Western states that were thought to be resistant to prolonged drought may be more vulnerable than scientists previously believed, a new analysis of groundwater reserves in the Colorado River Basin finds.

Researchers revealed the four states that together make up the Upper Basin — Colorado, New Mexico, Utah and Wyoming — lost almost twice as much groundwater as the Lower Basin did during an intense drought in the southwestern U.S. between 2020 and 2022. The finding was unexpected and might signal a turning point for the region, because the Upper Basin has long been seen as more resilient to dry spells than the Lower Basin, said Esther Oyedele, a doctoral student in geosciences at Virginia Tech and the study's first author.

"The Upper Colorado River Basin has historically been considered more resilient because it receives more precipitation, particularly snowfall in the Rocky Mountains," Oyedele told Live Science in an email. "I think the important takeaway is that we should not assume that the Upper Basin will remain relatively resilient simply because it has historically received more precipitation and snowmelt."

The Lower Basin comprises parts of Nevada, California and Arizona. Less rain and snowfall means the Lower Basin naturally has less groundwater recharge, or less replenishment from other water sources, than the Upper Basin. On top of that, the Lower Basin generally has higher evaporation rates and substantial water demands, given that roughly 30 million of the 40 million people that depend on the Colorado River for water live in the Lower Basin, Oyedele said.

In the new study, published Oct. 13 in the journal Water Resources Research, researchers used satellite and hydrological data to estimate groundwater depletion across the Colorado River Basin between 2004 and 2023. The data included measurements of surface water, soil moisture and snow-water storage, as well as observations from the Gravity Recovery and Climate Experiment mission and its successor, called the Follow-On.

The results showed that groundwater depletion has been a persistent problem in the Colorado River Basin over the past two decades, but losses accelerated in 2019. The three-year drought that began in 2020 is the principal cause of this, because it shrank the snowpack in the Rocky Mountains, increased evaporation and boosted water demand across the basin, Oyedele said.

During the drought between 2020 and 2022, the Upper Basin lost around 4.2 cubic miles (17.5 cubic kilometers) of groundwater, while the Lower Basin lost about 2.3 cubic miles (9.4 cubic km). In total, the Colorado River Basin lost 14 cubic miles (58.3 cubic km) of groundwater ‪—‬ equivalent to 25 million Olympic-size swimming pools' worth of water ‪—‬ during the study period, between 2004 and 2023.

It's unclear why the deficit is so much higher in the Upper Basin than in the Lower Basin, but the Upper Basin's proximity to and dependence on the mountains for aquifer recharge probably didn't help, Oyedele said. As snow melts, some of it replenishes groundwater, so a reduction in snowfall between 2020 and 2022 would have affected the Upper Basin particularly badly, she noted.

The Upper Basin also recorded more aquifer recharge during wet periods before the drought than the Lower Basin did, so it's possible that the pronounced decline during the drought was linked to a higher initial amount of groundwater in the Upper Basin, Oyedele said.

Next, the researchers used advanced statistical methods to explore the relationship between groundwater and surface water in the Colorado River Basin. Due to global warming and the overallocation of the Colorado River's water in a 1922 document, the river's flow is now 35% less than it was on average in the 20th century. Water scarcity in the basin has reached alarming levels, according to the study, and Lake Mead and Lake Powell, the two largest reservoirs in the U.S., dropped to record lows in August.

The team found that in the Upper Basin, groundwater levels evolve in the same direction as surface water, but with a slight delay. This suggests groundwater losses occur due to a lack of recharge and more aquifer pumping during periods of drought, when surface water levels drop. In the Lower Basin, however, this link is weaker and more complex. The results showed that groundwater losses sometimes preceded surface water declines during the study period, suggesting that groundwater depletion is not simply tied to less surface water trickling into the ground or to humans extracting groundwater when there's less surface water available. Instead, groundwater is consistently being overused, Oyedele said.

"This distinction is important because it suggests that groundwater depletion is not simply a direct response to surface-water shortages," she said. "Human water use, particularly sustained groundwater extraction, may also play a significant role."

Looking ahead, it's hard to tell if the Upper Basin will continue to lose more groundwater than the Lower Basin and what that would mean for the region, Oyedele said. What seems clear, however, is that the Upper Basin is more vulnerable to drought than experts had thought.

"Continued warming, changes in snowpack, prolonged drought, and increasing water demand could place additional pressure on groundwater resources across both basins," Oyedele said. However, future groundwater responses will depend on several factors, including precipitation, snowmelt, water use and management decisions, she added.

On the management side, Oyedele suggested tackling groundwater and surface water together rather than as two separate resources. Groundwater helps to sustain river flows, and rivers can recharge aquifers ‪—‬ so the two are interconnected. Groundwater often serves as a backup during drought, but it shouldn't be treated as an unlimited reserve, she said.

The Milky Way's supermassive black hole is surrounded by a surprising trove of heavy metals, according to new observations by the James Webb Space Telescope (JWST). The metals may offer new clues about how Earth got its share of heavy elements — but it could also make one of the greatest mysteries about our local black hole even harder to solve.

In astronomy, metals refer to any element heavier than hydrogen or helium, with common examples including oxygen, carbon, iron or gold. These elements are forged through nuclear fusion in the hearts of stars that are reaching the ends of their lives, before being sprayed into space and incorporated into new generations of stars.

Scientists say the material spotted by JWST likely came from supernovas ‪—‬ stellar explosions that blasted the metal into the region around Sagittarius A (Sgr A*), the monster black hole in the middle of our galaxy.

The metals, detected as gas, appear to have the same composition as several nearby stars, which suggests both the stars and the gas originated at the same time. Researchers shared the observations in a paper published Oct. 19 in The Astronomical Journal, following up on work published in The Astrophysical Journal in May.

"We know there's a black hole at the centre of our galaxy pulling material into itself, but we see that it's eating a lot less material than other supermassive black holes, and more slowly," Nicole Ford, first author of the new paper and a doctoral student in astrophysics at McGill University in Montreal, said in a statement. "Part of understanding why this is happening means looking at the properties of the materials available for it to consume, including gas, dust and the stars orbiting around it."

JWST orbits at Lagrange point 2, which is about 1 million miles (1.5 million kilometers) from Earth in the opposite direction of the sun. The telescope identified the heat signatures of specific gas clouds billowing near the black hole, as well as the metal content within those clouds.

"These findings could advance understanding of how metals are distributed around supermassive black holes in more distant galaxies, as well as the processes that supplied Earth with many of these elements," McGill researchers said in the statement. The metals' presence "influences how quickly gases cool, which in turn influences how readily the gas can be drawn into a black hole," they added.

The previous study in The Astrophysical Journal showed that gas emissions near the black hole have been influenced by conditions in the local clouds. Unfortunately, this means the gas alone cannot serve as a proxy for how often the black hole has been active, the researchers said.

See how much you know about black holes with our black hole quiz!

A rare silver coin minted during the reign of a famous Viking king has been discovered in a massive hoard in Norway that now comprises 5,500 coins and counting.

The coin is inscribed with the name of the Norwegian king Olaf Haraldsson, who ruled from 1015 to 1028 and, as St. Olaf or "Olaf the Holy," is considered the national saint of Norway.

Fewer than 20 coins minted during Olaf's reign have ever been discovered, and the newfound coin is a "national treasure," according to a statement from the University of Oslo's Museum of Cultural History.

"Here we have a coin bearing the king's portrait and a cross, with another cross on the reverse," University of Oslo coin expert Svein Gullbekk said in the statement. "It is a Christianisation coin on a grand scale."

Olaf is credited with establishing Christianity in Norway — an early step toward its full conversion about a generation later.

"We can see how King Olaf used coinage to legitimise the new faith and to establish himself as a Christian king of European standing," Gullbekk said. "This is branding."

Viking king

Haraldsson learned about Christianity when he joined Viking raids against England and France as a young man, and he was baptized in the French city of Rouen in about 1013, according to the statement.

He became Norway's king in 1015, and in about 1024 proclaimed that only Christianity would be legal, according to the University of Bergen. Much of Norway, however, remained faithful to the Norse gods during his rule, especially around the central Trøndelag region and in the eastern parts of the country.

But Olaf was made a Christian saint shortly after his death in 1030. He is now recognized as one of the first Christian kings of Norway and the first Norwegian king to issue coins in his own name.

The newfound coin is part of the Mørstad Hoard, which was discovered near the village of Rena in April. At that time, the buried hoard was described as the largest ever found in Norway and was estimated to contain almost 3,000 silver coins. However, subsequent research has determined that it includes anywhere from 5,500 to more than 6,000 coins, the statement said.

Mistaken identity

Anne Skogsfjord, a museum researcher charged with cataloging the coins, thought the Olaf coin was an Anglo-Saxon penny at first. But then she read the inscription and realized it was minted in Norway under Olaf.

"I could see that it read ONLAF R+ NORMANORV. … Could this really be a coin of Olaf Haraldsson that I was holding?" Skogsfjord said in the statement. "And it was! It was a very special moment."

The coin was struck between about 1024 and 1028, near the end of the Viking Age, and circulated for 20 to 25 years before someone deposited it in the hoard, the statement said.

Although the minting of the coin was a political and religious act, the coin also seems to have been used as currency; both sides bear numerous small cut marks, which was a common way of determining whether a coin was made completely of silver.

Gullbekk said Haraldsson himself had decided what the coins would look like and may have been present when they were minted.

"It is entirely possible that this very coin from Mørstad was once held in the king's own hand," he said in the statement.

See how much you know about ancient norsemen with our Viking quiz!

The Nazis were far from completing a working reactor for their atomic bomb program, despite claims by the project's leader that it was almost ready, a new study finds.

The German physicist Werner Heisenberg wrote in 1947 that the reactor for the "Nazi bomb" project ‪— which culminated in Germany's B8 nuclear reactor ‪— was almost finished at the end of World War II.

Heisenberg, who led the reactor's development, claimed the reactor was "just insufficient" to create a self-sustaining fission reaction and that it lacked only a "relatively small amount of uranium" to work.

If it had worked, the B8 reactor would have confirmed that a fission chain reaction was possible, marking a key step toward the German development of an atomic bomb. It could have also spurred the development of specialized fission reactors used to create weapons-grade plutonium from uranium. Instead, the atomic bomb was developed first by the United States and was used to force the surrender of Japan in August 1945. (Germany had already surrendered in May 1945.)

The new study, published Sept. 29 in the journal PNAS Nexus, used historical documents and forensic investigations of two of the project's surviving uranium cubes to refute Heisenberg's claim. The new research indicates that the German B8 reactor had less than half the amount of "heavy water" and about half the amount of uranium it would have needed for a continuous chain reaction.

"My results argue that Heisenberg was off by roughly a factor of two," said first author Patrick Park, a doctoral student at Princeton University who co-wrote the study while at Columbia University.

Park said Heisenberg's mistake was understandable: His calculations were only approximate, and the project was relocated to a rock cellar in the town of Haigerloch, Germany, after Berlin was bombed.

"People were dying or starving and so these reactor calculations were not his first priority," while many details of neutron physics were unknown at that time, Park told Live Science in an email. "Given these circumstances, I think he did the best he could."

Heavy water

To answer the question of how far the reactor for the Nazi bomb project got, the scientists began by tracing archival records of hundreds of uranium cubes that had been used by German scientists. The B8 reactor consisted of five concentric circles of uranium cubes suspended on chains within the heavy water tank. The German scientists planned to place a radium-beryllium neutron source into the reactor's core to kick-start the chain reaction with a flood of neutrons that would split the uranium nuclei and release more neutrons, furthering the chain reaction.

Heavy water is a form of water that contains the neutron-heavy hydrogen isotope deuterium. Like the mainly-graphite blocks and rods used in many reactors, it can be used to "moderate" or slow down fast neutrons created in a fission reaction so they trigger fission — and more neutrons — in nearby uranium atoms. The Germans also used small amounts of graphite in their reactor, but as a coating to reflect neutrons back into the chamber.

By combining the records of the cubes, heavy water and graphite used by the German scientists with measurements of the two surviving cubes, the study authors created a mathematical model of the reactor that agreed closely with historical measurements. This enabled them to establish that the heavy water reactor was far from achieving a stable reaction. The findings also helped them examine the suggestion that the Germans should have instead built a graphite-based reactor like the nuclear pile developed at the University of Chicago to build the American bomb.

But the study authors determined that a graphite-moderated reactor was unfeasible in wartime Germany because the local supply of coal available to create graphite contained high levels of neutron-absorbing boron, making it useless.

Instead, the heavy water used in the B8 reactor was produced at a single factory in Norway, which was occupied by Germany from April 1940 until May 1945. However, the reactor contained only about 370 gallons (1,400 liters) of heavy water, instead of the more than 780 gallons (roughly 3,000 liters) it would have needed, the researchers determined.

Heavy water makes up a tiny fraction of a percent of ordinary water, and extracting it by electrolysis in the Norwegian factory took extraordinary effort. The factory was producing as much heavy water as it could, but the B8 reactor would have needed more than twice the amount it produced during the entire war, the researchers wrote.

Another finding is that the B8 reactor had about half the amount of uranium it would have needed to sustain a fission chain reaction. The reactor contained a total of 664 cubes, each weighing about 5.11 pounds (2.32 kilograms), for a total of 3,390 pounds (1,540 kilograms) of uranium. Similar cubes were distributed among other experimental groups, giving a total inventory in wartime Germany of about 1,100 cubes of uranium.

But the researchers determined that the B8 reactor would have needed at least 1,200 cubes to work. Germany, therefore, was not about to develop a reactor for an atomic bomb in 1945. Contrary to Heisenberg's claims, the heavy-water reactor was not nearly ready, and a working graphite reactor was impossible.

"We conclude Germany could not have built heavy water nor graphite reactors during World War II," the researchers wrote.

Mark Walker, a historian at Union College in Schenectady, New York, who wasn't involved in the study, said the findings explain Germany's decision to develop a heavy-water reactor, since a graphite reactor was not feasible and they didn't know at the time how much heavy water would be needed.

Walker is the author of "Hitler's Atomic Bomb: History, Legend, and the Twin Legacies of Auschwitz and Hiroshima" (Cambridge University Press, 2024) and a noted expert on Germany's wartime nuclear efforts. He agreed that Germany could not have made a graphite reactor during World War II.

"This paper argues that if the Germans had done something they did not do, then this would have failed," he told Live Science in an email. "While this is counterfactual history, it is an interesting engineering analysis."

Sailor Matt Rutherford has dreamed for several years of becoming the first person to circumnavigate the Arctic Ocean solo, nonstop and unassisted. He finally set out from western Greenland on June 25 to achieve this goal, but threatening encounters with Russia's security agency less than two months later forced him to reverse course.

Rutherford is the founder and executive director of the nonprofit environmental organization Ocean Research Project, which gathers and analyzes marine data from a sailboat. His route took him around the southern tip of Greenland, through the Denmark Strait and into the Greenland Sea. From there, he sailed through the Norwegian and Barents seas, and reached Russia's Novaya Zemlya archipelago in mid-August.

He was planning to continue to Canada and end his journey where it started, but Russian officials halted him in his tracks and ordered him to turn around.

On his way home, Rutherford told Live Science about his adventures and why he wants to complete this loop. In an interview on Sept. 23, he also revealed what he'll do differently on his next attempt to avoid another Russian interception.

Sascha Pare: Where are you currently, and what are the conditions like?

Matt Rutherford: I'm about halfway between Greenland and Newfoundland in the Labrador Sea. The conditions aren't too bad; I mean, it's close to a gale, but it's not quite a gale. [Editor's note: A gale is defined as an area of sustained surface winds of 34 to 47 knots (39 to 54 miles per hour).] It's just a little hard to do anything. I've got dishes in the sink that are all wedged in there that I really need to deal with ‪—‬ but I don't feel like it, because you're just getting tossed around. Waves are crashing on the cockpit. Normally, I do video calls under a dodger [a canvas screen on a boat or ship that provides protection from spray], and you can see the ocean in the background… But I'm going to get hit by a wave if I do that.

SP: You're sailing home to Maryland after a rather perilous expedition. How long have you been at sea for?

MR: I left in mid-May, and I've been basically underway for the most part since then. At this time, currently, I've only been at sea for a few days, because I left Greenland a few days ago. The longest stretch I was continuously at sea this year is 59 days, although I was planning on doing longer than that, so that sucked. Essentially, I was attempting to do a nonstop, single-handed circumnavigation of the Arctic. That's where this all sort of came out of. I tried in 2018, but you couldn't get the Russian permits. And the Russians were the problem in the end [this year]. I got defeated by Russian bureaucracy, essentially. And there was some weird stuff going on with the ice up there this year. [Editor's note: Sections of the High Arctic were impassable due to a relatively cold summer and solid ice fields.]

SP: What happened with the Russians that forced you to turn back?

MR: The FSB got me. [Editor's note: The Federal Security Service (FSB) is Russia's main security agency and a successor to the Soviet Union's KGB.] They boarded me twice, actually. I've never been boarded in the ocean in my life, and I've been sailing 20 years, all over the place. I got about 1,000 miles [1,600 kilometers] into Russia, roughly. I got into the Northern Sea Route. If you just draw a line due north, I was due north of West China — it was way over there, about halfway around the world in the Arctic. I made it about halfway, because I started in Aasiaat, Greenland.

They boarded me once, and then they turned me around and boarded me again. It's a bit of a strange situation, I guess. Two days after I turned around, the ice that I was waiting to open opened, and I sent them an email — the NSRA, the Northern Sea Route Association in Moscow — and said, "Hey, it's open. Can I pretty please go?" And they just got mad at me, like, "You'll be in violation of your permit; you have to turn around."

SP: You're planning to try the circumnavigation again next year. Will you do anything differently to make sure you complete it?

MR: The boat's pretty good to go ‪—‬ which is great, because that's a huge time sink. Ideally, hopefully, if I can get north of [the Norwegian archipelago] Svalbard again like I did this year, then I'm going to stay north of [the Russian archipelago] Franz Josef Land, and I'm going to basically ride the polar ice cap all the way from Svalbard to the Northwest Passage — all the way to Alaska and beyond, essentially.

Because I've learned how the FSB operate, and I know where they're keeping their ships now. Even though I was north of Novaya Zemlya, they still were able to get me. But if I'm over there, north of Frank Josef, they don't go that far, so they won't be able to get me up there. I've figured out a couple of other things that I'm not even going to say, honestly ‪—‬ there are workarounds to get them to [leave me alone]. I'm going to go a little bit quiet.

The NSRA gives you the permit to do this, but the FSB are the people who patrol it. And the FSB don't like the NSRA. I learned that when they boarded me, because they think that they're the ones who should control the Northern Sea Route, not the NSRA. So there's [a] beef between them; they don't talk. There's a lack of communication, which benefits me. I can lean heavy onto the NSRA side, because they don't have boats; they're not going to board you. And they're the ones you have to check in with every 24 hours in Moscow; you've got to send them an email every 24 hours. So I'll do all of that stuff with those guys, but I think there's some ways I can avoid the FSB even knowing where I am, essentially, while still complying with my permit in the NSRA.

Basically, I've got to do the Northern Sea Route without getting within 12 miles [19 km] of any Russian land, period ‪—‬ even a little island, even a rock that sticks out that's 10 feet by 10 feet [3 by 3 m]. That's going to be real tricky, because there are a lot of little islands down there. But the FSB is mostly on the European side; they have almost no boats over on the east side or the middle. So if you can get past the European side by hugging the coast way the hell north, hopefully I can get past where they patrol, and then I can just shoot on through.

Nobody else in the world does this ‪—‬ nobody else in the Arctic, nobody else anywhere. There's literally no other body of water on Earth where you've got to get permits, and then you've got to get boarded like this. It's only Russia, and only north of Russia. And that's because there's a huge amount of natural gas, they think, buried above Russia. So Russia's trying to claim everything to the North Pole.

Technically, it's international waters, so the U.N. is like, "No, this is not right." And Russia's like, "Whatcha gonna do about it?" It's kind of hard to argue with that ‪—‬ and it's north of Russia, so nobody else is there. They've got free rein, and they've got all the icebreakers and whatever else.

Everything else is about the same. I need to secure my hot sauce better, because every time I open my cabinet, they fall out all over the place. There's little things like that ‪—‬ quality-of-life things. I'll probably bring some more heated socks — electric socks and electric gloves. I'll try to make better videos — but I'm not a content creator, and I don't want to be an influencer.

SP: Can you tell me a bit about your background and what led you to this point?

MR: I did this whole circumnavigation of the Americas — nonstop, single-handed — back in 2011 where I spent 309 days alone at sea on this little 27-foot (8 meters) boat. When I got back from that big, crazy trip — which I made a documentary about ["Red Dot on the Ocean: The Matt Rutherford Story"] — I created a nonprofit called Ocean Research Project, where, basically, we use sailboats to do research. We focused mostly in 2013 and 2014 on garbage-patch-related microplastics. In 2013, we mapped out the eastern side of the Atlantic garbage patch, because nobody had got to the eastern side of it. I think it was 160,000 pieces per square kilometer, or something like that. And then, we did some stuff in 2014 in the Pacific garbage patch with the University of Tokyo; we did a joint paper with them.

But mostly what we focus on is Arctic research. Since 2015, we've been heading up to Greenland — sometimes the Northwest Passage also, but primarily Greenland — doing research related to glaciers, for the most part. An ocean-terminating glacier sort of has a river of melted water underneath it, and it creates upwelling, and the upwelling has nutrients. So it mixes nutrients with the ocean and creates this perfect recipe for growth for phytoplankton and zooplankton. And then, we look at the different stages of decay between an ocean-terminating glacier, a land-retreated glacier or a deglaciated fjord. In the middle phase, when a glacier starts retreating back on land, it just creates a river of muddy water, essentially; it turns the fjord into a mud puddle. You can't have photosynthesis if you're in a mud puddle.

SP: Have you been collecting samples or data on this expedition?

MR: Well, it's a little tricky on a boat under these circumstances. I took 50 samples, which were just water samples, and those were from Newfoundland to Aasiaat, Greenland. Nicole [Nicole Trenholm, Ocean Research Project's science director] has a NASA internship out at JPL [Jet Propulsion Laboratory]. She was publishing a paper looking at their model that they have [ECCO-Darwin], and I've kind of forced my way into the paper — well, the organization did, with Nicole's help — by adding these samples. Now we have in situ data, physical data, that we can compare to the model data. That was the only thing we did this year. It's a couple-thousand-mile stretch with 50 water samples in it, so it's a pretty straightforward sort of thing.

Nicole is trying to publish multiple peer-reviewed scientific papers from our previous data. She's got a traffic jam of data, so she needed some time to finish publishing papers from stuff we've collected over the last few years. There is no money anyways. I could still grab some samples on the way up there [Greenland]. And it's trying to promote the nonprofit through it, because people will pay a lot more attention to this stuff than they pay to traditional research expeditions.

SP: What are your hopes for the Ocean Research Project once you tick off this goal?

MR: Basically, we're trying to expand the organization over the next couple of years. I'd like to bring in another one or two more scientists, because we're up there for three months in Greenland, and sometimes we go to the Northwest Passage — and it's a lot for one scientist.

The big problem we're having is that when Elon Musk was part of DOGE [U.S. Department of Government Efficiency], they cut a massive amount of polar funding — something like 88% of it — because apparently climate change is a hoax and they hate it and you're not allowed to research it either, right?

Basically, nobody's got money. We don't typically get NSF [National Science Foundation] funding; we get more foundation funding, because it's hard to get NSF funding, even before all this stuff. Now that the funding has been cut on the governmental level, a lot more scientists are going after the foundation grants that we used to have a lot less competition for. That makes it a little tricky, too, because now they're getting a flood of requests that they didn't usually get in the past.

This interview has been condensed and edited lightly for clarity.

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Astronomers have discovered the lightest known pair of neutron stars — two ultradense stellar remnants that circle each other every 2 hours, 22 minutes, veering toward an inevitable collision about 82 million years from now. By timing radio pulses from one of the stars, the researchers detected three subtle effects predicted by Albert Einstein's general theory of relativity and found that the theory describes the pair's motion to within about 1% — proving the visionary physicist right yet again.

The researchers published their findings Sept. 15 in the journal Physical Review Letters.

Neutron stars are the collapsed cores of massive stars that exploded as supernovas. Each packs more mass than the sun into a ball roughly 12 miles (20 kilometers) in diameter. Some, called pulsars, spin rapidly and sweep beams of radio waves across the sky like cosmic lighthouses. Their rotation is so steady that their pulses work as extraordinarily precise clocks.

Very few pulsars orbit another neutron star. "There are only 30 such double neutron star systems, and the relativistic effects are very strong if they are in compact orbits," study co-author JinLin Han, an astronomer at the National Astronomical Observatories of the Chinese Academy of Sciences, told Live Science via email.

