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- 'Most of it is good': Tim Berners-Lee on the state of the web now (paid): 2025 Oct 29

- How a surge in ancient plagues 5000 years ago shaped humanity (paid): 2025 Oct 28

- No space, no time, no particles: A radical vision of quantum reality (paid): 2025 Oct 27

TECHNOLOGY | OCT 29, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

'Most of it is good': Tim Berners-Lee on the state of the web now

The man who invented the web is aware of the many issues it faces, from problematic social media use to the rise of unfettered AI. He also has a plan to remedy the situation

By Timothy Revell

Tim Berners-Lee in a rack of the CERN computer centre

Brice, Maximilien/CERN

Tim Berners-Lee has a map of everything on the internet. It can fit on a single page and consists of around 100 blocks connected by dozens of arrows. There are blocks for things like blogs, podcasts and group messages, but also more abstract concepts like creativity, collaboration and clickbait. It plots the lay of the digital landscape from a unique vantage point: the view of the man who invented the World Wide Web.

“Most of it is good,” he tells me, sitting in New Scientist’s London offices, as we discuss what has gone wrong and what has gone right with the web. He created the map to help show others – and perhaps also remind himself – that the parts of the internet judged as causing harm to society form only a small fraction of it. The top left quadrant makes it clear where Berners-Lee thinks the problem lies. Six blocks earn the label “harmful”. Written inside are the words: Facebook, Instagram, Snapchat, TikTok, X and YouTube.

Over the past 35 years or so, Berners-Lee has watched his invention go from a single user (himself) to 5.5 billion – about 70 per cent of the world’s population. It has revolutionised everything from how we communicate to how we shop. Modern life is unimaginable without it. But it also has a growing list of problems.

Misinformation, polarisation, election manipulation and problematic social media use have all become synonymous with the web. It is a far cry from the collaborative utopia Berners-Lee envisioned. As he writes in his new memoir, This Is For Everyone, “In the early days of the web, delight and surprise were everywhere, but today online life is as likely to induce anxiety as joy.”

It would be totally understandable if the web’s inventor were a bit sour about what humanity has done with his life’s work, but he is far from it. In fact, Berners-Lee is extraordinarily optimistic about the future, and the future of the web. As one of the most influential technological thinkers of our time (with a long list of awards and a knighthood to prove it), he has plenty to say about what’s gone wrong – and most importantly, how he hopes to fix it.

Inventing the web

The origin story of the World Wide Web is partly about being in the right place at the right time. In the late 1980s, Berners-Lee was working in the Computing and Networks division at CERN, the particle physics lab near Geneva, Switzerland, and he was wondering whether there was a better way to manage all the documentation.

Most systems forced users to follow particular rules for how documents should be organised, imposing strict hierarchies and relationships. Berners-Lee thought it would be better to let people connect documents in any way they liked. Hyperlinks already existed for linking things together within documents, and the internet already existed as a way to share files, so why not put the two together? This simple, yet groundbreaking idea became the World Wide Web.

The idea existed for some time in Berners-Lee’s head before, in 1989, he eventually convinced a sympathetic boss to let him pursue it full-time. In a matter of months, he produced a burst of acronymic activity that spawned HTML, a programming language for building web pages; HTTP, a protocol for sending them; and URLs, a way to locate them. Just 9555 lines of code in total. By the time the year was out, the web was born.

“CERN was a really great place to invent the web,” he says. “It has people from all over the world who have this desperate need to communicate and to document their lives and their systems.”

The first website, which was hosted on Berners-Lee’s work computer with a do-not-turn-off sign stuck to the front, outlined what the web was and how to join in. A few web servers sprang up, then a few more. “It went up by a factor of 10 in the first year, and then it went up by a factor of 10 the second year. And then in the third year [it] went up by a factor of 10 again”, he says. “Even back then, you could see that we were onto something. You had to buckle up and hold on.”

Most of the early web pages were made by academics and software developers, but people soon started to use them to put everything and anything on the internet. Within a decade, there were millions of websites, hundreds of millions of users and enough internet companies to fill a dot-com stock market bubble.

The Spice Girls pose with the band’s website in 1997

David Corio/Redferns/Getty Images

Despite the huge money-spinning opportunities of the web, Berners-Lee felt that for it to reach its true potential, it needed to be free and open. But that was easier said than done. As he had developed the software underpinning the web while at CERN, the organisation had a legitimate claim to charge royalties to anyone who used it. Berners-Lee turned to his superiors and pleaded the case that the technology should be donated to the world. It took a while to find someone who could actually sign off on such a thing, but in 1993, the full source code of the web was published along with the disclaimer, “CERN relinquishes all intellectual property rights to this code.” The web would be royalty-free forever.

The early days

For the first few decades of its life, the web seemed to be going pretty well. Yes, there was the infamous turn-of-the-millennium stock market crash, though this was arguably the fault of venture capital speculation rather than the web, per se. Pirating was certainly on the rise and malware seemed to be just one bad click away, but it was largely free, open and fun. “People loved the web so much. They were just delighted,” writes Berners-Lee in his memoir.

Capturing the mood of the time, he believed that the web could unlock a completely new form of human collaboration. He coined the term “intercreativity” to describe a group, rather than an individual, becoming a creative entity. Wikipedia, with its nearly 65 million English-language pages written and edited by 15 million people, epitomises what he had in mind. The site takes pride of place in his map and he describes it as “probably the best single example” of what he wanted the web to be.

Of course, this age of unfettered web optimism didn’t last forever. For Berners-Lee, it was 2016 when he began to feel like something was fundamentally wrong. “There was the Brexit election and the first Trump election,” he says. “At that point, people started to say it is possible that people have been manipulated using social media into voting for something that is not in their best interest. In other words, the web was part of a powerful manipulation of individuals by large organisations.”

Historically, political campaigns would “broadcast” their messages to voters out in the open, where everything could be seen – and, crucially, criticised. However, by the mid-2010s, social media had made it possible to “narrowcast”, as Berners-Lee puts it. Political messages could be turned into a thousand variations, each targeted at a different group. Keeping track of who was saying what and to whom became much harder. So too did countering misleading claims.

Link to video: https://www.youtube.com/watch?v=XLA-Kc5kEVc

How much this kind of microtargeting affects elections is still up for debate. Many studies have attempted to quantify how people’s views and voting intentions change when they see such messages, but the studies have generally found only small effects. Either way, it plays into a bigger concern that Berners-Lee has around social media.

He says social media companies have an incentive to keep your attention, which drives them to build “addictive” algorithms. “It’s human nature to be attracted by things that make you angry,” he says. “If social media feeds you something which is untrue, you’re more likely to click on it. You’re more likely to stay on the platform.”

He cites author Yuval Noah Harari, who has argued that people who make “bad” algorithms should be held accountable for their recommendations. “You have to specifically outlaw addictive systems,” says Berners-Lee. However, he recognises that a ban isn’t exactly in line with his usual free-and-open approach. It is a choice of last resort. Social media can connect people and spread ideas, but it also has a particular problem in causing harm, he writes in the new book: “We need to change that, one way or another.”

Still, he remains positive about where the web could be heading. Social media is just a small part of the internet map – even if it does draw a lot of our attention. Fixing it should be part of efforts to improve the web at large, and key to that is reclaiming digital sovereignty, he says.

A plan to make the web work for everyone

To that end, for the past decade, Berners-Lee has been working towards a new approach that hands the initiative back to individuals. Currently, different internet platforms control your data. You can’t easily post a Snapchat video you have made to your Facebook feed or a LinkedIn post to your Instagram account, for example. You have created those posts, but the respective companies own them.

Berners-Lee’s idea is that, rather than being spread between different platforms and companies, your data would sit in a single data wallet that you control, called a pod (short for “personal online data store”). Everything from family photos to medical records could live there, and it is up to you to decide if you want to share any of it. This isn’t just theoretical; he has co-founded a company called Inrupt to try to make this approach a reality.

Berners-Lee in 1994, with an early form of the websites and web browsers that he invented at CERN

CERN

He is particularly excited about the potential for data wallets to combine with artificial intelligence. He gives the example of trying to buy a pair of running shoes. If you used any of the current AI chatbots, you would have to spend time explaining what you were looking for before they could make a decent recommendation. But if an AI had access to your data wallet, it would already know all your measurements and your entire workout history – and perhaps your spending history, too – so it could precisely match your profile with the right shoe.

The AI should work for you, not big tech, says Berners-Lee. This isn’t about building your own AI, but about having guarantees baked into the software. Data wallets are one part of that, although he also says that AIs should be signed up to a sort of digital Hippocratic oath to do no harm. It should be like “your own personal assistant”, he says.

A better running shoe recommendation isn’t exactly earth-shattering and is unlikely to fix many of the internet’s sharpest problems, but Berners-Lee’s greatest talent isn’t to imagine exactly how people will use something, but to see the potential of it before others can. Data wallets seem dry and esoteric now, but so too did a hyperlink-based document-management system just a few decades ago. Berners-Lee says he is driven by a desire to build a better world. An improved data ecosystem is the best way he sees to do that.

This all hints at what he thinks is next for the web. He wants to see us move away from an “attention economy”, where everything is vying for our clicks, to an “intention economy”, where we indicate what we want to do and then companies and AIs vie to help us do it. “It’s more empowering for the individual,” he says.

Such a change would dramatically shift power away from the big tech companies and back to users. Given that the internet has been moving in only the other direction of late, only a particular kind of optimist could believe that a reversal is just around the corner. The hold of big tech on our lives and the era of doomscrolling seem unlikely to end anytime soon. But then again, Berners-Lee has a track record of seeing things others can’t – and he is the one holding the map, after all.

HUMANS | OCT 28, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

How a surge in ancient plagues 5000 years ago shaped humanity

Plague, leprosy, smallpox and other diseases didn't jump from animals to humans when we thought. Ancient DNA is revealing where they come from and how they changed history

By Laura Spinney

Simon Pemberton

Disease historians have a problem. While examining samples of ancient human DNA, geneticists have come across genes belonging to the plague bacterium, Yersinia pestis, revealing that it ravaged Eurasia 5000 years ago. That’s nearly 3500 years before the “first plague”, also known as the Justinian plague, after the Roman emperor of the day. What to call this newly discovered prequel?

The current favourite, the Late Neolithic-Bronze Age (LNBA) plague, is a bit of a mouthful. But the scientists have more to worry about. Their chance discovery is another nail in the coffin of a long-held idea about when and why humanity acquired many of the contagious diseases that now afflict us. Of late, they have uncovered a rogue’s gallery of prehistoric horrors in samples taken from ancient humans. These so-called zoonotic diseases bothered animals before they bothered people, so were thought to have jumped the species barrier after humans invented agriculture, around 12,000 years ago. But as geneticists can peer further back into the past, they are finding that in many cases the leap occurred much later – with major outbreaks happening in Europe, you’ve guessed it, around 5000 years ago.

As well as upending old ideas about disease evolution, the discovery has forced a rethink of a pivotal period in prehistory. How were diseases spreading at that time? Did the pathogens have the same effects as they do now? And might plague itself have ushered in the Bronze Age, laying the foundations of European civilisation? It’s exciting stuff, says archaeogeneticist Megan Michel at Harvard University, given that a decade ago, “we didn’t even know this plague existed”.

The reconstruction of ancient disease landscapes has been a huge collaborative effort, but a group at the University of Copenhagen in Denmark has had a leading role. They began routinely screening ancient human remains for known pathogens about 15 years ago, having unexpectedly found microbial DNA in human samples. Armed with radiocarbon dates and information about how people in prehistoric cemeteries were related to each other, they could start to build a picture of the cultural and economic context in which the diseases spread. They could also track the evolution of pathogens over time – and investigate how the human immune system adapted in turn.

This approach has generated a quickfire sequence of important findings, including the discovery of pathogens that cause typhoid, hepatitis B, syphilis and smallpox in historical human populations – and culminated this July in the publication of a study led by population geneticist Martin Sikora, a member of the Copenhagen group. His team re-analysed around 1300 human samples spanning more than 35,000 years in Eurasia. All the DNA came from teeth, which preserve blood-borne pathogens because they have their own blood supply in life. Among the pathogens the researchers found were Y. pestis and the bacteria that cause leprosy and leptospirosis, or Weil’s disease. To their surprise, nearly 3 per cent of samples tested positive for another pathogen, Borrelia recurrentis, the causative agent of the now-rare relapsing fever – a relative of Lyme disease characterised, as its name would suggest, by recurring fever and blinding headaches.

