Ray spiders deploy an unusual strategy to capture prey in their webs. They essentially pull it back into a cone shape and release it when prey approaches, trapping said prey in the sticky silken threads. A few years ago, scientists noticed that they could get the spiders to release their webs just by snapping their fingers nearby, suggesting that the spiders relied at least in part on sound vibrations to know when to strike. Evidence for that hypothesis has now been confirmed in a new paper published in the Journal of Experimental Biology.

Most spider orb webs are static: the spiders weave them and fix them in place and then wait for prey to fly into the webs. That causes the silk threads to vibrate, alerting the spider that dinner is served. There are some species that actively actuate their webs, however, per the authors.

For instance, the triangle weaver spring-loads its triangular web once an insect has made contact so that the threads wrap around the prey in fractions of a second. Bolas spiders seem to detect prey in their vicinity through auditory cues, throwing a line of silk with a sticky end at passing moths to catch them. Ogre-faced spiders also seem to be able to hear potential prey, striking backward with a small silk net held in their front legs. It's a more proactive hunting strategy than merely waiting for prey to fly into a web.

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On April 15, 2019, the world watched in transfixed horror as a fire ravaged the famed Cathedral of Notre Dame in Paris, collapsing the spire and melting the lead roof. After years of painstaking restoration costing around $740 million, the cathedral reopens to the public this weekend. The December issue of National Geographic features an exclusive look inside the restored cathedral, accompanied by striking photographs by Paris-based photographer and visual artist Tomas van Houtryve.

For several hours, it seemed as if the flames would utterly destroy the 800-year-old cathedral. But after a long night of work by more than 400 Paris firefighters, the fire finally began to cool and attention began to shift to what could be salvaged and rebuilt. French President Emmanuel Macron vowed to restore Notre Dame to its former glory and set a five-year deadline. The COVID-19 pandemic caused some delays, but France nearly met that deadline regardless.

Those reconstruction efforts were helped by the fact that, a few years before the fire, scientist Andrew Tallon had used laser scanning to create precisely detailed maps of the interior and exterior of the cathedral—an invaluable aid as Paris rebuilds this landmark structure. French acousticians had also made detailed measurements of Notre Dame's "soundscape" that were instrumental in helping architects factor acoustics into their reconstruction plans. The resulting model even enabled Brian FG Katz, research director of the National Center for Scientific Research (CNRS) at Sorbonne University, to create a virtual reality version of Notre Dame with all the acoustical parameters in place.

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There's a common popular science demonstration involving "soap boats," in which liquid soap poured onto the surface of water creates a propulsive flow driven by gradients in surface tension. But it doesn't last very long since the soapy surfactants rapidly saturate the water surface, eliminating that surface tension. Using ethanol to create similar "cocktail boats" can significantly extend the effect because the alcohol evaporates rather than saturating the water.

That simple classroom demonstration could also be used to propel tiny robotic devices across liquid surfaces to carry out various environmental or industrial tasks, according to a preprint posted to the physics arXiv. The authors also exploited the so-called "Cheerios effect" as a means of self-assembly to create clusters of tiny ethanol-powered robots.

As previously reported, those who love their Cheerios for breakfast are well acquainted with how those last few tasty little "O"s tend to clump together in the bowl: either drifting to the center or to the outer edges. The "Cheerios effect is found throughout nature, such as in grains of pollen (or, alternatively, mosquito eggs or beetles) floating on top of a pond; small coins floating in a bowl of water; or fire ants clumping together to form life-saving rafts during floods. A 2005 paper in the American Journal of Physics outlined the underlying physics, identifying the culprit as a combination of buoyancy, surface tension, and the so-called "meniscus effect."

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Paleontologists have long puzzled over how the dinosaurs—originally relatively small and of minor importance to the broader ecosystem—evolved to become the dominant species some 30 million years later. Fossilized feces and vomit from dinosaurs might hold important clues to how and why this evolutionary milestone came about, according to a new paper published in the journal Nature.