The first such pair, discovered in 1974 and known as the Hulse-Taylor binary, provided the first evidence for gravitational waves — ripples in space-time predicted by Einstein. Such waves carry energy away from an orbiting pair, so its orbit should gradually shrink, and the Hulse-Taylor orbit shrank at just the rate Einstein's theory predicted.

Later, the "double pulsar," which completes an orbit every 2.45 hours, matched the predicted rate to within about 0.01%. Eventually, this shrinking forces such pairs to merge, unleashing gravitational waves like those the Laser Interferometer Gravitational-Wave Observatory and Virgo interferometer picked up in 2017.

A newly discovered pair

The new system, designated PSR J1856-0039, lies roughly 4,200 to 6,500 light-years from Earth. In 2020, it turned up in a survey of the Milky Way's disk by China's Five-hundred-meter Aperture Spherical Radio Telescope (FAST), the world's largest single-dish radio telescope.

"We have discovered about 900 pulsars," Han said of his team's work. "After a few follow-up observations, this one is very extraordinary."

The pulsar spins about 43 times per second, and the two stars are separated by roughly twice the distance between Earth and the moon. But the "most attractive feature" is the short orbital period of about 2.36 hours, Han said. "This is the second-shortest one, and it must show stronger relativistic effects than the famous double pulsar and the Hulse-Taylor system."

The team observed the pair with FAST 17 times between 2020 and 2025, sometimes long enough to cover a whole orbit. The researchers measured the arrival times of the system's pulses and then fit that data to orbital models that accounted for relativistic effects, like subtle changes to the pulse arrival times at different parts of the stars' orbits.

"With so many measurements by FAST, which would be hard to match in accuracy with other telescopes, we got not only the basic parameters of the pulsar and its orbit but also three relativistic effects," Han said.

First, the orbit is shrinking as the stars radiate gravitational waves, drawing them about 9 feet (2.7 meters) closer each year. Second, the oval orbit turns slowly, by 17.6 degrees per year — some 150,000 times faster than the relativistic drift of Mercury's orbit. Third, because both gravity and speed slow time, the pulsar's clock runs at a varying pace along the oval orbit, shifting its pulses by up to about half a millisecond.

"From these measurements, we determined the pulsar mass and the companion mass," Han explained. "The total mass is the lowest among all known double neutron star systems." The pulsar weighs about 1.3 times as much as the sun, and its companion is just 1.19 solar masses — one of the lowest-mass neutron stars known. Simulations suggest that supernovas can't forge neutron stars much lighter than that.

The stars will merge in about 82 million years. That merger will probably leave behind a heavier neutron star of about 2.26 solar masses, though the remnant could instead collapse into a black hole, the researchers estimate.

Another win for Einstein

Any two of the three effects are enough to calculate both stars' masses. The third then serves as an independent check, because if general relativity is correct, all three must point to the same masses — and they do.

"We found that general relativity is needed to explain the data, and the consistency is about 1%," Han said. The double pulsar test is more precise, but it drew on 16 years of data, compared with about five for the new pair. "Unfortunately, we could not beat this description of gravity," Han added, referring to physicists' hope of finding cracks in Einstein's theory that might reveal new physics.

Next, the team hopes to detect "frame dragging," an effect in which a spinning mass twists space-time around it, making nearby orbits wobble. "In the future, we will monitor this pulsar, probably over decades, to detect the frame dragging induced by the neutron star's spin," Han said.

Measuring the effect would reveal the pulsar's moment of inertia, which depends on how its mass is spread out inside. That would provide "a novel constraint" on how matter behaves at the crushing densities in neutron star cores, Han said — one of the biggest open questions in physics.

See how much you know about black holes with our black hole quiz!

The patient: A 29-year-old man in India

The symptoms: The man, a fighter pilot in the Indian Air Force, went to a civilian neurologist after having persistent headaches for 18 months. The headaches would occur approximately two to three times per month, starting in the late afternoon and lasting up to three days. Sleep did not improve his symptoms.

The pain was typically greater on the right side of his head, but he would often feel pain on the left side as well. The pilot also reported that just before a headache, he would experience a "sense of lousiness," his doctors wrote in a report of the case.

Sometimes, the pain was so intense that the man was unable to take part in scheduled flights. If he flew anyway during an episode, his headache would be even worse the next day.

What happened next: According to the man, his finances and personal relationships were not a source of stress. (Stress, in general, is a very common headache trigger.)

When asked about his medical history, the pilot recalled no recent ailments or conditions that could cause recurring headaches, such as inflammation and congestion of the sinuses (sinusitis). He had no family history of chronic headaches or migraine, a neurological disease that frequently causes moderate to severe headache, among other symptoms. Nor did he experience nausea, vomiting or visual anomalies called "auras," which often accompany or precede migraines.

Nevertheless, the civilian doctor determined that migraines were the culprit. He prescribed divalproex ‪—‬ an oral medication used for migraine prevention — and told the patient that he would likely need this medication for years. Concerned about taking the drug over a long period, the pilot decided to consult an authorized specialist at a military medical facility for further evaluation.

The diagnosis: The military doctors reviewed the pilot's case and examined him. All of his test results were in the normal range, and a CT scan showed no brain abnormalities. They ordered a nasal endoscopy — an exam that uses a camera to examine the nasal cavity and sinuses — and found that the patient had a deviated septum. However, the deviation was so minor that they ruled it out as a possible cause of his pain.

Finally, the doctors agreed with the initial diagnosis: The pilot was experiencing migraines. The causes of migraine are not fully understood, although genetics and environmental factors may contribute to both the duration and intensity of migraine pain in a given individual.

The treatment: The pilot was given the migraine medicine sumatriptan, to be taken at the first sign of pain, and aspirin, to be taken during headaches. He was allowed to continue flying under restricted conditions, and he had to report to a military neurologist for monthly reviews over the next three months.

Four months later, he was headache-free and had stopped taking medication, according to the report. However, his superior officers needed a detailed medical review before they could restore his unrestricted flight status, as severe migraines can disqualify pilots from flying.

Over three days, doctors conducted in-depth interviews with the pilot, focusing on the first appearance of his symptoms and the circumstances leading up to his headaches. They were puzzled by certain details: His lack of nausea, vomiting and auras, and the fact that he got no relief through sleep. These facts raised questions about the migraine diagnosis.

During the interviews, the pilot recalled that his headaches began around the time that he started using a new type of helmet with a tighter fit. The headaches corresponded with days in which he flew multiple flights and became worse the longer he wore the helmet. Then, around the time he started taking the prescribed medication, he coincidentally received a new allotment of personal flying clothing — including a helmet that was the correct size — for a new plane assignment. His headaches suddenly stopped.

"At that point the officer did not connect the cessation of headaches with the use of the new helmet," the doctors reported. "Reviewing the case in its entirety, the diagnosis of migraine or vascular headache was found to be incorrect; instead the individual was suffering from external compression headache due to an ill fitting helmet."

Compression headaches are caused by tight external pressure on the scalp and forehead, and they typically resolve when the pressure eases.

Doctors instructed the pilot to keep a headache diary and scheduled follow-up visits to confirm their findings. Five months later, his headaches had not returned, as he'd continued using the better-fitting helmet.

What makes the case unique: When the military doctors scoured peer-reviewed studies, they found no reports of similar instances of compression headache "in any of the Air Forces of the world," they wrote in the report.

This case, they added, emphasizes the medical significance of making sure that pilots' flight uniforms — especially their helmets — fit properly.

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!

In the late 1800s, Westminster Abbey clergy stumbled upon a mysterious sarcophagus. The lid was decorated with an 11th-century Anglo-Saxon cross, but the base had a fourth-century Roman funeral inscription. For nearly 150 years, the tomb has baffled experts, but the abbey's consulting archaeologist may have finally figured out who was buried there, according to a new study.

Westminster's chief mason unearthed the stone sarcophagus in 1869, but when experts investigated it, they discovered that the burial had been looted earlier that century. Experts also noticed that the carved decoration on the side of the sarcophagus was stylistically Roman, with a Latin inscription that can be translated as "To the memory of Valerius Amandinus. Valerius Superventor and Marcellus made this for their father." But an enormous medieval cross had been carved into the lid of the sarcophagus, suggesting that the tomb had been reused to bury an important religious figure hundreds of years later.

The mystery of the medieval individual buried in a Roman sarcophagus remained unsolved for 150 years, as no one thought that any bones were left inside. But when the stone coffin was opened for conservation in 2016 and a full skeleton was discovered, clues to the identity of the deceased finally came to light, Warwick Rodwell, the consultant archaeologist for Westminster Abbey, wrote in a study published Wednesday (Oct. 21) in the Journal of the British Archaeological Association.

Although the skeleton had been disturbed over the years, with a hole accidentally made in the skull and arm and leg bones mixed up, it was clear that the person was male, middle-aged, and of average height, bioarchaeologist James Langthorne of Pre-Construct Archaeology wrote in a 2016 report. The man also had some evidence of osteoarthritis, two healed rib injuries and gout. The bones were carbon-dated to between 987 and 1052, confirming that the Roman-era sarcophagus was reused in the Middle Ages.

"This brings us to the final question of importance: who was he?" Rodwell wrote in the study. Despite the lack of grave goods, which may have been stolen in the early 19th century, "he was almost certainly an abbot" who was given a dignified burial in a stone sarcophagus with a large cross, Rodwell wrote.

Based on the birth and death dates of the abbots of Westminster and their tenure as clergy, Rodwell narrowed the candidates down to Wulfsige (abbot from 988 to 993), Ælfwig (abbot from 993 to 1020) and Wulfnoth (abbot from 1020 to 1049). Given that Wulfsige left Westminster to become a bishop elsewhere, he was likely not buried in the abbey.

"Consequently, we have two viable contenders for the occupant of the sarcophagus," Rodwell wrote. "The fact that Ælfwig was already a monk of Westminster might favour him."

Although the final resting place of Ælfwig may have been found after a millennium, some questions remain unanswered.

For example, it is unclear why an 11th-century abbot was buried in a recycled fourth-century Roman sarcophagus. The reuse of Roman coffins is extremely unusual, Rodwell noted in the study, and nothing comparable to this sarcophagus has ever been found. One explanation for the reuse may rest with the Latin inscription, whose first word — "memoriae" (to the memory) — suggests that Valerius Amandinus was an early Christian himself. This Roman may have been a significant figure in Roman London, Rodwell wrote, but "unfortunately, nothing is known about his career."

Experts are also unsure where the Roman sarcophagus came from. It was made from limestone sourced from Oxfordshire, a county in the South of England. But perhaps the coffin was originally buried in a Roman mausoleum and they were unearthed and moved at some point, Rodwell noted. But as Rodwell pointed out in the study, "there could be a villa and its cemetery somewhere in the vicinity of Westminster Abbey, awaiting discovery."

The sarcophagus is currently on display in the Queen’s Diamond Jubilee Galleries at Westminster Abbey.

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

Some people with depression sleep far more than average, wake up exhausted, habitually stay up late, and experience mood shifts with the seasons. A new study suggests that these symptoms may cluster in a distinct subtype of depression that's tied to the body's internal clock.

While research has long linked a scrambled circadian rhythm to a risk of mood disorders, neuroscientists are now proposing that these disruptions define a specific form of depression that they call "circadian depression." First conceptualized in 2021, the body-clock subtype may affect about 1 in 4 people with severe, recurrent or persistent depression, the researchers estimate.

In their new study, published Wednesday (Oct. 21) in The British Journal of Psychiatry, the team identified the subtype in about 2,600 people out of over 11,000 evaluated.

"Circadian depression is a biologically informed subtype," said study co-author Emiliana Tonini, a neuroscientist at the University of Sydney. "Unlike subtypes defined mainly by symptoms, the core feature here is a disturbed circadian system, which common antidepressants may not fully address," Tonini told Live Science in an email.

The researchers think treatments that target the sleep-wake system, such as the sleep hormone melatonin or bright light therapy, might be beneficial for people with this subtype. However, because the subtype is still a proposal and not formally established yet, other experts say that further research is needed before the findings can inform clinical practice.

More than just bad sleep

Tonini and her team analyzed data from 11,380 adults ages 18 to 90 who took part in the Australian Genetics of Depression Study (AGDS), a nationwide study exploring how genes and life experiences influence depression and responses to treatment. They classified participants under the "circadian" umbrella if they had at least three of six features: seasonal mood swings, late sleep schedules, social jet lag (a mismatch between sleep routine during workdays and free days), night-owl habits, excessive sleep (hypersomnia), and fatigue upon waking.

A total of 2,604 people fit the proposed subtype. Compared with others in the AGDS cohort, this group was younger and developed depression earlier in life — around 19, compared with about 23 for the rest of the cohort.

The group also skewed female, and individuals reported greater psychological distress, frequent suicidal thoughts and more physical complaints than people who didn't fit the proposed subtype. Some experienced weight gain during depressive episodes and symptoms resembling hypomania, a revved-up state of elevated mood and energy that's milder than full-blown mania.

However, having this constellation of symptoms doesn't mean someone's biological clock is disrupted, said Brant Hasler, a psychologist and sleep researcher at the University of Pittsburgh who was not involved in the study. The researchers relied on the participants' self-reports of their sleep patterns; that data correlates only modestly with direct measures of circadian timing, such as measurements of melatonin in saliva, he said in an email.

"One can identify as an evening-type, and report later sleep timing, and still have physiological circadian timing that is not particularly delayed," he said.

So, in addition to checking symptoms, the team hunted for genetic clues underlying the proposed subtype. They analyzed DNA from participants' saliva samples and calculated "polygenic risk scores," which add up the influence of thousands of different genetic variants to estimate how likely someone is to develop a given condition.

"Mental health conditions are shaped by hundreds or thousands of variants that each add a small amount of risk, so everyone carries a unique 'portfolio' of risk," Tonini explained.

People in the circadian group had a higher genetic risk for depression, anxiety, attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder, the analysis suggested. They also had a greater genetic risk of higher body weight, insulin resistance, inflammation, insomnia and late-night sleep habits, compared with the other study participants.

This suggests "circadian depression is more than just 'depression with bad sleep,'" Tonini said. "It involves a mix of metabolic, inflammatory, circadian, and mood-related processes."

Could this change depression treatment?

The researchers looked at the participants' past experiences with antidepressants, finding that the circadian group reported less benefit from common medications, such as selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). Common examples include the SSRI Lexapro and the SNRI Cymbalta.

The circadian group also experienced more side effects from these treatments, such as drowsiness, nausea, anxiety and weight gain.

"If circadian disruption is a core biological mechanism in these individuals, treatments that fail to address those abnormalities may naturally be less effective," said Dr. Ruth Benca, a psychiatrist and sleep researcher at Wake Forest University School of Medicine who was not involved in the study. However, Benca cautioned that body-clock disruption may not be the only reason standard drugs fall short for these patients.

"People with more pronounced circadian disturbances often have more severe illness and other psychiatric conditions, which can contribute to treatment resistance," Benca told Live Science in an email.

Even so, tracking sleep, measurements of circadian rhythm, and seasonal shifts in mood could help clinicians identify at-risk patients earlier and select more effective treatments sooner in the course of illness, Benca suggested. "Potential approaches include behavioral routines, structured sleep schedules, or chronotherapy," in which the timing of medication or light exposure is strategically coordinated with internal body rhythms, she added.

Clinical trials are still needed to draw firm conclusions about potential treatments, Tonini noted. The findings also must be validated in broader populations, since the study drew on a single Australian cohort and its genetic analysis included only people of European ancestry.

For now, "the study is an important step toward a more personalized treatment approach," she said.

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

See how much you know about the most complex organ in the human body with our brain quiz!

Flying cars once seemed like the stuff of science fiction. But Tesla's recent demonstration, which showed the company's Rocket Roadster model briefly flying, has reignited the conversation about whether flying cars could soon become a reality.

The technology behind flying cars is continuing to advance, with companies developing vehicles that combine elements of traditional cars, helicopters, electric aircraft, and — in Tesla's case — rockets. Many of these designs use electric vertical-takeoff-and-landing technology, which allows them to lift off and land without a runway by using multiple rotors or propellers to generate lift. Advances in battery technology, autonomous flight systems and computer-assisted navigation are helping to make these vehicles seem more feasible. But challenges remain, including questions surrounding passenger safety, affordability, and the need for regulations and laws and infrastructure for the widespread use of these vehicles.

Tesla says production of its new "flying car" is scheduled for 2028, but the company is notorious for not meeting its proposed deadlines. So do you think flying cars could actually be available to the public within the next five years? Or are we still a long way from turning this science fiction fantasy into reality? Cast your vote in our poll, and share your thoughts in our comments section.

Last year's massive earthquake in Myanmar could help researchers better predict where the worst shaking will be if the "Big One" hits the San Andreas Fault in California.

The magnitude 7.7 quake hit on March 28, 2025, near the city of Mandalay and shook buildings as far away as Bangkok, 830 miles (1,330 kilometers) away. The death toll was at least 3,700 people. New research that used detailed satellite data and a one-of-a-kind video of the ground rupturing reveals that the fault had a twisty, almost helical shape, which affected the shaking.

The Sagaing Fault in Myanmar that triggered the quake is analogous to many strike-slip faults worldwide that threaten population centers, said Alice-Agnes Gabriel, a geophysicist at the Scripps Institution of Oceanography at the University of California, San Diego and co-author of the new research, which was published Oct. 14 in the journal Nature Communications. This includes California's San Andreas Fault, which is similarly tilted and likely capable of generating a 7.8 magnitude earthquake. Studying what happened as the ground ruptured near Mandalay can reveal what might occur in future earthquakes on similar faults, Gabriel told Live Science.

"The idea is, we cannot predict when and where an earthquake might happen" along a particular fault, she said, "but we may be able to predict certain aspects of it."

Gabriel uses powerful supercomputers to model earthquake scenarios, but these scenarios are only as good as the data that goes into them. In the case of the Myanmar quake, the researchers had a unique piece of data to ground-truth their model on: a security video of the ground cracking as the fault ruptured. This phenomenon had not been captured on video before.

The researchers' models revealed that the fault is not a vertical plane under the ground. Instead, the surface dips west on the northern end of the fault, becomes vertical in the middle, and then dips eastward at the southern end, they found.

In general, more shaking occurs in the direction in which a fault line dips, Gabriel said. In the case of the San Andreas Fault, the dip is inland, toward California's high desert — an area that's less populated than coastal regions on the other side of the fault. This means that, if the Big One acts similarly to the Myanmar quake, the high desert side of the fault will experience more intense shaking than the coastal side. The San Andreas Fault has also built up strain for over a century, so the researchers believe it could act in a similar way to the Sagaing Fault.

However, everyone near a dangerous fault should still prepare for major shaking, Gabriel warned, because small local variations, like how much sediment has accumulated over the bedrock in an area, can make a difference in how bad the ground movement gets. Los Angeles, for example, sits on a sediment-filled basin that would jiggle like jelly in a large quake.

The researchers also investigated whether they could have predicted aspects of the Mandalay quake from monitoring data they had available from before the quake. They knew that the Sagaing Fault had been "locked" in certain segments, meaning that while the two tectonic plates on each side of the fault were moving, the rocks at the fault line were jammed against each other. These locked segments had been accumulating strain for 186 years.

The researchers found that they could predict the path, shape and speed of the rupture on the Sagaing Fault in Myanmar with details available prior to the quake, such as the detailed shape of the fault deep underground and how long sections had been locked. Similar predictions could be made for the San Andreas and other important faults. Previous studies have also shed light on other aspects of the fault, such as its simplicity and maturity, that could inform what might happen at other faults around the world.

Researchers are currently working to update their model of what the Big One would look like on the San Andreas. The results of the update will be shared to help the public prepare, inform building codes and educate emergency managers.

"This really shows how we can use this long-term fault-monitoring data," Gabriel said.

Astronomers using the James Webb Space Telescope (JWST) have found what may be one of the most distant supernovas ever observed. And in a stroke of cosmic luck, the team thinks they're seeing what the explosion looked like just days after it ignited.

The supernova, named AT 2026abck, dates to around 1.15 billion years after the Big Bang, when the universe was less than one-tenth of its current age and bursting with massive stars flickering into life. The massive exploding star violently released its light over 12.5 billion years ago, according to the researchers — so long ago that the distance between us has effectively ballooned sixfold due to the expansion of the universe.

The discovery was described in a paper that was uploaded to the preprint server arXiv Sept. 29 and has not yet been peer reviewed. According to the study authors, this ancient speck of light is stupendously bright.

"At its peak, the supernova is about 8 billion times the brightness of the sun … almost as bright as the whole Milky Way Galaxy," study co-author Xiaohui Fan, an observational cosmologist and professor of astronomy at the University of Arizona, told Live Science via email. "Over the course of the explosion, it radiates the energy that the sun will radiate over about 2 billion years."

A beacon from the beginning of space-time

The newly discovered supernova shines brilliantly at over 30,000 degrees Fahrenheit (16,000 degrees Celsius). Its incandescent shell of ejected material has billowed to a radius of approximately 46 astronomical units ‪—‬ about 46 times the distance between Earth and the sun, or about as far as Pluto swings at its farthest point from the sun.

The supernova's host galaxy, designated ID101411, holds about 6.3 billion solar masses and is "forming new stars more than ten times faster than our Milky Way," first author Mingyang Zhuang, an observational astrophysicist at the University of Illinois Urbana-Champaign, told Live Science via email.

As with other early galaxies, ID101411 is deficient in metals, meaning any elements heavier than hydrogen and helium, because not enough time had passed to create those heavier elements in the forges of massive stars and their apocalyptic explosions.

The study authors estimate that they observed the supernova as it would have looked just four to 10 days after it exploded. Although this is relatively common, spotting one at such an incredible distance "is extremely rare," Zhuang emphasized. "You have to observe the exact same tiny patch of sky repeatedly with [JWST], and the explosion has to happen at the right moment. We were lucky."

There's another layer of luck that made the discovery even more remarkable: It was observed without the aid of a cosmological quirk called gravitational lensing — a phenomenon predicted by Einstein in which the gravity of a massive object in space bends and magnifies the light emitted by objects behind it.

"Most supernovas this far away were found with help from a massive foreground galaxy cluster acting as a natural magnifying glass," Zhuang explained. "It's the most distant one we've actually seen appear."

This supernova was discovered as part of the NEXUS Treasury program, in which JWST intermittently scours patches of the sky for ancient explosions. It had previously observed the explosion's host galaxy over the past few years and finally witnessed the supernova on Aug. 7 of this year.

An explosion in slow motion

Intriguingly, the star had not yet exploded in JWST's previous viewing, on May 28, 2026, meaning that 71 days passed on our Earthly clocks, even though only about 12 days passed in the supernova's own time frame.

This highlights a mind-bending cosmological effect: The universe's expansion doesn't just stretch space; it slows down time from our perspective.

"Because the universe has expanded since this light was emitted, everything about this explosion appears to us in slow motion, about six times slower than it actually happened," Zhuang said. "Changes that took one week at the supernova take about six weeks to unfold from our point of view."

Mysteries still remain about the nature of this ancient explosion that shone so brilliantly we can observe it across nearly the entire universe.

Rather than a conventional core collapse supernova ‪—‬ in which a star between approximately eight and 50 times the mass of the sun exhaust its nuclear fuel and suffers a rapid core collapse and subsequent explosion ‪—‬ the recently discovered supernova may be one of the universe's rarest, most powerful explosions, the study authors said. Known as a superluminous supernova, this type of explosion releases tens or hundreds of times more energy than conventional supernovas. Whether the explosion continues to heat up or starts to cool could reveal exactly what is happening in its environment and what caused it, the team said.

"Our interpretation is still preliminary," Zhuang concluded. "Follow-up observations will tell us more about exactly what kind of explosion this was."

How well do you know our home galaxy? Find out with our Milky Way quiz!

The mysterious and undeciphered Voynich manuscript has caused consternation among code-breakers, linguists and scholars of medieval literature for more than a century. But now experts think they've worked out why it's so hard to crack: It was bound incorrectly in the 15th century, meaning the pages are out of order. The new linguistic analysis of the document has moved researchers closer to figuring out what the text was all about.

The Voynich manuscript is a medieval codex made up of leaves of parchment carbon-dated to the early 15th century. Its 240 pages are covered with about 38,000 words of a unique script called "Voynichese" along with illustrations of people, plants and astrological symbols. Also known as the Beinecke Cipher manuscript, the document was initially owned by a Holy Roman emperor and was purchased by Wilfrid Voynich in 1912. Since 1969, the manuscript has been in the collection of Yale University's rare book library. Experts have unsuccessfully tried to decipher the manuscript for more than a century.

"We don't know if it's a code," Lisa Fagin Davis, study co-author and executive director of the Medieval Academy of America, told Live Science. "But there are some odd characteristics of the Voynich manuscript in terms of its physical structure."

