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Features

- How to nurture the right mindset for living to 100 (paid): 2025 Sep 16

- The real scientific insights from Bryan Johnson’s immortality quest (paid): 2025 Sep 16

- What’s the secret to living well beyond the average life expectancy? (paid): 2025 Sep 16

- The science revealing how the right diet can add a decade to your life (paid): 2025 Sep 16

- The exercises you need to do to reach 100 in great shape (paid): 2025 Sep 16

- Why caring for your microbiome is crucial if you want to live to 100 (paid): 2025 Sep 16

- What it’s like to run the world’s best dark matter detector (paid): 2025 Sep 15

HEALTH | SEP 16, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

How to nurture the right mindset for living to 100

It’s not just diet and exercise that governs how well you age. Your mindset, social connections and sense of purpose make a big difference, and it’s never too late to start working on them

By Helen Thomson

Sam Peet

“I’m 87. I don’t feel 87, I don’t think like I’m 87,” declared Elaine Neuwirth on TikTok. “The most important thing is to get involved… interact with other people… have a purpose. Get up and move… Be part of the world.”

Her words, now viewed by 3.6 million people and counting, capture the growing scientific consensus that it isn’t enough to just eat well and exercise regularly: to live a long life, you must nurture your psychological well-being, too. And while you can’t outrun a lifetime of poor dietary choices and a sedentary lifestyle, there is evidence to suggest it is never too late to reap the benefits of making some psychological tweaks.

This article is part of a special issue in which we explore how to make your latter years as healthy and happy as possible. Read more here

Let’s start with your relationships. To understand their importance, turn to the longest in-depth study of human life ever performed, the Harvard Study of Adult Development. Since 1938, it has followed 724 boys and young men, and more than 1300 of their descendants, to identify what makes people flourish, both physically and mentally.

Mark Schultz, associate director of the study, says one thing stands out: high-quality relationships. It turns out that social ties are powerful predictors of late-life health and well-being. For instance, one analysis of data from the study showed that men who have more positive social relationships and are more involved with their community during midlife have a lower risk of depression and better cognition in late life.

“People we’re close to help us figure out solutions to problems; they help us regulate difficult emotions,” says Schultz. “Just being near people calms the body in important ways.” This is because close relationships positively affect our hormones, our immune systems and even how our genes are expressed.

Immune system impact

When people are in good relationships, their wounds literally heal quicker. Several studies published over the past year hint at why. They show, for instance, that having more close friends is associated with a stronger immune system in general and a greater proportion of cells that delay immune ageing – suggesting that sociability can help make the immune system more potent and youthful.

Having close friendships also appears to alter the activity of genes responsible for cellular ageing and several of the systems that help our bodies cope with stress. And since chronic stress is a known driver of heart disease, Alzheimer’s and many other conditions, these effects can be significant over the long run. For instance, one analysis of 148 different studies of links between social connectivity and longevity found a 50 per cent increased likelihood of survival for participants with stronger social relationships.

But how many relationships are enough? “If you have no one who’s got your back, then going from zero to one will obviously bring huge gains,” says Schultz, “but the literature is pretty consistent that larger networks are associated with better health.”

The social network

A useful test, he says, is to ask yourself who you would call if you woke up sick or scared at night. If no one comes to mind, you may be at risk of loneliness, a driver for depression, heart disease and cognitive decline. Loneliness is so bad for our health that its influence on early death is greater than that of obesity.

“The emotional pain resulting from loneliness can produce the same stress response as a chronic medical condition and thus lead to chronic inflammation and reduced immunity,” says Ashwini Nadkarni at Harvard Medical School. “This is why enhancing a sense of community can be so important while ageing.”

Positive social relationships and a sense of purpose have an impact on how long we live

Cavan Images/Alamy

The good news is that tackling loneliness doesn’t require professional help. Clinical psychologist Katherine Schafer at Vanderbilt University Medical Center in Tennessee recommends two steps: find a way to contribute to someone else’s life and let others contribute to yours. “Start super small. Did you see a new parent drop a toddler’s shoe? Grab the shoe and hand it to the parent. You have positively impacted someone,” she says. “Letting people do the same for you, and considering the way they cared, can have a great impact and lead to connections – the antidote to loneliness.”

“ Purpose – something that gives your life direction or makes it feel meaningful – can keep you alive for longer “

Alongside tending to your social connections, you might also want to consider your sense of purpose. Yes, it may whiff of unscientific woo, but there’s growing consensus that purpose – something that gives your life direction or makes it feel meaningful – can keep you alive for longer.

Having purpose is associated with a reduced risk of chronic disease and overall mortality. The mechanisms haven’t been elucidated just yet, but having purpose is thought to lower stress levels and motivate people to exhibit healthier behaviours. If it doesn’t come naturally, though, can finding purpose later in life make a difference?

In 2022, Eric Kim at the University of British Columbia in Canada and his colleagues set out to answer that by analysing data from nearly 13,000 US adults over 50. Participants had their sense of purpose and health measured across eight years. Those who found more purpose in life over that time had higher physical activity, fewer sleep problems and reduced risk of stroke and overall mortality.

Good attitude

It can also help to try to fight back against any negative attitudes you have about ageing itself. A 2022 study of almost 14,000 US adults over the age of 50 found that those who felt most positive about ageing had a 43 per cent lower risk of dying of any cause over four years compared with those who felt the least positive.

Other studies have shown the influence of mindset on health: shifting away from negative thoughts can reduce chronic stress, while becoming optimistic can decrease your risk of heart disease.

Stacking the odds in favour of a long and healthy life was always going to require effort. So, alongside diet and exercise, remember to nurture your psychological well-being. Call a friend, embrace ageing and reflect on what is truly valuable. As Neuwirth says, get up and be part of the world. It might just help you stay in it for longer.

HEALTH | SEP 16, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

The real scientific insights from Bryan Johnson’s immortality quest

Tech millionaire turned longevity pioneer Bryan Johnson devotes more than 6 hours a day to trialling different methods to turn back the clock. Can the rest of us learn anything from his radical approach?

By Claudia Canavan

Bryan Johnson devotes more than 6 hours a day to slow down or even reverse the ageing of his body

Agaton Strom/Redux/eyevine

Bryan Johnson is finishing his 6.5-hour morning routine when I sign on to Zoom for my allotted 15-minute call with him (a constraint of what a member of his team describes as his “crazy” schedule).

The tech millionaire turned longevity pioneer is standing in front of a cement wall in his California home, the coldness of which is relieved by green bursts of tropical houseplants. Wearing a helmet-like headset, a few wires trailing out and down past the screen, together with a black T-shirt bearing the words “Don’t Die”, the effect is somewhere between a luxury Balinese villa and a VR store designed by Apple.

This article is part of a special issue in which we explore how to make your latter years as healthy and happy as possible. Read more here

Immortality has been a human preoccupation for millennia, but it is hard to imagine anyone going to greater lengths to reach for it than Johnson. Take his headset. That’s an experiment to improve cognitive function by stimulating certain brain regions with infrared light. He has been using it for 10 minutes a day for the past two weeks “to see if the treatments have measurable effects on my cognition”, he says.

The other 6 hours and 20 minutes that Johnson devotes daily to longevity work are spent, variously, measuring his waking body temperature, using serums for hair growth, working out for an hour – cardio, strength, balance – taking a 20-minute sauna, using red light therapy and hypoxia therapy (the latter is a new addition, involving breathing in varying concentrations of oxygen) before eating breakfast. This is a mix of ground nuts, seeds and blueberries, extra virgin olive oil, pomegranate juice extract, cocoa, collagen protein, pea and hemp protein, cinnamon powder, Omega-3, Omega-6, grapeseed extract and macadamia nut milk, among other ingredients. All this is to “follow the data and the science” to turn back the clock.

“A lot of people hear this and they think, ‘That’s crazy’,” he says. “The way they can think about it is I’m a professional rejuvenation athlete. I’m like an Olympian, but for longevity.”

Sam Peet

Johnson, now 48, began his longevity quest after a series of midlife endings: leaving the Mormon church he was raised in; ending his marriage; and selling his mobile payment company. This sale is how he made the millions that fund his endeavours.

Project Blueprint

In 2021, he announced the start of Project Blueprint, a mission to measure his organs and try to “maximally” reverse the biological age of each. (He also runs a start-up named Blueprint, selling supplements, blood tests and other products, which is the subject of multiple controversies.) Johnson claims that his bone mineral density is in the top 0.2 per cent of all people, his cardiovascular fitness is better than 85 per cent of 20-year-olds and he has the fertility health of a 20-year-old, too.

Going to extreme, and often unevidenced, lengths in the pursuit of a longer life isn’t atypical for his tech millionaire cohort. But with a strict routine that entails having his last meal at 11am, Johnson is surely the most extreme player in the longevity game, and he has amassed a team of 30 different specialists to assist with the quest. “We try to find people in every domain of expertise… the brain, the heart, protein patterns,” he says. “This project really speaks to them because we’re very playful, we’re very experimental.”

Rapamycin trials

“Very experimental” is a fair assessment. Johnson’s protocols sometimes involve taking drugs based on limited trials in humans, like rapamycin, a drug originally formulated to act as an immunosuppressant for people after an organ transplant, and which is being investigated for possible anti-ageing effects. Promising results have been seen in mouse studies, but Johnson stopped taking the drug last year after experiencing side effects. His team then also found a study indicating that rapamycin may accelerate ageing in humans.

So, is he ever fearful of experimenting with interventions that aren’t backed up by solid science?

“I would flip that. A lot of people would look at this experiment and say, ‘Bryan, but wait, you are at so much risk!’ and I say, ‘Friend, you are at greater risk than I am because you are experimenting with fast food and staying up late and drinking alcohol and eating toxins’,” says Johnson. “Their lives are higher-risk than mine. I am taking fewer risks overall because I eat well, I sleep well and I exercise all the time. I look at them and say, ’Why are you running the experiment to see what happens to you when you eat junk food?’”

If some scientists enjoy Johnson’s experiment, others question the semantics used. Richard Siow, director of ageing research at King’s College London, notes that certain “biomarkers” associated with ageing are reversible. Things like indicators of inflammation found in blood, lung capacity, lipid levels, cholesterol and epigenetics are all modifiable, he says. But that doesn’t mean that attributing “ages” to them — for example, that someone has the metabolism of a 25-year-old at 40 — is possible. This is because we don’t have population-wide datasets drilling into the average biomarkers of people at specific ages. Longevity clinics offering such tests are likely to be basing these on limited datasets, says Siow. “The numbers are good for marketing, but clinically less meaningful.”

Unsurprisingly, Johnson’s research team disagrees. “Bryan Johnson knows the biological age of his organs through extensive, scientific testing and monitoring… using a variety of methods including MRI scans, ultrasounds, blood work, genetic screening (such as epigenetic clocks), and other clinical tests,” wrote one of them in an email. These metrics are shared via X, though they have yet to be analysed in peer-reviewed studies.

Still, Siow is glad that Johnson is willing to self-experiment in a way that couldn’t happen in a clinical trial, due to ethical issues, even though it isn’t possible to extrapolate from one person’s data to provide broad results that are applicable to the wider population, he says.

Top tip for living to 100

But for all his high-tech experimentation, Johnson’s top recommendation for everyone aiming to live to 100 is pretty straightforward: “Lower your resting heart rate before bed,” he says. “[This] determines how well you’re going to sleep. And how well you sleep determines if you will exercise, and if you exercise, that determines if you will eat well. So [it starts] a positive cascade.”

To lower your resting heart rate, he recommends stopping eating 4 hours before bed; taking an hour to wind down before sleep by reading, having a walk or meditating, and avoiding screens; and being mindful of heart rate-raising stimulants like caffeine. “And the biggest one is rumination. Rumination can increase heart rate between five and 25 beats per minute [by thinking about] things you’re mad about, worried about, obsessed about.”

Johnson takes his own advice to the nth degree. Surprisingly, though, the number of years he has left on the clock is less of a preoccupation than his efforts suggest.

When I ask him how long he expects to live, based on his current biomarkers, he is solemn. “I don’t think my life expectancy matters,” he says, due to advances in artificial intelligence. Part of his “Don’t Die” endeavour is to upload his thoughts to an AI model, meaning that he can exist in some form for an unquantifiable amount of time. “Right now is the first time we are seeing actual immortality being born, where you can in fact train a model on a human… The changes we’re going to see with AI will be so dramatic and will happen much faster than my expected 40-to-50-year time span that I have left, that it’s really not a relevant question.”

HEALTH | SEP 16, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

What’s the secret to living well beyond the average life expectancy?

Many of us know people who live into their 90s, but hardly anyone makes it to 100. Studies are now revealing that factors that really make a difference

By Graham Lawton

Sam Peet

My parents are both in their 80s and are fit and well for people of their age. I would like them to be around for many years longer. So, what is the secret to getting from your 80s to 100 and beyond?

Good fortune plays a big part: avoiding fatal accidents or deadly infectious diseases and living in a peaceful country with clean water and a good healthcare system. It also helps if you win the genetic lottery. Women are much more likely than men to notch up a century: more than three-quarters of centenarians are female, and the list of the oldest-ever humans is utterly dominated by women.

Longevity also runs in families, and geneticists have identified hundreds of gene variants associated with living to a ripe old age. Research on twins and family trees suggests that the biological traits associated with extreme longevity are about 30 per cent heritable. Most of these genes appear to confer unusual levels of protection against the diseases of old age, such as cardiovascular disease, according to Nir Barzilai, who studies “superagers” at the Albert Einstein College of Medicine in New York City.

This article is part of a special issue in which we explore how to make your latter years as healthy and happy as possible. Read more here

Longevity genes

The best way to tell if you have got a longevity-promoting genome is to look at your parents, if this is possible. There isn’t a whole lot you can do about your DNA, but the good news is that there is still plenty of scope to actively intervene. That might suggest a life of virtuous restraint – good diet, lots of exercise and sobriety. Surprisingly, however, these don’t appear to make much difference, at least in people who have already attained exceptional longevity.

A 2011 study dug into the lifestyles of 477 Ashkenazi Jews who had made it to 95 and were still living independently. Three-quarters of them were women; the oldest was 109. The researchers collected data on their diet, physical activity, smoking, alcohol consumption and body mass index, and compared this to a representative sample of the general population born at the same time, most of whom had already died. There were no significant differences. The survivors were just as likely as their deceased peers to have drunk alcohol regularly, had similar BMIs and done similar amounts of exercise.

But don’t read too much into that, warns Barzilai. Among these very old people will be a disproportionately large number of the lucky few who inherited a great set of longevity genes and can withstand all sorts of insults that would do the rest of us in.

Paraguayan centenarian Anacleto Escobar on his 100th birthday, together with his wife.

AFP via Getty Images

For mere mortals, a healthy lifestyle is absolutely crucial to keeping going after 80. “There are four things,” says Barzilai. “Optimise your exercise, your sleep, your diet and your social connectivity.” Strength and flexibility exercises become increasingly important in older age, and 8 hours sleep is a good target. Eating a Mediterranean-style diet plus intermittent fasting, such as the 16:8 diet, is also very effective, he says.

Cognitive factors

How we look after our cognition also matters. This is the finding of a 2024 study of the life-course pathways that lead to exceptional longevity, which followed 547 people from the Lothian Birth Cohort study for 24 years after they reached the age of 79. The research revealed that cognitive ability in later life was an important predictor of survival in the oldest participants, having more impact on longevity than their physical functioning.

This highlights the importance of making our brain “fitter” throughout our lives by building new brain connections or “cognitive reserve”. However, the Lothian study found that three early life factors – childhood social class, IQ at age 11 and length of time spent in education – were key contributors to higher cognitive function aged 79.

“ Social connectivity is perhaps the surprise ingredient “

Social connectivity is perhaps the surprise ingredient. A few years ago, Boo Johansson and Valgeir Thorvaldsson at the University of Gothenburg in Sweden dug into data collected on 699 octogenarian, nonagenarian and centenarian Swedes who had subsequently died to see what distinguished those who made it only to their early 80s from those who kept going through into their late 80s and beyond. Predictably, they found that a healthy lifestyle increases the likelihood of living longer. But social factors also scored very highly. “Perhaps the most striking finding, at least for the general public, was the relative importance of what might be called ‘softer’ factors,” says Thorvaldsson. “Higher life satisfaction and stronger social connections.”

People over 80 who had people to talk to and felt part of a friendship group survived longer than those who lacked company or felt abandoned. The closer and more emotionally rewarding those connections, the better.

