Science

Centuries before the Inca, Peru’s wealthy imported parrots from afar

ancient people did stuff, Archaeology, inca, indigenous americans, indigenous south america, parrots, Pre-Columbian civilizations, Science, wari / Tim Belzer / March 12, 2026

The Inca Empire’s system of roads were built on centuries-old trade routes.

This large, elaborate Ychsma funerary bundle features a wooden mask painted with cinnabar and adorned with a parrot-feather headdress. Credit: Olah et al. 2026

Centuries before the rise of the Inca Empire, a much smaller kingdom on the central coast of Peru already had a sophisticated trade network—one it used to import live parrots across the Andes from the Amazon rainforest.

Australian National University conservation geneticist George Olah and his colleagues recently studied feathers from a headdress in a Ychsman noble’s tomb, dating to 1100–1400 CE (the centuries before the rise of the Inca Empire). DNA and chemical isotopes reveal that the parrots the feathers came from (still bright blue, yellow, and green after all these centuries) were born in the wild on the far side of the Andes but kept in captivity somewhere on the Peruvian coast. To pull off importing live parrots from hundreds of miles away across the steep, towering Andes, the Ychsma (who the Inca annexed around 1470) must have had a far-reaching trade network that spanned at least half a continent.

And they must have really liked birds.

Long-distance trade before the Inca roads

Olah and his colleagues carefully selected fragments of individual barbs (the thin keratin strands that make up the body of a feather) from 25 feathers sewn onto funerary headdresses found at the pre-Inca city of Pachacamac, located on the dry coast of present-day Peru, just south of Lima. From each fragment, researchers sequenced mitochondrial DNA and measured the ratios of certain nitrogen and carbon isotopes, which can reveal information about a creature’s diet.

The results suggest the parrots were born in the wild but spent at least a year in captivity eating local maize. That means they must have been captured hundreds of kilometers away, because parrots don’t tend to flock to the desert on their own.

The Ychsma kingdom grew out of a fragment of the old Wari Empire (known for its hallucinogenic beer, its canal system, and for breaking up around 1100 CE after a solid 500-year run). Centered at Pachacamac, the Ychsma built pyramids and irrigated their arid river valleys to grow crops. And like most of the cultures that lived in the Andes highlands and along the coasts of modern-day Peru and Chile, they really had a thing for parrot feathers.

Parrots’ colorful blue, green, and red feathers were the status symbol, “essential for communicating status, power, and cosmology,” as Olah and his colleagues put it. In the Andes highlands, the Wari—and later the Inca—imported bright-feathered rainforest birds in the millions over several centuries. On the coasts, the Moche and Nasca cultures did much the same.

Parrot feathers feature in headdresses and in tunics made from thousands of feathers sewn onto cotton cloth. The birds themselves show up in tombs and temples as mummified offerings, and they were sculpted and painted onto centuries’ worth of pottery.

The parrot feathers on a handful of funerary headdresses from one of the only unlooted, intact tombs left at Pachacamac recently indicated that the Ychsma were linked to a trade network that once connected huge swaths of two continents across hundreds of kilometers.

Based on parrots and their feathers alone, archaeologists knew there must have been connections that reached from the Amazon basin west to the coastal deserts of Chile and Peru and north to Mexico and the southwestern United States. But the details of that trade—including how live parrots ended up crossing one of the world’s most daunting mountain ranges—were unclear for the centuries before the rise of the Inca Empire and its imperial road networks.

Until recently, archaeologists and historians assumed that the period between the breakup of the Wari Empire and the rise of the Inca was mostly a time when smaller kingdoms and confederations, like Ychsma and its neighbors, squabbled with each other and had influence that didn’t reach much beyond their own region. But based on parrot feathers, these between-empires Andean cultures actually had complex, thriving, and very sophisticated trade relationships without needing to have a system imposed by a central imperial government.

photo of roughly a dozen red and blue macaws on a cliffside — Macaws hang out in the Peruvian Amazon. Credit: Balazs Tisza

Born in the rainforest, raised in the desert

The headdress feathers came from four parrot species: scarlet macaws, red-and-green macaws, blue-and-yellow macaws, and mealy amazons. (The last are cute little green dudes that really deserve a nicer name; “mealy” is apparently a reference to the dusty “powder down,” grains of keratin formed by the disintegrating tips of their down feathers.) All of them live in lowland tropical forests and palm swamps in the Amazon Basin; Peru’s coastal deserts are practically the opposite of their usual wet, lush habitat.

Some pre-colonization cultures bred their own parrots, including at Chaco Canyon in New Mexico and at a huge pueblo complex called Paquimé in Mexico’s Chihuahua Desert. You can tell from the Paquimé parrots’ DNA that they came from a small, slightly inbred population, probably one descended from a breeding colony imported together on a single trip.

But at Pachacamac, the parrots’ DNA looked like it had come from a larger, more genetically diverse population. In fact, it looked a lot like the level of genetic diversity found in modern wild parrots. In other words, the Pachacamac headdresses used feathers from parrots born and bred in the wild.

But they didn’t spend their entire lives there. “The birds were not living in the rainforest when these feathers grew,” wrote Olah and his colleagues. A high proportion of carbon-13 in the feather barbs meant that while they were growing, the birds had been eating a diet rich in domestic grains like maize. Meanwhile, nitrogen-15 in the feathers suggested that ocean food chains had played a role, perhaps through seabird guano being used to fertilize the maize.

Most parrot species molt and regrow feathers about once a year, though it can vary by a few months, so these birds must have spent at least six to 18 months in Ychsma territory before being plucked for someone’s funerary headdress. And that means that someone in the Amazon was trading with the Yschma, handing over not just bundles of feathers but live parrots.

Archaeologists found similar evidence in mummified parrots, buried as ritual offerings, at the trading city of Pica, roughly 1,000 kilometers south of Pachacamac in Chile’s Atacama Desert. Pica thrived from around 900 CE to around 1400 CE, the same pre-Inca period as Pachacamac.

photo of part of a headdress with blue and yellow feathers attached — These feathers detached from the headdress they were originally part of. Credit: Izumi Shimada

Very intrepid delivery service

Getting a bunch of parrots across the Andes Mountains alive and in reasonably good condition is not an easy task—certainly not one your faithful correspondent would volunteer for. The authors used least-cost modeling, a method that maps the most efficient or lowest-energy path across a landscape, to create a likely map of those ancient parrot-trading routes, starting from ten sites in the Amazon and ending at Pachacamac.

If river travel were an option, one potential route cuts straight east across the Andes to Pachacamac. It lines up well with historical accounts describing how the Arawak-speaking Yanesha people traveled along very similar paths to trade in the coastal valleys of central Peru.

Another route crosses the Andes further north, ending up around Chimú, home of the Kingdom of Chimor, the largest of the post-Wari, pre-Inca kingdoms. From that area of northern Peru, it then follows the coastline southward to Pachacamac. Archaeological evidence already shows that Chimor traded with the Chachapoyas culture, located in the cloud forests on the eastern slopes of the Andes. And their “people were known for their bird-catching skills,” according to Olah and his colleagues.

Since both of these routes are supported by archaeological and historical evidence, it’s entirely possible that the Ychsma were getting their parrots through both networks. Presumably, they must have been sending back valuable goods in return.

