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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'> 'We're not a competitor to fusion. We are fusion': Inside the race to harness unlimited solar power in space

"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.

'> Mysterious hole in Neanderthal shoulder blade may have been a 'kill shot' from a wooden spear, according to archaeologists

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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'> Testosterone for menopause: The treatment is rising in popularity, but does it work?

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.

'> Chronic back pain may activate an unexpected brain network, study finds 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."

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'> DNA from centuries-old skeletons buried in Montreal reveals no genetic mixing between Indigenous people and French colonists