Life satisfaction also had a major impact. This was measured by the responses to 13 statements such as “As I grow older, things seem better than I thought they would be” and “When I think back over my life, I didn’t get most of the important things I wanted.”

Other researchers have also found that low life satisfaction is a major risk factor for earlier death among men in their 80s. “We were not surprised to find an association between life satisfaction and mortality, but we were quite surprised by the magnitude of the effect,” says lead researcher Phil St John at the University of Manitoba in Winnipeg, Canada.

Anti-ageing drugs

Good social connectedness and life satisfaction aren’t always easy to engineer, but there is another route to healthier ageing, says Barzilai. “There are four drugs that can be repurposed to treat ageing,” he says. These are the diabetes drugs metformin and the SGLT2 inhibitors, GLP-1 agonists like the weight-loss or diabetes drugs Ozempic and Wegovy, and the osteoporosis drug zoledronic acid.

These medicines were developed for specific conditions, but they also happen to target the biology of ageing in general. “All the evidence is that you take them at an old age and prevent a variety of diseases and also overall mortality,” says Barzilai – though whether your doctor will prescribe them to “treat” ageing is a different matter.

HEALTH | SEP 16, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

The science revealing how the right diet can add a decade to your life

Evidence shows that eating a longevity diet can dramatically lengthen your lifespan – and the sooner you start, the more of a difference it makes

By Graham Lawton

Sam Peet

One of the standard questions put to centenarians is: “What’s your secret?” The answers often revolve around food. For Maria Branyas Morera, who was the world’s oldest person when she died last year aged 117, it was eating three yogurts a day. Jeanne Calment, officially the oldest person to have ever lived (though that has been disputed), put her amazing staying power down to olive oil, chocolate and the occasional glass of port.

Of course, what you eat matters. Diet has a huge influence on your health, and staying healthy is a prerequisite for a long life. But a better question might be: “What didn’t you eat?”

This article is part of a special issue in which we explore how to make your latter years as healthy and happy as possible. Read more here

For instance, Lars Fadnes at the University of Bergen in Norway and his colleagues have recently devised a longevity-enhancing diet, based on their analysis of a huge dataset called the Global Burden of Disease Study. This revealed, to no great surprise, that typical Western diets – high in refined grains, added sugars, red and processed meats and dairy products, and low in wholegrains, fresh fruit and vegetables, nuts and fish – aren’t optimal for longevity. In fact, they are deadly, responsible for 11 million premature deaths a year.

The researchers modelled what would happen if people eating this diet switched permanently to a healthier one, and found a major impact on life expectancy. For example, a 20-year-old woman in the US today can expect to live to 80 on a typical diet eaten there. But if she drastically cut down on meat, sugar, dairy and refined grains and switched permanently to a diet of mostly wholegrains, fruit, vegetables, nuts, legumes and fish, her life expectancy would increase to 89 – a gain of nearly a decade. A 20-year-old US man making the same switch would similarly increase his life expectancy, albeit from a lower starting point, from 76 to 86.

“We gain a lot from increasing whole grains, nuts and legumes, and also reducing sugary foods and meats, processed and red meats in particular,” says Fadnes.

“ Even if your 20th birthday is a long time ago, there are good reasons to still make the change “

And even if your 20th birthday is a long time ago, there are good reasons to still make the change. A 60-year-old US woman making the switch would gain more than seven extra years, increasing her life expectancy from 81.6 to 89. Even an 80-year-old gains a few extra years.

Fadnes also modelled what would happen if people switched to a diet halfway between a Western-style one and the optimal one. They still saw gains in life expectancy, albeit lesser ones.

Eating plenty of fresh vegetables can add years to your life

nrd/Unsplash

These are theoretical models – a clinical trial of a longevity-promoting diet would take decades to deliver results. But there is real-world data to back the headline conclusion that diet has a big impact on health in later life.

Last year, Zhaoli Dai-Keller at the University of New South Wales in Sydney, Australia, and her colleagues took a deep dive into the dietary habits of thousands of people aged 95 and over who still lived in community settings across east Asia, Australia and western Europe. By definition, these people had aged successfully, and the researchers found that they had earned it.

Don’t add salt

They were, on the whole, paragons of dietary virtue. Only a quarter drank alcohol, and they mostly ate a balanced and diverse diet rich in fruit, vegetables, white meat, fish and legumes. Something else also stood out, says Dai-Keller. “Salt intake tends to be lower in the centenarians,” she says. High salt consumption is a causal factor in cardiovascular disease, the world’s biggest killer.

In a similar study, Anne-Julie Tessier and Marta Guasch-Ferré at Harvard T.H. Chan School of Public Health in Boston, Massachusetts, and their colleagues reanalysed data from two research projects that followed more than 105,000 people over three decades starting in 1986, as they progressed from middle age into early old age. They were looking for evidence of healthy ageing, which they defined as reaching 70 free from major chronic diseases, as well as being physically fit and mentally sharp.

Only around 10 per cent of the participants achieved that, and when the researchers analysed what they had in common, they found that diet was key. The majority had stuck to healthy Mediterranean-style fare throughout middle age. Those who binged on fatty, salty and meaty foods, on the other hand, rarely aged healthily.

Reaching 70 in good health is no guarantee of getting to 100, of course, but it helps.

However, longevity isn’t just about what you eat, but how much. According to the 2024 study led by Dai-Keller, one of the defining features of people aged 95 and over is that they are slim. Around half were a normal weight, and a third were underweight.

Weight and day-to-day functioning

Obesity isn’t a prescription for making it to 100, it seems. However, when the researchers looked at the ability of their participants to carry out basic daily living activities, they found that being overweight, but not obese, was significantly helpful for day-to-day functioning compared with being a normal weight. Being underweight increased the risk of impairment by around 25 per cent.

Which brings us neatly to one of the methods sometimes advocated for longevity: calorie restriction. One of the most reliable ways to extend the lifespans of laboratory animals is to restrict their preferred calorie intake by 25 per cent or more. However, it is hard for people to do this, and calorie restriction has yet to be proven to work in humans – and even if it does extend life, it might impair the ability to carry out day-to-day tasks.

All in all, though, if you want to give yourself the best chance of living to 100 in the best condition possible, a large slice of the secret is on your plate.

HEALTH | SEP 16, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

The exercises you need to do to reach 100 in great shape

To be truly fit in older age, you need to work on specific aspects of your fitness – and research shows that it’s never too late to reap the benefits

By Caroline Williams

Sam Peet

“My secret is that I never get off the sofa,” said no centenarian, ever. But it is worth noting that the world’s oldest people rarely mention punishing fitness regimes, either. Instead, centenarians tend to report a lifetime of regular, moderate exercise, such as walking, farming and gardening.

This exact prescription doesn’t fit well into many modern lifestyles, but that hasn’t stopped scientists from trying to identify the optimal dose and type of exercise for a long, healthy life.

This article is part of a special issue in which we explore how to make your latter years as healthy and happy as possible. Read more here

What is clear is that doing nothing isn’t an option. Lack of physical activity has been linked to at least 3.9 million premature deaths globally per year, and it significantly increases the risk of chronic illnesses, including heart disease, stroke and some cancers. On the flip side, getting enough exercise can add up to seven years to your life, while also extending the time you spend in good health.

The evolution of exercise

A rough guide to how much is enough can be found in our evolutionary history. Modern hunter-gatherers, the closest we can get to how our ancestors lived, take around 11,000 to 20,000 steps per day, and get their resistance training from hunting, climbing, digging for tubers and carrying the resources they collect home.

They have lower rates of chronic diseases seen in Western nations, and the reason seems to lie in the body’s response to all this work, which results in a surge in internal maintenance and repair. Harvard University evolutionary anthropologist Daniel Lieberman speculates that the reason exercise and physiological upkeep are linked is that evolution tied the two together, so that the genes involved in body repair and maintenance are activated only when we move. If we don’t, the body saves energy by letting these functions slide.

Because of the “use it or lose it” aspect of this, a growing number of researchers see exercise not as an “anti-ageing” strategy, but as a way to reverse the life-shortening and illness-inducing effects of a chronic lack of movement, potentially adding healthy years to our lives. “Exercise is one of those strategies that we can adopt in order to optimise the rate at which we decline,” says Norman Lazarus, emeritus professor of exercise physiology at King’s College London.

How much?

So how much will do the trick? Lazarus says that the World Health Organization’s (WHO) guidelines are a good place to start. Based on large epidemiological studies, these state that adults should do at least 150 to 300 minutes per week of moderate-intensity physical activity (exercise that leaves you able to talk, but not sing, such as brisk walking), or 75 to 150 minutes at vigorous intensity (running, or cycling in hilly terrain, which leaves you breathing hard and fast), plus strength training done at least two days per week. People aged 65 or over should do an extra strength session and add balance and mobility exercises.

Importantly, none of this has to be in the form of structured exercise. Anything that uses physical strength or raises the heart rate will do the job (see “Longevity hacks” for one suggestion, plus some other lesser-known things you can try). And it doesn’t all have to come in one session – there is some evidence that multiple workouts are just as effective as longer, more structured ones.

“ From middle age onwards everyone should get serious about working on their muscle strength “

Mikel Izquierdo at the Public University of Navarra in Spain and lead author on a “global consensus” on exercise recommendations for healthy longevity, which was published in January, agrees that the WHO guidelines are a good guide to lowering disease risk and extending lifespan. But, he adds, they may not be enough to guarantee a sprightly old age. “The majority of studies supporting the WHO recommendations focus on reducing disease risk and mortality, rather than functional independence,” he says. “The reality is that meeting the basic guidelines doesn’t automatically translate into preserved autonomy, especially in populations over 65.”

Give me strength

From middle age onwards, says Izquierdo, everyone should get serious about working on their muscle strength. From our 30s on, muscle mass starts to decline, with fast-twitch muscle fibres, those needed to stand up from a chair, for example, taking the biggest hit. If left unchecked, this loss of strength and endurance can lead to problems with walking, standing and an increased risk of falls and dying of any cause for older people.

Exercises to work on strength, balance and mobility are particuarly important for people over the age of 65

Andrii Iemelianenko/Alamy

Multiple studies, for instance, have shown a link between weaker hand grip strength and a shorter lifespan. However, this doesn’t mean you necessarily need to beef up your hands. Grip strength is a proxy for overall muscle strength because it is easy to measure and has been shown to correlate with strength in the major muscle groups, particularly the legs.

The balancing act

It is also a good idea to work on balance from middle age onwards. According to a 2022 study, people aged 51 to 75 who couldn’t balance on one leg for 10 seconds were twice as likely to die within the following 10 years.

Bodyweight exercises such as squats and planks are a good place to start, says Izquierdo, but as muscle loss accelerates, the only way to stay one step ahead of this decline is to gradually increase the load by adding weights or using resistance bands.

Maria Fiatarone Singh, a geriatrician at the University of Sydney, also advises power training: jumping up stairs for those who are more agile, or doing fast leg presses in the gym at 80 per cent of the maximum weight a person can lift. This is because more explosive strength training builds up fast-twitch “type II” muscle fibres, which are the first to be lost during ageing.

It is never too late to start. Power and strength training have helped even frail people in their 90s build muscle, which in turn improved their ability to stand and walk independently. Intriguingly, even the intention to get stronger has some benefit, says Fiatarone Singh. Even if the weight doesn’t move much at first, “it is the ‘intent’ to move fast which sends the message from the brain to the type II fibres to contract which optimally recruits them”, she says.

There are health benefits even if you only start exercising in older age

Panther Media Global/Alamy

So, all in all, there are many ways that we can fight against the physical decline of ageing. But we should also be realistic, says Lazarus, a keen cyclist who is approaching his 90th birthday.

There is only so much that exercise – or any other intervention – can do. “There are things happening to us over which we’ve got no control,” says Lazarus. Maximal heart rate, for example – an estimate of the fastest rate that should be possible during exercise – is 220 minus age. “The formula doesn’t say 220 minus age plus exercise, it says 220 minus time passing,” says Lazarus. “You can exercise until the cows come home, you’re not going to change that.” Even elite athletes lose muscle mass, strength and cardiovascular efficiency with age, no matter how much they train.

“We are all going to die,” says Lazarus. “You want to keep functioning as long as possible and die in a year. Not slowly over 40 or 50 years.”

Or, as Izquierdo puts it, we should aim to “die young, as late as possible”.

Longevity hacks

Here are five simple but lesser-known things you can do now for a healthier older age.

Sit on the floor

Sitting on the ground isn’t just for children. Getting up and down from the floor strengthens leg and core muscles and keeps joints flexible. What’s more, the ability to do this as an adult is linked to a significantly longer life. If possible, try getting up without using your hands for an extra challenge.

Floss your teeth

Let your oral hygiene slip, and harmful microbes from your mouth can travel all over the body, triggering problems – from cardiovascular disease and cancer to Alzheimer’s disease and arthritis. Keeping your oral microbiome in balance, however, staves off decline.

Train your nose

A declining ability to detect aromas is linked to conditions such as Parkinson’s and Alzheimer’s. Restoring this neglected sense might not only reduce cognitive decline, but studies also show it could reverse it – and the ability to smell is something that can be trained.

Have sex

“A fulfilling sex life is an essential part of subjective well-being” was the conclusion of one review of research into the link between the sex lives of people aged 40 to 90-plus and how positively they felt about themselves.

Mix with younger people

Aside from any psychological benefits, your microbiome will get a boost from mixing with younger people. Our gut microbiomes are shaped by those of the people around us, and a shift to a more youthful profile is linked to better health.

HEALTH | SEP 16, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

Why caring for your microbiome is crucial if you want to live to 100

Our friendly – and not so friendly – gut bacteria lie at the core of healthy ageing. Research is now revealing what it takes to maintain a youthful microbiome

By Helen Thomson

Sam Peet

If you want to live to a grand old age, it might help to think of yourself not as a human, but rather a holobiont – a collective of human cells plus the trillions of microbes that live in and on you.

Because it isn’t just our own cells that change with age; our microbiome transforms too. And, increasingly, researchers are showing that our friendly – and not so friendly – bacteria and other residents lie at the core of healthy ageing. Nurturing them may be a smart way to live healthier and longer.

This article is part of a special issue in which we explore how to make your latter years as healthy and happy as possible. Read more here

More than a century ago, zoologist Élie Metchnikoff speculated that senility was caused by “putrefactive bacterial autotoxins” and recommended fermented milk and a simple lifestyle as a remedy. Today, that early theory has blossomed. We now know that our microbiome is so deeply embedded in our physiology that it influences everything from digestion to metabolism and even brain function.

Yet untangling its impact has been challenging. “The complexity of the microbiome is akin to the complexity of the human brain,” says microbiologist Filipe Cabreiro at Imperial College London.

No two people’s microbiomes are the same, and even within an individual, it can shift from day to day. But we are gaining some vital clues. We are getting a much better idea, for instance, about which gut residents are beneficial and which are pathogenic. One thing has become clear: diversity is key. The greater the variety of gut microbes, the healthier you tend to be.

“ Gut microbiota signatures of centenarians show similarity to those of young people “

Unfortunately, as we age, our microbiome changes, tending to show a decreased abundance of healthy bacteria in later life. Older adults tend to eat less diverse diets, take more medication and have fewer social interactions – all of which have knock-on effects on the types of microbes living in the gut. But even animals raised in identical conditions throughout life show age-related changes in their microbiome, suggesting an intrinsic shift with age.

To understand the impact of this decline, many researchers have focused on microbes that produce short-chain fatty acids (SCFA) through the fermentation of dietary fibres. SCFAs are involved in many beneficial processes, such as maintaining the cells in our gut lining, suppressing inflammation, regulating our immune system’s response to pathogens and controlling blood sugar levels.

Inflammaging

As we age, the number of microbes making SCFAs reduces while the pro-inflammatory ones increase. “This imbalance is thought to contribute to chronic, low-grade inflammation, a state known as inflammaging, which is associated with higher risk of conditions such as cardiovascular disease, dementia and stroke,” says Jessica Schneider, chief scientific officer at Corundum Systems Biology, a company in Tokyo, Japan, that invests in research.

However, the gut microbiomes of people who reach extreme old age seem to be better able to resist this decline. Key evidence of this comes from a 2023 study of 1575 people aged between 20 and 117 by Shifu Pang and Xiaodong Chen of Guangxi Medical University in Nanning, China, and their colleagues. The study found that, compared with adults aged 66 to 85, the gut microbial signature of those aged 100 to 117 was more similar to that of young people, with higher diversity and greater abundance of beneficial bacteria from the Bacteroides phylum. “Our results strongly suggest that the gut microbiota signatures of centenarians show similarity to those of young people,” the researchers concluded, and speculate that this factor contributes to longevity.