“Transporting goods such a great distance by land and/or sea raises the questions of the high costs involved,” wrote Olah and his colleagues. But for people in both the Andes highlands and along the arid coasts, the parrots and their colorful, exotic feathers were presumably worth whatever it cost to get them. In other words, the most affluent and powerful people among the Ychsma and their neighbors were willing to make it worth the Amazon traders’ while to procure and deliver the birds.

(Unfortunately, that’s still true of unscrupulous pet breeders and collectors today.)

“This study also provided a deep historical context for a human fascination with colorful parrots that today drives a destructive illegal trade threatening their very survival,” Olah and his colleagues wrote.

Nature Communications, 2026. DOI: 10.1038/s41467-026-69167-9 (About DOIs).

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

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Ig Nobels ceremony moves to Europe over security concerns

culture, Ig Nobels, Science / Mike M. / March 10, 2026

Traditionally, the awards ceremony and related Ig Nobel events have taken place in Boston at Harvard University, Massachusetts Institute of Technology, and Boston University. However, four of last year’s 10 winners opted to skip the ceremony rather than travel to the US, and the situation has not improved.

Nor is it just the Ig Nobels being affected by the hostile US environment for international travel. Many international gaming developers are choosing to skip this year’s weeklong Game Developers Conference in San Francisco, citing similar concerns. “I honestly don’t know anyone who is not from the US who is planning on going to the next GDC,” Godot Foundation Executive Director Emilio Coppola, who’s based in Spain, told Ars. “We never felt super safe, but now we are not willing to risk it.”

So this year, the Ig Nobel organizers are joining forces with the ETH Domain and the University of Zurich for hosting duties. “Switzerland has nurtured many unexpected good things—Albert Einstein’s physics, the world economy, and the cuckoo clock leap to mind—and is again helping the world appreciate improbable people and ideas,” Abraham said.

The Ig Nobels will not be returning to the US any time soon. Instead, the plan is for Zurich to host every second year; every odd-numbered year, the ceremony will be hosted by a different European city. Abraham likened the arrangement to the Eurovision Song Contest.

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An unlikely set of clues helps reconstruct ancient Chinese disasters

ancient china, anthropogenic climate change, Archaeology, El Niño, extreme weather, Science, typhoons / Kris Guyer / March 9, 2026

Shang Dynasty oracle bones and modern weather models feature in the same study.

This diorama at Xinxiang City Museum, Henan Province shows what a Shang Dynasty village might have looked like. Credit: Gary Todd, CC0, via Wikimedia Commons

Warmer waters in the Pacific Ocean may have brought devastating floods to the cradle of ancient Chinese civilization, according to a recent study in which its authors link three wildly different lines of evidence to tell the story.

People in Shang Dynasty China, around 3,000 years ago, probably didn’t realize that the massive floods sweeping through their heartland were the product of typhoons battering the southern Chinese coast hundreds of kilometers away. They certainly couldn’t have seen that the sheer intensity of those typhoons was fueled by a sudden shift in temperature cycles over the Pacific Ocean thousands of kilometers to the south and east. But, with the benefit of 3,000 years of hindsight and scientific progress, Nanjing University meteorologist Ke Ding and colleagues recently managed to connect the dots. The results are like a handwritten warning from the Shang Dynasty about how to prepare for modern climate change.

Typhoons, oracle bones, and abandoned settlements

Around 3,000 years ago, two great civilizations were flourishing in central China. In the Yellow River Valley, the Shang Dynasty rose to prominence, producing the first Chinese writing and also sacrificing thousands of people in ceremonies at the capital, Yinxu. Meanwhile, on the Chengdu Plain in southwestern China, the Shanxingdui culture built a walled capital city and sculpted large bronze heads, gold foil masks, and tools of jade and ivory, which they buried in huge sacrificial pits.

Archaeological sites across central China reveal that at various points between 2,500 and 4,000 years ago, disasters rocked these thriving societies, decimating the population, forcing settlements to relocate, and causing major cultural shifts and political upheaval.

Both civilizations rebounded after these disruptions; it didn’t take long, in the archaeological scheme of things, for populations to swell and settlements to rebuild. But for a little while, life was clearly disrupted.

A few wildly different clues point to the cause—or at least, one of the causes—of this upheaval: modern weather simulations, archaeological sites hundreds of miles from the Chinese coast, coastal sediments in Japan and South Korea that record the intensity of ancient typhoons, and even Shang Dynasty divination texts. All three of these lines of evidence converged on the same dates, telling a single horrifying story.

Reconstructing ancient storm seasons

We have a pretty good idea of how the size and intensity of a storm determines what kind of footprint it leaves on coastal sediments. Researchers look for similar traces in ancient sediments and use them to reconstruct what tropical storm seasons were like in the past (the field is called paleotempestology, which is your faithful correspondent’s new favorite word).

Based on paleotempestology records not only in China, but also along the coasts of South Korea and southwestern Japan, typhoons moving west across the Pacific Ocean tended to be more intense during the storm seasons around 2,800 years ago. Typhoons that curved northward had more intense seasons around 3,800 years ago and again around 3,300 years ago.

Those bouts of more intense typhoons may be related to something that happened off the coast of Peru around 3,000 years ago, when El Niño events suddenly got more frequent, more extreme, and longer-lasting. Paleoclimate researchers know this because around this time, shellfish species that live in cool water (but can’t take the heat) all but disappear from the Peruvian archaeological record, replaced by more heat-tolerant species. Around the same time, people living along the coast gave up building huge monumental temples, and villages shrank. You’re going to want to keep those dates in mind, because…

Ding and colleagues charted radiocarbon dates from sites across China’s Central Plains and Chengdu Plain, hoping to pinpoint changes in population and potential signs of a society in crisis. They noticed that the number of sites on the Central Plain, home to the Shang Dynasty, decreased sharply around 3,800 years ago and again about 3,300 years ago; at the sites that weren’t abandoned, changes suggested smaller populations overall. On the Chengdu Plain, something similar happened around 2,800 years ago. Villages, towns, and cities shifted toward higher ground; layers of mud left behind by flooding hint at the reason.

map of the Pacific ocean and China showing typhoon paths — This map shows the tracks of typhoons during the 1995 storm season; note that some plow straight west, while others veer northward. Credit: By Nilfanion – Created using Wikipedia:WikiProject Tropical cyclones/Tracks. The background image is from NASA [1]. The tracking data is from the Joint Typhoon Warning Center’s best track database, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2505757

How does a typhoon in the Pacific flood inland China?

Seeing how well those dates lined up with when coastal sediments suggest more intense typhoons had been churning through the Pacific, Ding and colleagues ran some computer simulations using an LLM-based program called Pango-weather. The goal was to figure out how a typhoon on the coast could bring torrential rains and flooding to communities hundreds of miles inland. The answer wasn’t that the typhoon swept across the entire country; often, the typhoons in question never even made landfall. But they didn’t have to make landfall to stir up easterly winds that carried more water vapor across hundreds of miles to the plains.

Both the Shang Dynasty and Shu civilizations set up their capitals on plains just to the east of large mountain ranges. Normally, that works out very well for farmers, because the mountains force eastbound air upward, where it cools; water vapor condenses and rain falls. But settlements on the windward side of mountain ranges are also vulnerable to extreme rainfall events—like the ones caused by typhoons messing with the region’s airflow patterns.

