A crewed mission to Mars could be one of humanity's greatest achievements, but getting there may come with serious health risks. Beyond the challenges of surviving in space for months at a time, astronauts would face prolonged exposure to cosmic radiation ‪—‬ high-energy particles in space that can penetrate the human body and potentially damage vital organs.

A new study suggested that cosmic radiation could pose a particular threat to heart health. Researchers found evidence that rats that were exposed to radiation similar to what human astronauts might encounter during a mission to Mars and back developed more scar tissue around the small vessels in their hearts compared with rats that weren't exposed to space radiation.

Although the findings haven't been confirmed in humans yet, they add to the growing concerns about the long-term health effects of sending astronauts on long-duration space missions.

NASA and other space agencies are working on ways to eventually send humans to Mars and beyond. Given these latest findings, would you travel to Mars? Vote in the poll below, and let us know your thoughts in the comments.

Editor's note: The latest estimates from the Aerospace Corporation predict Swift will reenter the atmosphere at 5:19 a.m. EST on Wednesday (Nov. 4), plus or minus two hours. The earliest window for reentry opens around 3 a.m. Wednesday. NASA has not changed its estimates as of yet. This article was updated at 6 p.m. EST on Tuesday (Nov. 3).

NASA's decades-old Neil Gehrels Swift Observatory is rapidly falling out of orbit and could tumble back to Earth as early as tonight (Nov. 3), the space agency says.

According to NASA's latest estimates, shared yesterday (Nov. 2), the roughly 3,200-pound (1,450 kilograms) spacecraft will likely reenter Earth's atmosphere around 3:30 a.m. EST Wednesday (Nov. 4), with an uncertainty of plus or minus 11 hours — meaning the defunct observatory could plunge down as early as this evening.

An independent analysis from the private nonprofit Aerospace Corporation, which tracks thousands of objects in orbit, similarly estimates that the telescope will reenter the atmosphere at 5:12 a.m. EST Wednesday, give or take eight hours. Both estimates suggest the Swift spacecraft may be no more by Wednesday morning.

As with all spacecraft reentries, the risk to humans is minimal. Most of the Swift telescope is expected to burn up in the atmosphere, according to NASA. Any surviving fragments will likely fall somewhere between 20.6 degrees south latitude and 20.6 degrees north latitude — a range that includes parts of Mexico, the Caribbean, Central and South America, the Arabian Peninsula, India, Africa and Oceania, but also a lot of ocean.

NASA predicts that the chances of Swift debris falling over a populated area are approximately 1 in 2,100. For comparison, the odds of a person being struck by lightning in their lifetime are 1 in 15,300, according to the National Weather Service.

NASA will continue to update their predictions as the reentry window draws closer.

What is the Swift spacecraft?

The Neil Gehrels Swift Observatory is a multiwavelength optical, ultraviolet and X-ray telescope that launched in November 2004 on a mission to study the most powerful explosions in space. Initially designed for a two-year primary mission, the telescope ultimately spent more than 10 times that duration hunting for supernovas, gamma-ray bursts and black-hole-induced eruptions around the universe.

Swift has been rapidly losing altitude for more than a year, after rampant solar activity increased the drag on the aging spacecraft. This past August, a costly mission to boost Swift's orbit with a private spacecraft failed shortly after launch, hammering the final nail in Swift's coffin.

Engineers on the Swift team officially shut down the observatory's science operations on Oct. 20, after the spacecraft fell too low in orbit to continue taking steady observations of the sky.

As Swift goes out with a fiery bang, it leaves behind a trove of scientific data, including contributions to more than 7,000 scientific papers so far, according to NASA. This number will only increase as Swift's final observations are processed.

Earlier this year, an astronaut on board the International Space Station (ISS) snapped some striking photos, and an eerily beautiful video, of a "fireball" streaking over Earth as chunks of space debris burned up in the nighttime sky.

NASA's Chris Williams, who lived and worked on the ISS between November 2025 and July 2026, captured the eye-catching images from the station's cupola — a large, roughly dome-shaped series of windows that constantly points down at our planet — and later shared them on the social media platform X.

"Just as we were passing over West Africa, I saw a bright object directly below us, streaking through the upper atmosphere," Williams wrote in the post. "I saw its tail grow and then split apart into a shower of smaller pieces," he added. "It was quite a light show!"

Williams initially peered down at Earth to catch a glimpse of the Russian cargo spacecraft Progress 95, which successfully delivered essential supplies and additional equipment to the ISS later the same day. Instead, he saw what he believed was "some piece of orbital debris or a satellite breaking up as it entered the atmosphere."

Live Science's sister site Space.com later revealed that Williams had actually witnessed the burning remains of the Russian Soyuz rocket that had carried Progress 95 into space, after it lifted off from a recently repaired launchpad at the Baikonur Cosmodrome in Kazakhstan.

Shortly after deploying the resupply shuttle into low Earth orbit, the rocket's fairings and booster fell back toward our planet as expected, breaking apart into smaller pieces that were superheated and later vaporized by intense friction as they hit the upper atmosphere, according to Space.com. A very similar fireball was seen above Australia in August 2023, when another Soyuz rocket reentered the atmosphere.

Russia's prior resupply mission, Progress 94, also made headlines earlier this year when one of its antennae failed to deploy after separation from its Soyuz rocket, forcing cosmonauts (Russian astronauts) to use a remote control "backup system" to dock the spacecraft to the ISS.

Historically, the only fireballs visible in Earth's skies have been those caused by meteors, which can similarly break apart in flames. We were recently reminded of this when fireballs were spotted above the U.S. this spring, including one space rock that exploded with a massive sonic boom over Ohio and another that crashed through the roof of a house in Houston. (A NASA statement said the fireball Williams witnessed also may have been caused by meteor activity but was more likely to be the Soyuz rocket.)

However, fireballs from human-made objects are becoming more common. The number of spacecraft orbiting Earth has skyrocketed (pun intended) in recent decades, and "what goes up must come down."

Most spacecraft and large pieces of space junk burn up around 50 miles (80 kilometers) above Earth's surface — just below the imaginary boundary with space, known as the Kármán line. While this may lead to visually stunning spectacles like the one Williams captured, scientists are starting to realize that these fireballs may be having a bigger impact on the upper atmosphere than they previously expected.

In recent years, researchers have detected a sharp increase in atmospheric metal pollution from vaporized spacecraft. And while they are still trying to figure out what effect this may have, some scientists have proposed that it could affect the ozone layer or potentially alter Earth's magnetic field.

Additionally, as the number of falling spacecraft rises, the chances that debris may fall to Earth's surface — after failing to properly burn up upon reentry — also increase. This came to the fore in March 2024, when the remains of a 3-ton battery pack that was discarded from the ISS crashed into a family home in Florida.

See more Earth from space

Exposure to space radiation may increase astronauts' risk of a dangerous heart condition, a new study in rats hints.

The research, published Sept. 30 in the journal PLOS One, found that rats exposed to levels of radiation similar to what an astronaut might experience on a long-term trip to Mars developed more scar tissue around the small blood vessels of their hearts than rats that were not exposed to this radiation. This scar tissue is indicative of a condition known as cardiac fibrosis, which is known to increase the risk of heart failure.

This scar tissue was observed nearly a year after the rats were first exposed to the radiation.

But since this study was in rats, it cannot definitively say whether this effect will play out in humans. For example, given that humans have a longer life expectancy than rats (80 years versus 2 to 4 years), the effects seen in rats may take around 30 years to show up in humans. However, the study authors say the research highlights the importance of following astronauts' health long after they return to Earth.

"The message that we try to convey … is that the follow-up time is really important," study co-author John Baker, a professor of surgery in the Radiation Bioscience Laboratory at the Medical College of Wisconsin, told Live Science. "When astronauts come back to the Earth, they expect ‪—‬ and we expect ‪—‬ that they're going to live for a long time. I think we have to be wary that they could well develop at least some type of cardiac disease."

How space radiation affects the heart

The link between exposure to radiation and cardiac issues has been well documented. However, "no astronaut has ever been exposed to galactic cosmic radiation for long periods of time," Baker said, which makes it difficult to determine exactly how space radiation affects the heart.

Although Baker and his team previously pinpointed cardiac issues among rats exposed to radiation, this new study utilized NASA's Simulated Galactic Cosmic Ray Simulation (SimGCRSim). This new simulator provides a more precise comparison of the levels of space radiation an astronaut might experience while exploring deep space for more than a year.

During the study, the researchers exposed rats to several minutes of radiation proportionate to their size, similar to what they might experience on a trip to Mars and back (a roughly 18-month round trip, with current technology). Some of the rats' hind legs were suspended, to "simulate conditions of weightlessness," Baker said.

After 360 days, the rats that were exposed to cosmic radiation developed twice as much scar tissue around the heart's small blood vessels than unexposed rats. This buildup of scar tissue means "the heart can't relax to the point when it needs to," thereby increasing the risk of heart failure, Baker said.

This effect was not seen in the rats who were exposed only to simulated weightlessness, confirming "it was only the radiation that produced the damaging effect on the heart," Baker said. However, long-term testing revealed that this group of rats had lower levels of key immune cells, suggesting that microgravity also may affect aspects of long-term health. (Numerous studies have shown various short-term health impacts related to microgravity.)

This study "is a very valuable contribution to space biology," Rupak Pathak, an associate professor of pharmaceutical science at the University of Arkansas for Medical Sciences who was not involved in the study but holds a doctorate in radiation biology, told Live Science. While rats and humans have clear differences, "they share more than 90% of genetic information," he said, as well as very similar cardiac systems.

Given that the study authors were able to expose the rats to radiation only once, Pathak would like to see further experiments exploring whether chronic radiation exposure affects the function of the heart and other vital organs.

Baker and his colleagues hope that future experiments can be used to help NASA implement safeguards for astronauts on long-term missions, such as providing astronauts heart medications or improving shielding for the spacecraft.

"The more we know before we start, then the better NASA is going to be at working out what types of countermeasures can be developed," said Baker.

A Bronze Age man buried in a monumental tomb near the Black Sea may have died from complications of a urinary tract infection (UTI) more than five millennia ago, according to a new study. Archaeologists identified a grape-size object consistent with a kidney or bladder stone in the man's burial.

"He lived with a chronic urogenital infection," study lead author Natalia Berezina, an anthropologist at Lomonosov Moscow State University in Russia, told Live Science in an email.

"It was not a brief episode," she said. "His last years were probably marked by considerable and more or less constant pain."

Berezina and colleagues investigated a small, stone-like object found in an Early Bronze Age burial in the Stavropol Upland region of southwestern Russia. They published their findings Sept. 30 in the journal Archaeological and Anthropological Sciences.

The burial was part of a kurgan cemetery, an ancient steppe funeral tradition that involved constructing a large mound of dirt over a grave. Archaeologists discovered a catacomb when they excavated the mound, and inside was the skeleton of a man who was in his 40s when he died around 5,300 years ago. The researchers found a flint arrowhead near the man's pelvis.

But during a laboratory analysis after the skeleton was excavated, researchers noticed an odd stone-like object in the collection of hand bones. The brownish object was round with several protrusions and measured about 0.8 inches (2.1 centimeters) in diameter, or roughly the size of a grape. A small crack in the object showed a crystal-like structure inside.

To learn more, the researchers used several analytical methods to determine what the tiny object was made of. First, X-ray fluorescence analysis revealed that the main components of the object were calcium and phosphorus. Then, they used X-ray powder diffraction analysis to identify the crystal structures.

In addition to common minerals, the researchers discovered the presence of whitlockite, a rare calcium salt that is known to occur in kidney, bladder and prostate stones. These "stones," collectively called calculi, are hard masses of minerals, such as calcium-containing salts. They differ in terms of the organ they form within, the exact mechanism of how they form, and their chemical makeup, although kidney and bladder stones tend to contain very similar compounds.

Whitlockite is strongly associated with bacterial infections in the human body, which suggests that the Bronze Age man had a chronic infection that resulted in the stone, the scientists concluded.

"On the balance of the available evidence, we regard a renal [kidney] stone secondary to chronic upper urinary tract infection as the most probable origin," the researchers wrote. That is, the man dealt with chronic or recurrent UTIs, which led to the formation of the stone and likely caused him considerable discomfort. UTIs can contribute to the formation of kidney stones by altering the acidity of urine and making minerals more likely to accumulate.

The researchers aren't sure why the man had urinary tract issues or whether it contributed to his death.

Notably, kidney stones can sometimes travel to the bladder, so it's unclear exactly where the stone was in the man's body when he died. If the stone had obstructed the man's ureter ‪—‬ one of the two long tubes that connect the kidneys to the bladder ‪—‬ it may have caused kidney swelling, a secondary infection or sepsis. These conditions were frequently fatal prior to the invention of antibiotics.

Other possibilities for what caused the stone include a bacterial infection of the man's prostate gland or even a sexually transmitted infection.

The man was likely on the move frequently within this Early Bronze Age steppe society, and other injuries to his skeleton suggested he had a physically demanding life, the researchers wrote. His bones showed that he was well muscled but was also dealing with degenerative joint disease in his spine, shoulders, hips, hands and feet. He had a series of healed fractures in his right shoulder, ribs and forearm.

"These were people who worked with cattle and heavy wagons on the open steppe," Berezina said, "and the injuries that follow from that are the injuries we find." In a previous study at a nearby cemetery, Berezina and colleagues found the skeleton of a man who was injured when a wagon ran over him, several years before his death. "Against that background, four healed fractures in our man look unremarkable," she said.

But the urinary tract stone would have made the man's life difficult, the researchers noted. "This individual suffered from a painful and debilitating chronic urogenital infection, a condition that would have significantly impacted his quality of life," they wrote.

What do you know about the bones in your body? Test your knowledge with our human skeleton quiz.

Red blood cells found in a 115 million-year-old dinosaur fossil from Brazil are the oldest chemical evidence of blood-related material in a dinosaur fossil, a new study claims.

However, not everyone agrees with the research team's conclusions, with some experts saying the shape doesn't match those of reptilian red blood cells.

In the new research, published Monday (Nov. 2) in the journal PNAS, the scientists said they identified microscopic structures resembling red blood cells alongside chemical signatures of heme, the oxygen-carrying component of hemoglobin.

The new findings come from limb bones of a roughly 10-foot-long (3 meters) dinosaur called Aratasaurus museunacionali. While previous research has detected blood in dinosaur fossils, this is the first study to use chemical processes to identify heme-based signatures in dinosaur bones.

"Traditionally, fossils give us information through bones, teeth, shells and morphology. But exceptionally preserved fossils may contain another archive of information: microscopic structures and molecular traces of the original organism," study co-author Kliti Grice, a professor in the School of Earth and Planetary Sciences at Curtin University in Australia, told Live Science via email. "That opens the possibility of asking questions about ancient biology that skeletal anatomy alone cannot answer."

Deep in the bones

The team was not originally looking for traces of dinosaur blood, Grice said. Her research was driven by a broader question: How much of an ancient organism's original biology can survive fossilization?

To investigate, Grice and her team studied the limb bones of A. museunacionali, an extinct species of small theropod that lived during the Early Cretaceous period in Brazil. Theropods were a group of mostly meat-eating dinosaurs that walked on two legs. They included famous predators such as Tyrannosaurus rex and Velociraptor.

Using microscopic and chemical analysis on the theropod's limb bones, the researchers found numerous microscopic structures within vascular canals, channels that once carried blood vessels through the bone. Their shape, size and location were consistent with red blood cells, the team said.

"We combined microscopy, mineralogical analyses and molecular geochemistry," Grice said. "Critically, we investigated the chemistry in situ [in the bone itself], so we could relate the chemical signals to the microscopic structures in their physical context within the fossil. That is much stronger than simply extracting molecules from a piece of fossil and assuming where they originated."

The team's chemical analyses detected preserved heme-related compounds associated with these structures, providing more chemical evidence to support the idea that the finding could be traces of dinosaur blood, as heme is the iron-containing, ring-shaped molecule that forms a key part of the molecule hemoglobin in red blood cells.

A time capsule

Grice and the team think the conditions the theropod dinosaur was buried in could have helped preserve the vascular structures and the red blood cells within them. They suggested that the animal was rapidly covered by sediment in a low-oxygen environment containing microbial mats ‪—‬ thin biofilms made of microorganisms. These conditions may have altered the normal process of decomposition, helping to preserve the microscopic structures and associated chemical signatures.

"The red-blood-cell-like structures were mineralised with hausmannite, a manganese oxide mineral (Mn₃O₄)," Grice said. "We think early mineralisation helped stabilise or replicate microscopic biological structures before they were completely destroyed, while aspects of the associated chemistry also survived in altered form."

The fossil also contained preserved amino acids associated with collagen, the structural protein found in bone.

Not everyone is convinced

While blood has been found in dinosaur fossils before, not everyone agrees that these latest findings are truly red blood cells.

"I very much appreciate this team bringing rigor to the study of deep time fossils," said Mary Schweitzer, a molecular paleontologist at North Carolina State University who was not involved in the study but has previously studied soft tissues from the dinosaur age. "I am in agreement that endogenous [produced within the body] molecules can persist over geological time in some form, and that there is much these can teach us. However, I am not convinced that the images they figure are remnant RBCs [red blood cells] for several reasons."

For one, the structures do not convincingly match the expected appearance of red blood cells in nonmammalian animals, Schweitzer said. Unlike mammalian red blood cells, which lose their nuclei during development, those of birds and reptiles retain their nuclei. This typically produces a characteristic nuclear bulge in the shape of the cell.

According to Schweitzer, the latest findings show the microstructures having more of a concave shape with no nuclear bulge. The structures also were smaller than most non-mammalian red blood cells, "so morphological similarity is not met," Schweitzer said.

"I appreciate these authors bringing technological innovations to the study of dinosaur fossils," she said. "I am excited to see that this team and others are moving forward with a molecular approach to ancient fossil remains."

Editor's Note: This article was updated at 5:44 p.m. E.D.T. to remove an outside comment that suggested the study did not include resonance Raman spectroscopy. The team did perform that analysis.

Egyptian researchers have found a hidden 2,600-year-old structure the size of a football field after using satellites to peer below the ground. But what they found beneath the structure may be just as remarkable as the building itself.

The site they examined is known as Buto (modern-day Tell el-Fara'in), a sprawling mound of layered history in the northwestern Nile Delta. To the ancient Egyptians, it was the sacred home of Wadjet, the cobra goddess of Lower Egypt, and one of the most religiously important cities in the pharaonic landscape.

Archaeologists have excavated its upper layers for decades, finding remains from the rule of the Macedonian Ptolemaic dynasty (305 to 30 B.C.) and Roman era (30 B.C. to A.D. 395). But the deeper, older layers at the site — including a mound called Kom C, sitting below groundwater level in waterlogged delta clay — had stayed stubbornly out of reach. Kom C itself rises above the surface as a visible mound, but earlier excavations had reached only the Ptolemaic and Roman layers before hitting the water table.

Now, researchers have turned to noninvasive tools, including satellite imagery, to delve into the mysterious subterranean layers.

First, they turned to the European Space Agency's Sentinel-1 satellite, which can produce radar images by beaming down microwave pulses from orbit and then measuring how they reflect back; the returning signals can reveal subtle differences in surface moisture, elevation and reflectivity that can hint at buried structures beneath the ground. After looking at these radar images, the team spotted a large oval-shaped anomaly buried beneath Kom C that was 420 feet long and 203 feet wide (128 by 62 meters).

To learn more without disturbing the site, the team ran 15 parallel lines of electrical resistivity tomography (ERT) across an area of roughly 58,100 square feet (5,400 square meters). This technique reveals the underground landscape by passing electrical currents through the earth, measuring how they travel and creating a map that archaeologists can read.

The picture that came back was layered. Between the surface and 10 feet (3 m) down, the team found scattered Ptolemaic and Roman debris, including displaced mudbricks, pottery shards and broken limestone, which point to centuries of continued occupation and rebuilding on the site. Later residents dismantled older structures for reuse and left a scatter of displaced material behind.

Deeper still, between 10 and 20 feet (3 and 6 m), the researchers found a large mudbrick structure from the 26th dynasty (688 to 525 B.C.), also known as the Saite period. They were able to date this discovery based on its layer, the unique shape of the mudbricks and other artifacts such as pottery, which the team dated by style and their archaeological layer, with carbon-14 dating applied to associated organic material. The large structure may be a tomb, a house for priests or a religious shrine, the team wrote in the study, published in March in the journal Acta Geophysica.

And below that, at 20 to 23 feet (6 to 7 m) underground, the researchers unexpectedly found a thick, clean layer of sand.

That sand is the discovery within the discovery, the team wrote in the study.

The Nile Delta's clay is notoriously treacherous to build on. It absorbs moisture and swells, and then contracts and shifts as it dries — posing a slow-motion threat to anything heavy sitting on top of it. The Saite builders, it seems, knew this. Before laying the foundations to their structure, they packed a cushion of clean sand beneath it. This sand would have spread the building's weight, let groundwater drain through, and stopped the clay from creeping. It is the same logic behind modern load-distributing foundations — applied here more than two and a half millennia ago.

"By combining satellite radar with deep ERT profiles, we didn't just map the walls of this massive Saite-era structure — we were also able to analyze the subsurface layers," study co-author author Abdelaziz Elfadaly, an associate research professor at Egypt's National Authority for Remote Sensing and Space Sciences, told Live Science. "The detection of a significant, clean sand foundation layer beneath the mudbrick walls explains how these heavy structures survived the high water table and shifting clayey soil of Buto."

The sand layer, in effect, acts as a barrier; it stops groundwater from wicking upward into the mudbrick, which would soften and dissolve it. The sand also lets water drain sideways instead of pooling against the foundation, according to Elfadaly.

A 3-by-3 foot (10 by 10 m) excavation trench that was around 20 to 23 feet (6 to 7 m) deep confirmed the presence of thick mudbrick walls resting on that sand layer, and nearby, a spread of objects that hint at the site's sacred function. According to Elfadaly, these finds included ushabti and shawabti figurines — small servant statues typically placed in tombs to serve the deceased in the afterlife — and a limestone altar whose carved channels bore dried residues consistent with animal blood, pointing to offering rituals performed at the site. The study also noted a rarer find: a faience baboon figurine, the kind associated with Thoth, the god of wisdom.

The Saite period was a moment of cultural revival. After generations of Assyrian and Libyan domination, Egyptian pharaohs retook the throne and poured resources into restoring Egypt's religious landscape, particularly in the Nile Delta, which had been their power base. Buto, with its deep ties to Lower Egyptian identity, was a natural focus. The Saite kings ruled from the nearby delta city of Sais, so restoring Buto reinforced their roots and their claim to the throne.

"A monumental building of this scale underscores the Saite pharaohs' intense commitment to glorifying the Delta region," Hussein Bassir, director of the Antiquities Museum at a cultural research center known as Bibliotheca Alexandrina who wasn't involved with the study, told Live Science in a WhatsApp message. "Using pure sand as a stabilizing cushion was a brilliant, deliberate tactic — the ancient builders profoundly understood their environment."

The team is planning a return visit, this time using wider-spaced electrical resistivity surveys to reach deeper layers, along with specialists who study ancient plants and also understand how geological features changed over time, which may help reconstruct what the landscape around Buto looked like when these walls were first laid.

Are you a fan of mummies and hieroglyphs? Find out with our ancient Egypt quiz!

For decades, psychiatrists and other mental health professionals have used the "Diagnostic and Statistical Manual of Mental Disorders," or DSM, to diagnose patients with conditions such as major depression, anorexia and post-traumatic stress disorder (PTSD). To reach diagnoses, mental health practitioners identify symptoms via interview, case history, questionnaire, or observation to paint a clinical picture.

But for the next version of this "psychiatry bible", the DSM-6, scientists are planning to add other factors into the diagnostic criteria.

Dr. Anand Kumar, a psychiatrist who served for two years on the DSM Strategy Committee, says one of the most important potential changes is the introduction of biological factors into the diagnostic framework. While Kumar, the head of the Department of Psychiatry at the University of Illinois Chicago, no longer serves on the committee, he was influential in discussions about how biology could be incorporated into the DSM-6. Some of these biological factors include data from genome-wide association studies of hundreds or thousands of genes that each increase the risk of a mental disorder by a tiny amount. Other biological factors include signs of inflammation or immune-system dysfunction that may show up in blood tests or brain scans.

Live Science spoke to Kumar about how this update to the DSM could change the way mental disorders are understood and potentially help improve treatment.

Kenna Hughes-Castleberry: How is the DSM-6 going to be different from the DSM-5?

Anand Kumar: Up to this point, the distinctions between the different major groups — who has clinical depression, or what we call major depression; who has an eating disorder; who has PTSD, etc. — have been based exclusively on clinical grounds: You meet certain criteria, and you fall into this category. If you meet some other criteria, you fall into another category.

An attempt that's being made now, one of the major attempts for the next DSM, is to introduce biological factors into the manual.