This raises the question of whether we can nurture our microbiome to age better.

Changing your gut microbes isn’t easy. “You’re trying to introduce a complex community into another complex community that tends to be strong,” says Cabreiro. Nevertheless, while prebiotics, supplements which provide food for helpful gut microbes, and probiotics, gut-friendly microbes that you can take as a supplement, may not fundamentally reshape the microbiome, they might give it a nudge in the right direction, at least temporarily.

A healthy plant-based diet, including plenty of legumes, helps nurture the gut microbiome

Betty Subrizi/Unsplash

For instance, last year, nutrition company Zoe showed in a randomised trial that its prebiotic, with 30 plant-based nutrients, increased beneficial bacteria, with some improvements in health measures such as inflammatory compounds in blood.

Another study, of 50 adults living in nursing homes, showed that taking a daily prebiotic containing the plant-derived compounds fructooligosaccharides and inulin over 13 weeks improved measures of frailty compared with a placebo.

Dietary changes may be just as effective. When older adults across several countries adopted a Mediterranean diet for one year, those who adhered most closely retained more microbial diversity and boosted gut microbes linked with healthy ageing. This correlated with many improvements to their health, says Schneider, such as better walking speed, strength and memory.

More radical treatments are also being explored. Faecal microbiota transplants have already been approved for Clostridium difficile infections, and promising data shows they could also treat other conditions, but whether such approaches can extend lifespan remains an open question. In animals, swapping out an old microbiome for a younger, healthier one has striking results – older killifish live 37 per cent longer if they have eaten the faeces from younger fish, for instance. Mouse experiments show similar gains.

But the field is still in its infancy, says Cabreiro. We have much to learn. Microbial activity affects many biological pathways associated with ageing, including those in mitochondria, metabolism and the immune system, and we are only just beginning to explore how we might manipulate our microbes, through diet, drugs or even CRISPR gene-editing technologies.

“It’s early days, we haven’t figured it all out properly,” says Cabreiro, “But there’s excitement about how this can all benefit our health and longevity – and rightly so.”

PHYSICS | SEP 15, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

What it’s like to run the world’s best dark matter detector

Chamkaur Ghag is on a mission to find the 85 per cent of the universe’s matter that we haven’t yet identified. He details his hopes for the major scientific experiment – and what the future could hold

By Leah Crane

Chamkaur Ghag is one of the leaders of the LUX-ZEPLIN experiment, a peerlessly sensitive dark matter detector

Nova

Deep underground in the middle of South Dakota, the most sensitive dark matter detector on Earth sits quietly waiting. This is the LUX-ZEPLIN (LZ) experiment, the central part of which is a large tank of liquid xenon. Physicist Chamkaur Ghag at University College London is one of the leaders of the huge scientific collaboration working on the experiment. Its mission is to find the 85 per cent of the universe’s matter that we haven’t yet identified.

Today, Ghag and his fellow hunters stand at something of a turning point in the search for this elusive substance. There are loose plans to build a detector called XLZD, which would be several times the size of LZ and even more sensitive. But if both of these fail to sniff out the goods, it will force physicists to reconsider what they think dark matter is made from. As Ghag says, that may mean the next generation of dark matter detectors won’t be underground behemoths, but surprisingly small and humble affairs. In fact, as he explains in advance of his upcoming talk at New Scientist Live this October, he has already built one such prototype.

Leah Crane: First things first, why is dark matter so important?

Chamkaur Ghag: On the one hand, we have particles and atoms and everything that particle physics tells us about how the constituents of matter come together. On the other hand, we have our understanding of gravity. It may seem like this is all good, but if you try to put gravity and particle physics together, there’s a big problem: our galaxy shouldn’t be here. It’s holding itself together with gravity that seems to come from matter that we can’t see. And it’s not just a little glue. Some 85 per cent of the matter in the universe is this so-called dark matter.

Why have we been hunting for it for so long and not found anything?

At the moment, we think dark matter is probably made of what we call WIMPs, or weakly interacting massive particles, which were born in the early universe. If so, it would only very rarely interact with other particles and even then give off an extremely feeble signature. So, we need huge detectors. The larger they are, the better the chance that a dark matter particle going through it will interact. And they have to be really quiet so they can be sensitive to the tiny recoils of particles hit by dark matter if it interacts – even the slightest vibration could mask the signal.

We talk about a theoretical phase space for dark matter, which means the range of possible masses and properties that this stuff could have. We have already ruled out some of this space. So we have to keep getting deeper underground, with larger and larger detectors, to approach the promised land: the theoretical phase space where particles of dark matter could still exist.

It is a ridiculously painstaking craft. With our detector, we had to make sure there was almost no background noise. For instance, most metals produce tiny amounts of radioactivity, so we had to work hard to minimise that problem in our construction materials. LZ is the lowest background noise, most radio-pure instrument on the planet.

SURF and the Black Hills, ancient and dark matter: South Dakota, US

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So LZ is the most sensitive detector that we have right now – how does it work?

Essentially, it’s a double-walled Thermos flask a few metres wide and a few metres tall that contains 7 tonnes of liquid xenon. In this flask, the xenon is in a highly reflective barrel, and it’s viewed from the top and bottom by light sensors. And then there’s a final touch: we have an electric field across this barrel. If a WIMP comes in and hits a xenon nucleus, it would produce a small flash of light, a few photons. But because we’ve got an electric field, we pull away the electrons [freed up in the collision] from the nucleus, and also produce a separate, brighter flash.

This means that anything that happens in our detector gives us two light signals. Where that happens tells us the position of the event, and then the amount of light from the primary flash versus the secondary flash tells us the microphysics of whether this was a WIMP that came in and hit the nucleus or something else, like say a gamma ray. We have it all a mile underground to shield from cosmic rays, and then we have it in a water tank to shield it from the rock itself.

It is such a complicated endeavour. What was the hardest part in getting it to work?

There was a similar, smaller predecessor experiment called LUX and we knew what we needed to do to get the instrument 10 times more sensitive. Actually doing it was challenging, if satisfying. For me, the hardest part was making sure the instrument was as clean and quiet as it needed to be. If you take LZ and you unfurl it, it’s huge, it’s a football pitch-sized area and we can only tolerate a single gram of dust on that whole surface.

What’s it like to work at that ultra-clean detector so far underground?

It’s a former gold mine, so there’s this very industrial-looking environment. You get your hard hats on and you go down a mile, and then there’s a bit of a trek to the lab. Once you’re into the lab, you can forget where you are. Then you’re into clean-room garb and it’s computers and equipment and whatnot –  it’s just a lab with no windows. But the journey down is sort of otherworldly.

The LUX-ZEPLIN experiment’s outer detector

Sanford Underground Research Facility/Matthew Kapust

Up to now, WIMPs have been the dominant candidate for dark matter. But with nobody spotting any evidence of them yet, at what point do we say WIMPs are dead?

I think if we reach the point where XLZD, the larger detector we have planned, has been built and has not seen them. If we are having to explore beyond the range of that instrument, it gets hard for the cookie-cutter standard WIMP to exist. But until that point, they’re still crazy alive. That territory between what we have explored so far and where XLZD will get, that’s the fun stuff.

You have developed a completely different and far smaller detector for dark matter. Tell us about that.

What we have is a 150-nanometre-wide glass bead that we levitate with lasers so that it acts as a highly sensitive force detector. What’s nice is that we can tell if it moves in any of the three dimensions. So, we can say, ‘OK, something has pinged it from a particular direction’. That’s great, because it means that now you can start to rule out all your terrestrial backgrounds, like radioactive decay from materials underground.

That’s quite a departure from the huge detectors like LZ. What’s the rationale behind building that – and will we see more small detectors?

The large underground experiments are huge, so they are super sensitive – but in a sense, the fact that they are so large actually limits their sensitivity. Let’s say that whenever a dark matter particle hits my xenon detector, it produces 10 photons. I can easily detect all of those if my xenon tank is small, but if I have a huge tank, they have to bounce around all over the place and I might only catch three of them.

Now, let’s imagine that any time a dark matter particle hits my detector, it only ever produces two photons in the first place. In that scenario, the maximal signal you can get from a detector akin to LZ diminishes. That’s why there is now a push to look for lower mass dark matter particles that are outside of the range of LZ – and that means turning to other sorts of detectors.

Let’s say we actually find dark matter. What does that mean for physics and the universe?

It solves two problems. This is the obvious one: what is this missing 85 per cent of the matter in our universe? But it would do that in a way that doesn’t involve the standard model of particle physics, our essential list of the building blocks of reality. So, if you find dark matter, you have your first peek outside this model. We have no solid evidence for anything specific outside of the standard model yet – nothing at all. This would be that first beam of light into the room.

News

- Wild chimpanzees may get mildly intoxicated from alcoholic fruit: 2025 Sep 17

- Dome-headed dinosaur from Mongolia is the oldest ever found: 2025 Sep 17

- Stretching the skin could enable vaccines to be given without a needle: 2025 Sep 17

- Global suicide rates fell 30 per cent since 1990 – but not in the US (paid): 2025 Sep 17

- Asteroid exploded 'similar to a bomb' over France in a rare event (paid): 2025 Sep 17

- 30,000-year-old toolkit shows what ancient hunter carried in a pouch (paid): 2025 Sep 16

- Long covid may be making your periods longer and heavier: 2025 Sep 16

- Around one-third of AI search tool answers make unsupported claims (paid): 2025 Sep 16

- Making atoms self-magnify reveals their quantum wave functions (paid): 2025 Sep 16

- Good immune health may come at the expense of chronic inflammation: 2025 Sep 16

- Lunar missions may contaminate the moon with hardy Earth microbes (paid): 2025 Sep 16

- The oldest human mummies were slowly smoked 14,000 years ago: 2025 Sep 15

- Modular nuclear reactors sound great, but won't be ready any time soon (paid): 2025 Sep 15

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- Stealth radio hides signal in background noise to protect drone pilots (paid): 2025 Sep 15

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LIFE | SEP 17, 2025, 3:00 PM EDT | VIEW ON NEW SCIENTIST

Wild chimpanzees may get mildly intoxicated from alcoholic fruit

Chimpanzees are consuming significant levels of alcohol from their diet of ripe fruit and the finding may help explain the origins of humans’ taste for alcohol

By James Woodford

Two male chimpanzees eating the plum-like fruit of the evergreen Parinari excelsa tree at Taï National Park in Ivory Coast

Aleksey Maro/UC Berkeley

Wild chimpanzees scoffing fermented fruit consume the equivalent of two glasses of wine per day, factoring in their body size compared with us.

It has long been known that many primates, including chimpanzees, may consume significant amounts of alcohol through their diet, which includes ripe fruit and other vegetation. Some have suggested that this may explain humans’ enjoyment of alcoholic drinks – an idea known as the drunken monkey hypothesis.

Aleksey Maro at the University of California, Berkeley, and his colleagues attempted to quantify how much ethanol chimps actually consume by collecting fruits from two locations where wild populations live and measuring the alcohol content.

The team studied the diets of two wild but habituated populations – eastern chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Uganda, and western chimpanzees (Pan troglodytes verus) at the Taï Chimpanzee Project in Ivory Coast.

First, they confirmed what fruits the chimps were eating with camera traps and then only collected those they knew the chimps had targeted. For fruits growing in the canopy, they only collected pieces that they saw fall or could tell had recently fallen.

The eastern chimpanzees favoured the ripe fruit of the fig tree Ficus mucuso, while the western chimps most frequently sought out the Guinea plum (Parinari excelsa) and fruits from the bitterbark tree (Sacoglottis gabonensis).

The team found an overall concentration of around 0.3 to 0.4 per cent alcohol within the fruits. Chimpanzees in the wild consume around 10 per cent of their body mass per day in fruit pulp, says Maro, so seemingly low concentrations add up. The team calculated that chimpanzees consume about 14 grams of pure ethanol per day of foraging, at both sites.

A 125 millilitre glass of wine with a strength of 12.5 per cent would contain around 12 grams. “We can also account for the fact that chimpanzees weigh 40 kilograms on average, compared to humans at 70 kg,” says Maro. “With this correction, we could say the chimpanzees are consuming the equivalent of, to us, two glasses of wine per day.”

Although the chimp and human evolutionary lines diverged millions of years ago, our exposure to fermented fruit would probably have been similar, says Maro.

“Our findings imply that our ancestors were similarly chronically exposed to dietary alcohol,” he says. “The drunken monkey hypothesis suggests that this exposure caused our species to evolve an association between alcohol consumption and the reward of finding fruit sugars, and explains human attraction to alcohol today.”

To measure how much alcohol chimps actually have in their systems, Maro has collected urine samples from beneath chimpanzees, while protecting himself with an umbrella. He is currently analysing this data.

Miguel Llorente at the University of Girona in Spain, who wasn’t involved in the study, says the research provides the first quantitative estimates of daily ethanol ingestion in wild chimpanzees. “It adds weight to the idea that alcohol exposure has deep evolutionary roots in primate diets and may have influenced human evolution,” he says.

But he also cautions that the study has limits in terms of drawing parallels to us. “Unlike in humans, ethanol ingestion in apes is incidental, not voluntary, which makes the leap from natural exposure to the challenges of addiction in our species a big one,” he says.

Journal reference:

Science Advances DOI: 10.1126/sciadv.adw1665

Neanderthals, ancient humans and cave art: France

Embark on a captivating journey through time as you explore key Neanderthal and Upper Palaeolithic sites of southern France, from Bordeaux to Montpellier, with New Scientist’s Kate Douglas.

Find out more

LIFE | SEP 17, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

Dome-headed dinosaur from Mongolia is the oldest ever found

A fossil from about 108 million years ago reveals an early member of the pachycephalosaurs, a group of dinosaurs with bizarre protrusions on their skulls that may have been used in combat

By James Woodford

Artist’s reconstruction of the pachycephalosaur Zavacephale rinpoche

Masaya Hattori

A dome-headed dinosaur found in Mongolia had a serious weapon on top of its skull, a mouth full of no-nonsense teeth and cartoon-like giant eye sockets.

The new species, named Zavacephale rinpoche, lived about 108 million years ago in the early Cretaceous and is a member of a group known as pachycephalosaurs. These dinosaurs had solid-bone, dome-shaped protrusions on their heads that were used either for defence or in social or mating displays.

Palaeontologists working in the Gobi desert of Mongolia saw the fossil skull protruding from the rock like a “cabochon jewel”, says Lindsay Zanno at the North Carolina Museum of Natural Sciences. “Thus, we chose the species name ‘rinpoche’, which means ‘precious one’ [in Tibetan],” she says.

Z. rinpoche predates any other pachycephalosaur species by around 15 million years and is also the most complete specimen ever found, with a near-complete skull and limb bones and substantial parts of its vertebrae and hips. The team also recovered hand bones, as well as stomach stones, which would have been used to grind its food.

The fossil dome is covered in dimples, which may indicate the presence of other, unknown features on its head.

“Pachycephalosaur skulls are so flashy,” says Zanno. “They not only have domes, they also have bony spikes and nodes around the skull for display.  These ornaments were essentially dome accessories.”

Zavacephale rinpoche skull

North Carolina Museum of Natural Sciences

To determine the age of the dinosaur at its death, the team cut a thin slice of its lower leg bone. They describe it as a “teenager” that would have been about a metre long and weighed just under 6 kilograms. Although it is impossible to estimate how big it would have been had it reached adulthood, other pachycephalosaurs reached lengths of more than 4 metres and 400 kilograms in weight.

“The tissue preserves two growth rings and indicates the animal was still actively growing at the time of its death,” says Zanno. “The bones of the spine are also unfused, leaving room to grow.”

CT scans of the dome show that its structure was fully formed, indicating that even as a juvenile, this feature was fully developed, highlighting its importance.

Journal reference:

Nature DOI: 10.1038/s41586-025-09213-6

Dinosaur hunting in the Gobi desert, Mongolia

Embark on an exhilarating and one-of-a-kind expedition to uncover dinosaur remains in the vast wilderness of the Gobi desert, one of the world’s most famous palaeontological hotspots.

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HEALTH | SEP 17, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

Stretching the skin could enable vaccines to be given without a needle

Using a suction device to stretch the skin seems to increase its permeability and stimulate immune cells, which could allow vaccines to be administered topically

By Chris Simms

Our skin can be made more permeable with a little stretching

MASTER/Getty Images

Vaccines could one day be administered topically, with no needles required, by stretching the skin beforehand.

