Archaeology – Page 3

Oldest wooden tools in East Asia may have come from any of three species

ancient people did stuff, Archaeology, Denisovans, hominins, homo erectus, Homo heidelbergensis, Science, wooden tools / DJ Henderson / July 7, 2025

That leaves a few possibilities: Denisovans, Homo heidelbergensis (the common ancestor of Neanderthals, Denisovans, and our species), or Homo erectus. All three species could have lived in the area at the time. But nobody at Gantangqing left behind any convenient, readily identifiable bones along with their wooden tools, stone tools, and butchered animal bones (so inconsiderate of them), making it hard to pin down exactly which species these 300,000-year-old hunter-gatherers belonged to.

Homo erectus had been in Asia for more than a million years by the time Gantangqing’s lakeshore was occupied; the oldest Homo erectus fossils in Asia are from Indonesia and date back 1.8 million years. They also stuck around until quite recently. In caves at a site called Zhoukoudian, outside Beijing in eastern China, Homo erectus remains date to sometime between 700,000 and 200,000 years ago (there’s still a lot of debate on exactly how old the site is).

All of that means that Homo erectus’ presence in the region overlaps the age of the wood tools at Gantangqing. And the stone tools found nearby are fairly simple cores and flakes that don’t rule out Homo erectus as their makers. Archaeologists haven’t unearthed evidence of Homo erectus making or using sophisticated wooden tools like this, but for a species that managed to harness fire and cross miles of ocean, it’s not too wild a speculation.

On the other hand, we know that Denisovans were probably in the area, too, or at least not too far away. A recently identified Denisovan skull from Harbin, China, is 146,000 years old but bears a striking resemblance to other hominin skulls from sites all over China, which range from 300,000 to 200,000 years old. And making finely crafted wooden tools fits with everything we know about Denisovan capabilities.

Then there’s Homo heidelbergensis, the direct ancestor of Denisovans. In fact, it’s a little hard to tell where hominins stop being Homo heidelbergensis and start being Denisovans, or even whether the distinction matters. It’s a problem paleoanthropologists refer to as the “muddle in the Middle,” since both species date to the Middle Pleistocene. So if Homo erectus and Denisovans are in the running, so is Homo heidelbergensis, by default.

And unless someone finds a telltale skull nearby or another very similar toolkit at a site with telltale skulls to consult, we may not know for sure.

Science, 2023. DOI: 10.1126/science.adr8540 (About DOIs).

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A mammoth tusk boomerang from Poland is 40,000 years old

ancient people did stuff, Archaeology, boomerangs, mammoth, paleolithic, paleolithic europe, radiocarbon dating, Science / Beth Washington / July 1, 2025

A boomerang carved from a mammoth tusk is one of the oldest in the world, and it may be even older than archaeologists originally thought, according to a recent round of radiocarbon dating.

Archaeologists unearthed the mammoth-tusk boomerang in Poland’s Oblazowa Cave in the 1990s, and they originally dated it to around 18,000 years old, which made it one of the world’s oldest intact boomerangs. But according to recent analysis by University of Bologna researcher Sahra Talamo and her colleagues, the boomerang may have been made around 40,000 years ago. If they’re right, it offers tantalizing clues about how people lived on the harsh tundra of what’s now Poland during the last Ice Age.

A boomerang carved from mammoth tusk

The mammoth-tusk boomerang is about 72 centimeters long, gently curved, and shaped so that one end is slightly more rounded than the other. It still bears scratches and scuffs from the mammoth’s life, along with fine, parallel grooves that mark where some ancient craftsperson shaped and smoothed the boomerang. On the rounded end, a series of diagonal marks would have made the weapon easier to grip. It’s smoothed and worn from frequent handling: the last traces of the life of some Paleolithic hunter.

Based on experiments with a replica, the Polish mammoth boomerang flies smoothly but doesn’t return, similar to certain types of Aboriginal Australian boomerangs. In fact, it looks a lot like a style used by Aboriginal people from Queensland, Australia, but that’s a case of people in different times and places coming up with very similar designs to fit similar needs.

But critically, according to Talamo and her colleagues, the boomerang is about 40,000 years old.

That’s a huge leap from the original radiocarbon date, made in 1996, which was based on a sample of material from the boomerang itself and estimated an age of 18,000 years. But Talamo and her colleagues claim that original date didn’t line up well with the ages of other nearby artifacts from the same layer of the cave floor. That made them suspect that the boomerang sample may have gotten contaminated by modern carbon somewhere along the way, making it look younger. To test the idea, the archaeologists radiocarbon dated samples from 13 animal bones—plus one from a human thumb—unearthed from the same layer of cave floor sediment as the boomerang.

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Testing ancient Paleolithic migration with a replica canoe

anthropology, Archaeology, experimental archaeology, paleolithic, Science / Shannon Garcia / June 26, 2025

(Left) GPS tracking and modeling of ocean currents toward the end of the experimental voyage. (Right) The team on the water around the time of the left image. Credit: Kaifu et al., 2025/CC-By-ND

At the 30-hour mark, the captain ordered the entire crew to rest, letting the dugout drift freely for a while, which fortunately brought them closer to Yonaguni Island. At hour 40, the island’s silhouette was visible, and over the next five hours, the crew was able to navigate the strong tidal flow along the coast until they reached their landing site: Nama Beach. So the experimental voyage was a success, augmented by the numerical simulations to demonstrate that the boat could make similar voyages from different departure points across both modern and late-Pleistocene oceans.

Granted, it was not possible to recreate Paleolithic conditions perfectly on a modern ocean. The crew first spotted the island because of its artificial lights, although by that time, they were on track navigationally. They were also accompanied by escort ships to ensure the crew’s safety, supplying fresh water twice during the voyage. But the escort ships did not aid with navigation or the dugout captain’s decision-making, and the authors believe that any effects were likely minimal. The biggest difference was the paddlers’ basic modern knowledge of local geography, which helped them develop a navigation plan—an unavoidable anachronism, although the crew did not rely on compasses, GPS, or watches during the voyage.

“Scientists try to reconstruct the processes of past human migrations, but it is often difficult to examine how challenging they really were,” said Kaifu. “One important message from the whole project was that our Paleolithic ancestors were real challengers. Like us today, they had to undertake strategic challenges to advance. For example, the ancient Polynesian people had no maps, but they could travel almost the entire Pacific. There are a variety of signs on the ocean to know the right direction, such as visible land masses, heavenly bodies, swells and winds. We learned parts of such techniques ourselves along the way.”

DOI: “Traversing the Kuroshio: Paleolithic migration across one of the world’s strongest ocean currents,” Science Advances, 2025. 10.1126/sciadv.adv5508 (About DOIs).

DOI: “Palaeolithic seafaring in East Asia: an experimental test of the dugout canoe hypothesis,” Science Advances, 2025. 10.1126/sciadv.adv5507 (About DOIs).

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Sailing the fjords like the Vikings yields unexpected insights

Archaeology, experimental archaeology, Science, viking ships, vikings / Shannon Garcia / June 23, 2025

“On we sweep with threshing oar”

Greer Jarrett has identified four possible small ports, or “havens,” used by Vikings along the Norwegian coast.

Experimental archaeologist Greer Jarrett of Lund University in Sweden has been sailing in the footsteps of Vikings for the last three years.

If you want to learn more about how and where the Vikings sailed, making the journey through the fjords yourself in replica boats is a practical, hands-on approach to achieving that end. Greer Jarrett, an archaeologist at Lund University in Sweden, has spent the last three years doing just that, sailing more than 5,000 kilometers along known Viking trade routes in open, spare-rigged clinker boats similar to those used by the Vikings.

