues, and inserting these devices inevitably causes damage to tissues.
“All the devices we have made, even though we have made them flexible, to make them more soft, when we introduce them, there will still be a scar. It’s like sticking a knife into the organ,” says Magnus Berggren, a materials scientist at Linköping University in Sweden. That scarring and inflammation can degrade electrode performance over time.
Previous efforts to grow soft electronics inside tissues have drawbacks. One approach uses electrical or chemical signals to power the transformation from chemical soup to conducting electrodes, but these zaps also cause damage. A 2020 study got around this problem by genetically modifying cells in worms to produce an engineered enzyme that does the job, but the new method achieves its results without genetic alterations.
Berggren and colleagues’ electrodes instead exploit a natural energy source already present in the body: sugars. The gel cocktail contains molecules called oxidases that react with the sugars — glucose or lactate — to produce hydrogen peroxide. That then activates another ingredient in the cocktail, an enzyme called hydrogen peroxidase, which is the catalyst needed to transform the gel into a conducting electrode.
“The approach leverages elegant chemistry to overcome many of the technical challenges,” says biomedical engineer Christopher Bettinger of Carnegie Mellon University in Pittsburgh, who was not involved in the study.
To test the technique, the researchers injected the cocktail into the brains, hearts and tail fins of transparent zebrafish. The gel turns blue when it becomes conductive, giving a visual readout of its success.
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“The beautiful thing is you can see it: The zebrafishes’ tail changes color, and we know that blue indicates a conducting polymer,” says materials scientist Xenofon Strakosas, also of Linköping University. “The first time I saw it, I thought ‘Wow, it’s really working!’”
The fish appeared to suffer no ill effects, and the researchers saw no evidence of tissue damage. In partially dissected leeches, the team showed that delivering a current to a nerve via a soft electrode could induce muscle contractions. Ultimately, devices like this could be paired with various wireless technologies in development.
Long-term implant performance remains to be determined, however. “The demonstrations are impressive,” Bettinger says. “What remains to be seen is the stability of the electrode.” Over time, substances in the body could react with the electrode materials, degrading it or even producing toxic substances.
The team still needs to refine how precisely the electrodes can stimulate nerves, says chemical engineer Zhenan Bao of Stanford University, who was not involved in the work. She and colleagues developed the way to “grow” electrical components using genetic modifications. Ensuring stimulation is concentrated where it’s needed for a treatment, while preventing the leakage of current to unwanted regions will be important, she says.
In the new study, the relative abundance of different sugars in different tissues determines exactly where electrodes form. But in the future, a component of the main ingredient could be swapped out for elements that attach to specific bits of biology to make targeting much more precise, Berggren says. “We’re conducting experiments right now where we’re trying to bind these materials directly on individual cells.” Notes Strakosas: “There are some applications where precision is really important; that’s where we have to invest effort.”
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Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
Should aliens ever encounter NASA’s Voyager spacecraft, they’ll find the Golden Record (left, cover shown right), which is packed with sounds and images of Earth.
The chances of contacting extraterrestrial civilizations seem poor – Science News , February 24, 1973
The possibility of life … on other planets has stimulated many people’s imaginations…. In the Feb. 9 Nature , James C. G. Walker of Yale University studies the possible parameters of such a search and comes to some pessimistic conclusions.
Walker estimated it could take 1,400 to 14 million years to contact E.T. with the available technology. That’s way longer than researchers have spent listening for alien radio signals and scouring the sky with telescopes and satellites ( SN: 11/21/20, p. 18 ).
Despite the silence, scientists have sent their own messages into the void. In 1974, Earth sent a string of binary code from the Arecibo Observatory in Puerto Rico. Years later, arguably the most famous message — the Golden Record — made its way to space aboard NASA spacecraft ( SN: 8/20/77, p. 124 ).
If aliens ever reach out, they may send quantum dispatches , scientists say ( SN: 8/13/22, p. 5 ). Even so, the aliens are likely so far from Earth that their civilization will have collapsed by the time we get the message ( SN: 4/14/18, p. 9 ).
A version of this article appears in the February 25, 2023 issue of Science News.
Erin I. Garcia de Jesus is a staff writer at Science News . She holds a Ph.D. in microbiology from the University of Washington and a master’s in science communication from the University of California, Santa Cruz.
Our mission is to provide accurate, engaging news of science to the public. That mission has never been more important than it is today.
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Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
A new biomaterial, pictured in a University of California, San Diego laboratory, can be injected through the veins to heal tissue after a heart attack.
A new biomaterial delivered to the heart soon after a heart attack can heal damaged tissue from the inside out.
Heart attacks kill cardiac muscle tissue, scarring the heart and leaving permanent damage after just six hours. The damage prevents the heart from functioning properly. If there was a way to begin healing damaged tissue soon after a heart attack, doctors could prevent scar tissue from developing.
“In an ideal world, you treat a patient immediately when they’re having a heart attack to try to salvage some of the tissue and promote regeneration,” says Karen Christman, a bioengineer at the University of California, San Diego.
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“I think it has a lot of potential,” Vimala Bharadwaj, a biomedical scientist at Stanford University who was not involved in the research. The paper “is definitely good proof of concept for what they’re trying to do.”
Previously, researchers found that stem cells derived from body fat can be used to heal bones, muscles and the heart ( SN: 3/9/16 ). Christman wanted to work with the extracellular matrix, the lattice of proteins that provide structural support to the cells in cardiac muscle tissue. Like stems cells, it has regenerative abilities but is much less expensive, she says.
In 2009, Christman’s team produced a hydrogel using particles from this matrix. Trials in rats and later in humans showed that the material bonded to damaged areas and promoted cell repair and growth. However, due to relatively large particles of the hydrogel, it could be delivered to the heart only via a needle.
“Poking the heart with a needle could set off an arrhythmia,” says Christman. To use this treatment, doctors would need to wait a few weeks until the heart is more stable and the chance of these irregular heartbeats decreases. And that would be too late to prevent scarring.
The team took the previously created hydrogel, sifted out the larger particles with a centrifuge so only nanoparticles remained, and added water to dilute the mixture. That created a material thin enough to deliver to heart blood vessels intravenously.
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Based on the nanoparticles’ size, the team expected the mixture would slip through any gaps in cardiac blood vessels caused by the heart attack and adhere to the surrounding tissue. Once there, it would create a protective barrier while the heart healed.
Instead, animal experiments showed that the extracellular matrix material bound to the leaky vessels, preventing some inflammatory cells from moving into the heart tissue in the first place and causing further damage. The material reduced inflammation in the heart and stimulated the healing process by encouraging cell growth, the team reports.
Further safety studies will be needed to get the biomaterial ready for clinical trials. The first trial in humans will most likely be for repairing cardiac tissue post–heart attack. “A lot of my motivation is moving things out of the lab, actually into the real world,” Christman says.
Another real-world application of the biomaterial could be treatment for leaky blood vessels in other hard-to-access organs, including in the brain after a traumatic injury, Christman notes.
While Bharadwaj finds that application potentially promising, she says tests are needed to see whether the biomaterial improves headaches and cognitive or memory deficits in the brain after a traumatic injury. That’s needed to gauge whether it really is an effective TBI treatment.
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Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