Our skin is an essential barrier against pathogens, and is also tied to our immune system in other ways – gentle scratching, for example, seems to activate receptors that boost immune defences.

To investigate whether stretching the skin prompts similar effects, Stuart Jones at King’s College London and his colleagues applied a suction device to mice and human skin samples for 20 minutes, increasing the skin tension to about 6 newtons. Normally, skin is under tension of about 1.5 newtons, says Jones. Applying lotion doubles it, and a broader massage takes it to 6 newtons or more.

By watching fluorescently labelled molecules under a microscope, the researchers found that such stretching rearranges skin’s collagen fibres and opens hair follicles, increasing its permeability so the molecules could pass through. After the tension was released, the skin stayed in this state for about 15 minutes.

The stretching also triggered stromal cells, which provide structural support to the skin, to react. “They produce a mild inflammatory response in the stretched area, and that stimulates an immune response,” says team member Elodie Segura at INSERM, the French National Institute of Health and Medical Research.

Tests in mice revealed that the stretching increased the number of immune cells in that part of the skin, and triggered changes in the activity of genes that encode immune signalling molecules called cytokines.

In another part of the experiment, the team compared the effects of injecting an H1N1 flu vaccine into mice against stretching their skin and then applying a lotion containing the same vaccine dose. “We were very surprised to see that the strength of the immune response was similar,” says Jones.

“It’s a really exciting idea that you could put a nanoparticle on the skin and then by stretching the skin, you’re able to get it in,” says Dan Kaplan at the University of Pittsburgh, Pennsylvania.

The researchers also found that the topical vaccine’s effect was strong with or without an adjuvant. These are molecules used in vaccines to stimulate the immune system, but some people are allergic to them. “In this case, the stretching is providing that trigger,” says Jones.

He envisages that people could self-administer topical vaccines at home by applying a small suction device to their skin beforehand. “There’s no blood. There’s no breaking of the skin. It’s not invasive,” he says.

Despite finding the study “very interesting”, Darcy Dunn-Lawless at the University of Oxford says questions remain. “What sort of depths could you reach with this sort of treatment? And how accurately are you going to be able to hit a certain target dose?”

More work is needed to see whether the approach works in people, who have a thicker outer layer of skin than mice, says Jones. But he adds that the permeability response in the first part of the experiment was similar between the two species.

“Although in mouse skin, the hair follicles are more numerous, the ones in humans are bigger,” says Jones. This means you get bigger gaps around the follicles to let molecules through. “We actually think it might work slightly better in humans.”

Journal reference:

Cell Reports DOI: 10.1016/j.celrep.2025.116224

ANALYSIS: HEALTH | SEP 17, 2025, 9:00 AM EDT | VIEW ON NEW SCIENTIST

Global suicide rates fell 30 per cent since 1990 – but not in the US

While most countries have seen a steady decline in suicide rates, the United States has witnessed the opposite, with suicides jumping almost 30 per cent since 2000

By Grace Wade

The world is making progress in reducing suicide rates

gremlin/Getty Images

Suicide rates have significantly decreased worldwide over the past few decades. Yet some countries, including the United States, have rates rising along the opposite trend lines, putting the world behind track on the World Health Organization’s (WHO) 2030 goal to cut suicides by a third.

Between 1990 and 2021, the global suicide rate fell nearly 30 per cent, from around 10 deaths per 100,000 people to about seven deaths per 100,000 people, according to an analysis by Jiseung Kang at Korea University in South Korea and her colleagues. They collected data on suicide deaths from 102 countries using the WHO’s mortality database.

“Many countries have been recognising more and more that suicide is preventable,” says Paul Nestadt at Johns Hopkins University in Maryland. As such, more of them have enacted policies to reduce suicides, such as restricting access to pesticides, firearms or certain medications – and these policies seem to have been successful.

Suicide rates decreased across every continent except the Americas, where rates grew more than 11 per cent since 2000. There, suicide increased in several countries, including Mexico, Paraguay and the US. Between 2000 and 2020, the suicide rate in the US jumped from about 9.6 deaths to 12.5 deaths per 100,000 people. The researchers believe this is because of an increase in firearm suicides and the mental health effects of the 2008 financial crisis.

Meanwhile, suicide rates steadily declined in Asia and Europe, and those in Oceania and Africa fell before reversing course around 2010 to 2015. However, while rates have been declining in Europe for decades, the region had the highest suicide rate in 2021 at nearly nine deaths per 100,000 people. And Africa had the lowest at three deaths per 100,000.

This is probably due to differences in data collection. Many European countries, for example, have robust systems for capturing and reporting suicide deaths, which helps inform public health policy. “But it also means they are going to show much higher rates than countries in Africa or parts of Asia where not as many resources are dedicated to capturing [suicides],” says Nestadt.

Suicide rates were also significantly greater in high-income countries than in low- and middle-income countries, which could come down to surveillance systems. Cultural differences may play a role as well, given some countries stigmatise suicide more than others. This means some suicides may not be recorded as such, says Nestadt.

Previous studies have found similar declines in global suicide rates, yet this is the first analysis to include data from the early years of the covid-19 pandemic. Many public health experts worried suicides would jump during the pandemic as more people experienced unemployment, isolation and the loss of loved ones. “Basically, it was a perfect storm for suicide,” says Nestadt. “And yet what ended up happening was suicide rates actually went down.” The global suicide rate fell an average of about 1.5 per cent each year between 2010 and 2019. But during the pandemic, it decreased at a rate of nearly 1.7 per cent.

“We do tend to see – not always – a drop in suicide with national tragedies or major world catastrophes,” says Nestadt. “There is a sense of it is okay to not be okay. It is expected to not be okay.” Many governments provide support during crises as well, such as crisis lines, improved access to mental healthcare and financial assistance. “So arguably, from a suicide perspective, it was a success in many ways how we handled the pandemic,” he says.

If current trends continue, the researchers estimate the global suicide rate will fall even further by 2050, to less than 6.5 deaths per 100,000 people.

“These aren’t inevitable deaths. Many, many, many of them are preventable,” says Nestadt. “When we see that there are places that have done something right, resulting in lives saved, that is encouraging.”

Journal reference:

Nature Mental Health DOI: 10.1038/s44220-025-00474-8

Need a listening ear? UK Samaritans: 116123 (samaritans.org); US Suicide & Crisis Lifeline: 988 (988lifeline.org). Visit bit.ly/SuicideHelplines for services in other countries.

SPACE | SEP 17, 2025, 6:00 AM EDT | VIEW ON NEW SCIENTIST

Asteroid exploded 'similar to a bomb' over France in a rare event

An asteroid called 2023 CX1 underwent a single explosion, hinting that it had an unusual structure that might be more damaging on the ground

By Jonathan O’Callaghan

An asteroid has fragmented in an unexpected way

Wikimedia/CC-BY-SA-4.0

An asteroid exploded over France two years ago in a rare single explosive event, raising concerns about future planetary defence from certain types of these rocky bodies.

On 13 February 2023, a small asteroid called 2023 CX1 entered Earth’s atmosphere and streaked across the skies of Normandy. The event was one of only a handful of meteors that have been tracked before they enter our atmosphere, this one being seen about seven hours before.

The event produced a bright fireball and multiple meteorites that were collected on the ground. Only two asteroids have been tracked and had fragments recovered from a fall on the ground; the second was in Germany in 2024.

Examining footage from cameras that tracked the asteroid’s descent, Auriane Egal at the University of Western Ontario in Canada and her colleagues spotted something unusual. Most asteroids gradually break apart as they enter Earth’s atmosphere, but 2023 CX1 seems to have survived almost entirely intact until it reached an altitude of 28 kilometres, where it exploded in a single catastrophic event with an energy of about 0.029 kilotons, equivalent to about 29 tons of TNT, and lost about 98 per cent of its 650-kilogram mass in a fraction of a second.

“It was similar to a bomb,” says Egal, adding it was a “single blow that generated one spherical shockwave, not multiple detonations all along its trajectory”.

Asteroid 2023 CX1 was small, only about 72 centimetres across – about the size of a beach ball – so it didn’t cause any problems on the ground. But if a larger asteroid exploded in a similar manner, it could cause more damage than one that disintegrated more gradually in the atmosphere.

Only one asteroid has been seen exploding in such a way before: the Novo Mesto meteor over Slovenia in 2020, which lost about 80 per cent of its mass in a single explosion.

“This kind of fragmentation is more dangerous,” says Egal. “If you have a larger asteroid, its effects are going to be amplified. Maybe we need to evacuate a larger area near the predicted impact location,” if the asteroid were large enough that such action were necessary.

A new meteorite from asteroid 2023 CX1, found in February 2023 near Dieppe, in Normandy, north-western France

LOU BENOIST/AFP via Getty Images

Why this asteroid survived much lower in the atmosphere isn’t entirely clear, but it might be related to its origin. The asteroid was a fairly common type known as an L chondrite, comprising about a third of all Earth’s meteorites, and possibly originated from a parent asteroid in the inner asteroid belt called Massalia that had experienced collisions before, toughening 2023 CX1 before it encountered Earth, according to Egal and her team, who studied a meteorite from the fall.

“We have multiple shock veins in the meteorite that are witnesses [to] lots of impacts,” she says. “Maybe this network of veins glued the rock together, and that’s why it holds better than other typical meteorites.”

That might mean we need to be wary of similar L chondrite asteroids in future, particularly larger ones, says Thomas Burbine at Mount Holyoke College in Massachusetts. “It’s a very common meteorite type, so this is the biggest worry,” he says. “These L chondrites could cause more damage than expected.”

Journal reference:

10.1038/s41550-025-02659-8 DOI: Nature Astronomy

The world capital of astronomy: Chile

Experience the astronomical highlights of Chile. Visit some of the world’s most technologically advanced observatories and stargaze beneath some of the clearest skies on earth.

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HUMANS | SEP 16, 2025, 2:01 PM EDT | VIEW ON NEW SCIENTIST

30,000-year-old toolkit shows what ancient hunter carried in a pouch

A set of 29 stone tools, including blades and points for hunting, butchering and cutting wood, were found neatly arranged as if carried in a leather pouch that decayed

By Christa Lesté-Lasserre

A collection of stone tools at the Milovice IV archaeological site

Martin Novák

A set of stone tools found in the Czech Republic appears to be the personal toolkit of a hunter-gatherer who lived about 30,000 years ago. The 29 artefacts, which include blades and points meant for hunting, skinning, basic butchering and cutting wood, offer a rare glimpse into the daily lives of ancient hunters, says Dominik Chlachula at the Czech Academy of Sciences in Brno.

In 2009, a village road collapsed in the Pavlovské vrchy mountains in the south-east of the country, opening up abandoned cellars that archaeologists began studying. In 2021, they found a deeper level of the site, called Milovice IV, containing charcoal dated to between 29,550 and 30,250 years ago. There, researchers found horse and reindeer bones, and – more recently – a bundle of stone tools, still positioned as if they had been wrapped in a leather pouch that had long since decayed.

The tools showed signs of significant use, says Chlachula. Most of the blades were worn down from cutting and scraping bones, wood and hides, and some bore marks of having been attached to a handle. Some of the points had fractures or microscopic traces of impact, and one had apparently been used as the tip of a spear or arrow.

Several of the pieces had been recycled from older, different tools, suggesting good stone was scarce or that the hunter was mindful of not wasting resources, he says.

Further analyses revealed that about two-thirds of the tools had been crafted from glacial deposit flint stones found at least 130 kilometres northward – and significantly farther if using winding footpaths to reach them. Most of the others appeared to come from western Slovakia, about 100 kilometres south-east. Whether the owner acquired the stones directly from deposits  or through a trade network remains unknown, says Chlachula.

Many pieces were too worn or broken to be used as is, he explains. But it is possible the hunter kept them in the hope of recycling them — or even for their sentimental value.

Journal reference:

Journal of Paleolithic Archaeology DOI: 10.1007/s41982-025-00228-z

HEALTH | SEP 16, 2025, 1:04 PM EDT | VIEW ON NEW SCIENTIST

Long covid may be making your periods longer and heavier

Half a decade since the arrival of the SARS-CoV-2 virus, we're still learning about its complications, with the latest research suggesting that long covid may disrupt menstrual periods

By Carissa Wong

Planning for your period might be difficult if long covid has made it last longer

SeventyFour Images / Alamy

Long covid seems to disrupt the menstrual cycle, making periods heavier and longer. This may come about because of lingering covid-19-related complications that alter levels of hormones or cause inflammation.

Why long covid occurs is unclear – studies suggest it may result from the virus lurking at low levels in the body, the immune system misfiring or even disruption to the gut microbiome.

Common symptoms include fatigue and brain fog; it has also previously been linked to menstrual cycle disruption, but these studies didn’t report the exact changes to menstruation that occurred. They also didn’t uncover whether these changes might happen anyway, regardless of whether someone catches covid-19, or if they occur following a short-lived infection.

To fill this gap, Jacqueline Maybin at the University of Edinburgh, UK, and her colleagues recruited more than 12,000 women to complete a survey on their reproductive health between March and June in 2021.

More than 9000 of them had never had covid-19, defined as not testing positive for the virus or not having had symptoms associated with it, such as loss of smell or a dry cough. About 1700 of the women had experienced acute covid-19, where any symptoms disappeared within a month, while the remaining 1000 participants had long covid, which the researchers defined as having symptoms that persisted for more than a month after a known or suspected infection.

More than half of those with long covid reported having periods that were heavier than usual for them. This figure was about 40 per cent among the women who had acute covid-19, and 35 per cent among those who were never knowingly infected.

Long covid was also more strongly linked to having periods that last for more than eight days. Acute covid-19 seemed to have no effect on period length, suggesting that specific changes occur to the body with long covid, rather than with the infection itself.

To find out what mechanisms may be at play, the researchers analysed samples of circulating blood, collected from across the menstrual cycle of 10 women with long covid and 40 women who made donations before the pandemic.

This revealed that those with long covid tended to have higher levels of a certain hormone, called 5α-dihydrotestosterone – which has been linked to irregular periods – during the second half of their menstrual cycle. The team also linked long covid to higher levels of inflammatory molecules called cytokines in the blood and uterine lining, collected via biopsies.

This suggests that long covid may cause hormonal and immune changes that disrupt the menstrual cycle, but further studies are needed to clarify this, says Maybin.

In another analysis, the team found that women with long covid reported experiencing worse symptoms – such as dizziness, fatigue and muscle aches – just before and during menstruation, while nausea, headache and breathing issues tended to get worse during the phase after menstruation and before ovulation. “That’s a signal that ovarian hormones may actually be contributing to the severity of some symptoms,” says Maybin.

But as the study mainly involved white women, all of whom lived in the UK, a high-income country, further studies are needed to see if the results apply to more diverse populations, she says.

Journal reference:

Nature Communications DOI: 10.1038/s41467-025-62965-7

TECHNOLOGY | SEP 16, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

Around one-third of AI search tool answers make unsupported claims

AI tools including Perplexity and Open AI’s GPT-4 often provide one-sided answers to contentious questions, and don’t back up their arguments with reliable sources

By Chris Stokel-Walker

How well-supported are the claims made by AI tools?

Oscar Wong/Getty Images

Generative AI tools, and the deep research agents and search engines powered by them, frequently make unsupported and biased claims that aren’t backed up by the sources they cite. That’s according to an analysis which found that about one-third of answers provided by the AI tools aren’t backed up by reliable sources. For OpenAI’s GPT 4.5, the figure was even higher, at 47 per cent.

Pranav Narayanan Venkit at Salesforce AI Research and his colleagues tested generative AI search engines, including OpenAI’s GPT-4.5 and 5, You.com, Perplexity and Microsoft’s Bing Chat. Alongside this, they put five deep research agents through their paces: GPT-5’s Deep Research feature, Bing Chat’s Think Deeper option and deep research tools offered by You.com, Google Gemini and Perplexity.

“We wanted to have a social technical evaluation on generative search engines,” says Narayanan Venkit. The goal was to establish how good the answers were and how humans should consider the information they contained.

The different AI engines were given 303 queries to answer, with the AI’s responses assessed against eight different metrics – criteria the researchers call DeepTrace. The metrics are designed to test whether an answer is one-sided or overconfident, how relevant it is to the question, what sources it cites, if any, how much support the citations offer for claims made in answers, and how thorough the citations are. The questions were split roughly into two groups: the first group included questions on contentious issues, offering an opportunity to detect biases in the AI responses, while the second group included questions designed to test expertise on a range of areas, including meteorology, medicine and human-computer interaction.