Not only has Jarrett learned a great deal about the boats themselves, he also identified four possible havens along the Norwegian coast, part of what may have been a decentralized network that played a crucial role in trade and travel during that period. And those ports are located farther out to sea than other major ports and hubs known to date, according to a paper he published in the Journal of Archaeological Method and Theory.

It’s just the latest intriguing discovery enabled by the growing field of experimental archaeology, whereby researchers seek to reverse-engineer all manner of ancient technologies. Experimental archaeologists have, for instance, built their own versions of Early Upper Paleolithic adzes, axes, and chisels. The resulting fractures and wear enabled them to develop new criteria for identifying the likely functions of ancient tools. Others have tried to cook like the Neanderthals, concluding that flint flakes were surprisingly effective for butchering birds, and that roasting the birds damages the bones to such an extent that it’s unlikely they would be preserved in the archaeological record.

Kent State University’s Metin Eren has done practical experiments to study, for instance, the trajectories of atlatls attached to spears tipped with replica Clovis points, and how their performance compares to javelins used by Neanderthals. He even fashioned rudimentary blades out of his own frozen feces to test whether they could cut through pig hide, muscle, and tendon—solely to test a famous anthropological legend about an elderly Inuit man in the 1950s who purportedly did the same to kill and skin a dog, using its rib cage as a makeshift sled to venture off into the Arctic. (It did not work, so myth: busted. But it did snag Eren an Ig Nobel prize.)

Taking a hands-on, experimental archaeological approach to studying the Vikings makes sense in light of the dearth of contemporary written sources. “We have a few things written by outsiders, but there’s very, very few accounts written or delivered by people from Scandinavia during that period,” Jarrett told Ars. “We normally rely on indirect forms of evidence, be that genetics or archaeology or linguistics, which show strong, very frequent connections across maritime areas in the North Atlantic. But because traveling by boat is kind of an archaeologically invisible act, you don’t leave any footprints. So we have very little information about the voyages between these points.”

The sailing voyages made by Greer Jarrett during the research project. The image also shows the four possible Viking harbours identified by Jarrett. — The sailing voyages made by Greer Jarrett during the research project, as well as the four possible Viking harbors he identified. Credit: Greer Jarrett

Garrett and his crew used four or five different replica boats for their test voyages. Most were built by volunteers, enthusiasts, or students Jarrett had met during his considerable time in the field. They then sailed along the west coast of the Scandinavian Peninsula, a core area of Viking seafaring.

“These are reconstructions of traditional Norwegian boats from the 1800s and early 1900s,” said Jarrett. “My idea was, because of this really long-term continuity in traditional boat building practices, especially in Norway, it might be possible to use these later boats which have lots of similarities to try and work out the potentials of where people might have gotten out. It’s the idea of suggesting potentials based on practical experience to try and join those dots between the different evidence we have across the Viking world.”

That decision has led to some criticism from colleagues because of the enormous gap in time, but Jarrett defends his choice. “The Viking Age ends in the 11th century, and we’re talking about boats from 800 years later,” he said. “But the construction techniques and the way they are rigged and their general performance characteristics are similar enough. Because this is a project about voyages and not a project about boat building, it seemed like a defensible analogy.”

Seeking safe harbor

“On the long-range voyages, we worked in watches of four hours on and four hours off, and that is just about long enough to get some sleep on your off watch, but also just about short enough that you don’t get really, really, really cold, which is obviously a risk,” said Jarrett. “It was manageable, but we looked like penguins. I mean, we’re wearing six layers of wool at any time and sleeping all stacked together for warmth. But other times it’s really nice. The spring and the autumn in Scandinavia, there’s much more likelihood of high-pressure cycles, which means that it’s clearer and sunnier than in the summer itself.”

Nonetheless, there were some rough moments, such as when the mast spar holding up the mainsail snapped, forcing the crew to improvise and lash two oars together to hold the sail so they could continue their journey. It took several days to repair the boat so it could sail again. There was no safety boat following along in case the crew got into trouble, and no engine, although they did have a life raft, which the crew has yet to use.

Based on his sailing trials, Jarrett believes that the Vikings had no need for navigational tools like maps, a compass, or a sextant, relying instead on what he calls “mental maps”—or a “maritime cultural mindscape”—based on sailors’ memories and experiences passed down orally through generations. Those maps might also be informed by the myths linked to well-known coastal landmarks, such as skerries, small islets, or reefs.

“People had been moving by boat along the west coast of Scandinavia for a really, really, really long time, probably since the late Neolithic, if not earlier—thousands of years before the Viking age,” said Jarrett. “There are big trading networks in place beforehand, and that is reflected in the names, place names along the west coast. My primary argument is if you spend 3,000 years traveling up and down a coastline in which you can use the coast at all times for navigation, then it’s unnecessary to develop instrumentation.”

“Instruments are used when you are in a place out in the open sea that you don’t know,” Jarrett continued. “We definitely know they didn’t have compasses because those don’t arrive from China until the 1200s. There are these ideas about sunstones and sundials, or little sun compasses, which are entirely possible. But there’s no legitimate proof of either of them archaeologically yet. I may well be proved wrong if we find them at some point, but I don’t think they’re necessary for this at all.”

Based on the sailing trials, archaeological and documentary evidence of Viking Age maritime centers, and digital reconstructions of past sea levels. Jarrett was able develop a useful set of criteria for evaluating potential havens. For instance, the site should be reachable in low visibility, with land or sea marks that sailors could use as bearings; large enough to accommodate multiple vessels of at least the size of a fyring (which can house a crew of four to 10 people); provide good protection from sea swell and storm surges; and have access to fresh water, among other criteria. Four sites scored sufficiently high by those criteria to qualify as possible Viking havens.

The four sites are Smørhamn, located at the confluence of Oldersund and the Frøysjø, where an inn and trading post are known to have existed since at least the late 17th century; the archipelago of Sørøyane between Stad and Ålesund, near where the sea battle of Hjörungavágr was fought circa 986 CE; Bjørnsund, a number of small islands off the southwestern tip of Hustadvika; and the island of Storfosna, which appears on 16th and 17th century charts.

“I’m not saying, ‘This is where they went,'” said Jarrett. “I’m saying that, with these kinds of boats under these conditions, it would be possible to go to these places. And it’s much more difficult—not impossible, but much more difficult—to go to these other places or to sail in these other conditions.”

Pining for the fjords

The next step is for Jarrett and other archaeologists to hunt for evidence in support of his hypothesis. “Most of these sites have never been excavated,” said Jarrett. “There’s been a long assumption that these are landing places with the idea that you are dragging your boat ashore. I’m very opposed to that idea because these are two-and-a-half-ton boats, let alone the cargo. Unless you have a team of oxen and 20 people at your command, there is no way you’re getting them on the beach. I’m very convinced that these places have jetties and mooring posts likely preserved underwater. All of that organic material survives much better underwater than it does on land. So I think that’s very possible.”

They might also find smaller items suggestive of a thriving harbor community. “Whenever you go into land, you’ve got something that’s broken, so you need to do repairs,” said Jarrett. “So things like clink nails or piles of balustones or signs of smithing—the typical kind of things you’d use for repairing your ship, I think are possible to find.” Jarrett’s methodology might also prove useful for studying other seafaring communities.

The practical experience of sailing the same seas as the Vikings naturally led to some surprising insights. “You are able to ask very different questions the minute you walk away from your desk and get on a boat,” said Jarrett. “I think it’s essential to do that because you think in new ways. In terms of the results themselves, the boats are extremely seaworthy crafts. When you get in them for the first time, you don’t think that, because they’re very, very light. They feel very flimsy, and they’re very low in the water compared to a modern sailing boat. So you feel really in touch with the wave, which is kind of scary. But because they’re so flexible and because of the way they’re rigged, they’re actually really stable, even in big waves.”