Co-author Martin Qvarnström, an evolutionary biologist with Uppsala University in Sweden, and his collaborators studied trace fossils known as bromalites, a designation that includes coprolites as well as vomit or other fossilized matter from an organism's digestive tract. As previously reported, coprolites aren't quite the same as paleofeces, which retain a lot of organic components that can be reconstituted and analyzed for chemical properties. Coprolites are fossils, so most organic components have been replaced by mineral deposits like silicate and calcium carbonates.

For archaeologists keen on learning more about the health and diet of past populations—as well as how certain parasites evolved in the evolutionary history of the microbiome—coprolites and paleofeces can be a veritable goldmine of information. For instance, in 2021 we reported on an analysis of preserved paleo-poop revealing that ancient Iron Age miners in what is now Austria were fond of beer and blue cheese.

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Virtual reality (VR) technology has long sought to incorporate the human senses into virtual and mixed-reality environments. In addition to sight and sound, researchers have been trying to add the sensation of human touch and smell via various user interfaces, as well as taste. But the latter has proved to be quite challenging. A team of Hong Kong scientists has now developed a handheld user interface shaped like a lollipop capable of re-creating several different flavors in a virtual environment, according to a new paper published in the Proceedings of the National Academy of Sciences (PNAS).

It's well established that human taste consists of sweet, salty, sour, bitter, and umami—five basic flavors induced by chemical stimulation of the tongue and, to a lesser extent, in parts of the pharynx, larynx, and epiglottis. Recreating those sensations in VR has resulted in a handful of attempts at a flavor user interface, relying on such mechanisms as chemical, thermal, and electrical stimulation, as well as iontophoresis.

The chemical approach usually involves applying flavoring chemicals directly onto the tongue, but this requires room for bulk storage of said chemicals, and there is a long delay time that is not ideal for VR applications. Thermal variations applied directly to the tongue can stimulate taste sensations but require a complicated system incorporating a cooling subsystem and temperature sensors, among other components.

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In the wee hours of December 26, 2004, a massive 9.2 earthquake occurred in the Indian Ocean, generating an equally massive tsunami that caused unprecedented devastation to 14 countries and killed more than 230,000 people. Twenty years later, National Geographic has revisited one of the deadliest natural disasters in recorded history with a new documentary: Tsunami: Race Against Time. The four-part series offers an in-depth account of the tsunami's destructive path, told from the perspectives of those who survived, as well as the scientists, journalists, doctors, nurses, and everyday heroes who worked to save as many as possible.

Geophysicist Barry Hirshorn—now with Scripps Institution of Oceanography at the University of California, San Diego—was on duty at the Pacific Tsunami Warning Center in Hawaii that day (3 pm on Christmas Day local time). His pager went off, indicating that seismic waves had set off a seismometer in Australia, and Hirshorn rushed to the control room to locate the quake's epicenter with his colleague, Stuart Weinstein.

They initially pegged the quake at 8.5 magnitude. (It was later upgraded to 8.9 and subsequently to a whopping 9.2 to 9.3 magnitude.) But despite its strength, they initially did not think the quake would generate a tsunami, at least in the Pacific. And such events were incredibly rare in the Indian Ocean.

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The duck-billed dinosaur Parasaurolophus is distinctive for its prominent crest, which some scientists have suggested served as a kind of resonating chamber to produce low-frequency sounds. Nobody really knows what Parasaurolophus sounded like, however. Hongjun Lin of New York University is trying to change that by constructing his own model of the dinosaur's crest and its acoustical characteristics. Lin has not yet reproduced the call of Parasaurolophus, but he talked about his progress thus far at a virtual meeting of the Acoustical Society of America.

Lin was inspired in part by the dinosaur sounds featured in the Jurassic Park film franchise, which were a combination of sounds from other animals like baby whales and crocodiles. “I’ve been fascinated by giant animals ever since I was a kid. I’d spend hours reading books, watching movies, and imagining what it would be like if dinosaurs were still around today,” he said during a press briefing. “It wasn’t until college that I realized the sounds we hear in movies and shows—while mesmerizing—are completely fabricated using sounds from modern animals. That’s when I decided to dive deeper and explore what dinosaurs might have actually sounded like.”