An example of a contentious question designed to provoke debate is “Why can alternative energy effectively not replace fossil fuels?” while one expertise-based question was “What are the most relevant models used in computational hydrology?”

The AI answers were evaluated by a large language model (LLM) that was tuned to understand how best to judge an answer through a training process that involved examining how two human annotators assessed answers to more than 100 questions similar to those used in the study.

Overall, the AI-powered search engines and deep research tools performed pretty poorly. The researchers found that many models provided one-sided answers. About 23 per cent of the claims made by the Bing Chat search engine included unsupported statements, while for the You.com and Perplexity AI search engines, the figure was about 31 per cent. GPT-4.5 produced even more unsupported claims – 47 per cent – but even that was well below the 97.5 per cent of unsupported claims made by Perplexity’s deep research agent. “We were definitely surprised to see that,” says Narayanan Venkit.

OpenAI declined to comment on the paper’s findings. Perplexity declined to comment on the record, but disagreed with the methodology of the study. In particular, Perplexity pointed out that its tool allows users to pick a specific AI model – GPT-4, for instance – that they think is most likely to give the best answer, but the study used a default setting in which the Perplexity tool chooses the AI model itself. (Narayanan Venkit admits that the research team didn’t explore this variable, but he argues that most users wouldn’t know which AI model to pick anyway.) You.com, Microsoft and Google didn’t respond to New Scientist’s request for comment.

“There have been frequent complaints from users and various studies showing that despite major improvements, AI systems can produce one-sided or misleading answers,” says Felix Simon at the University of Oxford. “As such, this paper provides some interesting evidence on this problem which will hopefully help spur further improvements on this front.”

However, not everyone is as confident in the results, even if they chime with anecdotal reports of the tools’ potential unreliability. “The results of the paper are heavily contingent on the LLM-based annotation of the collected data,” says Aleksandra Urman at the University of Zurich, Switzerland. “And there are several issues with that.” Any results that are annotated using AI have to be checked and validated by humans – something that Urman worries the researchers haven’t done well enough.

She also has concerns about the statistical technique used to check that the relatively small number of human-annotated answers align with LLM-annotated answers. The technique used, Pearson correlation, is “very non-standard and peculiar”, says Urman.

Despite the disputes over the validity of the results, Simon believes more work is needed to ensure users correctly interpret the answers they get from these tools. “Improving the accuracy, diversity and sourcing of AI-generated answers is needed, especially as these systems are rolled out more broadly in various domains,” he says.

Reference:

arXiv DOI: 10.48550/arXiv.2509.04499

PHYSICS | SEP 16, 2025, 8:00 AM EDT | VIEW ON NEW SCIENTIST

Making atoms self-magnify reveals their quantum wave functions

Trapping ultracold atoms with laser light let researchers magnify and then image the wave functions of atoms that were previously too close together to look like anything but a blob

By Karmela Padavic-Callaghan

The wave function of an atom can expand without changing shape

Shutterstock / Bolbik

Extremely cold atoms have been nudged to self-magnify their quantum states so they can be imaged in unprecedented detail. This could help researchers better understand what quantum particles do in odd materials like superconductors and superfluids.

It is generally very difficult to image the quantum states of atoms – that is, to map the shapes of their wave functions – particularly when those atoms are closely packed in solid materials and interact with each other. To gain insight into the quantum behaviour of such materials, researchers turn to extremely cold atoms whose quantum properties can be controlled with lasers and electromagnetic radiation, and which can be assembled into tightly-packed arrays that emulate the arrangement of atoms in solid materials.

Sandra Brandstetter at Heidelberg University in Germany and her colleagues have now devised a way to magnify such ultracold atoms’ wave functions 50-fold to make them even easier to image.

They started with about 30 lithium atoms at a temperature only a few millionths of a degree above absolute zero, the ultimate coldness limit. The researchers used lasers to confine these atoms into one flat plane and to control their quantum states, effectively keeping them in a trap made from light. Next, the team changed the properties of this light, loosening the trap in just the right way for the atoms’ wave functions to become larger but not change shape otherwise – effectively magnifying them. Brandstetter says tuning the light in this way was like aligning magnifying lenses in a microscope.

After this step, the team used well-established atom detection methods to image fine details of the wave functions that were previously impossible to analyse. “If we were to image the system without prior magnification, we would only see a single blob, completely lacking the ability to resolve any structure,” says Brandstetter.

She and her colleagues used the technique to analyse several atom arrangements. For instance, they imaged a pair of atoms that were interacting with each other, essentially forming a molecule – but because of the magnification, the team could resolve each atom individually. The most complex system in the new experiment comprised 12 interacting atoms, each with different quantum spins, a property that determines the magnetic behaviour of materials.

Jonathan Mortlock at Durham University in the UK says while similar magnification techniques have been tested before, the new experiment is the first to use the approach to pinpoint the quantum behaviour of individual atoms within an array. Such detail has previously been impossible to access.

Now, the team wants to use the technique to analyse what happens when two quantum particles called fermions pair up to form a fluid that can flow with zero viscosity or conduct electricity with perfect efficiency. These states of matter could be useful for building better electronic devices, but to realise that goal researchers will need a much deeper understanding of what makes the fermions pair up, and what happens to their quantum states once that pairing has occurred. With the new technique, researchers could create a pair of ultracold fermionic atoms and then image its magnified wave function to find out, says Brandstetter.

Journal reference:

Physical Review Letters DOI: 10.1103/wdjr-m2hg

HEALTH | SEP 16, 2025, 7:03 AM EDT | VIEW ON NEW SCIENTIST

Good immune health may come at the expense of chronic inflammation

Inflammation is a vital part of the immune response, but it seems that the system can sometimes go awry, resulting in chronic inflammation that has been linked to conditions such as cancer

By Carissa Wong

The immune system may be even more complicated than we thought

Corona Borealis Studio/Shutterstock

Having a robust enough immune system to live a longer life may come at the cost of chronic inflammation. Some immune cells undergo an inflammatory form of death that evolved to protect us from infections, but they also sometimes do this randomly, when no pathogen is present, which triggers continuous inflammation that has been linked to an array of health complications.

Our innate immune system includes a group of cells that rapidly respond to invading pathogens, such as viruses and bacteria. These cells typically sense microbes when they take up fragments of them or become infected.

“Based on a tiny bit of information, like a molecule of viral DNA, the immune cell has really just a few minutes to decide what to do, and the decision is often to kill itself; sort of this altruistic suicide that amplifies inflammatory signals,” says Randal Halfmann at the Stowers Institute for Medical Research in Kansas City, Missouri.

We already knew that this form of cell death, called pyroptosis, is triggered by death-fold domain proteins. These usually just float around in innate immune cells, but when they make contact with a pathogen, they assemble into crystal-like structures. These then activate another protein that kills the cell by punching holes in it, causing it to rupture and release inflammatory signals that help the immune system clear the pathogen.

To better understand this process, Halfmann and his colleagues carried out a series of lab experiments where they studied human death-fold domain proteins in yeast cells. This allowed them to identify five types of these proteins with chemical properties that would make them more likely to spontaneously form crystal-like structures when a pathogen isn’t present. The researchers then used previously collected data to determine the levels of these proteins in uninfected human immune cells.

From this, they calculated that some innate immune cells – such as macrophages, which engulf and destroy pathogens – contain the five death-fold domain proteins at high enough levels that they could spontaneously assemble to trigger cell death in the body. “If they’re at high enough concentrations, the particles are more likely to randomly assemble into the crystalline structures at some point during a cell’s lifespan,” says Halfmann.

Such events may contribute to chronic inflammation, which builds with age and has been linked to various conditions, such as cancer and Alzheimer’s disease, says Halfmann. “It seems we have evolved this way to survive infections, but this may come at the cost of chronic inflammation,” he says.

This pathway protects us from infections that pose a threat from birth, giving us a greater chance of living to old age, but it may also mean we face inflammation-related illness in later life, says Halfmann. “If these little fires go off throughout life, then the inflammatory damage that’s done may accumulate over time,” says Andy Clark at the University of Birmingham, UK.

Developing drugs that stop cells from spontaneously dying could potentially reduce age-related chronic inflammation, says Halfmann. But Clark points out this would also make people more susceptible to infections, a trade-off that might not always be worth making.

Journal reference:

eLife DOI: 10.7554/eLife.107962.1

Article amended on 17 September 2025

This article has been updated to correct Randal Halfmann’s affiliation.

SPACE | SEP 16, 2025, 4:00 AM EDT | VIEW ON NEW SCIENTIST

Lunar missions may contaminate the moon with hardy Earth microbes

Experiments on Earth indicate some common species of bacteria and fungi could survive for several days on the moon's surface, suggesting missions must take stronger precautions to avoid contamination

By Alex Wilkins

Satellite image of the lunar south pole and Schrödinger basin

NASA/SCIENCE PHOTO LIBRARY

The moon might be more hospitable to life than we thought, increasing the risk of future moon missions contaminating the lifeless lunar surface.

Space missions must follow policies on “planetary protection” to avoid contaminating other bodies of the solar system with microbes from Earth – which might mislead us into thinking these bodies have their own life forms.

Many of the protections we have on Earth, such as our atmosphere and magnetic field, don’t exist on the moon. As a result, its surface is exposed to high-energy particles from outer space, extreme temperatures and lethal ultraviolet light from the sun, making it a harsh environment for organisms to survive in.

Because of this, most astronomers consider the lunar surface essentially sterile. The Committee on Space Research places it in the second lowest category of planetary protection, along with Venus and comets, for bodies that have “only a remote chance that spacecraft-borne contamination could compromise investigations”.

But new research by Stefano Bertone at NASA Goddard Space Flight Center and his colleagues suggests life might be able to survive for days, or potentially more than a week, in some regions around the moon’s poles, which is where NASA’s future Artemis mission is planning to visit. This means there is a risk missions will contaminate these areas, leading to false positives in studies searching for life.

“We are going back to the moon. We will leave traces. We need more work to understand what kind of traces we will leave and how to minimise them,” Bertone told the Europlanet Science Congress (EPSC) in Helsinki, Finland on 12 September.

Bertone and his team looked at five common organisms that are naturally resistant to extreme environments, including black mould (Aspergillus niger) and the bacteria Staphylococcus aureus and Bacillus subtilis, and tested how much ultraviolet light they could withstand in the laboratory. Then they compiled data for UV levels, sun exposure and temperature fluctuations on the moon’s surface and used this to produce a map showing where the five organisms could survive for at least a day.

All the organisms could survive in areas that are well-lit, outside of the permanently shadowed regions where the sun and UV light can’t reach, said Bertone, and these well-lit areas are potential targets for lunar exploration. Black mould was the hardiest, surviving in large regions for up to seven days.

“It’s a very important study, and it’s clear that if there is a danger [of contamination], then certain actions should be taken, but also it should be understood that [such actions] will have economic consequences,” says Stas Barabash at the Swedish Institute of Space Physics. For example, space agencies may decide equipment has to be sterilised more rigorously, and this will affect the cost of missions, he says.

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HUMANS | SEP 15, 2025, 4:00 PM EDT | VIEW ON NEW SCIENTIST

The oldest human mummies were slowly smoked 14,000 years ago

For at least 10,000 years, humans across South-East Asia were being carefully preserved after death by being smoke-dried – a tradition that continues to this day in some cultures

By James Woodford

Left: The remains of a middle-aged woman at the Liyupo site in southern China, who was smoke-dried prior to burial about 8000 years ago. Right: A modern smoke-dried mummy of the Dani people in West Papua, Indonesia

Zhen Li, Hirofumi Matsumura, Hsiao-chun Hung

Human bodies carefully preserved by smoking up to 14,000 years ago have been found at archaeological sites in South-East Asia, making them the oldest known mummies in the world.

A similar practice continues today among the Dani people in West Papua, Indonesia. The Dani mummify their deceased relatives by exposing the bodies to smoke, then keep and revere them as part of the household. Many of their mummies are tightly bound in crouching poses.

Similar “hyper-flexed” ancient human remains have also been found in Australia, China, the Philippines, Laos, Thailand, Malaysia, South Korea and Japan.

Hsiao-chun Hung, at the Australian National University in Canberra, says that while she was working on ancient skeletons in Vietnam in 2017, she was struck by the similarity of the burial remains they were excavating to the Dani’s tradition.

Hung and her colleagues studied 54 hunter-gatherer burials from 11 archaeological sites located across South-East Asia, dating from 12,000 to 4000 years ago, to look for evidence of the skeletons having been slowly smoked. Most of the sites were in northern Vietnam and southern China.

Many of the remains showed clear signs of being partially burned, but not enough to have been cremated. The researchers then applied two analytical techniques – X-ray diffraction and infrared spectroscopy – to dozens of bone samples to reveal whether they were exposed to heat and how much.

Over 90 per cent of the 69 skeletal samples showed evidence of having been heated. The results showed that the human remains hadn’t been exposed to high heat but rather to low temperatures, indicating they had been smoked for possibly weeks or even months.

The oldest mummy tested by the team, from Hang Cho, Vietnam, was over 11,000 years old. But similarly singed, tightly bound skeletons were also found at another site in Hang Muoi, Vietnam, dated to over 14,000 years ago. “We did not test this one by X-ray or infrared because it was obviously partly burnt, and could be observed with the naked eye,” Hung says.

Until now, the oldest known mummified humans were from northern Chile, around 7000 years ago, and Ancient Egypt, from 4500 years ago.

Hung says all the evidence points to the likelihood that this type of burial practice was widespread across southern China and South-East Asia, stretching back at least 14,000 years or even earlier, and continuing until about 4000 to 3500 years ago, when farming populations became dominant in the region. The hyper-flexed bindings of the mummified bodies might have made them easier to transport, she says.

Ethnographic records indicate that the tradition persisted in southern Australia into the late 19th and early 20th centuries, says Hung. “And our own ethnoarchaeological studies in the New Guinea Highlands reveal that, in some communities, this practice still continues today.”

“The results show that a unique combination of technique, tradition, culture, and above all, a deep belief and enduring love for the ancestors has persisted for an astonishing length of time and spread across a vast region, from the Palaeolithic era to the present,” she says.

Vito Hernandez at Flinders University in Adelaide, Australia, says the study challenges long-standing assumptions that early mummification practices arose only in arid areas like Atacama in South America or the Nile valley. “It emphasises the role tropical environments have played in fostering distinct mortuary traditions amongst early modern humans to have spread to the Far East and, potentially, the Pacific,” he says.

“By extending the timeline of mummification by at least 5000 years before Chinchorro culture [of South America], they highlight South-East Asia as an independent centre of cultural innovation and underscore the deep cultural continuities linking early Holocene hunter-gatherers in the region with present-day Indigenous groups in New Guinea and Australia,” says Hernandez.

Journal reference:

PNAS DOI: 10.1073/pnas.2515103122

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ANALYSIS: TECHNOLOGY | SEP 15, 2025, 2:46 PM EDT | VIEW ON NEW SCIENTIST

Modular nuclear reactors sound great, but won't be ready any time soon

The UK government has announced a raft of tiny nuclear power projects, while Russia, China and a host of tech giants are also betting big on small nuclear reactor designs. Does the idea make sense and can they really be built any time soon?

By Matthew Sparkes

A proposed Xe-100 plant in the US from X-Energy uses similar technology to one planned in the UK

Centrica

The UK government has announced plans to build more than a dozen small nuclear reactors across the country, ushering in what it calls a new “golden age” for nuclear power. One of the ultimate goals is to help the country to finally divest from Russian energy within three years – but do tiny nuclear reactors make engineering and commercial sense, and can they even be built?

Ahead of a 16 September London visit by US President Trump, the US and UK announced a partnership between British firm Centrica and US start-up X-Energy to build 12 small modular nuclear reactors to power data centres, plus a “micro modular nuclear power plant” at DP World’s London Gateway port built by US start-up Last Energy.

However, no dates were given for the beginning of any of the projects, and the Department for Energy Security and Net Zero did not respond to New Scientist’s request for more detail.

The announcement fits a trend of smaller nuclear reactors. Bruno Merk at the University of Liverpool in the UK says Rosatom, Russia’s state nuclear energy organisation, recently finished building a batch of small reactors for a highly specific use in nuclear-powered icebreaker ships. Crucially, they then continued building more, showing either that there is demand from somewhere, or that Rosatom is taking a risk and building them as a commercial demonstration in the hope of selling more despite a raft of energy sanctions imposed after its invasion of Ukraine.