“We kept going out thinking, ‘Oh, this is maybe the limit of what this boat can tolerate,’ and then it would be fine, and we’d be, ‘Okay, let’s go a little bit in slightly bigger waves with slightly stronger wind,'” Jarrett continued. “So I think our comfort zones definitely visibly expanded during that period. And I had the chance to work with the same crews over three years. By the end of those three years, we were doing stuff that we would never have been able to do at the beginning.”

Another big difference from modern boats, Jarrett discovered, is that one cannot sail a traditional Viking craft alone. “It has to be a collaborative effort because of how you need a person at the front and the back of the boat basically at all times,” he said. “So developing the crew together and gaining not only skills, but also trust between us meant that we could do things in 2024 that seemed completely insane just a couple of years earlier. I cannot imagine what that is like if you have an entire lifetime of Viking sailors working together for 30 years. It must be an incredible way of creating social bonds.”

DOI: Journal of Archaeological Method and Theory, 2025. 10.1007/s10816-025-09708-6 (About DOIs).

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

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New dating for White Sands footprints confirms controversial theory

Archaeology, geology, Science, White Sands footprints / Kelly Newman / June 19, 2025

Some of the sediment layers contained the remains of ancient grass seeds mixed with the sediment. Bennett and his colleagues radiocarbon-dated seeds from the layer just below the oldest footprints and the layer just above the most recent ones. According to those 2021 results, the oldest footprints were made sometime after 23,000 years ago; the most recent ones were made sometime before 21,000 years ago.

At that time, the northern half of the continent was several kilometers below massive sheets of ice. The existence of 23,000-year-old footprints could only mean that people were already living in what’s now New Mexico before the ice sheets sealed off the southern half of the continent from the rest of the world for the next few thousand years.

Ancient human footprints found in situ at at White Sands National Park in New Mexico. — Ancient human footprints found in situ at White Sands National Park in New Mexico. Credit: Jeffrey S. Pigati et al., 2023

Other researchers were skeptical of those results, pointing out that the aquatic plants (Ruppia cirrhosa) analyzed were prone to absorbing the ancient carbon in groundwater, which could have skewed the findings and made the footprints seem older than they actually were. And the pollen samples weren’t taken from the same sediment layers as the footprints.

So the same team followed up by radiocarbon-dating pollen sampled from the same layers as some of the footprints—those that weren’t too thin for sampling. This pollen came from pine, spruce, and fir trees, i.e., terrestrial plants, thereby addressing the issue of groundwater carbon seeping into samples. They also analyzed quartz grains taken from clay just above the lowest layer of footprints using a different method, optically stimulated luminescence dating. They published those findings in 2023, which agreed with their earlier estimate.

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We’ve had a Denisovan skull since the 1930s—only nobody knew

ancient DNA, ancient proteins, anthropology, Archaeology, Denisovans, hominins, Neanderthals, paleoanthropology, paleoproteomics, proteomics, Science, skeletons and skeleton accessories, skulls / Mike M. / June 18, 2025

It’s a Denisovan? Always has been.

After years of mystery, we now know what at least one Denisovan looked like.

A 146,000-year-old skull from Harbin, China, belongs to a Denisovan, according to a recent study of proteins preserved inside the ancient bone. The paleoanthropologists who studied the Harbin skull in 2021 declared it a new (to us) species, Homo longi. But the Harbin skull still contains enough of its original proteins to tell a different story: A few of them matched specific proteins from Denisovan bones and teeth, as encoded in Denisovan DNA.

So Homo longi was a Denisovan all along, and thanks to the remarkably well-preserved skull, we finally know what the enigmatic Denisovans actually looked like.

Two early-human skulls against a black background. — Credit: Ni et al. 2021

The Harbin skull (left) and the Dali skull (right).

Unmasking Dragon Man

Paleoanthropologist Qiang Ji, of the Chinese Academy of Sciences, and colleagues tried to sequence ancient DNA from several samples of the Harbin skull’s bone and its one remaining tooth, but they had no luck. Proteins tend to be hardier molecules than DNA, though, and in samples from the skull’s temporal bone (the ones on the sides of the head, just behind the cheekbones), the researchers struck pay dirt.

They found fragments of a total of 95 proteins. Four of these had variations that were distinct to the Denisovan lineage, and the Harbin skull matched Denisovans on three of them. That’s enough to confidently say that the Harbin skull had belonged to a Denisovan. So for the past few years, we’ve had images of an almost uncannily well-preserved Denisovan skull—which is a pretty big deal, especially when you consider its complicated history.

While the world is now aware of it, until 2021, only one person had known what the skull looked like since its discovery in the 1930s. It was unearthed in Harbin, in northeast China, during the Japanese occupation of the area. Not wanting it to be seized by the occupying government, the person who found the skull immediately hid it, and he kept it hidden for most of the rest of his life.

He eventually turned it over to scientists in 2018, who published their analysis in 2021. That analysis placed the Harbin skull, along with a number of other fossils from China, in a distinct lineage within our genus, Homo, making them our species’ closest fossil relatives. They called this alleged new species Homo longi, or “Dragon Man.”

The decision to classify Homo longi as a new species was largely due to the skull’s unique combination of features (which we’ll discuss below). But it was a controversial decision, partly because paleoanthropologists don’t entirely agree about whether we should even call Neanderthals a distinct species. If the line between Neanderthals and our species is that blurry, many in the field have questioned whether Homo longi could be considered a distinct species, when it’s even closer to us than the Neanderthals.

Meanwhile, the 2021 paper also left room for debate on whether the skull might actually have belonged to a Denisovan rather than a distinct new species. Its authors acknowledge that one of the fossils they label as Homo longi had already been identified as a Denisovan based on its protein sequences. They also point out that the Harbin skull has rather large molars, which seem to be a common feature in Denisovans.

The paper’s authors argued that their Homo longi should be a separate branch of the hominin lineage, more closely related to us than to Denisovans or Neanderthals. But if the Harbin skull looked so much like Denisovan fossils and so little like fossils from our species, the alleged relationship begins to look pretty dubious. In the end, the 2021 paper’s authors dodged the issue by saying that “new genetic material will test the relationship of these populations to each other and to the Denisovans.”

Which turned out to be exactly what happened.

A ghost lineage comes to life

Denisovans are the ghost in our family tree. For scientists, a “ghost lineage” is one that’s known mostly from genetic evidence, not fossils; like a ghost, it has a presence we can sense but no physical form we can touch. With the extremely well-preserved Harbin skull identified as a Denisovan, though, we’re finally able to look our “ghost” cousins in the face.

Paleogeneticists have recovered Denisovan DNA from tiny fragments of bone and teeth, and even from the soil of a cave floor. Genomics researchers have found segments of Denisovan DNA woven into the genomes of some modern humans, revealing just how close our two species once were. But the handful of Denisovan fossils paleoanthropologists have unearthed are mostly small fragments—a finger bone here, a tooth there, a jawbone someplace else—that don’t reveal much about how Denisovans lived or what they looked like.

We know they existed and that they were something slightly different from Homo sapiens or Neanderthals. We even know when and where they lived and a surprising amount about their genetics, and we have some very strong hints about how they interacted with our species and with Neanderthals. But we didn’t really know what they looked like, and we couldn’t hope to identify their fossils without turning to DNA or protein sequences.

Until now.

Neanderthals and Denisovans probably enjoyed the view from Denisova Cave, too. Credit: loronet / Flickr

The face of a Denisovan

So what did a Denisovan look like? Harbin 1 has a wide, flattish face with small cheekbones, big eye sockets, and a heavy brow. Its upper jaw juts forward just a little, and it had big, robust molars. The cranium itself is longer and less dome-like than ours, but it’s roomy enough for a big brain (about 1,420 millimeters).