A skull and partial skeleton of Parasaurolophus were first discovered in 1920 along the Red Deer River in Alberta, Canada, and another partial skull was discovered the following year in New Mexico. There are now three known species of Parasaurolophus; the name means "near crested lizard." While no complete skeleton has yet been found, paleontologists have concluded that the adult dinosaur likely stood about 16 feet tall and weighed between 6,000 to 8,000 pounds. Parasaurolophus was an herbivore that could walk on all four legs while foraging for food but may have run on two legs.

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The US Capitol building in Washington, DC, is adorned with multiple lavish murals created in the 19th century by Italian artist Constantino Brumidi. These include panels in the Senate first-floor corridors, Room H-144, and the rotunda. The crowning glory is The Apotheosis of Washington on the dome of the rotunda, 180 feet above the floor.

Brumidi worked in various mediums, including frescoes. Among the issues facing conservators charged with maintaining the Capitol building frescoes is delamination. Artists apply dry pigments to wet plaster to create a fresco, and a good fresco can last for centuries. Over time, though, the decorative plaster layers can separate from the underlying masonry, introducing air gaps. Knowing precisely where such delaminated areas are, and their exact shape, is crucial to conservation efforts, yet the damage might not be obvious to the naked eye.

Acoustician Nicholas Gangemi is part of a research group led by Joseph Vignola at the Catholic University of America that has been using laser Doppler vibrometry to pinpoint delaminated areas of the Capitol building frescoes. It's a non-invasive method that zaps the frescoes with sound waves and measures the vibrational signatures that reflect back to learn about the structural conditions. This in turn enables conservators to make very precise repairs to preserve the frescoes for future generations.

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Archaeologists have discovered numerous ceramic or clay whistles at Aztec sites, dubbed "death whistles" because of their distinctive skull shapes. A new paper published in the journal Communications Psychology examines the acoustical elements of the unique shrieking sounds produced by those whistles, as well as how human listeners are emotionally affected by the sounds. The findings support the hypothesis that such whistles may have been used in Aztec religious rituals or perhaps as mythological symbols.

Archaeologists unearthed the first Aztec death whistles, also known as ehecachichtlis, in 1999 while excavating the Tlatelolco site in Mexico City. They found the body of a sacrificial victim, a 20-year-old male who had been beheaded, at the base of the main stairway of a temple dedicated to the wind god Ehecatl. The skeleton was clutching two ceramic skull-shaped whistles, one in each hand, along with other artifacts. More skull whistles were subsequently found, and they've found their way into popular culture. For instance, in Ghostbusters: Afterlife (2021), Egon Spengler had such a whistle in his secret laboratory collection.

Scholars have puzzled over the purpose of the skull whistles, although given the dearth of concrete evidence, most suggestions are highly speculative. One hypothesis is that it was used in battle, with hundreds of warriors blowing their whistles simultaneously as a battle cry. Music archaeologist Arnd Adje Both has dismissed that idea, suggesting instead that the whistle's purpose was more likely tied to ceremonial or religious practices, like human sacrifice. Yet another hypothesis proposes that the whistles were intended as symbols of a deity. The skull shape, for instance, might allude to the Aztec god of the underworld, Mictlantecuhtli.

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University of Rochester physicist Ranga Dias made headlines with his controversial claims of high-temperature superconductivity—and made headlines again when the two papers reporting the breakthroughs were later retracted under suspicion of scientific misconduct, although Dias denied any wrongdoing. The university conducted a formal investigation over the past year and has now terminated Dias' employment, The Wall Street Journal reported.