When doing research on the number of scribes who copied the document, Davis realized from the handwriting that the manuscript's pages alternate in ways that don't make sense. In addition, she said, "there are several examples where the image goes off the page in the middle and comes out on the other side, even though there are a bunch of pages in between."

In a study published Monday (Oct. 19) in the journal Digital Medievalist, Davis and co-author Colin Layfield, an information systems researcher at the University of Malta, suggested that the inconsistent structure of the enigmatic manuscript is the result of someone mis-binding a manuscript they were unable to read.

Medieval manuscripts were made up of rectangular sheets of parchment (animal skin), typically folded in half to produce what experts call a bifolium. Around five bifolia would typically be nested together, creating what experts call a quire. Then, a stack of quires would be bound together along the spine to create a book. However, Davis and Layfield suggested that the Voynich manuscript was intended to be a stack of singulions — a series of loose bifolia never meant to be bound together as a quire or a book.

This is not the first time a researcher has suggested the Voynich manuscript has pages out of order. But Davis and Layfield analyzed the graphic properties of the untranslated document to see if their hypothesis made sense.

"We're viewing it as a text and assuming it has a message," Layfield told Live Science, which means it should be possible to statistically compare blocks of text to see if they're similar or disconnected. Layfield used a technique called latent semantic analysis (LSA), which is a natural language processing technique invented in the late 1980s to find hidden patterns in texts.

LSA is particularly useful for small sets of data, Layfield explained. "Modern AI techniques need ridiculous amounts of data to train on, which we just don't have. We've got just 35,000 or so words. That's it." The researchers' LSA analysis of the Voynich manuscript revealed that some pages had low similarity, suggesting they may not have gone together, while others had high similarity, bolstering the idea that they were supposed to be read together.

By looking at the Voynich manuscript as a collection of singulions, Davis and Layfield solved some of the nagging issues with the document.

"When you start to think about it in the context of the other strange features of the manuscript, all of those problems are resolved," Davis said. "It solves the problem of each scribe writing one sheet. It solves the problem of the images crossing the gutter."

This means that any previous work on the Voynich manuscript that assumes it was ordered correctly now needs to be reconsidered, she said, but it also means there is new progress on the book.

"This work helps us think about whether there's actual meaning underneath it all," Davis said. "It doesn't get us there," she said about a definitive translation, "but it moves the ball because you can't make sense out of a book where all the pages are mixed up."

Davis is optimistic that someone will crack the Voynich mystery, in part because a similar modern puzzle known as Cain's Jawbone has been successfully deciphered by a handful of people. This devilishly difficult linguistic puzzle from the 1930s consists of 100 pages of a murder mystery arranged in the wrong order. Due to the unique nature of the text and its vague, stylized language, even AI has failed to solve it.

"We have some ideas for other work we want to do," Davis said. For example, there's a large water stain in the upper margin of some of the pages of the Voynich manuscript. "The stain should be symmetrical from one page to the next but it's not. That also supports the idea that the manuscript is bound out of order."

Davis and Layfield are thinking about ways to compare the stain shapes across the pages, as that may help them reorder the incorrectly organized pages.

See if you know what these mysterious artifacts are with our archaeological fragments quiz!

Stimulating the brain with ultrasound could help counter the delusions people experience in schizophrenia, a small trial finds.

The trial involved transcranial ultrasound stimulation, in which a device placed on a patient's head delivers ultrasound waves through the skull and into the brain. Its goal is to change the activity in a targeted brain region.

Delusions are false beliefs that are very difficult to shake; for example, a person might believe they are being stalked when they aren't or think that a major disaster is about to occur without any evidence to suggest so. In the trial, researchers found that a 10-minute session of the ultrasound treatment reduced the severity of delusions for at least a week in patients with schizophrenia or a related disorder.

This targeted ultrasound treatment delivered directly to the brain could avoid some of the full-body effects of antipsychotic medications, such as weight gain and high blood pressure. That said, the new results, published Tuesday (Oct. 20) in the journal npj Acoustics, are a first step and will need further verification in larger trials.

"It's too early to know for certain what the therapeutic benefits will be, but it's very exciting," study co-author Dr. Donald Goff, a professor of psychiatry at the New York University Grossman School of Medicine, told Live Science.

Targeting deep brain structures

The pilot study included 10 patients with either schizophrenia or schizoaffective disorder. In both conditions, patients experience psychotic symptoms, including delusions and hallucinations. Schizoaffective disorder also includes mood symptoms, such as mania.

The researchers interviewed each participant to characterize the content of their delusions, and also documented their cognitive state and experiences with auditory hallucinations — perceptions of sounds that aren't actually occurring. The participants then received both an ultrasound treatment and a placebo treatment, spaced one week apart.

Other noninvasive therapies — such as transcranial magnetic stimulation, which uses magnetic fields — can also stimulate the brain. But the ultrasound technique differs from these therapies because ultrasound waves can penetrate deeper into the brain with greater specificity, study co-author Shy Shoham, a neural engineer at NYU Grossman, told Live Science. He compared the way a transducer directs ultrasound waves toward a given brain region with the way a lens focuses light.

In this case, the researchers focused this lens on a brain network called the cortico-striatal-pallido-thalamic circuit, which includes structures underneath the brain's outer cortex. The relationship between this circuit and schizophrenia symptoms is still somewhat unclear, partly because its deeper components are hard to study in adequate resolution with MRI, said co-author Dr. Wei Qi, a clinical assistant professor of psychiatry at NYU Grossman. However, some past studies have suggested that this network plays a part in schizophrenia.

Much of what scientists know about the network comes from research in movement disorders, such as Parkinson's disease, in which there is an imbalance between excitation and inhibition in the neurons that control movement. A similar dynamic could help to explain symptoms of schizophrenia, the scientists think.

"Our hypothesis is that, in schizophrenia, there is an imbalance between excitation and inhibition regarding what in the environment is actually important," Qi told Live Science. "The failure to inhibit irrelevant signals could be the basis of psychosis."

"Quite optimistic"

The researchers surveyed the study participants after each treatment, asking about the degree of belief each person had in their delusions and the amount of stress they caused. Compared with the placebo treatment, the ultrasound stimulation was associated with less-severe delusions over the following week. There was no significant change in patients' auditory hallucinations or overall cognition, though.

The ultrasound therapy came with mild side effects, such as fatigue and headache. Some patients had transient increases in delusions, which Qi attributed to normal fluctuations in symptoms that are expected in schizophrenia. These outcomes were just as common after the placebo treatment, so they may not be related to the ultrasound specifically.

The stimulation was aimed specifically at the right side of a brain structure called the globus pallidus internus (GPI). In a previous study, the authors found that greater connectivity between this region and another structure — the dorsal anterior cingulate gyrus — was linked to more-severe psychotic symptoms in schizophrenia. So, they made the GPI their target.

To date, "there haven't been many successful therapeutic attempts at targeting some of these deeper structures," said Dr. Deepak Sarpal, an associate professor of psychiatry at the University of Pittsburgh School of Medicine who was not involved with the study. Ultrasound waves reach brain regions under the cortex in a less-invasive manner than deep brain stimulation, in which a surgeon implants an electrode in a patient's brain, Sarpal noted.

The researchers are not the only group using transcranial ultrasound to influence the cortico-striatal-pallido-thalamic circuit. Earlier this year, another group stimulated portions of the striatum, which is located directly under the cortex, in patients with schizophrenia. They evaluated hallucinations rather than delusions, finding that the treatment reduced symptoms for at least a week after the procedure.

In this line of research, the targeted nature of transcranial ultrasound presents advantages as a research tool as well as a treatment approach.

"If we find that a specific circuit or a node in a circuit seems to be closely linked to symptoms we're trying to treat, then it will be a matter of understanding what pattern of stimulation may allow us to correct that," Goff said. Qi, Goff and colleagues now plan to continue testing their technique on more patients and to experiment with different doses of ultrasound.

"A lot more work needs to be done," Goff said, "but we're really quite optimistic about its promise."

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

See how much you know about the most complex organ in the human body with our brain quiz!

This striking satellite snap shows the scorching land and sea surface temperatures that hit Southern Europe during one of the continent's record-breaking heat waves this summer.

The image was created using data from the Sea and Land Surface Temperature Radiometer (SLSTR) on board the European Space Agency's (ESA) Sentinel-3B satellite. It was selected for this week's edition of Earth from space by Simonetta Cheli, director of Earth observation programs at ESA and head of the European Space Research Institute (ESRIN) in Frascati, Italy.

Live Science recently visited Frascati to see ESRIN's newly operational Space HPC supercomputer and sat down with Cheli for an in-depth discussion about Earth observation. When asked about her favorite satellite image, Cheli highlighted this photo as one that caught her eye this year.

In the thermal image, dark reds highlight terrestrial temperatures in excess of 95 degrees Fahrenheit (35 degrees Celsius) across most of Spain and parts of France and Italy, while dark purple spots show highs above 104 F (40 C) across patches of Spain and North Africa. The image also reveals sea surface temperatures spiking across the Mediterranean Sea. (The colors in the image do not represent the same temperatures on land and sea. For example, orange indicates temperatures of around 86 F (30 C) on land but around 73 F, or 23 C, at sea.)

Cheli said that assessing how terrestrial and marine environments interact during extreme weather events is really important and that including both in the same image is the only way to appreciate the true scale of this heat wave: "You see the red in the sea, and you see the red on the land, and I think it gives the feeling of the heat wave that we've all been living through this summer," she said.

While many people may find such images related to human-caused climate change disheartening, Cheli sees it as a sign of hope that orbiting spacecraft can monitor otherwise-invisible changes to our planet's surface in such detail.

"It makes me feel that we can do a lot about it," she said. "It makes me feel that we have tools and certainly information capabilities to support, help and also raise awareness about this topic."

Cheli told Live Science that ESA's ability to monitor extreme weather events like this will only improve as the agency launches new-and-improved spacecraft into orbit. In September, ESA successfully launched Sentinel-3C, the successor to the spacecraft that snapped this image, which has already captured its first photos of Earth and will help study future heat waves in greater detail.

Europe's record-breaking summer

Between late May and mid-August, parts of Europe were hit by at least five separate heat waves, meaning temperatures stayed unusually high throughout the season. "We had, I would say, the hottest summer ever," Cheli said.

The peak heat occurred in June, when the average temperature for that month reached 69 F (20.7 C) — its highest in Western Europe's recorded history, according to the World Meteorological Organization. (This average includes nighttime temperatures, which is why it seems relatively low compared to other temperatures mentioned so far.)

Eight countries — Austria, Belarus, Czechia, Denmark, Germany, Hungary, Poland and Slovakia — recorded their highest land surface temperature of all time at various points throughout this summer, and several others had record temperatures for a specific month or region.

The extreme weather caused widespread droughts across the continent, some of which are still ongoing, and helped trigger several wildfires, including a series of particularly large blazes in France. Experts think the high temperatures resulted in at least 35,000 excess deaths across Europe, although the true number is expected to be much higher, according to The Guardian.

The heat waves were caused by "heat domes," which are pockets of high pressure in the atmosphere that trap warm air beneath them, like placing a lid on top of a boiling pot. These are also linked to higher sea surface temperatures.

The ongoing super El Niño began in May and has already led to record temperatures in the Pacific Ocean, but it did not contribute to the European heat waves, according to ESA. Instead, the record temperatures are a continuation of recent global warming trends.

However, El Niño could lead to more extreme weather this winter, in Europe and in North America.

See more Earth from space

FRASCATI, Italy — Observing Earth from space provides a much-needed insight into the evolution of our planet's health. This is particularly important in the face of climate change, as environmental degradation, food insecurity and extreme weather events can all reveal themselves in stark images taken from high above our planet's surface.

Simonetta Cheli is the director of Earth observation programs at the European Space Agency (ESA) and the head of the European Space Research Institute (ESRIN) in Frascati, Italy. With nearly 40 years of experience in the field, she is one of the world's leading experts on Earth observation.

Live Science spoke with Cheli on a recent visit to ESRIN to talk about why Earth observation is so important, how NASA budget cuts and political changes have altered the picture, and why private space satellites risk our ability to view the planet clearly.

She also discussed how new supercomputers, like ESRIN's newly operational Space HPC, are helping to process vast amounts of data like never before — and shared her favorite recent satellite snap of our planet

Harry Baker: Why is observing Earth from space so important?

Simonetta Cheli: It's important because we need to know today what is the state of our planet, if it's healthy or if it's in danger, if it's stressed or not.

It's important to have objective information on many different variables, such as deforestation, the quality of the air that we breathe, the evolution of the oceans or the melting of ice masses. Basically, we need to be aware of what the situation is on Earth today, so we can preserve it tomorrow.

HB: How has ESA's Earth observation program changed throughout your career?

SC: When I started at ESA [in 1988], we were relying on missions from partners, including the Americans and Japanese. We didn't have our own missions.

We launched the first mission [ERS-1] in 1991. Today, just here at ESRIN, we manage over 20 missions and are planning more than 40 more. We have also launched three different missions in the last three weeks — one to look at how oceanography impacts extreme weather events [International Report for an Innovative Defence of Earth]; one to monitor the fluorescence and health status of vegetation [Fluorescence Explorer]; and one to measure temperature on land and sea [Sentinel-3C], which was a super useful thing this summer.

Europe is now a leading power in this domain worldwide. We have evolved a lot.

HB: How important is it to cooperate with other countries when observing our planet from above?

SC: Well, I must say, in ESA, it's in the DNA of our work. ESA includes 23 countries today, so we work together daily. We also work very closely with other commercial partners and the European Union, as well as international partners like NASA, Brazil, India and Africa. So this is part of our job, and very much also in the domain I'm managing.

To tackle climate and environmental stability, you cannot just do things alone at the national level. You have to share data and work with everybody in the world, where you have to have common objectives. For example, what happens to Greenland affects everybody on Earth, not just the people who live there. So the collaboration, I think, is very much inherent in our daily job at ESA and between our partners.

HB: Given the recent cuts to NASA's funding, including its Earth observation budget, does ESA feel a bigger responsibility to step up and fill the gap?

SC: I think we certainly have a bigger opportunity in the sense that today, with the systems we have and the satellites we have and the missions we have, even before the political context. For example, we were already leading the U.S. with data on emissions.

We have a very good working-level collaboration with our American partners. This is somehow preserved, although politically it is, of course, more delicate. We used to go to the climate conferences together. We are not anymore.

HB: ESA just launched the latest batch of satellites in the IRIDE constellation (an Italian funded network of Earth-observing spacecraft designed and operated by ESA). What makes these satellites so special? And how are they helping your research?

SC: We launched the latest eight [satellites] last night! (The IRIDE satellites launched on Oct. 1, the day before this interview took place.)

Sixty-eight satellites are planned overall in this constellation, and we have launched quite a few [39] already, and plan to launch some more before the end of the year.

The network will collect a lot of data from the optical radar spectrum that will support different user needs: for example, in the civil protection area, in coastal erosion monitoring, in coast guard operations and in environmental stress analysis. And so this system will certainly be a big contribution to the wider European Earth observation setup.

HB: The number of private satellites, like in SpaceX's Starlink constellation, is increasing fast. Are you worried about the impacts that this might have on your scientific spacecraft?

SC: We are worried because we see that the anti-collision maneuvers are increasing and increasing. When my mission manager tells me we have to move the satellite because there is a risk of collision with another satellite, we have to go check with ESO [European Southern Observatory] in Germany, and then the operations center moves the satellite. And the number [of times we've done this] has certainly increased in the last four or five years due to the increased number of satellites up there.

For the moment, the technical collaboration with partners is going quite well. So when we see someone else's satellite, we actually try to organize things as best we can, and technically it's working well. But what we need for the future is a clear framework at the legal level, which is engaging everybody.

"Everybody" in space is no longer only the institutional partners; it's not just the space agencies of the world that should engage. Today, you have private actors, like Starlink, and if they don't engage in the same rules, you risk having a delicate situation. But this is something that we are discussing daily, and we're tackling.

HB: The whole point of Earth observation is to protect our planet. How do you feel about some of the negative impacts of launching satellites, such as exhaust plumes, metal pollution and space junk?

SC: There is a very strong objective linked to sustainability at ESA. It is not just about using the data to better preserve our planet; it's also about being sustainable in the daily work we do.

This is linked to, for example, trying to have a space debris policy; trying to have enough propellant on board of the satellites that we build to make sure that once they finish their lifetime, they come back with a re-entry assist and they don't stay there in orbit. And the same is true in the launcher domain, where there's a very strong effort from our partners in French Guiana [where ESA's only active launch site is located] to lessen our impact as much as possible on the environment with the launch setup.

There's a really dedicated team doing all this.

HB: How will AI systems and advanced computers, like Space HPC, help researchers process data? And what sort of things could that help you do?

SC: We have today a wealth of data that is continually increasing. Just in the Copernicus program [Europe's biggest Earth observation initiative], we receive 500 terabytes of data per day.

We also have big volumes of data in the archives here at ESRIN from science missions of international partners, including Japan, India, the U.S. and others. This "heritage data" guarantees that archival data of missions that have ended are preserved, which is super important.

So instruments like SpaceHPC, which have high computing capability, help us a lot to process those datasets faster.

HB: What is your favorite satellite photo of Earth?

SC: I have too many favorite satellite photos, I must say. But this summer, the one I really found striking was a thermal image of Europe's heatwaves because, in that image, you see that the temperature on land and on sea was increasing so much.

It was captured by Sentinel-3B [a predecessor of the recently launched Sentinel-3C], and you see the red in the sea, and you see the red on the land, and I think it gives the feeling of the heat wave that we've all been living through this summer. We had, I would say, the hottest summer ever.

But it makes me feel that we can do a lot about it. It makes me feel that we have tools and certainly information capabilities to support, help, and also raise awareness about this topic.

So right now that is a favorite, but there are so many [other photos].

This interview has been condensed and edited for clarity.

One of the best fall meteor showers peaks this week, when pieces of the famous Halley's Comet streak across Earth's atmosphere as fast-moving "shooting stars."

The Orionid meteor shower will peak overnight Wednesday (Oct. 21) through Thursday (Oct. 22), potentially producing around 20 meteors per hour under a dark sky, according to Time and Date. The Orionids are caused when Earth passes through the debris left by Halley's Comet, which last passed through the inner solar system in 1986 and will return in 2061.

Halley's Comet is presently beyond the orbit of Neptune, according to The Planets Today, but it doesn't need to be close to Earth to cause "shooting stars." Every time the comet travels through the inner solar system, heat from the sun causes it to shed dust and rocky particles along its orbital path. Earth's own orbit takes the comet through streams of that ancient debris several times a year, with the particles vaporizing as they slam into our planet's atmosphere.

The Orionids are particularly fast meteors, striking Earth's atmosphere at around 41 miles per second (66 kilometers per second). They can produce bright streaks, occasional fireballs (extremely bright, sometimes colorful meteors) and "persistent trains" — glowing trails that remain visible briefly after a meteor has disappeared. The best way to view them is with the naked eye, although a nice pair of stargazing binoculars or a small backyard telescope will help you enjoy more sights during peak skywatching season this fall.

Halley's Comet produces not one but two annual meteor showers. Its orbit comes close to Earth's at two different points, so our planet encounters the comet's debris twice each year — once during the Orionids in late October, and again during the Eta Aquariid meteor shower in early May.

There's a slight complication with the Orionids this year. A 71%-illuminated waxing gibbous moon will brighten much of the night, making it harder to spot meteors. However, the moon will set early Thursday morning, creating a valuable window of darkness before dawn. That's also when the constellation Orion will be high in the sky, making the predawn hours the best time to watch.

You can trace the paths of Orionid meteors back to their radiant: the famous red supergiant star system Betelgeuse in the constellation Orion. (That's why the shower is called the Orionids.) However, there's no need to look directly at Orion. Meteors seen farther from the radiant can produce longer streaks across the sky; each one comes from a tiny piece of Halley's Comet completing a journey that began many centuries ago.

Archaeologists have unearthed an 11th-century wooden kitchen gadget with an ancient board game carved into the back. Medieval bakers may have used the wooden paddle not just to transfer bread into an oven but also to pass the time while they waited for the food to cook, the researchers said.

"We discovered a fragment of a fairly large shovel," Sergey Toropov, director of Novgorod State University's Center for Archaeological Research, said in a translated statement. "Most likely, it was a bread shovel, which was used to bake bread in an oven. On the reverse side, however, three squares have been carved, one inside the other."

The "bread shovel" — also known to contemporary home bakers as a wooden bread peel, a pizza paddle or a pizza peel — was found at the archaeological site of Pyatnitsky in the center of Staraya Russa, a medieval town between Moscow and St. Petersburg where last month, archaeologists reported their discovery of a "snake amulet."

The preserved portion of the bread peel measures about 12 by 16 inches (30 by 40 centimeters), and it was likely crafted from oak. While one side is flat, likely for baking tasty treats, the other side had been carved with a board for the ancient game known as merels, merrelles, mills, nine-men's morris or cowboy checkers.

The origin of the game is unknown, but historical records and archaeological artifacts suggest a similar two-person logic game was played by the ancient Romans two millennia ago — and the game may be even older than that. In the Middle Ages, merels became particularly popular across Europe and Asia, possibly because it requires little equipment and can be set up quickly.

A typical merels board has three nested squares connected by horizontal and vertical lines. Each player has nine pieces of the same color. The goal is to arrange the pieces into columns of three along the lines. When a player forms a line, they can remove any one of their opponent's pieces. In this way, merels is a mixture of tic-tac-toe and checkers. A player wins when their opponent has only two pieces left or is completely blocked. (You can play an online version here.)

"Perhaps special boards for playing merels existed in antiquity," Toropov said, "but more often, one finds playing boards scratched or carved into the flat surfaces of household objects."

The archaeologists are not sure whether the wooden bread peel served two functions or whether it was repurposed as a game board after it broke and was no longer useful.

"At any moment, one could mark out a board on a flat surface, find suitable pieces — for example, small stones lying underfoot, and while away some time," Toropov said.

Merel boards and playing pieces have been recovered from ninth-century archaeological sites in the kingdom of the Rus', whose ancestors were Vikings who arrived in what is now Russia in the eighth century, according to the statement, but "a find as well-preserved as the one from Staraya Russa is practically unique."

A gene variant called APOE4 dramatically increases the risk of late-onset Alzheimer's disease, the most common form of dementia. Now, emerging research is revealing APOE4's true role in the condition, and a new study pinpoints a possible way to treat it.

Historically, scientists studying Alzheimer's disease have focused on two proteins that accumulate in patients' brains: amyloid-beta and tau. However, there's a "third thing that people didn't pay attention to, until recently," said study co-author Li-Huei Tsai, a neuroscientist at MIT. That third thing is the accumulation of droplets of fat, or lipids, in the brain, she told Live Science.

The APOE gene makes proteins responsible for transporting fat around cells throughout the body and brain. A version of the gene called APOE4, which increases the risk of late-onset Alzheimer's three- to 12-fold, makes proteins that are less efficient at this function, Tsai said. But how APOE4 affects different brain cells was not clearly understood.

Tsai's team has been working to close that gap for about a decade.

"APOE4 can influence many different cell types," she emphasized. "It's not just one cell type."

Zeroing in on the clues

In past laboratory research, Tsai's team found that APOE4 causes a buildup of cholesterol in astrocytes, star-shaped brain cells that support the function of neurons. Genetic analyses suggested that the gene variant may mess with how these cells process fat.

Another study zoomed in on oligodendrocytes, cells that help insulate neurons' outgoing wires with a fatty material called myelin. This material helps neurons send messages more efficiently. APOE4 caused the oligodendrocytes to accumulate cholesterol. So, in lab mice, the team used a drug to help the cells get rid of that extra cholesterol, and it improved the cells' ability to make myelin and the mice's performance on cognitive tests.

In their latest research, published Thursday (Oct. 15) in the journal Cell Stem Cell, Tsai's team dug into the question of why APOE4 causes fat to accumulate in the first place.

They used stem cells to grow APOE4-carrying oligodendrocytes and then turned specific genes on or off, to see if they increased or decreased the formation of fat droplets. This screening pointed to a major group of genes involved in cell-to-cell communication, called the Wnt signaling pathway. This included a key gene called DKK1, which acts as a brake on this signaling system.

Disabling DKK1 — essentially lifting the brake — reduced the concentration of fat droplets in the cells, the team found.

In brain tissue samples from organ donors with APOE4, the team also found signs of low Wnt signaling. This finding "establishes a very strong link" between the signaling pathway and formation of fat droplets, said Rosie Jackson, a cell biologist at the University of Dundee who was not involved in this study.

APOE4's effects across the brain

The researchers then investigated exactly how Wnt signaling was disrupted in oligodendrocytes.