The team also looked at trends over time. These revealed that until about 6500 years ago, the vast majority of microbes in the teeth of Eurasians belonged to the oral microbiome – the diverse, usually harmless or even beneficial community of organisms that inhabits the mouth. The first zoonotic pathogens, including plague, became detectable at that date, but only at very low levels. It wasn’t until around 5000 years ago that there was a spike in infections from Y. pestis and other major pathogens.

Arrival of the Yamnaya

This also happens to be the date that nomadic herders called the Yamnaya began arriving in Europe from the steppe, a vast expanse of grasslands and savannas spread across much of Eurasia, bringing new ideas and new languages. Coincidence? The researchers think not. Those herders had an exceptionally high burden of infectious disease. It isn’t clear why, but it was probably linked to their lifestyle. They kept much larger herds than static farmers – of sheep, goats, horses and cattle – and they lived with their animals around the clock. Their diet consisted mainly of meat and milk. “A lot of zoonoses can be transmitted through undercooked meat, but also through milk: brucellosis, listeriosis, bovine tuberculosis, to name just a few,” says infectious disease expert Astrid Iversen at the University of Oxford.

Plague doctors treated victims of bubonic plague during outbreaks in Europe

Science History Images/Alamy

Other findings appear to corroborate this hunch. For instance, by tracing how the genome of plague bacteria changed over time, archaeogeneticist Pooja Swali at University College London has been able to show that 4000-year-old cases of plague – which were the oldest known in Britain when she documented them in 2023 – were caused by strains related to those carried earlier out of the steppe. She could effectively see the disease moving from east to west.

Then there is relapsing fever. Earlier this year, Swali reported that B. recurrentis became specialised to humans in a window centring on 5000 years ago. Before that, the bacterium infected a range of mammals via the tick, its intermediate host, but then it swapped this out for the human body louse. Swali speculates this had to do with wool clothing, another innovation – besides metal tools – brought to Europe by the steppe nomads. B. recurrentis underwent a major reduction of its genome at that time, which could reflect adaptation to a new host – one that flourished in wool garments. “Maybe this massive reduction in genome meant that it became trapped in lice,” she says.

Meanwhile, French researchers have shown that the immune system of Europeans began adapting to infectious diseases like these around 6000 years ago, with the bulk of immunity-related genetic variants appearing around 4500 years ago. “All these pieces fit really nicely together,” says Sikora.

But there’s one piece that doesn’t fit so well. Sikora’s July paper cites two cases of plague in Orkney, off the north coast of Scotland, that predate the arrival of people with steppe ancestry in Britain by at least 500 years. What’s more, last year, another member of the Copenhagen group, Frederik Seersholm, described three outbreaks of plague over six generations of Neolithic Swedish farmers that occurred around 5000 years ago. Those farmers carried no steppe ancestry, indicating that they had yet to interbreed with – perhaps even to meet – these populations of eastern origin. A new study from Seersholm and Ruairidh Macleod at UCL, which has yet to be peer-reviewed, describes the oldest instances of plague in the world recorded to date, from around 3500 BC, which proved fatal to hunter-gatherers living near Siberia’s Lake Baikal, east of the Yamnaya’s point of departure towards the west.

Such cases have persuaded most people that plague was geographically widespread before the nomads arrived. One idea is that the LNBA plague got its foothold in the mega-settlements of the Trypillia culture of present-day Ukraine, beginning around 6000 years ago, and then spread through trade networks. Archaeogeneticist Nicolás Rascovan at the Pasteur Institute in Paris, who suggested this possibility in 2019, says his hypothesis remains on the table, though he admits it is difficult to test because almost no Trypillian burials have been found. Others are sceptical. A team led by anthropologist Alex Bentley at the University of Tennessee, Knoxville, has shown that the clustered layout of Trypillian megasites could have introduced effective firebreaks to contagion. Besides, the Baikal cases indicate plague was a problem for hunter-gatherers from an early date.

Plague without the fleas

What the disease was like back then is also unclear, but there is no doubt it could kill. “Whether it was as highly transmissible as the Black Death, I’d be more cautious,” says Sikora. It is unethical to try to revive ancient plague strains in the lab, but you can get a rough idea by comparing ancient plague genomes with later strains that have known clinical outcomes. Such analysis has revealed that LNBA strains lacked a genetic variant that allowed the bacterium to survive in the flea gut, leading researchers to conclude that they probably weren’t transmitted by flea bites, as the Black Death was in the 14th century.

Human body lice proliferated around 5000 years ago and became a vector for relapsing fever

MARTIN OEGGERLI/SCIENCE PHOTO LIBRARY

There are many other ways plague could have spread in the Late Neolithic, though. Macleod and Seersholm suggest it was airborne and spread through coughing. But we can’t assume it was capable of human-to-human transmission. Another possibility is that outbreaks were caused by people sharing feasts of undercooked, infected meat – in which case, each outbreak was an animal-to-human spillover event that probably fizzled out quickly. Plague has many animal reservoirs, including sheep, dogs and rodents, and researchers know very little about how prevalent it was in other species in the Late Neolithic, or how it evolved in them. “What’s missing is this huge piece of the puzzle – the animals,” says Swali.

Amid all the uncertainty, arguably the most burning question is whether the plague caused the so-called Neolithic decline, a dramatic fall in the population of western Eurasia. If so, it might also have ushered in the Bronze Age in that part of the world, a cultural revolution that introduced a more hierarchical and warlike social model – perhaps by clearing the way for those nomadic steppe herders who organised themselves in that way.

The Neolithic decline

Neolithic farmers lived in denser, more permanent settlements than herders or hunter-gatherers, and lots of people living in proximity certainly lend themselves to contagion. Seersholm thinks his study of Swedish farmers supports the idea that plague caused their decline. However, archaeological evidence – the thinning of the farmers’ cultural footprint, signs of violence and the regrowth of forests – suggests it began around 7000 years ago, 500 years before the first zoonoses appeared in Europe. “I retain my scepticism that plague is responsible for this population downturn,” says archaeologist Stephen Shennan at UCL. He thinks the root cause was an agricultural crisis – shrinking crop yields related to a cooling climate. Nevertheless, he says he might have to change his mind if earlier plague cases come to light.

That is possible. Geneticists are confident that the prehistoric prevalence of infectious disease was much higher than is detectable, in part because a disease can kill without showing up in the patient’s blood. This is the case for tuberculosis, for example, but also for the pneumonic form of plague, which infects the lungs. RNA viruses such as flu and coronaviruses aren’t yet detectable, either. Researchers are already searching for more evidence that Neolithic communities cratered as a direct consequence of plague. And one of them, archaeologist Kristian Kristiansen at the University of Copenhagen, thinks they will find it.

Whether or not the LNBA plague caused the decline, it could have exacerbated it – especially after the arrival of the Yamnaya. Kristiansen doubts that their expansion into Europe was driven by plague – he prefers the theory that population growth forced them to go in search of new pastures. But, he says, they might have picked up plague en route, to which their lifestyle offered them at least partial immunity, and then spread those strains far and wide. Their contact networks extended much further than those of farmers. “You can see it clearly in the human DNA,” says bioarchaeologist Thomas Booth at London’s Francis Crick Institute. “Suddenly, after 3000 BC, there are biological ties stretching right across Eurasia where previously they had been more confined to smaller regional clusters.”

And, of course, plague wasn’t the only disease to have a major impact. “One of the big takeaways for me, from the Sikora paper, is that around 10 per cent of the tested remains had positive evidence for a major infection at time of death,” says one co-author, evolutionary biologist Evan Irving-Pease at the University of Copenhagen. “The level of evolutionary pressure that would have exerted on ancient human populations is really quite substantial.” He and others believe that, in today’s more hygienic environment, variants of genes that were selected because they protected our ancestors from zoonotic disease predispose us to a different threat – autoimmune diseases such as multiple sclerosis (MS).

Yamnaya steppe nomads spread across Europe at just the time when animal-borne diseases proliferated

Piotr Włodarczak

Last year, with William Barrie at the University of Cambridge and others, Irving-Pease reported that a major genetic risk factor for MS tracks with steppe ancestry in Europe, being highest in the north of the region and lowest in the south. MS can be triggered by infection with the common Epstein-Barr virus today, but a different dangerous pathogen, prevalent in the Bronze Age, might initially have driven selection for that risk factor. Irving-Pease doesn’t know what it was, but with Iversen and others, he is hot on its trail.

And the Late Neolithic disease surge may have shaped more than the immune system. Before then, Europeans didn’t practise dairying and were mostly lactose intolerant – unable to digest the sugar in milk. One surprising discovery is that the Yamnaya were, too: they probably consumed milk in fermented form – as yoghurt, kefir or cheese – and unwittingly recruited free-living bacteria to digest the lactose for them. So they didn’t bring Europeans the genes that allow us to do this for ourselves. Instead, research hints, these variants may have increased in frequency when bouts of disease and associated famines forced Neolithic farmers to drink milk to survive.

Disentangling these complex biological and cultural interactions has implications for the future. Researchers may be close to uncovering the origins of MS, for example, but they can’t yet explain why it is becoming more prevalent over time. And zoonoses continue to pose a threat, accounting for an estimated three-quarters of emerging human diseases, including covid-19 – often because of our industrial-scale farming practices, destruction of forests and alteration of the climate. Understanding how they shaped us in the past will help us predict what lies ahead – and, potentially, to intervene with the powerful tools of modern medicine.

For the moment, though, it is the prospect of shedding light on our past that excites researchers most. “We can start to ask more interesting questions about the role of pathogens in human prehistory,” says Michel. Infectious disease has been called “the loudest silence in the archaeological record”. Finally, we are dialing up the volume.

PHYSICS | OCT 27, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

No space, no time, no particles: A radical vision of quantum reality

If we admit that quantum numbers are the true essence of reality – not particles, space or time – then a surprising and beautiful new vision of reality opens up to us

By Vlatko Vedral

Skizzomat

Many have pinpointed the birth of quantum mechanics to the small, treeless island of Helgoland, where a young Werner Heisenberg went in the summer of 1925. There, he sketched out the basics of what would become our most brilliant and successful way of explaining reality. At the heart of his approach was the decision to focus exclusively on what observers would find when they measured particles.

It was a flash of genius – but it has also tied physicists up in knots for 100 years. Much of the trouble comes down to questions about what an observer is and what exactly constitutes an observation. Are we to believe that reality is somehow contingent on us looking at it?

I believe it is now time to move on from this metaphysical mess. I have thought about quantum theory for much of my career and I have come to believe we don’t need observers – it makes no sense to talk about them. There is a much more consistent and reasonable way to describe the quantum world that I would like to share with you now, together with the three clinching experiments that can prove my case.

While this framework, in my opinion, makes a lot of logical sense, it takes us into unfamiliar territory. It’s not just observers that don’t exist – there are no particles either. And space and time? Well, we will get to them. These are deep waters, to be sure, but it is worth wading in because, as we do so, we find clues to what might lie beyond quantum theory as we know it.

To begin with, let’s take a whistle-stop tour of modern physics and the spider’s web of problems it creates. Observers were a key tenet of physics long before quantum mechanics: indeed, they played a crucial role in Albert Einstein’s development of both special and general relativity. The latter theory says that space and time are melded together in the fabric of space-time, and it is the bending of this fabric that creates gravity. I will challenge this view later, but one implication of the original idea is that observers in places where the curvature of space-time is different will experience time passing at different relative speeds.

When we teach relativity, we often talk about observers in this way, imagining them as people. But the truth is that the time experienced by any moving object (even, say, an atom) will change with respect to objects in differing gravitational fields. These differences needn’t be recorded by observation, so we don’t need a special category of “observers”.

Teachers of physics often talk about “observers”, but they may ultimately be a misleading concept

Titipong Makkarach/Getty Images

General relativity is the first of the two pillars of modern physics, the other being quantum theory itself. The essence of the theory is that reality is divided into discrete chunks at the most fundamental level. For example, when atoms take in or spit out energy, it happens in packets of a certain size, not continuously. But observers are baked into quantum theory too, because it distinguishes between particles before and after “observation”. Beforehand, we describe them using the wave function, an equation that sets out a range of possible properties – a superposition. Afterwards, this is said to “collapse” into a specific value.

The trouble is, this gives rise to all sorts of questions, the most basic of which is how and why collapse happens. It also creates paradoxes, such as Wigner’s friend, dreamed up decades ago by physicist Eugene Wigner. He imagined a “friend” inside a sealed lab making a quantum measurement while he himself waited outside. The problem comes when we compare the two people’s descriptions of reality. Wigner hasn’t observed anything, so the whole lab is described by the fuzzy wave function. Yet, for his friend, there is a definite outcome. With this paradox, Wigner was asking how we know when an observation becomes definitive.