Some of those traits, like the large molars and the long, low cranium, resemble those of earlier hominin species such as Homo erectus or Homo heidelbergensis. Others, like a relatively flat face, set beneath the cranium instead of sticking out in front of it, look more like us. (Early hominins, like Australopithecus afarensis, don’t really have foreheads because their skulls are arranged so their brains are right behind their faces instead of partly above them, like ours.)

In other words, Harbin’s features are what paleoanthropologists call a mosaic, with some traits that look like they come from older lineages and some that seem more modern. Mosaics are common in the hominin family tree.

But for all the detail it reveals about the Denisovans, Harbin is still just one skull from one individual. Imagine trying to reconstruct all the diversity of human faces from just one skull. We have to assume that Densiovans—a species that spanned a huge swath of our planet, from Siberia to Taiwan, and a wide range of environments, from high-altitude plateaus in Tibet to subtropical forests—were also a pretty diverse species.

It’s also worth remembering that the Harbin skull is exactly that: a skull. It can’t tell us much about how tall its former user was, how they were built, or how they moved or worked during their life. We can’t even say for sure whether Harbin is osteologically or genetically male or female. In other words, some of the mystery of the Denisovans still endures.

What’s next?

In the 2021 papers, the researchers noted that the Harbin skull also bears a resemblance to a 200,000- to 260,000-year-old skull found in Dali County in northwestern China, a roughly 300,000-year-old skull found in Hualong Cave in eastern China, and a 260,000-year-old skull from Jinniushi (sometimes spelled Jinniushan) Cave in China. And some fossils from Taiwan and northern China have molars that look an awful lot like those in that Tibetan jawbone.

“These hominins potentially also belong to Denisovan populations,” write Ji and colleagues. That means we might already have a better sample of Denisovan diversity than this one skull suggests.

And, like the Harbin skull, the bones and teeth of those other fossils may hold ancient DNA or proteins that could help confirm that intriguing possibility.

Science, 2023 DOI: 10.1126/science.adu9677 (About DOIs).

Kiona is a freelance science journalist and resident archaeology nerd at Ars Technica.

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Research roundup: 7 stories we almost missed

acoustics, Archaeology, architecture, Biology, Physics, primates, robotics, Science / Shannon Garcia / June 1, 2025

Ping-pong bots, drumming chimps, picking styles of two jazz greats, and an ancient underground city’s soundscape

Time lapse photos show a new ping-pong-playing robot performing a top spin. Credit: David Nguyen, Kendrick Cancio and Sangbae Kim

It’s a regrettable reality that there is never time to cover all the interesting scientific stories we come across each month. In the past, we’ve featured year-end roundups of cool science stories we (almost) missed. This year, we’re experimenting with a monthly collection. May’s list includes a nifty experiment to make a predicted effect of special relativity visible; a ping-pong playing robot that can return hits with 88 percent accuracy; and the discovery of the rare genetic mutation that makes orange cats orange, among other highlights.

Special relativity made visible

The Terrell-Penrose-Effect: Fast objects appear rotated — Credit: TU Wien

Perhaps the most well-known feature of Albert Einstein’s special theory of relativity is time dilation and length contraction. In 1959, two physicists predicted another feature of relativistic motion: an object moving near the speed of light should also appear to be rotated. It’s not been possible to demonstrate this experimentally, however—until now. Physicists at the Vienna University of Technology figured out how to reproduce this rotational effect in the lab using laser pulses and precision cameras, according to a paper published in the journal Communications Physics.

They found their inspiration in art, specifically an earlier collaboration with an artist named Enar de Dios Rodriguez, who collaborated with VUT and the University of Vienna on a project involving ultra-fast photography and slow light. For this latest research, they used objects shaped like a cube and a sphere and moved them around the lab while zapping them with ultrashort laser pulses, recording the flashes with a high-speed camera.

Getting the timing just right effectively yields similar results to a light speed of 2 m/s. After photographing the objects many times using this method, the team then combined the still images into a single image. The results: the cube looked twisted and the sphere’s North Pole was in a different location—a demonstration of the rotational effect predicted back in 1959.

DOI: Communications Physics, 2025. 10.1038/s42005-025-02003-6 (About DOIs).

Drumming chimpanzees

A chimpanzee feeling the rhythm. Credit: Current Biology/Eleuteri et al., 2025.

Chimpanzees are known to “drum” on the roots of trees as a means of communication, often combining that action with what are known as “pant-hoot” vocalizations (see above video). Scientists have found that the chimps’ drumming exhibits key elements of musical rhythm much like humans, according to a paper published in the journal Current Biology—specifically non-random timing and isochrony. And chimps from different geographical regions have different drumming rhythms.

Back in 2022, the same team observed that individual chimps had unique styles of “buttress drumming,” which served as a kind of communication, letting others in the same group know their identity, location, and activity. This time around they wanted to know if this was also true of chimps living in different groups and whether their drumming was rhythmic in nature. So they collected video footage of the drumming behavior among 11 chimpanzee communities across six populations in East Africa (Uganda) and West Africa (Ivory Coast), amounting to 371 drumming bouts.

Their analysis of the drum patterns confirmed their hypothesis. The western chimps drummed in regularly spaced hits, used faster tempos, and started drumming earlier during their pant-hoot vocalizations. Eastern chimps would alternate between shorter and longer spaced hits. Since this kind of rhythmic percussion is one of the earliest evolved forms of human musical expression and is ubiquitous across cultures, findings such as this could shed light on how our love of rhythm evolved.

DOI: Current Biology, 2025. 10.1016/j.cub.2025.04.019 (About DOIs).

Distinctive styles of two jazz greats

Wes Montgomery (left)) and Joe Pass (right) playing guitars

Jazz lovers likely need no introduction to Joe Pass and Wes Montgomery, 20th century guitarists who influenced generations of jazz musicians with their innovative techniques. Montgomery, for instance, didn’t use a pick, preferring to pluck the strings with his thumb—a method he developed because he practiced at night after working all day as a machinist and didn’t want to wake his children or neighbors. Pass developed his own range of picking techniques, including fingerpicking, hybrid picking, and “flat picking.”

Chirag Gokani and Preston Wilson, both with Applied Research Laboratories and the University of Texas, Austin, greatly admired both Pass and Montgomery and decided to explore the underlying the acoustics of their distinctive playing, modeling the interactions of the thumb, fingers, and pick with a guitar string. They described their research during a meeting of the Acoustical Society of America in New Orleans, LA.

Among their findings: Montgomery achieved his warm tone by playing closer to the bridge and mostly plucking at the string. Pass’s rich tone arose from a combination of using a pick and playing closer to the guitar neck. There were also differences in how much a thumb, finger, and pick slip off the string: use of the thumb (Montgomery) produced more of a “pluck” compared to the pick (Pass), which produced more of a “strike.” Gokani and Wilson think their model could be used to synthesize digital guitars with a more realistic sound, as well as helping guitarists better emulate Pass and Montgomery.

Sounds of an ancient underground city

A collection of images from the underground tunnels of Derinkuyu. — Credit: Sezin Nas

Turkey is home to the underground city Derinkuyu, originally carved out inside soft volcanic rock around the 8th century BCE. It was later expanded to include four main ventilation channels (and some 50,000 smaller shafts) serving seven levels, which could be closed off from the inside with a large rolling stone. The city could hold up to 20,000 people and it was connected to another underground city, Kaymakli, via tunnels. Derinkuyu helped protect Arab Muslims during the Arab-Byzantine wars, served as a refuge from the Ottomans in the 14th century, and as a haven for Armenians escaping persecution in the early 20th century, among other functions.