The idea is not new. It's been discussed in the past, but it was difficult to get a consensus on what goes in and what should not go in. That's still going to be tricky, but at least there's a broad acknowledgement that the time is ready to start introducing biology into the DSM.

It's very likely that, at the end of it, there will be meaningful changes in a positive kind of way. It's not going to make everyone happy. There are going to be gaps, but the idea is to incrementally improve this and make it more modern as we go along.

KHC: What sort of biological markers have you seen that we can actually correlate with these disorders?

AK: What the committee is doing is taking a more nuanced approach. Outside the realm of Alzheimer's disease, which I'll get into in a minute, there are no clear-cut diagnostic biomarkers — meaning no blood tests or brain scans that you can look at and say, "This person has a diagnosis of depression," or "This person has PTSD," or "This person has schizophrenia."

The committee talked about how, in addition to biological biomarkers, there's a concept of biological factors. What I mean by that is biological pathways and mechanisms that have a role in the development of a particular disorder, but the findings have not crystallized into a laboratory test.

For example, immunology — the study of the body's response to a variety of stresses, including infections and others — has been shown to be impactful in about 30% of cases of major depression. Yet there is no single biological laboratory test that is currently available that can be used [to diagnose immune-mediated depression] in clinical practice. So these come under the category of what we call biological factors.

In the Alzheimer's disease field there are clear-cut biomarkers. There are now blood tests for proteins called tau and amyloid that have been approved by the FDA [Food and Drug Administration] as biomarkers for Alzheimer's disease. Meaning, if you have a clinical picture and a mental-status exam consistent with intellectual decline, you must have a positive biomarker test to be categorized as having definitive Alzheimer's disease.

And that's new. Ten or 15 years back, there were brain scans, and if you did a lumbar puncture, you could find these proteins in the spinal fluid. But those are invasive. Now you actually have a blood test.

But that degree of precision, for lack of a better term, is not available in the other branches of psychiatry. Nonetheless, there are clues that other pathways and mechanisms are involved.

I mentioned immunology as one. Another big elephant in the room is genetics.

Most people think of genetics as an abnormal gene or a mutation — meaning a gene switches or changes and confers increased risk — as one mutation causing one disease. That's how most people in the general public think about mutations: They cause disease.

But when you get into complex diseases like heart disease and diabetes, there are multiple genes involved. And diseases may or may not be caused by a gene. Abnormal genes may or may not cause the disease, but they increase risk.

With mental disorders, the situation becomes immensely more complicated. It's not just a few genes here and there. There are hundreds of genes, each increasing the risk for depression, schizophrenia and anxiety disorders by a small amount.

So while there is no single genetic test that can now be used, large numbers of genes have consistently been shown — and many of the recent studies are strong — to be associated with certain disorders. But because there's no single gene or small group of genes, we cannot walk away from the science. Complexity doesn't mean we throw our hands up and say, "Well, it's all too much."

It may seem overwhelming, but genetic profiles are better understood today than they were 20 years ago. So that's something else this committee is thinking about and I think should take into account going forward: to somehow incorporate that into the diagnostic categories.

KHC: Do you think there's any sort of risk with adding those biological factors into the DSM?

AK: I don't think so, because if you think about genetics, it's not going to be introduced as a biological test.

Most folks know that mental disorders, like other medical disorders, run in families. And genetics is the most plausible explanation for that. What this does, I hope, is introduce a degree of more comprehensive description of these disorders. So when a busy clinician looks at it, it confirms what they already suspected: There's a family history here, and family history means genetics.

It's complex, many genes are involved, and it produces a better characterization of this. The diagnosis is still going to remain clinical, but this provides a biological context, very much like, say, diabetes or heart disease.

Genes and environment cause a variety of medical disorders. With heart disease, there's no one gene. When cardiologists develop a risk profile for heart disease, it includes genes, other physiological factors such as BMI, which is the weight-height ratio, diet and a variety of environmental factors.

That degree of classification is missing today in mental health and psychiatry. We hope this is a first step in correcting, if you will, those conceptions about what causes these disorders.

KHC: How would you end up using this in a psychiatrist's office to guide treatment?

AK: I can give you one possible example. I'm reaching a bit.

There's a term commonly used in clinical psychiatry and psychology called comorbidity. What it means is that people who are diagnosed with depression also have anxiety, or people who are diagnosed with an anxiety disorder also have substance abuse or alcoholism in general.

That is not coincidental. It's not something that we just somehow find. A lot of these disorders share genes.

For example, about 45%, roughly, of patients diagnosed with a major mood disorder also have an anxiety disorder. And you flip that around: About 45%, roughly, of patients diagnosed with an anxiety disorder — it could be generalized anxiety disorder, what we call PTSD, or a phobia — also have a mood disorder.

I think when clinicians classify them together, not as the same disorder but as sharing a lot of psychological as well as genetic risk, clinicians should be on the lookout for both. A patient with a mood disorder, for example, could either now or at some later point develop an anxiety disorder. Or someone with an anxiety disorder is at risk for substance abuse.

So treatments need to be tailored a little more broadly. I'm hoping that'll be something clinicians think about when they talk to patients and their families.

KHC: What do you think is the most unique aspect, from your perspective, of this upcoming DSM-6?

AK: My bias is the biology. I say this because a lot of the other things, the cultural factors, etc., are largely appreciated, and they'll be better characterized. Some things like cognitive changes, such as working memory and attention [tests], are not unique to any given disorder.

Biology will be qualitatively new when introduced into the DSM, and I hope it's done well. I hope that they do it appropriately, and I think they will [do it] correctly.

It's not going to be perfect, but it's going to be a first step. I think introducing the idea that genetics, immunology and other factors are very important in the causation of mental disorders, and explain some of the phenomena that we previously could not find an explanation for, is — I hate to use the word "leapfrog" — but that's kind of what it is.

It moves the field conceptually forward, and not as a slow, steady, gradual increase. For the DSM, it would be an important step forward.

This interview has been condensed and edited lightly for clarity.

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The Lycurgus Cup is a Roman-era glass goblet that changes color from jade green to ruby red depending on if a light is shining on its front or back. But experts are unsure where the cup was found, where it was made, or whether the glassblower who made it created the color-changing effect on purpose.

In 1958, the British Museum acquired the cup from the Rothschild banking family, which had owned the artifact since the mid-19th century. Known colloquially as the Lycurgus Cup for its depiction of the mythical king who angered the god Dionysus, the glass is about 6.3 inches (15.9 centimeters) tall and weighs around 1.6 pounds (700 grams).

The glass is a remarkably well-preserved example of a Roman "cage-cup," according to a 1959 study of the artifact by archaeologists D. B. Harden and Jocelyn Toynbee. Only a handful of cage-cups still exist, and experts believe the goblets were made by cutting and grinding decoration into thick glass. Because small bridges were left to ensure the decoration remained on the glass, the overall effect is like a cage. Harden and Toynbee estimated that the Lycurgus Cup was manufactured in the fourth century, likely in Italy, but they noted that the bronze frame that forms the stem and rim of the goblet is probably a 19th-century addition.

Depicted on the cup is the myth of the punishment of Lycurgus, king of the Thracian tribe called the Edoni (also called the Edonians). Lycurgus did not approve of the worship of Dionysus and banished the god into the sea with an ax. But one of Dionysus' priestesses, Ambrosia, decided to fight Lycurgus. Ambrosia changed herself into a vine and wound herself around Lycurgus, who was unable to escape. The other priestesses thronged around them and tormented Lycurgus. Given that Dionysus was a god of wine and merriment, the depiction of Lycurgus' punishment may have been particularly appropriate for this goblet. Additionally, the change in color from green to red may have been meant to mimic the ripening of grapes on the vine.

Color-changing cups, also called dichroic cups, were mentioned in ancient Roman historical records. For example, a second-century letter possibly penned by Emperor Hadrian to his brother-in-law mentions a gift of two dichroic cups to use during banquets. But very few fragments of this mysterious type of glass survive today, a 2007 study noted.

For decades, experts have been working out how ancient Romans produced dichroic cups, and some have even replicated the Lycurgus Cup's color-changing effect. A 1963 study confirmed that the key seems to be the addition of microscopic nanoparticles of gold and silver during glassblowing that produce the appearance of milky-green glass when lit from the front and nearly translucent red glass when lit from behind. The metal nanoparticles are smaller than grains of sand and interact with light, creating the perception of a color change.

A replica of dichroic glass made by Corning Glassworks in the 1960s went from green to amethyst in the light, the 2007 study reported, and in 2020, researchers included silver and gold nanoparticles in 3D printing to replicate the color-changing properties of the glass.

More recently, experts at the University of Sheffield in the U.K. reproduced the dichroic glass by reverse-engineering the "recipe" from the original Lycurgus Cup. The team then commissioned a glass artist to create a Lycurgus-inspired design from the replica.

But because so few examples of dichroic glass exist, experts are still unsure whether Roman artisans created the color-changing effect on purpose or whether traces of gold, which would have been available in an ancient craft studio, slipped into the molten glass and made a rare and unusual material that mystified even the most skilled glassblowers.

For more stunning archaeological discoveries, check out our Astonishing Artifacts archives.

Can you put together last week's Astonishing Artifact?

For nine months, a scientific expedition searched for blue whales in the waters around the Galápagos Islands but found none. Between October 2025 and July 2026, the researchers surveyed areas of the Ecuadorian archipelago where the giants had historically been recorded, hoping to attach satellite tags and learn more about the animals' migratory routes. The search ended without the team tagging a single whale.

The absence coincided with unusually warm ocean conditions during an El Niño event. Sea surface temperatures were as high as 82 degrees Fahrenheit (28 degrees Celsius), while at a depth of 330 feet (100 meters) water temperatures ranged from 66 to 67 F (18.9 to 19.4 C) — up to 9 F (5 C) warmer than usual for that time of the year.

This raised the possibility that El Niño changed where blue whales were finding food and, in turn, where they went. The researchers suspect the animals may be seeking colder, more productive waters. However, the whales themselves are still missing.

"The hypothesis is that the whales are staying in areas with greater productivity [more food] farther south, in waters with slightly cooler temperatures," Daniela Alarcón, the expedition's leader and a researcher at the Universidad San Francisco de Quito's Galápagos campus and the Galápagos Science Center, told Live Science.

As to where the missing whales have gone, possibilities include the waters off Peru and offshore areas where the animals could go undetected. In this scenario, the unusually warm waters around the Galápagos Islands would act as a "temperature barrier," Alarcón said, preventing them from feeding in the archipelago's waters.

Why water temperature matters

Blue whales (Balaenoptera musculus) can consume up to 12,100 pounds (5,500 kilograms) of krill — small crustaceans that make up the whales' primary food source — every day. That means they need to find areas with enough food to sustain them.

"These are very large animals that need to move to areas where they can keep feeding," Alarcón said.

It's not yet clear whether this year's El Niño caused a krill shortage in the waters off the Galápagos, but some indirect evidence points that way.

Past expeditions suggested that blue whales tend to feed in water layers around 71 F, which this season was identified around the Galápagos at a depth of about 197 feet (92 m). By contrast, peak chlorophyll concentrations, an indirect indicator of abundance of the krill's food source, phytoplankton ‪—‬ were recorded much higher in the water column, at between 39 and 121 feet (12 to 37 m) below the surface. Because krill abundance wasn't directly measured, that data suggests, but does not establish, that there was a mismatch between the whales' preferred feeding layer and the presence of their food.

"Honestly, we had never encountered such unusual conditions before," Juan Pablo Muñoz, a marine biologist at the Universidad San Francisco de Quito who was also on the expedition, told Live Science.

Continuation of a trend

The whales' absence did not come as a complete surprise to the team. Sightings had already begun to decline before the most recent expedition. Reports submitted through Cetácea Galápagos, a citizen science network, began to dwindle between August and September 2025. There were two isolated reports of blue whales, in May and June 2026, but the team could not confirm either one, despite intensifying its search.

"We knew conditions wouldn't be the same, but we thought that if we put in more effort, we might be able to find some individuals. But we searched, and searched, and searched — and found nothing," Alarcón recalled.

Part of that could be down to the elusive nature of the giant creatures. Humpback whales (Megaptera novaeangliae)are generally easier to spot, Muñoz noted. In some places, they can be seen from the shore or after a half-hour boat ride. Blue whales, by contrast, rarely approach mainland Ecuador's coast and tend to stay far from populated areas in the Galápagos.

Sensitive to temperature fluctuations

Fernando Félix, a marine biologist at the Pontifical Catholic University of Ecuador who was not part of the expedition, was unsurprised by the result.

"We already knew there wouldn't be any blue whales in the Galápagos," said Félix, who is also a researcher at the Whale Museum (Museo de Ballenas).

Félix told Live Science that there are historical precedents for this behavior in the southeastern Pacific. During the 1982-1983 El Niño, which also brought substantial ocean warming, blue whales and other species, including fin whales (Balaenoptera physalus) and Bryde's whales (Balaenoptera brydei), were recorded shifting southward.

"We might think that because they are 'just animals,' they lack memory or don't understand these processes — but we would be wrong," Félix said. "They can clearly sense that when temperatures are unusually high as they travel north from the south, vertical mixing has been disrupted and there is no food in the Galápagos. They perceive environmental conditions and naturally direct their movements toward areas where they believe feeding conditions are better."

Rather than indicating a mass die-off, the whales' disappearance may reflect a shift in their movements in response to changing ocean conditions, Félix said.

"I don't think the whales have died," Felix said. "They simply didn't go to the Galápagos region. They went elsewhere, where conditions were better."

This response to environmental conditions may also have impacted dolphin movements. Pods may have moved toward colder waters, where food could be more abundant, or may have even dispersed, Félix suggested.

When will blue whales return to the Galápagos?

El Niño's effects will likely persist over the coming months. "Between January and May 2027, we'll have warm water coming from the north and warm water coming from the west," Félix warned. "This is going to hit us extremely hard."

Blue whales, humpback whales and dolphins would likely return to Galápagos waters once El Niño subsides and ocean conditions begin to normalize. He said pelagic fish (species that live in the water column rather than on or near the seafloor) ‪—‬ including tuna, swordfish, anchovies and sardines, which have also moved toward colder waters ‪—‬ would return as well.

Muñoz agreed. Krill populations can rebound just one to three months after cold, nutrient-rich waters begin to rise to the surface. More whale sightings were recorded in the years following the 2015 and 2023 El Niño events. Based on these precedents, he suggested that 2028 could be a promising year if cold water returns to the surface. "The system bounces back," he said.

Félix compared El Niño to a computer restart. "It resets the environment, allowing ecological processes to begin again," he said. He's confident that blue whales will return to the area. "I can guarantee that there will be large numbers of blue whales at this time in 2028," he told Live Science.

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In space, nobody can hear you scream — or meow, for that matter. This was as true for Félicette — the stray Parisian tuxedo cat who safely completed the world's first (and only) suborbital feline flight, in 1963 — as it is for the gargantuan Cat's Head Nebula, which is featured in stunning new images from the Hubble and James Webb space telescopes.

Rising from the cloudy Carina Nebula some 7,500 light-years from Earth, the Cat's Head Nebula is a column of star-sculpted gas and dust that vaguely resembles a feline sitting with its back to us, coyly turning its head to show off a single red eye. That eye is a young star that's embedded deep within the dust and possibly transforming it before our eyes.

Nebulas like these occur when the radiation from active young stars lights up and erodes the material around them. They are beautiful and easy to find; if this cosmic cat gets bored staring at us, it can just waltz over to the other side of the Carina Nebula and crawl into a similar globule of gas that looks exactly like a box with an open lid. (Cats will be cats, after all.)

In honor of Halloween, the European Space Agency (ESA) shared three competing views of the Cat's Head Nebula — one from the Hubble Space Telescope, which captures optical light, and two from the infrared instruments aboard the James Webb Space Telescope (JWST). The three views, shown below, reveal different features of the nebula in different wavelengths of light, getting progressively spookier as more color drains out of the scene.Take a look at all three images — and cast your vote for the spookiest in the poll at the end.

Hubble's view

Observing the nebula in the same visible wavelength range that you could see through a strong backyard telescope, Hubble highlights the dark pillar of dust that has survived the ultraviolet assault of nearby stars. The wispy edges at the right of the column show where starlight is evaporating the gas around it, slowly whittling it away to nothing.

The glow of blue, yellow, orange and red light around the dust pillar mark where starlight is interacting with different gas molecules, including oxygen, hydrogen and sulfur, according to ESA. The process is similar to how different molecules in Earth's atmosphere produce different-colored auroras when excited by solar radiation — just on a much grander scale.

JWST's near-infrared view

Switching to light human eyes cannot see, JWST's Near-Infrared Camera cuts through the wispier outer layers of dust to show the densest material at the column's center. Countless additional stars and galaxies appear in the field of view as their infrared glow penetrates the surrounding material.

Here we see a more complex, turbulent column, showing how stellar radiation is carving up the inside of the cat's head as well as its edges. JWST's view also illuminates a disembodied, hand-like structure to the left of the cat, reaching out as if to pet its cosmic companion.

JWST's mid-infrared view

The final view, taken with JWST's Mid-Infrared Instrument, cuts to the ghostly core of the nebula, showing little more than smoky, bluish light. According to ESA, these are the emissions of molecules called polycyclic aromatic hydrocarbons — typically colorless molecules of carbon and hydrogen related to combustion.

While most starlight disappears in this view, a strange new bright spot emerges to the right of the cat's head. This orange speck is a true mystery, according to ESA, and its relationship to the rest of the nebula is unknown.

Each year, Earth's Northern and Southern hemispheres cycle through four seasons, including summer.

Given that the hemispheres are symmetric about the equator, you may think that, on both sides of the world, summers should be similar – both in terms of their climate and factors like their length. But are Northern and Southern hemisphere summers really the same?

Climate experts tell Live Science that they differ quite a bit — and that comes with a clear recommendation for sun enthusiasts.

The most obvious difference is that Northern and Southern summers happen at different times. According to NASA, this arises because Earth's axis is tilted 23.4 degrees relative to the plane of our planet's orbit around the sun.

This tilt causes the Northern and Southern hemispheres to be oriented toward the sun at different times throughout the year. Between the Northern Hemisphere's summer solstice and autumnal equinox, the Northern Hemisphere is oriented toward the sun, resulting in summer, and vice versa in the Southern Hemisphere.

This means that summers between the Northern and Southern hemispheres sit six months out of sync with each other — with Northern summers spanning late June to late September and Southern ones going from late December to late March. (Summers are also defined meteorologically, or relative to changes in weather phenomena, as being the hottest months of the year. Under this definition, Northern summers run from June to August, and Southern ones go from December to February.)

Northern summers are longer

Another difference between Northern and Southern summers is their duration. According to NASA, Northern Hemisphere summers are, on average, 4.5 days longer than Southern Hemisphere summers. (This is with respect to the astronomical definition; meteorologically, Northern summers are longer than Southern ones by two days in non-leap years, but this is due to February being the calendar's shortest month.)

The 4.5-day difference occurs because Earth's orbit around the sun is slightly elliptical instead of perfectly circular, according to NASA. Consequently, Earth's orbital velocity (the speed at which our planet hurtles around the sun) isn't constant.

During the Northern Hemisphere's summer, Earth is farther away from the sun and thus moving more slowly, said Georg Feulner, a senior researcher at the Potsdam Institute for Climate Impact Research in Germany. This is due to Kepler's second law of planetary motion, he added.

This means that at aphelion ‪(the point at which our planet is farthest from the sun)‬ Earth is traveling at 18.2 miles per second (29.3 kilometers per second). This jumps to 18.82 miles per second (30.29 km/s) at perihelion ‪(the point when Earth is closest to the sun ) which occurs during Southern summers.

While this may seem like a tiny difference in speed, it causes our planet's path around the sun to be 53,686 miles (86,400 kilometers) shorter in a 24-hour-interval at aphelion compared with at perihelion. In other words, Earth covers more "ground" at aphelion than at perihelion over a 24-hour-interval. "Therefore, the time between the Northern Hemisphere spring and autumn equinoxes is longer than the time between the Southern Hemisphere spring and autumn equinoxes, Feulner told Live Science in an email.

Northern summers are hotter

A third point of difference is that Northern summers are typically hotter than Southern ones. A 2015 study in the journal Climate Dynamics showed the precise value of this depends on whether temperatures are measured on the surface air, land or ocean, and the latitude at which they're taken. Nonetheless, when averaged over all domains and latitudes, Northern summers are 7.83 degrees Fahrenheit (4.35 degrees Celsius) hotter than Southern ones.

So what's behind this? Earth's changing distance from the sun isn't important. If it were, Earth's aphelion crossing during Northern summers should make them cooler than Southern summers during the perihelion crossing. Instead, several other factors are responsible.

One is the Northern Hemisphere's bigger fraction of land compared to its large water bodies like oceans. "Land has a lower heat capacity than water and so increases temperature more for a given heating than water does," Richard Seager, a professor at Columbia University's Lamont-Doherty Earth Observatory, told Live Science in an email. As a result, the many inland sites in the Northern Hemisphere heat up rapidly and have higher summer temperatures, according to the UCAR Center for Science Education.

Additionally, Seager said, another difference lies in the way heat is distributed through air and water. The solar heat that land receives warms only the first few feet of the atmosphere, while the heat water absorbs gets mixed throughout its depths. This makes the Southern Hemisphere — with its larger fraction of water — cooler over summer.

The second factor for the North Hemisphere's higher summer temperatures are cross-equatorial ocean currents. Such currents cross the equator, transferring water and heat between the hemispheres. The primary current is the Atlantic Meridional Overturning Current (AMOC). "The AMOC transports heat from the SH [Southern Hemisphere] to the NH in the Atlantic," Feulner said. This warms Northern oceans and seas, which, in turn, heats up adjacent land-masses.

So, Northern Hemisphere summers are longer and hotter than Southern ones. If you want to stretch out your summer, you now know where to go.

How much do you know about our blue planet? Test your terran knowledge with our Earth quiz!

The mysterious force that cleared the cosmic fog at the dawn of the universe may not be what we thought, a new study suggests. The results hint that astronomers may need to rethink a major aspect of cosmological evolution, which led to the universe we clearly see today.

Around 400,000 years after the Big Bang, the fledgling universe finally cooled enough to form atoms — mostly hydrogen. But these neutral, non-electrically charged hydrogen atoms shrouded the cosmos in a fog that made it opaque to ultraviolet (UV) light.

Then, after the first stars flickered to life and gathered into galaxies, bursts of radiation ionized the neutral hydrogen. This turned the impenetrable fog of atoms into electrically charged protons and electrons, allowing light to pass through interstellar space unimpeded and, eventually, reach our observatories. This cosmic curtain parting is known as the Epoch of Reionization, or what a team of researchers studying it call the "last major phase transition in the universe."

"We don't know exactly what objects caused reionization or how it evolved," Cody Carr, an astronomer who focuses on galaxy evolution at the University of Michigan and first author of a new study of the epoch, said in a statement. "We know that it took place, but we don't have complete answers to those questions."

Astrophysicists previously thought that this fog-clearing effect depended on supernovas, the violently explosive deaths of stars around eight to 50 times the mass of the sun.

But in the new study, published Oct. 15 in the journal Nature Astronomy, Carr and colleagues presented evidence that supernovas exerted the opposite effect, trapping the so-called Lyman continuum (LyC) photons of ionizing UV radiation that dispelled the celestial fog instead of scattering them.

"The most interesting thing about our paper is the observation that the strongest LyC emitters do not have fast galactic winds," Carr told Live Science via email. "This challenges the notion that galaxies require fast supernova-driven winds to enable LyC escape."

Which way the winds blow

The researchers used the Hubble Space Telescope to observe an analogue of the ancient universe in the local cosmos: six star-forming, wind-launching galaxies around 3.5 billion light-years away.

These compact starburst galaxies are generally smaller than 6,500 light-years in diameter and form around 10 solar masses' worth of stars per year. That star-birthing rate is several times higher than that of the Milky Way, which is up to 20 times larger.

The galaxies' spectra, or light-based fingerprints, revealed the origin, chemical composition, speed and direction of their stellar winds, which were whipped up by the radiation from their newly formed stars.

The researchers also described how these processes changed as the massive young stars evolved and died in energetic supernovas several billion years later, with the resultant galactic winds overpowering the stellar winds.

These nearby galaxies highlighted a counterintuitive two-phase process.

In the initial phase, which occurred during the first 3 million years of star formation, the newly formed massive stars' stellar winds carved through their galaxies' neutral gas and dust at nearly 2,000 miles per second (3,000 kilometers per second). This allowed LyC light to escape the galaxy and ionize the neutral gas and dust in intergalactic space.

The second phase, which emerged around 3 million years after star formation, seemed to reverse this process. As O-type stars — the hottest, bluest and most massive stars in the cosmos — lived fast and died young, their expelled stellar guts added to the opaque galactic gas and dust, churning it and loading it with mass, which created a trap for LyC light.