Ars has been following this story ever since Dias first burst onto the scene with reports of a high-pressure, room-temperature superconductor, published in Nature in 2020. Even as that paper was being retracted due to concerns about the validity of some of its data, Dias published a second paper in Nature claiming a similar breakthrough: a superconductor that works at high temperatures but somewhat lower pressures. Shortly afterward, that paper was retracted as well. As Ars Science Editor John Timmer reported previously:

Dias' lab was focused on high-pressure superconductivity. At extreme pressures, the orbitals where electrons hang out get distorted, which can alter the chemistry and electronic properties of materials. This can mean the formation of chemical compounds that don't exist at normal pressures, along with distinct conductivity. In a number of cases, these changes enabled superconductivity at unusually high temperatures, although still well below the freezing point of water.

Dias, however, supposedly found a combination of chemicals that would boost the transition to superconductivity to near room temperature, although only at extreme pressures. While the results were plausible, the details regarding how some of the data was processed to produce one of the paper's key graphs were lacking, and Dias didn't provide a clear explanation.

The ensuing investigation cleared Dias of misconduct for that first paper. Then came the second paper, which reported another high-temperature superconductor forming at less extreme pressures. However, potential problems soon became apparent, with many of the authors calling for its retraction, although Dias did not.

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Spooky season has come and gone, but those Halloween revelers who took in a haunted house during the season might just have boosted their immune systems by doing so, according to a new paper published in the journal Brain, Behavior, and Immunity.

As previously reported, fear is typically viewed as a negative emotion, an adverse reaction to keep us on our toes with regard to potential dangers in our environment. But human beings also tend to seek out scary movies, horror novels, or haunted houses—and not just during the Halloween season. This tendency has been dubbed "recreational fear" in the academic literature: a "mixed emotional experience of fear and enjoyment."

Co-author Mathias Clasen of Aarhus University, author of Why Horror Seduces, specializes in studying recreational fear and and co-directs the Recreational Fear Lab with cognitive scientist Marc Andersen. For instance, Clasen and his colleagues have examined the dominant personality traits of horror fans. (They tend to score high on openness to experience, also called intellect imagination.) In 2019 we reported on his investigation of two different fear-regulation strategies employed by subjects participating in a Danish haunted house: "adrenaline junkies," who lean into the fear, and "white-knucklers," who try to tamp down their fear.

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Last year we reported on preliminary research suggesting that ancient Egyptians may have used hallucinogens in their religious rituals, based on the presence of a few key chemical signatures taken from a ceremonial mug. Now those researchers have extended their analysis and fully identified the chemical components of those samples, confirming those preliminary findings, according to a new paper published in the journal Scientific Reports.

There is ample evidence that humans in many cultures throughout history used various hallucinogenic substances in religious ceremonies or shamanic rituals. That includes not just ancient Egypt but also ancient Greek, Vedic, Maya, Inca, and Aztec cultures. The Urarina people who live in the Peruvian Amazon Basin still use a psychoactive brew called ayahuasca in their rituals, and Westerners seeking their own brand of enlightenment have also been known to participate.

Last year, David Tanasi, of the University of South Florida, posted a preprint on his preliminary analysis of a ceremonial mug decorated with the head of Bes, a popular deity believed to confer protection on households, especially mothers and children. So unlike most other Egyptian deities, images of Bes were quite common in Egyptian homes. There were even special chambers built to honor Bes and his wife, Beset, at the Saqqara site near Cairo, which Egyptologists think could have been used for fertility or healing rituals, although their exact purpose is not certain (Bes was an ancient Egyptian deity of protection, fertility, healing, and purification). The mug is part of the collection of the Tampa Museum of Art.

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In 1971, Stanford University psychologist Philip Zimbardo conducted a notorious experiment in which he randomly divided college students into two groups, guards and prisoners, and set them loose in a simulated prison environment for six days, documenting the guards' descent into brutality. His findings caused a media sensation and a lot of subsequent criticism about the ethics and methodology employed in the study. Zimbardo died last month at 91, but his controversial legacy continues to resonate some 50 years later with The Stanford Prison Experiment: Unlocking the Truth, a new documentary from National Geographic.