Some physicists think we need to tweak quantum theory to deal with all this. But not me. To explain how I think about it, we need to grasp the phenomenon of entanglement, which Erwin Schrödinger called quantum theory’s “characteristic trait”. Quantum entanglement is often seen as mysterious, but it is really just a special link between two quantum objects such that when you measure one, you immediately know something about the other’s properties. Here’s the key point: when we talk about “observations”, what we are really referring to, in my opinion, is the moment two systems become entangled with each other. Although the thing that gets entangled can be a person – an “observer” – it doesn’t have to be.

Let me give you an example. There is a famous experiment in which a particle of light, or photon, in superposition goes through two slits in a screen at the same time, creating an interference pattern when it hits a second screen. But if we observe which slit the photon goes through, then no interference takes place. Before you conclude that our observation collapses the superposition, bear in mind that if we entangle anything else with the photon in a way that reveals which slit it takes, we get the same effect.

So we should stop talking about “observers” and instead talk about entanglement. By the way, this view dissolves the question Wigner raised with his paradox, too. There is no “ultimate” observer – there are no observers at all. What really happens is that the system and observer (just another system) become entangled.

What I would like you to take from all this is that quantum theory already contains everything we require to understand reality. We only need to take its full implications seriously – even if they appear strange. So, let us now explore where that takes us, starting with a central idea in physics: particles.

The unreality of particles

To grapple with this concept, the first things we need to deal with are fields. A field is an entity that exists everywhere and changes over time, an idea originally introduced by Michael Faraday in the first half of the 19th century. In classical electromagnetic field theory, the electric and magnetic field values are ordinary (or classical) numbers called c-numbers, as in 5 metres. Each point in space has three electric field numbers and three magnetic field numbers assigned to it.

In quantum theory, we instead talk about quantum fields where every point in space is described not by single numbers, but instead tables of numbers. These tables are called quantum numbers or q-numbers. This is why many people take Heisenberg’s 1925 paper as the beginning of quantum physics: he was the first to propose upgrading the positions and momenta of particles to q-numbers. This difference between c-numbers and q-numbers is simple but profound – we will come back to it later.

However, not everyone is prepared to take seriously the full implications of quantum fields. When physicists took the classical electromagnetic field and quantised it, this implied the field could oscillate in more modes than was previously possible. In the quantum field, there are four of these modes and the theory predicts that the field should be able to manifest as particles, in this case photons, in each one. But here’s the weird thing: we can only ever detect photons in two of these modes. The other two cancel out and aren’t detectable, even in principle. These “ghost” photons are therefore unobservable yet unavoidable.

Philosophically troubling? Perhaps. But this isn’t unusual. Much of science works this way. We postulate things because the explanatory power of a theory would fall apart without them.

I don’t think we should sweep these oddities under the table, but should embrace them. Chiara Marletto, my colleague at the University of Oxford, and I have suggested that even though these ghosts can’t be directly detected, they should get entangled with electrons under certain circumstances and this entanglement could, in principle, be detected. As we set out in a 2023 paper, you could do this by putting an electron into a superposition, whereupon, if we are right, it should get entangled with the ghosts, and this would be detectable with the right kind of careful measurement. It is a challenging experiment, but certainly one that lies within the reach of existing technology. It would be a quantum equivalent of seeing a ghost.

Vlatko Vedral working on an entanglement experiment in the lab

Sunny Tiwari

What would it mean if this experiment showed that these ghosts can be entangled, as I fully expect it would? The most basic thing we normally think of as capable of being entangled is a particle. But ghosts can’t truly be considered particles. All they are, in truth, is q-numbers in an equation. But that, for me, is precisely the point. It is the q-numbers that are fundamental, not the human conception of a “particle”. It just so happens that particles have q-numbers, and that has misled us into thinking the former are the fundamental elements of reality, when it is actually the latter.

There is another layer of sophistication that reinforces my argument that particles aren’t real. Let’s consider an individual particle, say an electron. In the language of vanilla quantum theory, we would say that, before we measure this particle, it is in a superposition of states. It is both here and there, and both possibilities are described by q-numbers. But now change your perspective. If q-numbers are the essence of reality, these two q-numbers can be entangled with each other. Put another way, you might say that a particle in superposition can be “entangled with itself”.

Not all physicists would accept this is possible, but more than 15 years ago, I proposed an experiment that can determine the truth, this time with my colleague Jacob Dunningham, now at the University of Sussex, UK. Take a single particle and make its state delocalised, so that it is in a superposition of two different physical locations. To experimentally verify whether the superposition is entangled, you need to make separate measurements in the two different locations and check if they violate an equation called Bell’s inequality, the hallmark of entanglement.

There is already some evidence that this single-particle entanglement occurs. Experiments conducted by Björn Hessmo at the KTH Royal Institute of Technology in Sweden and his colleagues in 2004 showed that individual photons split between two positions do violate Bell’s inequality. Photons, in other words, aren’t fundamental elements of reality – it is their q-numbers that matter. Still, photons are massless and no one has yet done this with an object with mass, such as an atom or even a much lighter electron, because those experiments are challenging. But there is no doubt in my mind that the outcome would be the same.

Are space and time real?

Now we are ready to talk about space and time. Some people think of this as the last frontier of physics, and it is related to the field’s biggest open problem, namely that of combining those two pillars of physics, general relativity and quantum theory, into a theory of quantum gravity. Since I have so far argued that we should think of everything as being made up of q-numbers, you might anticipate that space and time should be quantum too. Indeed, many researchers think this.

But here I take a more radical view: space and time don’t exist at all. Like “observers”, they are convenient labels – bookkeeping devices – but there are no physical entities corresponding to them. Therefore, quantising gravity doesn’t mean quantising space-time, it means quantising the gravitational field (upgrading Einstein’s c-numbers into q-numbers) in the same way that other fields are quantised.

“ I take a more radical view: space and time don’t exist at all “

This might seem a subtle point. After all, in general relativity, the gravitational field is thought of as being nothing more and nothing less than bending space-time. But this is where I put a twist on things: what bends isn’t space or time, but fields like the electromagnetic field that holds all matter together. Atoms, molecules, clocks and rulers are all bound by electromagnetism. The job of the gravitational field is to couple to these fields and tell them how to bend. For convenience, we talk about these fields being laid across an invisible grid we call space-time. That’s fine, but let’s not fool ourselves into thinking space-time is fundamental.

Some of my colleagues may consider this pretty extreme, and I admit it is hard to think of any experiment at present that could prove I am right. But for me, this is all part of taking quantum theory at face value. I am suggesting that gravity should be just like any other quantum field.

Along with space, time and observers, it seems that particles may not be a fundamental ingredient of reality

Pete Godfrey/Unsplash

So: no particles, no space, no time. Instead, I think the basic ingredient of nature is the q-number. To finish, let’s explore how fully embracing this principle might lead us towards new insights. What I am about to say brings to mind the story of when philosopher Bertrand Russell had a cosmology lecture interrupted by an attendee who claimed that the universe is carried on the back of a gigantic cosmic turtle. When Russell asked her what the turtle stands on, she replied: “It’s turtles all the way down!” My proposal is similar, although no turtles are involved.

When we talk about how quantum fields interact, we use a piece of mathematics called the quantum Hamiltonian. It has long bothered me that these Hamiltonians mix q-numbers with ordinary c-numbers – for example, physical constants such as the speed of light or the electron charge. This is routine, but it doesn’t seem right to me. Over the past century or so, physicists took classical equations and made some bits of them quantum. But wouldn’t it be neater, and in the spirit of the philosophy I have been espousing, if our equations were quantum through and through?

I’m not the first to think like this. In the 1980s, physicist David Deutsch proposed eliminating c-numbers altogether, making all the quantities in quantum Hamiltonians into q-numbers. Doing this, however, would have strange consequences. Let’s take just one of the possibilities and look at the speed of light, which we currently treat as a simple c-number. If we turned this into a q-number – which, remember, always describes a point in a quantum field – this would imply that there is some new quantum field connected to the speed of light. It would be a bit like what happened when we quantised the electromagnetic field and got those pesky ghosts, a suggestion that there is more to reality than we thought.

This general idea can be subjected to experiment. If there are extra quantum fields out there, particles should be capable of becoming entangled with them. Imagine, for example, you maximally entangle an atom and a photon. If there is another field out there that mediates this interaction, it should join the party and create a three-body entangled system. The result would be that the strength of the entanglement between the photon and the atom would be weaker than expected. In 2022, Jim Franson at the University of Maryland, Baltimore County, proposed one method for detecting this entanglement – it is conceptually quite similar to the experiment I imagined for detecting the ghosts. No one has performed this so far, but it is technologically possible.

In principle, we could imagine taking quantisation to an even deeper level. Q-numbers are tables of numbers, and you could easily “upgrade” all of the ordinary numbers in those tables to be q-numbers themselves – and then do the same again. Tables of tables of tables. In this view, it isn’t turtles, but rather q-numbers, all the way down.

Philosophers hate infinite regress. But nature is under no obligation to respect our philosophical scruples. The universe may simply be a bottomless pit, offering physicists an inexhaustible supply of mysteries.

News

- Quantum computers reveal that the wave function is a real thing (paid): 2025 Oct 31

- The gut microbiome may play a role in shaping our personality (paid): 2025 Oct 31

- Denisovans may have interbred with mysterious group of ancient humans (paid): 2025 Oct 31

- Bulletproof fabric laced with carbon nanotubes is stronger than Kevlar (paid): 2025 Oct 31

- Your flight emissions are way higher than carbon calculators suggest: 2025 Oct 31

- Magnetic gel could remove kidney stones more effectively (paid): 2025 Oct 30

- Boy's body was mummified and turned green by a copper coffin (paid): 2025 Oct 31

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- Dinosaur skeleton settles long debate over 'tiny T. rex' fossils: 2025 Oct 30

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PHYSICS | OCT 31, 2025, 1:00 PM EDT | VIEW ON NEW SCIENTIST

Quantum computers reveal that the wave function is a real thing

The uncertainty inherent to quantum mechanics has long left physicists wondering whether the observations we make on the quantum level reflect reality - a new test suggests they do

By Alex Wilkins

The wave function of a quantum object may not just be a mathematical construct

Pobytov/Getty Images

Does quantum mechanics really reflect nature in its truest form, or is it just our imprecise way of describing the weird properties of the very small? A famous test that can help answer this question has now been tried on a quantum computer, and it comes to a surprisingly concrete conclusion. Quantum mechanics really does describe reality completely, at least for tiny quantum devices – and the results could help us build better and more reliable quantum machines.

Since quantum mechanics was first discovered more than a century ago, its uncertain and probabilistic nature has troubled physicists. Take, for example, a superposition – is a particle actually inhabiting many places at once, or is the calculation of its position giving us a range of probabilities for where it actually is? If it is the latter, there may be some feature of reality that is hidden to quantum mechanics that limits our certainty. Such a feature would be a “hidden variable”, and so theories predicated on this idea are called hidden variable theories.

In the 1960s, physicist John Bell devised an experiment to rule out such theories. A Bell test probes quantumness by measuring how linked, or entangled, distant pairs of quantum particles are. If their quantum properties are maintained above a certain threshold – if their entanglement is what we call non-local, spanning any distance – then we could rule out hidden variable theories. Bell tests have since been tried for many quantum systems, unanimously ruling in favour of the inherent non-locality of the quantum world.

In 2012, physicists Matthew Pusey, Jonathan Barrett and Terry Rudolph came up with an even more probing test (named PBR after them), which would allow experimenters to differentiate between various interpretations of a quantum system. These include the ontic view, which says our measurements of a quantum system and its wave function – the mathematical description of its quantum states – represent reality. Another interpretation, called the epistemic view, says this wave function is a mirage and there exists a deeper, richer reality underneath.

Assuming you believe that quantum systems don’t have some other secret feature that can affect systems beyond the wave function, then the mathematics of the PBR show that you should always get an ontic view of things – that however weird they may look, quantum behaviours are real. The PBR test works by comparing different quantum elements, such as a qubit inside a quantum computer, and measuring how often they read out the same value for some property, such as their spin. If the epistemic view were correct, the amount of times that your qubits read the same value would be higher than quantum mechanics predicts, indicating something else is going on underneath.

Songqinghao Yang at the University of Cambridge and his colleagues have devised a way to carry out the PBR test on a working IBM Heron quantum computer, and they saw that for small numbers of qubits, we can indeed say that quantum systems are ontic. That is, quantum mechanics appears to work as we thought, just as Bell tests have repeatedly found.