Ding and colleagues’ results suggest that an increase in the average intensity of typhoons (which means that the researchers boosted the storms’ starting wind speed from about 54 kilometers per hour to about 126 kilometers per hour) caused more moisture to gather over regions like the Chengdu Plain and the Central Plains. Specifically, the Chengdu Plain was more impacted by typhoons moving west, while the Central Plains caught more flooding from typhoons that followed northward tracks. The effects were on the order of an extra 51 millimeters of rain a day in the Central Plains and extra 24 millimeters a day on the Chengdu Plain.

Consulting the oracle bones

The people of the Shang Dynasty and the Shu civilization probably didn’t know that large-scale weather systems, or even larger-scale climate shifts, were to blame for their woes, but they were definitely aware that they were living through periods in which serious floods were more likely. Writings on more than 55,000 pieces of burned bone from the late Shang Dynasty (2,996–3,200 years ago) reveal that Shang royals and nobles were very worried about heavy rains and floods during the period—worried enough to ask oracles to try to predict them.

Shang Dynasty rulers took their most pressing questions to oracles, who would throw oxen shoulder blades (scapulae) or the bony undersides of turtle shells (plastrons) onto a fire, then interpret the pattern of cracks in the burned bone. Fortunately for modern historians, those oracles also inscribed both the question and the answer into the bone itself, producing some of China’s first systematic writing.

Ding and colleagues counted the references to “upcoming rain” and “upcoming heavy rain” in the texts and found that Shang nobility asked their diviners about downpours much more often during the exact time periods when sediments suggest more intense typhoons and archaeological evidence suggest major social and political upheaval. And you don’t tend to keep asking if there’s going to be a big flood unless you have good reason to think that there might be.

photo of an ox scapula inscripted with early Chines characters in columns — 3,000 years ago, a Shang Dynasty oracle tossed this ox scapula into a fire, looking for hints about the future in the way the burned bone cracked. Credit: By Gary Lee Todd 2011-09-01 12: 34: 54 https://www.flickr.com/photos/101561334@N08/9830601816/, CC0, https://commons.wikimedia.org/w/index.php?curid=96430584

When it rains, it pours

Of course, it’s not possible to say that these periods of unrest and struggle in ancient China happened entirely thanks to more intense typhoons, but the cycle of worsening storm seasons probably played a role. And in between floods, the lack of water may have been another major factor.

Paleoclimate records in ancient sediment reveal that even as typhoons were getting more intense, central China was baking under a drought—also thanks to the same cycle that drives El Niño today (recent studies suggest that El Niño years lead to severe droughts in central China and more intense typhoons in the Pacific). And the oracle bones reflect Shang dynasty rulers’ concerns about drought, too: references to prayers for rain and plagues of locusts closely match the periods of El Niño conditions identified in previous studies. The Shang Dynasty was getting hit with a one-two punch of climate disasters: years of drought, punctuated by heavy rains and devastating floods.

“This pattern bears similarities to the climatic challenges faced by the Maya civilization,” wrote Ding and colleagues, “where prolonged El Niño-like conditions may reduce overall rainfall while intensified cyclone activity could increase extreme rainfall, ultimately contributing to social declines.”

Why it matters today

Those 3,000-year-old oracle bones hold a warning for modern China. The character for “disaster” in the oracle bone scripts is a set of squiggly horizontal lines that immediately calls to mind floodwaters, and floods are still one of the deadliest and costliest disasters that China faces. Not only are floodwaters destructive, but they can leave behind too much salt in the soil and can also lead to outbreaks of insects and other pests (for both people and crops).

The mechanics that connect typhoon intensity to flooding in inland China work the same way they did during the Shang Dynasty. Current climate models predict that typhoons could be 14 percent more intense, on average, by the end of this century, thanks to humans and our pollution habits.

But the message from the oracle bones isn’t about despair; it’s about planning. As Ding and colleagues put it: “This study urges better preparation against the disastrous impact of intensified typhoons, especially in inland areas where facilities to mitigate extreme rainfalls and floods are relatively inadequate.”

Science Advances, 2026 DOI: 10.1126/sciadv.eaeb1598 (About DOIs).

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

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Flexible feline spines shed light on “falling cat” problem

falling cats, Physics, Science / Rejus Almole / March 9, 2026

Why do falling cats always seem to land on their feet? Scientists have been arguing about the precise mechanism for a very long time—since at least 1700, in fact—conducting all manner of experiments to pin down what’s going on. The research continues, with a paper published in the journal The Anatomical Record reporting on new experiments to analyze the flexibility of feline spines.

We covered this topic in-depth in 2019, when University of North Carolina, Charlotte, physicist Greg Gbur published his book, Falling Felines and Fundamental Physics. For a long time, scientists believed that it would be impossible for a cat in free fall to turn over. That’s why French physiologist Etienne-Jules Marey’s 1894 high-speed photographs of a falling cat landing on its feet proved so shocking to Marey’s peers. But Gbur has emphasized that cats are living creatures, not idealized rigid bodies, so the motion is more complicated than one might think.

Over the centuries, scientists have offered four distinct hypotheses to explain the phenomenon. There is the original “tuck and turn” model, in which the cat pulls in one set of paws so it can rotate different sections of its body. Nineteenth-century physicist James Clerk Maxwell offered a “falling figure skater” explanation, whereby the cat tweaks its angular momentum by pulling in or extending its paws as needed. Then there is the “bend and twist,” in which the cat bends at the waist to counter-rotate the two segments of its body. Finally, there is the “propeller tail,” in which the cat can reverse its body’s rotation by rotating its tail in one direction like a propeller.

At the time, Gbur told Ars that, while all those different motions play a role, he thought that the bend-and-twist motion was the most important. “When one goes through the math, that seems to be the most fundamental aspect of how a cat turns over,” he said. “But there are all these little corrections on top of that: using the tail, or using the paws for additional leverage, also play a role.” This latest paper has Gbur rethinking that conclusion, according to his recent blog post, giving a bit more credence to the tuck-and-turn mechanism.

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Tiny, long-armed dinosaur leads to rethink of dinosaur miniaturization

Biology, dinosaurs, evolution, paleontology, Science / Tim Belzer / March 8, 2026

Small size seems to have come before a change in diet for a tiny dinosaur lineage.

Alvarezsaurids were mostly small-bodied theropods that paleontologists originally misinterpreted as early flightless birds, only to later recognize them as an ant-eating lineage of non-avian dinosaurs. For years, we suspected that Alvarezsaurids underwent a rare process of evolutionary miniaturization directly coupled to a diet of social insects like ants and termites. It was a tidy hypothesis: They got smaller to become more efficient at catching ants.

Now, a recently discovered fossil of one of the smallest alvarezsaurids ever found suggests that the evolution of miniature dinosaurs likely wasn’t as neat and linear as we thought. This new species, called Alnashetri cerropoliciensis, probably did not feed on ants at all. “It was a pursuit predator actively hunting insects and small mammals,” said Peter Makovicky, a paleontologist at the University of Minnesota.

The oddball

Alverezsaurids, found mostly in the Late Cretaceous rocks of Asia and South America, had short forelimbs tipped with a single oversized thumb claw built for digging. They also had minute teeth and sensory adaptations akin to those in modern nocturnal birds—everything necessary to work on termite mounds. “The explanation of their small body size has been tied to this specialization,” Makovicky explained.