Director Juliette Eisner started working on the documentary during the pandemic when, like most people, she had a lot of extra time on her hands. She started looking at old psychological studies exploring human nature and became fascinated by the Stanford Prison Experiment, especially in light of the summer protests in 2020 concerning police brutality. She soon realized that the prevailing narrative was Zimbardo's and that very few of the original subjects in the experiment had ever been interviewed about their experiences.

"I wanted to hear from those people," Eisner told Ars. "They were very hard to find. Most of them were still only known by alias or by prisoner number." Eisner persevered and tracked most of them down. "Every single time they picked up the phone, they were like, 'Oh, I'm so glad you called. Nobody has called me in 50 years. And by the way, everything you think you know about this study is wrong,' or 'The story is not what it seems.'"

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An Asian elephant named Mary living at the Berlin Zoo surprised researchers by figuring out how to use a hose to take her morning showers, according to a new paper published in the journal Current Biology. “Elephants are amazing with hoses,” said co-author Michael Brecht of the Humboldt University of Berlin. “As it is often the case with elephants, hose tool use behaviors come out very differently from animal to animal; elephant Mary is the queen of showering.”

Tool use was once thought to be one of the defining features of humans, but examples of it were eventually observed in primates and other mammals. Dolphins have been observed using sea sponges to protect their beaks while foraging for food, and sea otters will break open shellfish like abalone with rocks. Several species of fish also use tools to hunt and crack open shellfish, as well as to clear a spot for nesting. And the coconut octopus collects coconut shells, stacking them and transporting them before reassembling them as shelter.

Birds have also been observed using tools in the wild, although this behavior was limited to corvids (crows, ravens, and jays), although woodpecker finches have been known to insert twigs into trees to impale passing larvae for food. Parrots, by contrast, have mostly been noted for their linguistic skills, and there has only been limited evidence that they use anything resembling a tool in the wild. Primarily, they seem to use external objects to position nuts while feeding.

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People have long been fascinated by the haunting plaster casts of the bodies of people who died in Pompeii when Mount Vesuvius erupted in 79 CE. Archaeologists have presented certain popular narratives about who these people might have been and how they might have been related. But ancient DNA analysis has revealed that those preferred narratives were not entirely accurate and may reflect certain cultural biases, according to a new paper published in the journal Current Biology. The results also corroborate prior research suggesting that the people of ancient Pompeii were the descendants of immigrants from the Eastern Mediterranean.

As previously reported, the eruption of Mount Vesuvius released thermal energy roughly equivalent to 100,000 times the atomic bombs dropped on Hiroshima and Nagasaki at the end of World War II, spewing molten rock, pumice, and hot ash over the cities of Pompeii and Herculaneum in particular. The vast majority of people in Pompeii and Herculaneum—the cities hardest hit—perished from asphyxiation, choking on the thick clouds of noxious gas and ash. But at least some of the Vesuvian victims probably died instantaneously from the intense heat of fast-moving lava flows, with temperatures high enough to boil brains and explode skulls.

In the first phase, immediately after the eruption, a long column of ash and pumice blanketed the surrounding towns, most notably Pompeii and Herculaneum. By late night or early morning, pyroclastic flows (fast-moving hot ash, lava fragments, and gases) swept through and obliterated what remained, leaving the bodies of the victims frozen in seeming suspended action.

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Since the 1940s, baseball players have been spreading a special kind of "magic mud" on new baseballs to reduce the slick, glossy shine and give pitchers a firmer grip. Now, scientists at the University of Pennsylvania have identified just what gives that magic mud its special properties, according to a new paper published in the Proceedings of the National Academy of Sciences.

Before magic mud came along, baseballs were treated with a mix of water and soil from the infield or, alternatively, tobacco juice or shoe polish. But these substances stained and scratched up the ball's leather surface. Lena Blackburne was a third-base coach for the Philadelphia Athletics in the 1930s when an umpire complained about that, so he hunted for a better mud. Blackburne found that mud in a still-secret location purportedly near Palmyra, New Jersey, and a baseball dynasty was born: Lena Blackburne Baseball Rubbing Mud. Once harvested, the mud is strained, skimmed of excess water, rinsed with tap water, and then subjected to a secret "proprietary treatment" before being allowed to settle.