The oldest galaxies in this study ‪—‬ and, therefore, the ones with the fastest supernova-generated galactic winds ‪—‬ allowed the least amount of ionizing radiation to escape their environs.

"In general, our results are in disagreement with most cosmological simulations, which typically show the LyC escape fraction peaking after the launch of supernova-driven winds," Carr explained via email. In other words, supernovas didn't drive the Epoch of Reionization, but they may have dampened it. The intense light of newborn stars now seems like the most viable source of reionization.

Future research could aim to obtain additional galactic samples and higher-resolution observations across other wavelengths.

Archaeologists have discovered a ghostly human-shaped artifact at a fifth-century burial mound in Japan. The clay figurine's appearance suggests it represents a female shaman who once guarded a tomb.

The artifact was unearthed at the archaeological site of Nishikaminomiya, northwest of Tokyo, according to a translated statement from Japan's Gunma prefectural government. At the site, archaeologists found nearly a dozen burial mounds known as "kofun" dated to the fifth and sixth centuries.

This time period in Japanese history, which lasted from about A.D. 300 to 710, is called the Kofun period. Many tombs in this period had cylindrical clay sculptures called "haniwa" that were used as offerings to the dead and were often thought to contain the souls of the deceased.

The newly unearthed haniwa is about 16 inches (40 centimeters) tall; but only the head and torso remain, so it would have originally been a lot larger. The figurine was discovered in a moat around an enormous burial mound that measured about 145 feet (45 meters) in diameter. It's likely that the haniwa was originally placed near a boat-shaped sarcophagus archaeologists discovered in the mound and that it slipped down the hill over time to land in the moat, according to the statement.

Experts think the haniwa represents a female shaman known as a "miko," or "shrine maiden." These priestesses bridge the gap between the human and spiritual realms in the Shinto religion. During the Kofun period, miko would have performed important funeral rituals and offered spiritual guidance.

The haniwa figurine has a traditional Japanese topknot hairstyle called a "shimada," which indicates that the haniwa represents a miko, according to the statement. Both of the figurine's wrists have bracelets made from clay and red pigment. The haniwa's fingers have been carefully molded, and the figurine has a prominent nose. In addition, she wears a red sash painted on her torso and holds a rod-shaped ritual implement in her left hand.

"These details suggest that considerable care was taken in making the figure, even in features that would not be visible from a distance," representatives of the Gunma prefectural government said in the statement.

Archaeologists discovered the haniwa this year during excavations of the main burial mound at Nishikaminomiya, but they have been working at the site since 2020.

The haniwa is currently on display at the Gunma Prefectural Archaeological Research Center's Excavation Information Museum in the city of Shibukawa.

The iconic nature documentary "Blue Planet" is set to return with a splash this weekend as Sir David Attenborough narrates the third installment of the BBC series. The six new episodes promise to take us deeper into the world's oceans than ever before, so wherever you are in the world, here are all the TV and streaming you need to dive right in.

The new season promises to push the boundaries of underwater wildlife filmmaking, using next-generation camera technology including "splash drones" that can land, float and take off directly from the water.

Whereas "Blue Planet II" (2017) exposed the impact of plastic pollution, each episode of "Blue Planet III" shifts the focus to "stories of hope and recovery" across five spectacular marine habitats: tropical seas, open ocean, seasonal seas, polar waters and the deep.

The sixth and final episode, "Future Seas," will look ahead to the challenges facing our oceans and what we can do to protect them for future generations.

Read on as we show you where to watch "Blue Planet III" online and on TV.

How to watch "Blue Planet III" in the U.K.

"Blue Planet III" premieres on BBC One at 8 p.m. on Sunday, Nov. 1, and will also be available to stream on BBC iPlayer.

BBC iPlayer is a free streaming platform for U.K. viewers — although you will need to confirm that you have a TV licence.

Watch "Blue Planet III" from anywhere

If you're traveling abroad you can access your usual streaming services from anywhere with a good VPN.

A VPN — or virtual private network — is a piece of internet security software that can alter your device's digital location, unlocking the geo-restrictions on most streaming platforms.

Our expert colleagues at TechRadar rate Surfshark as one of the best VPNs. Not only is it great for unblocking streaming services, it has top-level security features, a reasonable price tag and, right now, a big discount.

Can I watch "Blue Planet III" in the U.S.?

Viewers in the U.S. face a three-month wait as "Blue Planet III" won't air on BBC America and AMC+ until 8 p.m. ET/PT on Saturday, Jan. 23, 2027.

The six-part David Attenborough documentary will air weekly on Saturdays, with episodes also available to stream on AMC+.

Remember, if you're from the U.K., but in the U.S. for work or on vacation, you can use a good-quality VPN to watch your usual British streaming services from anywhere.

Can I watch "Blue Planet III" in Australia?

Australian viewers will be able to watch "Blue Planet III" on Channel Nine, which has snagged the rights to the six-part Attenborough documentary.

However, an Australian premiere date has yet to be announced.

If you're just visiting Australia, you can always use a VPN to access your usual streaming services from anywhere.

"Blue Planet III" global trailer

We test and review VPN services in the context of legal recreational uses. For example: 1. Accessing a service from another country (subject to the terms and conditions of that service). 2. Protecting your online security and strengthening your online privacy when abroad. We do not support or condone the illegal or malicious use of VPN services. Consuming pirated content that is paid-for is neither endorsed nor approved by Future Publishing.

Most trickery in nature happens without a shred of awareness behind it. An orchid mantis (Hymenopus coronatus) doesn't know it looks like a flower, and a moth with eyespots on its wings has no concept of the predator it's startling. These are adaptations shaped by natural selection over countless generations, not conscious choices. But a smaller set of animal behaviors look like something else entirely — deliberate tactical, and aimed at manipulating another individual's beliefs, the same way human lies do.

Figuring out which is which turns out to be one of the trickiest questions in animal behavior research, James O'Hanlon, zoologist and science communicator, told Live Science.

In this excerpt from his new book, "Liars, Cheats and Copycats: Trickery and Deception in Nature" (Columbia University Press, 2026), O'Hanlon explores camouflage, mimicry and misdirection throughout the natural world, building toward the book's central question: Can animals tell lies?

In it, O'Hanlon examines one of the strongest candidates for an animal that deliberately lies: the fork-tailed drongo (Dicrurus adsimilis), a small African bird whose ever-changing repertoire of false alarm calls has made it a favorite subject for scientists studying tactical deception.

James O'Hanlon interview: 'You start painting pictures of squirrels twirling their mustaches': A biologist on whether animals can lie

Fork-tailed drongos are remarkable vocal mimics and can do an uncanny impression of a meerkat alarm call. The meerkats respond to it just as they would one of their own and scamper to safety. Meanwhile the drongo flies in once more to steal the meerkats' abandoned food.

They don't stop there; drongos mimic a whole range of other animals' signals, mimicking various avian neighbors like the caped glossy starling or the pied babbler. Those ever-watchful meerkats fall for the ruse once more, leaving their meals behind. Researchers have identified over fifty unique deceptive vocalizations in the drongo's arsenal.

By constantly rotating their "cry-wolf" tactics, these birds ensure their victims don't grow wise to the deception, allowing the theft to continue unabated. Yet, their cleverness isn't reserved solely for exploited meerkats.

This remarkable talent for mimicry extends to other creatures as well. Pied babblers and sociable weavers, who both forage in groups upon the earth, frequently find themselves bamboozled into fleeing their food by these false warnings. Had the legendary boy who cried wolf possessed such adaptive ingenuity, he might have successfully maintained his trickery.

It would, however, have resulted in a peculiar fable with an entirely different, perhaps darker, moral lesson.

It's early days in our understanding of whether animals can tell lies. Social group-living animals are likely candidates for finding animal tricksters in the wild, and we have only scratched the surface of what kinds of trickery goes on in these societies. Time will tell whether similar forms of deception are happening in the subsonic songs of whales and dolphins, the chemical mists of ants and termites, or the barks and howls of wild dogs.

Despite the growing list of evidence, scientists are still hesitant to conclude definitively that animals can intentionally deceive another, in a similar way to humans. This might have more to do with the professional conduct of scientists than it has to do with the reality of what goes on in animal societies.

Firstly, one of the most important rules in studying animal behaviour is to not anthropomorphise animals. In other words, don't project human-like qualities or emotions onto other species. Scientists must be completely objective and not assume that other animals think, behave or make decisions for the same reasons we do.

Since lying has always been perceived as a human behaviour, scientists are incredibly hesitant to conclude that it could be happening in other animals.

The second reason is that scientists are trained to never definitively conclude anything. There is an idea in science that you can disprove things, but never really prove things. This is why you will find scientific writing littered with phrases like "the evidence suggests," "it's probable that," or — my personal favourite — "the most parsimonious explanation is," and so on and so forth.

A professional scientist will often give a direct "No" answer but rarely a direct "Yes." It's like squeezing blood from a stone. But this is a good thing. What often sounds like indecisiveness or a lack of certainty is actually just good professional practice. It's part of a scientist's job description — to consider all possible explanations for the observations they have made and examine every possibility on its own merits.

Then the conclusions that are drawn come down to which of these possibilities is most likely. In a universe of infinite possibilities and scales of enquiry, it would take an impossible amount of overwhelming data for scientists to exclude all possibilities but one.

This article is adapted from Liars, Cheats, and Copycats: Trickery and Deception in Nature by James O’Hanlon . Copyright © James O’Hanlon 2027, 2025 First published in Australia by NewSouth, an imprint of UNSW Press Ltd. Used by arrangement with Columbia University Press. All rights reserved.

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Most deception in nature happens without much awareness from the creature involved. From a moth that has evolved to look like a hornet to orchid mantises that mimic flowers to lure in pollinators, deception is part of these animals' nature. But in his book "Liars, Cheats and Copycats: Trickery and Deception in Nature" (Columbia University Press, 2026), biologist James O'Hanlon turns to tactical deception aimed at manipulating what another animal believes — and whether we can consider this as lying.

Live Science spoke with O'Hanlon about his book, and why so many scientists are reluctant to say "yes, animals can lie."

Read an excerpt: Can animals lie? This sneaky bird might be proof.

Olivia Maule: The chapter opens with a moment from a talk you gave, where a woman at a senior citizens' club asked you a question about orchid mantises that left you stumped: "How does the mantis know to look like a flower?" Why did that moment stick with you enough to open the chapter with it?

James O'Hanlon: Because it was such a simple, straightforward question that I couldn't give a simple, straightforward answer to. At the time, I was thinking about what's going on in the brains of the animals I was looking at — does a camouflaged animal actually know it's camouflaged? Does an insect that looks like a leaf know what a leaf even is?

And it got me thinking: they don't need to. This stuff just sort of works because it works. That's a completely different type of deception to the other things dealt with in this chapter, which is: Do animals actually know that they can lie? Can they intentionally deceive, like we can?

OM: So would you say you have an answer to that question now? And if so, what would it be?

JO: If I had to answer, it would be yes. It looks like it. But scientists are paid to be pedantic, so it's always going to be a "yes, but" or a "possibly." There's a ton of behaviors that look like animals can lie, and they're really good at it, but with any type of science, we're never going to know for certain what's going on in their brains. It's a best-guess situation.

OM: How would you help readers hold those two ideas at once — that this is genuine deception in an evolutionary sense, but not necessarily lying in the way we mean it as humans?

JO: When we talk about lying in humans, there's a value judgment attached. We're judging each other on whether we're good or bad people, doing right or wrong things. We kind of have to relax that judgment a bit when we're talking about other animals.

I guess it becomes an ethical question — we look at deception as being right or wrong, morally good or bad, and that's a very human-centric way of thinking. Ethics and morals are things we've developed to help us get along in our own societies. Who knows what's going on in animal societies?

There's an example in the book of golden snub-nosed monkeys that use deceptive alarm calls to scare off other members of their group and steal their food. After a while, those monkeys start to get ignored, and the group stops responding to their calls. So maybe there is some sort of animal-society rules and regulations keeping lying in check. Maybe. We'll see.

OM: I do want to ask about the chimpanzee study, in which chimpanzees intentionally misled competitive handlers to boxes without food, and compare it to the 2017 dog study, where dogs learned to mislead handlers much faster than the chimps did. What did that result do to the assumption that big brains equal better lying?

JO: There's always been this idea that lying is a really cognitively complex task — you need the brains not just to realize what's going on in the real world but to imagine a false possibility, and then to describe that false possibility as if it were real. We talked that up as something you need big brains to do, and there was also a bit of patting ourselves on the back for being such smart animals — maybe we lie a lot because we're such smart animals. But the more we learn about animals and what they're capable of, the more we realize they can do so much more than we thought was possible with the brains they've got.

OM: Does that suggest lying is less about raw intelligence and more a byproduct of needing to survive in a group?

JO: As far as all the examples of tactical deception in the book that look like they're intentional, they all, or mostly all, come from social animals. We don't seem to see it in solitary animals. That's a big sign that maybe it's something that's evolved because individuals can exploit it in a social setting. But it's still such early days, so it's hard to say for definite how different levels of sociality, and how bonded individuals are within groups, correlate with more deception.

OM: Could you elaborate on the distinction between deception and something like the camouflage you introduce in the book with the tiger's stripes?

JO: Compared to the intentional deception we've been talking about, things like camouflage still work regardless of whether the animal doing it is aware of it or not. The idea behind lying and tactical deception is that it only works because it's intentional — there's some sort of choice to do it.

Whether the animals are aware of that choice is another question. Think about the way we do it as humans — are we always aware of it? Whenever your friend asks whether you like their new haircut and you just go, "Yeah, it's great," you don't really think about the fact that you're probably lying. It's just part of our social norms. So it becomes a very blurry gray area very quickly.

OM: It sort of boils down to the choice of it all — whether they can choose to do it or not, which raises the question of whether it's conscious or unconscious.

JO: It's tricky, because as soon as you start talking about it being a conscious decision these animals make, you start painting pictures of squirrels twirling their mustaches, giggling at how evil they are for pretending to hide nuts. And you start to think, maybe this isn't the right exact way to think about lying and deception.

OM: The drongo — a bird renowned for its ability to deceive meerkats — doesn't just have one trick, it cycles through different alarm calls and borrows calls from other bird species. Does that put it in a different category of liar than squirrels or monkeys, or is it the same trick with a different toolbox?

JO: It could just be the same trick with a different toolbox. It's essentially doing the same thing as the golden snub-nosed monkeys we were talking about before. But birds are incredible singers and have very flexible call structures, and there are tons of birds that can mimic other birds. Maybe you just pair that ability with this deception adaptation, and it looks a bit different, but it's the same kind of trick.

OM: Do you think these behaviors are inherited, or just innate characteristics of the drongos themselves?

JO: I don't know — I'd be interested to find out. The evolutionary aspect would be that the ones who can do it get more food and are better able to survive and reproduce. Whether they learn it from their parents, it's entirely possible. We know from birds in general that they learn calls from their parents and their social groups, and there are even studies showing birds will start learning calls while they're still in the egg, listening to their parents' calls. So it's entirely possible they learn this trick socially, as far as I know.

OM: In writing this book, what did you find is the best way to approach understanding animal behavior as it relates to human traits like lying or deception?

JO: I think there's still a little bit of baggage from old-school thinking, that you need bigger brains to be deceptive and tricky in this way, and there are still people who think it must be things like the higher apes and great apes that are capable of this stuff.

As soon as you start studying that in something like an invertebrate, it's really hard to get the idea out there — other scientists will come back and say, "No, that couldn't be possible, this must be some other type of behavior, or it just looks like tactical deception, but it's not." This happened with the researchers who did the work on cuttlefish that change one side of their body to look like a male and the other to look like a female — there was a lot of resistance to that idea, seemingly just because it was a cuttlefish, this little invertebrate, so it couldn't possibly be capable of such cleverness. But as far as the actual evidence goes, and what we can see, it's really no different from what we see in these big-brained mammals, so why not assume the same thing is going on?

A lot of it comes down to the culture and practice of science, and the people doing the science. We're supposed to be as objective as possible, but we're still humans, we're still animals. It takes a while for ideas to change.

OM: Is there a risk that this caution has become its own kind of bias, where we assume human specialness by default until proven otherwise?

JO: Yeah, definitely. It's important, as part of scientific practice, to be as objective as possible, and as a general rule, to not anthropomorphize. But at the same time, we're just animals too — we're just another one of the great apes. We share characteristics with lots of different animals, so it's not a huge stretch to think that what's going on in our brains is also going to be similar to what's going on in other animal brains.

It's just a question of when we apply that kind of thinking, and when it's useful or not. Something similar happened in the field of understanding pain in animals — scientists studying this were always trying not to anthropomorphize, not to assume animals experienced pain the way we did. Then, the more we understood it, it became quite clear that they probably did, and it almost became an ethical question to stop with the anti-anthropomorphizing and instead go, no, we know what pain feels like, we can say that.

We're never going to be able to see what's going on in their brains, but that doesn't excuse us from recognizing what's going on. So I think it became okay not to anthropomorphize but to recognize the similarities between humans and other animals, as opposed to always hinging on the differences between us.

OM: At the end of the chapter, you say that if you buy a scientist a few drinks, they'll eventually admit that animals can lie. I obviously can't buy you a drink over email, so I'll just ask you directly — do you think animals can lie?

JO: Yeah. I'll give a straightforward yes, because I can.

You need to get scientists out of their professional mindset, where they're trained to give the most correct answer that they can. And yes is a bit of a broad-stroke answer for a scientist when they're in professional mode, which is why you need to get them out of the lab and out to a bar or a cafe, and get them talking in human terms again.

OM: What would you say is your favorite example in the book — what are you most excited for readers to walk away with?

JO: I'll go with the cuttlefish example — the one where a male cuttlefish will put male color patterns on one side of its body and female patterns on the other, to trick other male cuttlefish. It might be my favorite because, as a young student, I worked on this particular species of cuttlefish. We were studying them, watching all of their crazy color-changing abilities, and just wondering what on earth they must be talking about, what was going on there. Then, years later, seeing the aforementioned research come out was this sort of lightbulb moment — that's what I was watching them do all along. I think that has a personal connection for me. I spent so much time looking at these creatures, being mesmerized by what they were doing, with no idea what was going on. So it was great to see scientists come in and figure it out, and answer those questions.

This interview has been condensed and edited lightly for clarity.

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You may have heard that sharks are older than trees. And yes, sharks are truly ancient, with an evolutionary lineage dating back hundreds of millions of years.

But are they really older than trees? Experts told Live Science that the answer depends on what we classify as a shark.

"It's all in the fine print," John Maisey, the curator-in-charge emeritus of fossil fish at the American Museum of Natural History in New York, told Live Science. "The takeaway is that the shark lineage within the fishes generally does go back further than trees. But it really depends on how you define what we mean by shark."

The modern sharks we see today first emerged around 195 million years ago, during the Jurassic period. Fossils of ancient sharks from this time can be traced to living lineages, namely Hexanchiformes, an order of sharks identified by their six or seven gills and single dorsal fin.

This means that modern sharks, at least, are not older than trees. Experts generally agree that trees first evolved in the Middle Devonian epoch, around 380 million to 390 million years ago. "I think it's not very controversial, when we had the first trees," Cindy Looy, a paleobotanist at the University of California, Berkeley, told Live Science.

For instance, the first true tree in the evolutionary record is considered to be Archaeopteris, an extinct genus discovered in a 385 million-year-old fossil forest near Cairo, New York. Looking at these fossils, Archaeopteris has many characteristics of trees we have today, including a tall, woody trunk; leaves; and a deep root system. Other early trees ‪—‬ such as Eospermatopteris found in ancient forests near Gilboa, New York, and Calamophyton in southwest England ‪—‬ also appeared in the fossil record 390 million and 393 million years ago, respectively.

But when we look at the extinct relatives of modern sharks, "that's where it gets a bit wobbly," Maisey said. There are fossils from the sister groups of modern sharks that can be traced back through the Permian period and into the Devonian period (around 359 million to 420 million years ago). The most abundant group are hybodonts, an extinct group of spiny fish that have a unique calcification pattern in their cartilage that is similar to that of modern sharks.

"It’s called tessellated calcified cartilage, and that's a very important hallmark of most of the shark-like fishes and their ancestors," said Maisey, who has studied a spiny fish fossil called Doliodus problematicus from the early Devonian. If this definition is used, these sharks first appeared around 400 million years ago, before trees emerged.

Sharks' rough skin can be traced even further back, with the dermal denticles — the tooth-like scales that roughen a shark's skin — first appearing in the fossil record around 450 million years ago.

These transition fossils, where fish were evolving into sharks and gaining shark-like traits, introduce a gray area in the definition of sharks. "When you get back into the ancient past, when you're not dealing with things that we have living examples to compare with anymore, then it becomes a bit more tricky [to figure out what they are]," Maisey said.

Fossils also present a very limited picture. Many contain only fragments of an animal, like a fallen tooth, so scientists are still piecing together the clues of exactly how and when sharks arose. That means every fish fossil discovery often leads to more questions about what other transition fossils could be out there, Maisey said.

There is also much to be discovered about trees, Looy added. Terrestrial fossils, especially ones that clearly show parts of a tree, are quite rare. Finding a fossil forest requires a lot of luck, she said, although there is little indication that trees were present before the Middle Devonian.

"That's why I think the fossil record is so intriguing," Maisey said. "Because it may not give us all the answers, but it certainly raises questions."

How much of a shark fan are you? Find out with our shark quiz!

Lucid dreaming — in which the dreamer is aware that they are dreaming and can sometimes influence the dream's trajectory — is a skill that can be honed, a new study finds. And the researchers found that doing this is surprisingly easy, after training participants to do exactly that using virtual reality (VR) twice a week for just one month.

The study's results could have practical benefits, said Daniel Morris, a cognitive neuroscientist at Northwestern University who studies dreams and was not involved with the work. "Lucid dreaming can benefit people with nightmares by allowing them to transform their nightmares into positive dreams and feel greater agency in their dreams," Morris told Live Science in an email.

Before this study, published Sept. 28 in the journal Frontiers in Psychology, neuroscientists tried to induce lucid dreaming with various methods. These included meditation exercises and so-called reality checks, in which participants ask themselves while awake whether unusual phenomena they encounter — such as people wearing odd Halloween costumes — are real or if they're dreaming. The idea is that they will ask themselves the same question in their sleep during bizarre dreams.

However, "for most people, our day-to-day lives may not feel 'dream-like,'" Morris said, explaining why reality checks have had mixed results and don't reliably trigger lucid dreaming.

Since dream-like scenarios are rare in waking life, the neuroscientists behind the new study used VR simulations of bizarre situations to complement reality-check exercises.

The team, based at the University of Trento in Italy, recruited university students and asked them to meditate and then perform the VR training. The meditation was intended to increase students' awareness of what they were thinking about in a given moment. Each time they encountered bizarre happenings in the VR environment, such as objects or people violating laws of physics or rapid switches from one scene to another, they performed reality checks.

After the training, participants went home and were asked to keep a dream diary that they wrote in every morning. They also filled out daily questionnaires, citing the number of dreams they recalled and how many they remembered being lucid.

The participants experienced lucid dreams four times more often than participants did in a second group that did reality checks without performing any meditation or VR training. The study also included another comparison group, in which participants carried out reality checks during realistic rather than dream-like VR simulations; these participants were over eight times less likely to report lucid dreams. This latter comparison ensured that the results were not caused solely by the use of VR, the researchers said.

It was particularly surprising to find that such little training with the dream-like VR simulations was needed to develop lucid dreaming as a skill, said study co-author Nicola De Pisapia, a neuroscientist at the University of Trento. His team ran the experiment for only a month because any longer would have been too demanding for the participants, De Pisapia noted.

Study co-author Andrea Signorelli, a doctoral student in De Pisapia's lab, thinks the VR intervention is at the heart of why the approach worked. People often don't realize that they're dreaming because the dreams "fool" your senses and feel realistic in the moment, he explained.

"Virtual reality is the technology to fool you on stereoscopic vision and auditory information," he said. The term "stereoscopic" refers to techniques that create 3D illusions from 2D images by mimicking how human eyes see.

"It's basically the most immersive technology that we have at the moment," making it a good intervention for reality check exercises, Signorelli said.

The team also compared the number of lucid dreams participants reported against their total number of recalled dreams, which revealed an interesting pattern. On average, participants in each group recalled more dreams after starting the experiment than they did beforehand. However, the dream-simulating VR group recalled the fewest dreams overall after entering the experiment, even though they had the highest number of lucid dreams.

Signorelli speculated that perhaps it takes a lot of energy to have lucid dreams, which could divert resources away from recalling other dreams. Morris argued that, alternatively, participants in the lucid-dream VR group "may have been less motivated to report non-lucid dreams than the control groups." So there may have been some bias in the reporting.

The study had some limitations, such as its small sample size of 38 participants. Plus, neither of the two control groups were asked to meditate, so it is impossible to say whether the meditations or the dreamlike VR sessions had more influence over lucid dreaming in the test group.