The dinosaur he and his colleagues found, however, did not look like a specialized ant-eater.

The fossil of Alnashetri cerropoliciensis was unearthed from the Candeleros Formation at the Cerro Policía locality in Argentina’s Río Negro Province and is estimated to have lived roughly 90 million years ago. It currently stands as the most complete and smallest Alvarezsaurid skeleton found in South America.

While missing its skull roof, parts of its right arm, its lower right leg, and much of its tail, the skeleton preserves plenty of its crucial anatomy. Its bone tissue reveals that the alvarezsaurid was a subadult, likely approaching sexual maturity, as indicated by the presence of what appears to be medullary bone, a temporary tissue associated with egg-laying in modern birds. Despite being nearly fully grown, this dinosaur is estimated to have weighed a mere 700 grams.

The real surprise, though, came when researchers realized that Alnashetri wasn’t a highly specialized, late-stage Alvarezsauroid. Instead, despite living in the Late Cretaceous, it occupied an early-branching position among earlier, basal members of the clade.

This combination of tiny size and early-branching status fundamentally breaks our previous model of how these animals evolved. If the miniaturization of Alvarezsauroids was strictly tied to their lifestyle as stubby-armed insect-eaters, an early-diverging species like Alnashetri should have some transitional features on a steady, clade-wide march toward that extreme endpoint. But it didn’t look that way.

“It’s a very long-limbed animal, so it was probably fairly fast. My best analogy would be something like a roadrunner from the American West,” Makovicky said.

Arms and teeth

Late Alvarezsaurids had tiny, robust forelimbs that were less than half the length of their femurs. Alnashetri, though, sported comparatively long forelimbs that were 61 percent of the length of its entire hindlimb. While it had three-fingered hands with a robust first digit, a hallmark of its group, it still retained slender second and third digits, unlike its later cousins.

Other features that challenge the established evolutionary model of miniature dinosaurs are Alnashetri’s jaws and teeth. Its dentition features non-serrated teeth set into sockets, but importantly, these teeth are not extremely small, as they were in the late Alvarezsaurids like Shuvuuia or Jaculinykus. “This decoupled the evolution of small body size from anatomical specializations,” Makovicky explained.

The team concluded that extreme miniaturization in Alvarezsaurids did not necessarily co-evolve with either the evolution of smaller arms more suitable for digging or small teeth built for crushing ants and/or termites. Instead of a clade-wide trend where the entire lineage steadily shrank over time, a new evolutionary model that includes Alnashetri suggests that Alvarezsaurid body mass fluctuated repeatedly. Alnashetri, it turns out, achieved its 700-gram frame independently from the other, highly specialized alvarezsaurid species.

But Alnashetri didn’t just upend the understanding of how Alvarezsaurids evolved their tiny bodies. It also redrew the map of where they lived.

Museum tour

Before Makovicky’s study, it was a mystery why Alvarezsaurids were found almost exclusively in the late Cretaceous rocks of Asia and South America. The previous leading hypothesis suggested that the group must have dispersed back and forth between these two landmasses relatively late in the game. But placing Alnashetri, a remarkably basal member, into their evolutionary tree created a massive ghost lineage. The phylogenetic analysis linked geographically close South American species to much older, geologically distant Asian taxa like Bannykus and Xiyunykus, implying that the group must have diverged way back in the Jurassic period.

To explain this chronological and geographic gap, Makovicky and his colleagues started digging through historical museum collections to see if early Alvarezsaurids had been hiding there under different names. It turned out they had.

The team successfully reidentified a small, fragmentary theropod from the Upper Jurassic Morrison Formation in North America, as well as a Lower Cretaceous taxon from the Isle of Wight in Europe. These were early, diverging Alvarezsaurids, and they possessed distinct features such as specialized ball-and-socket joints in the neck vertebrae that are unique in the Alvarezsaurid clade. These museum reidentifications entirely changed the biogeographical story.

If Alvarezsaurids were roaming North America and Europe in the Jurassic and Early Cretaceous, they weren’t just performing a late-stage migration between Asia and South America. Instead, the new model proposed by Makovicky and his team reconstructs a widespread Pangaean distribution. Early Alvarezsaurids were likely present across the globe before the supercontinent Pangaea fully fractured.

The Late Cretaceous distributions we see in the fossil record today would therefore be the result of populations slowly becoming isolated as the continents drifted apart, combined with regional extinctions that wiped them out in places like North America and Europe. The populations in Asia and South America represent surviving pockets.

Still, Makovicky’s work produced far more questions than answers. If at least some Alvarezsaurids did not evolve their miniature bodies as an adaptation to eating ants, what made them so small?

Messy evolution

“We sort of falsified this nice narrative where Alvarezsaurid body size change was driven by ecology, but unfortunately, we don’t have anything good to replace it,” Makovicky acknowledged.

The classic story of Alvarezsaurids—a lineage steadily shrinking in lockstep as it committed to a life of termite-hunting, finally migrating across the Late Cretaceous globe—was neat and logical, but it’s apparently gone now. “That’s science. Sometimes you can falsify a hypothesis without necessarily finding a better one to support,” Makovicky added. But his team is already busy looking for evidence documenting the new, more complex and messier version of Alvarezsaurid evolutionary history. “We have a couple of angles we’re pursuing,” he said.

The first involves taking a closer look at Alnashetri’s anatomy using CT scans. The goal here is to treat Alnashetri as a starting point to understand the stepwise evolution of its ant-eating, specialized cousins. Most of this meticulous scanning is currently happening in Argentina. The second angle, though, seems way more thrilling. “By pure luck, we found another Alvarezsaur in the same general area,” Makovicky said.

The other Alvarezsaur is bigger than Alnashetri and has slightly shorter forelimbs. “It’s still being prepared, but I think it will sort of give us the next chapter in the story of how Alvarezsaurids evolved,” Makovicky explained. “It’s probably a few years out in the making.”

Makovicky’s work on Alnashetri is published in Nature: https://doi.org/10.1038/s41586-026-10194-3

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

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Hunting for elusive “ghost elephants”

culture, elephant conservation, elephants, National Geographic, pachyderms, Science, werner herzog / Mike M. / March 7, 2026

the elephant never forgets

Werner Herzog directed this evocative NatGeo documentary of an ornithologist’s quest to find a new species.

The first photo of a “ghost elephant” captured by a motion-controlled camera. Credit: Courtesy of The Wilderness Project Archive

Deep in the Angolan Highlands lurks a rumored new species of elephant. Conservationist and ornithologist Steve Boyes has been searching for this elusive herd for years and the story of his journey is the focus of Ghost Elephants, a haunting, evocative documentary directed by Werner Herzog. The film debuted at the Venice International Film Festival last summer and is now coming to National Geographic and Disney+.

It might seem unusual for an ornithologist to embark on a quest to find remote pachyderms, but for Boyes the connection is perfectly natural. He grew up in South Africa and wanted nothing more than to be an explorer, just like the people he read about every month in National Geographic magazine. “I grew up waiting for the magazine to arrive; I wanted the maps,” Boyes told Ars. “Those would become my garden, or the field beyond, or the river—wild places imagined and real.”