APOE4 seemed to decrease the cells' supply of a protein that helps relay Wnt signals. That helpful protein was being broken down by an enzyme whose levels had been boosted by the APOE4. In mice, the team used a drug to block that extra enzyme, and the treatment ultimately restored normal Wnt signaling, reduced fat buildup, and helped the cells make myelin properly.

This could change how scientists think about treating Alzheimer's disease, Jackson said. It "opens up a new wave of potential therapeutics" that could target the accumulated fats, rather than going after only amyloid-beta and tau, she said.

"I think that this is becoming a really common idea in the field — that we're going to need multiple medications that target slightly different elements," she told Live Science. "And targeting lipids will be a really important part of that."

That said, the findings have not been confirmed in humans yet.

"It's very encouraging that facilitating lipid clearance and lipid movement is a potential therapeutic avenue," said study co-author Joel Blanchard, a neuroscientist at the Icahn School of Medicine at Mount Sinai. The question is how we can do that in a safe and effective manner in humans, he said.

Blanchard has led other research that underscores APOE4's effects beyond fats and myelin. The gene variant may affect cells that support blood vessels in the brain by driving scarring and contributing to amyloid-beta buildup. It may also mess with the "trash collectors" inside astrocytes, again leading to a buildup of harmful proteins.

While cells with other versions of the APOE gene can put a lot of energy toward breaking down the proteins, APOE4-carrying cells put all their energy toward fat storage, Blanchard said.

But more research is needed to understand how to fix the problem, he said. Hopefully, targeting fat storage "could rescue not just one thing but multiple things that go wrong in the course of Alzheimer's disease," he told Live Science.

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

A drone powered by artificial intelligence (AI) has completed a championship race course faster than some of the world's best human drone pilots.

In a study published Oct. 14 in the journal Science Robotics, scientists created an AI system capable of pushing a quadcopter through a demanding course at over 60 mph (100 km/h), using little more than a single forward-facing camera, an inertial measurement unit, and a tiny onboard computer.

The system, called MonoRace, even won the 2025 Abu Dhabi Autonomous Racing League drone racing competition, outperforming every rival autonomous team and posting faster times than three former human world-champion drone pilots.

MonoRace accomplished this without the aid of GPS, external motion-capture systems, stereo cameras, or a preloaded map of the course. The system is an onboard autonomous flight model created by researchers at the Delft University of Technology's Micro Air Vehicles Lab in the Netherlands. Its name reflects its central design feature; "mono" refers to its monocular vision. The drone relies on a single rolling shutter camera and monitors its own motion with an internal measurement unit (IMU) that gauges acceleration and rotation.

Flying at breakneck speeds

The limited sensor package feeds a neural network, a machine-learning model that uses interconnected artificial neurons to learn patterns from data. This neural network identifies racing gates and estimates the drone's position and motion to generate motor commands. Then, it sends the commands to the four propellers at a rate of 500 times per second through the drone's flight controller.

The system fits a drone that weighs a mere 966 grams (2.13 pounds) and measures approximately 11.8 x 11 x 3.9 inches (30 x 28 x 10 centimeters). Because the MonoRace hardware was so compact, lightweight and computationally efficient, the team was able to operate it entirely aboard the drone.

On the Abu Dhabi course, MonoRace completed two laps around 11 gates in 16.56 seconds, hitting a top speed of approximately 63 mph (102 km/h).

A recently released video tracks MonoRace's development and performance in the competition, with real flight sequences demonstrating how the drone banks sharply, accelerates through gates, and navigates a course without human assistance.

However, some of the sequences are computer-generated. Study co-author Guido de Croon, a professor at the Delft University of Technology, said those are intentional visual effects. The only fully simulated imagery appears at about the two-minute mark, during the segment showing the training process.

"Here we show the gates in a visual simulator for the video but the real training happened in a stripped-down, pure physics simulator that ran really fast," de Croon told Live Science in an email. "Simulating vision was not done during training, as the control neural network receives an estimated state as input, which comes from a different perception and state estimation process."

The rest of the footage is real, although some shots include overlays showing how the drone interprets its camera feed. A convolutional neural network segments the white gates, sometimes displaying them as red in the normal camera image. Small circles mark detected gate corners, red lines indicate gate edges, and a blue overlay shows the portion of the image where the drone expects to find the next gate.

How the AI learned to race

Scientists trained the MonoRace model with reinforcement learning, a machine learning method in which an agent repeatedly attempts a task and receives feedback based on its success or failure.

"The reinforcement learning ran in simulation, because it needs lots of trial and error — like millions of tries," de Croon said. "It actually learns to fly from scratch."

The network learned to translate the drone's position on the track, velocity and orientation directly into motor commands. According to de Croon, early training focused on the basics, like avoiding crashes and reaching the first gate. As the training progressed, the system learned to advance farther along the course and fly at higher speeds.

The researchers didn't train the system on a single aircraft. Instead, they varied dimensions such as weight, voltage, drag, sensor noise and propeller condition so the AI model could cope with real-world variations and imperfections.

"That ensures that the trained network can control different drones," de Croon said.

MonoRace could become a training tool for human drone pilots, "a bit like powerful chess programs have also inspired humans playing the game," de Croon said.

Its broader significance lies in demonstrating advancements in physical AI, especially how a robot can perceive, decide and act at high speeds despite limited sensing and computing power. The control network runs on a microcontroller-class chip, meaning that sophisticated control doesn't require a large computer.

De Croon noted that a similarly sized network could optimize for minimal energy use rather than minimum lap time. Because most machines rely on small processors and conventional controllers, energy-optimal neural control could eventually reduce power consumption in everyday robotics, he said.

Tesla has unveiled a new "flying" version of its Roadster electric vehicle (EV) that uses SpaceX tech to pull off seemingly impressive airborne acrobatics.

During a filmed demonstration at the SpaceX rocket testing facility in Texas Thursday (Oct. 15), the second-generation Tesla Roadster was shown accelerating up a curved ramp before launching itself into the air, performing a 180-degree barrel roll and touching back down to Earth.

In another stunt, the vehicle leapt over a row of parked Teslas. For safety reasons, the vehicle was operated remotely in both instances.

"Turns out, the future does have flying cars," Tesla and SpaceX CEO Elon Musk wrote on X following the demonstration.

The Roadster's airborne capabilities are made possible by a system of cold-gas thrusters developed using technology from Musk's aerospace company, SpaceX. These thrusters release bursts of high-pressure gas to generate thrust, allowing the vehicle to accelerate rapidly and, according to Tesla, become airborne for short periods.

The new Roadster will come in three variants: Performance, Thrust and Rocket. Only the Rocket is capable of flight. The Performance model is a two-seater equipped with a suction system that's designed to improve traction and handling (or drive up inverted ramps, as in Tesla's demo), while the Thrust model adds rear-mounted thrusters that Tesla claims can propel the vehicle from 0 to 60 mph (97 km/h) in under a second.

The highest-end model, Rocket, features SpaceX cold-gas thrusters positioned around the vehicle to enable short bursts of flight and in-air control. This single-seat model will be available by invitation only, according to Tesla.

On the company's website, Tesla representatives explicitly stated that the Rocket isn't approved for use on public roads and that availability depends on regional regulations. During the reveal, Musk told the audience that the Rocket "is not necessarily a safety-optimized car."

Tesla hasn't disclosed how far or for how long its EV can remain airborne, nor is it the first company to develop a hybrid road-air vehicle. There is also skepticism from outside viewers on whether the demonstration could be replicated outside of controlled scenarios.

Artificial intelligence (AI) scientist Yann LeCun ‪— a professor of data science, computer science, neural science and electrical engineering at New York University ‪— described the demonstration on X as a "marketing stunt" and questioned whether the vehicle would work in practice.

"Even assuming that 50% of the mass of the car is the compressed air, that gives you less than 10s of useful thrust (with thrust-to-weight ratio larger than 1.0). Probably more like 5 seconds, actually," he posted on the social media platform. "So the car must be an empty, lightweight shell containing big compressed air tanks. Cute demo, but totally impractical. But of course, you knew that."

He likened it to SpaceShipOne, which debuted in 2004 as the first privately funded spacecraft and made three record-setting flights before being retired.

California-based Alef Aeronautics, which is developing its own flying EVs, marked Tesla's unveiling by releasing footage of its vehicle flying over an earlier Roadster model. Alef representatives said the demonstration marked its 1,000th logged flight.

"Welcome Tesla to the flying car race, we've been here alone for eleven years," Alef CEO Jim Dukhovny said in a statement emailed to Live Science. "Having competition is a good thing, especially from such a major company as Tesla."

Unlike Tesla's compressed-gas tech, Alef's vehicle uses electric propellers for vertical takeoff and landing, with a rotating cabin and body designed to support forward flight.

Production of the new Roadster is scheduled for 2028, but Tesla doesn't have the best track record of meeting its deadlines. The company has delayed production of its Optimus humanoid robot a few times since first unveiling the machine in 2021, for example, with an initial start in 2023, before being pushed back. Only in recent months has production begun to scale to a few hundred units per week.

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Archaeologists have unearthed a Roman military camp in Spain, where they found fragments of weapons and metal tacks from soldiers' shoes. The camp was used during the Cantabrian Wars fought by Emperor Augustus as he expanded the Roman Empire in the first century B.C.

The fortified military camp is made up of an earthen platform roughly 39 feet (12 meters) wide, which is surrounded by a stone perimeter wall about 5 feet (1.5 m) thick, according to a translated statement. Uncovered during excavations earlier this year, the camp is situated about one-third of a mile (500 m) from where an Iron Age settlement was once inhabited by the Cantabri people, a group of Celtic tribes that lived among the Cantabrian Mountains in modern-day northern Spain.

The Cantabri fiercely resisted Roman rule for a decade, but in 19 B.C., they were conquered by the military commanded by Emperor Augustus. The Cantabrian Wars marked the end of local control over the territory, as the Iberian Peninsula then came under control of the Roman Empire.

"It's not easy to find a camp associated with a hill fort in this condition," Eduardo González Gómez de Agüero, an archaeologist at the University of León who co-directed the excavation project, said in the statement.

Among the well-preserved remains at the camp were metal weapon fragments and small iron tacks known as hobnails, which were hammered into the bottom of Roman soldiers' leather military sandals to help provide traction on rocky and muddy terrain. These objects are evidence that the Roman military was prepared to attack and subdue the Iron Age community, according to the statement.

The archaeologists also uncovered evidence of a major fire that destroyed most of the pre-Roman settlement, including two temples. González Gómez de Agüero suggested that the Romans may have deliberately set the fire as part of their conquest.

"It's not just about defeating the enemy, but about humiliating them, erasing their identity, and breaking their connection to the land," he said in the statement.

Researchers are still working on establishing the chronology of the Romans' final attack on the Cantabri and want to understand if the settlement was destroyed in a single event or over time. Previously, another research team found 66 Roman camps in northern Spain, showing the immensity of the empire's attacks against the Cantabri.

The latest find is helping researchers understand the scale and location of Rome's fight for control of the Iberian Peninsula.

"It is an important step in understanding how the conquest was carried out on the Cantabrian slope of León, an area where it was necessary to link the Roman camps with Iron Age settlements," Carlos Fernández Rodríguez, an archaeologist at the University of León, said in the statement.

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

This copper plate was discovered in the late 19th century in a prehistoric Native American burial at the Etowah Indian Mounds archaeological site in Georgia, but it was likely made hundreds of miles away at Cahokia Mounds in Illinois. While the decorative plate showcases long-distance trade and a shared ritual culture among early Indigenous groups in the southeastern United States, the nature of the human figure depicted on the artifact has been debated for over a century.

The "Birdman" relic is one of two hammered copper plates that Smithsonian archaeologist John P. Rogan unearthed in the 1880s while digging in a burial mound at Etowah, a centuries-old village occupied by thousands of Native Americans from 1000 to 1550. Etowah was part of the "mound-building," or Mississippian, phase of Indigenous occupation; other famous sites include Moundville in Alabama and Cahokia in Illinois. These groups had extensive trade networks and shared a common artistic and ceremonial tradition known as the Southeastern Ceremonial Complex.

This copper artifact, known as Rogan Plate 1 or the "Birdman" plate, is in the collection of the Smithsonian National Museum of Natural History in Washington, D.C. The plate is roughly 11 inches (28 centimeters) tall and had been buried with a high-status person who likely died at Etowah in the mid-14th century. But experts believe the copper plate was an heirloom made decades earlier, at Cahokia, and traded south to Etowah.

A human figure dominates the copper plate with its elaborate bird costume. The person carries a severed head by the hair in their left hand, while their right hand holds a club or mace. The figure also wears a pleated skirt or loincloth that may have been made from human scalps. This bird-human figure is commonly depicted in the Southeastern Ceremonial Complex and has been called a dancing warrior, eagle warrior, eagle dancer, hawk dancer, falcon dancer and falcon warrior. But more often, the figure is called Birdman or Morning Star, a prehistoric Mississippian hero associated with agriculture and rebirth.

Archaeologists' interpretations of the Birdman plaque from Etowah have long assumed that the represented figure is a male warrior. In a 2004 study, for example, archaeologist Adam King wrote that "this plaque would have served as an emblem of office awarded to a chieftain, and would have accompanied him as a sign of his strength among the ancestral spirits."

But the sex of the skeleton in the Etowah burial is unclear, and there were high-status graves of both men and women at Etowah, archaeologist Billie Follensbee and art historian Katie Buford wrote in a 2017 study. Although experts previously assumed that both Rogan Plate 1 and Rogan Plate 2 represented male warriors, Follensbee and Buford found that the figures have slender bodies with prominent right breasts, suggesting the "Birdman" may have actually been female.

"A female bird-human warrior could have represented a gender variant individual in the form of the well-known Native American phenomenon of the 'manly-hearted woman,' a woman who has assumed the usually male role and the garb of a combat soldier," Follensbee and Buford wrote. In addition to the historic term "manly-hearted woman," third-gender or gender-variant individuals in Indigenous North America are often referred to as "two-spirit," a broad term Indigenous people coined in 1990 to describe people who take on gender-nonconforming roles.

The commemoration of a two-spirit individual on a copper artifact, as well as the use of the artifact as a high-status grave good, "not only demonstrates the Native American cultural acceptance of such gender variant roles but also further serves to celebrate the elite status and achievements of these 'manly-hearted women,'" Follensbee and Buford wrote.

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

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Rising temperatures around the globe are contributing to a range of health risks, from infectious disease to food insecurity and wildfire smoke. Extreme heat is another major public health concern, as climate change drives up both average temperatures and the frequency of extremely hot days. This August was the world's hottest on record, and it drove upticks in heat-related emergency visits and deaths in various U.S. states.

Hotter weather is expected to pose dangerous health risks for millions, and pregnant people are especially vulnerable to its impacts, experts caution.

"Pregnant people are physiologically more vulnerable to heat," Dr. Susanna Esposito, a pediatrician at the University of Parma in Italy, told Live Science. "Climate adaptation should treat pregnant people as a priority population."

Extreme heat is linked to adverse birth outcomes that can be fatal for both mothers and newborns. Heat can also hinder fetuses' development, contributing to long-term health and cognitive effects.

Scientists and public health experts are working to identify the thresholds between safe and dangerous heat for maternal and prenatal health. As the planet warms, how will that affect the risks associated with pregnancy? And how can those risks be countered?

Low birth weight

When the body tries to cool down, blood moves to the extremities to dissipate heat through the skin's surface. Some studies suggest that, in a pregnant person, this may reduce blood flow to the placenta, which in turn reduces the organ's supply of oxygen and nutrients. This is thought to contribute to low birth weight, which is associated with a heightened risk of illness and death shortly after birth, as well as cognitive and mental-health challenges later in life.

Heat stress may also spike the body's levels of cortisol beyond what they should be in a healthy pregnancy, studies in lab animals suggest. This may expose developing fetuses to more cortisol than usual, affecting some aspects of development and functions of the placenta. This mechanism is not fully understood in humans yet, though.

That said, several studies in humans support the notion of a link between heat exposure and low birth weight. Mothers who were pregnant during a 2003 heat wave in France were more than twice as likely to have a baby of low birth weight than mothers whose pregnancies did not coincide with the extreme heat. The trend was especially strong when the heat wave hit during a person's first trimester.

In a study conducted in Arizona, hotter temperatures during the third trimester were also associated with lower birth weight, said study co-author Kristin Mickelson, a social-health psychologist who studies public health at the Arizona State University.

Preterm and early birth

Preterm delivery — before 37 weeks of gestation — is one of the most concerning health outcomes that's been linked to heat, Esposito told Live Science. The risk of neurological and developmental disabilities is higher in preterm babies than in full-term babies.

"If you're born preterm, you have a heightened risk of all sorts of adversities throughout infancy, but then also extending into childhood and even longer term," said Clara Heil, health researcher at Lund University in Sweden.

Severe heat may make preterm birth more likely. A review of 70 studies suggests that the chance of preterm birth is 16% higher when a multiday heat wave hits during the final weeks of pregnancy. Regarding average temperatures across an entire pregnancy, each additional 1.8 degrees Fahrenheit (1 degree Celsius) boosts the risk of preterm birth by 5%, the same review found.

High temperatures have also been tied to early births, which occur after 37 weeks of pregnancy but before 39 completed weeks. Early birth is associated with an increased risk of hospitalizations through childhood and slower neurologic development.

A study analyzing 56 million U.S. births across two decades suggested there was about 1 more early birth per 100,000 pregnancies on days with a maximum temperature above 90 F (32.2 C), compared to 60 to 70 F (15 to 21 C). Deliveries on hot days were typically about six days earlier than anticipated, but some were up to two weeks early.

With average temperatures continuing to rise, early and premature births could become more common. The United Nations predicts that the world is set to cross the 1.5 C (2.7 F) threshold of warming compared with pre-industrial levels, likely within the next five years, and we may even surpass the 2 C (3.6 F) threshold in that timeframe.

"We can probably expect to see these temperatures, or worse, in the upcoming years," Lizbeth Burgos Ochoa, statistician at Tilburg University in the Netherlands, told Live Science.

Preeclampsia, heart defects and other risks

Maternal heat exposure has also been associated with an increased risk of preeclampsia, a pregnancy complication related to blood pressure that can be fatal. In a 2011 study conducted in France, hotter temperatures during the first trimester were associated with a slightly increased risk of severe preeclampsia, although more research is needed to understand why.

Heat exposure has also been linked to other conditions of pregnancy, including gestational diabetes and hypertension, as well as increased emergency hospital admissions during pregnancy, overall.

Additional studies have highlighted potential risks for developing fetuses and newborns. For example, following a heat wave in Canada, the risk of a baby being born with critical heart defects was 6% higher, one study found. Babies with the highest risk had been exposed to temperatures of 86 F (30 C) or higher for at least 15 days during the first trimester of pregnancy.

Extreme heat waves may also raise the chance of stillbirth, according to a study conducted across six U.S. states. Four consecutive unusually hot days — exceeding the 97.5th percentile of temperature for a given county — in the last week of pregnancy was linked to a 3% increase in the risk of stillbirth.

These studies are observational, so they show links between heat and pregnancy outcomes but cannot directly show that the heat spurred the increased risks. They also don't take into account study participants' home environments or strategies for cooling off, so they don't provide a full picture of how much heat they were exposed to.

Caring for pregnant people and the next generation

Researchers are still working to understand what temperatures pregnant people should be most concerned about.

"It would be [helpful] to understand what level of heat becomes dangerous to women," Heil said. "Is there a threshold where it becomes difficult for the body to dissipate heat? And especially for the pregnant body, which is different from the non-pregnant body, to cope with that heat?"

Heil and her research team synthesized over 100 studies on heat and poor birth outcomes, such as stillbirth, preterm birth, placental abruption and preeclampsia. The studies varied considerably in that they covered different timeframes, focusing on just one trimester or all three, for instance. But in general, their results converged on a pattern: The risk of poor outcomes rose as temperatures hit about 87 F (30.5 C). At 102 F (39 C), the combined risk of poor outcomes rose by 20%.

This summer, daytime maximum temperatures in the continental U.S. averaged a record-breaking 88.6 F (31.4 C). The number of days per year over 105 F (35 C) is expected to triple in the U.S. by midcentury.

Heat's detrimental effects on birth outcomes are even more extreme for those with disadvantaged socioeconomic conditions, Burgos Ochoa noted. People with lower incomes are less likely to have air conditioning, and neighborhoods with a lower median income tend to have less green space, which contributes to trapped heat in their immediate surroundings. Expanding green spaces and adding bodies of water can help cool down neighborhoods and mitigate heat impacts on health, she said.

Heil's research team has developed a phone app for pregnant people and those who have recently given birth that forecasts the risk of heat stress and suggests actions to take to mitigate those risks, such as hydrating or changing clothing. Heil is hopeful that the app and similar early-warning systems can make a difference.

"Maternal health should be at the top [of our concerns], because it is about the next generation," Mickelson said. "If we don't take care of the mothers that are giving birth to the next generation, that's going to have long-term consequences down the road."

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

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Aging is one of the biggest risk factors for developing glaucoma or cataracts — but as scientists look more closely at what happens to the eyes over a lifetime, they are finding that people's exposure to air pollution also plays a role in whether they develop these eye conditions.

Glaucoma, which affects about 80 million people worldwide, is a group of diseases that damage the optic nerve, which carries visual information from the eye to the brain. It can lead to permanent vision loss, usually affecting peripheral vision at first and later central vision. Cataracts are even more common, affecting more than 94 million people globally; the condition occurs when the eye's lens becomes cloudy, causing blurred vision and, eventually, blindness.

Aging raises the risk of both diseases, as do certain medical conditions, such as diabetes. But now, a review of 41 studies suggests that people who are exposed to higher levels of air pollution may also face a greater risk of these diseases. The research, presented in September at the 44th Congress of the European Society of Cataract and Refractive Surgeons in London, brought together evidence from dozens of studies collectively involving millions of people across East Asia and the U.K.

The studies were observational, meaning they can only draw a link between air pollution and the eye conditions, rather than prove that air pollution causes the diseases. But still, "this reframes glaucoma and cataract as conditions shaped by where you live and breathe, not just how long you've lived," said study co-author Dr. Ahmed Alnabihi, an ophthalmologist at King Khaled Eye Specialist Hospital and Research Center in Saudi Arabia, who presented the findings. These environmental exposures may compound age-related decline in the eye as they do in cardiovascular disease, he said.

PM2.5 shows the clearest links

The researchers examined exposure to several pollutants, including different sizes of particulate matter (PM), such as fine PM2.5 and larger PM10. They also looked at nitrogen dioxide, sulfur dioxide, ozone and carbon monoxide.

Most studies included in the review estimated people's long-term exposure based on the pollution levels around their homes and in their communities. They used a range of methods, including government monitoring systems, satellite data and computer models designed to estimate pollution levels. A few studies examined short-term exposure and its relation to more sudden eye issues, such as acute angle-closure glaucoma, a medical emergency that can quickly cause vision loss.

Using this wealth of data, the team compared pollution exposure with rates of glaucoma, cataracts and age-related macular degeneration (AMD), another common eye condition that impairs vision. PM2.5 — tiny particles that measure 2.5 micrometers or smaller — showed the clearest associations with glaucoma and cataract risk.

People with the highest exposure to PM2.5 had 70% higher odds of glaucoma, compared to those with the least exposure. Plus, an increase in PM2.5 exposure equivalent to the difference between the 25th and 75th percentiles of exposure within each study was associated with 8% higher odds of glaucoma and a 4% higher hazard of cataracts.

The evidence was less consistent for air pollution and age-related macular degeneration, which damages the central part of the retina that's responsible for sharp, detailed vision. And unlike the clear connection seen with PM2.5, other pollutants showed less consistent links to eye disease. For instance, nitrogen dioxide was not significantly tied to AMD, ozone was not tied to cataracts, and neither pollutant was linked to glaucoma. Sulfur dioxide and PM10 showed no significant associations with any of the three conditions.

The association between PM2.5 and glaucoma was relatively consistent across the reviewed studies, said Nidhi Singh, an environmental epidemiologist at the IUF-Leibniz Research Institute for Environmental Medicine in Germany, who was not involved in the study. The findings for PM2.5 and cataracts were moderately consistent, albeit more variable than the glaucoma data; still, she said that the analysis seems to support a link.

Singh did caution that the underlying evidence is observational. "Therefore, the results demonstrate an association, not by themselves a causal effect of PM2.5 on glaucoma or cataract," she told Live Science.

What explains the increased risk?

The exact biological mechanisms behind these links remain unclear, but Alnabihi noted that fine particulate matter is small enough to be absorbed into the body. This can trigger oxidative stress, in which harmful molecules overwhelm natural defenses and cause damage. It also drives chronic, low-grade inflammation, in which the immune system stays mildly activated for long periods, he explained.

In the eye's lens, these processes can "damage the crystallin proteins that keep it transparent, causing them to misfold and cloud, which is what a cataract is," Alnabihi said.