The team is now doing a follow-up study in which the meditation part has been removed, Signorelli said, to reveal whether the VR dream scenarios are the critical factor, as suspected.

Signorelli said that he would like to see lucid-dream training tailored for each individual. For example, the VR simulations could be personalized to simulate a recurrent nightmare that a given person experiences, training them to recognize triggers specific to that dream, he said.

"Other future research could explore the potential therapeutic benefits of this intervention for people with nightmares, anxiety, or PTSD [post-traumatic stress disorder]," Morris suggested.

This article is for informational purposes only and is not meant to offer medical advice.

How much do you know about sleep and dreams? Find out with our sleep quiz!

When the sun inevitably dies, not even the outer solar system will be safe from the resulting chaos, new research hints.Scientists have long thought the outer solar system ‪—‬ which comprises the four giant planets Jupiter, Saturn, Uranus and Neptune — would mostly retain its present-day appearance for hundreds of billions of years to come. But a new study suggests that the outer giants may develop weirdly shaped orbits as the sun runs out of fuel, causing the planets to cross paths and destroy themselves through collisions within three billion years of the sun's transformation into a red giant.

The findings, published Sept. 21 in The Astrophysical Journal Letters, could change our understanding of what kinds of exoplanets orbit certain stars.

In about 5 billion years, the sun will balloon outward as a red giant after exhausting all of the hydrogen in its core. During this red giant phase, our star will swell to 100 times its present-day size, gobbling up Mercury, Venus and possibly even Earth in the process, Nathan Kaib, a planetary scientist at the University of Oklahoma who wasn't involved in the new research, told Live Science in an email. Following this violent swelling, the sun will crumple into a collapsed core called a white dwarf.

Until now, scientists thought the four outer planets would escape this phase relatively unscathed. A 1998 simulation-based study suggested that the gas the sun spews from its outer layers will push this planetary quartet outward, doubling the radius of each planet's orbit. Only the gravitational impact of a runaway star could destabilize this new order, and such events are thought to occur only once every billion billion years.

Solar recoil

These predictions hinged on the assumption that the sun will eject its outer layers smoothly. However, recent observations of stars suggest a jerkier loss of mass, with gas clouds lofted by plumes of plasma in the sun — as though our star were spitting out mass blobs. "They're kind of like coronal mass ejections, except much larger," Jim Fuller, a professor of theoretical astrophysics at Caltech and co-author of the new study, told Live Science in an email.

Each "blob" pushes the star backward, similar to how a fired bullet causes a gun to recoil. Although every push is small, moving the sun just a few feet per second, many pushes can, over time, impart the equivalent of an enormous kick that alters the sun's speed by several hundred feet per second. In fact, astronomers have already seen white dwarfs suffer such kicks in other star systems.

When Fuller, who studied these kicks, described them to Konstantin Batygin, a professor of planetary science at Caltech and the study's first author, Batygin "realized this would have important consequences for the evolution of our own solar system," Fuller said. That's because the kicks change the sun's gravitational pulls on everything around it.

Chaos at the edge of town

To determine how the sun's mass loss would influence the giant planets, Batygin created computer-based simulations of the sun and the outer planets. The researchers considered three scenarios: if the sun lost its mass smoothly, if it spit out distinct mass blobs during its entire time evolving as a red giant, and if the sun spewed the blobs only during its last stages. The researchers also varied each ejected blob's mass.

The first scenario produced results similar to those of previous studies, with the outer solar system retaining almost all of its features for billions of years. In contrast, the other two cases had drastically different results. Using 672 simulations, the researchers found that if the sun lost mass in blobs, the giant planets would be thrown into chaos, switching places, developing weirdly oval-shaped orbits, and even getting ejected out of the solar system entirely. Most dramatically, in 96% of the simulations with the heaviest ejected mass packets, the planets get destroyed as they crashed into each other.

These developments also happened much more rapidly — less than a few hundred million years after the sun transformed into a white dwarf, or even during the red giant phase, in the most extreme scenarios.

The study's findings hint that analogues of the present-day outer solar system around white dwarf stars are less likely to exist than previously thought. Kaib noted that the study's results suggest that planets with oval-shaped orbits should dominate instead. It's thought that habitable planets could exist around white dwarfs, but this study's findings show that our understanding of those distant star systems may be incomplete, and that such worlds may, in reality, be unstable.

See how well you know our planetary neighborhood with our solar system quiz!

While people use artificial intelligence (AI) tools to help with tasks like learning new skills or answering questions, a new study suggests that these benefits may come with a downside.

The findings, presented at the 2026 Conference on Language Modeling in San Francisco earlier this month, revealed that people who used AI assistance for reading comprehension or math problems were more likely to struggle or give up when the AI assistance was removed. The results suggest that relying too much on AI could lower people's motivations to overcome challenging situations.

In the wake of this study, Live Science recently polled its readers on whether they felt AI was making them less motivated after using it.

More than 140 readers voted in the poll, with 30% of voters picking "No, I don't use AI at all, so this situation doesn't apply to me."

"If AI were only a tool, controlled by those who use it I might give it a try," said one commenter in response. "But it isn't under control at all. It gets into your bank accounts and moves money without authorization. It encourages suicide and self-harm. It is addictive and makes people lazy. I know someone who uses it to answer questions and while it is detailed, it makes her lazier, asking one question and getting the answer without her searching for it. AI Is a danger. It should not be allowed."

Other comments reflected this sentiment, with one reader writing, "Use of all automatic aids decrease[s] attention and retention. I see it in the use of navigation devices where drivers ought to recognize routes after a couple of times. AI helps research and cuts down lengthy searches, but over use of summaries weakens critical faculties."

Other commenters questioned whether AI is the problem, or if people are just inclined to take the easy option, asking "Would you get the same results if the answers to all but a few problems were provided on separate sheet of paper?" and another writing, "I think researchers should also investigate whether shovels decrease motivation to dig holes with one's hands. AI, like a shovel, is only a tool."

Do you agree with these readers? Let us know in the comments!

Nearly 30% of U.S. adults have lied to doctors in an effort to obtain antibiotics, either by exaggerating their actual symptoms or by fabricating symptoms, the results of a new national survey suggest. Additionally, in a second survey, about one-quarter of children's caregivers reported lying about their kids' symptoms to get antibiotics on their behalf.

"As clinicians, we know that patients lie to us sometimes," Dr. Jeffrey Linder, a general internist and primary care clinician-investigator at Northwestern Medicine, wrote in a commentary about the survey findings.

However, the results are still important because the inappropriate use of antibiotics can contribute to the mounting problem of antibiotic resistance, in which bacteria build up a tolerance to the drugs designed to kill them. Recent data released by the Centers for Disease Control and Prevention (CDC) highlight the extent of the problem: In 2023, drug-resistant bacteria and fungi caused about 9.7 million infections in the U.S., up from 2.8 million in 2017. In turn, the estimated number of deaths caused by drug-resistant germs rose from 35,000 to 50,800 between the two years.

A major factor driving resistance among bacteria is the misuse of antibiotics — in other words, using antibiotics for ailments like viral infections, which the drugs do not treat. For individual patients, such prescriptions don't cure their illness and can result in an upset stomach or issues with the gut microbiome, the community of microbes in the intestines. Simultaneously, they place extra pressure on bacteria to evolve resistance, granting the germs opportunities to pick up new strategies for thwarting antibiotics.

Doctors play a big role in ensuring that the antibiotic prescriptions they write are necessary. Part of their decision-making process comes down to what patients say about their symptoms, some of which may be fabricated, the two new surveys suggest.

Motivations for lying

The new surveys were published Friday (Oct. 30) in the journal JAMA Network Open.

The first survey was completed by nearly 960 adults from across the U.S. in January and February 2026. It asked whether the respondents had ever told a healthcare provider that their symptoms were worse or more long-lasting than they were in order to get antibiotics, as well as whether they'd ever made up symptoms for the same reason. It then inquired about what motivated a given patient to lie — or avoid lying, if they were truthful — as well as posed contextual questions about their demographics, health behaviors and beliefs.

Overall, about 28% of the respondents reported misrepresenting their symptoms, including 26% who exaggerated their existing symptoms and 17% who fabricated symptoms. They most frequently lied about cold-like symptoms, such as fever, cough and sore throat. About two-thirds of these patients were at least moderately confident that their lie would motivate a clinician to prescribe them antibiotics, and 77% said the strategy worked for them at least once.

Often, patients' motivations for lying centered around feeling very sick, holding strong beliefs that antibiotics would help them recover quickly and get back to their responsibilities, and wanting control over the treatments prescribed to them. Compared with people who didn't lie, those who lied were also more likely to feel that clinicians didn't take them seriously or more likely to endorse statements suggesting that antibiotic resistance is a hoax.

"Greater antibiotic knowledge and aversion to taking antibiotics were associated with lower odds of misrepresentation," meaning lying about symptoms, the study authors noted.

Less than 30% of these patients regretted their lies or taking the antibiotics prescribed to them. Those that did express regret noted experiencing side effects, noticing that the treatment didn't help or feeling that the lying itself was morally wrong.

The second survey was much smaller; it included 236 parents and other guardians of children and teens under 18 years old. It posed similar questions but asked whether the caregivers had lied about their children's symptoms and, if so, what motivated them to lie.

About 27% reported lying about a child's symptoms to get antibiotics, with 87% of these caregivers believing that their lying worked at least once. Their reasons for lying were very similar to those expressed by the respondents in the first survey.

"These findings suggest that symptom misrepresentation may contribute to antibiotic overuse in pediatric care," the study authors concluded.

The surveys reached a diverse group of people, including a range of ages, demographics and locations within the United States; however, the respondents were not necessarily representative of the whole U.S. population, the authors noted. The prevalence of lying should therefore be seen as a tentative measure to be checked in future studies, rather than an unbiased, population-level metric, they wrote. It's also possible that not all the respondents who lied disclosed that they did so or remembered that they had done so.

Doctors are still the gatekeepers

Especially in outpatient settings, which account for most antibiotic use among U.S. patients, it can be difficult for doctors to quickly determine whether a patient needs an antibiotic.

One factor is that there's a lack of fast, surefire diagnostic tests for many bacterial infections. Outpatient appointments are also extremely short, so doctors sometimes worry about overlooking an infection that could then get worse, Julia Szymczak, a medical sociologist at the University of Utah School of Medicine, previously told Live Science. Another major factor is that clinicians can face pressure to prescribe antibiotics from their adult patients or from children's caregivers, as the new surveys reflect.

But in the face of these pressures and patients' occasional lies, Linder argues that it's still up to the clinicians to do the right thing. "While clinicians might interpret patients' symptom maximization and questions as demands for antibiotics, symptoms do not determine the indication, a diagnosis does," he wrote in the commentary.

"It does not track that approximately 80% of respondents who reported misrepresenting their symptoms obtained a prescription," he added, "unless prescribers were being willfully deceived or, more likely, just getting worn down with what they perceive as patient demand, regardless of actual clinical appropriateness."

When it comes to making decisions about individual patients, Linder argued that doctors don't necessarily need to think about the big picture of antibiotic resistance and how their patient's case fits into that global trend. Rather, providers should simply ask whether a given prescription is more likely to help or hurt that patient, he said.

"Clinicians' obligation is to act in patients' best interest," he said, "even if patients are hoping we do something different, even if patients do not like it, or even if patients lie about their symptoms."

This article is for informational purposes only and is not meant to offer medical advice.

Scientists in China are exploring what it would take to develop "the last AI built by humans" — a powerful, self-improving artificial intelligence (AI) system capable of creating its own successors.

In a new paper, researchers examine how approaches to recursive self-improvement (RSI) could help tackle the rising financial and computational costs of developing ever-more advanced AI models.

RSI refers to the idea that future AI models could direct their own training and development, using what they learn from each round of improvements to guide subsequent rounds of development.

This recursive feedback loop could eventually enable AI systems to develop newer, more powerful generations of models with minimal human input.

The study, which was uploaded to the preprint database arXiv Sept. 10 but has not been peer-reviewed, proposes a framework for classifying AI systems based on their self-improvement capabilities, from Level 1 (lowest) to Level 5 (highest).

At the lower levels, development remains largely human-led. As AI systems move up the scale, they become increasingly capable of identifying their weaknesses and deciding how to address them, eventually gaining the ability to make their own “meta-improvements” — improving how they improve themselves.

Is self-improving AI 'nonsense'?

Whether AI could ever achieve this level of sustained self-improvement remains an open question. Previous experiments have, however, demonstrated more limited forms of RSI.

In one study earlier this year, an AI system called A-Evolve-Training was tasked with improving the performance of a 30 billion-parameter large language model (LLM).

Over four rounds, A-Evolve-Training modestly improved the LLM's benchmark performance by testing different training techniques and using the results to change how it approached subsequent experiments.

Peter Bentley, a professor of digital biology at University College London, questioned whether such experiments offer a credible route to RSI.

"This idea that some AI is magically going to start generating better and better AIs by themselves [is] nonsense," Bentley told Live Science in an email.

Bentley pointed out that self-improving computer systems have been around for decades. Evolutionary computation and reinforcement learning, for instance, are both based on the principle of systems refining their performance over time in response to feedback.

The much greater challenge, he said, is developing AI systems capable of autonomously conducting the research needed to create more powerful successors — not to mention overcoming their dependence on human expertise and physical computing infrastructure.

"You can't 'recursively self-improve' unless you can also enhance your own training, enhance your hardware, and test it exhaustively in real world settings," Bentley added.

The challenge of true RSI

The study's authors acknowledged some of these challenges. Developing RSI-capable systems could require enormous investments in computing power, as well as human supervision to ensure successive improvements delivered meaningful gains. All of this becomes effectively redundant if the resources needed to develop and test subsequent AI models outweigh any benefits they offer, the authors noted.

Scientists would also need a reliable way to determine whether an AI system was genuinely becoming more capable over iterations, rather than exploiting weaknesses in tests used to measure its capabilities. This is a known problem in AI development, where models can achieve higher benchmark scores by exploiting testing methods or cherry-picking results.

Kayla Blomquist, an AI researcher at the University of Oxford and co-founder of the Oxford China Policy Lab, said that, while the paper doesn't provide a practical road map to RSI, it could help developers and policymakers understand the technical challenges and safety risks associated with increasingly autonomous AI systems.

She also questioned whether there would ever be a clear point at which AI became completely independent of human development. "The paper describes a gradual handover of responsibility rather than a single moment, so there may never be an obvious 'last' model built by humans," Blomquist added.

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The Vera C. Rubin Observatory has found what might be a tiny new world in the far reaches of our solar system, hidden beyond the orbit of Neptune — and it is among the largest and brightest objects ever discovered beyond Neptune.

If confirmed, the miniature world would increase the number of officially recognized solar system dwarf planets to six. Upper estimates of the object's size place it at more than half the diameter of Pluto, the largest known dwarf planet.

"My first reaction was one of excited disbelief," Matthew Holman, an astrophysicist at the Smithsonian Astrophysical Observatory and member of the Rubin team who wrote the code that helped discover the prospective dwarf planet, said in a statement. "Objects like this are very rare, so I immediately started checking whether I or the code had done something wrong."

Hidden among stars

The potential dwarf planet, designated 2026 ED138, orbits the sun at roughly 46 times the distance between Earth and the sun. The potential new planetoid has been hiding behind galactic camouflage; with its orbit tilted at a 25-degree angle from the solar system plane, it's at just the right angle to get lost in the light from the inner Milky Way, the researchers said.

Many telescopes struggle to see past the millions of stars making up our galaxy's bulge. The Vera C. Rubin Observatory, however, images the entire southern sky every few nights with the largest digital camera ever built, sending out millions of nightly alerts for every object that has changed brightness or position. This makes it exceptional at identifying anything that moves, from solar system objects to transient events like supernova explosions.

The observatory had only just begun its 10-year mission of scanning the sky in July, and ED138 stood out in the data.

Holman works on the software algorithms that process the extreme amounts of data the observatory collects. The code he developed with his colleague, Kevin Napier, compares billions of observations to determine which ones are detections of the same moving object. Running data from Rubin through the code revealed the unusually large object.

By looking at past data from Rubin and archival images from the Dark Energy Camera mounted on the Victor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (both in Chile), the team was able to map out ED138's orbit over the past 10 years.

Going beyond Neptune

The Kuiper Belt is a region of the solar system beyond Neptune that is a wild frontier of small, mostly icy bodies made from frozen methane, ammonia, water and rock. It ranges from roughly 30 to 50 times the distance between Earth and the sun, and is home to most of the known dwarf planets, including Pluto. Thousands of Kuiper Belt objects have already been discovered. These space rocks can be frozen time capsules that hold clues about the early solar system's formation.

Dwarf planets are the largest Kuiper Belt objects that we know of. Bigger than asteroids but not quite planets, dwarf planets are big enough to be rounded under the force of their own gravity but too small to clear their orbits like planets do. While the International Astronomical Union (IAU) has officially confirmed five dwarf planets — Pluto, Ceres, Eris, Haumea and Makemake — astronomers studying dwarf planets often recognize at least nine, with several more candidates whose properties are still unknown.

Depending on which astronomer you ask, there could be anywhere from a handful to hundreds of dwarf planets in this part of the solar system. Identifying which Kuiper Belt objects are dwarf planets is tricky because they are often very dim and move very slowly from Earth's perspective, since their orbits are so large and distant. The likeliest candidates have high albedo (surface reflectivity) and diameters greater than roughly 370 to 500 miles (600 to 800 km).

What makes ED138 special is its size, inferred from its brightness, albedo and distance from the sun. It's estimated to have a diameter between 370 to 930 miles (600 to 1,500 km). For comparison, Pluto — the largest dwarf planet recognized by the IAU — is 1,477 miles (2,377 km) in diameter. Ceres, the smallest IAU-recognized dwarf planet, is 595 miles (958 km) in diameter. Future observations of ED138 will give researchers a more accurate idea of its diameter and density to determine if it's round enough to join the dwarf planet club.

"If confirmed as a dwarf planet, ED138 would join a very small family of worlds," Holman said in the statement. "Rubin will image the whole southern sky again and again for ten years, so any others hiding in the places earlier surveys skipped are now within reach."

On the last day of an ecology field trip to Virginia's Eastern Shore, a biology undergraduate student discovered more than she expected. While searching for shark teeth, Brooklyn Rolph, a student at Mary Baldwin University in Virginia, stumbled upon a stone spearpoint estimated to be around 4,500 years old.

"Wow, this is so crazy," Rolph said in a statement. Already primed to look for pointy objects underwater, Rolph found a stone spear and immediately alerted the professors running the trip. "They were ecstatic," she recalled.

The stone artifact is about 6 inches (15 centimeters) long and, according to local archaeologists, a type known as a Lehigh/Koens-Crispin point. This kind of stone tool was made by Indigenous people across the East Coast of the U.S. from around 4,500 to 3,000 years ago. Sometimes called a "broadspear," the stone point also may have been used as a knife by prehistoric hunter-gatherers in the Late Archaic period.

The field trip was part of an ecology course led by Mary Baldwin University faculty members who had secured a permit from the state to explore the barrier islands off the Eastern Shore, the southern part of the Delmarva Peninsula that includes most of Delaware and parts of Virginia and Maryland.

Just after a lunch break on Sept. 21, the last day of the excursion that aimed to let students study plants and animals in the coastal ecosystem, Rolph set out to quickly explore a mound of shells on the island and noticed the spearpoint at the edge of an inlet. Her professors were blown away by the lucky discovery.

"The set of circumstances that came together that made this possible is quite unbelievable," Paul Callo, a biology professor at Mary Baldwin University who was co-leading the trip, said in the statement. "The tide was coming in, so the spear point was soon to be buried."

When Rolph showed Callo the artifact, he was "truly at a loss for words," he said. "It is certainly awe-inspiring to see and touch something that was made by human hands thousands of years ago."

The barrier island where Rolph found the stone point is part of a natural area owned by the Virginia Department of Conservation and Recreation, which means the artifact is now the property of the Commonwealth of Virginia. Archaeologists collected it from the Mary Baldwin group and have taken it to the Virginia Department of Historic Resources for further study.

Rolph was fine with not keeping the spearpoint. "That's how you get cursed!" she said.

How much do you know about the first people to reach the Americas? Find out with our First Americans quiz!

Researchers have virtually reconstructed the face of a man who was decapitated after his death almost 2,000 years ago and then buried near a Roman military fort in Scotland.

While it's unclear why the man was beheaded, other burials hundreds of miles away may offer a clue. A chemical analysis of the man's remains suggests that he grew up in southern Britain. Beheading bodies may have been an obscure burial rite for some southern Britons, as other decapitated bodies from about the same time have been found in that region, John H. Reid, an archaeologist at the Trimontium Trust who was not involved in the excavations, told Live Science.

Another mystery is why a southern Briton was on the Roman frontier, but it seems that he was working for the Roman army when he died, researchers at National Museums Scotland said in a statement. However, his skeleton shows the man's right arm had such limited movement that he could not have used a sword, so he was probably not a soldier, they added.

Despite this disability, however, it's possible that the man used weapons in his other hand, or had a job in the Roman army that did not require frontline fighting, such as a clerk.

"He could have been left-handed, or he could have had a 'desk job'," said Reid, who is the author of the book "The Eagle and the Bear: A New History of Roman Scotland" (Birlinn, 2023).

The man was probably about 50 years old when he died between A.D. 142 and 165. His remains were then buried near the Roman fort at Inveresk, on Scotland's east coast just southeast of what's now Edinburgh, according to the statement.

An analysis of the man's skeleton indicated that he had lived an active life. His nose had been broken and healed, and his right elbow showed extensive bone growth, perhaps from arthritis. Reid said the bone growth may have been his body's response to a physical injury.

Researchers at National Museums Scotland and the independent U.K.-based forensic anthropologist Christopher Rynn created the facial construction based on the man's skull.

Romans in Scotland

The Roman fort at Inveresk was built around A.D. 140 and acted as a command-and-supply center for Roman forts along the Antonine Wall, which ran along the shortest route between Scotland's west coast and east coast — roughly the line between Glasgow and Edinburgh, although neither city existed at the time.

The Romans had hoped to secure all of Scotland under their rule after their invasion of Britain under Emperor Claudius in A.D. 43. They tried to impose control after their victory against a coalition of native Caledonian tribes at the Battle of Mons Graupius (possibly near the Scottish city of Perth) in about 83. But by about 120, the Romans had retreated to the heavily fortified line of Hadrian's Wall, near the modern border of England and Scotland.

The fort at Inveresk was built for a second push that aimed to secure Roman control over southern Scotland by establishing the Antonine Wall. But this failed too, and after A.D. 162, the Romans withdrew again to Hadrian's Wall, until the final collapse of Roman rule in Britain in the early fifth century.

Strange burial

Reid told Live Science that Scotland's soil seldom preserved human skeletons, making the discovery of a Roman-era burial an uncommon find. Although the man had been decapitated after his death, other aspects of his grave indicated he was buried with dignity. In other words, his burial was unlike those of executed criminals, who were often decapitated in Roman-era Britain, he said.

The remains from six Roman-era burials have been found at Inveresk, and four of the dead had been similarly beheaded, the statement said.

There are several ways non-Romans could have served with the Roman army, Reid told Live Science. They might have been employed as servants or artisans attached to the Roman legions, or they might have been soldiers in Roman auxiliary units or even citizen-based legions, he said. By the time of the Antonine Wall, few members of the Roman army in Scotland would have been from the Italian peninsula, he added.

The chemical analysis looked at the ratios of isotopes, or variations of chemical elements, in the man's remains. This analysis suggested that the man had grown up in southern Britain. Alternatively, he may have been recruited from a nearby region, such as the coast of what's now the Netherlands, that gave the same isotopic profile, Reid said.

Reid and his colleagues have found extensive evidence of the Roman army at the Burnswark site in southern Scotland, including the deadly whistling sling bullets they used against their "barbarian" foes. Archaeological work there is ongoing.

What do you know about the Empire's conquest of the British Isles? Find out with our Roman Britain quiz!

Deep in a limestone cave on Turkey's Mediterranean coast, two very different sets of humans left behind nearly identical traces of their lives — similar stone tools, the remains of the same prey animals, the same types of seashells pierced and strung into ornaments. They may have been separated by thousands of years and may not have directly interacted. Yet the overlap between them was striking enough that researchers studying the site had to look twice.

The site, Üçağızlı II, offers one of the clearest examples of a conundrum that scientists have long wrestled with: Neanderthals and modern humans (Homo sapiens) didn't just collide and go their separate ways. They inhabited the same areas, and, as dozens of genetic studies have confirmed, had sex, across tens of thousands of years and on multiple continents. The DNA of nearly every person alive outside Africa today carries the proof: Roughly 2% of the non-African genome is Neanderthal.

And yet, there is not a single archaeological site that shows them living together. Knowing that modern humans and Neanderthals mated is not the same as understanding how it happened. Who approached whom? Were these interactions consensual? Were they the result of violence or trade alliances? Who raised these hybrid babies? And what does the genetic record tell us about the social lives of two different kinds of humans navigating each other's existence for the first time?