Boyes’ parents frequently took him and his brother out into the wild, including visits to Botswana and Tanzania. “We used to embed ourselves in baboon troops and walk with impalas,” said Boyes, and while his brother feared elephants, Boyes was walking with them from a young age. Ghost Elephants contains some gorgeous underwater footage of elephant feet plodding through the water, and elephants swimming on their sides, behavior that matches Boyes’ own experiences with the animals. Under the right circumstances, if they don’t feel threatened, elephants “will come and swim around you and with you and interact with you,” he said. “So elephants have always fascinated me.”

As an adult, Boyes conducted his PhD research on the Meyer’s parrot in the Okavango Delta, which has the single largest population of elephants in the world. They shared a symbiotic relationship of sorts with the parrots. “Every tree that the parrots were feeding on, the elephantss were feeding on,” he said. “The elephants were creating the nest cavities for the parrots by disturbing the trees.”

Boyes first met Herzog at a Beverly Hills restaurant through a mutual friend and the two ended up chatting at length, “about the meaning of life, where thoughts come from, personal experiences of loneliness, and the ghost elephants,” said Boyes. Herzog has said that after meeting Boyes, “An unexpected project that felt like the hunt for Moby Dick, the White Whale, came at me with urgency. Like many of my films, this is an exploration of dreams, of imagination—weighed against reality.”

Dreams weighed against reality

Dr. Steve Boyes stands in the rotunda of the Smithsonian Museum confronting the largest elephant ever killed Skellig Rock, Inc

When Herzog visited Boyes in Namibia, he fell in love with the region’s culture, mythology, and people, and his camera captures far more than just a scientific quest for elephants. We are treated to a ritual elephant dance—during which a tribal elder falls into a trance, so the spirit of the elephant can enter his body—and a history of the tribe’s ingenious use of poisoned arrows to hunt. Boyes is granted an audience with the local king, seeking his blessing for the expedition. At one point, the director becomes fascinated by a poisonous spider he films in the middle of the night, carrying dozens of equally poisonous babies on her back.

“Once he was locked in, there was no discussion with him around the story or anything outside of being interviewed or being actively in the experience,” said Boyes of Herzog’s creative process. It was direct and efficient, with Herzog usually capturing the footage he needed right away, seeing no need for additional coverage. The questions the director asked were unique as well. “The first question was, ‘What would a world without elephants be like? What do you dream of?’” recalled Boyes. “He took us into a mode of thought that was very different from just preparing for an expedition. I love him. He’s wonderful.”

Ghost Elephants opens in the rotunda of the Smithsonian National Museum of Natural History, which has housed the largest elephant mount in the world since 1959—affectionately dubbed Henry or “the Giant of Angola.” A Hungarian big game hunter named Josef J. Fénykövi shot and killed Henry in November 1955 with a dozen high-caliber bullets. Henry is the largest elephant ever recorded, over 13 feet tall and weighing about 11 tons, and there was the remains of an old iron slug from a flintlock rifle embedded in Henry’s left front leg. So Henry could have been 100 years old or more at the time he was killed.

Visiting Henry is the perfect starting point for the film, since Boyes suspected he might be related to the new species of ghost elephant in the Angolan highlands. Boyes had searched for these elephants using modern camera traps and other advanced technologies, to no avail. This time, he recruited three KhoiSan master trackers—Xui, Xui Dawid, and Kobus—who left their southern village to accompany Boyes’ team into the Angolan Highlands.

It was not an easy trip, given the remoteness of the “Source of Life,” i.e., the Angolan Highlands Water Tower where the elephants live—so named because it provides 95 percent of the water to the Okavango Delta. They made the first part of the journey by car, abandoning the vehicles once they reached the first impassable river and carrying supplies and motorcycles through the water to the opposite bank. They traversed the final 30 miles on foot.

Finally, after several months, having collected dung samples (for DNA analysis) and captured a bit of blurry cell phone footage showing the barest glimpse of a ghost elephant lurking in thick foliage, Boyes reached what he described as a point of “complete surrender.” It was the last day of the expedition, and he and and several members of his team went out once more just before dawn. Other team members had been tracking two big bulls and Boyes et al. were able to follow the tracks, this time with master tracker Xui out in front.

About three hours in, Xui suddenly stopped and whispered, “Steve, Steve, Steve.” And an elephant walked into full view. Boyes was able to capture the footage on his cell phone—the only available camera at the time. Alas, the arrow meant to take a skin sample just bounced off the elephant’s thick hide and scared the animal away. Boyes and his cohorts pursued it for the next five hours until they ran out of water and made their way back to camp, exhausted.

On the hunt

During the elephant trance dance, the village elder faints. Skellig Rock, Inc

The genetics analysis completed thus far has confirmed that these remote elephants are indeed a new, genetically isolated species, and that Henry’s father was a ghost elephant. Boyes, as a conservationist, is deeply concerned about their continued survival. The documentary includes disturbing 1950s footage of hunters slaughtering elephants from helicopters, felling the magnificent creatures with nary a thought about the delicate ecosystem they were disrupting. “What you’re seeing in that horrific footage is the wholesale destruction of wildlife populations to make room for agriculture and development,” said Boyes. “That happened all across Africa. We lost a huge amount of wildlife over that period.”

The very remoteness and inaccessibility of their home turf has protected the ghost elephants thus far. Even if a helicopter could reach the area, it wouldn’t have sufficient fuel to get back out. But traditional Western approaches to conservation, like establishing the land as a protected wildlife reserve free of any human presence, might not be the best strategy, per Boyes, who thinks we should be taking our cues from the local inhabitants. “They can talk for days about conservation,” he said. “They have their own hunting season, sacred sites, they confiscate weapons. They manage this very closely.”

So the idea of separating people from the elephants “is counterintuitive to them,” Boyes continued. “They’re like, ‘This place will completely fall apart without us.’ We’re talking about 20,000 people in a landscape the size of England, very connected to language, tradition, and culture.” The best strategy, he feels, is for those people “to remain there as the guardians and custodians of those landscapes, and to continue to protect the elephants.”

Meanwhile, the quest to document the herd continues. Last November, Boyes was able to get samples from five different bull elephants based on the tracks they left behind. They found the tracks of 16 more members of the herd across the river, including five babies, and then the tracks of another 18 elephants.

“The gift of working with the master trackers is that you don’t to need to see them to know that they’re there,” said Boyes. “I’ve gone back three times since filming to track the elephants and I’m going back again in May. I’m going back in July. I can’t get enough of these forests. But I don’t need to see [that first elephant] again. If I do, I do.”

Ghost Elephants premieres on National Geographic on March 7, 2026, and will be available for streaming on Disney+ the following day. There is also a companion coffee table book, Okavango and the Source of Life: Exploring Africa’s Lost Headwaters.

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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A unicorn-like Spinosaurus found in the Sahara

Biology, dinosaurs, evolution, paleontology, Science, spinosaurus / Tim Belzer / March 7, 2026

A unique head spike and fish-eating jaws help make sense of these dinosaurs.

The Spinosaurus is a sail-backed, crocodile-snouted dinosaur that Hollywood depicted as a giant terrestrial predator capable of taking down a T. rex in Jurassic Park 3. Then they changed their mind and made it a fully aquatic diver in Jurassic World Rebirth—a rendering that was more in line with the latest paleontological knowledge.