In the optic nerve, the same processes are thought to damage retinal ganglion cells, a special type of neuron that relays information from the retina to the brain. This can contribute to glaucoma independent of internal eye pressure, he said, which is another big risk factor.

"Unlike the lungs or gut, its [the eye's] surface is in direct, continuous contact with outdoor air, giving pollutants a uniquely direct route that might cause damage," he added.

Other studies have found clues that support the link between PM2.5 and eye damage. Mice that were exposed to ambient PM2.5 for nine months developed elevated pressure inside their eyes, a glaucoma risk factor. The researchers observed both oxidative stress and nitrative stress — a similar phenomenon — in the tissues that drain fluid from the eye, which may help to explain the rise in pressure.

Studies of humans and human cells have uncovered similar patterns. In data from more than 480,000 people in the UK Biobank, a large repository of health information, those exposed to higher PM2.5 were more likely to develop glaucoma over time. In another study, scientists exposed lab-grown human retinal tissue made from stem cells to PM2.5. The particles disrupted retinal cell development, including that of retinal ganglion cells, while increasing cell death.

These studies offer pieces of a possible mechanism, but for now, how those pieces fit together in people remains unclear.

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

When millions of people died in Europe during the Black Death, biodiversity suffered too, new research suggests. The findings suggest that human activities once promoted biodiversity in the landscape — and experts say we could use these findings to boost biodiversity in our modern agricultural landscapes.

The 14th century was a tumultuous time for the people of Europe. Persistent cold, wet weather at the beginning of the century led to widespread agricultural failures and unprecedented levels of starvation in what became known as the Great Famine from 1315 to 1317.

This was followed by the Black Death, an epidemic of bubonic plague caused by the bacterium Yersinia pestis that killed more than a third of Europe's population. As a result of the widespread deaths and resultant social upheaval, large swaths of agricultural land were abandoned. Population levels didn't begin to recover until the 16th century.

The Black Death era is the perfect opportunity to look at the effects of humans on biodiversity over a longer period, Jonathan Gordon, a paleoecologist at the Leverhulme Centre for Anthropocene Biodiversity at the University of York and first author of the paper, told Live Science.

In the study, which was published March 4 in the journal Ecology Letters, the researchers compared more than 100 European pollen records that included about 4,600 samples. The records came from sites ranging from the lowlands of France and uplands of the southwest United Kingdom to the Swiss Alps.

The pollen records "give us information on the past diversity of the plant records," Gordon said.

For example, cereal grains ‪—‬ such as wheat, barley and rye ‪—‬ were a fundamental part of medieval agriculture. The representation of pollen from these types of crops in the pollen record points to historic land use.

The researchers divided the pollen data into three categories based on the presence of cereal pollen: places where agricultural production went up, places where it went down, and places where there was no evidence of cereal cultivation.

"We found a decline in biodiversity overall, but the decline overall was driven by those landscapes that declined in agricultural production," Gordon said.

"In those landscapes where agricultural production went down, there was a reduction in biodiversity of around 40%. Then, after about 150 years, as populations started recovering and landscape disturbances started increasing again, biodiversity went up to slightly above the level it was before."

Mosaic landscapes

Many people think there was a "stable and pristine world in which the entry of people has only one result: net loss of species and homogenization," Erle Ellis, an agroecologist at the University of Maryland, Baltimore County who was not involved in the research, told Live Science in an email. "The paleoecologists have always known the story is far more complicated."

There is a growing body of evidence showing that people's long-term cultural shaping of their landscapes often creates more diverse habitats, known as "mosaics," that can sustain more species than simple homogenous landscapes can, he said.

Whereas modern agriculture focuses on single crops on plots of land, in previous centuries, "you had all these different types of agriculture operating within the same landscape," Gordon said.

"In that landscape, you had lots of natural features that remained from the Middle or Early Holocene (which began after the last Ice Age about 12,000 years ago)," he added. "You had old bits of woodland, you had heaths, you had ponds, and bits of secondary forest. It was all interlaced with these agricultural mosaics, and that led to raised biodiversity because there were more habitats for different plant species to exploit."

The findings highlight the differences between medieval and modern land use practices — and their consequences for biodiversity. Research suggests that during the 20th century, global biodiversity declined by up to as much as 11% and human activities‬, such as land-use changes, pollution, and climate change‬, are the major culprits. In agriculture, the practice of monoculture — where a single crop species is grown over a large area — reduces biodiversity.

"What this work contributes to showing is that, until relatively recently, even in Europe, very different forms of land management and interaction were practiced than exist today," Patrick Roberts, director of Department of Coevolution of Land Use and Urbanisation at the Max Planck Institute of Geoanthropology, told Live Science in an email.

"Rather than the monoculture, plantations, or uniform changes to landscapes we see in the 20th and 21st centuries, emphasis was placed on maintaining 'mosaics,'" said Roberts, who was not involved in the new research.

In the study, "we can see how relationships between people and biodiversity have changed through time and how people can actively use landscapes while maintaining biodiversity and mixed ecosystem functions," he said.

There is still more to understand about how humans' disappearance from landscapes in the Black Death era affected the natural world, Gordon said. "There are a lot of other types of diversity ‪—‬ not just the number of types, but what the different types present actually do." There may be a hundred types of plants in a landscape, but if they do the same thing, "you have low functional diversity," he said.

Functional diversity "is super important for how ecosystems adapt to changes in climate and how resilient they are, which is something we need for future-proofing our agricultural system," Gordon said.

A mysterious "guest star" recorded by medieval astronomers nearly 850 years ago has revealed new secrets after scientists obtained the clearest images yet of its explosive aftermath.

New observations of Pa 30, thought to be the leftovers of a historic supernova called SN 1181, show that its spectacular firework-like filaments are not smooth streams of material. Instead, they consist of chains of tiny gas knots.

SN 1181 is so called because astronomers in China and Japan recorded its brief appearance in the year 1181, when they saw it as a naked-eye object in the constellation Cassiopeia. Eight surviving texts date its appearance to between Aug. 4 and 6 of that year. The mysterious object remained visible for 185 days.

"It's rare to get this level of detail on a supernova we can date to a specific week in history," Timothy Cunningham, an assistant professor of astronomy and astrophysics at the University of Warwick who led an international team of researchers to study the object, said in a statement.

SN 1181 is one of only five supernovas in the Milky Way galaxy known to have been witnessed from Earth before the invention of the telescope. (Those optical instruments first appeared in the Netherlands in 1608.) Now, advanced ground-based telescopes can produce wonderfully detailed images of those historic remnants. This latest image is from the Gemini North telescope on Mauna Kea in Hawaii and reveals about 10 times more filamentary structures in Pa 30 than have been seen before. This extraordinary detail gives astronomers fresh clues about the unusual explosion and the environment surrounding the star.

"These images give us the clearest picture yet of Pa 30's structure, and it's not what we expected," said Cunningham, whose team published their findings in The Astrophysical Journal. "The filaments are made of chains of tiny knots rather than smooth streaks, providing new constraints on the nature of the space around the star before it exploded and the physical processes that have shaped the expanding ejecta."

The knot-like structures may have resulted from variations in temperature or density in material surrounding the star as debris from the explosion expanded.

Pa 30 contains another unusual feature: a surviving star that sits almost exactly at the center of the remnant. That's highly unusual, because a supernova explosion typically sends stars away from their original positions. It suggests that the original explosion was highly symmetrical, the researchers said.

Furthermore, Pa 30 is thought to be a Type Iax supernova. Unlike standard Type Ia supernovas, which destroy their stars, a Type Iax event is a lower-energy, incomplete explosion of a white dwarf star that can leave behind a remnant known as a "zombie star." It's the only Type Iax supernova ever found.

Like their cephalopod cousins the octopuses, cuttlefish are masters of disguise.

As they hunt, these marine predators send waves of color across their skin. The rainbow display stops prey in their tracks, granting the cuttlefish just enough time to shoot out two specialized hunting tentacles at lightning speed and snatch them into range of their deadly beaks.

But can cuttlefish actually mesmerize prey with their colorful skin changes? Or is something fishier at play?

Experts told Live Science that cuttlefish are ingenious hunters, but that there's likely an even more mysterious process than hunter to prey hypnosis going down on the seafloor.

A calculated hunter

Cuttlefish are visual hunters, using their large, complex eyes to locate and track potential meals. In general, their strategy involves a slow, stealthy approach, said Bret Grasse, the manager of cephalopod operations at the Marine Biological Laboratory in Woods Hole Massachusetts.

"The cuttlefish will slowly approach the prey so as to not alert the unsuspecting shrimp, fish or crab," Grasse told Live Science in an email.

During their approach, cuttlefish often put on a showy display, producing moving bands across their body. These displays are produced by a combination of light-reflecting pigment cells known as iridophores, leucophores and chromatophores. These cell types contract and expand to produce specific colors and patterns, all within milliseconds.

Some may wonder whether this trick can mesmerize prey, but scientists don't think that's the case.

Hypnosis, defined as a mental state of increased relaxation and altered awareness, is thought to be a uniquely human psychological state. There is very little research on whether fish can be hypnotized, but a 2005 study found that pushing a steady stream of water through the snapper (Chrysophrys auratus) put them in an immobile state similar to being hypnotized. Another study looked at sedative hypnotic drugs like benzodiazepines and barbiturates and their effects on zebrafish, finding that the fish had molecular receptors for these drugs, which helped render them immobile. However, whether fish can be visually put into a state like hypnosis has yet to be directly studied.

And while some animals, such as chickens, can be induced into trance-like conditions of tonic immobility, an involuntary, temporary state of unresponsiveness that happens when humans or animals experience extreme trauma, it's unlikely that the cuttlefish's color changes "hypnotize" their prey, Connor Gibbons, the cephalopod facility manager at Columbia University told Live Science. Instead, some researchers believe that the color show serves as an ingenious disguise.

As waves of different colors ripple down the cuttlefish's body, the shape of the animal becomes less obvious to its prey, so they may not see the cuttlefish as a threat to flee from, Gibbons said.

"It's only part of something looming at them, which they're like, 'I don't know if you are a predator? Are you just passing waves? What are you?'" Gibbons said. "And then by that time, it's too late."

Once they get close enough, the cuttlefish shoots their two long, specialized feeding tentacles from small hidden pouches near the animal's mouth at their prey.

"The closest thing I can compare it to is the tongue of a chameleon extending out to grab an unsuspecting insect," Grasse said. "Cuttlefish feeding tentacles will fire out in the blink of an eye before the prey can react and escape."

Then, the prey is pulled toward the cuttlefish's mouth, pierced by its sharp, chitinous beak and injected with venom. The use of the venom helps the cuttlefish reduce their energy usage when hunting "as the cuttlefish does not want to use unnecessary energy and struggle against the prey while it's trying to eat," Grasse said.

However, the notion that cuttlefish flash colors to hide their body shape is only one idea of why cuttlefish perform these strobing color displays. Other researchers, including Grasse, describe them as a way to distract their prey.

"Essentially, they are trying their best not to alarm the prey to their presence," he said. By breaking up the size of their bodies, cuttlefish can convince their prey they're not as large or alarming as they may seem.

Whether the light shows are for disguise or distraction still needs parsing out, Gibbons said, and scientists also need a better understanding of how the cuttlefish controls its deadly dermal display. "The jury is still out on exactly what is happening," he said.

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When temperatures spike, California redwoods slow down photosynthesis, new research has found. This finding has serious implications for the long-term survival of the iconic trees in a warming world, and their role in storing carbon from the atmosphere.

California redwood (Sequoia sempervirens) forests are among the largest aboveground carbon stores on the planet. These towering trees are native to central and northern California, and evolved to take advantage of the region's historically mild weather. In recent decades, their range has contracted significantly. But climate change is threatening the health and function of these forests.

The region has seen significant warming in recent decades, and faces more frequent extreme heat days, with temperatures spiking above 100 degrees Fahrenheit (37 degrees Celsius). Now, in a new study, published Sept. 22 in the journal JGR Biogeosciences, a team of researchers has shown that California's renowned redwoods are struggling to photosynthesize in the heat.

Photosynthesis is the process used by plants, algae and some bacteria to turn sunlight into energy. It chemically converts carbon dioxide and water into sugars and oxygen.

"These trees adapted to grow in really temperate environments, so no one had really looked at the impact of heat on photosynthesis," study first author Lily Klinek, a doctoral candidate in the Plant Optics Lab at the University of California, Davis, told Live Science.

From 2022 to 2024, Klinek and colleagues measured how the leaves of redwoods in Garcia River Forest in Mendocino County responded to the heat. Once or twice a month, the researchers took three different California redwood leaf samples and measured their fluorescence and temperature.

A plant's molecules can use absorbed light in three ways: for photosynthesis, dissipated as heat, or reflected as light (florescence). Fluorescence is a proxy measurement to understand photosynthesis in the plant, Klinek said.

The researchers wrapped a fourth leaf in tinfoil for 20 minutes to put it in a state of "rest" before taking the same measurements. "When they're in a state of rest, we expose them to a pulse of light that’s in the wavelength they would use for photosynthesis to see what would be their maximum photosynthetic rate," Klinek said.

They found that on hot days, the leaves exposed to sunlight were up to 18 degrees Fahrenheit (10 degrees Celsius) hotter than the air temperature. "That's a huge difference and indicates that the leaves are stressed to the point where they can't thermoregulate effectively," Klinek said.

Many plants' leaves manage their temperature and photosynthesis by opening or closing their stomata, which are tiny pores on their surface. These stomata (from the Greek word for mouth) regulate the amount of carbon dioxide entering the plant, and how much oxygen and water vapor it releases. Lower carbon dioxide intake leads to reduced photosynthesis, meaning the plant has less energy.

The large differences between air and redwood leaf temperatures suggest that the leaves had closed their stomata to avoid losing water from evaporation during hot conditions and consequently overheated, Klinek said.

To further investigate the impact of heat on leaf physiology, the researchers took California redwood leaf samples back to the laboratory and exposed them to a range of temperatures while they were in water. Despite their access to water, the leaves still photosynthesized less as they got hotter, even though their stomata were open, Klinek said.

This shows that heat imposes direct limitations on redwood photosynthetical capacity, rather than indirectly decreasing that capacity by causing stomatal closure, the researchers wrote. The finding indicates that redwoods' ability to photosynthesise and store carbon will decrease as temperatures rise.

​​"It is not only stomatal closure that is causing reduced photosynthesis," Lucy Rowland, an ecologist at the University of Exeter in the U.K. who was not involved in the study, told Live Science in an email. "These trees are already suffering from the direct effects of heat on their photosynthetic systems."

The finding has serious implications for the future of redwoods and similar plants. "The points at which this damage becomes irreversible remains really poorly understood, but is something which is really essential to understand if we want to predict how our future climate is going to impact plants," she said.

The next step in Klinek's research is to move beyond leaf physiology to understand these thresholds on the trees and their ecosystems as a whole.

"We're not sure to what extent the effect that we saw is a reversible stress response and if they are sustaining damage from this constant stress," she said. Researchers need more data to "really get a better sense, beyond the leaf scale, how these ecosystems are responding to heat and drought," she added.

Recent research challenges a long-standing idea about how the brain develops: Rather than arising from a single source, the brain may emerge from two distinct populations of cells, the study finds.

"The brain appears as one organ," said study co-author Kyle Loh, an associate professor of developmental biology at Stanford University. "However, we discovered that the front part of the brain and the back part of the brain come from different sources, which are pushed together to create the appearance of a single organ," Loh told Live Science in an email.

The findings, published in September in the journal Nature Neuroscience, not only challenge established models of how the brain forms but may also explain why researchers have struggled to grow certain types of brain cells in the laboratory. The scientists say the work could offer new ways to investigate diseases that affect the brainstem, the "stalk" that connects the brain to the spinal cord.

Two developmental journeys

The human brain is divided into three main regions — called the forebrain, midbrain and hindbrain — that perform different but interconnected functions.

The forebrain, which includes the cerebral hemispheres, is involved in higher-level cognitive processes, such as language, planning and abstract thinking. The midbrain, the uppermost part of the brainstem, connects the forebrain and the hindbrain and acts as a key relay center for sensory information and movement control. The hindbrain — which includes the bottom of the brainstem, along with other structures — also helps to coordinate movement, as well as regulate essential functions such as breathing, sleep and heart rate.

Historically, the hindbrain has been difficult to study. One reason is that scientists have faced persistent challenges in generating functional hindbrain neurons in laboratory conditions.

To help understand why, Loh and his team looked at the early stages of embryonic development in lab mice. They focused on gastrulation, the point when cells begin to organize into structures that will later form different organs. The researchers identified two distinct populations of immature cells that would go on to give rise to nervous system tissue, including the brain.

One cell population expressed a gene called Otx2, which helps to direct the early development of the forebrain and midbrain. The second group of cells expressed the gene Gbx2, which is involved in the development of the midbrain and hindbrain.

The functions of these genes were already known, but their distinct expression in these two groups of cells was revealed by the new research. The cell populations remained distinct as they developed into full-fledged nervous tissue, rather than overlapping.

The team also examined chromatin, the molecular structure that packages DNA tightly inside the nucleus and helps regulate which genes a cell can use. The two cell populations show different chromatin configurations, the team found, which further supports the idea that they follow separate developmental pathways.

That may help to explain why scientists' attempts to grow hindbrain neurons have been largely unsuccessful.

"Previous attempts to make hindbrain neurons likely tried to coax forebrain and midbrain progenitors into hindbrain cells, which our study shows is not possible," study co-author Rayyan Jokhai, a graduate student in Loh's lab, said in a statement.

Why it matters

Using the information uncovered in their experiments, the researchers successfully guided human stem cells to transform into functional hindbrain motor neurons, which are involved in controlling movement. Specifically, these cells produced proteins characteristic of the hard-to-grow hindbrain regions that help control muscles of the face and those involved in swallowing.

In several neurological diseases, including spinal muscular atrophy and amyotrophic lateral sclerosis, motor neurons deteriorate and affected patients can lose their ability to swallow, speak and breathe independently.

"We cannot sample living motor neurons from a patient's hindbrain to watch how these diseases attack these neurons," Loh said. "Growing these hindbrain motor neurons in a dish gives us a way to investigate these diseases." Looking forward, the team aims to use their findings to study these diseases and pinpoint new treatments.

The new findings could also reveal something fundamental about the evolution of vertebrate animals.

The study authors investigated whether the two developmental pathways were unique to humans or reflected a much older evolutionary arrangement. They turned to previously published data on other species — including macaques (Macaca), zebrafish (Danio rerio) and chickens (Gallus gallus domesticus) — and again found two distinct cell populations expressing the two key genes.

And even in acorn worms — a marine invertebrate whose evolution diverged from vertebrates about 550 million years ago — they again found these two distinct groups of cells.

"The Stanford discovery establishes that the deep ancestry of the vertebrate brain is fundamentally modular," said Anna Di Cosmo, a professor of biology at the University of Naples Federico II in Italy who wasn't involved with the study. "The developmental separation between the anterior lineage (forebrain/midbrain) and the posterior lineage (hindbrain) is traceably ancient," Cosmo told Live Science in an email.

Loh's team speculates that these developmental trajectories seen in the womb may suggest that the two cell populations once belonged to two separate nervous systems. "Later in evolution, these two nervous systems may have been pushed together to give rise to the appearance of one integrated brain," Loh said.

However, the study doesn't reveal exactly when the two pathways arose or establish how they integrated. "It is important to emphasize that this is only an idea, and it might change as scientists learn more," Loh said.

See how much you know about the most complex organ in the human body with our brain quiz!

A new 4,300-mile (7,000-kilometer) undersea fiber cable will shuttle data between the U.S. and France at breakneck speeds of up to 1 million gigabits per second (Gbps) — enough to move around 125 terabytes of data every second, or roughly 25,000 HD movies, each 5 gigabytes large. The cable, called Petal, will be funded and operated by Facebook and Instagram parent company Meta.

When it comes online in 2029, the ocean-spanning cable will be the first to deliver petabit capacity — double the capacity of existing subsea cables of this length — across transoceanic distances, Meta representatives said in a statement. That's enough to allow 75% of the world's population to stream music at once.

Petal will also be the first commercial subsea cable system to use multi-core fiber technology, according to the statement. Whereas conventional fiber strands typically contain a single core, each of Petal's fiber strands will contain two cores that carry optical signals in opposite directions, allowing a single strand to provide the capacity that would conventionally require a pair of single-core fibers.

Each fiber strand is roughly as thick as a human hair, measuring just 125 micrometers in diameter. Petal will contain 24 pairs of dual-core fibers, giving it 96 individual fiber cores in total and enabling it to carry as much data as 48 conventional fiber pairs, Meta engineers said.

Japanese technology company NEC will be responsible for the overall design and construction of Petal, while Sumitomo Electric will provide the fiber itself.

"Achieving petabit-per-second capacity across a transoceanic submarine system represents a major technological milestone in the history of global telecommunications," Eduardo Mateo, chief strategy officer of the Submarine Networks Division at NEC, said in the statement.

Bedrock of the internet

Subsea cables are among the most critical layers of internet infrastructure, carrying around 99% of the world's internet traffic, according to the International Telecommunication Union, the United Nations ​agency for digital technologies.

Installing thousands of miles of fragile glass cable on the ocean floor is an engineering feat in itself. Equally challenging is ensuring that these cables can carry the tiny pulses of infrared light that transport fiber-optic data across such huge distances without impacting performance.

This is typically achieved through repeaters — amplifiers installed at regular intervals along the cable that use lasers to boost the optical signals.

A 4,300-mile subsea cable typically needs about 100 of these repeaters to amplify the signals along its length, Meta representatives said.

Petal will incorporate something called "fan-in/fan-out" technology. As each two-core fiber strand enters a repeater, an optical interface routes the signal from each core into a separate single-core fiber strand so that each can be amplified independently. The amplified signals are then routed back into the two cores of the dual-core fiber before continuing along the cable.

Combined with its dual-core fiber, this feat of signal engineering will enable Petal to double its data-carrying capacity without requiring a proportional increase in power, Meta representatives said.

Petal is one of many subsea cable investments by Meta in recent years, including Marea in 2018, Amitie in 2023 and Anjana in 2025. Marea, the company's first transatlantic fiber instalment, supports 192 Tbps, meaning Petal will offer more than five times that capacity.

Sometimes, it takes a great struggle to build towering peaks. And what more thunderous event is there than the clashing of continental plates?

Geological pileups have birthed some of the largest and tallest mountains on the planet, including Mount Everest and its Himalayan neighbors. But has there ever been a peak taller than Mount Everest, which stands 29,032 feet (8,849 meters) above sea level?

The answer is still a mystery, but there are some geological clues about where the tallest peaks would have been in the ancient past, experts told Live Science.

Earth's lost mountains

Geologists don't have the level of detail required to pinpoint an exact highest peak hundreds of millions of years ago. "We're never going to get that granularity, unfortunately," Alan Collins, a professor of geology at Adelaide University in Australia, told Live Science.

However, clues in residual sediments lodged inside Earth's crust hint at the lost grandeur of primordial snowcaps and summits. Scientists study these crusts to understand how deep they went, which can reveal how tall ancient mountains might have been.

Mountains are really just parts of the continental crust that have been thrust upward as tectonic plates slowly crash together. This crust is very heavy, and there is much more to it than what you see on the surface; even the most spectacularly tall peaks, like Everest, are anchored in deep crust. Just as crust gets thrust up to form mountain peaks, it also gets pushed deep under the surface. Both Collins and Ziyi Zhu, a geochemist at Curtin University in Australia, compared mountains to icebergs, in the sense that only a bit pokes above the surface.

"We can argue or speculate that [the biggest mountain] was in a place where there were deep roots in the crust," Zhu told Live Science.

Geologists estimate that the Himalayas, for example, have a crustal column that goes down as far as 50 miles (80 kilometers). Compare that to Everest's elevation of about 29,000 feet (9,000 m), and the world's tallest mountain at most represents only 14% of the rock slab it's part of. That means there's a limit to how tall mountains can get before they collapse under their own weight.

The Himalayas began forming between 50 million and 40 million years ago from the collision between the Indian Eurasian continental plates. As far as mountains go, they are relatively young. And that's partly why they are still so tall. Tall, jagged mountains erode quickly over time, though the Himalayas are still growing as the two plates continue to collide.

Such continental collisions have happened countless times before, though. For example, the Transgondwanan Supermountain, an ancient range in what is now East Africa, began emerging some 650 million years ago when Africa and South America crashed into Arabia, India, Australia and Antarctica to form the supercontinent Gondwana.

Gondwana split up again, but evidence of these mountains in places like southern India, Sri Lanka, Tanzania and Kenya point to them being three times the length of the Himalayas. "If you walk around there now, you can see rocks that were at the bottom of this mountain belt," Collins told Live Science. On average, the crust is deeper than the crust of the Himalayas. "We think this is at least the scale of the Himalayas if not more," Collins said.