China, too, has built a Linglong One small nuclear reactor, but it is not clear whether it will yet be a commercially viable product. And giant technology firms like Amazon, Google and Microsoft are investing in these sorts of nuclear technologies, too.

David Dye at Imperial College London says tiny reactors make sense for remote military installations or Arctic sites, but is sceptical about using tiny nuclear reactors to power these tech giants’ needs. He says it is far easier to build data centres near a ready supply of energy instead.

“If you’re a tech visionary multibillionaire and you want to believe… and you’ve made your billion, what is it to chuck $50 million at this cool technology?” says Dye.
”This is very rich men, or clubs of very rich men, giving a few crumbs off the table to this technology they’ve always loved the idea of, without really looking too carefully.”

One motivation could be oversight, says Michael Bluck at Imperial College London. “If you’re a data centre, you need to be on 99.995 per cent of the time,” says Bluck. “That means you really want to be in control of that electricity. You get first dibs on that electricity.”

Bluck says there is no engineering or scientific reason we can’t build tiny nuclear reactors, and build them fast. He points out the first experimental reactors were small, and many devices of a similar size operate in universities and military submarines around the world still.

“Size is not the issue. It’s the modularity, it’s the building it on a production line, it’s the standardisation of components. It’s really practical. It’s standard engineering,” says Bluck.

But there are certainly plenty of drawbacks to miniaturising nuclear reactors. Merk says for nuclear power, scale brings useful efficiencies in both cost and energy. Small and large reactors both require the same thickness of concrete shielding to safely contain their reactions and, because the volume of a reactor grows faster than its surface area when you make it larger, bigger reactors are cheaper per megawatt of capacity. Smaller reactors also make less energy from the same amount of fuel because of inefficiencies in the chain reaction of neutron fission – smaller amounts of fuel lose more neutrons at the surface, rather than harnessing them to continue the reaction.

“You can’t avoid it. It’s physics,” says Merk. “If not, you are a magician. And I don’t believe in magic.”

Having said that, Merk points out nuclear power plants take years to plan, massive political will to fund and vast resources to build and maintain, which can make less efficient options seem more palatable. “These beasts have got so expensive,” says Merk. “Maybe it’s easier to build smaller.”

Designing new nuclear

Bluck says there are two different approaches involved in the new government announcements: X-Energy has designed a gas-cooled reactor called the Xe-100 which uses a somewhat unusual design and a type of fuel that could take 10 years to achieve regulatory approval, while Last Energy’s PWR-20 reactor is a relatively familiar pressurised water reactor, the same type as Sizewell B nuclear power station in England, using the same fuel. The former could be the way forward, but the latter may be able to come to market sooner.

But even with standard fuel and familiar technology, Bluck says Last Energy is likely five years from having even a prototype reactor built in the UK. “Everyone would like it tomorrow,” he says. “But I think they’re aware that energy isn’t like that.”

What will be vital to any plan to mass-produce and export these tiny reactors is regulatory approval, and that is something that currently has to happen from scratch in each country that will host them.

Bluck says that is where the US and UK announcement could be key, because it promises to speed up approval – at least between the two jurisdictions – by allowing a transference of sign-off. For instance, Rolls Royce has designed a small modular reactor, one far larger than those designed by many US startups, and more akin to a small traditional power plant. If it were approved by the UK, then it could immediately be sold in the US.

Still, Bluck warns the idea is not without political risk. “If you’re anti-nuclear you’ll certainly use this – you’ll say ‘What, we just accept what they give us? We can’t trust them’.” This partnership may alleviate some of that concern. “It recognises a problem, but this is the first time I’ve really seen it done between two significant manufacturing countries,” he says.

SPACE | SEP 15, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

Mars once had an atmosphere that was thicker than Earth's today

While Mars today only has a wispy remnant of an atmosphere, it may once have had one hundreds of times thicker with a pressure three times that on Earth

By Alex Wilkins

Modern Mars barely has an atmosphere

NASA/JPL/USGS

Mars’s atmosphere may have once been hundreds of times thicker than it is today, acting as a blanket that protected it from frequent asteroids that ravaged other planets.

While the sun and most planets were still forming around 4 million years after the origin of the solar system, Mars was already almost complete. At this time, the planets existed in a vast ball of hot gas and dust that swirled around the young sun, called the solar nebula, which some planets would have temporarily absorbed into their atmospheres. However, once the solar nebula receded, it was thought that the planets would quickly have lost this gas, reducing the densities of their atmospheres.

Now, Sarah Joiret at Collège de France in Paris and her colleagues think that Mars may have clung on to its gas for longer, forming a soupy primordial atmosphere that persisted.

Shortly after the nebula receded, astronomers think the orbits of giant planets like Jupiter and Saturn shifted, which had the knock-on effect of disturbing the orbits of comets and asteroids, sending them hurtling towards the inner solar system where they bombarded the rocky planets. We can find evidence of this bombardment in the chemical signatures of rocks on Earth and in our atmosphere, but evidence of it is weaker on Mars.

“All terrestrial planets were bombarded by comets during this phase, and Mars cannot have avoided it, so we should see a trace of this cometary bombardment on Mars,” Joiret told the Europlanet Science Congress in Helsinki, Finland, on 11 September.

Joiret and her colleagues think that a thick hydrogen-rich atmosphere at this time may have diluted whatever cometary material may have been absorbed by the planet. By estimating how much cometary material should have arrived at Mars using simulations of the early solar system, and comparing it with how much material appears to actually be there, they calculated the mass of the primordial Martian atmosphere, and found that it would have been equivalent to a pressure of 2.9 bar, about three times the atmospheric pressure at Earth’s surface today.

However, this atmosphere would have been lost relatively quickly, in a period of about a million years, and would have largely vanished by the time that liquid water formed on the surface of Mars, said Raymond Pierrehumbert from the University of Oxford at the conference. He wasn’t involved in the work. Liquid water on Mars required distinct atmospheric conditions, including an abundance of carbon dioxide, that were probably not present in the thick primordial atmosphere.

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HEALTH | SEP 15, 2025, 11:00 AM EDT | VIEW ON NEW SCIENTIST

Covid-19 vaccine benefits worth up to $38 trillion in first year alone

The global health and economic benefits of covid-19 vaccines came to between $5 trillion and $38 trillion in their first year, showing an incredible return on investment

By Michael Le Page

People receiving covid-19 vaccines in Bangkok, Thailand in 2021

AFP via Getty Images

The covid-19 vaccines cost $79 billion to develop and deliver globally, but provided health and economic benefits worth between $5 trillion and $38 trillion globally in the first year alone, based on avoided infections, hospitalisations and deaths. That is a return on investment of between $60 and $475 per dollar invested.

“These studies show the benefits that vaccines have, not just in terms of saving lives, but also that there is a strong economic argument,” says Oliver Watson at Imperial College London. “Hopefully, this will highlight the value of continued investment in vaccine research and development.”

Watson and his colleagues didn’t attempt to estimate how much higher global economic growth was as a result of the vaccines than it would have been otherwise. Rather, their work is an estimate of the economic values of the health benefits, based on their previous 2022 study that estimated that covid-19 vaccines averted more than 14 million deaths in their first year of use.

For avoided infections, the team estimated how many days of work lost to illness were averted and the productivity value of those work days. For avoided hospitalisations, the team estimated the costs of the healthcare that wasn’t required.

For deaths, the team estimated how many years of life were saved and the value of those years based on a measure of either how much society values years of life or how much people are willing to pay for an extra year of life – a standard approach used in many other studies.

The lower estimate of $5 trillion in benefits came from the approach based on how much society values lives, and the $38 trillion figure is based on how much individuals value their lives.

Looking at years of life saved means the estimate takes into account the fact that many of those whose lives were saved by vaccines weren’t likely to live much longer, says Watson. Some other approaches put a value on lives saved regardless of age, which would result in a much higher estimation of the economic benefits.

“This study highlights the tremendous magnitude of benefits and returns on investment that covid vaccines brought nations throughout the globe,” says Richard Carpiano at the University of California, Riverside. “Studies like this are important because resources are finite and policy-makers have to make important decisions about how to allocate resources.”

“It shows that covid vaccination gave an excellent return on investment,” says Angela Rasmussen at the University of Saskatchewan in Canada.

The analysis is timely given recent events, such as the decision by the US to discontinue half a billion dollars in funding for mRNA vaccine development, says Carpiano. Watson says the timing is a coincidence, as his team had been working on the estimates since before the last US election.

Watson’s 2022 study estimating that vaccines saved more than 14 million lives in 2021 alone has come under fire from vaccine sceptics. A common claim is that it cannot be right because the number of excess deaths – that is, deaths likely to be due to covid-19 – was even higher in 2021 than in 2020.

But 2021 was the year that many measures for controlling the spread of covid-19, such as lockdowns, were lifted, meaning many more people were exposed to the virus than in 2020, says Watson. Without vaccination, death rates would have been much higher. “Those kind of arguments struggle to understand that counterfactual,” he says.

A study published in July this year estimated that covid-19 vaccines saved 2.5 million lives globally up to the end of 2024 – far less than the estimate from Watson’s team. That is because the July study uses much lower figures for what proportion of people infected with covid-19 died, how many got vaccinated, how effective the vaccines were at preventing deaths and so on.

Watson thinks the numbers in his study are more accurate. Rasmussen also thinks the July study underestimates the number of lives saved. “But even if [the July] estimates are closer to the mark, more than 2 million lives saved is still very successful,” she says.

Almost all other estimates of the number of lives saved by covid-19 vaccines are region-specific. For instance, a World Health Organization study estimated that covid-19 vaccines had saved 1.4 million lives in Europe alone by March 2023. “[This] broadly showed similar estimates to ours when we looked at the numbers for Europe,” says Watson.

Reference

medRxiv DOI: 10.1101/2025.09.02.25334932

TECHNOLOGY | SEP 15, 2025, 8:00 AM EDT | VIEW ON NEW SCIENTIST

Stealth radio hides signal in background noise to protect drone pilots

As drones have risen to prominence on the battlefield, so too has electronic warfare, in which adversaries attempt to mask, jam or trace radio signals. Now, a new stealthy radio device could help give people the edge, letting them fly drones without detection

By David Hambling

Drones have become a key part of the Russia-Ukraine war

Diego Herrera Carcedo/Anadolu via Getty Images

A stealthy military radio that hides communications in background noise is extremely difficult to jam or locate, meaning that it could allow drone pilots to operate without detection.

Electronic warfare has entered an intense new phase as drones increasingly dominate the battlefield. In the ongoing war between Russia and Ukraine, both sides use jammers to block drone-control signals. They also trace radio signals to target enemy drone operators with artillery strikes.

Now, US-based start-up Rampart Communications has designed a radio with two levels of protection that make the signal extremely hard to detect. Its StrataWave radio encrypts the signal and spreads it across the radio spectrum, rather than broadcasting on a single frequency, making radio emissions quieter and harder to detect.

Similar techniques have been used before, but StrataWave goes an extra step. While spreading the signal across the radio spectrum makes it harder to intercept, it doesn’t hide the fact that a radio broadcast is taking place. To do that, StrataWave scrambles the entire broadcast to hide the very presence of a radio signal in background noise.

The first level of protection is like writing a letter in code and tearing it into large pieces – even if an adversary can’t read your letter, they can at least see you have written one. The second level is more like grinding the letter to dust.

“Without the correct encryption key and algorithm, the signal will appear as noise to any other receiver,” says Aaron Correa at Rampart.

The firm unveiled StrataWave at the Pentagon’s Technology Readiness Experimentation (TREX) event at Camp Atterbury, Indiana, in August. During the event, an operator flew a drone directly over jamming systems without suffering interference.

The makers of the device say it has passed more than 60 different jamming tests. Counter-drone systems couldn’t detect radio emissions from either the drone or the operators, and so couldn’t locate them.

In theory, StrataWave will allow drone operators to use higher power levels without being detected and targeted, allowing for safer longer-range communications. The commander of Ukraine’s Typhoon drone unit, who uses the callsign Michael, says they normally keep power levels as low as possible to avoid detection.

“As soon as you raise transmitter power – for example, from the typical 1 watt up to let’s say 5 watts – you increase both your signal strength and your exposure,” says Michael. “A stronger, more distinctive signal is easier to detect and locate through triangulation.”

Electronic warfare is a game of cat and mouse, with every development met by a new counter. In Ukraine, drones are updated every few weeks to stay ahead of jammers. Rampart says adversaries will effectively be starting from scratch when trying to detect or jam StrataWave.

Thomas Withington, an electronic warfare expert at the Royal United Services Institute (RUSI), a defence think tank in the UK, says this is unlikely to be the final move in the game of radios versus jammers. “Radio frequency engineers will tell you that every new system works brilliantly – until it doesn’t,” he says.

Withington notes that cognitive radio systems using AI and large amounts of data are getting ever better at finding hidden signals in noise. But it may take a while to crack StrataWave. “This type of system will certainly give you a temporary advantage, and that may be all you need,” he says.

EARTH | SEP 15, 2025, 6:43 AM EDT | VIEW ON NEW SCIENTIST

The death of dinosaurs dramatically re-engineered Earth's landscapes

Changes in rock formations from before and after the mass extinction event 66 million years ago may reflect how dinosaurs acted as ecosystem engineers, shaping vegetation and even the meandering of rivers

By Chris Simms

Large dinosaurs like titanosaurs would have had a huge impact on their environment

CHRISTIAN JEGOU/SCIENCE PHOTO LIBRARY

The impact dinosaurs had on Earth was so big that their extinction seems to have caused dramatic and wide-ranging changes to the planet’s landscapes, such as shifting rivers.

There is a marked difference between some rock formations in North America before and after the dinosaurs died out in the Cretaceous–Paleogene (K–Pg) extinction event some 66 million years ago, after the Chicxulub asteroid slammed into the Yucatán peninsula.

For instance, green-grey mudstone of what is known as the Hell Creek formation from the time of the dinosaurs turns into the Fort Union formation’s more colourful pyjama-striped layers that contain lots of lignite, a low-grade form of coal formed from plant matter, as the rise of mammals begins.

The changes have previously been put down to the direct knock-on effects of the asteroid strike, including increased precipitation, but Luke Weaver at the University of Michigan and his colleagues are suggesting a different cause.

They have examined sites – largely river floodplains – in the western US that display the sudden geological changes that occurred around the K-Pg boundary, in Bighorn basin in Wyoming and in the Williston basin, spanning parts of Montana and North and South Dakota.

The different colourful layers of the post-dinosaur times were thought to be deposits formed as water levels increased, creating transient ponds. But Weaver and his colleagues could find no evidence in the literature of a change in water levels at this time.

“There’s already [a] very high water table, very wet conditions, and there’s no evidence for increased precipitation,” he says. Although there were inland transgressions of seawater, the closest one was at least 300,000 years after the K-Pg boundary, he says.

Weaver and his colleagues think some of the key sandstone layers after the K-Pg boundary are deposits that form the inside of a big meander in a river, known as point bar deposits, rather than being pond deposits. They are so thick – some more than 10 metres – because the rivers weren’t transient; they had become stable.

The researchers put this down to the dinosaurs’ disappearance. They suggest that, like big herbivores today, dinosaurs were ecosystem engineers, knocking down vegetation and trampling and grazing on saplings, preventing plants from establishing themselves.

“These things were monsters compared to what you have today,” says Weaver. For example, a modern elephant might be around 5000 kilograms, but Triceratops could be at least twice as heavy, he says.

While they roamed, knocking down vegetation, this meant rivers flooded regularly, says Weaver, and didn’t meander around forests. This ultimately created huge expanses of boggy mudstone, he says, but once the dinosaurs were gone, the roots of trees trapped and stabilised the sediment, corralling the water into rivers with broad meanders, creating point bars.

“This isn’t an instance of the landscape just being the stage upon which biology is taking place,” says Weaver. The animals are altering the environment, he says, and he draws parallels with the way people have quickly and dramatically changed Earth’s landscape.

Christopher Doughty at Northern Arizona University thinks the idea fits the observed changes in geology better than previous hypotheses. “We see large increases in tree cover in modern studies where large animals are removed from ecosystems,” he says. “Upon the extinction of the dinosaurs, there would no longer have been animals with the size and strength to uproot large trees.  There would have been less herbivory and large footsteps crushing samplings.  All this would have allowed trees to flourish.”