Yang and his team carried out this check by measuring the overall output produced by pairs or groups of five qubits, such as strings of 1s and 0s, and calculated how often this result lined up with their prediction of how a quantum system should behave, accounting for the natural errors in the system.

“Currently, all quantum hardware is noisy, and there are some errors on all operations, so if we add in this noise on top of the PBR threshold, then what would happen to our interpretation [of our system]?” says Yang. “It turns out that if you do the experiment on a small scale, then we can still satisfy the original PBR test and we can rule out the epistemic interpretation.” Hidden variables, be gone.

While they could show this for small numbers of qubits, they struggled to do the same for larger numbers of qubits on the 156-qubit IBM machine. The noise, or errors, in the system became too great for the researchers to distinguish between the two scenarios in a PBR test.

This means the test can’t tell us if the world is quantum all the way up. It could be that at some scales, the ontic view wins out, while at larger scales we aren’t able to see precisely what quantum effects are doing.

Being able to verify a quantum computer’s “quantumness” using this test could be a way to confirm that these devices are doing what we think they are, as well as make them more likely to be able to display a quantum advantage – the ability to do a task that would take a classical computer an unreasonable amount of time. “If you want to have quantum advantage, you need to have quantumness inside your quantum computers, or else you can find an equivalent classic algorithm,” says team member Haomu Yuan at the University of Cambridge.

“The idea of using PBR as a benchmark of device performance is intriguing,” says Matthew Pusey at the University of York, UK, one of PBR’s original authors. But Pusey is less sure that it is telling us something about reality. “The main reason to do the experiment, rather than relying on theory, is if you think quantum theory could be wrong. But if quantum theory is wrong, what question are you even asking? The whole setup of ontic vs epistemic states presupposes quantum theory.”

To truly find a way to do a PBR test that would tell us about reality, you would need to find a way to do it without presupposing quantum theory is correct. “There are a minority of people who believe that quantum physics will fundamentally break down at some mesoscopic scale,” says Terry Rudolph at Imperial College London, another of the originators of the PBR test. “While this experiment is not likely relevant to ruling out any specific such proposal out there – to be clear, I don’t know one way or the other! – testing the fundamental features of quantum theory on ever larger systems always helps us narrow the search space of alternative theories.”

Reference: arXiv, DOI: arxiv.org/abs/2510.11213

HEALTH | OCT 31, 2025, 8:00 AM EDT | VIEW ON NEW SCIENTIST

The gut microbiome may play a role in shaping our personality

Rats given a faecal transplant from exuberant toddlers showed more exploratory behaviour, supporting the idea that gut bacteria might affect children’s emotional development

By Chris Simms

Faecal bacteria viewed with an electron microscope

Science Photo Library / Alamy Stock Photo

Rats given gut microbiome transplants from exuberant human toddlers seem to be more willing to explore their environment. This finding hints that the bacteria inhabiting our guts when we are children play a role in shaping our personalities.

“It suggests our microbes are active participants in emotional development, not just passive passengers,” says Harriët Schellekens at University College Cork in Ireland, who wasn’t involved in the study.

A growing body of research has linked the communities of microbes that reside in our guts to our health, emotions and moods. For example, people who lack certain types of gut bacteria seem to face a higher risk of depression or anxiety.

It isn’t entirely clear if the bacteria cause these changes or if the microbial community alters as a result of behaviour, but there are some signs that altering the make-up of the microbiome can influence one’s mood. For example, faecal transplants from people with depression to rats seem to induce depressive behaviour in the rodents, and people with depression treated with faecal transplants have had their symptoms improved in preliminary trials.

To shed more light on how the gut microbiome may be linked to temperament, Anna Aatsinki at the University of Turku in Finland and her colleagues transplanted faeces from toddlers to young rats.

First, the team evaluated the personalities of 27 2.5-year-old toddlers using a standard temperament assessment and an exercise in which children were invited to play with a bubble gun.

“We couldn’t really study things like anxiety disorder in 2-year-olds, but we thought there might be behaviour differences we could look at; if they are, for instance, behaviourally inhibited versus very outgoing and extroverted,” says Aatsinki.

Based on these assessments, the researchers judged 10 of the toddlers as exuberant, and eight as inhibited and introverted. From these groups, they selected four exuberant and four inhibited toddlers – half boys, half girls – and collected samples of their faeces.

Faecal samples with added glycerol or control samples of glycerol were transferred to 53 rats aged 22 or 23 days old, which had already had their bowels cleansed.

Aatsinki and her colleagues then put the rats through a series of behavioural tests in different situations. They found that rats with microbiomes from toddlers with high exuberance traits showed more exploratory behaviour than rats with a control transplant or rats receiving faeces from inhibited toddlers.

To explore how gut microbes might exert their influence on the brain, the researchers also analysed brain tissue from the rats, looking for changes in gene activity. This showed that rats given transplants from inhibited toddlers had less activity in neurons that produce dopamine, a brain chemical linked to reward for risk-taking behaviour.

“This study beautifully shows how the gut microbiome in early life may help shape behavioural tendencies,” says Schellekens. “By transferring microbiota from children to rodents, the researchers create a rare translational link between microbes, human temperament and brain function.”

This points to a gut–brain route that influences curiosity, reward and motivation via the dopamine system, says Schellekens.

The influence shouldn’t be overstated though, says Aatsinki. “Overall, adults’ temperament traits are relatively strongly correlated with genetics, but environmental factors, potentially including the microbiome, could influence the variance of some behaviours.”

Whether the microbes are behind behaviour differences in the children is still an open question, adds Aatsinki. It could also be that children who develop exuberant phenotypes interact with their environment and new foods differently, and so develop a different microbiome, she says.

Reference:

bioRxiv DOI: 10.1101/2025.10.10.681629

HUMANS | OCT 31, 2025, 11:13 AM EDT | VIEW ON NEW SCIENTIST

Denisovans may have interbred with mysterious group of ancient humans

We now have only the second high-quality genome from an ancient Denisovan human, which reveals there were more populations of this species than we thought

By Michael Marshall

Illustration of a teenage girl who is the offspring of a Neanderthal mother and Denisovan father

JOHN BAVARO FINE ART/SCIENCE PHOTO LIBRARY

For only the second time, researchers have obtained the full genome of a Denisovan, a group of ancient humans who lived in Asia. The DNA was extracted from a single 200,000-year-old tooth found in a Siberian cave.

The genome reveals that there were at least three populations of Denisovans, with different histories. It also shows that early Denisovans interbred with an unidentified group of ancient humans – and with a hitherto-unknown population of Neanderthals.

“This is a bombshell paper,” says David Reich at Harvard University.

“This study really expanded my understanding of the universe of the Denisovans,” says Samantha Brown at the National Research Center on Human Evolution in Spain.

Denisovans were the first ancient humans to be described using just DNA. A sliver of finger bone from Denisova cave in Siberia held DNA unlike that of either modern humans or the Neanderthals from western Eurasia. The genome revealed that Denisovans interbred with modern humans: people in South-East Asia, including the Philippines and Papua New Guinea, carry Denisovan DNA.

Since the initial reports in 2010, researchers have identified a handful of other Denisovans, all from East Asia. In June, a skull from Harbin, China, was identified as a Denisovan using molecular evidence, revealing for the first time what a Denisovan face looked like. However, while several specimens have yielded fragments of DNA, the original specimen has been the only one to yield a high-quality genome.

Researchers led by Stéphane Peyrégne at the Max Planck Institute for Evolutionary Anthropology in Germany have now added a second. (Peyrégne declined to be interviewed because the study hasn’t yet been peer-reviewed.)

The team found a single molar tooth, belonging to a male Denisovan, in Denisova cave in 2020 and sequenced an entire genome from the preserved DNA.

Based on the number of mutations in the genome and comparisons to other ancient humans, the team estimated that the individual lived about 205,000 years ago. In line with this, the sediments in which the tooth was found were dated to 170,000-200,000 years ago. In contrast, the other high-quality genome is from a Denisovan who lived 55,000-75,000 years ago, meaning that the new genome reveals a much earlier stage of Denisovan history.

Based on comparisons with other remains from Denisova cave, the team says there seem to have been at least three discrete Denisovan populations. The oldest group included the male whose tooth was analysed. A second group replaced this older population at Denisova cave, thousands of years later.

“Understanding how early Denisovans were replaced by later Denisovans highlights a significant human event,” says Qiaomei Fu at the Institute of Vertebrate Paleontology and Paleoanthropology in China.

The third group, not represented at the cave, interbred with modern humans, based on DNA testing. In other words, all the Denisovan DNA in modern humans comes from a population of Denisovans that we know little or nothing about.

The new genome reveals that Denisovans repeatedly interbred with Neanderthals, who sometimes lived in or near Denisova cave. Crucially, the genome includes traces of a Neanderthal population that lived 7000-13,000 years before the male Denisovan. These traces don’t match any known Neanderthal genome, suggesting the Denisovans interbred with a Neanderthal group that has not yet been sequenced.

The Denisovans also seem to have interbred with an unidentified group of ancient humans, one that had evolved independently of Denisovans and modern humans for hundreds of thousands of years. One possibility is Homo erectus, which, based on current knowledge, was the first hominin to migrate outside of Africa, living as far afield as Java, Indonesia. However, no DNA has yet been recovered from H. erectus, so we can’t be sure.

“It’s endlessly fascinating that we keep discovering these new populations,” says Brown.

Journal reference

bioRxiv DOI: 10.1101/2025.10.20.683404

CHEMISTRY | OCT 31, 2025, 11:00 AM EDT | VIEW ON NEW SCIENTIST

Bulletproof fabric laced with carbon nanotubes is stronger than Kevlar

A sheet of fabric that is three times stronger than Kevlar could stop a bullet despite being just 1.8 millimetres thick, thanks to the addition of carbon nanotubes that keep its molecules aligned

By James Woodford

The bulletproof fabric is both lightweight and strong

Jin Zhang Group, Peking University

A new material is so strong that just a 1.8-millimetre-thick sheet of it could stop a bullet, making it far stronger than Kevlar and possibly the strongest fabric ever made.

Bulletproof vests work by spreading the energy of a projectile through a network of connected fibres. In the case of Kevlar, these fibres are made from aramids, a group of polymer chain chemicals known for having extreme strength. However, under extreme stress, these polymer chains can slip, limiting the protection they offer.

For the past six years, Jin Zhang at Peking University, China, and his colleagues have been trying to develop even stronger materials than Kevlar or Dyneema, which is a different kind of polyethylene fibre and often cited as the world’s strongest fabric.

“Ultra-high dynamic strength and toughness are crucial for fibrous materials in impact-protective applications,” Zhang says. “These include bullet-proofing armours, vehicles, and aircraft.”

Now his team has worked out a method of aligning carbon nanotubes with aramid polymer chains to prevent the molecules from slipping. “Our new fibre significantly surpasses all reported macroscopic high-performance polymer fibres,” says Zhang. “Our fabric outperforms Kevlar entirely.”

The new material is a “fabricated carbon nanotube/heterocyclic aramid composite”, says Zhang, but he hopes to come up with a snappier name along the lines of Kevlar “at a later date”.

Because the material is stronger than Kevlar, the same bulletproof effect can be achieved with much less material. A single layer of fabric is approximately 0.6 millimetres thick and can reduce the velocity of a bullet travelling at 300 metres per second to 220 m/s, says Zhang. “Based on energy-absorption calculations, roughly three layers of fabric are sufficient to stop the bullet,” making a total thickness of 1.8 mm. By comparison, Kevlar must be at least 4 mm thick to stop that same bullet.

Julie Cairney at the University of Sydney, Australia, says the combination of aramid fibres and oriented carbon nanotubes is innovative.

“This approach could potentially be used to produce other new composites,” Cairney says. She also says the manufacturing strategy is compatible with existing industrial processes, making it promising for scalable production and real-world adoption.

“For personal and military protection, these materials could be used for lighter, more effective bulletproof vests and armour, enhancing safety without sacrificing mobility,” she says.

Journal reference:

Matter DOI: 10.1016/j.matt.2025.102496

ENVIRONMENT | OCT 31, 2025, 8:32 AM EDT | VIEW ON NEW SCIENTIST

Your flight emissions are way higher than carbon calculators suggest

Existing tools that work out the carbon footprint of flights greatly underestimate their warming impact, say the makers of a new calculator

By Michael Le Page

Contrails from jet engines can add to the warming effect of flying

Image Professionals GmbH/Alamy

If you’ve been using carbon footprint calculators to work out the impact of the flights you take, brace yourself. The true impact of your flying could be several times higher than commonly used CO₂ calculators suggest.