The tunnels were rediscovered in the 1960s and about half of the city has been open to visitors since 2016. The site is naturally of great archaeological interest, but there has been little to no research on the acoustics of the site, particularly the ventilation channels—one of Derinkuyu’s most unique features, according to Sezin Nas, an architectural acoustician at Istanbul Galata University in Turkey. She gave a talk at a meeting of the Acoustical Society of America in New Orleans, LA, about her work on the site’s acoustic environment.

Nas analyzed a church, a living area, and a kitchen, measuring sound sources and reverberation patterns, among other factors, to create a 3D virtual soundscape. The hope is that a better understanding of this aspect of Derinkuyu could improve the design of future underground urban spaces—as well as one day using her virtual soundscape to enable visitors to experience the sounds of the city themselves.

MIT’s latest ping-pong robot

Robots playing ping-pong have been a thing since the 1980s, of particular interest to scientists because it requires the robot to combine the slow, precise ability to grasp and pick up objects with dynamic, adaptable locomotion. Such robots need high-speed machine vision, fast motors and actuators, precise control, and the ability to make accurate predictions in real time, not to mention being able to develop a game strategy. More recent designs use AI techniques to allow the robots to “learn” from prior data to improve their performance.

MIT researchers have built their own version of a ping-pong playing robot, incorporating a lightweight design and the ability to precisely return shots. They built on prior work developing the Humanoid, a small bipedal two-armed robot—specifically, modifying the Humanoid’s arm by adding an extra degree of freedom to the wrist so the robot could control a ping-pong paddle. They tested their robot by mounting it on a ping-pong table and lobbing 150 balls at it from the other side of the table, capturing the action with high-speed cameras.

The new bot can execute three different swing types (loop, drive, and chip) and during the trial runs it returned the ball with impressive accuracy across all three types: 88.4 percent, 89.2 percent, and 87.5 percent, respectively. Subsequent tweaks to theirrystem brought the robot’s strike speed up to 19 meters per second (about 42 MPH), close to the 12 to 25 meters per second of advanced human players. The addition of control algorithms gave the robot the ability to aim. The robot still has limited mobility and reach because it has to be fixed to the ping-pong table but the MIT researchers plan to rig it to a gantry or wheeled platform in the future to address that shortcoming.

Why orange cats are orange

Cat lovers know orange cats are special for more than their unique coloring, but that’s the quality that has intrigued scientists for almost a century. Sure, lots of animals have orange, ginger, or yellow hues, like tigers, orangutans, and golden retrievers. But in domestic cats that color is specifically linked to sex. Almost all orange cats are male. Scientists have now identified the genetic mutation responsible and it appears to be unique to cats, according to a paper published in the journal Current Biology.

Prior work had narrowed down the region on the X chromosome most likely to contain the relevant mutation. The scientists knew that females usually have just one copy of the mutation and in that case have tortoiseshell (partially orange) coloring, although in rare cases, a female cat will be orange if both X chromosomes have the mutation. Over the last five to ten years, there has been an explosion in genome resources (including complete sequenced genomes) for cats which greatly aided the team’s research, along with taking additional DNA samples from cats at spay and neuter clinics.

From an initial pool of 51 candidate variants, the scientists narrowed it down to three genes, only one of which was likely to play any role in gene regulation: Arhgap36. It wasn’t known to play any role in pigment cells in humans, mice, or non-orange cats. But orange cats are special; their mutation (sex-linked orange) turns on Arhgap36 expression in pigment cells (and only pigment cells), thereby interfering with the molecular pathway that controls coat color in other orange-shaded mammals. The scientists suggest that this is an example of how genes can acquire new functions, thereby enabling species to better adapt and evolve.

DOI: Current Biology, 2025. 10.1016/j.cub.2025.03.075 (About DOIs).

Not a Roman “massacre” after all

Two of the skeletons excavated by Mortimer Wheeler in the 1930s, dating from the 1st century AD. — Credit: Martin Smith

In 1936, archaeologists excavating the Iron Age hill fort Maiden Castle in the UK unearthed dozens of human skeletons, all showing signs of lethal injuries to the head and upper body—likely inflicted with weaponry. At the time, this was interpreted as evidence of a pitched battle between the Britons of the local Durotriges tribe and invading Romans. The Romans slaughtered the native inhabitants, thereby bringing a sudden violent end to the Iron Age. At least that’s the popular narrative that has prevailed ever since in countless popular articles, books, and documentaries.

But a paper published in the Oxford Journal of Archaeology calls that narrative into question. Archaeologists at Bournemouth University have re-analyzed those burials, incorporating radiocarbon dating into their efforts. They concluded that those individuals didn’t die in a single brutal battle. Rather, it was Britons killing other Britons over multiple generations between the first century BCE and the first century CE—most likely in periodic localized outbursts of violence in the lead-up to the Roman conquest of Britain. It’s possible there are still many human remains waiting to be discovered at the site, which could shed further light on what happened at Maiden Castle.

DOI: Oxford Journal of Archaeology, 2025. 10.1111/ojoa.12324 (About DOIs).

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A 2,000-year-old battle ended in fire, and a tree species never recovered

ancient china, ancient warfare, Archaeology, endangered species, han dynasty, save the trees, Science / 9u50fv / April 25, 2025

Then everything changed when the Fire Nation—sorry, the Han Empire—attacked.

Han rose to power in the wake of Qin’s collapse, after a short war with a rival dynasty called Chu, and spent the next century smugly referring to Nanyue as a vassal state and occasionally demanding tribute. At times, the rulers of Nanyue played along, but it all came to a head around 111 BCE, in the wake of an attempted coup and a series of assassinations. The Han Emperor sent an army of between 100,000 and 200,000 soldiers to invade Nanyue under a general named Lu Bode.

The troops marched across the countryside from five directions, converging outside Nanyue’s capital city of Panyou, which stood in the Pearl River Delta, near the modern city of Guangzhou. An enterprising company commander named Yang Pu got the bright idea to set the city on fire, and it ended badly.

“The fire not only destroyed the city but also ran out of control to the surrounding forests,” write Wang and colleagues. The cypress trees burned down to the waterline, leaving only their submerged stumps behind.

map of a coastal area showing elevation and the location of ancient forests — The brown dots mark the known sites of buried forests, and the orange diamonds mark those confirmed to be ancient. The two yellow diamonds are Wang and colleagues’ study sites. Credit: Wang et al. 2025

After war came fire and rice

At the time of the invasion, the land around Panyou was mostly swamp, forested with cypress trees. People had lived there for thousands of years, and had been growing rice for about 2,000 years. Bits of charcoal in the peat layers Wang and colleagues sampled reveal that they practiced slash-and-burn agriculture, but on a small scale, rotating their fields so the cypress forest could start to recover after a season or two.

The small burns are nothing like the forest fire Yang Pu unleashed, or the massive burning and reworking of the landscape that came after.

The stumps of the burned cypress trees slowly disappeared under several meters of peat, while above the buried ancient forest, life went on. Tigers, elephants, rhinos, and green peafowl no longer walked here. Instead, grains of pollen from the layers of clay above the peat reveal a sudden influx of plants from the grassy Poaceae family, which includes rice, wheat, and barley.

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Painted altar in Maya city of Tikal reveals aftermath of ancient coup

ancient people did stuff, Archaeology, indigenous americans, Maya, Mesoamerica, Pre-Columbian civilizations, Science, teotihuacan, tikal / Shannon Garcia / April 10, 2025

It’s always about colonialism

The altar marks the presence of an enclave of foreign elites from Teotihuacan.