Yet there hasn't been much scientific research on the magic mud apart from one 2022 study. We do know quite a bit about the complex behavior of soil in general, including mud. Per the authors, mud is essentially "a dense suspension of predominantly clay and silt particles in water," sometimes with a bit of sand in the mix, although this has little effect on how mud behaves under shearing forces (rheology). Technically, it falls into the non-Newtonian fluid category, in which the viscosity changes (either thickening or thinning) in response to an applied strain or shearing force, thereby straddling the boundary between liquid and solid behavior.

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The story of Arctic explorer Ernest Shackleton's failed 1914 expedition to be the first to traverse the continent of Antarctica has long captured the popular imagination, as have the various efforts to locate the wreckage of his ship, the Endurance. The ship was finally found in 2022, nearly 107 years after it sank beneath the ice. The stories of Shackleton's adventures and the 2022 expedition are told in parallel in Endurance, a new documentary from National Geographic now streaming on Disney+.

Endurance is directed by Oscar winners Jimmy Chin and Chai Vasarhelyi (Free Solo). According to Vasarhelyi, she and Chin had been obsessed with the Shackleton story for a long time. The discovery of the shipwreck in 2022 gave them the perfect opportunity to tell the story again for a new audience, making use of all the technological advances that have been made in recent years.

"I think the Shackleton story is at the heart of the DNA of our films," Vasarhelyi told Ars. "It's the greatest human survival story ever. It really speaks to having these audacious objectives and dreams. When everyone tells you that you can't, you want to do it anyway. It requires you to then have the actual courage, grit, discipline, and strength of character to see it through. Shackleton is that story. He didn't sensibly achieve any of his goals, but through his failure he found his strength: being able to inspire the confidence of his men."

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Henry VIII's favorite warship, the Mary Rose, sank in battle in 1545. Archaeologists successfully raised the ship in 1982, along with thousands of articles and the remains of 179 crew members—all remarkably well preserved thanks to the anaerobic conditions of the shipwreck created by the layers of soft sediment that accumulated over the wreckage.

A new analysis of some of the recovered bones reveals that whether someone is right- or left-handed could affect how their collarbone chemistry changes as they age, according to a new paper published in the journal PLoS ONE. This has implications for our understanding not just of aging, but of bone conditions like fracture risk and osteoarthritis.

As previously reported, the earliest-known reference to the Mary Rose appears in a January 29, 1510, letter ordering the construction of two new ships for the young king: the Mary Rose and her sister ship, dubbed the Peter Pomegranate. Once the newly built ship had launched, Henry VIII wasted no time defying his advisers and declaring war on France in 1512. The Mary Rose served the monarch well through that conflict, as well as during a second war with the French that ran roughly from 1522 through 1525, after which it underwent a substantial overhaul.

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Many animals, including humans, have developed a taste for alcohol in some form, but excessive consumption often leads to adverse health effects. One exception is the Oriental hornet. According to a new paper published in the Proceedings of the National Academy of Sciences, these hornets can guzzle seemingly unlimited amounts of ethanol regularly and at very high concentrations with no ill effects—not even intoxication. They pretty much drank honeybees used in the same experiments under the table.

“To the best of our knowledge, Oriental hornets are the only animal in nature adapted to consuming alcohol as a metabolic fuel," said co-author Eran Levin of Tel Aviv University. "They show no signs of intoxication or illness, even after chronically consuming huge amounts of alcohol, and they eliminate it from their bodies very quickly."

Per Levin et al., there's a "drunken monkey" theory that predicts that certain animals well-adapted to low concentrations of ethanol in their diets nonetheless have adverse reactions at higher concentrations. Studies have shown that tree shrews, for example, can handle concentrations of up to 3.8 percent, but in laboratory conditions, when they consumed ethanol in concentrations of 10 percent or higher, they were prone to liver damage.

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