“The numbers are shocking,” says Jhuma Sadhukhan at the University of Surrey in the UK. She and her colleagues compared the figures from four established calculators with one they created.

For instance, suppose you fly first class from Singapore to Zurich on a B777 plane. At the time the study was done, the International Civil Aviation Organization (ICAO) and International Air Transport Association (IATA) flight calculators suggested this would produce the equivalent of around 3000 kilograms of carbon dioxide. The Google Travel Impact Model (TIM) said around 5000 kg while MyClimate put it at around 8000 kg. But according to a flight emissions calculator created by Sadhukhan and her colleagues, the actual number is more than 14,000 kg.

“The impact is considerably higher,” says team member Eduard Goean of the University of Surrey and Therme Group, a resort company based in Austria.

The new calculator, called the Air Travel Passenger Dynamic Emissions Calculator (ATP-DEC), differs from existing ones in two ways. Firstly, rather than assuming a flight takes the ideal route, it uses past flight data to estimate the most likely route, flight time and time spent taxiing before take-off and after landing, as well as how full an aeroplane is likely to be.

Unlike other calculators, this one is dynamic in the sense that the past flight data is continually updated, says Goean. For instance, many flights are taking longer routes because of Russia’s war on Ukraine – other flight calculators still don’t take account of this, the researchers say.

The second key difference is that ATP-DEC takes account of all the known ways in which flying can affect the climate, including the formation of contrails, nitrogen oxides and water vapour. Contrails, for instance, can have a greater warming effect than the CO₂ emissions from an aircraft.

Other flight calculators either don’t include these factors at all, or use an averaged value. “They don’t vary with the aircraft, or the fuel conditions, or the external conditions,” says Sadhukhan. “Ours is more comprehensive.”

Goean says the team will be making their calculator available to others, as well as producing an app that will come out early next year. “If an airline company wants to integrate ATP-DEC, we can start tomorrow,” he says. But it could take weeks or months to set up the necessary data feeds.

Flight emissions calculators sometimes offer passengers the chance to voluntarily pay a small fee to “offset” their emissions. However, some studies have concluded that many offsetting schemes do not deliver on their promises.

A spokesperson for ICAO said the methodology behind the ICAO Carbon Emissions Calculator can be found on its website. “The calculator does not quantify the climate change impact of aircraft emissions using the Radiative Forcing Index [a measure that accounts for non-CO2 gases] or other such multipliers, as scientific consensus has not yet been reached,” they said in a statement.

“The TIM is an accurate, transparent, and free resource to help consumers choose less-emitting flights,” says Dan Rutherford at the International Council on Clean Transportation, a nonprofit that helps advise Google on how to refine its CO₂ calculator. “We continue to improve the model, including the incorporation of short-lived climate pollutants like contrails, in order to maximise its usefulness to the flying public.”

“We appreciate this study as a valuable addition to the ongoing discussion,” says Kai Landwehr at MyClimate. Uncertainties about the warming effects of, say, contrails mean no method can claim to be absolutely right, but using better and more up-to-date data will enhance accuracy, Landwehr says. “We are planning an update to our calculator in the coming couple of months and intend to incorporate the best practices and current knowledge highlighted in this study.”

IATA was also contacted for comment.

Journal reference:

Communications Earth & Environment DOI: 10.1038/s43247-025-02847-4

HEALTH | OCT 30, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

Magnetic gel could remove kidney stones more effectively

Standard techniques for removing kidney stones often require repeated surgery, but a magnetic gel seems to make the process more efficient

By Carissa Wong

Kidney stones are a common and painful complaint

wildpixel/Getty Images

A magnetic device may be able to remove kidney stones more efficiently than standard approaches, avoiding the need for repeated surgical procedures.

Kidney stones occur when minerals in urine crystallise. They can be painful when they become lodged inside the kidneys or enter the ureters, tubes that connect the kidneys to the bladder.

They are often treated by breaking them into smaller pieces. This may involve pushing a thin tube with a stone-shattering laser at the end through the bladder into the ureter and kidney, or pulsing ultrasound waves from outside the body.

Surgeons can then remove the stone fragments, usually one by one, using a wire basket that is fed in and out of the urethra. But this repeated retrieval can cause tissue damage. In about 40 per cent of cases, fragments are left behind, partly because especially small ones slip through the basket. These carry the risk of forming more stones.

In search of an alternative approach, Joseph Liao at Stanford University in California and his colleagues previously developed a magnetic gel, which coats kidney stone fragments, and a magnetic wire, which they used to capture the fragments in a lab dish.

Now, they have tested the approach in four pigs. They inserted dozens of human kidney stone fragments into the animals’ kidneys before injecting the organs with the magnetic gel. Using the magnetic wire inserted through the urethra, they were able to retrieve multiple stone fragments at once, rather than just one at time, as is commonly the case with the wire basket method.  “It’s sort of like using a stick to fish out a snot full of stone fragments, so you can remove a large amount of them in one” go, says Liao.

This suggests the technique would cause less tissue damage than the standard approach, as surgeons would need to go in and out of the kidneys fewer times. It could even completely clear fragments from the kidneys because, unlike wire baskets, the magnetic device can catch pieces of any size, says Liao. This would reduce the risk of new stones forming and the need for further surgery.

“It’s a very promising approach,” says Veronika Magdanz at the University of Waterloo in Canada, who wasn’t involved in the study. “Anything that increases the collection success of the stones and picks up more pieces at a time is helpful.”

None of the pigs showed side effects due to the gel. “It’s very good news; it’s not toxic or damaging in any way,” says Magdanz. After optimising the approach in further pig studies, the team hopes to trial it in humans in about a year, says Liao.

Journal reference:

Device DOI: 10.1016/j.device.2025.100971

HUMANS | OCT 31, 2025, 2:00 AM EDT | VIEW ON NEW SCIENTIST

Boy's body was mummified and turned green by a copper coffin

The green mummified remains of a teenager buried in Italy 200 to 400 years ago have given us new insights into the preservative properties of copper

By Christa Lesté-Lasserre

The mummified remains of a boy buried in a copper box between 1617 and 1814

Annamaria Alabiso

An adolescent boy buried around three centuries ago in a copper box in northern Italy has become the only near-complete green mummy ever known.

Other ancient body parts have been partially mummified or turned green after burial with copper or bronze objects, like the green, mummified hand of a newborn baby clutching a copper coin, buried in a ceramic pot in medieval Hungary.

The Italian mummy, however, is complete except for the feet. Apart from its left leg, it is almost entirely green from skin to bone.

The mummy was discovered in the basement of an ancient villa in Bologna in 1987 and sent for forensic analysis at the University of Bologna. Medical examiners determined it was the body of a boy aged 12 to 14. Since then, it has been carefully stored at the university.

Annamaria Alabiso, a conservation scientist at the University of Rome Tor Vergata, was part of an investigation of the mummy by a wide array of specialists, including geneticists, anthropologists, radiologists, mathematicians, physicists and computer scientists. “It was a very remarkable multidisciplinary collaboration,” she says.

The researchers ran multiple in-depth chemical and physical analyses of the mummy. Radiocarbon dating placed the boy’s death to between 1617 and 1814, says Alabiso, and the mummy shows no clear signs of trauma or disease.

Copper helped preserve the hard and soft tissues – as expected, given its known antimicrobial properties, says Alabiso. But it also reacted with acids that leaked out of the body and corroded the box. This created copper corrosion products that interacted with chemical compounds in the bone. Little by little, copper ions replaced calcium in the boy’s skeleton, solidifying the bone structure in the long term while tinting the affected areas various shades of green.

As for the skin, it was covered by a crusty film of copper corrosion products called patina – the pale-green coating that develops on copper and bronze statues. The patina developed when copper reacted with water and carbon dioxide as the body broke down, says Alabiso.

“This completely changes our point of view on the role of heavy metals, as their effects on preservation are more complex than we might expect,” she says.

The bottom of the box eventually cracked open – possibly due to the acid – letting the liquid spill out so that the body stayed in a cool, dry chamber with little oxygen, which slowed decomposition. The boy’s feet might have detached and got lost at this time, says Alabiso.

“It was just a very emotional experience for me to work with these unique human remains,” she says.

Giulia Gallo at the Collège de France in Paris recently saw images of the mummy for the first time – and was delighted. “Oh wow, it’s incredible!” she says. “It’s so beautiful! This whole case study is quite fascinating.”

Gallo says the researchers have done an excellent job of exploring all the physical and chemical processes leading to the body’s mummification and colour changes. “The evidence strongly substantiates their argument concerning both the preservation and coloration of the tissue and bone.”

Journal reference:

Journal of Cultural Heritage DOI: 10.1016/j.culher.2025.09.013

Historic Herculaneum – Uncovering Vesuvius, Pompeii and ancient Naples

Embark on a captivating journey where history and archaeology come to life through Mount Vesuvius and the ruins of Pompeii and Herculaneum.

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ANALYSIS: PHYSICS | OCT 30, 2025, 12:10 PM EDT | VIEW ON NEW SCIENTIST

The US is unlikely to test nuclear weapons, despite what Trump says

President Donald Trump appears to have ordered a return to nuclear testing after decades of uneasy but effective treaties banning the practice – but will it actually happen?

By Matthew Sparkes

Donald Trump made his announcement before meeting with Chinese president Xi Jinping in South Korea

Andrew Harnik/Getty Images

US President Donald Trump has said that the country will resume nuclear weapons testing after a decades-long ban. But researchers speaking to New Scientist say there is no scientific need for such tests and they would be purely symbolic, unsettling for global peace and likely to spark protests among US citizens. In short, they are unlikely to happen – but that doesn’t mean the announcement is entirely benign.

Trump announced the new policy in a post on Truth Social, saying that because of “other countries [sic] testing programs, I have instructed the Department of War to start testing our nuclear weapons on an equal basis. That process will begin immediately.”

The announcement had little in the way of detail, but also confused experts because no other nation is actually testing nuclear bombs. Russia recently demonstrated a nuclear-powered underwater drone and a nuclear-powered missile, but neither were actually nuclear detonations.

Certainly, in the wake of Russia’s invasion of Ukraine, there were signs that several countries were preparing their historic nuclear weapons testing sites – whether with true intent to test once more or merely for political posturing. Modernisation work has taken place at China’s test site in the far-western region of Xinjiang, as well as at Russia’s in an Arctic Ocean archipelago and the US test site in the Nevada desert.

But new tests would run counter to decades of uneasy but effective bans. The Limited Test Ban Treaty was signed by the UK, the US and the Soviet Union in 1963, forbidding testing of these weapons in the atmosphere, underwater or in outer space, but permitting underground trials. Then, in 1996, the Comprehensive Nuclear-Test-Ban Treaty (CTBT) theoretically put a stop to underground testing too, and although it was never technically ratified, it has been effective.

More than 2000 tests took place between the first US detonation, Trinity, in 1945 and the drafting of the CTBT. Since then, India and Pakistan each carried out a handful of tests in 1998, while North Korea is the only nation to have tested a nuclear weapon in the 21st century, with its last test taking place in 2017. The US hasn’t tested a nuclear weapon since 1992.

Given that context, most experts are sceptical that President Trump – who has been vocal about his desire to be awarded a Nobel Peace Prize – would lead the US to become the first global superpower to resume nuclear testing.

John Preston at the University of Essex, UK, says the president’s statement might be little more than “Trumpian rhetoric” with no real intent to detonate nuclear weapons behind it, but warns that even this could be dangerous. Historically, Soviet and Russian strategy has been to escalate to de-escalate, he says – acting aggressively to force adversaries to take a step back.

Preston says that during the cold war, nuclear powers spent a great deal of time and energy bringing in experts from varied fields to understand exactly how nuclear arms tests and proliferation could escalate conflict. But in the years since, that has been less of a focus, and the topic has become highly secretive in general.

“In policy circles, in nuclear-strategy circles, I fear there’s probably less of an understanding of the ladder of escalation,” says Preston. “All the science is really known about the effects of nuclear weapons. There’s nothing more to know.
So it would be purely symbolic and just take us up a ladder of escalation that we don’t really understand anymore.”

There would certainly be little scientific pay-off from such a move. Nuclear tests today are done extremely accurately in physics simulations on vast supercomputers. The world’s two most powerful computers (of those that are publicly disclosed, at least) are both run by the US government and are used to ensure the effectiveness of the US nuclear deterrent without having to carry out physical testing.