Some of the answers, it turns out, are written on the X chromosome — and they are stranger than expected.

A puzzle on the X chromosome

The first high-coverage Neanderthal genome was sequenced in 2010, and for the next 15 years, researchers kept noticing something puzzling: Neanderthal DNA was less common from the X chromosomes in people alive today.

One of the two sex chromosomes in humans, the X chromosome represents about 5% of the DNA in cells. Most females carry a pair of X chromosomes in each cell, while most males have one X and one Y.

Everywhere else in our genome, traces of long-ago breeding between Neanderthals and modern humans showed up in roughly consistent proportions. But on the X chromosome, there was far less Neanderthal DNA.

The leading explanation was negative selection — the idea that Neanderthal gene variants unique to the X chromosome were somehow incompatible with modern-human biology and had been gradually eliminated from the gene pool over thousands of generations. It was a reasonable hypothesis, given that incompatibilities elsewhere in the genome did lead to the weeding out of Neanderthal DNA on other chromosomes over time.

To understand why the negative selection explanation didn't explain the X chromosome data, however, it helps to know what different parts of the genome actually do. Some stretches of DNA are protein-coding regions; they contain the instructions for building proteins, the molecular machinery that does most of the work inside cells. Others are regulatory sequences that don't build proteins themselves but help control when and how much of a protein gets produced. And then there are still other stretches of DNA that don’t appear to code for proteins or directly regulate gene expression, though researchers suspect at least some have functions we don’t yet fully understand.

Alexander Platt, an evolutionary biologist at the University of Pennsylvania's Perelman School of Medicine, hypothesized that if the problem was that Neanderthal gene variants on the X chromosome were inherently harmful, modern-human X gene variants would have been advantageous in Neanderthals. As a result, X chromosomal DNA extracted from Neanderthal skeletons should show an excess of modern-human DNA in stretches of the genome where they'd provide measurable benefit. They reasoned that this excess would likely appear in protein-coding genes or the regulatory regions that control their expression, not noncoding DNA.

But that's not what they found. Instead, Neanderthal X chromosomes carried more modern-human DNA in the noncoding regions of the genome than in coding regions. This pattern didn't reflect selection for better gene variants. It was a signature of reproduction ‪—‬ a record of who was passing chromosomes to whom.

In a typical pregnancy, the mother contributes an X chromosome via the egg, and the father contributes either an X or a Y via the sperm cell. So, while an individual is guaranteed to inherit their mother's X, they don't necessarily carry their father's — males exclusively inherit their mother's X. That pattern differs from the other 22 pairs of chromosomes, which mothers and fathers contribute to equally. Across a population, then, two-thirds of X chromosomes are inherited from mothers and one-third from fathers.

This fact makes the X chromosome a particularly sensitive recorder of who was reproducing with whom.

Long-standing sexual preference

Tracking the flow of X chromosomes can reveal trends in Neanderthal-human mating. If Neanderthal males paired with modern-human females more often than Neanderthal females paired with modern-human males, you'd see more modern-human X chromosomes flow into the Neanderthal gene pool.

When the team ran simulations to explore this idea, the data suggested what Platt described as a persistent, recurring mating preference: Males with more Neanderthal ancestry tended to reproduce with females with more modern-human ancestry. And this trend held across at least two distinct mating periods separated by around 200,000 years, said Platt.

This finding gave the researchers a new window into the timeline of mating between Neanderthals and modern humans. Platt's team identified at least two distinct pulses: one roughly 45,000 years ago, which produced the majority the Neanderthal DNA that lives on in non-African genomes today, and an earlier period over 200,000 years ago, whose genetic traces survived not in modern-human populations but in Neanderthals.

The pattern of Neanderthal males having offspring with H. sapiens females appears in both periods, separated by more than 150,000 years.

What the X chromosome data alone cannot say is why the pattern exists. It documents who reproduced with whom. It says nothing about who wanted whom.

Biological incompatibility

That distinction matters, because the same genetic signature can emerge from very different causes, and some have nothing to do with sexual preference.

Rajiv McCoy, a geneticist at Johns Hopkins University, pointed out that biology alone could produce a genetic signal like this one. When closely related species interbreed, the success of a pregnancy can depend not just on whose genes are inherited but on which parent belongs to which group.

Even if Neanderthal genes work fine in a modern-human genetic background, hybrid pregnancies may simply have been more likely to succeed when the Neanderthal was the father rather than the mother. That's not because of either parent's sexual preferences, but because of how their respective biologies interacted in the womb, McCoy told Live Science.

Researchers have recently proposed a few mechanisms that fit neatly with this theory. One study suggests that Neanderthal red blood cells restricted fetuses' growth in the womb. Another proposed that Neanderthal mothers carrying hybrid offspring may have been more prone to preeclampsia, a life-threatening pregnancy complication. Nothing in the existing data definitively rules such causes, McCoy said.

In practice, the two explanations are hard to separate. "Our models have no way of distinguishing mating from mating that produces a viable and fertile offspring," McCoy said. If hybrid pregnancies failed more often when the mother was Neanderthal, the genetic record would look similar to a world where Neanderthal females mated less often with H. sapiens males. Sexual encounters that didn't result in offspring left no genetic trace.

For now, the question of what drove that bias — social preference, or biology — remains open. Whatever barriers existed between the groups, they clearly weren't absolute. Multiple distinct episodes of interbreeding over thousands of years, McCoy noted, is itself evidence that the fertility of hybrid individuals was "sufficiently intact to leave a lasting mark."

How Neanderthal and human groups interacted

Bridget Alex, a researcher in human evolutionary biology at Harvard University who has spent her career reconstructing the timing and geography of Neanderthal-H. sapiens overlap, cautioned that all this is hampered by one fact: no direct archaeological evidence reveals how the two groups interacted.

"Despite a century and a half of Neanderthal research," she told Live Science, "no one's ever found a Neanderthal and Homo sapiens fossil in the same exact layer dated to the same exact period at the same exact site."

Instead, we have a regional and variable patchwork shaped by conditions that shifted over thousands of years and hundreds to thousands of miles.

Neanderthals inhabited a territory stretching from Siberia to Iberia to Southwest Asia between roughly 250,000 and 40,000 years ago. Modern humans were evolving in Africa during much of that span and came out repeatedly, in multiple waves, meeting Neanderthals in different times and places, with likely very different outcomes each time, Alex said.

"It's not like the Neanderthals living in what's now Spain could call up the ones in what's now Uzbekistan and be like, 'OK, what's our policy with modern humans? Do we kill them, have sex with them, ignore them?'" she said. "My assumption has always been that interactions would vary across time and space depending on the particular environmental conditions, social conditions, and just the whims of a particular group."

At Grotte Mandrin, a cave in the Rhône Valley in southern France, archaeologists found one of the most illuminating records of what those encounters may have looked like. Ludovic Slimak, a paleoanthropologist at the University of Toulouse who has spent years excavating the site, described it as something genetics alone can't offer: "an extraordinarily precise archaeological sequence of Neanderthals and [Homo] sapiens occupying exactly the same place," he told Live Science in an email.

Neanderthal artifacts fill layer after layer of radiocarbon and luminescence dating up to about 57,000 years ago. And then, in one thin layer dated to between 56,800 and 51,700 years ago, there's a set of different stone tools and a single tooth that appear to belong to H. sapiens. Then, in layers immediately above, beginning around 51,700 years ago, Neanderthal artifacts appear again. That group of modern humans arrived, lived briefly in a continent otherwise inhabited entirely by Neanderthals, and then disappeared.

"What strikes me most is not mixture but proximity without fusion," Slimak told Live Science in an email. In other words, the two groups left no trace of cultural exchange or shared practice.There were "two human populations occupying the same landscape, probably encountering one another, while remaining culturally and biologically very different," Slimak said.

Genetics also paints a portrait of two very different social architectures. Two sites exemplify the trends: At Sunghir, a burial site in Russia dating to around 34,000 years ago, two H. sapiens adolescents were interred head to head beneath thousands of ivory beads and mammoth-bone spears. Ancient DNA analysis showed they were not immediate family members, yet they were buried together in an elaborate ceremony that implies a social world much wider than their immediate group.

In contrast, at Chagyrskaya, a cave site in Siberia, Neanderthals buried in what appears to be a single community layer included a father and his teenage daughter, and a second pair of individuals who shared roughly a quarter of their DNA.

While these are just two sites, they reflect a broader trend that shows up repeatedly in genetic data: Human groups tended to operate through what Alex described as a nested structure: Tens of thousands of years ago, small groups of perhaps 20 or 30 individuals maintained broader ties through ceremonies, intermarriage between human groups and exchange with other groups.

In contrast, data from Neanderthal sites reveal that they tended to cluster in small, tightly knit groups that remained relatively separate from other Neanderthal populations.

Unlike modern humans, Neanderthals didn't regularly mate with individuals in other communities, Alex said. The result, written in their genomes, is that individuals within a single Neanderthal group were often closely related. Their genomes show low genetic diversity across the board, — "kind of suggesting they're always a population on the verge," Alex said, "like an endangered species."

Still, there had to be some out-group mating. At sites where researchers have extracted genomes from several Neanderthal individuals, the pattern is consistent: Male Neanderthals were more closely related to each other than female Neanderthals were to each other. Females, by contrast, seemed more likely to have come from elsewhere. This is the signature of a "patrilocal" social structure in which males stay in their birth groups and females move between them.

Neanderthals' insularity sharpens a key question: If Neanderthal groups weren't regularly folding in Neanderthal females from distant communities, they would probably be even less likely to incorporate female H. sapiens. So how did modern-human women end up producing offspring with Neanderthal men at all?

A numbers problem

Fernando Villanea, a population geneticist at the University of Colorado Boulder, thinks the question may be framed backward. The image of Neanderthal males raising hybrid children with modern-human females within Neanderthal communities, he argues, probably inverts what actually happened.

Something the genomes of late Neanderthals — those living toward the end of their long history in Eurasia — make clear is that they were roughly 10 times more inbred than the modern human ancestors who were then expanding out of Africa in large numbers, he noted. That level of inbreeding isn't usually a choice; it reflects how small and fragmented Neanderthal populations likely were.

Archaeological and paleoclimatic data fill in the context: The ecosystems Neanderthals were best adapted to were shrinking as the planet entered a warmer, more humid period. Modern humans, who had evolved in hotter, wetter African environments, were simply better suited to Europe's new conditions, experts think.

The resulting numerical imbalance changes how scientists think about mating between Neanderthals and modern humans.

"We need to imagine scenarios where a majority of modern human groups traveling into Eurasia are encountering a vanishing minority of Neanderthals," Villanea told Live Science.

In the crucial period between roughly 50,000 and 44,000 years ago, when much of the interbreeding that left a trace in our DNA took place, Neanderthal DNA made up 5% of the modern human genome. Given how heavily humans outnumbered Neanderthals at the time, "that's a lot of matings occurring between the two." The most likely story, Villanea proposes, is "human groups absorbing surviving Neanderthal individuals and raising their children in a mostly human group."

His 2018 study in the journal Nature Ecology & Evolution established that this happened across multiple distinct episodes — and the later ones are particularly telling. Some ancient H. sapiens genomes from Europe around 40,000 years ago, according to the study, carry Neanderthal ancestry from individuals who lived just a few generations after archaeologists can no longer find any physical trace of Neanderthals in the region at all.

Even the very last Neanderthal survivors were still contributing to the H. sapiens gene pool. A 2024 study by Leonardo Iasi and colleagues similarly determined that almost 90% of total Neanderthal ancestry in humans today came from a main pulse roughly 50,000 to 45,000 years ago, likely in the Middle East, with the rest trickling in from more sporadic encounters scattered across Eurasia.

That paints a picture of meetings becoming rarer and rarer as Neanderthals disappeared, with hybridization continuing whenever they did meet up. "This, to me, says deliberate integration of Neanderthal individuals into human groups," Villanea said.

The cost of being hybrid

We know that some hybrid Neanderthal-H. sapiens survived because "we still carry the legacy of their existence," Alex said. However, we know they didn't thrive, because the Neanderthal ancestry of our ancestral populations eroded quickly.

Most genes work in concert with other genes across the genome. When Neanderthal-specific variants entered the modern-human genome, it was like trying to put gears from one machine into a slightly different one; the parts didn't quite fit together. As a result, natural selection removed the Neanderthal variants rapidly. Villanea's calculations, based on the rate at which chromosomes recombine during cell division, suggest the drop from the original approximately 5% Neanderthal DNA roughly 50,000 to 45,000 years ago to the roughly 2% carried today happened in around 10 human generations.

"That's very fast," he said. "In real-life terms, that means a lot of hybrids did not survive to reproduce, and the ones that did probably had to deal with life-long health problems."

Platt's team looked at genetic evidence from multiple sites across Eurasia and found that the genetic purge ran in the opposite direction, too. Modern-human DNA was also being selected out of Neanderthal genomes.

Neither had inherently superior genes, Platt concluded. The gene variants were simply optimized for the separate evolutionary histories of their respective lineages, hundreds of thousands of years of independent adaptation that made certain combinations disadvantageous, if not fatal.

Where the hybrids ended up

If Neanderthal males and modern-human females really were producing more surviving offspring than the reverse pairing, where did those children end up?

Villanea was cautious about reading too much into the X chromosome pattern on its own to answer that question. The imbalance Platt found is real, he said — not a statistical quirk. But "there is nothing in the X chromosome data that says it's based on human or Neanderthal mating preference," as Platt proposes.

The same pattern could, in theory, emerge from Neanderthal males leaving their birth groups to find mates, but as archaeological evidence suggests, this was not typical behavior. More likely, he argues, is something biological.

In Peromyscus maniculatus and Peromyscus polionotus — two closely related species of North American deer mouse — a phenomenon called genomic imprinting causes hybrid offspring to develop differently in the womb depending on which species was the father and which was the mother. This pattern has nothing to do with behavior or preference. A similar process in early humans could have made Neanderthal father-H. sapiens mother pairings more likely to produce surviving offspring than the reverse, without either group consciously choosing anything.

"We simply don't know enough yet," Villanea said.

Distinguishing between these explanations — social behavior versus biological incompatibility — will require more Neanderthal genomes from the critical period of contact, ideally spanning multiple geographic regions, experts said.

There's another clue in genetic evidence from a 2026 study of 27 late Neanderthals who lived between 50,000 and 40,000 years ago in what is now Belgium and France. None of those individuals showed any sign of recent ancestry from modern humans, even as H. sapiens from the same era demonstrably carried Neanderthal DNA.

If hybrid children had been raised in Neanderthal groups and went on to reproduce there, those groups' genomes should retain traces of those events ‪—‬ but they don't.

As for whether modern-human groups were patrilocal — with males staying, females moving — the answer is considerably more variable than in Neanderthals. Modern-human communities across cultures show a range of patterns, with both sexes leaving their birth groups depending on circumstance, Alex said. That flexibility may have been part of what made human groups better able to absorb outside individuals.

What we still don't know

Neither genetics nor archaeology has yet been able to answer the question at the center of this story: whether these encounters were by choice, by circumstance, or by force. Platt's team set it aside deliberately, and Alex is careful about it, too.

"We still wouldn't know if it was consensual or coerced," she said.

It's worth being specific about what different scenarios would look like archaeologically. If Neanderthal and modern-human individuals mingled through peaceful alliances, we might expect to find toolmaking techniques or symbolic objects crossing between groups at contact sites — precisely the kind of evidence that is absent at Grotte Mandrin, where, as Slimak noted, the two groups' technical traditions remained entirely distinct.

Slimak, writing from Grotte Mandrin in the middle of his excavation season, urged even more restraint. The genetic data, he said, are "consistent with an asymmetry" — gene flow moved more successfully through Neanderthal males and H. sapiens females than the reverse — but that is where the certainty ends.

The data says nothing about culture, desire, attraction or intent. "That entire social world has been added afterwards," he said.

The same signal, he pointed out, could emerge from a variety of histories — female mobility, demographic imbalance, alliance, exchange, capture, differential survival among hybrids. And these factors could contribute alone or in combination. Even the categories available for describing female movement may be too blunt. A single instance of migration, in traditional societies, can involve marriage, family strategy, alliance, obligation and violence all at once, in combinations that leave no trace for archaeology to disentangle.

"We may identify that a woman came from elsewhere," Slimak said. "We cannot recover her consent."

However, the convergence of genetics, demography and archaeology does reveal a structural picture, if not a sociological one.

The interbreeding was directional and repeated, patterned in ways that map onto the social organization of both groups — and driven in large part, Villanea's model suggests, by the sheer demographic weight of a growing human population folding in what remained of a disappearing one. Neanderthal males, in dwindling and insular communities, appear to have been the ones whose genes crossed into the larger H. sapiens world. Their children, in all likelihood, were raised as humans.

"Genes do not preserve past loves," Slimak said. "They preserve what was transmitted. And between transmission and lived experience lies almost the whole of human society."

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Scientists are getting a new glimpse of how the first galaxies came to be. In a stunning new simulation, researchers charted the aftermath of the universe's "dark age," including the appearance of the first galaxies that began to shine about 380,000 years after the Big Bang.

Lumina, the program behind the simulation, catalogs 2 billion years of cosmic time and represents a decent chunk of the 13.8 billion-year-old history of our universe. The results were published Monday (Oct. 26) in the journal Monthly Notices of the Royal Astronomical Society.

"Other simulations cannot zoom in as far as this," study co-author Mark Vogelsberger, a professor of physics at MIT, said in a statement. "The difference between the smallest and largest scales that we simulate is larger than in any other simulation."

A video published alongside the paper shows what the scientists saw. The team zoomed in on an area roughly 1.6 billion light-years wide to learn more about how the ingredients of space create galaxies.

Lighting up the Cosmic Dark Age

In the earliest years of our universe, a fog of neutral hydrogen atoms gradually built up, blocking out the light of the first stars. The hydrogen served as a "shroud" and didn't make light visible until galaxies began to form. This ancient, enshrouded period is known as the Cosmic Dark Age.

The video begins in the middle of this epoch, at roughly 45 million years after the Big Bang. Zooming in on one small part of the simulated universe, it slowly reveals a gassy halo giving way to young galaxies shining brightly within it. Included in the calculations are dark matter, stars, gas and radiation — all contributing to the reemergence of cosmic light.

"We see this is where the first galaxies form," first author Oliver Zier, a former postdoctoral researcher and computational astrophysicist at MIT who is now at Harvard University, said in the statement. "And the first stars form in those first galaxies. Those stars then create radiation. The simulation then tracks that radiation, and we can zoom way out to see how that radiation travels out from stars, through the universe, until at some point it ionizes some neutral hydrogen."

Lumina aims to show off two phenomena key to the young universe's history: hydrogen reionization and helium reionization — a first for a program of its kind. Reionization describes how the intergalactic medium, or the area between galaxies, changed from neutral hydrogen to negatively charged ions.

Hydrogen reionization took place when ultraviolet light from young stars and galaxies hit the hydrogen, removing negatively charged electrons from the hydrogen molecules — a process that also allowed light to shine through the fog. Helium reionization happened when supermassive black holes, which have a lot of energy, broke apart neutral helium molecules.

The team said the simulation could eventually be used to validate telescope observations of the early universe, especially those focused on mapping many galaxies at the same time.

Colorectal cancer rates have been rising in people under 50 since the mid-1990s. These early-onset cancers tend to be more aggressive and resistant to treatment than cancers in older adults — and now, scientists may be learning why.

A new study published Thursday (Oct. 29) in the journal Nature Medicine compared colorectal tumors from people between 29 and over 90 years old, and it revealed key differences between young and old patients.

The new findings might, in turn, help scientists uncover new ways to fight colorectal cancer in young people, said study co-author Ana Anderson, a professor of neurology at Harvard Medical School and a core faculty member of the Gene Lay Institute of Immunology and Inflammation at Brigham and Women's Hospital.

"I believe that our study is essentially a turning point now in the field," Anderson told Live Science. "Because up until now, we've had more questions than answers."

Many questions surround early-onset colorectal cancer, as the disease is rising in people under 50 even as it falls in older populations. It's now the leading cause of cancer death in the U.S. for people under 50, and its numbers are even on the rise among children and adolescents.

Beyond questions about what's driving this uptick in cases, another mystery has been why this disease is so deadly in young people.

"The clinical data suggests that the disease in the younger patients is more aggressive overall," Anderson said. "The patients, being very healthy otherwise, do not do well with treatment."

To investigate that mystery, Anderson collaborated with Dr. Kimmie Ng, an oncologist at the Dana-Farber Cancer Institute, and Dr. Ramnik Xavier, a gastroenterologist at the Broad Institute and Mass General Brigham. They used a method of analyzing RNA in cells that allowed them to work with frozen and banked tumor tissue. RNA, a cousin of DNA, reflects the genes that are active in cells. In all, the team analyzed 189 tumors: 54 from patients under 50 and 135 from patients over 50.

With that many samples, the researchers could look at gradual differences tied to each age group, instead of just comparing tumors between the younger and older groups overall. That enabled them to pinpoint subtle differences, Anderson said.

For starters, younger people had a higher proportion of connective tissue cells in their tumors than they did of malignant cancer cells. That pattern was flipped in patients of older ages. Having a smaller proportion of malignant cells might sound good, but connective tissue in tumors can secrete compounds that suppress the immune system, Anderson said. That helps protect the tumor from immune cells that might otherwise target its cells for destruction.

These connective tissue cells can also physically block chemotherapy drugs from getting to the cancerous cells. This could be one reason younger patients' cancers resist treatment, the researchers suggested.

Based on patterns of gene activity in the tumors, the researchers suspect that younger patients' cancer cells also show distinct activity related to cell-to-cell communication. That may help the cells migrate through the body more easily than cancer cells in older patients do. In other cancers, this kind of gene activity has been linked to more aggressive tumors and a greater chance that the disease will spread, or metastasize, Anderson said.

The study's results also turned up an intriguing mystery: the presence of lots of long noncoding RNA. These strands of RNA contain more than 200 building blocks, called nucleotides, that don't provide instructions for building proteins. Coding RNA, in contrast, is ferried to protein-building factories in cells to be used as blueprints.

Scientists don't know what much of this long noncoding RNA does in the body, nor do they understand what it is doing in the tumors specifically. However, they hope to find out.

Anderson and her team are already working on manipulating the RNA they found inside cancer cells in petri dishes. In time, this line of research could supply another piece of the puzzle, helping scientists understand why colorectal cancer is so aggressive in young people.

"It's a new avenue for research into this disease that we previously had no idea about," Anderson said.

This article is for informational purposes only and is not meant to offer medical advice

Archaeologists have recovered a well-preserved bronze sword from a volcanic lake in Italy. The 3,300-year-old weapon may have been deposited in the lake as an offering to a deity or for a high-status warrior who lived long before the rise of the Etruscans or the Romans.

The sword was found in Lake Mezzano, which is located in the crater of an ancient volcano roughly 60 miles (100 kilometers) northwest of Rome, according to a translated statement from the Superintendence of Archaeology, Fine Arts and Landscape for the Province of Viterbo and Southern Etruria. Dating to the Late Bronze Age (14th to 13th centuries B.C.), the sword has maintained its sharp edge. It is the third such sword found in Lake Mezzano in the past 50 years.

Bronze Age people erected pile dwellings or stilt houses in what is now Lake Mezzano, and archaeologists recovered parts of the submerged settlement during their recent investigations. According to the statement, researchers also found numerous intact vases, axes, arrowheads, daggers, spearheads, pins and a bronze razor.

The sword and the razor were found near each other, suggesting the two artifacts may have been linked to a person of high social status, such as an elite warrior. But the placement of the metal weapons in a lake may also be related to a wider Bronze Age ritual practice where hoards of jewelry and bent or ritually "killed" artifacts were tossed into bodies of water. This practice continued through the centuries into Etruscan times, when wells were ritually "closed" with artifacts and human sacrifices.

During the 13th century B.C., people in central Italy engaged in trade networks that spanned the Mediterranean. "In this context, bronze weapons were not only instruments of combat, but also symbols of prestige, identity, and power," according to the statement.

The sword and other artifacts discovered in Lake Mezzano are giving archaeologists new information about the people who flourished in prehistoric Italy long before the Romans and Etruscans. Additional research is planned in the coming years, according to the statement.

Can you identify these historical objects of war? Test your smarts with our weapons of the world quiz!

A new U.S. intelligence agency report has seemingly released the first clear photograph of China's mysterious "dragon" space plane in orbit around Earth. The surprise snap reveals that the top-secret vehicle is very similar to its American counterpart and provides new clues about its capabilities.

The image is widely believed to show China's secretive Shenlong, or "divine dragon," space plane, which has been in action for just over six years. During this time, the reusable winged spacecraft has repeatedly made headlines after deploying various unidentified objects in low Earth orbit (LEO). As a result, government officials, private companies and individual researchers have closely monitored the vehicle using tools such as ground-based radar.