But now, deep in the Sahara Desert, a team of researchers led by Paul C. Sereno, a paleontologist at the University of Chicago, discovered new Spinosaurus fossils suggesting both scientists and filmmakers might have got it all wrong again. The Spinosaurus most likely wasn’t an aquatic diver because, apparently, it couldn’t dive.

Bones in the sand

While the T. rex-beating version of the Spinosaurus was considered unlikely due to its relatively fragile skull, the newer depiction as an aquatic diver made more sense in light of paleontological evidence. Until now, all remains of these predators were pulled from coastal deposits near ancient seas and oceans. That geographic distribution was consistent with the aquatic lifestyle interpretation. If a creature lived on the coast, maybe it swam out to sea like a prehistoric seal, only crawling out to the beaches to rest just as it was depicted in Jurassic World Rebirth.

But the Spinosaurus found by Sereno and his colleagues lived in a completely different neighborhood. The fossils were discovered in the central Sahara of Niger, in what was a terrestrial area called Jenguebi. “When you want to find something really, truly new, you have to go where few have been or maybe nobody has been,” Sereno says. “In the case of Jenguebi, I don’t think it’s seen a paleontologist before.” His team managed to find the site, led by local Tuareg guides after driving for over a day and half through the desert. “We had a team of nearly 100, including paleontologists, filmmakers, guides, and 64 armed guards. You feel like you’re in an Indiana Jones movie,” Sereno recalls. But the effort paid off.

Back in the Cenomanian stage of the Late Cretaceous, the Jenguebi was an inland basin laced with rivers—a riparian habitat situated between 500 and 1,000 kilometers away from the nearest marine shoreline. In these riverbank sediments, Sereno and his team unearthed multiple specimens of the new Spinosaurus species they called S. mirabilis. The skeletons were buried right alongside massive, long-necked dinosaurs, including various species of titanosaurian and rebbachisaurid sauropods. To Sereno, the proximity of these bones left no doubt that the animals they belonged to lived and died together in the same inland freshwater environment. And this inland existence drives a pretty big nail in the coffin of the aquatic diver idea.

Prehistoric heron

The researchers point out that all large-bodied secondarily aquatic tetrapods like whales, mosasaurs, or plesiosaurs, are marine. Finding a giant Spinosaurus thriving in an inland river system strongly supports the idea that it was a semiaquatic, shoreline ambush predator that would wade into shallow waters like a giant crane or heron. But there were other hints that the Spinosaurus was not a diver.

“When you calculate this animal’s lung volume and the air that was permanently in its bones, you’ll find out it was buoyant,” Sereno explains. The permanent air sacks in the bones, an anatomical feature shared by many modern birds, most likely kept the Spinosaurus afloat even when it exhaled all the air out of its lungs. “Birds that dive get rid of those air sacks—penguins got rid of them,” Sereno says. “It’s a balloon you can’t fight against.” He added that even its limbs were far too long to be effectively used as paddles.

This wading lifestyle, the team argues in the paper, was not something unique to the S. mirabilis but extended to other Spinosaurus species as well—the skeletal features of the newly discovered S. mirabilis were found fundamentally similar to its shoreline cousins like S. aegyptiacus on which the Jurassic World Rebirth vision was largely based. Sereno argues it’s highly unlikely that one was a wading river monster while the other was a deep-diving pursuit predator with limited land mobility.

But there was one thing that made S. mirabilis different from S. aegyptiacus. The word “mirabilis” in the newly discovered Spinosaurus’ name translates to “astonishing” in Latin. What Sereno’s team found so astonishing was the prominent crest atop the animal’s head, one of the largest we’ve ever discovered.

The scimitar crown

Instead of the bumpy, fluted ridge seen on S. aegyptiacus, S. mirabilis sported a blade-shaped, scimitar-like bony crest that arched upward and backward from its snout, reaching an apex high over its eyes. This structure was composed of solid bone, unlike the highly porous, pneumatic casques found on some modern birds. However, the bone itself was etched with fine longitudinal striations and deep grooves, indicating that the bony core was just the foundation.

The newly discovered skull, along with a model of what its spike might have looked like on a living animal. Credit: UChicago Fossil Lab

In a living S. mirabilis, this crest would have been enveloped and substantially extended by a keratinous sheath, much like the vibrant growth developed by modern helmeted guinea fowls. If scaled up to a fully mature adult, the bony core alone would measure around 40 centimeters in length; with its keratinous sheath, it could have easily exceeded half a meter. For Sereno, the purpose of this “astonishing” scimitar crown was similar to crests worn today by cranes and herons. “It was asymmetrical. It varied between individuals. So, I think it was solely for display,” Sereno explains.

His team hypothesizes that visual signaling was the primary function of both the cranial crests and the massive trunk and tail sails that define spinosaurids. In the crowded shoreline and riverbank habitats, a towering, brightly colored crest or sail would be an excellent way to broadcast your size, maturity, and genetic fitness to rivals and potential mates without having to engage in a costly physical brawl.

Still, when it came down to it, S. mirabilis, weighing in at well over 7 tons, totally could brawl. “The Spinosaurus was enormous. I think it could have eaten anything it wanted even though its mainstay was fish,” Sereno says.

Crocodile jaw

The showpiece on its forehead aside, the S. mirabilis was a highly specialized killing machine. Its snout featured a low profile with parallel dorsal and ventral margins, terminating in a mushroom-shaped expansion at the tip. The upper and lower jaws allowed the teeth to interdigitate perfectly—there was a notable diastema, a gap in the upper row of teeth, that neatly accommodated the large teeth of the lower jaw. The S. mirabilis jaw structure appears similar to that of modern long-snouted crocodiles, optimized for snatching and snaring aquatic prey with a rapid, trap-like closure. Surprisingly, S. mirabilis showed greater spacing between the teeth in the posterior half of its snout compared to S. aegyptiacus despite being otherwise nearly identical.

Analysis of the animals’ overall body proportions led Sereno and his colleagues to suspect these dinosaurs resided in the functional middle ground between semiaquatic waders like herons and aquatic divers like darters, placing them in an ecological niche entirely separate from all other predatory theropods. Based on Sereno’s paper, the evolutionary history of the spinosaurids started in the Jurassic, when their ancestors first evolved that distinctive, elongate, fish-snaring skull before splitting into two main lineages: baryonychines and spinosaurines.

Then, during the Early Cretaceous, the spinosaurines enjoyed a golden age, diversifying across the margins of the Tethys Sea, a late Paleozoic ocean situated between the continents of Gondwana and Laurasia, to become the dominant predators in their respective ecosystems. What most likely brought an end to their reign was climate change.

The end of the line

The final chapter in the Spinosaurus history played out just before the Late Cretaceous, as the Atlantic Ocean was opening up. This is when spinosaurines, limited geographically to what today is Northern Africa and South America, pushed their biological limits, attaining their maximum body sizes as highly specialized shallow-water ambush hunters. This specialization, though, probably led to their extinction.

Around 95 million years ago, at the end of the Cenomanian stage, the world started to shift. An abrupt rise in global sea levels driven by climate changes drowned the low-lying continental basins and created the Trans-Saharan seaway. The complex, shallow river systems and coastal swamps that supported giant wading spinosaurines vanished beneath the waves. “We don’t see spinosaurid fossil records beyond this period,” Sereno explains. The spinosaurid lineage, unable to dive and adapt to more aquatic lifestyles, was brought to an end.