Christoph Laucht at Swansea University, UK, says that a resumption of testing would be a backwards step at a dangerous moment in history. The New START treaty is set to expire on 4 February 2026 and the Intermediate-Range Nuclear Forces Treaty is already over, meaning Russia and the US are just months from having no formal nuclear treaties in place, with little prospect of reaching new agreements in the current tense geopolitical climate.

“I think there is a legitimate concern that this might might be the start of a new kind of nuclear arms race,” says Laucht. “We still have a vast number of nuclear warheads, but we’re actually moving in terms of treaties to something which is comparable to the early cold war, when there was no arms limitation treaty.”

The risk is that if any one country resumes testing, others will feel compelled to follow suit, says Laucht. And testing would probably lead to protests from environmental groups, peace activists and citizens near the Nevada test site, making an already polarised US even more tense.

Sara Pozzi at the University of Michigan is blunt that resuming nuclear explosive testing makes no sense for the US. “Doing so would undermine global stability, provoke other nations to restart their own nuclear explosive testing programmes and threaten decades of progress toward nuclear arms control,” she says. “Instead, the US should continue to lead by example and help reinforce global efforts to prevent nuclear proliferation.”

There is, of course, another argument: that Trump, in characteristic fashion, has leapt to posting mercurial, unspecific and vague statements on social media that don’t tell the full story.

Nick Ritchie at the University of York, UK, says Trump may well just be talking about testing nuclear delivery technology, like the missiles that launch them, rather than warheads themselves – especially as a resumption of testing warheads would probably mean years of planning, engineering and political work that would outsee his presidency. But if that is the case, then confusion remains, as these technologies are, and always have been, tested on a regular basis, along with those of NATO allies.

“It’s a very Trumpian way of communicating on all sorts of political issues, including on very potentially destabilising and dangerous issues like American nuclear weapons policy,” says Ritchie. “There’s a fringe possibility that that I might be wrong and preparations may be very well advanced for a return to nuclear testing, but I’ve certainly seen no indications of that whatsoever.”

LIFE | OCT 30, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

Dinosaur skeleton settles long debate over 'tiny T. rex' fossils

Palaeontologists have argued for decades over whether certain fossils are young Tyrannosaurus rex or another species entirely – now they have strong evidence that the diminutive Nanotyrannus really existed

By James Woodford

Artist’s impression of a pack of Nanotyrannus attacking a juvenile T. rex

Anthony Hutchings

A dinosaur fossil thought to be a juvenile Tyrannosaurus rex is in fact a fully grown carnivore of a different species, according to researchers who believe they have finally settled a long-running and fierce debate in palaeontology.

The dispute stems from a skull found in Montana’s Hell Creek Formation in the 1940s, originally classified as a Gorgosaurus, then suggested to be a juvenile T. rex. In 1988, other researchers argued that the fossil was in fact an adult of a smaller, related species, which they named Nanotyrannus lancensis.

A number of additional fossils have since been identified as Nanotyrannus, but many palaeontologists believe they are really juvenile T. rex specimens.

Now, for the first time, researchers have analysed a complete skeleton that appears to show beyond doubt that Nanotyrannus is a separate species.

The skeleton is one of a pair from a fossil specimen nicknamed the “Duelling Dinosaurs”, which was discovered by commercial fossil hunters in 2006. The fossil features a Triceratops buried alongside what was originally thought to be a juvenile T. rex around 67 million years ago.

It wasn’t until 2020, when the fossil was purchased by the North Carolina Museum of Natural Sciences, that palaeontologists could comprehensively study the remains.

“When we acquired the specimen, we knew it was exceptional,” says Lindsay Zanno at the North Carolina Museum of Natural Sciences. “We had no idea it would turn decades of research on the world’s most famous dinosaur on its head.”

Zanno, who did the analysis with her colleague James Napoli at Stony Brook University in New York, says she had originally been an adherent of the juvenile T. rex theory, but the evidence has forced her to reconsider.

“Nanotyrannus has different nerve and sinus patterns in the skull, more teeth, large hands and a shorter tail,” she says. “We know that these traits do not change as animals grow from baby to adult.”

Lindsay Zanno with the proposed Nanotyrannuslancensis skeleton

NC State University

According to Zanno and Napoli, detailed analysis of limb bones of the dinosaur confirm it was a fully grown individual about 20 years old, weighing around 700 kilograms and measuring about 5.5 metres in length. “That’s about one-tenth the body mass and one-half the length of a fully grown Tyrannosaurus,” says Zanno.

Zanno and Napoli also reanalysed 200 tyrannosaur fossils and concluded that another near-complete skeleton from the Hell Creek Formation, known as Jane, which was thought to be a T. rex teenager, has also been incorrectly classified. They say Jane is actually a new species in the genus Nanotyrannus, which they call Nanotyrannus lethaeus.

“We only have one skeleton of N. lethaeus, but its anatomy suggests it was a larger species,” says Zanno. “The sinus patterns in the palate and the shape of the bone behind the eye are unique.”

The putative Nanotyrannus lancensis skull has more teeth than that of T. rex.

MATT ZEHER/NC Museum of Natural Sciences

Scott Persons at South Carolina State Museum says the new study resolves the debate about Nanotyrannus being a distinct genus and species.

“For my money, Nanotyrannus was one of the scariest dinosaur predators,” says Persons. “It’s the one I would least like to be chased by. It was extremely long-legged and armed with a wicked thumb claw.

“We can think of Nanotyrannus and Tyrannosaurus as analogues to modern cheetahs and lions. Yes, they have a generally similar body plan, but they were specialised for different ways of hunting.”

Thomas Carr at Carthage College in Wisconsin, who has long sat in the juvenile T.rex camp, says the new evidence is “pretty conclusive” that the Duelling Dinosaur specimen is a “near-adult of a species that is not T. rex”.

And Holly Ballard at Oklahoma State University, who led a 2020 study refuting the Nanotyrannus claims, says she is “fine” with the team’s conclusion that the fossil is of an individual approaching adult size.

But neither Ballard nor Carr is convinced that the other fossil, Jane, represents a new Nanotyrannus species. “Jane is still growing and is already bigger than N. lancensis, so to argue it’s a new taxon instead of a juvenile T. rex,” says Ballard. “We’re back to the same old debates.”

“In addition to that, if every small tyrannosaur from the Hell Creek Formation is Nanotyrannus, then where are the juvenile T. rex?” says Carr. “That part of the picture doesn’t add up. In terms of fossils, we simply haven’t collected enough Hell Creek Formation tyrannosaurs to truly understand what was going on with the early growth stages of T. rex.”

Journal reference:

Nature DOI: 10.1038/s41586-025-09801-6

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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TECHNOLOGY | OCT 30, 2025, 6:00 AM EDT | VIEW ON NEW SCIENTIST

Germanium superconductor could help build reliable quantum computers

A new type of germanium superconductor could allow classical and quantum chips to be built into one device, creating better and more reliable quantum computers.

By Matthew Sparkes

Germanium is already used in standard computer chips

matejmo/Getty Images

A superconductor made from germanium, a material commonly used to build computer chips, could one day create better and more reliable quantum computers.

Superconductors are materials that conduct electricity with no resistance, which is useful if you are making any sort of electrical device. They also maintain quantum coherence, which is beneficial if you are trying to build a useful quantum computer.

But while previous superconductors have tended to be unusual materials that wouldn’t be easy to incorporate into computer chips, Peter Jacobson at the University of Queensland, Australia, and his colleagues have created one from germanium, which is already widely used by the computing industry.

The researchers created their superconductor by infusing a film of germanium with gallium, a process known as doping. Previous research along these lines found that the combination eventually became unstable. To avoid this, the team used X-rays to force more gallium into the material and thus create uniform and stable patterns.

Like other known superconductors, however, this new material doesn’t work at room temperature. It needs to be cooled to 3.5 kelvin (-270°C/-453°F).

David Cardwell at the University of Cambridge says that the superconductor’s need for extremely cold temperatures rules it out for use in consumer devices, but that it could be a perfect fit for quantum computing, which also tends to need super-cooling.

“It could be transformational for quantum,” says Cardwell. “This gives a whole new level of functionality, because you’ve got a very cold environment anyway. That would be, I think, the obvious starting point.”

Jacobson says that previous work that layered superconductors on top of semiconductors, a key component of computing devices, caused defects in the crystal structure, which cause problems when it comes to applications. “Disorder is really a parasitic effect in quantum technology,” he says. “It causes absorption of your signals.”

But the new material allows layers of gallium-doped germanium and layers of silicon to sit on top of each other with a uniform crystal structure throughout, potentially allowing for the manufacture of chips that merge the best properties of semiconductors and superconductors.

Journal reference

Nature Nanotechnology DOI: 10.1038/s41565-025-02042-8

HEALTH | OCT 29, 2025, 7:30 PM EDT | VIEW ON NEW SCIENTIST

Stem cell therapy lowers risk of heart failure after a heart attack

People who receive stem cell therapy within a week of their first heart attack have nearly a 60 per cent lower risk of developing heart failure years later

By Grace Wade

Mesenchymal stem cells labeled with fluorescence molecules

Vshivkova/Shutterstock

People who received an infusion of stem cells shortly after a heart attack were less likely to develop heart failure than those treated with standard care, according to the largest such trial to date. The finding provides some of the strongest evidence yet that stem cells can help the heart repair itself.

After a heart attack, cardiac muscle is permanently damaged and weakened, which often leads to heart failure – when the organ can’t pump enough blood to meet the body’s demands. Currently, there is no treatment short of a transplant or heart pump that can restore cardiac function.

As a potential solution, researchers have turned to stem cells, which have the unique ability to transform into other cell types. But previous studies investigating their use after a heart attack have shown mixed results. For instance, a 2020 trial involving 375 people found bone marrow-derived cells, including stem cells that develop into blood cells, failed to lower the risk of death to a greater degree than standard care, such as cardiac rehabilitation programmes and medications to lower blood pressure, reduce blood clots or decrease cholesterol.

Armin Attar at Shiraz University in Iran and his colleagues took a different approach: they used mesenchymal stem cells, which can differentiate into structural cells such as cartilage and fat. These stem cells also release molecules that reduce inflammation and spur surrounding tissues to regenerate.

The team collected mesenchymal stem cells from umbilical cord blood and infused them into the hearts of 136 people within three to seven days of their first heart attack. While these stem cells could be taken from participants’ own fat and bone tissue, culturing enough of them for an infusion can take a month, says Attar. Using those from umbilical cord blood allowed the team to administer the treatment much sooner, potentially enhancing the effects, he says. A separate group of 260 people received standard care after their first heart attack.

Three years later, those who underwent stem cell therapy were, on average, 57 per cent less likely to develop heart failure and 78 per cent less likely to be hospitalised for the condition than those receiving standard care. They also saw significant improvements in the heart’s ability to pump blood, suggesting the treatment helps heart tissue regenerate after damage.

“This is a great step forward,” says Attar. While the therapy didn’t reduce the risk of death during the study period, the fact it lowered hospital admissions is still notable, says Hina Chaudhry at the Icahn School of Medicine at Mount Sinai in New York. “Heart failure is the leading cause of hospitalisation in the US,” she says.

However, 80 per cent of the participants were men, making it less clear how the therapy affects women, who are more susceptible to heart failure after a heart attack, Chaudhry says. However, Attar and his team didn’t find outcomes differed by gender in a separate analysis. The study was also limited to younger adults; all of the participants were between 18 and 65 years old. “It would be good to see a breakdown of age groups because younger patients just have more natural regenerative ability, and they recover better from heart damage,” says Chaudhry.

These results are the strongest indication yet that stem cells can help restore cardiac function after a heart attack. But the treatment doesn’t heal the heart entirely. “There is no drug, no therapy on this planet that replaces those lost [heart muscle cells]. And that is what is really going to be a game changer in the field,” says Chaudhry. Still, “all of this research is teaching us more about the regenerative process in the heart and how to get there”, she says.

Journal reference:

The BMJ DOI: 10.1136/bmj-2024-083382

SPACE | OCT 29, 2025, 4:03 PM EDT | VIEW ON NEW SCIENTIST

A tiny nearby galaxy is home to a shockingly enormous black hole

One of the Milky Way’s smallest galactic neighbours seems to have a supermassive black hole at its centre, upending assumptions that it was dominated by dark matter

By Leah Crane

It is hard to believe, but Segue 1, a very faint dwarf galaxy, is at the centre of this image

CDS, Strasbourg, France/CDS/Aladin

A nearby galaxy once thought to be dominated by dark matter seems to have a surprise supermassive black hole at its centre. Segue 1 is barely a galaxy, with only about 1000 stars compared to the Milky Way’s hundreds of billions, and yet it appears to be home to a black hole about 10 times as massive as all its stars combined.