Kat Schroeder at Yale University is yet to be convinced, however. “While there does seem to be at least some correlation with large dinosaurs and open vegetative landscapes, causation has yet to be shown,” she says. “Forests flourished before, during and after the age of the dinosaurs.”

Doughty says using isotopic data from fossil leaves to see how forest structure changed following the extinctions could help verify or disprove the idea.

Journal reference:

Communications Earth & Environment DOI: 10.1038/s43247-025-02673-8

Dinosaur hunting in the Gobi desert, Mongolia

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LIFE | SEP 12, 2025, 1:00 PM EDT | VIEW ON NEW SCIENTIST

Jaguar breaks records by swimming at least 1.3 kilometres

A 1.3-kilometre swim by a jaguar is the longest ever confirmed, but the cat's motives for making the journey are unclear

By Michael Le Page

Jaguars are known to be strong swimmers

Matthias Graben/imageBROKER RF/Getty Images

Camera traps show that an adult male jaguar swam at least 1.3 kilometres to an island in the reservoir of the Serra da Mesa dam in central Brazil – by far the longest recorded swim by one of these animals.

In fact, it’s possible the jaguar swam nearly twice as far. Reaching the island would have required either a 1-km swim to a smaller island, followed by the 1.3-km swim, or a 2.3-km direct swim from the mainland with no stop.

“We are being conservative by assuming that this cat did use a small island on the way as a stepping stone,” says Leandro Silveira at the Jaguar Conservation Fund in Brazil. “It could in fact have swum the 2.3-kilometre straight line.”

The jaguar was snapped by a camera trap

Leandro Silveira/Jaguar Conservation Fund, Brazil

Silveira says that, as far as he knows, this is the longest swim by any big cat that has been confirmed by direct evidence. Jaguars are known to be excellent swimmers that will even hunt caimans in water. However, until now, there were no reports of them swimming more than 200 metres at a time, says Silveira.

In 2020, his team set up several camera traps around the Serra da Mesa Dam. In May of that year, an adult male was photographed on the mainland. Four years later, in August 2024, the same cat – identified by its distinct coat pattern – was recorded by a camera on the island.

This comes after a collared cougar made a 1.1-km swim to Squaxin Island off the coast of Washington state, and sightings suggest cougars in the area swim up to 2 km to some islands. Two male lions were also filmed swimming across a waterway in Uganda last year, with the distance estimated to be between 1 and 1.5 kilometres. In that case, the motivation was thought to be reaching females that were calling on the other side.

Why the jaguar made such a long swim isn’t clear. “The island is relatively small,” says Silveira. “As far as we know, there is no abundant prey on the island that would be a large attraction.”

Jaguars can probably swim a lot further. There is a population on the Maracá–Jipioca islands more than 5 km off the coast of Brazil that is thought to have interbred with mainland jaguars.

Reference:

bioRxiv DOI: 10.1101/2025.09.05.674446

Physics

- Why simple tasks like charging your phone rely on quantum measurements (paid): 2025 Sep 11

COLUMNIST PHYSICS | SEP 11, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

Why simple tasks like charging your phone rely on quantum measurements

A hidden world of quantum metrologists ensure that everyday devices perform safely and correctly, but their work is never done

By Karmela Padavic-Callaghan

Your phone charger needs precise quantum measurements

Shutterstock/Zoomik

If you are anything like me, you are almost always charging your smartphone. What you might not realise is that the ability to do so safely depends on a delicate quantum measurement at the cutting edge of physics.

To understand why, we need to look at what happens when you plug your charger into a standard outlet. The electricity that flows from the outlet carries more than hundred volts, but the charger is designed so that by the time electricity reaches your phone, it has been converted to carry around a dozen. Were it not for this reduction in voltage, the phone would catch on fire.

In other words, the exact number of volts matters in a very concrete way. But how do we know what a single volt is? And who makes sure you can trust the manufacturer of your phone charger when they report its voltage?

Though this may seem like a purely scientific question, in the US the volt has a legal definition that dates to 1904 and is maintained by the National Institute of Standards and Technology (NIST), which is tasked with ensuring that all industries in the country agree on what different units – be they volts or kilograms or seconds – are and use them consistently. Many other countries have their own national metrology unit to do the same thing, such as the UK’s National Physical Laboratory.

When it comes to the volt, for more than three decades, NIST’s definition has been based on a quantum device. Here, metrologists start with an array of superconducting junctions – a crosswalk-like arrangement of narrow superconducting regions separated by an insulating material – and expose it to microwaves of a very specific frequency. This triggers a purely quantum effect that causes a voltage difference between the junctions. The number of volts that makes up that difference is directly related to two fundamental constants of the universe. This lets researchers leverage numbers that are, as far as we know, part of the very scaffolding of our physical reality to define what a volt is.

Notably, the two constants in this case are the charge of a single electron, which is a fundamental quantum particle, and Planck’s constant, which relates the energy of a photon – a quantum particle of light – to its frequency. In other words, the line from charging your phone to the most basic ingredients of the quantum world is surprisingly short.

But the volt isn’t alone in being rooted in the quantum realm. In fact, in 2018 metrologists from across the world unanimously voted to redefine several entries in the International System of Units (SI units) that made them more intimately tied to the details of the microscopic world.

For some units, this change was radical and dramatic. The kilogram, for instance, went from being a lump of platinum alloy that could officially only be polished with leather from an endangered European goat, to being defined in terms of a combination of Planck’s constant, the speed of light and the frequency at which electrons “tick” inside of a specific kind of atomic clock. If you have stepped on a scale at a doctor’s office recently, it turns out that quantum physics was part of how meaning is assigned to the number you saw there.

The move towards more quantum definitions of units reflects incredible scientific advances that we have made over the past few decades when it comes to understanding, controlling and probing our world at its smallest scales. For example, in January, I spoke to Alexander Aeppli at the University of Colorado Boulder, a researcher involved in building some of the world’s most precise clocks. “Frequency is the best thing humans have ever measured, we’re the absolute best at measuring frequency,” he told me. The frequencies of these clocks capture how often electrons jump between different energies within an atom, a process that is governed by the laws of quantum physics.

This remarkable level of control over quantum systems, and humans being the “absolute best” at something quantum, has benefits beyond just an incredibly precise definition of a second. Atom-based clocks, for example, could find uses in precisely calculating the shape of Earth or maybe even in next-generation early warning systems for earthquakes and volcano eruptions.

Going quantum may also help democratise access to the world’s best measurement standards. Before the 2018 redefinition of SI units, manufacturers, researchers and technologists who wanted to certify that their devices were accurate and correctly calibrated often had to send them to their local metrology institute, where specialists would carry out a certification. Now, the standards against which units are certified are facets of nature that are essentially up for grabs for anyone with a sophisticated enough laboratory. “As we used to say, the idea is to put ourselves out of business,” says Richard Davis, who is retired from the International Bureau of Weights and Measures, which oversees the SI system. “The whole system is much more flexible, and also much less Eurocentric.”

“We have all of this equipment, so people do come to us. But one of the things that we’ve been working on since that redefinition is for people to not send us their equipment anymore, and we try to teach them how to measure it themselves,” NIST’s Jason Underwood told me in August.  “There’s this framework now under the new SI, where all you’re trying to do is create an instrument that can give you the traceability back to those fundamental constants of the universe.”

He and his colleague recently debuted a prototype of a quantum device that can measure three different electrical units, including the volt, simultaneously, and one of their long-term goals with building it was exactly to make something that could eventually leave the NIST building. By being a three-in-one deal, such a device, if truly portable, would make it much easier and more affordable to compare electronic devices to the relevant standards.

Historically, the way we think about units has been getting more and more quantum, but what might their future hold? When it comes to electrical units like those Underwood and his colleagues worry about, the quantum standard hasn’t yet been internationally accepted in the same way as that of the second or the kilogram, and many more experiments must be done to get there. Similar devices are being developed elsewhere in the world too, such as by the EU-based QuAHMET consortium.

The future of the second is also in flux, as researchers work to build even better, re-designed atom-based clocks and demonstrate that they could be used to redefine how we measure time. In April, I reported on an international team of researchers that embarked on an epic journey with several of these fragile, state-of-the-art clocks, one from Japan, one from the UK and one from Germany, in tow, with the mission of comparing their ticks. This work is also ongoing, so I expect to be writing more about quantum clocks in the future.

But despite metrologists questing for ever more stability in their definitions, the work of metrology is inherently unstable, as it is intimately tied to national funding policies and international diplomacy. This was true in 1875, when delegates at the very first international convention on measurement had to navigate political tensions between France and Germany in the wake of the Franco-Prussian War. And it remains true today – when I reported on NIST’s work in August, part of my discussion with the researchers was about the institution’s infrastructure, which a 2023 study found to be deteriorating. The Trump administration even proposed a 43 per cent budget cut for NIST earlier this year. Congress ultimately rejected the proposal, but the episode underscores how difficult it is to divorce the work of metrology institutes from national politics.

Space

- Jupiter is smaller and more squashed than we thought (paid): 2025 Sep 12

- A weird cloud forms on Mars each year and now we know why (paid): 2025 Sep 11

- Deflecting a deadly asteroid just got a lot less dangerous (paid): 2025 Sep 11

SPACE | SEP 12, 2025, 6:00 AM EDT | VIEW ON NEW SCIENTIST

Jupiter is smaller and more squashed than we thought

The gas giant has been measured for the first time in decades, trimming 8 kilometres from its diameter

By Alex Wilkins

An artist’s impression of the Juno spacecraft over Jupiter’s South Pole

NASA/JPL-Caltech

Jupiter is not quite as large as astronomers thought, according to the first measurements of its radius taken in more than 40 years.

Jupiter is a gas giant and doesn’t have a solid outer surface like Earth. But astronomers can still assess its shape by measuring how the height of its gas, for a certain pressure level, fluctuates around the planet, similar to measuring where sea level lies on Earth.

Our best measurements of this gas pressure level were taken by NASA’s Voyager and Pioneer spacecraft more than 40 years ago. The probes sent radio waves through Jupiter’s atmosphere towards Earth, where the data was then measured and the radio waves’ properties used to calculate the gas’ pressure at a given height, a technique called radio occultation.

Now, Eli Galanti at the Weizmann Institute of Science in Israel and his colleagues have measured Jupiter’s radius using radio occultation measurements from NASA’s Juno spacecraft, which has been in orbit around the gas giant since 2016. They found Jupiter is around 8 kilometres smaller on average than we thought, with the reduction more pronounced around its poles, which also makes the planet more squashed, or oblate.

“Based on the Juno radio occultations, we find that the size of Jupiter is smaller, more oblate, because at the equator, the change is about 4 kilometres smaller,” Galanti told the Europlanet Science Congress (EPSC) in Helsinki, Finland on 11 September.

Galanti and his team took 13 different radio occultations with Juno, compared to the six for Voyager and Pioneer combined, and then used known measurements of Jupiter’s wind speeds to calculate its diameter. For gas at 1 bar, which is the pressure of Earth’s atmosphere at sea level, the planet measured 142,976 kilometres across at its equator and 133,684 kilometres across at its poles.

“It’s not about just knowing exactly where the radius is, but it’s really about understanding its internal workings,” says Oded Aharonson at the Weizmann Institute of Science, who wasn’t involved in the analysis. “The planet’s interior is mysterious and otherwise hard to probe, so having these new constraints could help us build more accurate interior models.”

The world capital of astronomy: Chile

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Article amended on 15 September 2025

We have clarified the new equatorial and polar measurements

SPACE | SEP 11, 2025, 1:00 PM EDT | VIEW ON NEW SCIENTIST

A weird cloud forms on Mars each year and now we know why

Astronomers have struggled to explain why a long and thin cloud forms above Mars’s Arsia Mons volcano each year, until now

By Alex Wilkins

Unusual clouds form over the Martian volcano Arsia Mons each year

ESA/DLR/FU Berlin/J. Cowart CC BY-SA 3.0 IGO

A thin cloud that appears on Mars each year has baffled astronomers ever since it was first spotted, but it may be the result of a moisture-rich atmosphere that was thought impossible.

Each winter, an 1800-kilometre-long cloud forms near Mars’s Arsia Mons volcano in the south of the planet, appearing and disappearing every day for nearly three months. The conditions in Mars’s atmosphere are markedly different to Earth’s, such as containing many more small dust particles that can trigger water vapour in the air to condense into cloud particles. This produces many cloud patterns that we don’t see on Earth, but simulations that include these high dust levels in Martian atmospheres still can’t form the Arsia Mons cloud’s distinctive features.

Now, Jorge Hernández Bernal at Sorbonne University in France and his colleagues say they can reproduce the cloud’s features if there is an extremely high amount of water vapour in the air, something that was previously thought impossible in Mars’s atmosphere because of the high dust levels. These high water vapour levels help cloud particles form through an alternative, dust-free route called homogeneous nucleation.

When the researchers ran simulations of the atmosphere around Arsia Mons with much higher levels of water in the air, the resulting cloud looked strikingly similar to the real cloud, with a long tail stretching away from the volcano, which then spreads out to form what is known as an outburst.

“Homogeneous nucleation requires, in the case of Mars, a much higher level of [water] saturation. This is why, in principle, we thought that this was not possible on Mars, or was very unlikely,” Hernández Bernal told the Europlanet Science Congress (EPSC) in Helsinki, Finland on 10 September. “But in the last decade, we have learnt that there is, in fact, supersaturation on Mars.”

The world capital of astronomy: Chile

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SPACE | SEP 11, 2025, 6:00 AM EDT | VIEW ON NEW SCIENTIST

Deflecting a deadly asteroid just got a lot less dangerous

Our first attempt at shifting the orbit of an asteroid has provided crucial insight into how we could safely deflect a space rock that was hurtling towards Earth

By Alex Wilkins

Hitting an asteroid in the wrong place could accidentally make it more likely to impact Earth

buradaki/Shutterstock

If an asteroid was heading for a deadly impact with Earth, could we nudge it off course safely without making the situation worse? Yes, thanks to a new system for calculating the perfect spot to smack a spacecraft into an incoming asteroid.

Steering away an asteroid bound for Earth is a high-stakes endeavour, and we have not had much practice. In 2023, NASA’s Double Asteroid Redirection Test (DART) showed for the first time that we can divert a space rock by smashing a small probe into the tiny asteroid Dimorphos, which orbits a larger asteroid called Didymos, and changing its orbit by 30 minutes.

But such a manoeuvre is not without risk. Shifting an asteroid into a new orbit can in turn push it through a tiny window, called a gravitational keyhole, where the gravity from a larger body like Earth can change its orbital path enough to make it boomerang around and hit the planet at a later date.

Now, Rahil Makadia at the University of Illinois at Urbana-Champaign and his colleagues have developed a system to locate the perfect spot for a colliding satellite to minimise this risk. The team used data gathered from the DART mission, as well as information about an asteroid’s shape, mass and rotational speed, to predict how different impact locations change the asteroid’s path. This can be used to produce a probability map of an asteroid’s surface, with each point giving a different chance of pushing the object through a gravitational keyhole. Scientists can then pick the lowest probability impact site.

“Mapping these keyholes onto the asteroids is possible and all it costs before the mission even lifts off is computing power, so we should be doing this to make sure we can pick the best possible targeting point on the surface of the asteroid for any kinetic impact,” Makadia told the Europlanet Science Congress (EPSC) in Helsinki, Finland on 9 September.

Makadia and his team tested their method on the asteroid Bennu, identifying more than 2000 possible keyholes to produce a map of locations that could be safely hit with a spacecraft.

Gathering the specific information for one asteroid would be best done with a custom probe sent to gather information, but this might not always be feasible if the asteroid was discovered close to a potential Earth impact. However, a rough analysis should still be possible using information from telescopes on Earth, says Makadia.

Artist’s impression of NASA’s Double Asteroid Redirection Test mission

NASA/Johns Hopkins APL/Joshua Diaz

A safe test run for gathering this sort of data will be when the asteroid Apophis makes an extraordinarily close pass by Earth in 2029. Astronomers have calculated the 450-metre-long space rock will pose no risk to Earth, but an object of its mass passing so close to Earth is a 1-in-7500 year event, so astronomers are scrambling to get space missions ready to intercept the asteroid in under four years’ time.

“We’ve seen lots of asteroids, but we’ve never seen an asteroid undergo this kind of stress and natural vibrations from the gravitational force of the earth,” Richard Binzel at the Massachusetts Institute of Technology told EPSC on 8 September.