But we still don’t know much about its beginning. “This is going to be the subject of our next paper—where did the Spinosaurus come from?” Sereno says.

Sereno’s paper on the S. mirabilis is published in Science: https://doi.org/10.1126/science.adx5486

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

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Why are vertebrate eyes so different from those of other animals?

Biology, evolution, eyes, Science / Kris Guyer / March 7, 2026

“We think that in this early deuterostome, the median eye contained both ciliary and rhabdomeric cells,” Kafetzis explains. As a result, both cellular lineages were incorporated into a single, ancient, cyclopean eye, which later evolved into the vertebrate eyes.

The vertebrate third eye

A trace of this transformation may still survive in the pineal complex at the base of the brain—often referred to as a vertebrate “third eye.” Scientists have long recognized striking similarities between the retina and the pineal organ, leading many to suspect that the two evolved from a single ancestral structure, with the pineal representing a more rudimentary version.

Kafetzis and his colleagues see it differently.

Many researchers suspect that one class of neurons—the bipolar cells—is unique to the retina and represents a key evolutionary innovation of the vertebrate eye. Bipolar cells connect rods and cones to ganglion cells (hence the name “bipolar”). “We think that these bipolar-like cells already exist in the pineal,” says Kafetzis. “It’s just that they don’t look like the typical bipolar—they don’t have a cell before and a cell after.”

For this reason, Kafetzis and his colleagues argue that bipolar neurons are not a de novo evolutionary invention but instead have a chimeric origin, blending features of both rhabdomeric and ciliary cells and bridging the two photoreceptor lineages.

Though grounded in existing ideas and data, the new proposal offers a potentially far-reaching synthesis. Several aspects still require firmer evidence. The idea that the ancestral chordate adopted a burrowing lifestyle remains debated, and the claim that early bilaterians already possessed paired lateral eyes is still speculative.

The authors acknowledge that their model now needs testing. In the paper, they lay out several ways to do so—from molecular comparisons of pineal and retinal cells to developmental studies and broader sampling of eye development across other deuterostome species.

“We want to put forward some literature-based and inspired hypotheses that are testable, and now we can go out and test them,” concludes Kafetzis.

Cell, 2026. DOI: 10.1016/j.cell.2025.12.056

Federica Sgorbissa is a science journalist; she writes about neuroscience and cognitive science for Italian and international outlets.

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Asteroid defense mission shifted the orbit of more than its target

asteroid, astronomy, Dart, NASA, orbital mechanics, Physics, Science / Mike M. / March 6, 2026

The binary asteroid’s orbit around the Sun was affected by the impact.

Italy’s LICIACube spacecraft snapped this image of asteroids Didymos (lower left) and Dimorphos (upper right) a few minutes after the impact of DART on September 26, 2022. Credit: ASI/NASA

On September 26, 2022, NASA’s Double Asteroid Redirection Test (DART) spacecraft crashed into a binary asteroid system. By intentionally ramming a probe into the 160-meter-wide moonlet named Dimorphos, the smaller of the two asteroids, humanity demonstrated that the kinetic impact method of planetary defense actually works. The immediate result was that Dimorphos’ orbital period around Didymos, its larger parent body, was slashed by 33 minutes.

Of course, altering a moonlet’s local orbit doesn’t seem like enough to safeguard Earth from civilization-ending impacts. But now, as long-term observational data has come in, it seems we accomplished more than that. DART actually changed the trajectory of the entire Didymos binary system, altering its orbit around the Sun.

Tracking space rocks

Measuring the orbital shift of a 780-meter-wide primary asteroid and its moonlet from millions of miles away isn’t trivial. When DART slammed into Dimorphos, it didn’t knock the binary system wildly off its trajectory around the Sun. The change in the system’s heliocentric trajectory was expected to be small, a minuscule nudge that would become apparent only after months or years of continuous observation. By analyzing enough painstakingly gathered data, a global team of researchers led by Rahil Makadia at the University of Illinois Urbana-Champaign has now determined the consequences of the DART impact.

To find the infinitesimal deviation DART created, Makadia’s team relied mostly on a technique called stellar occultation. When an asteroid passes in front of a distant star from the perspective of an observer on Earth, the star briefly blinks out. By precisely timing these blinks as they sweep across the globe, astronomers can pinpoint an asteroid’s position with astonishing accuracy.

Between October 2022 and March 2025, we captured 22 such stellar occultations of the Didymos system. Combined with a huge dataset publicly available at the Minor Planet Data Center that included nearly 6,000 ground-based astrometric measurements taken over 29 years, optical navigation data from the DART probe’s approach, and ground-based radar measurements, researchers finally had all they needed.

“Once we had enough measurements before and after the DART impact, we could discern how Didymos’ orbit has changed,” Makadia said.

When the vending-machine-sized DART probe crashed into Dimorphos at over 22,000 kilometers per hour, it decreased the along-track velocity of the entire Didymos system by roughly 11.7 micrometers per second. But the team thinks it’s still significant. “When you do it early enough, even a small impulse can accumulate over years and cause a meaningful shift,” Makadia explained.

Also, the DART impact itself was not the only force that changed Didymos’ orbit.

The ejecta engine

The pure kinetic energy of a 500-kilogram spacecraft hitting at hypersonic speeds is impressive, but on its own, it would not slow a huge asteroid that much. When DART struck Dimorphos, it blasted pulverized rock and dust out into the void. “The material kicked up off an asteroid surface acts like an extra rocket plume,” Makadia said.

Scientists call this effect the momentum enhancement factor, denoted by the Greek letter beta. If the spacecraft impact transferred exactly its own momentum and no debris was kicked up, beta would be exactly one.

Because Dimorphos orbits Didymos, some of the ejecta remained trapped in the system, where it altered the mutual orbit between the two rocks. But a crucial fraction of the ejecta achieved escape velocity from the entire binary system. The momentum carried away by the system-escaping debris is what ultimately contributed to shoving the center of mass of the whole Didymos-Dimorphos pair. “In our case, we found that the beta parameter due to DART impact was around two,” Makadia explained.

The debris blasted completely out of the Didymos system gave the asteroids a push roughly equal to the initial impact of the spacecraft itself.

To calculate how momentum was transferred, Makadia and his colleagues had to determine precisely how massive Didymos and Dimorphos are. By linking the heliocentric deflection to the previously known changes in Dimorphos’ local orbit, the researchers were able to perform a neat mathematical trick to uncover the bulk densities of both asteroids. And this revealed something a bit unexpected about the Didymos system.

“Most studies were going under the assumption that both asteroids have equal density—turns out that assumption was not correct,” Makadia said.

A rubble pile

Based on Makadia’s calculations, Didymos, the primary body, is relatively solid. It has a bulk density of around 2.6 tons per cubic meter, which aligns with standard estimates for siliceous asteroids. Dimorphos, however, is a different story. Its density is a surprisingly low 1.51 tons per cubic meter. This implies that the smaller asteroid targeted by DART is essentially a fluffy, loosely bound agglomeration of boulders, rocks, and dust, with empty voids between the rubble.

“This was a real surprise,” Makadia said. “We previously didn’t know anything about the density of Dimorphos.” The contrast in density tells the story of how this binary system formed.