Until now, the only direct images of the space plane have been blurry snaps of light reflecting off the uncrewed vehicle toward Earth's surface — offering no clear clues to its specific design, capabilities or intended purpose. China has also never publicly shared any photos of the vehicle or revealed any key information about its design.

On Monday (Oct. 26), the Defense Intelligence Agency (DIA) released the latest version of its "Challenges to Security in Space" report, which assesses the various factors that pose a risk to American space assets. Deep within the 130-page document (on page 53), the authors included a previously unseen image of a "PRC [People's Republic of China] Spaceplane." The image's brief caption revealed that the photo had been taken in 2024 by a satellite belonging to the private space company Maxar Technologies, now known as Vantor.

The surprise inclusion of the photo was spotted and shared on the social platform X by journalist Andrew Jones, who specializes in China's space program and has previously shared crucial information about other ongoing missions.

Neither the caption nor the related section of the report made any mention of the photo being the first of its kind or explained why it was previously classified, raising questions about whether the authors realized its significance.

There is one small caveat. The report notes that China has two active space plane designs — Shenlong and Tengyun, meaning "cloud rider" — and the image's caption does not specify which design we are looking at, according to The Aviationist.

However, there have been no confirmed launches of Tengyun to date. Existing photos of a potential prototype also hint that this vehicle's design looks markedly different from what we can see in the new photo. Therefore, most experts agree that the spacecraft in the image is most likely Shenlong.

What does the new photo tell us?

Until now, all we really knew about Shenlong is that it operates similarly to NASA's iconic space shuttles: It gets launched into space by a rocket and circles Earth before eventually gliding down to the planet's surface, where it can then be refueled and relaunched into LEO.

It is not the world's only active space plane. The U.S. Space Force has its own, the X-37B, which has already completed seven orbital missions since its first launch in 2010 and is currently in LEO experimenting with quantum navigation. Based on the new photos, Shenlong shares many similarities with its American counterpart.

"The Chinese spaceplane has delta wings, payload bay doors, a dark heat shield, and a rear-mounted service module with power-generating solar arrays," technology news site ArsTechnica reported. "In other words, the design of the winged ship is, to a great degree, a copy of the X-37B spaceplane flown by the U.S. Space Force."

However, the two spacecraft are not exactly the same: "The overall arrangement resembles the American vehicle, although differences in wing geometry show that the two spacecraft are not externally identical," according to specialist news site Global Defense News.

It is still unclear how large Shenlong is. The X-37B is 29 feet (8.8 meters) long and has a wingspan of 15 feet (4.5 m), according to Popular Science.

The new image also indicates that Shenlong is most likely not a military asset, Global Defense News reported, noting that "the image does not establish a weapons role."

However, China likely has other space-based weapons, similar to the mysterious "in-orbit" American weapons recently confirmed by U.S. Air Force Secretary Troy E. Meink.

"China has developed and will continue to advance weapons for use against satellites in orbit to disrupt, damage, and destroy other nations' space capabilities," DIA representatives wrote in a separate section of the new report. "Beijing aims to become the preeminent leader in space," they added.

The Shenlong story so far

Since first launching into space on an initial two-day mission in September 2020, Shenlong has completed two feature-length missions: an eight-month stint in LEO between August 2022 and May 2023, and a nine-month spaceflight between December 2023 and September 2024. (The new image was taken during the latter mission).

The space plane is currently on its fourth mission, which launched Feb. 7 on board a Long March 2F rocket from China's Jiuquan Satellite Launch Center, Live Science's sister site Space.com previously reported. In total, Shenlong has racked up more than 800 days in orbit. However, it is unclear whether the same space plane was used on all four missions or if China has more than one space plane in use.

So far, Shelong has released at least nine unidentified payloads around Earth. These objects are most likely small satellites, known as cubesats, but their purpose remains unclear.

The most recent object was deployed in June this year, although astronomer Jonathan McDowell, who specializes in tracking spacecraft in LEO, has since suggested that the spacecraft retrieved the object, potentially with a robotic arm, and rereleased it in late August.

The new report also mentions that the space plane "appeared to maneuver with a companion satellite" during its second mission in November 2022, coming within 330 feet (100 m) of the smaller spacecraft and potentially even capturing and re-releasing it.

This may support an existing theory that the main goal of Shenlong is to "conduct rendezvous and proximity operations" with other spacecraft, and that its payloads may be targets for it to practice flyby maneuvers in orbit.

Editor's note: This article was updated on Oct. 29 to correct a typo. A previous version of the article abbreviated the People's Republic of China as "PCR" rather than "PRC". This has been corrected.

People with inflammatory bowel disease (IBD) experience gut pain that can be severe, and it doesn't always go away when their inflammation is under control and their colonoscopy looks normal. Now, in a new laboratory study, researchers found a previously unknown pain pathway that may explain this phenomenon.

The findings, published Oct. 23 in the journal Science Immunology, also point to a potential way to block that pain.

"Inflammation in the gut has always been thought of like a fire: the sensory nerves alarm because of the smoke and the heat, and when the fire is put out the alarm should stop," said study co-author Dr. Heng Xu, a physician at Ninth People's Hospital in Shanghai. Xu and his colleagues set out to try to isolate what could be causing the pain even when there's no visible "fire" or "smoke."

"What we found is that the tissue itself changes consistency," Xu told Live Science in an email. "It becomes stiff and less elastic, a bit like a scar, and that stiffness alone keeps triggering the alarm even after the fire is out."

In ulcerative colitis, the most common form of IBD, inflammation causes ulcers in the gut, as well as symptoms like bloody diarrhea and abdominal cramping. Several medications can help quell this inflammation, but that doesn't necessarily eliminate patients' pain. The researchers wondered if immune cells that live in the gut might contribute to that ongoing pain.

They zoomed in on a protein called Piezo1; in immune cells, it's known to play a role in inflammation, and in neurons, it contributes to pain signals. The team looked at whether this protein's activity changed in the context of colitis.

"We started with sequencing data that reads cells one at a time, from the gut tissue of patients with ulcerative colitis and from mice with the disease," Xu said. "One cell type stood out: an immune cell that lives permanently in the gut wall, rather than arriving from the bloodstream when there's trouble." The quantity of these cells was higher in colitis than in healthy guts, and the cells carried more Piezo1 than the other cells analyzed.

"They sit touching the nerve endings," Xu added.

In several experiments with lab mice with colitis, the team used a probe to press on the gut tissue and measure how hard it was. This showed that, compared with healthy mice, the gut was stiffer in two models of disease: one with visible inflammation and another with almost none.

They also measured pain levels in both sets of mice. "In mice with almost no visible gut inflammation, the pain was still there, which is why a colonoscopy can look normal while the patient hurts," Xu said.

They then looked at Piezo1 in both sets of mice. The protein sits in the immune-cell membrane, and when the stiffened tissue around it is pulled or squeezed, it's as if a button were pressed and a channel opens, Xu said. This sets off a chain reaction that leads to pain, Xu said.

That's because calcium ions rush into the cell via the channel, and that surge sends a protein called NF-kB from the cell's interior fluid into its nucleus — the control center where DNA is stored. There, NF-kB plugs into a gene, ordering the cell to manufacture nerve growth factor (NGF) that then exits the immune cell.

This NGF, which is known to amplify pain signals in the body, interacts with nearby pain-sensing neurons. These nerve endings grow denser and become hypersensitive, which makes ordinary gut activity painful, the study suggests.

The researchers used chemicals as on-off switches for Piezo1 in immune cells, opening the channel with one and closing it with another. As they did this, they tracked calcium signals and NGF production, and both rose and fell in step with the switch. This result suggests that Piezo1 activity is both necessary for this response and, on its own, enough to trigger it in these cells, Xu said.

Blocking this chain of events abolished the pain hypersensitivity in both sets of mice. The researchers tried completely removing the Piezo1 gene from the gut immune cells and found that this eliminated the pain. Removing the gene also caused no problems in healthy mice, they noted.

The study was "well controlled," said Hongzhen Hu, the scientific director for the Mark Lebwohl Center for Neuroinflammation and Sensation at the Icahn School of Medicine at Mount Sinai, who was not involved in the research. Future research should address the chemical messengers that coordinate inflammation, called cytokines, and determine whether the same chain reaction occurs in human cells, he said in an email.

The mouse experiments also may not reflect long-term, chronic disease in patients, given the mice experienced symptoms only transiently, Xu said.

Xu and his colleagues are now aiming to develop a drug that can target Piezo1 to switch off gut pain locally without suppressing the entire immune system. This would be a more targeted treatment than current options, such as immunosuppressants or opioids.

Other scientists have explored using anti-NGF treatments for other chronic pain conditions but not for ulcerative colitis, Xu noted. Fully blocking NGF might have downsides, he said, since NGF also helps to maintain nerves.

So more work is needed to translate these findings into a treatment. But for now, the work sheds new light on how immune cells can detect a physical change — such as tissue becoming stiff — and convert it to a pain signal.

"For the pain field, that's a conceptual shift," Xu said.

This article is for informational purposes only and is not meant to offer medical advice.

The enigmatic and now-extinct Denisovans of China shared traits with Neanderthals, modern humans and Homo erectus, according to a new study that looked at ancient proteins and fossils. But the Denisovans also had several unique skull traits and genetic variants that made them a distinctive ancient human group, according to the researchers ‪—‬ and these traits have now revealed a new face for a Denisovan man.

In the study, published Oct. 21 in the journal Nature, researchers analyzed Denisovan skulls from the archaeological site of Xujiayao in northern China. The Denisovans were a group of ancient humans who lived in Asia and disappeared around 30,000 years ago. This human relative was first identified in 2010 from the DNA of a finger bone discovered in a cave in Siberia.

The Xujiayao bones and teeth were excavated in the late 1970s, long before scientists knew about the existence of Denisovans, and were initially thought to be either Neanderthals or archaic Homo sapiens due to the shape of the fossils and their age: 138,000 to 199,000 years old.

But recent advances in paleoproteomics ‪—‬ the study of bone and tooth proteins that persist longer than DNA ‪—‬ have helped researchers identify Denisovan individuals due to specific genetic variants that differentiate them from other ancient human groups.

In the new study, researchers used paleoproteomic analysis on 20 remains from Xujaiyao and determined that all of them were from Denisovans. This determination then allowed the researchers to study the skull bones closely and figure out what Denisovans might have looked like.

The Xujiayao skulls had some features similar to H. erectus, the researchers wrote, including a low and wide braincase and thick cranial bones. But they also had anatomical features more similar to those of Neanderthals and modern humans, particularly in their bicuspids (the teeth between the canines and molars). The researchers also identified some unique Denisovan cranial traits. The back of the skull, for example, was more vertical and less rounded than in Neanderthals or modern humans.

Armed with a better understanding of Denisovan skull shape from the Xujiayao fossils, the researchers compared them with East Asian Denisovan remains that some experts have assigned to other species, such as Homo juluensis and Homo longi. But the researchers identified similarities that may preclude splitting Denisovans into different species.

"This unique combination of morphological traits, distinct from H. erectus, modern humans and Neanderthal-lineage hominins, supports the assignment of most members of East Asian late Middle Pleistocene archaic Homo as Denisovans," they wrote in the study. This means that Denisovans may have been one human lineage that adapted to diverse ecological zones across Asia over hundreds of thousands of years.

"It is still possible that there are some other lineages that existed in East Asia during the time Denisovans are known to have existed," study co-author Qiaomei Fu, director of the Ancient DNA Laboratory at the Institute of Vertebrate Paleontology and Paleoanthropology, part of the Chinese Academy of Sciences, told Live Science in an email.

"We know from DNA that Denisovans were a very varied group genetically, which split early into different populations," Chris Stringer, a paleoanthropologist at the Natural History Museum in London who was not involved in the research, told Live Science in an email. "These could have developed a lot of morphological variation, which may well surprise us as the sample of fossils grows."

The researchers also produced a new reconstruction of what a Denisovan man might have looked like. A previous DNA study suggested that Denisovans likely had dark skin, brown hair and brown eyes. The new reconstruction shows the Denisovan looking directly at the viewer, with his low, wide braincase mostly obscured by dark hair flowing back from his massive brow ridge. There are clear similarities between the Denisovan man and Neanderthals as well as modern humans, but the Denisovan has a distinct visage all his own.

See how much you know about early humans with our human evolution quiz!

The patient: A 42-year-old woman in Somaliland, Africa

The symptoms: The woman went to the hospital after having three years of chronic, dull pain in her lower abdomen, as well as a growing sense of heaviness in her abdomen that had worsened in recent months.

When doctors reviewed her medical history, they learned that, three years earlier, she had experienced a number of symptoms that seemed to indicate a pregnancy. She recalled her abdomen growing over time and feeling "fetal movements," her doctors noted in a report of the case. Then, the movements stopped, the abdominal growth halted, and the enlargement gradually subsided. She had not sought medical care during or after this apparent pregnancy.

What happened next: When doctors physically examined the woman's abdomen, they found a hard, irregular mass that extended to her belly button and barely moved when they touched it. Blood tests showed mild anemia, meaning she had fewer healthy red blood cells than normal. Her white blood cell count and kidney and liver tests were normal, and a pregnancy test was negative.

An ultrasound revealed a calcified mass and an empty uterus. Calcification is a buildup of calcium that hardens tissue into a solid mass.

To get a better look at the mass, which occupied the woman's lower abdomen and pelvis, the doctors ordered an advanced CT scan to create a 3D model. The imaging revealed that the mass contained clearly identifiable fetal skeletal structures, including a skull, a spinal column, ribs, and arm and leg bones. The mass measured roughly 7 by 5 inches (18 by 13 centimeters).

The diagnosis: Doctors concluded that the woman had a lithopedion, or "stone baby." The term comes from the Greek words "lithos," meaning stone, and "paidion," meaning child.

In a typical pregnancy, an egg is fertilized in a fallopian tube — the structure between the ovaries and the womb — and then travels into the uterus, where it implants in the uterine lining. By contrast, lithopedions most often start as abdominal pregnancies,‬ a type of ectopic pregnancy in which the embryo instead implants on the lining of the abdominal cavity.

There, the embryo shares the space with organs like the stomach, kidneys and appendix. These misplaced pregnancies are almost never viable and are highly life-threatening for the mother. Because the placenta attaches directly to delicate abdominal organs and blood vessels, these carry a severe risk of catastrophic internal bleeding.

If the fetus dies at a developmental stage when it is too large for the mother's body to naturally break down and absorb, her immune system can sometimes treat the retained tissue as a foreign object. To protect the mother from inflammatory complications and infection, the body progressively deposits calcium over the fetal remains, creating a protective casing. In this case, the calcified fetus likely accounted for the woman's chronic abdominal pain and increasing sense of heaviness, her doctors concluded.

The treatment: The doctors performed abdominal surgery to completely remove the calcified fetal mass from the woman's pelvis.

The day after surgery, she developed a mild fever and nausea, but both resolved with treatment. She remained stable and improved during her hospital stay before being discharged in good condition.

Follow-up visits over the next six months showed she had healed well, with a complete resolution of her abdominal pain.

What makes this case unique: Only about 340 cases of lithopedion have been documented in the medical literature over the past 400 years, with the earliest documented in 1582.

This woman's case stands out because she was 42 years old, while many recent cases have been diagnosed in postmenopausal women. (Women typically experience menopause around 51 to 52 years old.) In these cases, the initial ectopic pregnancy occurred during the woman's childbearing years, but she unknowingly carried the calcified remains for decades before developing symptoms. For example, a 74-year old woman from India carried her "stone baby" for more than three decades. By contrast, the woman's recent case was caught after only three years.

The case also highlights the challenges of maternal healthcare in resource-limited settings such as Somaliland, where a lack of access to routine prenatal care and early pregnancy scans can lead to delayed diagnoses. That said, the successful use of advanced 3D imaging and complete surgical recovery demonstrate that excellent outcomes are possible even in these constrained environments, the doctors noted.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

Can you guess the diagnosis in these strange medical cases? Find out with our diagnostic dilemma quiz!

Universities are at a critical point as students and faculty embrace the use of AI. Already, universities like Harvard are introducing courses that feature an AI avatar as an "instructor."

The promises AI offers higher education are familiar: an increase in efficiency as a consequence of less administration, more teaching coverage, better feedback and smarter assessment. But introducing artificial intelligence (AI) systems in an attempt to fix these problems is not the answer. If anything, AI systems will magnify and speed up the bureaucracy that is driving universities' decline.

In practice, the more likely outcome is darker: AI will not simply sweep away the bureaucratic machinery of universities; it will give that machinery a new regime of AI compliance — more policies, more forms, more trackers, more oversight roles and more work downloaded onto faculty who are already stretched thin.

The danger is not that AI will destroy universities but that universities will use AI to preserve the very processes that make them dysfunctional. If this happens, we might see faculty spending less time on research, less time on teaching, and more time on activities that do not directly contribute to the production of knowledge and education of students.

This is already evident in the existing assessment system in the U.K., but shades are creeping into systems elsewhere, providing a window into the future for U.S institutions. A single piece of student work may pass through a plagiarism-detection platform, a grading interface, a moderation spreadsheet for faculty to share feedback, a grade-transfer system, and an exam-board record. Each stage generates its own logins, deadlines, exception rules and audit trails. None of this is inherently malicious. Anonymous marking, moderation, appeals, accessibility and academic integrity are legitimate concerns. But when each concern is implemented as a separate system, the combined effect is administrative incoherence.

In essence, faculty become the human interface between incompatible platforms, spending their time reconciling grades and chasing missing evidence rather than teaching. While this example pertains to U.K. universities, the trend to expand the administrative staff extends to North America. AI simply introduces a new opportunity to increase administration.

AI could, in principle, solve this. It could integrate systems, automate routine reporting, draft feedback, identify inconsistencies and remove duplicate data entry. Yet the institutional incentive is rarely to remove work; it is to make work visible. A university that automates a broken workflow does not necessarily simplify it. It may simply produce faster reports about the broken workflow, more sophisticated dashboards and more elaborate evidence of compliance. The bureaucratic impulse survives by changing its vocabulary: risk management, assurance, transparency, governance, responsible innovation.

At least one possible outcome is that universities will create AI-use policies, require module-level AI statements, mandate disclosure forms, introduce approved-tool lists and establish review committees. Faculty will be asked to redesign assessments, monitor suspected misuse, document their decisions, complete training, and explain their approach to students. Much of this labor will be invisible. It will appear not as a new job title but as an additional expectation attached to teaching.

This creates a familiar pattern: responsibility without authority. Faculty are expected to make consequential judgments about academic integrity, fairness, privacy and assessment validity. But they do not control procurement, system design, institutional policy or disciplinary procedures. When something goes wrong, the academic is exposed; when the system works, the institution claims the credit.

That asymmetry is corrosive. It teaches committed staff that careful judgment is not valued as expertise but rather as a compliance risk to be managed, and the consequences will fall unevenly. Experienced faculty, after voicing their concern to no avail, may leave, retire early or disengage. Early-career academics, already precarious because they don't have tenure, will have the least power to resist. Students will receive less of the resource that matters most: sustained intellectual attention.

One possible outcome is that universities will encourage the development of faculty AI avatars and cut hours and employment. The institution will then justify hiring more ‪—‬ not fewer ‪—‬ compliance and "educational enhancement" staff to manage and maintain these AI avatars, negating the idea of efficiency and cost savings. In this scenario, bureaucracy will expand to manage the problems created by its own expansion while undercutting quality for the students who are paying high tuition fees. One might need to hire staff for oversight of these avatars, administrators and lawyers to manage licensing agreements, quality control staff in case things go wrong, and IT teams for integrating them into learning platforms and websites.

There is an alternative to the administrative tasks. AI should be governed by a simple institutional rule: no new compliance requirement without the removal of an equivalent existing burden. If a university requires assessment redesign to accommodate AI, or the introduction of new technology, it should provide protected time, technical support and a single integrated platform. If it expects faculty to manage AI use, it must give them clear institutional backing rather than leaving them to improvise. And critically, it should show how the technology makes work more efficient before rolling it out across the board.

But the deeper issue is not technology but institutional purpose. A university exists — or should exist — to cultivate understanding, judgment and intellectual independence. If its systems consume faculty time, fragment the student experience, and reward documentation over learning, then AI becomes another instrument of managerial self-preservation. The question is not whether universities can adopt AI. It is whether they can resist using AI to automate their own absurdities.

If they cannot, the outcome will be an educational system that looks progressively sophisticated while becoming increasingly hollow ‪—‬ full of monitoring, low on trust; rich in measuring, poor in teaching; obsessed with compliance, indifferent to the people who make education possible; overly procedural sans intellectual life. It will become an audited theater of learning not worth students' time.

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Artificial intelligence (AI) tools like chatbots are becoming part of everyday life, helping people write messages, answer questions and learn new skills. While some of these processes may save people time, a new study reveals a possible new downside of consistently relying on AI assistance.

The research, presented at the 2026 Conference on Language Modeling in San Francisco earlier this month, found that people who relied on AI assistance for tasks like math problems and reading comprehension were more likely to give up or struggle when the assistance was taken away. The findings suggest that leaning too heavily on AI could weaken people's motivation to push through challenges.

The research raises the question of what happens when people stop exercising their brains. So do you think AI is making you less motivated, or even "dumber," or is it simply making you more efficient? Vote in our poll, and let us know your thoughts in the comments.

A male tiger approaches his cubs and greets them with a head-bobbing motion while their mother rests nearby. The surprising interaction, captured in the PBS Nature documentary "Tiger Island," a two-part series that follows two big-cat families across Nepal.

The footage marks the first time a tiger "family" has been documented spending time together, and it could challenge conventional assumptions about how the seemingly solitary cats behave around their young, said Dan O'Neill, a wildlife biologist and filmmaker who contributed to "Tiger Island." Previously, it was thought that tiger moms raise their cubs for up to two years without any help from the male tiger.

But this may not be the norm.

"It just shows that we really know nothing about them," O'Neill told Live Science. "And they're so much more complex than people realize."

That's just one of the scenes in Tiger Island that challenges our understanding of the tigers' solitary nature. In another scene, a female tiger cares for another tigress's cubs.

"We have these very rigid ideas of how these animals live," O'Neill told Live Science. But the natural world is "diverse and ever-changing," and tigers are no exception, he said.

The footage of the female caring for another tiger's cubs could offer clues about how mother tigers protect their young. Male tigers, like male lions, sometimes kill cubs ‪—‬ a behavior known as infanticide ‪—‬ particularly when a new male takes over a territory. Allowing another female tiger to care for cubs might help more cubs survive to adulthood, O'Neill suggested. Previous observations of female tigers have shown females helping to co-parent each other's cubs, but it's a rare event.

To capture these scenes, the crew used drones with powerful optical-zoom lenses and quiet propellers to observe the tigers in places that were difficult to access without disturbing the big cats. Traditional camera traps often capture animals along trails, leaving much of their private lives unseen. O'Neill noted that the drone propellers were quieter than the local bees where the filming took place, thus giving the crew candid views of the tigers as they went about their lives.

Solitary animals in urban jungles

Though tigers (Panthera tigris) are solitary animals, they often live close to or share habitat with human communities. That means tigers sometimes attack people and kill livestock, O'Neill said. "It would be absolutely naive and wrong to suggest that they [attacks on people] don't happen," O'Neill said. As a result, conservation efforts must account for the circumstances in which people and big cats encounter one another, rather than treating human communities as separate from wildlife, he said.

The same issue affects other big cats. O'Neill, a researcher with the wild-cat conservation organization Panthera, has spent years studying jaguars, pumas and snow leopards. He said the popular image of these animals living in remote wilderness can obscure how closely they overlap with human lives.

For O'Neill, conservation requires more than studying the animals' behaviors or protecting their habitats. It also means helping people who bear the cost of living alongside these apex predators.

"Helping those people is how you help tiger conservation," he said.

In the U.S. "Tiger Island" Part Two airs on Wednesday, Oct. 28 at 12:30 am on the PBS channel.

Think you know about lions and tigers? Test your smarts with our big cat quiz!

Scientists have sequenced the genomes of three Late Stone Age people who lived in Europe 30,000 years ago and discovered that they had closer biological ties than researchers previously thought. The new finding suggests that places like southwestern France may have been critical cultural hubs during the last ice age.

Shortly after Neanderthals disappeared from Europe, a Stone Age culture known as the Gravettian spread across the continent. Artifacts found during archaeological excavations ‪—‬ including portable art, such as "Venus figurines" ‪—‬ have shown that the Gravettian culture lasted from about 34,000 to 25,000 years ago. But ancient DNA has been recovered from only two dozen human skeletons from the Gravettian period, so questions about these people's ancestry remain unanswered.

Based on the small number of genomes from Gravettian people that were previously sequenced, experts believed that groups in Western Europe were largely separate from groups in Eastern Europe. But in a study published Oct. 23 in the journal Science Advances, researchers sequenced the genomes of three people who lived in what are now Spain, France and Italy during the Gravettian period. They discovered that one person had mixed genetic ancestry that revealed East-West exchange at least 30,000 years ago.