This rendering shows what the altar might have looked like in its heyday. Credit: Heather Hurst

A family altar in the Maya city of Tikal offers a glimpse into events in an enclave of the city’s foreign overlords in the wake of a local coup.

Archaeologists recently unearthed the altar in a quarter of the Maya city of Tikal that had lain buried under dirt and rubble for about the last 1,500 years. The altar—and the wealthy household behind the courtyard it once adorned—stands just a few blocks from the center of Tikal, one of the most powerful cities of Maya civilization. But the altar and the courtyard around it aren’t even remotely Maya-looking; their architecture and decoration look like they belong 1,000 kilometers to the west in the city of Teotihuacan, in central Mexico.

The altar reveals the presence of powerful rulers from Teotihuacan who were there at a time when a coup ousted Tikal’s Maya rulers and replaced them with a Teotihuacan puppet government. It also reveals how hard those foreign rulers fell from favor when Teotihuacan’s power finally waned centuries later.

image of a rectangular limestone structure with recessed panels underground — Archaeologists don’t know what’s inside the altar, because they can’t excavate it without damaging the fragile painted panels. Credit: Ramirez et al. 2025

The painted altar

The altar stands in the courtyard of what was once a wealthy, influential person’s home in Tikal. At just over 1 meter tall, spanning nearly 2 meters in length and 1.3 meters wide, the altar is clearly the centerpiece of the limestone patio space.

It’s made of carved stone and earthen layers, covered with several smooth, fine plaster coatings. Murals adorn recessed panels on all four sides. In red, orange, yellow, and black, the paintings all depict the face of a person in an elaborate feathered headdress, but each is slightly different. All four versions of the face stare straight at the viewer through almond-shaped eyes. The figure wears the kind of facial piercings that would have marked a person of very high rank in Teotihuacan: a nose bar and spool-shaped ear jewelry (picture a fancy ancient version of modern earlobe plugs).

Proyecto Arqueológico del Sur de Tikal archaeologist Edwin Ramirez and his colleagues say the faces on the altar look uncannily like a deity who often shows up in artwork from central Mexico, in the area around Teotihuacan. Archaeologists have nicknamed this deity the Storm God, since they haven’t yet found any trace of its name. It’s a distinctly Teotihuacan-style piece of art, from the architecture of the altar to the style and color of the images and even the techniques used in painting them. Yet it sits in the heart of Tikal, a Maya city.

A pre-Columbian coup d’etat

Tikal was one of the biggest and most important cities of the Maya civilization. Founded in 850 BCE, it chugged along for centuries as a small backwater until its sudden rise to wealth and prominence around 100 CE. Lidar surveys of Guatemala have revealed Tikal’s links with other Maya cities, like Homul. And Tikal also traded with the city of Teotihuacan, more than 1,000 kilometers to the west, in what’s now Mexico.

“These powers of central Mexico reached into the Maya world because they saw it as a place of extraordinary wealth, of special feathers from tropical birds, jade, and chocolate,” says Brown University archaeologist Stephen Houston, a co-author of the recent study, in a statement. “As far as Teotihuacan was concerned, it was the land of milk and honey.”

Trade with Teotihuacan brought wealth to Tikal, but the Maya city seems to have attracted too much attention from its more powerful neighbor. A carved stone unearthed in Tikal in the 1960s describes how Teotihuacan swooped in around 378 CE to oust Tikal’s king and replace him with a puppet ruler. Spanish-language sources call this coup d’etat the Entrada.

The stone is carved in the style of Teotihuacan, but it’s also covered with Maya hieroglyphs, which tell the tale of the conquest. After the Entrada, there are traces of Teotihuacan’s presence all over Tikal, from royal burials in a necropolis to distinctly Mexican architecture mixed with Maya elements in a complex of residential and ceremonial buildings near the heart of the city.

And the newly unearthed altar seems to have been built shortly after the Entrada, based on radiocarbon dates from nearby graves in the courtyard and from material used to ritually bury the altar after its abandonment (more on that below).

Ramirez and his colleagues write that the altar is “likely evidence of the direct presence of Teotihuacan at Tikal as part of a foreign enclave that coincided with the historic Entrada.”

orthographic map of Tikal — This map shows the courtyard in relation to other major structures in Tikal. Credit: T.G. Garrison and H. Hurst

A wealthy household’s ritual courtyard

The buildings surrounding the courtyard would have been a residential compound for wealthy elites in the city; it’s not far from the city’s center with its temples and huge public plazas. Residents had used the courtyard as a private family ceremonial space for decades or even a couple of centuries before its owners installed the altar. And Ramirez and his colleagues say it’s no coincidence that archaeologists have found many such courtyards in Teotihuacan, which people also used as a space for household ceremonies like burials and offerings to the gods.

“What the altar confirms is that wealthy leaders from Teotihuacan came to Tikal and created replicas of ritual facilities that would have existed in their home city. It shows Teotihuacan left a heavy imprint there,” says Houston.

And in the Maya world, as in the world of Teotihuacan, ceremonial spaces usually come with skeletons included.

Ramirez and his colleagues unearthed the grave of an adult buried beneath the patio, in a tomb with limestone walls and a stucco floor. Nearby, a child had been buried in a seated position—something rare in Tikal but very common in Teotihuacan. The child’s burial radiocarbon-dated to decades before the Entrada, between 205 and 350 CE. It looks like someone buried both of these people beneath the floor of the courtyard of their residential compound not long after they moved in; it’s a good bet that they were members of the family who once lived here, but archaeologists don’t know for sure. These kinds of burials would have been exactly the sort of household ritual the courtyard was meant for.

Teotihuacan’s enclave in Maya Tikal

Sometime later—between 380 and 540 CE, based on radiocarbon dating—the people living in the compound buried the courtyard beneath a layer of dirt and rubble, laid a new floor over it, and essentially started over. This is when Ramirez and his colleagues say someone built and painted the altar.

It’s also when someone buried three babies in the courtyard, each near a corner of the altar (the fourth corner has a jar that probably once contained an offering, but no bones). Each burial required breaking the stone floor, placing the tiny remains underneath, and then filling in the hole with crushed limestone. That’s not the way most people in Tikal would have buried an infant, but it’s exactly how archaeologists have found several buried in very similar courtyards in faraway Teotihuacan.

In other words, the people who lived in this compound and used this courtyard and painted altar were probably from Teotihuacan or raised in a Teotihuacan enclave in the southern sector of Tikal. The compound is practically in the shadow of a replica of Teotihuacan’s Feathered Serpent Pyramid and its walled plaza, where archaeologists unearthed Teotihuacan-style incense burners made from local materials.

sketch of a rectangular altar with painted sides — This rendering shows what the altar might have looked like in its heyday. Credit: Heather Hurst

The end of an era

Sometime between 550 CE and 654 CE, based on radiocarbon dating, the foreign enclave in Tikal closed up shop. That’s around the time distant Teotihuacan’s power was starting to collapse. But it wasn’t enough to just leave; important buildings had to be ritually “killed” and buried. That meant burning the area around the altar, but it also meant that people buried the altar, the courtyard, the compound, and most of southern Tikal’s Teotihuacan enclave beneath several meters of dirt and rubble.

Whoever did the burying went to the trouble of making the whole thing look like a natural hill. Ramirez and his colleagues say that’s unusual, because typically once a building had been ritually killed and abandoned, something new would be built atop the remains.

“The Maya regularly buried buildings and rebuilt on top of them,” Brown University archaeologist Andrew Scherer, a co-author of the recent study, said in a statement. “But here, they buried the altar and surrounding buildings and just left them, even though this would have been prime real estate centuries later. They treated it almost like a memorial or a radioactive zone. It probably spoke to the complicated feelings they had about Teotihuacan.”