Billions of years of uneven heating and radiation from the Sun can cause an irregularly shaped asteroid like Didymos to gradually spin faster, a phenomenon known as the YORP (Yarkovsky, O’Keefe, Radzievskii, Paddack) effect. Eventually, Didymos spun so fast that the centrifugal force overcame its gravity, and it began shedding loose material from its equator. That shed material eventually coalesced in orbit, gently clumping together to form the porous, fragile moonlet we now know as Dimorphos.

Overall, Didymos is nearly 200 times more massive than its smaller companion, which explains why shifting the larger asteroid system takes such an enormous amount of force. The sheer inertia of Didymos means that the barycenter deflection of its entire system was just a tiny fraction of the deflection felt locally by Dimorphos.

Planetary defense

Makadia’s findings confirm the models we used to estimate the consequences of the DART impact: The Didymos system still poses zero threat to us, at least for the next 100 years or so. “The pre-DART condition was that the closest the Didymos system can get to Earth was around 15 lunar distances, and this has not changed appreciably,” Makadia explained.

The goal of DART was primarily to take our planetary defense out of the realm of computer models and get us some hands-on, practical experience, and Makadia thinks we succeeded in doing that. “Our work proves that hitting the secondary asteroid is a viable path for deflecting a binary system away as long as the push is large enough,” he said. “This wasn’t the goal of DART, but we can always design a bigger spacecraft.”

This experience applies both to deflecting binary asteroid systems like Didymos and singular objects. “Our results definitely help us in all sorts of future kinetic impact endeavors,” Makadia added.

The final verification of the DART mission’s consequences, though, will come in late 2026, when the European Space Agency’s Hera spacecraft will arrive at the Didymos system.

By performing independent, in-situ measurements of things like the density of Didymos and Dimorphos, Hera will provide a lot of precise gravitational and physical data that Makadia hopes to use to refine his calculations.

“It’s a high-fidelity instrument that hopefully will give us confirmation of what we believe,” Makadia said. “Plus, there are always new things to be found out when we visit an asteroid. I’m very excited about when Hera gets there.”

Science Advances, 2026. DOI: 10.1126/sciadv.aea4259

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

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How moss helped convict grave robbers of a Chicago cemetery

botany, forensic science, Science / Rejus Almole / March 6, 2026

The official records were a bit of a mess, to say the least, but the ensuing investigation revealed that while the cemetery had space for 130,000 graves, between 140,000 and 147,500 people were listed as buried there. And some areas had apparently never been used for burials. The cemetery’s then-director, Carolyn Towns, grounds foreman Keith Nicks, Nicks’ brother Terrence, and another employee, Maurice Dailey, were charged.

The only reason they were caught is because they became increasingly reckless about their grave-robbing, even using a backhoe to dig up old graves, smashing skeletons to bits as they did so. Some 1,500 bones were recovered and identified as belonging to at least 38 individuals, but between 200 and 400 graves had been desecrated, per official estimates. Emmett Till’s decaying casket was found covered by a tarp and surrounded by debris in a garage behind the cemetery. (The restored casket is now housed at the Smithsonian’s Museum of African American History.)

The evidence of the moss

The tiny bits of dirt and moss collected in Burr Oak Cemetery in 2009, which were a key piece of evidence in the criminal case. Credit: Field Museum

Prosecutors still had to prove their case. In addition to the skeletal remains, the FBI had collected broken mulberry branches and buried grass fragments for expert analysis. Von Konrat was just going about his museum business in 2009 when the FBI called, seeking expert advice on pieces of moss their team had found, inexplicably buried eight inches below the topsoil with the reburied remains. They needed his help identifying the species as well as determining how long it had been buried. This would provide the FBI with a crucial timeline of when the remains had been reburied.

“Moss is a little bit freaky,” said von Konrat. “Mosses have an interesting physiology, where even if they’re dry and dead and preserved, they can still have an active metabolism, a few cells that are still active. The amount of metabolic activity deteriorates over time, and that can tell us how long ago a moss sample was collected.” The key was chlorophyll, a green pigment central to photosynthesis. Chlorophyll degrades as a decaying plant’s cells stop functioning, so the museum team could measure how much light was being absorbed by the chlorophyll in control specimens whose age was known (both fresh and dried). Then they could compare those measurements to the forensic sample.

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TerraPower gets OK to start construction of its first nuclear plant

natrium, nrc, nuclear power, nuclear regulatory commission, power, reactor, Science, TerraPower / Kris Guyer / March 4, 2026

On Wednesday, the US Nuclear Regulatory Commission announced that it had issued its first construction approval in nearly a decade. The approval will allow work to begin on a site in Kemmerer, Wyoming, by a company called TerraPower. That company is most widely recognized as being financially backed by Bill Gates, but it’s attempting to build a radically new reactor, one that is sodium-cooled and incorporates energy storage as part of its design.

This doesn’t necessarily mean it will gain approval to operate the reactor, but it’s a critical step for the company.

The TerraPower design, which it calls Natrium and has been developed jointly with GE Hitachi, has several novel features. Probably the most notable of these is the use of liquid sodium for cooling and heat transfer. This allows the primary coolant to remain liquid, avoiding any of the challenges posed by the high-pressure steam used in water-cooled reactors. But it carries the risk that sodium is highly reactive when exposed to air or water. Natrium is also a fast-neutron reactor, which could allow it to consume some isotopes that would otherwise end up as radioactive waste in more traditional reactor designs.

The reactor is also relatively small compared to most current nuclear plants (245 megawatts versus roughly one gigawatt), and incorporates energy storage. Rather than using the heat extracted by the sodium to boil water, the plant will put the heat into a salt-based storage material that can either be used to generate electricity or stored for later use. This will allow the plant to operate around renewable power, which would otherwise undercut it on price. The storage system will also allow it to temporarily output up to 500 MW of electricity.

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Space Command chief throws cold water on the question of UAPs in space

military space, Science, Space, space command, space force, UAP / Paul Patrick / March 4, 2026

Judging from recent comments from Gen. Stephen Whiting, head of US Space Command, we shouldn’t expect anything like that in whatever the government might release in response to Trump’s pending order.

Gen. Stephen Whiting, commander of US Space Command. Credit: US Air Force/Eric Dietrich

“I can say, I, personally, was very interested in the president’s announcement,” Whiting told reporters last week at the Air and Space Forces Association’s Warfare Symposium in Colorado. “I look forward to seeing what data does come out. I can also tell you, as a space operator now of 36 years, having spent a lot of time with space domain awareness sensors, tracking things in space, I’ve never seen anything in space other than manmade objects, so I am not aware of anything that is extraterrestrial, other than comets and things like that.

“But I’m fascinated in the topic,” he continued. “And if something’s revealed, I’ll be interested as an American citizen.”

Space Command’s charge includes an area of responsibility (AOR) that extends from the top of Earth’s atmosphere to the Moon and beyond. One of its missions is to track, monitor, and catalog objects in space. Whiting suggested that everything he’s seen in orbit is attributable to a human-made or natural origin.

“We will respond to any presidential direction to go look at our files, but I think the term of art now is UAP, and the A is aerial, so these are things that are below the Kármán line (100 kilometers), that are in the atmosphere,” Whiting said. “I’ve seen some of the same videos and radar data that all of you have, and my guess is those relevant services and combatant commands will turn that data over. I’m very interested in the topic, but I have no personal experience with any of those phenomena.”

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