"Our results show that eastern and western European populations were not as genetically isolated as previously assumed," study first author Pere Gelabert, an evolutionary anthropologist at the University of Vienna, said in a statement.

The new information about mixed ancestry comes from a woman who died around 30,000 years ago and whose bones were found in Isturitz Cave in southwestern France. Originally used by Neanderthals, Isturitz Cave was occupied off and on from about 80,000 to 10,000 years ago. Cups made out of human skulls dated to roughly 15,000 to 12,000 years ago have also been found in Isturitz Cave.

Researchers found that the DNA from the Gravettian woman in Isturitz Cave was most similar to the previously known Western European genomes, but with an intriguing connection to Eastern and Central European groups.

This discovery of gene flow from the East is uncommon for the Late Stone Age, also known as the Upper Paleolithic, the researchers wrote in the study. It "could be explained by movements of people from Eastern Europe during the Gravettian period, which eventually contributed to this ancestry in Isturitz." Specifically, the researchers dated this "pulse" of gene flow to about 31,500 to 32,500 years ago.

The DNA evidence supports the archaeological theory that Isturitz Cave was an important cultural and biological hub for tens of thousands of years during the Late Stone Age, as the cave was located at a critical passage between continental Europe and the Iberian Peninsula, the researchers wrote.

All three newly sequenced Gravettian genomes revealed close biological connections to Western European groups, as well as genetic traits suggesting they had dark skin, dark hair and dark eyes. What's more, all of them had parents who weren't closely related to each other, suggesting that those populations may have actively avoided inbreeding.

"Overall, our results suggest that population structure and gene flow in western Europe during the Gravettian were more complex and dynamic than previously assumed," the researchers wrote.

See how much you know about early humans with our human evolution quiz!

A proposed change to decades-old guidance on hepatitis B vaccination would lead to a dramatic increase in chronic hepatitis B virus (HBV) infections among young people, a new modeling study predicts.

Previously, the Centers for Disease Control and Prevention (CDC) recommended that all newborns be vaccinated against HBV within hours of birth ‪—‬ a strategy known as "universal birth-dose vaccination." But in December 2025, the Advisory Committee on Immunization Practices (ACIP) advised ending this recommendation, and the CDC accepted that advice.

The new guidance would recommend birth doses only to babies whose mothers tested positive for HBV or whose HBV status was unknown. The guidance suggests that mothers who test negative should instead ask their doctors about whether their child needs a birth dose — an approach the CDC calls "shared clinical decision-making." The new recommendation states that babies who forgo the birth dose should be at least 2 months old before starting the HBV vaccine series.

Health experts widely criticized the proposed change when it was announced, and for the moment, its implementation has been put on pause by legal action. The modeling study, published Oct. 19 in the journal Annals of Internal Medicine, predicts what would happen if it came to pass.

"Overall, this modeling study has many strengths and I think presents an accurate projection of how the vaccine recommendations may impact future chronic HBV in the U.S.," Dr. Norah Terrault, a transplant hepatologist at the University of Southern California Keck School of Medicine who wasn't involved in the study, told Live Science in an email.

When caught in infancy or early childhood, over 90% of HBV infections become chronic. About 15% to 25% of people with chronic HBV go on to develop liver scarring (cirrhosis), a form of liver cancer called hepatocellular carcinoma, or another chronic liver disease. So, an uptick in chronic HBV infections would translate to an uptick in these harmful liver conditions.

Increases in infection

"Not every pregnant person is tested for hepatitis B," said study co-author Dr. Amir Mohareb, an infectious-diseases physician-investigator at Massachusetts General Hospital and Harvard Medical School. For those who are tested, there's a chance their results are inaccurate or that they're not provided the right care after testing positive. "Something can be missed at any step in the care process, so the vaccine dose at birth provides protection," he said.

Mohareb and his colleagues built a simulation model using published data, including the current prevalence of HBV and the screening rate among pregnant people. The team also factored in the HBV test's sensitivity, the share of children who are fully vaccinated by age 2, and the risk of developing chronic HBV infection in different age groups. They made estimates of how often children are exposed to the virus through contact with infected household or community members.

HBV is "very, very transmissible," Mohareb said. It can spread from mother to child at birth or through exposure to tiny amounts of bodily fluids, like blood from a scratch, after birth. So, even if a baby does not get HBV from their mother, if they are unvaccinated, they can still get from another family member or from other children.

With this data, the researchers tested what would happen if vaccination were postponed to 2 months of age for babies whose mothers tested negative. Among babies born in 2026, 19% more would have chronic HBV infections by age 20, compared with universal birth-dose vaccination, they found.

In this scenario, the babies would still start the HBV vaccine series, albeit two months later than usual. However, the CDC's proposed recommendation offers more wiggle room; it says that parents should consult with their children's doctors to "decide when or if their child will begin the hepatitis B vaccine series" at all.

The researchers ran a stimulation to compare these two scenarios: one where kids get their first shot two months late and one intended to capture this looser "shared clinical decision-making" scenario.

"Other vaccines whose recommendations employ similar language had uptake as low as 25%," Mohareb noted. This aspect of their modeling has some uncertainty, he emphasized, since it's unknown exactly how the public will respond to such loosening of the guidance.

The researchers assumed that about 87% of kids would complete the vaccine series by age 2 under the deferred strategy, while only 50% would under the shared decision-making strategy. That 50% coverage, in turn, would increase chronic HBV infections acquired by age 20 by 83%, and about 50% and 70% of those born under that guidance would be susceptible to HBV infection at age 20.

That's about 1.8 million people in this age group per year, compared with fewer than 250,000 under universal birth-dose vaccination. "This represents a population that is at risk for acquiring HBV via sex, drug use etc — behaviors more prevalent among young adults," Terrault said.

A "missed opportunity to protect against infection"

To test the robustness of the findings, Mohareb's team varied the most uncertain inputs across wide ranges and ran the model 1,000 times. In every simulation, the birth-dose strategy led to fewer chronic infections than either alternative.

These conclusions seem "robust" because "they are the same conclusions no matter how we change the numbers of the model," Mohereb noted. Though of course "the specific magnitude of change depends on how many people defer vaccination," he said.

The new study does not specifically show how many additional cases of liver disease or cancer would result from the uptick in HBV infections. But Terrault said that the risks of liver failure, cirrhosis and liver cancer "would be anticipated to increase due to the missed opportunity to protect against infection."

Mohareb stressed that he is in no way opposed to the principle of shared decision-making between doctors and patients. "They should always make the decision together," he said. "But we rely on our public health agencies not to tell us that we should be making decisions with the patient, but rather to tell us what policy would make us healthier as a country."

Childhood HBV infections in the U.S. dropped from more than 25,000 cases a year in 1985 to fewer than 100 reported cases in 2024. This steep decline is credited to HBV screening during pregnancy, antibody treatment for babies born to HBV-positive mothers and universal birth-dose vaccination.

"Certainly without following a universal dose vaccination recommendation there would be a lot more hep B infections early in life," Dr. Brian McMahon, a hepatologist and the director of the Liver Disease and Hepatitis Program at the Alaska Native Medical Center, told Live Science in an email.

This article is for informational purposes only and is not meant to offer medical advice.

Native Hawaiians and Easter Islanders genetically descend from the same "ultravoyager" Polynesian group that crossed vast distances of ocean to reach these remote islands, a new study finds.

Easter Island (also known as Rapa Nui) and Hawaii are part of Polynesia, a group of more than 1,000 islands spread over an area of the Pacific Ocean roughly equal to the areas of North and South America combined. Hawaii and Easter Island are the farthest of these isles from each other, at about 4,500 miles (7,200 kilometers) apart — around the distance from San Francisco to Lima, Peru.

The researchers discovered the connection by analyzing the genomes of 1,050 modern individuals across Polynesia, including 317 Native Hawaiians and 12 Easter Islanders. "Each person's genome contains genetic code from both parents, and from all four grandparents, and their parents, and so on," study co-author Alexander Ioannidis, a computational geneticist at Stanford University, told Live Science. "Each genome encodes an enormous number of ancestors. So with even a few individuals, we can get information about an enormous number of people from each island."

Specifically, the scientists compared the length of chromosomal segments shared among people from different islands. The longer these shared segments are between two people, the more recently they shared a common ancestor.

Even though Hawaii and Easter Island are far-flung, the researchers discovered that the Indigenous people of Hawaii and Rapa Nui are the most genetically related to one another. The team reported its findings Oct. 8 in the journal Science.

"This was really shocking at first — these islands are so distant from one another," Ioannidis said.

The scientists found that Hawaii and Easter Island were likely both settled by members of a single "ultravoyager" culture from the Mangareva islands, about 3,440 miles (5,530 km) southeast of Hawaii and 1,600 miles (2,600 km) west of Easter Island. (In 2020, the researchers found that members of this ultravoyaging group had mixed with Indigenous people in what is now Colombia, although it's unclear if this partnering occurred on an island or on the continent.)

"Once you know there was this extremely capable long-distance ultravoyaging culture capable of reaching one of these islands, having it reach the other makes more sense," Ioannidis said.

The area near Mangareva, including the Austral Islands, the Society Islands, the Marquesas Islands, and the Tuamotu Archipelago, "spans an area the size of Europe," Ioannidis said. "Sailing in-between these islands would have required skilled navigation. So it makes sense that developing such long-distance navigation skills would have ultimately helped people settle far-off Easter Island and Hawaii."

All in all, these genetic findings suggest the ancestors of Native Hawaiians and Easter Islanders shared some time together as a common group after splitting away from the population of ancient Mangareva. Some members of this group then went on to settle Hawaii, and others from this Mangareva group voyaged to Easter Island.

This new genetic data linking Hawaii, Easter Island and Mangareva "agrees very well with what we see archaeologically," Patrick Kirch, an archaeologist at the University of Hawai'i at Manoa who did not take part in this research, told Live Science. "It gives scientists a lot of confidence when independent lines of evidence from different disciplines give similar results."

Founder effect

The researchers also investigated the effects of genetic bottlenecks that resulted when these islands were settled by small numbers of people — phenomena known as "founder effects."

"If you have a rare genetic trait that happens to occur in this small number of individuals, if this small population grows rapidly, this trait can go on to show up in a high percentage of the resulting population," Ioannidis said. "So if a rare genetic variant once only affected a few people, it can start affecting a decent number of individuals."

The scientists found that Native Polynesian populations examined in the study often experienced a compounding set of founder effects over time. This is because islands settled by a few people then went on to send out small groups to settle other islands, and so on.

Previous research has looked at the founder effects in groups of European descent, such as the Amish, Finns and Ashkenazi Jews, resulting in standard screenings for certain genetic conditions in these groups.

The new study revealed that an even stronger founder effect has been overlooked among Native Hawaiians, with founder effects more than 10 times larger than in those European groups.

"The founder effect doesn't just reflect genetic diversity, but also cultural and linguistic diversity," Kirch said. "It probably helps explain why the cultures of eastern Polynesia all share a lot in common — they all trace to one central group."

These findings not only shed light on Polynesians' past, but also their current health. The researchers found that three genetic variants that are exceedingly rare among the global population — linked with dislocated lenses in the eyes, progressive vision loss, and kidney failure — are carried by 2 to 3% of the eastern Polynesians they studied.

"There should be a lot more resources going into learning more about gene variants of potential clinical significance among this population of Native Hawaiians, which is twice as large as the U.S. Amish population," Ioannidis said. "There are really opportunities for precision health here."

Astronomers using the James Webb Space Telescope (JWST) have discovered a galaxy with a glowing ring of newborn stars shining in the early universe. The galaxy, which the researchers observed as it appeared just 2.1 billion years after the Big Bang, is the most distant ring galaxy ever found.

The ring galaxy, known as GS18660, may be the result of a collision between two galaxies, the researchers reported in their study, published Sept. 8 in the journal Astronomy & Astrophysics.

It's rare to find the possible snapshot of a merger like this, given the timescales involved in these systems, Christopher Conselice, a professor of extragalactic astronomy at the University of Manchester in the U.K. who was not involved in the study, told Live Science. Although interactions between galaxies may have been common in the early universe, the creation of ringed systems like this is thought to be unusual.

"In this sense, the galaxy system is quite unique and may give us important information about early galaxy formation," Conselice said in an email.

A surprising discovery

Scientists selected GS18660 for observation because it looked stretched out in older Hubble Space Telescope images.

"We therefore did not target GS18660 specifically as a ring galaxy," Michele Perna, a postdoctoral researcher at the Spanish Astrobiology Center and the first author of the study, told Live Science in an email. "When we observed it with JWST [Near-Infrared Spectrograph instrument], the much more detailed data revealed the prominent ring structure and allowed us to investigate the galaxy in three dimensions."

Using JWST, the team looked at the galaxy's unique shape, tracked the motions of its hot gas, analyzed the gas's chemical properties, and studied the galaxy's star formation history.

Intruder-driven rings

When a small galaxy plunges through the center of a larger galaxy, the impact creates a wave of dense gas that ripples outward, similar to how water moves when a stone is dropped into a pond. As a result, a collisional galaxy is formed. Gas piles up along the wave and forms stars, producing a ring. These galaxies are rare in the local universe, and the few candidates found in the distant universe have been hard to confirm.

Several clues support the case for GS18660 as a collisional ring galaxy. For one, the researchers spotted a small companion galaxy, moving away from GS18660 at about 264 miles per second (425 kilometers per second). They also detected a bridge of gas linking the two, and the velocity along it changed, Perna noted. The change in velocity along this bridge-like structure indicates that the companion and GS18660 may be interacting.

Its position is also important, Perna added ‪—‬ the companion is located roughly along the main galaxy's minor axis, consistent with where an intruder would be expected to appear after a head-on plunge through the galaxy's disk.

Backed by stars

Using the companion's speed and distance, the team estimated a rough timeline for the impact. It revealed that the collision happened about 17 million to 42 million years earlier in the galaxy's history. This time scale seems reasonable, Conselice said.

He explained that it is difficult to determine the age of a past interaction directly, but that if one did occur, it must have happened around the time a rapid star-formation episode began and its age should be consistent with the average ages of the star clusters.

Looking at star formation rates with different instruments, the team estimates that 10% to 20% of the stellar mass in the ring formed in the past few tens of millions of years. This suggests that the collision and the ring's burst of new stars might have happened at the same time, so they were most likely caused by the same event, Perna explained.

"It is not, by itself, definitive proof of a collision, but together with the bridge and the ring morphology, it strengthens the case for a recent impact," Perna noted.

The discovery may also shed light on how common these kinds of collisions used to be. Whereas earlier estimates suggested that collisional rings in the early universe might be about as rare as they are today ‪—‬ around 1 in 10,000 galaxies ‪—‬ the new findings hint that head-on collisions that form ring galaxies may be more common in the early universe.

"If GS18660 is confirmed as a collisional ring, it would therefore suggest that we need to revisit our estimates of how frequently these systems occur in the distant universe," Perna said

Another explanation?

The team expressed caution about how much the data can prove. "It is really the combination of several pieces of evidence rather than one single observation," Perna said. "So we regard the collisional interpretation as our preferred scenario rather than a definitive conclusion."

Conselice thinks the evidence presented in the paper is consistent with a genuine collisional origin for the ring. "It looks to me like the merger hypothesis is more likely, given the nearby galaxy intruder and the stability of the intruder galaxy and the main galaxy itself," Conselice said. “Overall, it is convincing evidence that a past interaction and/or merger has occurred for this galaxy system based on the light distribution."

The other competing explanation involves a stellar bar. It proposes that the ring was not made by an intruder at all. GS18660 also shows a bar-like structure running north to south, and bars can funnel gas and stars into rings at specific distances from the center. Perna said the team cannot yet tell whether this is a true stellar bar or a result of the interaction.

A bar would be an exciting finding, too. JWST has already discovered barred galaxies in the early universe, including CEERS-2112. But researchers have not yet found a clear example of a bar-driven ring so early in the universe.

"Whether the ring was triggered by another galaxy or by the internal dynamics of GS18660," Perna said, "the result would tell us something important about how galaxies were already becoming structurally organised when the universe was only a few billion years old."

Editor's note: This article was updated on Oct. 29 to correct a typo. In the image caption, the lead researcher's surname was mistakenly written as "Pera," rather than "Perna." This has been corrected.

An experimental medical implant that removes excess sugar from the blood has shown promise in treating diabetes and obesity in tests with lab mice.

Coupled with a continuous glucose monitor, which tracks blood sugar levels in real time, the tiny device is designed to adjust blood sugar levels according to a patient's needs. It does so using a chemical reaction powered by electricity. In the mouse experiments, it prevented sudden insulin spikes and promoted fat loss.

The implant, described Oct. 22 in the journal Science, could offer a completely new way to treat diabetes and obesity, study co-author Martin Fussenegger, a professor of biotechnology and bioengineering at ETH Zurich, told Live Science in an email. His team is now working toward testing the device in additional lab animals, and eventually, humans.

About 790 million people have type 2 diabetes globally, and over 1 billion have obesity. People with obesity often have insulin resistance, in which cells don't respond to insulin well and can't take in the sugar they need from the blood. At first, the body makes more insulin to compensate, but eventually, it can't keep up; this sets the stage for prediabetes and type 2 diabetes. About 90% of people with type 2 diabetes also have obesity or are overweight.

At the same time, chemical reactions in the liver convert the extra glucose in the blood into fat stores, contributing to further weight gain.

Current treatments for these conditions focus on either lifestyle changes, such as diet and exercise, or long-term medications such as metformin, which lowers blood sugar, and GLP-1s, which reduce appetite to promote weight loss. But Fussenegger and colleagues wondered if they could target the glucose directly.

They designed an inch-long reactor that converts glucose into a harmless byproduct, called gluconate, through a controlled chemical reaction triggered by tiny amounts of electricity. This transformation takes place at an electrode coated with gold and platinum nanoparticles embedded within a graphite felt.

Crucially, the reaction occurs only when the device receives sufficient electricity, so the glucose removal can be switched on and off by controlling how much power is supplied to the implant.

The device is wireless and is both powered and controlled from an ordinary smartphone. The phone emits low-level radio frequency energy, which the implant's electronics then convert to a stable DC current to activate the reaction. Combined with a glucose monitor, the device detects high blood sugar and then sends feedback to the smartphone, which then adjusts the amount of power transferred to the implant.

"In principle, this enables the device to remove more glucose when [blood sugar] levels are elevated and reduce its activity when glucose returns towards the desired range," Fussenegger said. "The objective is to create an autonomous system that continuously adapts to the patient's metabolic needs."

The team tested this self-regulating medical device in mice with both diabetes and obesity. Over six weeks, the mice fitted with the implant had much more stable blood sugar levels than the untreated mice did. They also lost an average of 10% of their body weight.

Because the mice's glucose was consistently maintained within normal levels, the body's metabolic chemistry shifted toward fat burning, while the on-off regulation of the glucose-removal reaction prevented the mice's sugar levels from falling below safe limits.

It's an exciting proof of concept, Fussenegger thinks. However, "one important challenge is demonstrating that the device can convert sufficient quantities of glucose in a human while maintaining long-term safety and catalytic efficiency," he said. In other words, they still need to show that the chemical reaction works at the larger scale required to treat a human patient.

In a separate test, the team introduced the device to a large beaker filled with a sugary solution, to see if it could cope with larger volumes of glucose. The amount, about 1.3 gallons (5 liters), was similar to a person's total blood volume. The device still effectively controlled sugar levels in this larger system.

The test is not a substitute for research in larger animals and human patients, though, Fussenegger said. Those studies are the team's next priority.

Importantly, "our device is not intended to replace healthy nutrition, physical activity, or preventative medicine" for the treatment of diabetes and obesity, Fussenegger said.

"Obesity and type 2 diabetes are complex conditions involving much more than elevated glucose levels," he added. "We see it as a potentially powerful addition to the therapeutic toolbox, one that could eventually be combined with established treatments and lifestyle interventions."

This article is for informational purposes only and is not meant to offer medical advice.

This eye-catching satellite snap from a decade ago shows a pair of hurricanes barreling toward Hawaii. The clouds swirling around the twin cyclones make them look eerily like the eyes of a pale face smiling up at space. The sight appears even spookier when viewed on a weather map (see below).

The surprisingly symmetrical storms — Hurricane Madeline (left) and Hurricane Lester (right) — were the 14th and 13th named storms, respectively, during 2016's Pacific hurricane season, which is tied for the sixth-most-active year on record, with 22 total named storms.

Madeline peaked as a Category 4 storm on Aug. 30, reaching maximum wind speeds of around 130 mph (210 km/h). Lester also briefly became a Category 4 storm on Sept. 1, reaching a maximum speed just below Madeline's, but it quickly weakened to Category 3.

On Aug. 30, the day after the image was taken, Madeline was just under 400 miles (650 kilometers) from Hawaii's Big Island, while Lester was around 900 miles (1,450 km) behind on the same trajectory, according to NASA's Earth Observatory. At the time, meteorologists were uncertain whether the pair would hit the island.

The Central Pacific Hurricane Center later issued a hurricane warning for the state of Hawaii, saying that Madeline, in particular, would pass "dangerously close to the Big Island," according to the Earth Observatory. However, neither storm ended up making landfall. (In the photo, the Big Island is obscured by reflected sunlight, known as a sunglint, on the left side of the image.)

Madeline eventually passed south of Hawaii on Aug. 31. However, by then, it had been downgraded to Category 1. Lester passed north of the Big Island on Sept. 2 and came within around 130 miles (210 km) of Honolulu, before sharply turning northward, where it petered out.

Although neither hurricane made landfall — meaning the eye of the storm did not pass over a landmass — they still caused high winds, heavy rainfall and strong surf across the state.

Despite being in the middle of the corridor where most Pacific hurricanes form, Hawaii's islands have surprising good luck in avoiding the supercharged storms.

For example, in 2025, Hurricane Kiko was similarly spotted from space bearing down on the island state. But like Madeline and Lester, it suddenly changed course and weakened at the last minute.

Hawaii usually manages to dodge the worst effects of hurricanes for two reasons. First, the islands are surrounded by a near-constant area of high pressure on their eastern side, where most hurricanes come from. Second, strong winds often blow eastward across the islands, according to FOX Weather. These factors create a sort of invisible shield around the islands, causing storms to skirt around them.

However, given the recent rise in extreme weather events across the globe — caused by human-caused climate change — as well as changes to regional weather patterns, the islands may not stay so lucky forever.

For example, in August and September, two hurricanes — Lowell and Lala — skimmed unusually closely past the island of Kauai, causing a significant amount of damage to power lines, boats and other coastal infrastructure. Researchers think the ongoing "super" El Niño, which officially began in May and has already caused record-breaking sea surface temperatures in the Pacific Ocean, may be partially to blame for these storms, according to The Guardian.

See more Earth from space

Over the past six years, orcas have made headlines for a unique behavior: Some individuals have repeatedly damaged or destroyed rudders on boats. The behavior has prompted a wide range of explanations, including that it's playful, a form of revenge, a warning against getting too close to the pod, or even a type of cultural transmission, in which one orca observes another interacting with a boat and then imitates it.

But Christian Frings, a cognitive psychologist who studies how humans control their actions, thinks it could be deliberate.

While Frings, who is also chair of general psychology and methodology at Trier University in Germany, does not study orcas directly, he believes that theories developed to explain human behavior could provide insight into this orca behavior. Orcas (Orcinus orca), he said, may be a "test case" for whether a wide variety of species can anticipate how their actions will change the environment and then take those actions deliberately, with the goal of making those changes.

He published his theory as a commentary Sept. 8 in the journal Animal Cognition.

This doesn't necessarily mean orcas have wicked motives or are ramming boats with the goal of sinking them and scaring or harming people. It may be that orcas just like the sensation of smashing into a rudder or being in the water with a wonky, disabled boat. Once they learn this, they anticipate the effect — for example, how a boat moves or feels when the rudder is damaged — and then carry out the learned action sequence that creates that effect.

Frings' theory doesn't attempt to explain why orcas (also called killer whales) would seek to damage a boat or rudder. "Why they want this effect is a secondary question and while of course interesting it touches a quite different topic," Frings told Live Science via email.

Live Science spoke with Frings about his hypothesis and why theories that describe how humans execute a series of motor behaviors — called action control frameworks — might help us understand how other complex animals behave in the wild.

Kenna Hughes-Castleberry: Why is it important to study orca behavior, and what can studying orcas tell us about animal cognition?

Christian Frings: In truth, I'm the wrong person to get that question because I should mention right from the start that I'm a cognitive psychologist. So usually, I'm studying human behavior. So, it's not really that I'm interested in orcas, per se, more in the question of what is actually comparable between human action control, human cognition and animal cognition.

KHC: Can you explain the action-control framework for our readers?

CF: It's a group of theories. The most important point is that agents — humans and maybe orcas — control their actions by actually anticipating the behavioral and the sensory consequences of their actions.