Antiquity, 2017. DOI: 10.15184/aqy.2025.3 (About DOIs).

Kiona is a freelance science journalist and resident archaeology nerd at Ars Technica.

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Research Roundup: 7 cool science stories we almost missed

Archaeology, Physics, Science / Mike M. / February 2, 2025

Peruvian mummy tattoos, the wobbly physics of spears and darts, quantum “cat states,” and more.

Lasers revealed tattoos on the hand of a 1200-year-old Peruvian mummy. Credit: Michael Pittman and Thomas G Kaye

It’s a regrettable reality that there is never time to cover all the interesting scientific stories each month. In the past, we’ve featured year-end roundups of cool science stories we missed. This year, we’re experimenting with a monthly collection. January’s list includes papers on using lasers to reveal Peruvian mummy tattoos; the physics of wobbly spears and darts; how a black hole changes over time; and quantum “cat states” for error correction in quantum computers, among other fascinating research.

Tracking changes in a black hole over time

Left: EHT images of M87from the 2018 and 2017 observation campaigns. Middle: Example images from a general relativistic magnetohydrodynamic (GRMHD) simulation at two different times. Right: Same simulation snapshots, blurred to match the EHT’s observational resolution. Credit: EHT collaboration

In 2019, the Event Horizon Telescope announced the first direct image ever taken of a black hole at the center of an elliptical galaxy, Messier 87 (M87), located in the constellation of Virgo some 55 million light-years away. Astronomers have now combined earlier observational data to learn more about the turbulent dynamics of plasma near M87*’s event horizon over time, according to a paper published in the journal Astronomy and Astrophysics.

Co-author Luciano Rezzolla of Goethe University Frankfurt in Germany likened the new analysis to comparing two photographs of Mount Everest, one year apart. While the mountain’s basic structure is unlikely to change much in that time, one could observe changes in clouds near the peak and deduce from that properties like wind direction. For instance, in the case of M87*, the new analysis confirmed the presence of a luminous ring that is brightest at the bottom, which in turn confirmed that the rotational axis points away from Earth. “More of these observations will be made in the coming years and with increasing precision, with the ultimate goal of producing a movie of what happens near M87*,” said Rezolla.

Astronomy and Astrophysics, 2025. DOI: 10.1051/0004-6361/202451296 (About DOIs).

Lasers reveal Peruvian mummy tattoos

A tattooed forearm of a Chancay mummy. Credit: Michael Pittman and Thomas G Kaye

Humans across the globe have been getting tattoos for more than 5,000 years, judging by traces found on mummified remains from Europe to Asia and South America. But it can be challenging to decipher details of those tattoos, given how much the ink tends to “bleed” over time, along with the usual bodily decay. Infrared imaging can help, but in an innovative twist, scientists decided to use lasers that make skin glow ever so faintly, revealing many fine hidden details of tattoos found on 1,200-year-old Peruvian mummies, according to a paper published in the Proceedings of the National Academy of Sciences.

It’s the first time the laser-stimulated fluorescence (LSF) technique has been used on mummified human remains. The skin’s fluorescence essentially backlights any tattoos, and after post-processing, the long-exposure photographs showed white skin behind black outlines of the tattoo art—images so detailed it’s possible to measure density differences in the ink and eliminate any bleed effects. The authors determined that the tattoos on four mummies—geometric patterns with triangles and diamonds—were made with carbon-based black ink skillfully applied with a pointed object finer than a standard modern tattoo needle, possibly a cactus needle or sharpened bone.

PNAS, 2025. DOI: 10.1073/pnas.2421517122 (About DOIs).

Sforza Castle’s hidden passages

Ground-penetrating radar reveals new secrets under Milan's Sforza Castle — Ground-penetrating radar reveals new secrets under Milan’s Sforza Castle Credit: Politecnico di Milano

Among the many glories of Milan is the 15th-century Sforza Castle, built by Francesco Sforza on the remnants of an earlier fortification as his primary residence. Legends about the castle abound, most notably the existence of secret underground chambers and passages. For instance, Ludovico il Moro, Duke of Milan from 1494–1499, was so heartbroken over the loss of his wife in childbirth that he used an underground passageway to visit her tomb in the Basilica of Santa Maria delle Grazie—a passageway that appears in the drawings of Leonardo da Vinci, who was employed at the court for a time.

Those underground cavities and passages are now confirmed, thanks to a geophysical survey using ground-penetrating radar and laser scanning, performed as part of a PhD thesis. Various underground cavities and buried passageways were found within the castle’s outer walls, including Ludovico’s passageway and what have may have been secret military passages. Those involved in the project plan to create a “digital twin” of Sforza Castle based on the data collected, one that incorporates both its current appearance and its past. Perhaps it will also be possible to integrate that data with augmented reality to provide an immersive digital experience.

Physics of wobbly spears and darts

Image sequence of a 100-mm long projectile during a typical ejection in experiments. — Image sequence of a 100-mm-long projectile during a typical ejection in experiments. Credit: G. Giombini et al., 2025

Among the things that make humans unique among primates is our ability to throw various objects with speed and precision (with some practice)—spears or darts, for example. That’s because the human shoulder is anatomically conducive to storing and releasing the necessary elastic energy, a quality that has been mimicked in robotics to improve motor efficiency. According to the authors of a paper published in the journal Physical Review E, the use of soft elastic projectiles can improve the efficiency of throws, particularly those whose tips are weighted with a mass like a spearhead.

Guillaume Giombini of the Université Côte d’Azur in Nice, France, and co-authors wanted to explore this “superpropulsion” effect more deeply, using a combination of experimental data, numerical simulation, and theoretical analysis. The projectiles they used in their experiments were inspired by archery bows and consisted of two flat steel cantilevers connected by a string, essentially serving as springs to give the projectile the necessary elasticity. They placed a flat piece of rigid plastic in the middle of the string as a platform. Some of the projectiles were tested alone, while others were weighted with end masses. A fork held each projectile in place before launch, and the scientists measured speed and deformation during flight. They found that the wobble produced by the weighted tip projectiles yielded a kinetic energy gain of 160 percent over more rigid, unweighted projectiles.

Physical Review E, 2025. DOI: 10.1103/PhysRevE.00.005500 (About DOIs).

Quantum “cat states” for error detection

Left to right: UNSW researchers Benjamin Wilhelm, Xi Yu, Andrea Morello, and Danielle Holmes, all seated and each holding a cat on their lap — Left to right: UNSW researchers Benjamin Wilhelm, Xi Yu, Andrea Morello, and Danielle Holmes. Credit: UNSW Sydney/CC BY-NC

The Schrödinger’s cat paradox in physics is an excellent metaphor for the superposition of quantum states in atoms. Over the last 20 years, physicists have managed to build various versions of Schrödinger’s cat in the laboratory whereby two or more particles manage to be in two different states at the same time—so-called “cat states,” such as six atoms in simultaneous “spin up” and “spin down” states, rather like spinning clockwise and counterclockwise at the same time. Such states are fragile, however, and quickly decohere. Physicists at the University of New South Wales came up with a fresh twist on a cat-state that is more robust, according to a paper published in the journal Nature Physics.

They used an antimony atom embedded within a silicon quantum chip. The atom is quite heavy and has a large nuclear spin that can go in eight directions rather than just two (spin up and spin down). This could help enormously with quantum error correction, one of the biggest obstacles in quantum computing, because there is more room for error in the binary code. “As the proverb goes, a cat has nine lives,” said co-author Xi Yu of UNSW. “One little scratch is not enough to kill it. Our metaphorical ‘cat’ has seven lives: it would take seven consecutive errors to turn the ‘0’ into a ‘1.’” And embedding the atom in a silicon chip makes it scalable.