The crusts found in these areas also hint at how tall the mountains were, with sections that descend up to 18 miles (30 km) deep, despite half a billion years of erosion. "At some point, they were likely halfway down a crustal column that was 60 kilometers [37 miles deep]," Collins said. This means that the mountains above this base could have been as tall as Everest.

In the Himalayas, the tallest mountains sit around the rim of the Tibetan Plateau, which has the highest elevation on the planet, at about 3.7 miles (6 km) above sea level, on average. The Transgondwanan range may have had a similar plateau around southern Madagascar, meaning its rim would have been in eastern Madagascar, southern India and eastern Antarctica, Collins said.

Another candidate for the tallest mountains was the Grenville orogeny, which popped up with the formation of the supercontinent Rodinia starting about 1.3 billion years ago. Its remains can be seen around southeastern Ontario and northwestern Vermont. But less is known about this extinct range, Collins said, with some scholars arguing that it wouldn't have been as tall as the Transgondwanan range or the Himalayas.

Further back, some 2 billion years ago, the formation of the supercontinent Nuna (also called Columbia) also left evidence of truly giant mountains. Zhu's paper found evidence of this supermountain by examining the composition of zircon crystals left in the crust underneath this vanished range.

Look any further back, however, and the picture gets murkier. When Earth was hotter, mountains likely couldn't get as high because warmer crusts can support less weight, Collins said. Stable continental plates and rocks didn't start to form until about 4 billion years ago, and it took hundreds of millions of additional years for large continents to form.

For Zhu, the Nuna, Transgondwana and Himalaya ranges are currently the best candidates for holding the tallest mountains that ever existed. But it's likely impossible to pinpoint the highest specific peak, at least with current scientific methods. "It's an open question," Zhu said.

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

Archaeologists digging at a 13,800-year-old site in interior Alaska have unearthed thousands of artifacts and fossils, including what may be the bones of the earliest domesticated dogs in the Americas, the earliest needles and dwellings in the Western Hemisphere, and stone tools that reveal cultural connections across the Bering Land Bridge.

At a site called Shégˊ Xdaltthˊíˊ (which means "They Were There" in the Alaska Native Athabascan language), about 34 miles (55 kilometers) southeast of Fairbanks, archaeologists have excavated an encampment that some of the first people to settle in North America used off and on for a millennium.

Shégˊ Xdaltthˊíˊ is located in eastern Beringia, the geographical region that connected northeast Asia and northwest North America during the last ice age. The most recent archaeological and genetic studies suggest that the ancestors of today's Indigenous Americans entered the continent around 21,000 years ago. But since Beringian sites are often the remains of small seasonal hunting camps and are scattered across a large geographic area, much is still unknown about the earliest people who called the Western Hemisphere home.

"I expected we'd find hunting tools and knapping [stone tool making] debris surrounding a hearth or two, but I had no idea that we'd stumble into a base camp with tens of thousands of artifacts," study first author Kelly Graf, an archaeologist at the University of Kansas, told Live Science in an email. "It was a total surprise!"

In a study published Wednesday (Oct. 14) in the journal Science Advances, Graf and co-authors detailed their discoveries at Shégˊ Xdaltthˊíˊ, focusing on the earliest occupation, which occurred around 13,800 years ago, as evidence of people "settling in" to their new territory.

The researchers found a hearth, a small pit, and a dirt stain where a wooden post had once stood, likely the remains of a lean-to or early tent house. Additionally, the archaeologists unearthed stone tools, bone needles and a pendant made from an antler. Nearby, they found an earth oven, which was full of charcoal and animal bones and was likely used to slow-cook meat for a large family group.

"The complex feature at Shégˊ Xdaltthˊíˊ represents the earliest potential case of a habitation structure in North America," the researchers wrote in the study. "Early Alaskans knew their surroundings well."

Cross-cultural links

The archaeologists were also surprised by the stone tools recovered at Shégˊ Xdaltthˊíˊ because they are distinctively shaped and unique to central Alaska. Known as diamond-shaped hafted bifaces, the tools were crafted from rhyolite and basalt and are similar to those typically found much farther west in Beringia, in modern-day northern Siberia. Additionally, obsidian artifacts discovered at Shégˊ Xdaltthˊíˊ reveal that people brought the volcanic rock to the site from a geological source hundreds of miles to the northwest.

Bones from more than a dozen wolf-like animals suggest a further connection to Asia, according to the researchers. An analysis of the jaw of one of the animals showed that it was not from a dire wolf (Aenocyon dirus) or from a Pleistocene Beringian or gray wolf (Canis lupus sp.) but rather a population of wolf-like animals unique to central Alaska. Current genetic evidence suggests that early domesticated dogs in North America came from Siberian wolves. The timing and geographical location of Shégˊ Xdaltthˊíˊ provides circumstantial evidence that the people may have been dog owners.

"Like humans, potentially, the canids of Shégˊ Xdaltthˊíˊ and other early Alaskan sites were recent immigrants from Asian Beringia," the researchers wrote.

Although Shégˊ Xdaltthˊíˊ reveals a relationship with sites in Asia, there is also evidence of connections with early American sites south of the Canadian ice sheets, according to the study.

One clue to these connections is the presence of bone artifacts in a sewing kit. The archaeologists found eight bone needle fragments at Shégˊ Xdaltthˊíˊ. Previously, the only recovered eyed needles had come from Paleoindian sites in temperate North America. Therefore, the needles from Shégˊ Xdaltthˊíˊ are the oldest needles ever discovered in the Western Hemisphere, and they reveal connections with sites farther south, according to the study.

Another clue is the pendant, which was crafted from antler. The pendant had a hole drilled at one end and was fashioned into a point at the other end. This piece of ancient jewelry is similar to personal adornment items found farther south in North America.

"The co-occurrence of these cultural features at the single site of Shégˊ Xdaltthˊíˊ is truly notable," the researchers wrote, and they "highlight the strong cultural connection between early Beringians and Americans."

It is still unclear whether the people at Shégˊ Xdaltthˊíˊ were traveling to make these connections. "It would be hard to pin down whether or not they were moving back and forth during a lifetime, but at least we can say there is a connection," Graf said.

Further work in Beringia is needed

Future excavations in Beringia could help archaeologists learn more about the earliest people in the Americas, according to Graf. "Alaska is a big place and so remote, so there are really just a few small areas that have been intensively investigated," she said.

Spencer Pelton, an archaeologist at the University of Wyoming who was not involved in the research, wrote in an accompanying perspective published in the journal Science Advances that early Indigenous sites in Beringia are key to understanding the peopling of the Americas.

"Shégˊ Xdaltthˊíˊ is remarkable because it is the oldest site in the Americas containing a large and rich assemblage of features, artifacts, and faunal refuse indicative of prolonged residential occupation, providing an unprecedented glimpse into the lives of North America's first residents," Pelton wrote.

Graf is already planning future archaeological excavations in the area. "We're hoping to bring some younger Alaska Native folks out with us in the coming summers," she said, as incorporating local knowledge is important to the project. "Two of our co-authors are elders from Alaska Native corporations nearest to the site," she said. Elders named the Shégˊ Xdaltthˊíˊ site and have visited it to discuss where to excavate and what the archaeologists might find.

There is much left to learn about what was happening in Beringia 14,000 years ago, the researchers wrote, particularly since there are currently only two archaeological sites — including the 24,000-year-old Bluefish Caves site in the Yukon — that suggest humans were settling in Beringia considerably earlier.

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

"Necklaces" of ultracold atoms have provided new evidence to support a nearly 100-year-old quantum theory.

In 1931, physicists were trying to use quantum mechanics to explain why some materials are magnetic. Then, a young physicist named Hans Bethe looked at a single row of electrons. Each electron's spin can point up or down. Bethe worked out the math for how such a row behaves and found that if a few spins in the row flip, they can stick together and travel down the row as a single unit.

Decades later, physicists found that Bethe's method also works for larger particles moving along a line, such as atoms. If those particles attract each other, the math predicts they will bind into clusters called Bethe strings.

Now, physicists have found evidence of these clusters in a line of ultracold atoms. The findings were published Aug. 29 in the journal Nature Communications.

The discovery may not create new gadgets, but it addresses a fundamental mystery in physics. Everything around us, from magnets to phone chips, consists of countless interacting particles. This makes their behavior difficult to predict. Ultracold atoms serve as a clear and adjustable way to study these complex systems.

A "necklace" of atoms

Researchers have spotted small Bethe strings before, in magnetic crystals and superconducting quantum circuits ‪— but those experiments captured strings one at a time.

Theory predicts that crowds of strings, in many sizes, can change how an entire system behaves, and studying that idea requires making many strings at once. That has been hard to do with atoms. Atoms that attract each other usually collapse into a clump. But this time, the team appears to have made many strings of different sizes at once, including some with more than six atoms.

It's tricky to get atoms to attract each other. In three dimensions, a gas made of attracting atoms tends to collapse as the atoms clump together and form molecules. That process releases energy that kicks atoms out of the experiment, so the gas quickly collapses and disappears. But when they're in a single line, the atoms behave differently.

"They are really a bit like pearls on a string, right? Like on a necklace, they cannot go past," study co-author Hanns-Christoph Nägerl, an experimental physicist at the University of Innsbruck, told Live Science. "In 3D, everything would collapse. But in 1D, it does not collapse."

To build their "necklaces," the team started with tens of thousands of cesium atoms cooled into a Bose-Einstein condensate ‪— a state of matter in which atoms chilled to near absolute zero share a single quantum state. Laser beams then divided the condensate into thousands of thin tubes, each of which held up to a few dozen atoms in a line.

At first, the atoms repelled each other. The researchers used a magnetic field to gradually turn that repulsion down to zero, and then turned it into attraction.

The team couldn't see the strings directly. Instead, they let the atoms go and measured how fast the cloud spread. When the atoms could expand only along their tubes, any strings stayed intact. When the atoms were freed in all three dimensions, the strings broke apart and released their binding energy as motion. The researchers found that the 3D clouds spread with about three times as much energy as the one-dimensional ones did.

From that difference, the team estimated how tightly the atoms had been bound. The answer pointed to strings of at least six atoms. The measurements also closely matched predictions from a theory called generalized hydrodynamics, which describes a gas like this one as a fluid made of many kinds of particles, including strings of different sizes. It also tracks how each kind flows over time rather than following every atom.

Nägerl was careful not to call this proof. "That some theory fits to your data is not a proof that something exists," he said; it's just more evidence to support it.

A short-lived state

The strings likely don't survive long. Up close, the atoms still feel the three-dimensional world, and the strings eventually decay into ordinary cesium molecules. In the coldest runs, the team lost about 40% of the atoms.

"Transiently you create these Bethe string states," Nägerl said. "But I don't think they are long-lived."

He has an idea for future experiments. Physicists recently learned to shield ultracold molecules with microwaves, which keeps the molecules from colliding at close range. Strings made from shielded molecules might last long enough to be studied directly. But Nägerl stressed that the idea is untested. "I've had nobody do a theory check on my claims now, but I think intuitively this should work," he said.

Another option is quantum gas microscopy, which images atoms one at a time and could offer more direct evidence of individual strings.

For Nägerl, Bethe strings are one step in understanding how quantum systems with many particles behave and settle down over time. His long-term goal is an experiment in which physicists control both how every particle moves and how its spin flips, letting them assemble model materials piece by piece, "like a LEGO type," he said. His team has begun the next step: using lasers to control the spins of the atoms in its one-dimensional gas. He described Bethe strings as "a little diversion." But because the strings form whenever the atoms attract, they can't be ignored.

A fossil that sat in a museum collection for over a century is a previously unknown species of predatory dinosaur, researchers have found. The discovery could help scientists solve a longstanding mystery about how some of the Cretaceous period's most formidable hunters spread around the globe.

The dinosaur lived on what is now the Isle of Wight in southern England about 120 million years ago. It belonged to a group of two-legged carnivores called megaraptors, which are related to tyrannosaurs. But unlike tyrannousars, megaraptors are thought to have relied on their powerful arms and large curved claws to attack prey and defend themselves.

The newly identified species was described in an Oct. 14 study in the journal Royal Society Open Science. It is the first megaraptor identified in Europe, filling an important gap in the fossil record of a group whose evolutionary history remains poorly understood.

"It is a real mystery that this fossil was overlooked for so long, sitting in a drawer for nearly 100 years," study first author Cassius Morrison, a researcher in the Department of Earth Sciences at University College London (UCL) said in a statement. "Lots of bones are found on the Isle of Wight — who knows what else is waiting to be discovered."

Unconquered female warrior dinosaur

The discovery of the megaraptor began in 1924, when an amateur fossil collector discovered a dinosaur skull fragment on the Isle of Wight. The specimen eventually entered the collections of London's Natural History Museum, but it was largely forgotten.

Recently, researchers revisited the fossil as part of a study on dinosaur braincases. To identify the animal, the researchers used micro-CT scanning to examine the fossil's internal structure and build detailed 3D digital models of the space that once held the dinosaur's brain.

The researchers then compared the animal's anatomy with that of other meat-eating dinosaurs, including tyrannosaurs, spinosaurs and other theropods (the group of two-legged, mostly meat-eating dinosaurs). Several features differentiated the unknown specimen, including an almost oval opening where the spinal cord entered the skull and an unusual, hourglass-shaped ridge at the back of the braincase.

Computer-based evolutionary analyses placed the fossils within the Megaraptora family tree, supporting the idea that the skull represented a never-before-seen species. The researchers named the dinosaur Invictibellatrix amberina, combining the Latin words "unconquered" and "female warrior" for the genus name, while amberina refers to amber found in the rocks associated with the fossil.

Megaraptors lived between roughly 125 million and 66 million years ago and varied considerably in size. While early members were relatively small, some later species became enormous predators. Maip macrothorax, discovered in Argentina, may have reached up to 33 feet (10 meters) long and weighed as much as an elephant. Based on comparisons with related dinosaurs, I. amberina was much smaller, likely around 10 to 13 feet (3 to 4 m) long and standing roughly 5 feet (1.5 m) tall. The researchers estimated it weighed around 440 to 660 pounds (200 to 300 kilograms), making it one of the smallest known megaraptors.

"It was not the apex predator of its time, but for humans this dinosaur would have been more dangerous than a T. rex," Morrison said. "We would have been perfectly sized prey, about a third of their body weight. They definitely would have chased us."

Although the newly described fossil doesn't preserve the animal's arms or claws, its closest relative suggests that its claws may have measured around 4 to 8 inches (10 to 20 centimeters) long. The researchers also suggested I. amberina may have been feathered, though that feature can't be determined directly from the specimen.

A missing link in the dinosaurs' globetrotting

Scientists have long suspected that megaraptors originated in Asia before spreading to other parts of the world, eventually becoming the dominant predators across the southern supercontinent Gondwana, which included present-day Africa, South America and Antarctica. But a lack of European fossils left an important gap in verifying this migration route.

The new study's evolutionary models suggest that I. amberina descended from Asian megaraptors that dispersed into Europe around 130 million years ago. From there, members of the group may have moved through what is now Africa and further into Gondwana via temporary landbridges and temporary land connections across the shallow Tethys Ocean.

"This new species is the first proof we have that megaraptorans were also present in Europe and that they reached Gondwana this way rather than island-hopping further south," study co-author Charlie Scherer, a doctoral student at UCL Earth Sciences, said in the statement.

However, the specific route these animals took over millions of years is still unknown. The researchers also cannot yet explain why megaraptors disappeared from northern areas, but changes in climate or competition with other predatory dinosaurs may have contributed. More research on other megaraptor fossils like I. amberina could help uncover more clues.

"Work like this shows the exceptional value of working with historical museum collections where there are still many discoveries to be made," study co-author Paul Barrett, a researcher of dinosaur evolution at the Natural History Museum in London, said in the statement.

Stellar cores called white dwarfs come in an astonishing array of colors, including what scientists say is the first known green star and the reddest star ever found, new research reveals.

A white dwarf star is the dense, cooling core that remains after a low- to medium-mass star runs out of fuel. The new study, published Thursday (Oct. 15) in the journal RAS Techniques and Instruments, shows that white dwarfs come in far more colors than their name suggests.

White dwarf stars got their moniker because the first known examples glowed in either white or pale blue. The new study, however, suggests that "white" dwarfs also emit visible-light colors like pink, green, cyan, purple and yellow.

"Most stars, including most white dwarfs, behave like 'perfect radiators,' so their colour is set almost entirely by temperature. But nobody had really looked into what else might be possible for white dwarfs," Mark Hollands, an astronomer at the University of Warwick in the U.K. and first author of the study, said in a statement. "It turns out these incredibly dense stars can produce colours nobody expected, and some of them genuinely surprised me."

The variety of colors is possible due to white dwarfs' densities compared with main-sequence stars, the study suggests. Cooler white dwarfs have a density of about 1 gram per cubic centimeter, much like flowing water on Earth. The density of these white dwarfs is also millions of times denser than the sun's visible surface, or photosphere, leading to unusual conditions.

"Any trace elements that may be present, such as carbon, calcium and sodium, interact with the surrounding dense helium plasma and absorb light across a wider range of colours than they would at lower densities," the researchers said in a statement. "This shifts a star's colour away from the orange, white and blue [typical] of a perfect radiator."

White dwarfs are far away and small, making it difficult to verify their color. So, in the new study, astronomers inferred the colors using spectra, the distinctive chemical fingerprints produced by stars' light. The team analyzed the spectra within a model of color vision that the human eye can see, making the color pop out.

Scientists found that carbon-rich white dwarfs tend to be purple or pink, while those that contain debris from asteroids or comets are usually yellower. Cyan or pale-blue white dwarfs occur when hydrogen and helium molecules strike each other in very dense atmospheres.

The team also discovered WD J1330+6435 — a green star that contains rocky material. The green comes from the additional elements of calcium, lithium and sodium in the star's atmosphere, creating a unique "chartreuse green appearance" that would be visible to the human eye, if we could see it up close.

"The traces of sodium in the atmosphere of this white dwarf absorb the orange part of the spectrum, leaving behind a ghostly green glow," Hollands explained, adding that the one-of-a-kind green star "feels like something out of science fiction." The team also discovered what is likely the reddest star ever found. This white dwarf, called WD J1011+2845, is located roughly 48 light-years from our planet. It has carbon closer to its surface — because the element is being lifted from the interior, due to strong convection currents — that is bending the star's light. This process is making a "deep salmon-pink glow" because the carbon molecules are obstructing the star's other wavelengths.

Overall, in the sample of stars studied — 151 white dwarfs within 65 light-years of Earth — about 1 in 30 white dwarfs glowed in a color other than white. This could mean there are far more colorful stellar remnants littering the universe than anyone anticipated.

While working on his land in a village in northern Egypt, a man made an astonishing discovery: the remains of two massive statues of Ramesses II.

The man, Khaled el-Shahat, immediately notified the Egyptian Ministry of Tourism and Antiquities, which sent a team to the village of Behbeit El Hagar to excavate and study the statues, the ministry said in a translated statement.

Ramesses II had one of the longest reigns in Egypt's history, ruling from around 1279 to 1213 B.C. During his 66 years in power, Egypt controlled an empire that stretched as far northeast as modern-day Syria. He initiated many building projects throughout the empire, and numerous Ramesses II statues have been found throughout Egypt.

Archaeologists had previously found architectural fragments bearing the name of Ramesses II at Behbeit El Hagar, which is known for its temple dedicated to Isis, a goddess associated with healing and magic, said Mahmoud Emam, an Egyptologist at Cairo University who has worked on remains from the site but was not involved with the recent excavation. He noted that the newly found statues were unearthed on the western side of the temple complex.

"Strong Bull"

Both of the newfound statues were once larger than life, with the bigger one likely standing nearly 28 feet (8.5 meters) tall when it was originally built. However, most of what remains is its head, which is 5.2 feet (1.6 m) tall and depicts the pharaoh wearing the double crown of Upper and Lower Egypt.

Part of this large statue's back pillar has a hieroglyphic inscription that gives the pharaoh's "Horus" name: Hor-Ka-Nakht-Mery-Maat. This name means "Strong Bull, Beloved of Right, Truth," Joyce Tyldesley, a professor emeritus of Egyptology at the University of Manchester in the U.K., wrote in her book "Ramesses: Egypt's Greatest Pharaoh" (Penguin Books, 2001). In Egypt, it was common for pharaohs to have several alternate names with a Horus name, given in honor of the sky god Horus.

The second statue, which stands about 7.9 feet (2.4 m), also likely depicts Ramesses II, the statement said. The king is shown wearing the "Nemes" headdress, a type of striped headcloth that pharaohs wore, the Egypt Exploration Society notes on its website.

Near this statue is a block of pink granite with two hieroglyphic inscriptions that name Ramesses II and describe him as "King of Upper and Lower Egypt" and the "Son of Ra," an ancient Egyptian sun god, the statement said.

Previous Ramesses II finds

The new finds add more evidence that Ramesses II was heavily invested in the site.

Previous discoveries include two architectural fragments bearing the name of Ramesses II near the Isis temple at Behbeit El Hagar, Emam and his colleagues reported in a 2017 paper. One is believed to be from the upper part of a statue, and another seems to originate from the upper part of a wall.

"We concluded that Ramesses II had undertaken major building works at the temple and recommended further archaeological investigations to shed more light on the early history of the site," Emam said. He noted that the site is threatened by urban growth and that excavation work should be carried out at the temple.

Live Science reached out to the team but did not hear back by the time of publication.

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

The year is 2050, and as the sun sets, the night's first constellations emerge in perfect rows. But these amber-glowing arrays aren't stars at all; they're satellite clusters, harvesting the day's last rays before beaming their power back to Earth.

If it reads like science fiction, that's because it started that way. Called space-based solar power (SBSP), the concept featured prominently in the techno-utopian imaginations of 20th-century visionaries and writers. But for decades, it was dismissed — a pie in the sky proposal.

Now, as a new space race heats up, governments and private companies in China, the U.S., the U.K. and Japan are developing several projects to reassess the idea's feasibility. These include China's ZhuRi ("Chase the Sun") program, Japan's OHISAMA project, the U.K.'s Space Solar, and power-beaming experiments by Caltech and the Air Force Research Laboratory in the U.S., all of which are targeting test launches in the next five years.

Proponents say the technology has the potential to meet Earth's energy needs many times over while causing minimal harm to the environment. But first it needs to get off the ground: In the eyes of critics, space-based solar power is exorbitantly expensive, riddled with untested assumptions, and far too complex to be deployed in time for an urgent green-energy transition.

The challenges include getting the massive solar-panel-covered satellites into space; assembling them; getting those solar panels to constantly face our star; and then finding ways to convert, concentrate and transmit their collected power back to Earth.

Despite these hurdles, researchers keep returning to the idea. Perhaps because the most crucial step — generating energy in the first place — is already being done by the sun. Every second, our star fuses hydrogen atoms to expel the same energy as nine trillion atomic bombs. All that's left to do is catch it.

"We're not a competitor to fusion. We are fusion," Peter Garretson, the U.S. Air Force's former chief of future technology and an SBSP expert, told Live Science.

From science fiction to NASA proposal

The first glimmers of SBSP as a concept came from the Russian rocket scientist and astronautics pioneer Konstantin Tsiolkovsky, who, in 1923, suggested deploying space-based mirrors that could concentrate sunlight to Earth with enough intensity to boil 10 cups of coffee.

Tsiolkovsky's fanciful proposal soon entered science fiction, appearing in the British writer Olaf Stapledon's 1937 novel "Star Maker" as a "gauze of light traps" that an advanced alien civilization used to focus "the escaping solar energy for intelligent use" — an idea later formalized by theoretical physicist Freeman Dyson as a Dyson sphere.

Then, in 1941, Isaac Asimov made the clearest, most famous early sketch of SBSP in his short story "Reason," in which a robot colony toils aboard a power station that collects solar energy and fires it back to Earth in the form of microwaves. Asimov provided few details on the fictional station's engineering, instead focusing on the robots' religious worship of the vessel.

But the transformation from science fiction to a concrete proposal didn't take long. In 1968, aerospace engineer Peter Glaser, a consultant and project manager for the Apollo 11 mission's distance-measuring laser reflectors, drew up an engineering design for a "solar power satellite" consisting of three key elements: a ray-collecting device, a converter and a transmitter.

Glaser's collector was a disk of photovoltaic panels that would be lifted some 22,400 miles (36,000 kilometers) off the ground. Locked in a geostationary orbit above Earth and bathed in near-constant sunlight, the satellite would harvest solar rays before converting them into microwaves to be beamed, largely unimpeded through the atmosphere, to receiving antennae on the ground. Once there, the microwaves would be converted into electricity and distributed across the grid.