Segue 1 and other similar dwarf galaxies do not have enough stars to provide the gravity needed to hold them all together. To solve that problem, physicists have long assumed they were chock-full of the mysterious substance called dark matter, which we can’t see but that could generate the extra gravity.

So when Nathaniel Lujan at the University of Texas at San Antonio and his colleagues began testing computer models of Segue 1, they expected the best-fitting model would be one dominated by dark matter. “I was running hundreds of thousands of models, and I wasn’t finding anything that fit,” says Lujan. “And then finally I decided to mess with the black hole mass and all of a sudden it started to work.”

The model that fit best with our observations of Segue 1 included a black hole with a mass about 450,000 times the mass of the sun. This was particularly surprising not only because of the galaxy’s lack of stars, but also because of its age – the few stars that it does have indicate it formed only about 400 million years after the very beginning of star formation in the universe. That doesn’t leave much time to produce such a colossal black hole, especially with the much larger Milky Way siphoning off most of the gas that could feed it from Segue 1 shortly after its birth.

“This probably means that there are more supermassive black holes than we thought,” says Lujan. If so, they could account for some of the gravity that has until now been attributed to dark matter – but we don’t yet know if Segue 1 is representative of all dwarf galaxies, so the hunt for more supermassive black holes is on.

Journal reference

The Astrophysical Journal Letters DOI: 10.3847/2041-8213/ae0b4f

HUMANS | OCT 29, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

Prehistoric crayons provide clues to how Neanderthals created art

Ochre artefacts found in Crimea show signs of having been used for drawing, adding to evidence that Neanderthals used pigments in symbolic ways

By Alison George

Neanderthals may have used ochre crayons to draw on cave walls

Gorodenkoff/Getty Images

A remarkable yellow crayon unearthed in Crimea, still sharp after more than 40,000 years, indicates that painting lines on objects was part of Neanderthal culture. This discovery is the firmest evidence yet that some Neanderthal groups used coloured pigments in symbolic ways – behaviour once regarded as the sole domain of our species.

“It’s really exciting. It adds a new facet to what we know about symbolic use of colour,” says Emma Pomeroy at the University of Cambridge, who wasn’t involved with the research.

The use of ochre – an iron-rich mineral with red, yellow or orange hues – has ancient roots, dating back at least 400,000 years in Europe and Africa. Bits of ochre are found at many Neanderthal sites, where they seem to have been used for practical purposes such as tanning clothing and as fire accelerants, as well as sometimes smeared on shell beads.

Neanderthals may have also used ochre to decorate their bodies, clothing and other surfaces, but such traces have long since disappeared. To investigate further, Francesco d’Errico at the University of Bordeaux, France, and his colleagues carried out a detailed analysis of ochre pieces found at Neanderthal sites in Crimea, Ukraine. By studying how ochre pieces were modified by Neanderthals, as well as performing a microscopic analysis of how they became worn down, the researchers could build a picture of how the objects were used.

The most compelling of these ochre objects was a yellow one that was at least 42,000 years old and had been ground and scraped into a crayon-like shape about 5 to 6 centimetres long. Detailed analysis shows that the tip had been worn down through use, then resharpened, indicating that it was reused over time as an implement to make marks.

“It was a tool that had been curated and reshaped several times, which makes it very special,” says d’Errico. “It’s not just a crayon by shape. It’s a crayon because it was used as a crayon. It’s something that may have been used on skin or a rock to make a line – the reflection, perhaps, of an artistic activity.”

The tip of an ochre fragment that has been used as a crayon and then resharpened

d’Errico et al., Sci. Adv. 11, eadx4722

April Nowell at the University of Victoria in Canada, who wasn’t involved with the research, concurs. “You only maintain a point on a crayon if you want to make precise lines or designs,” she says.

The research team also identified another more ancient broken crayon, perhaps 70,000 years old, made from red ochre.

“It tells us so much just from those small bits of ochre,” says Pomeroy. “It’s that little bit of humanity that we can relate to. It really brings those individuals into touching distance.”

The Crimean crayon discoveries add to the small but growing body of evidence indicating the artistic talents of Neanderthals, such as 57,000-year-old finger carvings on a cave wall in France and mysterious circles crafted from stalagmites 175,000 years ago in another French cave.

They also lend weight to the idea that symbolic behaviour has very deep roots in our evolutionary past, rather than being a capacity that developed relatively recently only in Homo sapiens. “The underlying cognitive ability for symbolic behavior is undoubtedly shared by the last common ancestor of Homo sapiens, Denisovans and Neanderthals more than 700,000 years ago,” says Nowell.

Journal reference:

Science Advances DOI: 10.1126/sciadv.adx4722

Ancient caves, human origins: Northern Spain

Discover some of the world’s oldest known cave paintings in this idyllic part of Northern Spain. Travel back 40,000 years to explore how our ancestors lived, played and worked. From ancient Paleolithic art to awe-inspiring geological formations, each cave tells a unique story that transcends time.

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TECHNOLOGY | OCT 29, 2025, 8:00 AM EDT | VIEW ON NEW SCIENTIST

Analogue computers could train AI 1000 times faster and cut energy use

Computers built with analogue circuits promise huge speed and efficiency gains over ordinary computers, but normally at the cost of accuracy. Now, an analogue computer designed to carry out calculations that are key to AI training could fix that

By Matthew Sparkes

Analogue computers use less energy than digital ones

metamorworks/Getty Images

Analogue computers that rapidly solve a key type of equation used in training artificial intelligence models could offer a potential solution to the growing energy consumption in data centres caused by the AI boom.

Laptops, smartphones and other familiar devices are known as digital computers, because they store and process data as a series of binary digits, either 0 or 1, and can be programmed to solve a range of problems. In contrast, analogue computers are normally designed to solve just one specific problem. They store and process data using quantities that can vary continuously such as electrical resistance, rather than discrete 0s and 1s.

Analogue computers can excel at speed and energy efficiency, but have previously lacked the accuracy of their digital counterparts. Now, Zhong Sun at Peking University, China, and his colleagues have created a pair of analogue chips that work together to accurately solve matrix equations – a fundamental part of sending data over telecom networks, running large scientific simulations or training AI models.

The first chip outputs a low-precision solution to matrix calculations very rapidly, while a second runs an iterative refinement algorithm to analyse the error rates of the first chip and so improve accuracy. Sun says that the first chip produces results with an error rate of around 1 per cent, but that after three cycles of the second chip, this drops to 0.0000001 per cent – which he says matches the precision of standard digital calculations.

So far, the researchers have built chips capable of solving 16 by 16 matrices, or those with 256 variables, which could have applications for some small problems. But Sun admits that tackling the questions used in today’s large AI models would require far larger circuits, perhaps a million by a million.

But one advantage analogue chips have over digital is that larger matrices don’t take any longer to solve, while digital chips struggle exponentially as the matrix size increases. That means the throughput – the amount of data crunched per second – of a 32 by 32 matrix chip would beat that of a Nvidia H100 GPU, one of the high-end chips used to train AI today.

Theoretically, scaling further could see throughput reach 1000 times that of digital chips like GPUs, while using 100 times less energy, says Sun. But he is quick to point out that real-world tasks may stray outside the extremely narrow capabilities of their circuits, leading to smaller gains.

“It’s only a comparison of speed, and for real applications, the problem may be different,” says Sun. “Our chip can only do matrix computations. If matrix computation occupies most of the computing task, it represents a very significant acceleration for the problem, but if not, it will be a limited speed-up.”

Sun says that because of this, the most likely outcome is the creation of hybrid chips, where a GPU features some analogue circuits that handle very specific parts of problems – but even that is likely some years away.

James Millen at King’s College London says that matrix calculations are a key process in training AI models and that analogue computing offers a potential boost.

“The modern world is built on digital computers. These incredible machines are universal computers, which means they can be used to calculate absolutely anything, but not everything can necessarily be computed efficiently or fast,” says Millen. “Analogue computers are tailored to specific tasks, and in this way can be incredibly fast and efficient. This work uses an analogue computing chip to speed up a process called matrix inversion, which is a key process in training certain AI models. Doing this more efficiently could help reduce the huge energy demands of our ever-growing reliance on AI.”

Journal reference

Nature Electronics DOI: 10.1038/s41928-025-01477-0

HEALTH | OCT 29, 2025, 6:15 AM EDT | VIEW ON NEW SCIENTIST

Can't focus after a bad night's sleep? Your dirty brain is to blame

During sleep, your brain cleans itself by flushing through cerebrospinal fluid to prevent damage to brain cells. If you're lacking in sleep, this happens when you are awake – and seems to cause momentary lapses in attention

By Carissa Wong

Struggling to concentrate? Maybe your brain is having a wash

Jenny Evans/Getty Images

We all know it can be hard to concentrate when you are sleep-deprived, but why does this happen? It may be because your brain is trying to refresh itself, causing momentary lapses in attention.

During sleep, the brain carries out a rinse cycle, where cerebrospinal fluid (CSF) is repeatedly flushed into the organ and out again at the base of the brain. This process clears out metabolic waste that has built up during the day – and that would otherwise damage brain cells.

Laura Lewis at the Massachusetts Institute of Technology and her colleagues wondered whether lapses in attention, which commonly occur after sleep deprivation, may result from the brain trying to catch up on rinsing itself when it’s awake.

To explore this idea, the researchers asked 26 people aged between 19 and 40 to get a good night’s sleep that left them feeling well-rested, then kept them awake all night in a lab two weeks later.

In both cases, the team recorded the participants’ brain activity using MRI scans the next morning, while they completed two tasks. During these tests, participants had to push a button whenever they heard a specific tone or saw a cross on a screen turn into a square. This occurred dozens of times over 12 minutes.

As expected, the participants failed to press the button substantially more often when they were sleep-deprived compared with when they were well-rested, meaning a lack of sleep made it harder to focus.

Crucially, when the researchers analysed the brain scans, they found that participants lost focus about 2 seconds before CSF was flushed out of the base of their brain. What’s more, CSF was drawn back into the brain about 1 second after attention recovered.

“If you think about the brain-cleaning process like a washing machine, you kind of need to put the water in and then slosh it around and then drain it out, and so we’re talking about the sloshing part occurring during these lapses of attention,” says Lewis.

The findings suggest that when the brain can’t clean itself during sleep, it does so when you’re awake, but this impairs concentration, says Lewis. “If you don’t have these waves [of fluid flowing] at night because you’re kept awake all night, then your brain starts to kind of sneak them in during the daytime, but they come with this cost of attention.”

Exactly why this cleaning process leads to a loss of attention remains unclear, but pinpointing the brain circuits that are responsible could reveal ways to reduce the cognitive effects of sleep deprivation, says Lewis.

Journal reference:

Nature Neuroscience DOI: 10.1038/s41593-025-02098-8

PHYSICS | OCT 28, 2025, 4:46 PM EDT | VIEW ON NEW SCIENTIST

Quantum-inspired algorithm could help reveal hidden cosmic objects

Combining a quantum-inspired algorithm and quantum information processing technologies could enable researchers to measure masses of cosmic objects that bend light almost imperceptibly

By Karmela Padavic-Callaghan

A galaxy cluster produces gravitational lensing, bending light around it

NASA, ESA, Michael Gladders (University of Chicago); Acknowledgement: Judy Schmidt

Quantum physics may be the secret ingredient for understanding cosmic objects that our telescopes cannot show us in detail, or at all.

To understand space, we collect and analyse light that travels from objects like stars into our telescopes, but that light doesn’t always travel in straight lines. Often, as it passes by a very massive object, such as a planet or a black hole, the light’s trajectory bends and creates distorted images as if an extra lens was added somewhere along the way.

But what about objects that are not cosmic heavyweights and have relatively small masses? Traditional imaging methods struggle with such “microlensing” events, but Zhenning Liu at the University of Maryland and his colleagues have now shown a protocol for analysing light that accounts for its quantumness could do much better.

They focused on leveraging the quantum properties of light to discern the mass of objects that cause microlensing. Liu says researchers can tell when a microlensing event happens, because the light becomes brighter. This allows them to know there is an object between us and the light’s source, but if that object is not huge, they cannot infer its mass from the properties of the light that telescopes already measure. Such objects could include small, isolated black holes and even some rogue planets.

But light is made from photons, which are quantum particles, so information about their journey towards Earth also gets encoded into their quantum properties. Notably, whenever a photon has the option of taking multiple different paths around an object, each of which requires a different travel time, that difference changes the photon’s quantum properties. Because quantum particles can sometimes behave like waves, these photons can effectively take both paths around an object simultaneously, like a water wave encountering a rock. The team’s protocol excels at extracting the time difference between both paths, which can then be translated into the object’s mass.