Nature Physics, 2025. DOI: 10.1038/s41567-024-02745-0 (About DOIs).

New twist on chain mail armor

how polycatenated architected materials look in their fluid or granular state, conforming to the shape of the vessel in which it is held. — Credit: Wenjie Zhou

Scientists have developed a new material that is like “chain mail on steroids,” capable of responding as both a fluid or a solid, depending on the kind of stress applied, according to a paper published in the journal Science. That makes it ideal for manufacturing helmets or other protective gear, as well as biomedical devices and robotics components. The technical term is polycatenated architected materials (PAMs). Much like how chain mail is built from small metal rings linked together into a mesh, PAMs are composed of various interlocking shapes that can form a wide range of different 3D patterns.

The authors were partly inspired by the lattice structure of crystals; they just replaced fixed particles with rings or cage-like shapes made out of different materials—such as acrylic polymers, nylon, or metals—to make small 3D-printed structures small enough to fit in the palm of one’s hand. They then subjected these materials to various stressors in the laboratory: compression, a lateral shearing force, and twisting. Some of the materials felt like hard solids, others were squishier, but they all exhibited the same kind of telltale transition, behaving more like a fluid or a solid depending on the stressor applied. PAMs at the microscale can also expand or contract in response to electrical charges. This makes them a useful hybrid material, spanning the gap between granular materials and elastic deformable ones.

W. Zhou et al., Science, 2025. DOI: 10.1126/science.adr9713 (About DOIs).

Kitty robot mimics headbutts

Any cat lover will tell you that cats show humans affection by rubbing their heads against the body (usually shins or hands). It’s called “bunting,” often accompanied by purring, and it’s one of the factors that make companion animal therapy so effective, per the authors of a paper published in ACM Transactions on Human-Robot Interactions. That’s why they built a small robot designed to mimic bunting behavior, conducting various experiments to assess whether human participants found their interactions with the kitty-bot therapeutic. The robot prototypes were small enough to fit on a human lap, featuring a 3D-printed frame and a head covered with furry polyester fabric.

The neck needed to be flexible to mimic the bunting behavior, so the authors incorporated a mechanism that could adjust the stiffness of the neck via wire tension. They then tested various prototypes with university students, setting the neck stiffness to low, high, and variable. The students said they felt less tense after interacting with the robots. There was no significant difference between the settings, although participants slightly preferred the variable setting. We know what you’re thinking: Why not just get an actual cat or visit your local cat cafe? The authors note that many people are allergic to cats, and there is also a risk of bites, scratches, or disease transmission—hence the interest in developing animal-like robots for therapeutic applications.

ACM Transactions on Human-Robot Interactions, 2025. DOI: 10.1145/3700600 (About DOIs).

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A telltale toilet reveals “lost” site shown in Bayeux Tapestry

Archaeology, Science / 9u50fv / January 28, 2025

Seats of power

The Bayeux Tapestry, showing King Harold riding to Bosham, where he attends church and feasts in a hall, before departing for France. The Society of Antiquaries of London

According to Creighton and his co-authors, there has been quite a lot of research on castles, which dominated aristocratic sites in England after the Norman Conquest. That event “persists as a deep schism that continues to be seen as the watershed moment after which elites finally tapped into the European mainstream of castle construction,” they wrote. The study of residences (or “lordly enclaves”) has been more peripheral, yet the authors argue that up until 1066, aristocrats and rulers like King Harold invested heavily in residences, often co-located with churches and chapels.

The “Where Power Lies” project employed a wide range of research methodology—including perusing old maps and records, a re-analysis of past excavations, geophysics, ground-penetrating radar (GPR), and photogrammatic modeling—to define the signatures of such enclaves and map them into a single geographic information database (GIS). The project has identified seven such “lordly centers,” two of which are discussed in the current paper: an early medieval enclosure at Hornby in North Yorkshire and Bosham in West Sussex.

It has long been suspected that one particular manor house in Bosham (now a private residence) stands on the site of what was once King Harold’s residence. Per the authors, the original residence was clearly connected with Holy Trinity Church just to the south, parts of which date back to the 11th century, as evidenced by the posthole remains of what was once a bridge or causeway. More evidence can be found in a structure known as the “garden ruin,” little of which survives above ground—and even that was heavily overgrown. GPR data showed buried features that would have been the eastern wall of King Harold’s lordly enclave.

The biggest clue was the discovery in 2006 of a latrine within the remains of a large timber building. Its significance was not recognized at the time, but archaeologists have since determined that high-status homes began integrating latrines in the 10th century, so the structure was most likely part of King Harold’s residence. Co-author Duncan Wright of Newcastle University believes this “Anglo-Saxon en suite,” along with all the other evidence, proves “beyond all reasonable doubt that we have here the location of Harold Godwinson’s private power center, the one famously depicted on the Bayeux Tapestry.”

DOI: The Antiquaries Journal, 2025. 10.1017/S0003581524000350 (About DOIs).

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Skull long thought to be Cleopatra’s sister’s was actually a young boy

ancient DNA, ancient egypt, anthropology, Archaeology, cleopatra, forensic archaeology, Science / Mike M. / January 13, 2025

Scientists have demonstrated that an ancient human skull excavated from a tomb at Ephesos was not that of Arsinoë IV, half-sister to Cleopatra VII. Rather, it’s the skull of a young male between the ages of 11 and 14 from Italy or Sardinia, who may have suffered from one or more developmental disorders, according to a new paper published in the journal Scientific Reports. Arsinoë IV’s remains are thus still missing.

Arsinoë IV led quite an adventurous short life. She was either the third or fourth daughter of Ptolemy XII, who left the throne to Cleopatra and his son, Ptolemy XIII, to rule together. Ptolemy XIII didn’t care for this decision and dethroned Cleopatra in a civil war—until Julius Caesar intervened to enforce their father’s original plan of co-rulership. As for Arsinoë, Caesar returned Cyprus to Egyptian rule and named her and her youngest brother (Ptolemy XIV) co-rulers. This time, it was Arsinoë who rebelled, taking command of the Egyptian army and declaring herself queen.

She was fairly successful at first in battling the Romans, conducting a siege against Alexandria and Cleopatra, until her disillusioned officers decided they’d had enough and secretly negotiated with Caesar to turn her over to him. Caesar agreed, and after a bit of public humiliation, he granted Arsinoë sanctuary in the temple of Artemis in Ephesus. She lived in relative peace for a few years, until Cleopatra and Mark Antony ordered her execution on the steps of the temple—a scandalous violation of the temple as a place of sanctuary. Historians disagree about Arsinoë’s age when she died: Estimates range from 22 to 27.

Archaeologists have been excavating the ancient city of Ephesus for more than a century. The Octagon was uncovered in 1904, and the burial chamber was opened in 1929. That’s where Joseph Keil found a skeleton in a sarcophagus filled with water, but for some reason, Keil only removed the cranium from the tomb before sealing it back up. He took the skull with him to Germany and declared it belonged to a likely female around 20 years old, although he provided no hard data to support that conclusion.

It was Hilke Thur of the Austrian Academy of Sciences who first speculated that the skull may have belonged to Arsinoë IV, despite the lack of an inscription (or even any grave goods) on the tomb where it was found. Old notes and photographs, as well as craniometry, served as the only evidence. The skull accompanied Keil to his new position at the University of Vienna, and there was one 1953 paper reporting on craniometric measurements, but after that, the skull languished in relative obscurity. Archaeologists at the University of Graz rediscovered the skull in Vienna in 2022. The rest of the skeleton remained buried until the chamber was reopened and explored further in the 1980s and 1990s, but it was no longer in the sarcophagus.

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