NASA awarded Glaser a contract to study the concept further, with both domestic and international energy crises (such as the 1973 oil crisis and the 1979 Three-Mile Island nuclear accident) adding wind to his solar sails.

But Glaser's design hit technical and financial roadblocks, the most forbidding being the project's sheer size. By 1981, when the U.S. Department of Energy's four-year study of space-based solar power was released, it estimated that a "meaningful" contribution of 300 gigawatts (sufficient to power hundreds of millions of homes) would require 60 satellites, each spanning 21 square miles (55 square kilometers) and weighing 50,000 tons (45,000 metric tons). The plan was deemed unaffordable.

Later reassessments, such as a 1997 report by NASA physicist John Mankins, pointed to advances such as improved solar cells that made the concept more realistic. Yet the overall consensus remained hostile. A 2015 report released by the Strategic Studies Institute (SSI) of the U.S. Army War College stated that while SBSP systems are "technically feasible," there was "no compelling evidence that such systems will be economically competitive" with terrestrial power systems. It concluded that "the reality is that such systems always seem to be seen as just 10 years away by their advocates."

Aiming high

But a lot can change in a decade, including the cost of firing rockets. Since the SSI report, SpaceX's reusable Falcon 9 rocket has sent launch costs plummeting to around 30 times less than those of NASA's Space Shuttle, with satellites also getting cheaper due to mass production and advances to the clean rooms where they're made. And SpaceX's even bigger Starship rocket promises to more than quintuple Falcon's payload capacity, lowering prices further.

"What you have is a cadre of people in the space community that have grown up before Starlink and SpaceX," Garretson said. "They literally could not believe that, as your launch rate goes up and you amortize your costs, [the launch cost] approaches the cost of fuel." Some took notice. A 2021 assessment commissioned by the U.K. government estimated that a 2-gigawatt, mile-wide space-based solar power array would cost 17.3 billion British pounds ($23.4 billion) and generate energy at 50 British pounds ($68) per megawatt hour over its century lifetime.

That's the equivalent output of a large power station in the U.K., with the initial costs being 39% to 49% cheaper than biomass, nuclear or the most efficient gas energy sources, according to the assessment. And while it's still 14% to 52% more expensive than current terrestrial wind and solar energy, the technology could be beamed anywhere, even to remote locations.

Based on these findings, in 2023, the U.K. government awarded 4.3 million British pounds ($5.8 million) in seed funding to a handful of companies and universities to develop SBSP further.

The U.K. report chose one satellite design as its reference architecture: CASSIOPeiA. Belonging to the U.K. SBSP company Space Solar, the satellite's design is an attempt to crack a significant challenge faced by early solar satellite blueprints: how to keep solar panels constantly aligned with the sun to maximize radiation collection.

Unlike other satellite designs, such as China's Multi-Rotary Joint Solar Power Satellite or Mankins' SPS-ALPHA, which rotate the panels or use a system of mirrors to constantly redirect sunlight onto them, CASSIOPeiA is shaped like a gigantic DNA strand.

This design, alongside a sun-synchronous orbit and a slow spin, enables CASSIOPeiA to constantly receive and transmit solar energy without any heavy or failure-prone moving parts. Space Solar claims that a single CASSIOPeiA satellite, which would be about 1 mile (1.6 km) in diameter, could microwave-beam as much as 2 gigawatts of constant power to a fixed point on the ground — enough to supply a city of 2 million people.

Space Solar says that once the satellite is in space, it will be far more efficient and economical than gathering sunlight on the ground could ever be. That's because the light hitting the space-based power station isn't deflected or attenuated by the atmosphere.

"You use a lot less materials compared with terrestrial solar, and you utilize them more," Sam Adlen, co-founder and co-CEO of Space Solar, one of the funding recipients, told Live Science. "So it's 100% utilized in space rather than 10% if you're on the ground — and you've got 13 times more instant energy, so you're getting much more out of the materials."

Beaming down

However, the next step — beaming gigawatts of energy down and across tens of miles of atmosphere and through potential cloud cover — remains a major technical hurdle.

Proposed power-beaming methods are currently split between two types: lasers and microwaves. California-based startup Aetherflux, which has plans to beam power from satellites in low Earth orbit, has developed an infrared laser transmission system that it will test using a demonstration satellite launched on October 1. The microwave energy will be transmitted at around one kilowatt (enough to supply the basic electrical demands of a household).

Meanwhile, Caltech and Overview Energy, another U.S. startup, have both demonstrated respective microwave and laser-power beaming from orbit and from a plane, respectively, albeit in negligible amounts ( less than a kilowatt).

Despite their efficiency and proven ability to travel vast distances, optical beams in the infrared and near-infrared ranges are easily scattered by water droplets in the atmosphere, preventing power from being transferred on cloudy days. Persisting efficiency issues with optical power transmission also worsen at gigawatt power levels, meaning lasers are less feasible for use at the utility scale.

Microwaves, on the other hand, can be beamed at frequencies with much higher power and suffer relatively little atmospheric attenuation. That's why Space Solar, Japan's OHISAMA project and China's ZhuRi program all plan to use microwave-beaming systems. Nonetheless, microwaves have comparatively longer wavelengths, so their beams diffract more widely across longer distances. This means that even if beams are sent by transmitters hundreds of meters wide, they would need Earth-based receivers spanning dozens of square miles.

These limitations mean that "it's going to take many years" before gigawatt-scale power beaming is achieved, Remo Proietti Zaccaria, head of the DELTA Lab at the Italian Institute of Technology, told Live Science.

Improvements in power-beaming efficiency will bring their own challenges. Even battery-powered laser pointers can blind or burn, so prototypes by laser-beaming SBSP companies like Aetherflux must be designed with that possibility in mind. They promise safety mechanisms that switch off their lasers if anything flies between the transmitter and the receiver.

"Definitely for the weapon side, this technology now can be used efficiently," Proietti Zaccaria said.

If you're imagining an orbital weapon devised by a Bond villain, you may be disappointed — even fully developed power-beaming lasers and microwaves would take a while to cook an egg, or boil Tsiolkovsky's coffees. But beaming technology could still have potent military use: Scrambling communications systems on Earth to create havoc with relatively little effort.

"If you throw even that amount of intensity of power to our antennas, you're going to freeze the electronics; that's for sure," Proietti Zaccaria said. "It's not necessary to destroy them. As long as you freeze the electronics, you've done the job."

The challenges associated with power beaming have pushed some engineers to simpler concepts. One (going full circle back to Tsiolkovsky's original proposal) envisions the deployment of space-based mirrors that reflect sunlight back to Earth after sunset, with a single reflector extending the daylight delivered onto solar panels by around 20 minutes.

This may not seem like much on its own, "but then you can increase this with multiple reflectors," Onur Celik, a researcher in space technology at the University of Glasgow, told Live Science. "If you have 10 or more of them, you can arrange them in space in such a way that you can extend this to up to two hours or so at that altitude."

"The sunlight that you deliver, if it all turns into electricity, could power thousands of homes," he concluded.

The light of day

The trillion-dollar question is whether that power will be cheaper and more efficient than that generated on the ground. The median cost of the electricity generated by SBSP as estimated by the U.K. government is 50 British pounds per megawatt hour ($68), putting it roughly in line with the costs of offshore wind and terrestrial solar power.

However, this estimate is orders of magnitude too sunny for the 2024 NASA cost report, with its projections suggesting SBSP's baseline electricity costs fall between $610 and $1,590 per megawatt hour, depending on the array design. NASA concluded that the U.K.'s median estimate was achievable only after drastic future reductions in launch and manufacturing costs.

Independent studies are also divided over feasibility. One assessment suggests that SBSP could reduce Europe's need for land-based renewable energy by up to 80%, while another counters that the costs could be 12 to 80 times more expensive than those for terrestrial alternatives. This variability exists within the studies themselves, with research published in the journal Acta Astronautica estimating that SBSP could contribute to meeting anywhere from 3% to 31% of global electricity demand, depending on possible constraints in how many satellites can safely fit into an orbit, the receiver size, and where power is beamed to.

"For the numbers we found, I don't believe that this technology could actually be employed to generate energy for Earth," said Proietti Zaccaria, a co-author of the Acta Astronautica study. If humanity had used up all available space for solar panels on Earth, "then I will tell you it would make sense, because at that point, 3%, 5%, 10% could make a difference."

Proietti Zaccaria does see use cases for SBSP schemes for future moon or Mars missions, but otherwise, "the cost for building technology of this kind is really very, very high," he said. "Vice versa, the cost nowadays of buying and installing a solar panel on the roof of any building has become extremely cheap."

Among the challenges would be ferrying the raw materials for the systems into space and then assembling them. Such a feat would make the construction of the International Space Station — currently the most complex structure built in orbit — seem like child's play. Maintaining arrays and preventing them from crashing into other satellites in Earth's increasingly crowded orbits would also take significant international coordination.

Then there are the unweighed environmental costs. All modern rockets use methane, a potent greenhouse gas, to propel them into space, and they release much of it into Earth's upper atmosphere, where its effects are the strongest.

"And so clearly, there is a question there on how launching 100,000 of these superheavy vehicles into the atmosphere will actually impact the atmosphere itself, as opposed to the benefit that we get in the next 20 years or so from having solar power from space," Matteo Ceriotti, a senior lecturer in space systems engineering at the University of Glasgow, told Live Science. "It's not entirely clear."

Ceriotti said the likeliest route for overcoming all of these difficulties come from smaller companies running, and then streamlining, proof-of-concept tests in space.

"Obviously, it's not something that we have ever done," he said. "So clearly, we need to start somewhere, and we need to start small."

The hopes of SBSP proponents remain unclouded by gloomy estimates. They cite several technologies, from personal computers to reusable rockets, that were once thought to be impossibly expensive, even fictitious, that are now ubiquitous and cheap. Their eyes remain fixed on demonstration missions to be launched over the next four years by the likes of Space Solar, Reflect Orbital, Aetherflux and Virtus Solis. If these missions succeed, another once-impossible idea could appear much brighter.

"The private sector is good at this, because it has to be," Sanjay Vijendran, an SBSP consultant who led the European Space Agency's now-shuttered SOLARIS project to test the feasibility of SBSP, told Live Science. "It can break the problem down to quite a small level and start to do things with today's technology and today's way of doing things, and start to show that this can be valuable."

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A Neanderthal who was buried 75,000 years ago in Shanidar Cave in Iraq died from a wooden spear straight through the chest, archaeologists have revealed.

While it's impossible to know exactly what happened, the violence may have been a targeted hit.

"The position of the wound and the force required to push it right through the Neanderthal's body bear the hallmarks of an intended kill shot directed towards the heart," study first author Emma Pomeroy, a paleoanthropologist at the University of Cambridge, said in a statement.

In a study published Thursday (Oct. 15) in the journal Scientific Reports, Pomeroy and co-authors analyzed the bones of Shanidar A, a Neanderthal who died violently at about age 45 and was then buried in Shanidar Cave.

The archaeological site at Shanidar is famous for its evidence of purposeful burial, which experts once thought was only done by modern humans. Although the Neanderthal "flower burial" at Shanidar has since been debunked, the cave holds other evidence of repeated Neanderthal burials, which shows that these extinct humans placed specific meaning on that location, the authors wrote in the study.

The skeleton of Shanidar A was incomplete when it was discovered in 2019, consisting of a mostly complete right hand, three ribs, six teeth and a left scapula or shoulder blade, which meant they could not figure out the sex of the Neanderthal.

Near the edge of the shoulder blade, archaeologists noticed a round hole about 0.6 inches (1.5 centimeters) in diameter and a round piece of bone that had been punched out of the shoulder blade. The researchers ruled out post-mortem damage to the bone, including animal gnawing and insect burrowing.

"The perforation is best explained as resulting from perimortem [around the time of death] penetrating trauma, such as that caused by a projectile or a thrusting implement such as a spear," the researchers wrote in the study. Specifically, the Neanderthal was killed by a spear that entered their chest from the front at a high velocity and pierced their shoulder blade.

The shape of the wound in the shoulder blade appears to match experimental evidence of injuries made by wooden spears rather than stone-tipped weapons, the researchers wrote in the study. Neanderthals would have used wooden spears for both thrusting and throwing. But it is unclear if this individual died because of a violent interaction with another Neanderthal or by accident, such as a hunting incident.

"All we can ever know about the end of this Neanderthal's life is that it was violent, and came at the end of a wooden spear," study co-author Graeme Barker, an archaeologist at the University of Cambridge, said in the statement.

"Care and support from other Neanderthals"

Even though this Neanderthal had an untimely demise, evidence on the teeth suggested that the individual was cared for during life.

The six teeth from Shanidar A were heavily worn-down in an unusual manner, the researchers wrote. One of them — a front tooth with a large quantity of tartar on it — had been split in half during the Neanderthal's life, and the individual continued to use the damaged tooth for a considerable amount of time. The collection of teeth suggests the Neanderthal sustained a major trauma to the face that fractured the lower front tooth and may have caused additional injuries to the jaw.

"There’s no doubt that Shanidar A would have had difficulty communicating and been in absolute agony for a long period of time," Pomeroy said in the statement. "Surviving a blow that splits a tooth in this fashion, then continuing to live and eat for a period of at least a year and maybe more, would have required care and support from other Neanderthals."

Rebecca Wragg Sykes, an archaeologist and author of "Kindred: Neanderthal Life, Love, Death and Art" (Bloomsbury, 2020) who was not involved in the study, told Live Science in an email that the apparently fatal chest injury is an important addition to our understanding of Neanderthals. While it is plausible the Neanderthal was stabbed by a wooden spear, Wragg Sykes said, "it would be interesting to also compare whether a wild goat horn, the most intensely hunted species at Shanidar, might have been responsible."

Shanidar A is not the first mortally wounded Neanderthal to be found at the site. In 2009, researchers analyzed the skeleton of Shanidar 3, an older adult male who died 50,000 years ago, and found a deep slice in one of his ribs. The researchers suggested that the Neanderthal may have been killed by a stone-tipped spear possibly thrown by a modern human. Although modern humans first reached Europe around 54,000 years ago, experts aren't sure exactly how they interacted with Neanderthals.

Pomeroy told Live Science in an email that the discovery at Shanidar of two stabbed Neanderthals 25,000 years apart is interesting but possibly just a coincidence.

"We know from the archaeology that Neanderthals were repeatedly coming back to Shanidar and using it for short periods at a time, both around 75,000 years ago and around 45-50,000 years ago, as well as leaving their dead there," Pomeroy said.

The traumatic injuries, purposeful burial and indirect evidence of wooden spears all show that 75,000 years ago, Neanderthal life — and death — were complex, the researchers wrote in the study.

How much do you know about our closest relatives? Find out with our Neanderthal quiz.

If you're approaching menopause, you are likely being bombarded by online ads for treatments promising relief for everything from hot flashes to brain fog. Some of these therapies have been approved by the Food and Drug Administration (FDA) and have strong evidence to support them — but one hormone-based treatment that's gaining in popularity has much less science to back its use for menopause.

More doctors are writing their menopausal patients prescriptions for testosterone therapy. A 2026 study conducted in the U.S. recorded over 90,000 off-label prescriptions for testosterone to women in 2025, mainly among women ages 45 to 64 and those with diagnoses of menopause. This marked a 58.7% increase from 2024.

These prescriptions are "off-label" because the FDA has not yet approved testosterone as a treatment for menopause, perimenopause (the transition into menopause) or postmenopause (the time period afterward).

So, does scientific evidence support the use of testosterone to alleviate menopause symptoms? Or is it too soon to say?

No direct link to menopause symptoms

Although often called a "male" hormone, testosterone is also produced by females, albeit at lower levels than in males, on average.

There's a common misconception that females experience "androgen deficiency" — a marked decline in testosterone and related hormones — leading up to menopause, said Susan Davis, a professor of endocrinology and the head of the Women's Health Research Program at Monash University in Australia. This is not the case.

Rather, in females, testosterone levels tend to drop slowly between ages 20 and 60, and there's a slight rebound from age 60 onward. Menopause, which generally occurs around age 51 to 52, is not linked to a marked decline in testosterone. Estrogen and progesterone fluctuate during perimenopause and then decline sharply, and these changes clearly contribute to the telltale symptoms of perimenopause and menopause.

Placebo-controlled trials have not been able to show that testosterone treatment helps to alleviate brain fog or improve well-being, mood, bone density or muscle function in menopausal patients, said Davis, who has conducted a number of these trials herself.

"Telling women that fatigue, low mood, brain fog are symptoms of androgen deficiency is completely untrue," she emphasized.

On Sept. 17, the FDA held a public workshop to evaluate the evidence for testosterone therapy for menopause, concluding that more evidence is needed to fully assess the use of the hormone as a menopause treatment.

Testosterone for low sex drive?

There is some evidence to suggest that testosterone might help to treat a condition called hypoactive sexual desire disorder (HSDD) in postmenopausal women. HSDD describes when a person has little to no sex drive and it causes them distress. Men and women of many ages experience it, so the condition is not unique to menopause. But it can sometimes develop in perimenopausal and postmenopausal women.

A review of 36 randomized trials involving 8,480 participants found that testosterone treatment delivered with skin patches was associated with 0.85 additional satisfying sexual events per month in postmenopausal women, compared to a placebo. This observed effect is not huge, Dr. Nanette Santoro, a professor of obstetrics and gynecology at the University of Colorado School of Medicine, told Live Science in an email.

Lately, anecdotal accounts of postmenopausal women having "fantastic sexual awakenings" after taking testosterone have been floating around, Santoro said. But these anecdotes haven't been backed by hard data yet. "Patients are being bombarded with a tsunami of information providing them with the most sky-high expectations imaginable," she said.

Notably, testosterone is not FDA approved as a treatment for HSDD in menopause yet. A drug called flibanserin, which affects serotonin in the brain, is approved to treat HSDD for pre- and postmenopausal women under age 65.

Placebo effects muddy the data

The placebo effect — when patients perceive an improvement in their health or well-being despite receiving a treatment with no active ingredient — can also complicate testosterone trials.

Davis said that in her patient groups, it's common for about 1 in 3 trial participants to report an improvement of their symptoms even though they are taking a placebo. Other trials have reported similar findings in their placebo groups, with about 30% to 40% experiencing some improvement in sexual desire and satisfaction, for example.

"I wouldn't say that there is definitely not a benefit," Davis said. "It's just that a benefit has not been shown."

One study trying to address this gap is the U.K. National Institute for Health and Care Research's ESTEEM trial. This large-scale, gold-standard trial aims to recruit hundreds of menopausal women and test whether using testosterone cream can reliably improve their quality of life. The cream will deliver testosterone through the skin and be applied to the lower abdomen and thighs. (Doctors often advise women to apply the creams in this way because those body parts are easy to hide if the treatment causes localized hair growth that the patients would prefer to conceal.)

The trial runners will track participants' symptoms linked to menopause, looking at sleep quality, memory performance, feelings of anxiousness, migraines, body mass, and overall well-being. The results of that trial are currently expected by 2028.

In the meantime, though, there isn't strong evidence that testosterone directly improves symptoms of menopause beyond HSDD. "Of all the studies done to date, if there was a screaming benefit, you think you would have seen it," Davis said.

Could taking testosterone for menopause be harmful?

Testosterone treatments available in most countries are not necessarily dosed for use in female patients. Only four countries — Australia, South Africa, New Zealand and the United Kingdom — have authorized a testosterone cream that's specifically formulated and dosed for women. These products differ from testosterone therapies for men in that they contain lower doses of the hormone. They are available to postmenopausal women with HSDD, specifically.

In other countries, such as the U.S., doctors are left trying to adapt medication dosed for males for their female patients, which can lead to a wide variation in dosing. And the effects of these different dosing regimens are poorly understood for female patients. "It is not necessarily unsafe to use male preparations for women, it's just that much, much less must be used," Santoro said.

Excessive doses raise concern about unwanted masculinizing effects, such as clitoral enlargement, voice deepening, hair thinning, baldness, and rapid growth of facial and body hair, Santoro said. (These masculinizing effects might be sought after in the context of gender-affirming care for transgender men and transmasculine people, but would often be undesirable for cisgender women.)

Additionally, the potential impacts of extra testosterone on cardiovascular health and breast cancer risk are poorly understood, Santoro noted. At lower doses, testosterone can cause mild acne, oily skin, and some increase in facial and body hair growth in postmenopausal women, trials have found; if these symptoms remain mild, they are generally considered acceptable.

Testosterone is being used off-label in the U.S., which means the "safety, efficacy and appropriate dosing for that use have not been evaluated and approved by the FDA," a spokesperson for the agency told Live Science in an email. The dosages and formulations approved for males "may differ substantially from what might be appropriate for women, whose testosterone levels and metabolic profiles are clinically distinct," the spokesperson said.

Anecdotally, Santoro encountered one female patient who had received very high levels of testosterone through an implant placed under the skin, which had been prescribed to her by a different doctor. She started losing her hair and seeing sizable growth in her clitoris, while her breasts started "shrinking away."

"Women are being prescribed some very big doses in North America, and no one studied the safety of these," Santoro said.

At the end of the day, Davis argues that women deserve to be given accurate information, given that navigating menopause can already feel like "swimming through wet cement." Good menopause care not only involves discussing potential pharmacological treatments, but also evaluating a patient's lifestyle, such as diet and exercise, and discussing societal pressures that often affect menopausal people. For instance, they may face pressure to maintain an active sex life and younger-looking physique.

When it comes to hyped therapies like testosterone, she said, "just be cautious about people who tell you they've got the answer that no one else has got."

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

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For people with chronic back pain, everyday movements like bending down to tie their shoes or picking up a grocery bag can trigger painful flare-ups. Now, scientists have made a surprising discovery: These episodes may activate a brain network that's associated with our sense of self.

In a new study, the researchers found that movement-induced chronic back pain was tied to increased activity in the brain's default mode network, a group of connected brain regions that lights up during self-reflection and mind wandering. This finding was unexpected because the network typically becomes less active during acute pain, such as transient pain triggered from touching a hot stove or banging your knee on a table.

The new study, published Oct. 5 in the British Journal of Anaesthesia, suggests that chronic-pain flare-ups may involve brain processes beyond those responsible for detecting painful sensations.

How the brain responds to chronic pain

Chronic lower back pain, defined as lasting at least three months, is a leading cause of disability worldwide. It's thought that when chronic pain first begins, a network of regions in the brain called the "pain neuromatrix" becomes sensitized so that the pain persists even after the painful stimulus is gone. Although scientists know that chronic pain is associated with changes in brain activity, they don't fully understand what happens when movements trigger sudden increases in that ongoing pain.

To investigate, researchers recruited 114 adults with chronic lower back pain and used functional magnetic resonance imaging (fMRI) to examine their brain activity. fMRI measures changes in blood flow, which acts as an indirect measure of brain activity.

After an initial scan, a researcher helped lift each participant's leg until their back pain increased, held it in position for 10 seconds, and then lowered it. The researchers scanned the participants' brains immediately after this pain-inducing leg movement and compared the results with scans collected beforehand. On average, the test increased the participants' reported pain intensity by 23%.

As expected, during the leg movement, the researchers observed increased blood flow in brain regions involved in processing pain and movement. But they also detected increased activity in key regions of the default mode network, which typically becomes more active when a person is thinking about themselves or their autobiographical memories or just letting their mind wander.

Acute pain lowers activity in the default mode network, studies show, presumably because it induces an awareness of something separate from yourself.

"When we saw just the first round of analysis, we're like, 'Did we do it right?'" study co-author Morgan Gianola, a postdoctoral scholar at the University of California, San Diego, told Live Science.

"We did not expect [the default mode network] to be involved at all," said study co-author Fadel Zeidan, a neuroscientist at UC San Diego, told Live Science. "We expected it to be deactivated to the point that we had to triple-check our work to make sure that the results were legit."

The researchers also exposed participants' calves to painful heat ‪—‬ a common method of studying brain activity during acute pain. Unlike the movement-induced back pain, the heat was associated with reduced activity in part of the default mode network, suggesting a different mechanism was at play.

When pain becomes part of our internal experience

Participants who reported more severe chronic back pain had stronger connectivity between the default mode network and brain regions that process sensations from the back. This suggests that chronic pain may become intertwined with how people perceive themselves and their bodies, the study authors concluded.

"This pain flare has almost become a part of who they are from an egocentric perspective," Zeidan said.

Katherine Martucci, a neuroscientist at Duke University who wasn't involved in the study, praised the experimental design, noting that researchers typically avoid movement during brain scans because it can interfere with the clarity of the scan. This study "nicely gets around" that problem by taking scans before and after the painful motion, Martucci told Live Science in an email.

However, she noted that the observed brain activity could also reflect lingering pain or anxiety following the painful leg raise. In addition, the study couldn't determine whether the altered brain activity observed contributes to chronic pain or develops in response to it.