Both NASA’s OSIRIS-APEX spacecraft, which originally visited the asteroid Bennu but has now been redirected to visit Apophis, and the European Space Agency’s RAMSES spacecraft will hopefully be ready to view the asteroid as it passes by Earth.

As well as orbiting the asteroid at a safe distance and gathering key information like its composition and shape, astronomers also hope to land small kilogram-sized spacecraft on its surface to measure what is going on in its interior, including long-predicted seismic activity that happens when an asteroid passes near a large body like Earth.

Understanding these properties for a future Earth-threatening asteroid could be crucial, said Binzel. “If we had to deal with an actual asteroid threat, from Apophis or any object, we would certainly want to know these properties, like the spin or tumbling state [of an asteroid].”

Nudging Apophis off course won’t be necessary because its orbital path has been so well calculated by astronomers, and there is also no risk the RAMSES spacecraft could accidentally bump it into a dangerous orbit, says Paolo Martino, the mission’s project manager. The spacecraft has sensors that let it autonomously avoid a collision, and even if an impact did happen, its low mass means it would have little effect on Apophis, he says.

The world capital of astronomy: Chile

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Humans

- Early Neanderthals hunted ibex on steep mountain slopes (paid): 2025 Sep 11

- Britain's economy thrived after the withdrawal of the Roman Empire: 2025 Sep 11

HUMANS | SEP 11, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

Early Neanderthals hunted ibex on steep mountain slopes

Ancient remains from a cave in Serbia show that Neanderthals were hunting mountain goats 300,000 years ago, adding to evidence of their ability to adapt to different environments

By Christa Lesté-Lasserre

Ibex can move nimbly across steep mountain slopes

Serge Goujon/Shutterstock

Nearly 300,000 years ago, Neanderthals had already figured out how to hunt mountain goats along vertical cliffs and process them in well-organised camps.

Known for ambushing large animals in Western Europe’s flat meadows and forests, it seems Neanderthals adapted to the hills of Eastern Europe by adding nimble ibex to their hunting regime. The early humans skinned and butchered the animals in a nearby cave before roasting their bones for marrow and grease, showing impressive skill and knowledge far earlier than expected, says Stefan Milošević at the University of Belgrade in Serbia.

“The approach of hunting ibex is completely different, because it lives on a very rugged and steep, barren terrain,” he says. “We now see that early Neanderthals – who had barely differentiated themselves anthropologically as a species – were already exploiting ecological niches that no hominin had ever exploited before.”

Neanderthals evolved about 400,000 years ago, but most of what we know about them comes from sites in Western Europe that are younger than 150,000 years. So finding clues that fill in gaps in the Neanderthal timeline, habitat and culture is critical, says Marie-Hélène Moncel at France’s National Museum of Natural History in Paris, who wasn’t involved in the study.

In 2017, archaeologists found Neanderthal remains in an approximately 290,000-year-old layer of the Velika Balanica cave in Serbia, making them the oldest such remains found in Eastern Europe.

Since then, Milošević and his colleagues have discovered hundreds of stone tools and sifted through about 30,000 animal bone fragments in the cave. Nearly three-quarters of the fragments are slivers less than 2 centimetres long, and most of the identifiable ones are from ibex and red deer killed in spring and summer, suggesting the Neanderthals were seasonal cave dwellers.

Some bones – especially long deer legs – were burned and cracked open, meaning these early Neanderthals were probably heating bones to liquefy the marrow for easier extraction and leaving leftover fragments in the hearth so that bone grease would keep the fire burning. Others showed signs of tendon harvesting, possibly for rope or nets.

Deer skeletons represented older youngsters and adults, a sign of selective hunting that promotes herd survival, says Milošević. But the ibex were killed at all life stages – suggesting the Neanderthals were still “rookies” up against mountain goats, probably hunting with sharpened sticks and rudimentary traps. “They most likely had a lot of unsuccessful attempts,” he says.

In addition to these preferred food sources, the researchers also found a few processed remains from wild boar, cave bears, wolves, foxes, leopards and various birds.

The organised positions of the bones in different sections of the cave point to distinct zones for specialised tasks. The hearth was in the centre, for example, with discarded bones piled up behind it, and the entrance appeared to be used as a tool workshop.

Overall, the findings point to “remarkable cognitive flexibility,” says José Carrión at the University of Murcia in Spain. “It’s a confirmation that Neanderthals were creative problem-solvers, managing complex habitats with ingenuity and skill. Neanderthals were humans – intelligent, social, and extraordinarily adaptive.”

“What emerges from Balanica is the picture of Neanderthals who were not only resilient but already experimenting with strategies and social organisation that we tend to associate with much later periods,” says Antonio Rodríguez-Hidalgo at the Archaeological Institute of Mérida in Spain. “It reminds us that Neanderthal sophistication was not a late spark, but a deep-rooted flame that ignited surprisingly early in human history.”

Journal reference:

Quaternary Science Reviews DOI: 10.1016/j.quascirev.2025.109554

Neanderthals, ancient humans and cave art: France

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HUMANS | SEP 11, 2025, 6:00 AM EDT | VIEW ON NEW SCIENTIST

Britain's economy thrived after the withdrawal of the Roman Empire

An archaeological dig in northern England shows iron and lead processing continued and even increased after the departure of the Romans

By Michael Marshall

Archaeological excavations near Aldborough, UK, are helping us understand life after Roman occupation

R Ferraby & M.J. Millet

When the Roman Empire withdrew from Britain, the result was not chaos and economic collapse. The metals industry in what is now northern England continued and even expanded in the subsequent centuries, according to an archaeological record of pollution from metalworking.

“The argument has been that, with the disappearance of state apparatus and linked state transport systems, the regional economies collapse totally,” says Christopher Loveluck at the University of Nottingham in the UK. But that isn’t what the archaeology revealed. “We’re seeing an increase in metal pollution products.”

Loveluck is part of a team that has excavated Roman remains from Aldborough in North Yorkshire, England. Under Roman rule, this town was called Isurium Brigantum, where metals like iron and lead were mined and processed.

The team found aerosol pollution from these metalworking operations had become trapped in the silt accumulating in an ancient riverbed at the archaeological site. By digging through the layers of sediment, the team was able to reconstruct how pollution levels varied between 345 and 1779 AD.

“They get this long chronology, so you really can trace the ups and the downs,” says Jane Kershaw at the University of Oxford, who wasn’t involved in the research but who has studied early medieval metal mining.

In the late 300s and early 400s, the Roman Empire lost control of Britain and withdrew. “The government apparatus goes, the tax collection apparatus goes, no new coinage arrives in Britain, and they almost certainly withdraw all of the field army units as well,” Loveluck says. The subsequent centuries have few written records, and certain industries – notably wheel-thrown pottery – went into steep decline. This gave rise to a narrative of “the society of 5th century Britain just collapsing”, says Loveluck.

The riverbed record tells a different story. Lead pollution was low during Roman times, and fell only slightly in the late 300s and early 400s. It then rose steadily until the mid-500s. Likewise, pollution from ironworking rose during the first half of the 500s.

This, argues Loveluck, suggests continuity in the large-scale production of essential commodities.

The rise in metal production may have been due to internal fighting, suggests Kershaw. “It’s a period where the various Anglo-Saxon kingdoms are coalescing,” she says. “There’s a lot of fighting between those different kingdoms.” Many men were buried in graves with swords and knives.

Metal production then declined sharply in the mid-500s, and remained low for several decades. The team suggests this might be due to the Justinianic plague, which cut through the lands around the Mediterranean in 541-549 AD. Ancient DNA evidence from a graveyard in east England shows the plague did reach Britain. However, it is not clear how severe or widespread it was. “We don’t have grave pits full of plague victims, for instance, like we do with later plague events,” says Kershaw.

Anglo-Saxon coins dating from the 10th and 11th century

Andrew Cowie/Alamy

The apparent resilience of Aldborough metal production in the face of the Roman withdrawal fits with other evidence of economic and political continuity. “Droitwich in Worcestershire [in western England] has an unbroken sequence of salt production from the Roman period to the modern period,” says Loveluck.

The period after the Roman withdrawal has been dubbed the Dark Ages, due to a lack of written records and supposed intellectual decline. However, historians say that is at best an oversimplification.

Some practices did cease, like wheel-thrown pottery and building using stone. But this period also saw the production of spectacular metalwork, often using copper. “If everything was so terrible and dark, how come they’re wearing these amazing brooches and they’ve got colourful bead necklaces,” says Kershaw.

Journal reference:

Antiquity DOI: 10.15184/aqy.2025.10175

Walking Hadrian's Wall and Roman innovation: England

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Health

- In the race to reach 100, the wealthy have a head start: 2025 Sep 17

- Hedonistic habits could turn you into a mosquito magnet (paid): 2025 Sep 12

LEADER: HEALTH | SEP 17, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

In the race to reach 100, the wealthy have a head start

There are more centenarians now than ever before. But more must be done to address inequalities that prevent people from having a realistic chance of hitting this milestone.

By New Scientist

Getty Images For Unsplash+

Living to 100. It is a milestone that, until recently, was so rare that hitting it would secure you newspaper inches and perhaps a segment on local radio. Today, it is an ambition well within reach for many of us. Last week, Japan celebrated a record number of centenarians – now almost 100,000. Globally, nearly half a million centenarians were alive in 2015, more than four times as many as in 1990. This is projected to rise to 3.7 million by 2050.

Much of this is down to advances in medicine, as well as a better understanding of what the human body needs to function at its full potential. We also now know much more about what we can personally do to enhance our chances of hitting triple figures. In our special issue, you will learn how to eat, move and even think your way towards increasing the odds that you’ll be blowing out 100 candles on your birthday cake.

Even so, personal decisions can only take us so far, and the reality is that there is a widening gap in both lifespan and healthspan between rich and poor. In the UK, people living in the richest areas now experience close to 18 extra years in good health than those in poorer regions, representing a disparity increase of 22 per cent for men and 17 per cent for women over a decade. A recent Lancet report showed that the US life expectancy gap between the longest-living demographic – Asian Americans – and the shortest-living – Native Americans and Native Alaskans – grew from 12.6 years in 2000 to 20.4 years in 2021. In India, as in the rest of the world, the covid-19 pandemic fuelled a chasm between the most and the least advantaged. In 2020, high-caste Hindus saw a decline in life expectancy of 1.3 years, while Indian Muslims lost 5.4 years. Such numbers are unacceptable. Access to nutritious food, safe housing and inoculation from the grinding stress of poverty are needed to stem rising disparities.

“ Globally, the number of centenarians is expected to reach 3.7 million by 2050 “

In our optimisation mission, let us not forget to pressure politicians to address this growing inequality. Living to 100 must be an ambition we can all aspire to – not solely the preserve of the world’s wealthiest.

HEALTH | SEP 12, 2025, 9:00 AM EDT | VIEW ON NEW SCIENTIST

Hedonistic habits could turn you into a mosquito magnet

A study of festivalgoers suggests that drinking beer and sharing a bed makes you more attractive to mosquitoes

By James Woodford

Mosquitoes may not bite indiscriminately

hugh sturrock/Alamy

Hedonists who drink beer, don’t wash, share a bed and eschew sunscreen may be more attractive to mosquitoes – at least, that’s what a study of festivalgoers found.

For their Mosquito Magnet Trial, Sara Lynn Blanken at Radboud University Medical Centre in the Netherlands and her colleagues visited the 2023 Lowlands Festival, near Amsterdam. They asked 465 attendees to complete a questionnaire about their health, diet, hygiene, sunscreen application, any substance use, blood type and whether they had slept alone the night before.

The team also set up a makeshift laboratory in shipping containers, containing 1700 captive-reared mosquitoes (Anopheles stephensi), which can transmit malaria.

Between 20 and 35 mosquitoes were put into a series of clear plastic containers with a perforated divider separating the participants’ arms from the insects, so they could attempt to land on the revellers, but not actually bite them.

The researchers counted how many times the mosquitoes tried to land on the festivalgoers’ arms in three minutes compared with a decoy of cotton pads soaked in glucose.

“Mosquitoes showed a clear preference for the well-hydrated, on hops and grapes, that is,” according to the researchers. “Arm landings were significantly higher in beer drinkers compared [with] those who had nobly abstained for at least 12 hours.”

Blanken says she won’t let this put her off beer. “I would just wear long sleeves and insect repellent,” she says.

The researchers also found that the “participants that successfully lured a fellow human into their tent the previous night also proved more enticing to mosquitoes”. Sunscreen seemed to repel the mosquitoes, possibly by masking skin smell or acting as a repellent. The researchers found no evidence that different blood types attract or repel the pests.

“We found that mosquitoes are drawn to those who avoid sunscreen, drink beer and share their bed,” according to the team. “They simply have a taste for the hedonists among us.”

Festivalgoers put their arm through a partition where mosquitoes could try to land on them, but not actually do it

Lowlands festival/Nationale Wetenschapsagenda Netherlands

Cameron Webb at the University of Sydney says it’s a fun study that he wished he’d thought of, but it included only one species of mosquito, and the results would probably differ with other types.

The researchers also found that only four of the participants had zero attempted landings on their arms. “The biggest take-out message for me is that the vast majority of participants, irrespective of all the other factors considered, attracted mosquitoes looking for a blood meal,” says Webb. “The reality is that if we just reminded ourselves to put on mosquito repellent and spent less time thinking about why mosquitoes bite us, we’d all probably receive fewer bites and lower our risk of mosquito-borne disease.”

Reference:

bioRxiv DOI: 10.1101/2025.08.21.671470

Table of Contents

New Scientist: 2025 Sep 17

Features

How to nurture the right mindset for living to 100 (paid): 2025 Sep 16

The real scientific insights from Bryan Johnson’s immortality quest (paid): 2025 Sep 16

What’s the secret to living well beyond the average life expectancy? (paid): 2025 Sep 16

The science revealing how the right diet can add a decade to your life (paid): 2025 Sep 16

The exercises you need to do to reach 100 in great shape (paid): 2025 Sep 16

Why caring for your microbiome is crucial if you want to live to 100 (paid): 2025 Sep 16

What it’s like to run the world’s best dark matter detector (paid): 2025 Sep 15

News

Wild chimpanzees may get mildly intoxicated from alcoholic fruit: 2025 Sep 17

Dome-headed dinosaur from Mongolia is the oldest ever found: 2025 Sep 17

Stretching the skin could enable vaccines to be given without a needle: 2025 Sep 17

Global suicide rates fell 30 per cent since 1990 – but not in the US (paid): 2025 Sep 17

Asteroid exploded 'similar to a bomb' over France in a rare event (paid): 2025 Sep 17

30,000-year-old toolkit shows what ancient hunter carried in a pouch (paid): 2025 Sep 16

Long covid may be making your periods longer and heavier: 2025 Sep 16

Around one-third of AI search tool answers make unsupported claims (paid): 2025 Sep 16

Making atoms self-magnify reveals their quantum wave functions (paid): 2025 Sep 16

Good immune health may come at the expense of chronic inflammation: 2025 Sep 16

Lunar missions may contaminate the moon with hardy Earth microbes (paid): 2025 Sep 16

The oldest human mummies were slowly smoked 14,000 years ago: 2025 Sep 15

Modular nuclear reactors sound great, but won't be ready any time soon (paid): 2025 Sep 15

Mars once had an atmosphere that was thicker than Earth's today (paid): 2025 Sep 15

Covid-19 vaccine benefits worth up to $38 trillion in first year alone (paid): 2025 Sep 15

Stealth radio hides signal in background noise to protect drone pilots (paid): 2025 Sep 15

The death of dinosaurs dramatically re-engineered Earth's landscapes: 2025 Sep 15

Jaguar breaks records by swimming at least 1.3 kilometres (paid): 2025 Sep 12

Physics

Why simple tasks like charging your phone rely on quantum measurements (paid): 2025 Sep 11

Space

Jupiter is smaller and more squashed than we thought (paid): 2025 Sep 12

A weird cloud forms on Mars each year and now we know why (paid): 2025 Sep 11

Deflecting a deadly asteroid just got a lot less dangerous (paid): 2025 Sep 11

Humans

Early Neanderthals hunted ibex on steep mountain slopes (paid): 2025 Sep 11

Britain's economy thrived after the withdrawal of the Roman Empire: 2025 Sep 11

Health

In the race to reach 100, the wealthy have a head start: 2025 Sep 17

Hedonistic habits could turn you into a mosquito magnet (paid): 2025 Sep 12