So let's take the example of turning the light on. The action starts with anticipating how it will look when the light is turned on. It does not start with pressing the light switch. It starts with the visual effect you're going to produce. This visual effect then actually retrieves from memory a motor program, and this motor program actually produces the anticipated effect. So it's all about anticipating action effects.

In the human action-control literature, that is the most dominant view from different theories of how humans actually control their behavior: by anticipating the effects they're going to produce.

KHC: How does that apply to the orca behavior?

CF: The typical explanation for [the boat-attacking behavior] is more stimulus response or cultural transmission. Stimulus response would mean, in this case, the rudder elicits an approach or attack behavior. So any rudder should just elicit this behavior. [Editor's note: Stimulus-response theory is a psychological concept in which a stimulus triggers a particular response from an individual. Examples include a cat being sprayed with water when on the couch and jumping off the couch in response, or a dog salivating when it smells food.]

Cultural transmission would actually be observational learning. That means one orca sees how another orca is attacking a rudder and then just imitates the behavior.

I'm not saying that these explanations [stimulus response or cultural transmission] are wrong, by the way. I just want to add an additional layer of explanation.

I suggest that they actually anticipate the sensory consequences of their action. So maybe they anticipate how it would look and how it would feel if they destroy the rudder. I would not call it [their behavior] play, but maybe they're just testing or probing what kind of effect they're going to produce.

It's a little bit like human babies, when they start to move — or move their arms or move their legs — they're also typically trying to produce effects, right? It's also when they develop language, this kind of babbling, right? That is a kind of testing or probing action effects.

Maybe this is something the orcas also do. I don't know. But at least it's [another theory].

KHC: So would the orca be anticipating something like the boat becoming impossible to steer?

CF: Actually, no. Let's assume for a moment it [that a broken rudder is] what they want to produce — because they somehow anticipate how it would look and how it would feel if this yacht cannot be steered anymore.

If they can anticipate, then this anticipation of this effect will retrieve from their memory what they have to do to actually produce this effect. And it's not about [higher-order] thinking. That is a very important thing.

So we do not need human-like intentions to impose that on the orcas. I'm not saying that, because I really think it's, in a way, comparable with turning a light on. When you turn your light on, you also do not have big thoughts about that. You just want to turn your light on. So you want to produce an effect, and you do not think about all the different, quite complex muscle movements you have to do if you actually press the light switch.

I would say, again, it does not really need higher-order cognition or something like that. We do not have to impose motives or complex thoughts on the orcas for that.

KHC: What are the bigger implications if your theory is correct?

CF: My point is just to look at this behavior from this somewhat different angle, adding this layer about action effects. Because if you, for a moment, take my ideas for granted and say, "OK, maybe he has a point," then this opens up the possibility to manipulate the orca behavior.

Because if the orcas anticipate effects and this action effect produces a certain behavior, if you change the effect — let's say the rudder [material] or the shell of the boat so that the orca thinks he's producing a certain action effect — then he shows his behavior, but this behavior does not produce the action effect anymore. So the orca will probably change the behavior. It might be dangerous because it might elicit somewhat different — maybe even more dangerous — behavior of the orcas, but it might also stop it.

But it gives you a natural angle to manipulate the orca behavior. [Editor's note: In a follow-up email, Frings noted that this could involve testing a different version of the boat rudder. If the original rudder, when damaged, leaves the boat floating in a "helpless" way, a second one could be tested that allows the boat to be maneuverable even when attacked. If Frings' hypothesis is right, then by breaking the link between the orcas' planned actions (ramming the boat) and the outcome they want (helpless boat), you could change the orcas' behavior.]

But again, if you try to change it this way, it might be a little bit dangerous. So I would not suggest doing that with a boat with real people on it, because if you change the environmental consequences, they [the orcas] might actually go a little bit crazy. Maybe they might try to produce this effect with a different kind of behavior, and that could be even more aggressive. But I don't know. I can't predict that.

KHC: So the orcas are a case study to test this framework, right?

CF: Exactly. And for the general approach, it's important to try to find action frameworks that can travel across species that are not specific for one particular species. Because at the moment, we might have action-control models for humans or action-control models for the great apes.

But maybe we can just have a family of action-control frameworks, because maybe orcas and humans, and at least the great apes, control their behavior concerning action effects in quite the same way, to be honest.

Another important point here that makes it, for me personally, very interesting: This is behavior in the wild. So a lot of the research on action control is typically in the lab under very controlled conditions, so in a way, this is moving from humans to orcas but also from lab into wild behavior.

I think one misconception is actually that the models from the lab are not applicable to behavior in the wild. That's not only true for orcas; it's also true for humans. And I don't like that.

And again, this paper is a nice showcase that lab models can actually be used to explain behavior in the real world.

This interview has been condensed and edited lightly for clarity.

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A pioneering NASA space telescope is no more. In sad news for Swifties everywhere, the Neil Gehrels Swift Observatory has officially ended its mission after more than 20 years of tracking the most powerful explosions in the universe since the Big Bang.

According to a NASA announcement, the Swift team shut down the telescope's science operations Tuesday (Oct. 20) after the observatory fell too low in its orbit to continue taking reliable measurements of the cosmos. In the coming weeks, Swift will drop even further, eventually passing a point of no return and taking a fiery plunge through Earth's atmosphere.

The observatory is the latest victim of intense solar activity, which increases the drag on satellites in Earth orbit and makes it harder for spacecraft to stay aloft. Swift has been losing altitude for a while, but the final straw came in August, when a costly mission to boost Swift's orbit with a private spacecraft failed, ending with the would-be rescue craft burning up in the atmosphere after a series of hardware malfunctions.

Swift is now beyond saving and, orbiting at just 171 miles (275 kilometers) above Earth, can no longer take reliable observations of space. NASA expects the spacecraft to break up upon reentry "in the next few weeks."

NASA knew Swift was in trouble when it went in; soon, it'll be lying on the cold hard ground. However, the Swift mission surpassed its goals by decades. According to NASA, the satellite launched in November 2004 on a primary mission intended to last just two years. In the end, Swift survived for 22 years, surpassing its intended lifespan by more than 10 times.

In that time, Swift made thousands of observations of exploding supernovas, intense gamma-ray bursts, and black-hole-related episodes of stellar destruction, contributing data to about 7,000 scientific papers, according to NASA.

Designed as a multiwavelength observatory, Swift watched the sky in optical, ultraviolet and X-ray light that made it well suited to track the aftermath of powerful energy bursts. Its greatest asset, perhaps, was its rapid response time; if an explosion flashed somewhere in the sky, engineers could swivel Swift to study it within minutes, NASA said.

"Swift was designed as a satellite dedicated to studying gamma-ray bursts, outbursts that came and went so quickly that no one could target them with large telescopes to learn more," S. Bradley Cenko, the mission's principal investigator at NASA's Goddard Space Flight Center, said in the statement.

Swift's fast-acting observations "played a major role in advancing our understanding of the changing universe and was part of a revolution in astrophysics," added Shawn Domagal-Goldman, director of the Astrophysics Division at NASA headquarters.

A neglected "ghost particle" may have dominated the universe right after the Big Bang ‪—‬ changing how the cosmos expanded in its first moments and reshaping the conditions under which matter won out over antimatter, a new study suggests. In other words, it may explain why anything exists at all.

The particle, a hypothetical "right-handed" neutrino, briefly could have held more energy than everything else in the infant universe combined, which would have sped up cosmic expansion and delayed key particle interactions, the study proposes. The research was published Sept. 8 in the journal Physical Review Letters.

Neutrinos are ghostly particles that rarely interact with anything. A typical neutrino from the sun could pass through a slab of lead a light-year thick — about 5.9 trillion miles (9.5 trillion kilometers) — before striking a single atom. Neutrinos come in three types, or "flavors," and switch between them as they travel, making use of a subtle quantum effect that works only if they have mass. Yet the Standard Model of particle physics predicts they should be massless.

One popular fix involves "right-handed" neutrinos. Particles spin a bit like tiny tops, and physicists call them left- or right-handed depending on how they spin relative to their direction of travel. A right-handed particle rotates like an ordinary screw being driven in, turning clockwise as it moves away from you. Every neutrino detected so far is left-handed and turns counterclockwise as it flies away, like a screw with a reverse thread.

"Right-handed neutrinos are hypothetical particles that do not feel the weak nuclear force, "unlike their left-handed counterparts, which are part of the Standard Model," study co-author Rishav Roshan, a theoretical physicist at the University of Southampton in the U.K., told Live Science via email. "They are characterized by having no electric charge and being much heavier."

"Right-handed neutrinos may mix with left-handed neutrinos, helping to explain the mass of the latter" and why they switch flavors, Roshan said.

The cosmic seesaw

In quantum physics, particles that mix can exist as a blend of two identities at once. In a theoretical framework called the seesaw mechanism, each ordinary neutrino carries a faint trace of a heavy right-handed partner, and that trace gives it a tiny mass. The heavier the partner, the fainter the trace and the lighter the ordinary neutrino — hence the name, after the playground ride whose ends move in opposite directions.

The particles could solve other puzzles, too. They "aim to address several issues, including the origin of neutrino masses, the matter-antimatter asymmetry of the universe, and the nature of dark matter," Roshan said.

The Big Bang should have made equal amounts of matter and antimatter, which would have annihilated each other, forbidding the universe as we know it from ever taking shape. Right-handed neutrinos play a crucial role in models' proposals that the "observed matter-antimatter imbalance arose from processes involving these neutrinos in the early universe," Roshan said.

In this picture, decaying heavy neutrinos left behind a slight excess of leptons — the particle family that includes electrons — that later became today's surplus of matter, he explained.

The seesaw framework usually includes three right-handed neutrinos, but because two are enough to explain the data, physicists often ignore the third, assuming it is too heavy or interacts too feebly with matter.

How the heaviest neutrino took over

In the new study, Roshan and Sudipta Show, a physicist at the Indian Institute of Technology Kanpur, examined what this neglected particle — which, in the team's main example, was about 100 trillion times as heavy as a proton — would have done after the Big Bang.

At first, the particle would have zipped around at nearly light speed, so its energy would have faded like that of light, which would have both spread out and stretched to weaker wavelengths as space expanded. But as the cosmos cooled, the particle would have slowed down and most of its energy would have become locked in its mass, which would have been only spread out. Its share of the cosmic energy therefore would have grown until it dominated, and the long-lived particle would have stayed in charge until it decayed into other particles, according to the team's computations.

The study reveals that the neglected right-handed neutrino "significantly impacts the early universe's expansion dynamics, driving a period of early matter domination," Roshan said. This change "affects various Standard Model interactions"‬ that could help to explain the matter-antimatter asymmetry, Roshan added.

Each interaction would have switched on only once it outpaced the expansion of space. Because a universe dominated by the heavy neutrino would have expanded faster, the interactions would have had to wait until it cooled further.

These interactions would have let the early universe distinguish lepton flavors, which would have affected how the matter surplus formed. Thanks to the delay, the team found, a lighter right-handed neutrino about 100 billion times as heavy as a proton could have produced the observed amount of matter before the flavors could be told apart — even after the heavy neutrino's decay diluted part of it.

Hard to test, but not out of reach

The heavy neutrino is far too massive to create in any particle accelerator, so tests must be indirect.

Gravitational waves — ripples in space-time — offer one such route. An era dominated by the heavy neutrino would have left a telltale kink in the background of early-universe gravitational waves, such as those from "cosmic strings" ‪—‬ hypothetical thread-like defects in space. The results can be tested through forthcoming facilities such as the Laser Interferometer Space Antenna (LISA) and the Square Kilometer Array Observatory (SKAO), Roshan noted.

LISA, a space-based European Space Agency mission, is scheduled to launch around 2035, while SKAO, a giant radio telescope project being built in Australia and South Africa, could catch such waves by timing distant pulsars. Tests could come "as these facilities come online and begin data collection," Roshan said. A faint hum from the hot primordial plasma would carry the era's imprint too, but at frequencies beyond what existing detectors could pick up.

There's a new type of landslide affecting northern latitudes, and it could affect more areas as the planet continues to warm.

These landslides, called permafrost detachment slides, occur in areas with relatively thin permafrost and seem to be a long-term impact of wildfire in these environments, according to a paper published Sept. 23 in the journal Geophysical Research Letters. Such slides have not been observed in the region before and may be unprecedented over the past 10,000 years or more, said study leader Joseph Young, who completed the work as part of his doctoral degree at the University of Alberta.

"It has been stable, and then it just flipped a switch, essentially," Young told Live Science.

Young and his colleagues were doing field observations in Canada's Northwest Territories when they noticed large landslide scars in valleys that have long hosted stable permafrost, which is sediment that remains frozen year-round. They began using satellite imagery to map the changes and also conducted fieldwork, which revealed that the slides weren't standard melting permafrost.

"Typically with permafrost, everything just thaws and melts in a slurry and moves like a mud downslope," Young said. "But with these large landslides, we found blocks of frozen material in the debris."

Some of these blocks were 33 feet (10 meters) tall, the height of a two-story house. The researchers ran an electrical current through the ground to determine the depth of the permafrost on the slopes.

They focused on two slides. One, in the Johnson River Valley, took place in 2017 and moved more than 636 million cubic feet (18 million cubic meters) of soil and rock. The other, in the Redstone River Valley, moved almost 159 million cubic feet (4.5 million cubic meters) of debris in 2018. The smaller slide left a scar three-quarters of a mile (1.2 kilometers) long, while the larger one gouged nearly 2 miles (3.2 km) out of the hillside.

The researchers then used the data they'd collected to build a model of how these icy slides occurred. The permafrost in this area has been warming by about 0.54 degrees Fahrenheit (0.3 degrees Celsius) per decade since 1980, when monitoring began, and there were also severe wildfires nearby in 1995.

The researchers found that instead of a top-down melting process by which the permafrost thawed to a muddy slurry from above, the slides were instead caused by a combination of fire-related thaw and warming temperatures, leading to cracks near the top of the slopes. These cracks allowed the thaw to penetrate deeper, eventually melting the bottom of the permafrost layer. This propagation can take 20 years to penetrate 66 feet (20 m), which is exactly what happened in the Johnson River and Redstone River valleys.

"We had a fire in '95 and then 20 years later, we start to get a lot of these widespread disturbances," Young said.

The two large slides the researchers studied are among more than 150 in the area, Young said. The others are smaller, but they still typically move over 35 million cubic feet (1 million cubic meters) of land apiece. Canada's Northwest Territories are remote, so the permafrost detachment slides have yet to damage any infrastructure. But the two in the study did dam rivers, creating brand-new lakes and rapidly dumping sediment into the waterways downstream, Young said.

There are many other places in Canada and Alaska where the permafrost is 66 to 130 feet (20 to 40 m) deep and thus vulnerable to the same type of slide. This is especially true given the increasing intensity of wildfire at northern latitudes, Young said.

"This is almost a potential glimpse into the future of what we might be able to expect in these areas with changing forest fire dynamics," he said.

More children, teens and very young adults are being diagnosed with colorectal cancer in the United States, and new research suggests they often experience aggressive forms of the disease.

While diagnosis rates are rising, the disease is still rare among young people. Colorectal cancer, which affects the lower intestines and rectum, is largely a disease of age: 55% of all colorectal cancers are diagnosed in people over 65, and only 16% occur in people ages 49 or younger, according to a 2026 study published in the flagship journal of the American Cancer Society. Only a few hundred cases per year are diagnosed in people under age 21 in the U.S.

Nevertheless, the numbers of cases in the very young are rising, even as colorectal cancer rates decline or hold steady in older individuals. This increase coincides with an overall rise in colon and rectal cancer rates in people under 50.

The reasons for this schism aren't entirely understood. People over 50 receive routine colonoscopies in which precancerous polyps are removed, and that likely accounts for much of the decline in colorectal cancer diagnoses in older adults. But researchers suspect that environmental factors, such as ultraprocessed foods and sedentary lifestyles, might be behind the growing rates in young people.

"Most of the research has really focused on the gut microbiome," the community of bacteria and other microbes that live in the gut, said Dr. Christopher Lieu, a professor of medical oncology at the University of Colorado Anschutz and a medical adviser to the nonprofit Colorectal Cancer Alliance.

Microbiome disruptions may spur inflammation, which, in turn, may trigger DNA mutations that cause cancer. But these mechanisms are complicated, Lieu told Live Science, and there likely isn't one simple reason young people's microbiomes may be getting disturbed.

"It's going to be extraordinarily more complex than that," he said.

Aggressive disease in young people

What researchers are starting to learn is that colorectal cancer in people in their early 20s or younger tends to be a more aggressive disease than that often seen in older people.

"We do feel like it is a bit of a distinct disease than what we're seeing in older adults," said Dr. Erica Arnold, a pediatric surgery research fellow at Nationwide Children's Hospital in Columbus, Ohio. In October, Arnold presented new research on colorectal cancer in people ages 21 or younger at the annual meeting of the American Academy of Pediatrics.

Arnold and her colleagues analyzed the cases of 84 patients diagnosed between 2012 and 2023. They found that the median age of diagnosis was 16 years old and the median duration of symptoms before diagnosis was only 12 weeks long.

Only about 20% of the patients had a close relative with colorectal cancer, suggesting that for many of these young people, the disease did not necessarily emerge due to hereditary factors.

Eighty percent of the study participants were diagnosed with Stage III or Stage IV disease, meaning the cancer had already spread locally and to lymph nodes or to other, distant organs when the patients were diagnosed. For comparison, in colorectal cancer patients of all ages, 60% are diagnosed in Stage III or IV, according to the Centers for Disease Control and Prevention (CDC).

In addition, Arnold said, one-third of the patients in their study had cellular markers of particularly aggressive cancer.

"Some of that might be related to delays in diagnosis," Lieu said, "but if you want my honest opinion, it does suggest that these cancers are developing differently."

The study's data was not nationally representative, but a recent analysis of CDC data has also found that colorectal cancer rates in youth are on the rise. In 1999, the diagnosis rate in kids ages 10 to 14 was 1 in a million. By 2020, it had risen to 6 in a million. For teens between 15 and 19, the rate of diagnosis went from 3 in a million to 13 in a million in that same time frame.

Unclear causes

There is no definitive reason for this rise, Lieu said. Research on the microbiome has suggested that processed food, antibiotic exposure in childhood, stress, reduced exercise and other lifestyle factors may contribute to this increased risk of colorectal cancer.

Some microbes may play a particularly strong role, at least in some cases of colorectal cancer. For instance, a specific variant of the common gut bacterium Escherichia coli is strongly associated with colorectal cancer; the variant carries a genetic segment and produces compounds that are toxic to genes. But this variant alone cannot explain all colorectal cancer cases in young people. Nor is it clear why the gut microbiome might be undergoing a shift in the first place.

"It may be a combination of food, antibiotic use and environmental exposures," Lieu suggested.

Regardless of the exact causes behind the cases, Arnold's new research pointed to the symptoms that deserve closer scrutiny in young people. Among the 84 patients in the study, 75% reported experiencing back and abdominal pain before their diagnosis, 45% had changes in their bowel movements, 43% experienced unexplained weight loss and 38% had rectal bleeding.

These are classic colorectal cancer symptoms, Arnold said, but they might be overlooked in this young age group because these same symptoms can have more common causes.

Parents should know that in most cases, stomach pain and gastrointestinal disruptions in kids are not caused by colorectal cancer, Lieu said, calling the cancer an "extraordinarily rare event." Nevertheless, pain or gastrointestinal upset that doesn't ease or that worsens over time needs a checkup, and symptoms like weight loss and blood in the stool are very unusual in kids and deserve extra attention.

"It's just important to investigate it to make sure we're catching colorectal cancer earlier rather than later in these patients," Arnold said.

This article is for informational purposes only and is not meant to offer medical advice.

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Archaeologists in Peru have found an elaborate 1,500-year-old tomb that may hold the remains of a high-status toddler from a pre-Inca civilization.

The burial, which is from the Moche culture, also contained vessels depicting prisoners with rope around each of their necks and a sculpture of a human-bird deity.

Moche (also known as Mochica) culture developed along the northern coast of what is now Peru from the third to the ninth century. They created agricultural lands in the region's desert landscape, and their archaeological record includes monumental temples, water canals, pottery, metallurgy, textiles and a distinctive form of art. The Moche didn't have a written language, but they left behind thousands of realistic portrait vessels, which are somewhat similar to the prisoner sculptors found in the toddler's burial.

In the newfound tomb, the team unearthed a small skeleton, which is likely the remains of a toddler who was, at most, 2 years old, Carlos Rengifo-Chunga, director of the University of Trujillo's Huacas de Moche Archaeological Project, told Live Science. The child's sex is unknown.

Rengifo-Chunga and his colleagues also found two copper objects in the burial: a mask-like disk covering the child's face, and a half-moon object on their feet. In addition, the burial contained 32 ceramic objects associated with Moche culture, including those depicting the prisoners and the deity.

The tomb was large compared to the child's small size, and could have easily held an adult, Rengifo-Chunga said. It dates to the sixth or seventh century, he added.

The team unearthed the tomb inside the Uhle Platform at the Huacas de Moche archaeological site in northern Peru. The Uhle Platform is a mausoleum, attached to the Huaca de la Luna temple, with a patio archaeologists call the Patio of the Serpents. Of the more than 80 burials previously uncovered there, the tomb represents the only known child to receive this sort of lavish burial.

The elaborate funerary treatment, including the use of copper, and the location of the tomb all suggest that the child belonged to an elite class of Moche society, Rengifo-Chunga said.

The two prisoner sculptures are associated with the "ritual of combat," a common theme in Moche art. In this sort of imagery, two warriors fight each other, and the loser is stripped of his clothes and weapons, tied around the neck with a rope and offered as a human sacrifice, Rengifo-Chunga said. The prisoners depicted on these two vessels were the losing warriors, and their presence in the burial of a child is rare.

"One would normally presume that these kinds of vessels represent something related to the deceased's life," Rengifo-Chunga said. For example, a vessel like this might signify that the individual took part in combat.

But a toddler couldn't have taken part in such an activity. In general, archaeologists wouldn't expect to see elements of an adult ritual in the burial of a child. "This expands our knowledge on Moche funerary practices," he added.

The sculpture of the presumed deity depicts a human body with bird wings and a bird tail, although for some scholars it might be interpreted as a god in transformation, Rengifo-Chunga said. The deity holds a square shield in one hand and a goblet in the other, and is flanked by two bird "assistants" wearing ceremonial garments.

Researchers will have to investigate whether the deity is a known Moche god, or a newfound addition to the pantheon. Either way, the object joins a contentious debate over whether the Moche pantheon consists of many gods, or just a few that can transform into many different versions, Rengifo-Chunga said.

The artifacts are now in the laboratories of the Santiago Uceda Castillo Museum in Peru, where they will undergo conservation treatment.

How much do you know about the first people to reach the Americas? Find out with our First Americans quiz.

In 1833, stone quarry workers discovered an ancient burial mound at Goblins' Hill near the town of Mold in Wales. At the center was a stone-lined grave that contained a fragmented skeleton and a gold, cape-like accessory that had been crushed over time. The Mold gold cape has a unique shape and style, and it is one of the finest examples of prehistoric goldwork ever found, according to the British Museum, where the artifact is on display.

The cape dates to Britain's Early Bronze Age (2500 to 1200 B.C.), a time that saw a metalworking revolution as artisans shifted from crafting flint tools to making weapons and jewelry out of gold, copper and bronze.

When the cape was originally unearthed, experts assumed that it had belonged to an ancient warrior, chief or religious leader, due to the spectacular design of the object, Benjamin Roberts, then curator for the European Bronze Age collections at the British Museum, told the BBC in 2010. But after the broken pieces of the cape were put back together, the small size of the artifact suggested it may have been worn by a woman or a child.

The Mold gold cape measures roughly 9.3 inches (23.5 centimeters) tall and 18.3 inches (46.5 cm) wide. It weighs about 1.2 pounds (560 grams) and was probably crafted from a single lump of gold about the size of a ping-pong ball.

The gold ingot was beaten incredibly thin, fashioned into a cape, and then embellished with decorations that mimicked beads or necklaces, according to the British Museum. Additionally, several hundred amber beads were found on the cape in the grave, which likely added to the gilded appearance of the accessory. Perforations around the neck opening suggest the cape originally had a lining made of leather or another perishable material that did not survive.

Because the gold cape, when worn, would restrict a person's upper arm movements, it may have been a ceremonial accessory that conferred religious authority and was worn only on special occasions. But experts are still unsure why the cape was buried in a grave. Nor can they confirm whether the person it was interred with was male or female, as the skeleton was not recovered by the quarry workers in the 19th century.

"The cape is unique — there is really nothing to compare it to in the whole of Europe," Roberts told the BBC. "This makes it more difficult to understand why it was made and what significance it had."

For more stunning archaeological discoveries, check out our Astonishing Artifacts archives.

Can you put together last week's Astonishing Artifact?