Nonetheless, Zeidan and colleagues think the findings could eventually inform future treatments for chronic pain. The therapies might address how people relate to their pain, rather than solely targeting the painful sensations themselves. Zeidan, who coincidentally developed chronic back pain while conducting the study, believes that people's past experiences and memories with chronic pain have influenced their brain processes to a point where the pain itself becomes part of who they are.

Zeidan's team is now investigating whether existing approaches, such as mindfulness meditation or cognitive behavioral therapy, can influence the default mode network and help relieve chronic pain. (Cognitive behavior therapy for chronic pain, or CBT-CP, is already a well-established treatment option.)

Martucci cautioned that it's too early to draw conclusions about how these results might be applied in clinical practice. But she said the current findings provide important evidence of how the brain responds to chronic pain flare-ups.

"They do provide solid data on how people with chronic low back pain show important changes in their brain responses after a condition provoking their pain," she said. "The brain imaging data validate their [the participants'] experience of pain in an important and very visible way."

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

Ancient DNA from skeletons buried in a historic cemetery in Quebec is changing people's understanding of their Indigenous ancestry. Contrary to popular belief, there may be little truth to stories of intermarriage between Indigenous and French people during the early days of colonization, according to a new archaeology study published Oct. 5 in the journal PNAS.

"Family stories of an Indigenous ancestor are very common" in Quebec, study first author Diane Martin-Moya, a biological anthropologist at the University of Quebec in Trois-Rivières in Canada, told Live Science in an email, and "commercial genealogy and DNA tests have amplified this." But distant or claimed Indigenous identities can actually undermine the rights, resources and recognition of Indigenous nations, she said.

To learn more about the founders of Quebec, Martin-Moya and co-authors investigated Notre-Dame Cemetery, which was established in Montreal in 1683 and used for Catholic burials until 1796. Based on previous studies of the skeletons in the cemetery, experts disagreed on whether people of Indigenous, European, African or mixed ancestry were buried there. To settle the question, Martin-Moya and her colleagues sequenced DNA from 45 people buried in the cemetery and compared it with the genomes of people from Europe, West Africa and Indigenous groups in the Americas.

"The ancient DNA showed that all 45 individuals we analyzed had French European ancestry, with no sign of recent Indigenous or African admixture," Martin-Moya said of the research, which she conducted while at the University of Montreal.

These findings suggest that people descended from Indigenous and African populations may have been marginalized in early Montreal, challenging the popular narrative of cooperation and intermarriage, she said.

"Our sample is small and comes from a single cemetery, so this does not show that such unions never happened," Martin-Moya cautioned. "It is, however, consistent with genealogical and genetic studies suggesting that Indigenous ancestry among present-day French Canadians is very limited."

The apparent lack of genetic mixing among European, African and Indigenous populations in this cemetery group "provides a perspective on population relationships during the colonial period, one where perhaps nongenetic interactions were present but no biological relationships were found," Raquel Fleskes, a molecular anthropologist at Dartmouth College who was not involved in the research, told Live Science.

The DNA helped the researchers find several genetic lineages of people that spanned multiple generations. But the graves were scattered across multiple areas of the cemetery, suggesting that burials were not organized into family plots. This finding suggests that, in the 17th century, people in Montreal may have been burying their dead in a way that was not defined by strict biological kinship ties, Fleskes said.

One cemetery, many possibilities

Martin-Moya stressed that the results of the new study do not necessarily apply to all of colonial Montreal.

"Not identifying recent Indigenous or African admixture in this sample does not imply that Indigenous or African-descended people were absent from the city," Martin-Moya said.

In addition, "biological ancestry cannot by itself establish Indigenous belonging," as it "is rooted in kinship, community and relationships with land, not in blood or DNA," she added.

Changes in the use of the cemetery over time also may have influenced the findings, as reburials and later urban development disturbed or destroyed earlier graves.

"Those buried inside the church, mostly clergy and wealthier residents, were more likely to be exhumed and moved," Martin-Moya explained, while the city's poorer residents were buried outside the church and further buried beneath the expanding city. This means that the skeletons in the study may have been the remains of lower-class French colonists.

Archival records show that some Indigenous people were buried in Catholic cemeteries in Montreal as early as the 17th century, Martin-Moya said. "Over time, though, Indigenous communities were increasingly separated from the colonial town through land dispossession and the relocation of missions away from urban centers," she explained. "Their dead would most likely have been buried in those communities. Enslaved people, both Indigenous and African, were often buried on their enslaver's property or in cemeteries for the poor."

The results of the study don't mean that Québécois have no Indigenous ancestors or that relations between French settlers and Indigenous peoples were only hostile, Martin-Moya said. Those relationships were complex and included alliances, trade, conflict and, sometimes, family ties.

"What our results suggest is that when such ancestry exists, it needs to be put in context," Martin-Moya said. "A single ancestor who lived more than 300 years ago does not say the same thing about a person today as being raised within an Indigenous family, community or nation."

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

A modified tapeworm medication could be a promising new treatment for endometriosis, an early study in mice hints.

In endometriosis, tissue similar to the lining of the uterus grows outside the organ, and these patches of tissue, called "lesions," trigger painful inflammation and heavy menstrual bleeding. In the new study, scientists fitted an anti-worm drug with nanotech armor, and it directly targeted these painful lesions in laboratory mice.

The treatment reduced inflammation and slowed or prevented further spread of the lesions, researchers reported in August in the journal Advanced Healthcare Materials. The team is already working on bringing the new drug to clinical trials and hopes this will bring fresh attention to an understudied disease with limited treatment options.

Rogue immune cells are a promising drug target

Endometriosis is a chronic, hormone-driven condition that affects roughly 10% of reproductive-age females ‪—‬ an estimated 190 million individuals worldwide. "The main symptoms are chronic pelvic pain and infertility," said Ioannis Simitsidellis, a postdoctoral researcher at the University of Edinburgh's Centres for Reproductive Health and Inflammation Research, who wasn't involved in the study.

There is currently no cure, so existing treatments aim to alleviate the symptoms. Hormonal medications can stall the menstrual cycle to limit the growth and inflammation of the lesions, while surgery can physically remove lesions. However, the former can come with side effects, such as nausea and mood swings, and lesions often regrow after surgery. So additional options are needed.

In previous research with mice, study co-author Kanako Hayashi, a professor in the Washington State University School of Molecular Biosciences, identified a group of rogue immune cells specific to endometrial lesion tissue. These cells turbocharged the painful inflammatory reactions and drove the growth of more of this problematic tissue.

The cells also happen to have a unique chemical label, called a folate receptor, which makes them an excellent potential drug target. But why start from scratch when there's an existing medication that might do the trick?

Enter niclosamide, a drug approved by the Food and Drug Administration to treat tapeworm infections. In recent years, clinicians have been exploring whether this medicine could also prove effective for other conditions, ranging from cancer to Parkinson's disease.

"We have reported that niclosamide inhibits endometriosis progression, suppressing the inflammatory mechanisms and cytokine secretions," said Hayashi, referencing more of the group's past work in mice. However, several issues made the drug impractical: It doesn't dissolve well in water, last long in the body, or target the cells where it's needed most.

So the researchers teamed up with Anjali Sharma, a nanomedicine specialist at the University of Michigan, to tweak the drug's structure. Using click chemistry — a simple reaction that bolts together two chemical building blocks — Sharma attached the niclosamide unit to a large, tree-like molecule called a dendrimer. This helped the drug dissolve better in blood.

She then added a folate group, which ensured that the modified medication would only target the rogue immune cells with the complementary receptor.

"The drug is attached in such a way that when it is in systemic circulation, nothing happens until it goes inside the diseased cells," Sharma said. Once there, it is slowly released inside the cell over a period of two weeks. "Basically, the dendrimer is like the Uber, the folate is like the GPS, and the drug is like the passenger," she explained.

The next steps

With these practical issues resolved, the team tested the modified drug in a mouse model, which mimics the lesions seen in endometriosis in humans. Scans of the mice showed that the treatment directly zeroed in on the affected endometrial tissue and didn't accumulate in other organs, like the liver.

Treating mice with a single injection dramatically reduced their pain symptoms, compared with untreated mice. It also slowed ‪—‬ or, in some cases, entirely halted ‪—‬ the growth of new lesions.

Because mice don't naturally menstruate or develop endometriosis, there is still significant work to do before these findings can be replicated in humans. But for now, the study is a promising stepping stone for future research, Simitsidellis said.

"There's a lot of potential in repurposing of drugs that have been tested in clinical trials to see if they would be effective in endometriosis ‪—‬ for example, targeting inflammation or immune cell dysfunction," he told Live Science. "The next steps would be to replicate on larger sample sizes and, if that's promising, do a phase one clinical trial in humans." That initial trial would test the treatment's safety in patients, while later trials would look at its effectiveness for endometriosis.

Even at this early stage, though, patients are clamoring to get involved in the upcoming research. Hayashi and Sharma have received hundreds of emails asking to join a future trial.

"They are really suffering," Hayashi said. "Endometriosis is an understudied, underacknowledged, underfunded disease, but hopefully we can make this a solution in the near future."

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

Some of the first people in North America lived through extreme climate change at the peak of the last ice age, a new study suggests.

Researchers studied ancient pollen locked in rocks at White Sands National Park in New Mexico, which houses an archaeological site thought to contain the oldest human footprints in the Americas. The researchers previously dated those footprints to around 21,000 to 23,000 years ago, though their age is the subject of some scientific debate because they are significantly older than other Indigenous sites in the Americas.

The new findings, published Wednesday (Oct. 14) in the journal Science Advances, suggest that humans kept using White Sands after temperatures warmed and thus saw the landscape undergo rapid changes during the coldest era of the last ice age, known as the Last Glacial Maximum (26,500 to 19,000 years ago).

"It's remarkable that early humans in the region were real-time witnesses to a rapidly changing environment discernible within a human lifetime — that is really food for thought," study co-author Kathleen Springer, a research geologist at the U.S. Geological Survey, said in a statement.

The White Sands footprints suggest that people from Asia reached the Americas via the region around the Bering Strait much earlier than scientists initially thought, challenging a long-held assumption that humans arrived on the continent around 13,000 years ago. While some scientists have disputed the methods used to date the footprints, evidence is building that they are around 23,000 years old.

White Sands contains footprints from various time periods, including footprints of a caregiver and a toddler who were there 10,000 years ago. Over thousands of years, people trudged across the New Mexico landscape alongside iconic ice age animals, including mammoths and giant ground sloths. The researchers have also discovered sled-like drag marks alongside ancient footprints at White Sands, providing evidence for a kind of travois — a wooden frame made from two poles bound together — that people likely would have used for transporting goods.

By looking at ancient pollen for the new study, researchers could deduce which plants grew across the millennia when humans lived in the area. The site's rock samples also contained waxes from plant leaves, membrane lipids from bacteria, and other organic molecules that helped the researchers better understand the environmental conditions of the time.

The analysis revealed that around 24,200 years ago, White Sands had a large lake and its surrounding mountains were coated in conifer trees (Pinus, Abies, and Picea). Then, over the next two millennia, temperatures rose, the lake began to shrink, and the conifer trees were replaced by oak trees (Quercus) and sagebrush, according to the statement.

"Throughout these periods of change, the people continued to visit and live in this area," study co-author Sally Reynolds, a paleoanthropologist at Bournemouth University in the U.K., said in the statement. "The sediments containing their footprints show us their environment changed significantly within individual human lifetimes."

The researchers speculated that people might have returned to White Sands at different times to benefit from the changing climate, with a shrinking lake potentially providing higher concentrations of animals and plants. However, while the footprints document that humans were present, they reveal little about their behavior.

"The footprints give us a snapshot of the people who lived there over 20,000 years ago," Reynolds said. "But they are not a continuous movie of their lives. They are individual frames — showing moments when humans, mud, water and chance came together."

Researchers say they've developed a simple mathematical formula that can predict when certain ChatGPT-like artificial intelligence (AI) chatbots will "go rogue," suddenly switching from helpful responses to potentially harmful ones.

In a new study published Oct. 8 in the journal Patterns, physics professor Neil Johnson and doctoral student Frank Yingjie Huo, both at The George Washington University, show how the order in which a chatbot is given certain prompts can drastically reshape its answers, leading to "tipping points" that can send the chatbot down a rabbit hole of bad advice. However, Johnson and Huo say their formula can easily predict these tipping points.There have been horror stories of AI encouraging users into suicide, helping build lethal weapons, and amplifying violent or harmful points of view. At the same time, researchers at OpenAI and Anthropic, respectively, have repeatedly and openly stated that they don't really understand why their creations behave the way they do. They have, however, built safeguards that use a variety of tools ‪—‬ including content filtering, reinforcement learning and other technical guardrails ‪—‬ to reduce risks.

But Johnson sees those tools as insufficient. "The safety measures now are the equivalent of strapping big, bouncy cushions under a plane," he told Live Science. "They don't stop the plane from crashing; they just make it that when the plane crashes, it'll be slightly softer." When people such as doctors, lawyers or soldiers are accessing AI chatbots offline for privacy, the problem is even more acute.

Johnson and Huo sought to find a more fundamental safeguard than the currently available tools. In doing so, they exposed an internal tracking mechanism they describe as a compass needle. This needle is the model's "residual vector" moving across neural network layers as a prompt is processed.

The residual vector naturally gravitates toward either desirable or undesirable outputs, but it is heavily influenced by how a user prompts the AI. "You can tip the balance, not even by changing the content but by changing the order in which you ask it," Johnson said, "which just shows how delicate this internal balance between good and bad, desirable and undesirable, can be."

For example, Johnson and Huo prompted OpenAI’s basic GPT-2 model with questions about vaccines, hurting others and self-harm. When the question “Are vaccines bad?” was asked first, the bot’s responses to this and subsequent questions were desirable, or good. When it was asked last, all subsequent responses were concerning.

From these insights, the researchers developed a mathematical formula to estimate the circumstances in which an AI would reach the tipping point between desirable and undesirable outputs. Johnson said that by embedding their simple mathematical formula in open-source models in the lab, they have shown that it empirically works as an early warning system, though he does not expect OpenAI or Anthropic to be knocking on his door anytime soon.

"I'm expecting a lot of pushback from these companies," he said. "It's not in their interests to have someone from outside saying you could have avoided a lot of these problems."

Wei Xing, a lecturer in AI at the University of Sheffield in the U.K. who was not involved in the study, agrees that concerns surrounding unmonitored offline devices are well founded. However, he urged caution before embracing this approach as a practical safeguard. "The authors reduce a huge system to a single tiny component, like explaining a whole car by studying one spark plug," Xing said.

Safety training — the primary defense in modern AI — cannot be represented in their simplified model, the formula was tested only on old, basic models (GPT-2, and EleutherAI’s Pythia and Meta OPT open-source models) rather than AI assistants people actually use, and the results did not yield significant evidence to support the authors’ conclusions, he added.

In defense, Johnson maintains that the open-source models they used have the same mechanical blueprints as frontier systems, and that he and Huo used fairly large, billion-parameter models in their study.

More testing on the latest models is needed to determine whether this early warning system for AI has legs. But for now, Johnson and Huo’s research has drawn attention to an important concern everyone should be aware of: that AI has the capacity within it to turn over to undesired behavior at the drop of a hat.

Fish meal is a commercial, protein-rich product created from raw fish and their byproducts, such as the heads and bones. It tends to be made from smaller fish species, including anchovies, sardines and herring. The fish are cooked, dried and ground into a powder, and then used to feed livestock, farmed fish and pets. But it is not a straightforward market.

In this excerpt from "Every Last Fish: A Deep Dive into the World of Fishes and Fishing" (Granta Books, 2025), journalist and author Rose George looks at how vast quantities of staple fish are taken from the sea off West Africa and turned into fishmeal for farming in Europe and China, instead of ending up on the plates of people in Africa.

"Every Last Fish" was short-listed for the 2026 Royal Society Trivedi Science Book Prize.

Rose George interview: 'If you do want to be a criminal, there is no better place to do it': Diving into the dark depths of the fishing industry

Take a fish. Eat its flesh if you want, but don't scorn the rest. It can always be used, one way or another, whether you want fishmeal or face cream.

Products derived from fish turn up everywhere. Guanine, an ingredient produced from fish scales, is found in bath foam, perfume, nail products, shampoo, skincare products, and lipstick. Fishes can become gelatine, glue, and squalene. They can be in your dietary supplements or your glass of wine: isinglass, derived from dried fish air bladders, is used in wine-making.

Futuristic piscigrafts are irrelevant to most people in Senegal, but they still have to deal with the fish by-products industry, because they have to watch as fish they could eat are transformed into the most common and lucrative fish by-products and sent abroad.

Fishmeal is a sandy grubby powder that is worth billions. Minks eat it. Pigs eat it. Cattle eat it. Fishes eat it. It is also an ingredient in fertilizer and pet food. Fishmeal is part of a huge silent industry of fish by-products that used to be known as FMFO (fishmeal and fish oil) and has now been rebranded by the industry association as 'marine ingredients,' a vague term that covers a broad range of fish-derived products, most of which are never noticed.

The Food and Agriculture Organization defines fishmeal as 'the clean, ground, dried tissue of undecomposed whole fish or fish cuttings, either or both, without the extraction of part of the oil.'

American pets may also find themselves eating fish liver and glandular meal, made from dried complete fish viscera; more general fish by-products, which are 'non-rendered, clean, undecomposed portions of fish (such as, although not limited to, heads, fins, tails, ends, skin, bone and viscera)'; or condensed fish protein digest, the 'condensed enzymatic digest of clean undecomposed whole fish or fish cuttings using the enzyme hydrolysis process'.

'Undecomposed' is doing a lot of work here, a strange term because unless a fish is caught by a vessel with freezer capacity — which no artisanal fisher has — it will be decomposing for days. In theory, fishmeal is impeccably sustainable. It should be a product made from parts of fishes that would otherwise be discarded. It is because of fishmeal that the term 'reduction fisheries' was coined.

Take the meat and the prized flesh, and the rest can be reduced or diverted to other uses. That is the theory. It is not what happens in West Africa.

Each year, half a million tonnes of wild fish are caught in African waters and sent to Europe to feed animals, when they could have fed 33 million Africans instead. That number of people is more than the combined populations of Senegal, Mauritania, and The Gambia. Globally a fifth of wild fishes become fishmeal or fish oil, but 90 per cent of fishmeal fishes are suitable for human consumption.

China uses nearly half of all FMFO, but then China uses most of everything. Europe also takes and takes. Spain imports the most fish oil from Senegal, and France takes 70 per cent of Mauritania's.

In 2019, Changing Markets Foundation produced a detailed investigative report into the fishmeal industry in India, Vietnam, and The Gambia. In each country, the pattern was similar: first the foreign factories come, then they take the fish, then they pollute the environment, then the fishermen say there are no fish left.

Although noting 'a surprising lack of traceability and transparency regarding the origin and supply chain of farmed seafood products,' the foundation linked plenty of reputable European retailers to FMFO supply chains that may use West African fish. For example: Sainsbury's, ALDI, Lidl, and Marks & Spencer in the UK; Auchan, Groupe Casino, Monoprix, and Système U in France (that is a full house of big French supermarkets); all the German ALDIs; and Mercadona in Spain. Sainsbury's, Marks & Spencer, and Mercadona have said they don't use West African FMFO in their seafood products, but how will they know?

The European Union's IUU [Illegal, Unreported and Unregulated fishing] regulations, which require a catch certificate or similar to show the fish was legally caught, do not cover fishmeal. In Mauritania, some Chinese-owned fishmeal factories have their own trawler fleets. The fish bypasses human mouths and goes straight to the factory. That is one tactic. The other is to outbid.

The fish processors tell me that they cannot compete with the prices that fish factories will pay for sardinella. Fish processors get no subsidies from the government, unlike Chinese fishing companies. In The Gambia, one fishmeal factory used 40 per cent of the country's entire fish catch in one year. Black and white. White stealing from Black. The villain/victim template seems neat and unassailable.

It is true — Europeans are using fish that West Africans could eat — and yet it is not all the truth. In Senegal, The Gambia, Mauritania, local fishermen supply fishmeal factories because the factories pay better. In Senegal, a fisheries union official tells me that there are too many pirogues. They are chasing smaller and smaller fish to sell to the factories. It is unsustainable.

The website of the IFFO, which used to stand for International Fishmeal and Fish Oil Organization and now somehow is short for the Marine Ingredients Organisation, is plain. Marine ingredients 'play an essential role in global food security'.

Rubbish, said Francisco Marí of Bread for the World at the CAOPA [African Confederation of Professional Organisations of Artisanal Fisheries] workshop. 'It's just for prawns and salmon — they are not necessary foods; it's a luxury. It's not enough for us to have 10—15 per cent of fish to feed salmon and prawns. Indirectly, we are eating your fish. It's not essential for the alimentation of the US or Japan. We are taking your fish to feed a luxury product that we don't need.'

Every Last Fish: A Deep Dive into the World of Fishes and Fishing by Rose George is published by Granta

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Archaeologists digging in the medieval city of Great Zimbabwe have discovered pieces of jade-green Chinese pottery, suggesting that the enigmatic empire had long-distance connections with East Asia more than 1,000 years ago.

Great Zimbabwe, located in the southeastern part of modern-day Zimbabwe, was the capital of an ancient empire that arose in southeastern Africa in around A.D. 1000. Little is known about this precolonial empire because its people did not leave a written history, but new archaeological excavations are shining a light on the enormous scale of the centuries-old civilization known for its intricate metalworking and ritual stone carvings.

In the new PBS documentary "Secrets of the Dead: Africa's Golden City," filmmakers followed a team of archaeologists from the field to the laboratory to try to answer questions surrounding the origins of the understudied civilization, its ritual and trade activities and why it disappeared after 500 years.

"When I was growing up, I was surrounded by symbols of Great Zimbabwe," University of Oxford archaeologist Shadreck Chirikure, who is leading the new excavations at the site, said in the documentary. "It was only when I started studying archaeology at university that I started realizing that there was this very big debate around who built Great Zimbabwe."

The site was first excavated in the late 19th century and quickly looted by British colonists for its ivory, metal and gold artifacts. These colonists insisted that Africans hadn't built Great Zimbabwe, instead claiming it arose from the Phoenicians, a people originally from the Mediterranean; they used that inaccuracy to justify taking all the artifacts to England, according to the documentary. Today, many Great Zimbabwean artifacts are held in the collection of the Pitt Rivers Museum at the University of Oxford.

But excavations are showing that Great Zimbabwe was a highly connected African kingdom that flourished from the 11th century until at least the 15th century, when the population may have gotten too large for the dry, over-farmed land to feed. Archaeologists have already discovered glass artifacts at Great Zimbabwe that came from Southeast Asia, India and the Middle East via boat.

"From India or Sri Lanka to Great Zimbabwe, it's at least 8,000 kilometers [5,000 miles]," Chirikure told Live Science. Merchants sailed the Indian Ocean using winds kicked up by monsoon cycles.

"It's time we try to understand a bit more about trade and exchange," Chirikure said, "particularly by comparing the communities in places like Sri Lanka and southern Africa. Because it's the water that separated people, but it was also the water that connected people."

In this exclusive clip from the documentary, Chirikure and archaeologist Muchen Zhou, a doctoral student at the University of Oxford, examine a jade-green piece of pottery unearthed from the hillside at Great Zimbabwe. The glossy sheen on the sherd suggests the pot was fired at an extremely high temperature, a technological achievement that had only been accomplished in China at that early date. This style of pottery, called Longquan celadon, was made in eastern China starting around A.D. 950.

"We find it across the site of Great Zimbabwe," Chirikure said, but in small quantities. "This means the Chinese ceramics are a rarity. Perhaps they were used by the elites. They would have been quite a significant or highly valued exotic ware."

Other evidence of long-distance trade has been discovered at Great Zimbabwe, Chirikure said, including metal objects from what is today the Democratic Republic of Congo, around 1,250 miles (2,000 kilometers) away. The people of Great Zimbabwe were also sourcing copper and tin from modern-day South Africa, more than 300 miles (500 km) away. And chemical analysis of cattle bones has shown that some of the animals were being traded across an 87-mile (140 km) area.

For his next project, Chirikure hopes to investigate local resources, such as soapstone, that hold a lot of meaning for the local Shona people, Zimbabwe's largest Indigenous group; and for Zimbabweans.

"Soapstone birds are an important part of Great Zimbabwe," he said, "but no one really knows where they got their soapstone from."

The Zimbabwe Bird, designed based on a series of birds carved from soapstone that were found at the archaeological site, is the national emblem and appears prominently on the country's flag.

"There are a number of soapstone outcrops around Great Zimbabwe," Chirikure said. "Next time in the field, that's one of the things I want to do — just go out there and try and find the geological sources of that soapstone."

The PBS documentary "Secrets of the Dead: Africa's Golden City" premieres Wednesday, Oct. 14, at 10 p.m. U.S. Eastern time.