Liu says a planet or black hole creating microlensing would not necessarily be invisible in all other observations. But those methods may require collecting a lot more light, which is equivalent to having to build ever larger telescopes. The quantum approach would work with relatively few photons.

For instance, his team’s mathematical analysis showed the protocol would work well for stars in the galactic bulge, a part of the Milky Way where dark objects have previously been discovered through studies of gravitational lensing. Because the new protocol does not require a full-fledged quantum computer and could be implemented with more standard devices that capture and analyse one photon at a time combined with conventional computers, it also stands a chance of being tested in practice within a few years.

Daniel Oi at the University of Strathclyde in the UK says the quantum approach offers an exponential improvement in the ability to extract time delay information from light, an advantage that he likens to a holy grail of quantum technology. Oi says quantum technologies are a natural match for weak astronomical signals like small numbers of photons, because quantum theory is the origin of many of the limits on just how precisely something can be measured in physics.

Reference: arXiv, DOI: 10.48550/arXiv.2510.07898

ANALYSIS: HEALTH | OCT 28, 2025, 3:12 PM EDT | VIEW ON NEW SCIENTIST

US public health system is flying blind after major cuts

The Trump administration has laid off government workers integral to major public health surveys, meaning the country will lack crucial information on births, deaths and illnesses nationwide

By Grace Wade

The Trump administration has cut crucial US health surveys

Ken Cedeno/UPI/Bloomberg via Getty Images

Critical public health surveys in the US are facing deep cuts after a series of layoffs hit government employees working on key nationwide data systems. These datasets, which measure everything from births and deaths to nutrition and substance use, have guided health policy for decades. Without them, it will be nearly impossible to identify, monitor or respond to health threats across the country.

“It is like trying to fly a plane and you have no speed gauge, you have no altimeter, you don’t know your elevation, you don’t know how far it is to the nearest airport. You have none of the information that you need,” says Susan Mayne, a former director of the Center for Food Safety and Applied Nutrition at the US Food and Drug Administration.

During his second term, President Donald Trump has made a concerted effort to shrink the US government. The US Department of Health and Human Services (HHS) has been one of his administration’s main targets. In March, the agency’s workforce fell from 82,000 employees to 62,000. Roughly 1100 additional layoffs were announced in October, though a court order temporarily paused these amid the ongoing government shutdown.

Most of the cuts have targeted staff in human resources, information technology and communications, but some have hit those running crucial public health surveys as well. HHS didn’t respond to New Scientist’s questions about the total number of layoffs, so it is unclear how many public health surveys have been affected and to what extent. So far, at least five have been impacted.

The National Survey on Drug Use and Health (NSDUH) was one of the first on the chopping block. In April, HHS terminated all 17 people running it, crippling the country’s only nationwide survey of drug use, addiction and mental health. For more than half a century, it has helped policymakers allocate funding to regions most afflicted by these problems. The latest report still came out in July, thanks to contractors from RTI International, an independent research institute tasked with collecting NSDUH data. But it isn’t clear what will happen next year. “Eventually all of the planning we did will run out. Who at HHS, then, will influence the direction of the survey?” said former NSDUH director Jennifer Hoenig in a social media post.

Then, in September, the government ended the Household Food Security reports, which monitor food insecurity throughout the country, claiming in a statement that “these redundant, costly, politicised and extraneous studies do nothing more than fear monger”.

However, the survey has received bipartisan support for decades, said Georgia Machell at the National WIC Association, a non-profit supporting the Special Supplemental Nutrition Program for Women, Infants and Children (WIC). This government programme provides low-income families with food assistance and nutrition education. “Programs like WIC rely on these national-level data to understand the broader picture of hunger and food insecurity in our nation, allowing resources to be directed where they are most needed,” said Machell in a statement.

Most recently, HHS gutted the National Center for Health Statistics (NCHS), terminating about 100 positions, according to the Data Foundation, a Washington DC-based non-profit organisation advocating for open data and evidence-informed policy. This includes most of the staff behind the National Vital Statistics System, which tracks births and deaths across the US and monitors the country’s leading causes of deaths and maternal mortality rates.

The entire team running the National Death Index was also affected, says former NCHS director Charles Rothwell. This little-known database contains identifying information about every death in the US, including the person’s name, place of residence, cause of death and, in many cases, their social security number, which allows for robust tracking. “This is the only dataset like this available,” says Rothwell.

Because it stores highly sensitive data, it doesn’t publish any reports. Instead, it assists other agencies and researchers conducting long-term studies, says Rothwell. For instance, the Department of Veterans Affairs works with its staff to compare deaths among veterans and non-veterans. Researchers outside of government also use it to confirm whether their participants have died or simply moved elsewhere. This is especially pertinent for long-term studies of older adults, such as the Health and Retirement Study, which monitors the well-being of ageing Americans. As such, a blow to the National Death Index will have knock-on effects across a range of public health surveys, says Rothwell.

HHS told New Scientist it “is not currently taking actions to implement or administer” the NCHS layoffs, citing the recent court order. However, it didn’t respond to questions about whether it would do so once the government shutdown ends, and if so, how it will maintain these databases.

Employees responsible for planning the National Health and Nutrition Examination Survey (NHANES) were also laid off in October. This survey is one of – if not the – most comprehensive assessments of health, diet and illness in the US. It deploys a fleet of mobile clinics to conduct blood and urine testing, bone density scans and oral health examinations to monitor diet, environmental exposures and the prevalence of illness nationwide. “It really sets the foundation for nutrition and public health policies,” says Mayne. For instance, it informs national dietary guidelines, environmental regulations and even updates on food labelling. “If we don’t know what is happening in the population with regard to health and nutrition, we don’t know where to prioritise our public health work,” she says.

HHS appears to have reversed terminations of NHANES staff, according to the Data Foundation. But the fact these positions were cut in the first place is deeply concerning – and the same goes for those working on other major public health surveys. These datasets steer public health policy in the US. Weaken or remove them, and the entire system could come crashing down.

ENVIRONMENT | OCT 28, 2025, 11:06 AM EDT | VIEW ON NEW SCIENTIST

Why Hurricane Melissa is one of the strongest Atlantic storms ever

The monster hurricane pummelling Jamaica is powered by abnormal sea surface temperatures in the Caribbean, which were made at least 500 times more likely by global warming

By Michael Le Page

A satellite image of Hurricane Melissa taken on 28 October

Associated Press / Alamy Stock Photo

Jamaica is being directly hit by what may be the strongest hurricane on record to make landfall in the Atlantic Ocean, forecast to produce up to a metre (40 inches) of rain over its mountains – and there is virtually no doubt that global warming has made Hurricane Melissa as strong as it is.

The warm waters that fuelled its intensification were 500 to 700 times more likely as a result of climate change, according to initial estimates by Daniel Gilford and his colleagues at Climate Central, a US non-profit organisation.

“The ‘500 to 700 times more likely’ number is big,” says Gilford. “It really illustrates how unlikely the extremely warm temperatures we are observing around Melissa would be without human-caused climate change.”

Tropical cyclones like Melissa are powered by warm water. The warmer the sea surface, the more water vapour forms as storms move over them. As moist, warm air rises, the water vapour starts to condense out, releasing latent heat. This warms the air and makes it rise higher, leading to more condensation and so on. This is the energy source that powers tropical cyclones.

In the central Caribbean where Melissa rapidly intensified to a Category 5 hurricane, sea surface temperatures are 1.4°C (2.5°F) higher than is typical for October. These abnormal temperatures also extend to an unusual depth, so there is a huge amount of extra heat energy in these waters.

This means that as Melissa churns up the sea and brings deeper waters to the surface, sea surface temperatures are remaining high. Where there is only a shallow layer of warm water, by contrast, colder waters are brought to the surface, cutting off a storm’s energy supply.

“There has been a perfect storm of conditions leading to the colossal strength of Hurricane Melissa: a warm ocean which has fuelled its rapid intensification over the last few days, but it is also moving slowly, meaning more rain can fall whilst it moves across land,” Leanne Archer at the University of Bristol, UK, said in a statement. “Most of these conditions have been supercharged by the extra heat in our oceans and atmosphere due to climate change.”

The combination of high winds and extreme rainfall could lead to catastrophic damage in Jamaica. Three people have already died preparing for the storm, which is expected to make landfall around 11am or 12pm local time.

“This is one of those worst-case scenarios,” Hannah Cloke at the University of Reading, UK, said in a statement. “The whole country will have a deep and permanent scar from this beast of a storm. It will be a long and exhausting recovery for those affected.”

Studies of previous disasters have shown that events such as this can reduce economic growth for decades afterwards. It had been suggested by economists that there can be rapid recovery, or even extra growth stimulated by recovery efforts, but these ideas have mostly turned out to be wrong.

HEALTH | OCT 27, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

Men may have to exercise more than women to get same heart benefits

Among over-50s, women seem to require less exercise than men to get the same reduction in heart disease risk, suggesting health guidelines need to be updated

By Christa Lesté-Lasserre

Exercise has significant benefits for heart health

Ian Canham/Alamy

Men over 50 may have to exercise more than twice as much as women to get the same heart health benefits. An analysis of activity tracker data found that men in this age group need nearly 9 hours per week of moderate to vigorous activity – like brisk walking or cycling – to gain a 30 per cent drop in coronary heart disease risk, compared with about 4 hours for women.

Scientists already suspected that women got more cardiac benefits than men based on self-reported exercise data, but such figures aren’t always accurate.

To overcome that problem, Jiajin Chen at Xiamen University in China and his colleagues retrieved data from wrist-worn activity trackers collected by the UK Biobank study and compared that with participants’ health records over a period of about eight years.

First, the team analysed information from 80,243 adults, with an average age of 61, who had no personal history of coronary heart disease. Among women, those who did at least 150 minutes of moderate to vigorous exercise per week saw a 22 per cent drop in their risk of developing coronary heart disease. For men, getting this amount of exercise was linked to just a 17 per cent drop.

Achieving a 30 per cent risk reduction required significantly more exercise – with a notable sex difference: 250 minutes for women, and 530 for men.

Then, the team looked at 5169 participants who had already been diagnosed with coronary heart disease. They had an average age of 67 and two-thirds of them were men. With 150 minutes of weekly moderate to vigorous exercise, women were 70 per cent less likely to die over the next roughly eight years – for any reason – than women who exercised less. By contrast, men who did 150 minutes of moderate to vigorous exercise each week were only about 20 per cent less likely to die than their less active counterparts.

“This isn’t bad news for men, it’s just something we should know about,” says Nir Eynon at Monash University, Australia. “Once we know, we can do better – we can do more exercise. And while it’s reassuring for women who are busy all the time, I also think women should not miss the fact that they need to exercise as well.”

Chen and his colleagues weren’t available for comment, but in their paper, they suggest the discrepancy may be explained by hormones, as higher oestrogen levels might enhance fat burning during exercise. It could also be related to biological differences that could mean women use more respiratory, metabolic and muscular strength to achieve the same physical tasks as men, says Eynon.

The study is “robust” and underscores the need for sex-specific guidelines, says Ersilia DeFilippis at Columbia University, New York City. A drawback, however, is that it is focused on a primarily well-off, well-educated population that was about 93 per cent white. Black women tend to have worse cardiovascular outcomes than white women, says DeFilippis, and social factors play a significant role in health and adherence to treatment plans.

“Understanding how these findings apply to a more racially diverse and socioeconomically disadvantaged population will be imperative in the future, given their higher burden of cardiovascular disease,” she says.

Even so, the findings in this older population suggest that even exercise later in life can have significant benefits – although activity should be tailored to people’s age and physical capacities, she adds. “It’s never too late to start moving and be more active.”

Journal reference:

Nature Cardiovascular Research DOI: 10.1038/s44161-025-00732-z

Technology

- Book Club: Read an extract from Every Version of You by Grace Chan: 2025 Oct 31

- Has life today been enshittified? Cory Doctorow's new book explores (paid): 2025 Oct 29

TECHNOLOGY | OCT 31, 2025, 5:30 AM EDT | VIEW ON NEW SCIENTIST

Book Club: Read an extract from Every Version of You by Grace Chan

In this passage from the opening of Grace Chan’s sci-fi novel, the November read for the New Scientist Book Club, we are introduced to her protagonists as they spend time in a virtual utopia which is becoming increasingly tempting in a dying world

By Grace Chan

As Every Version of You opens, New Year’s Eve is being celebrated in a virtual utopia

akinbostanci/Getty

The sky’s all wrong tonight. Oversaturated blue, it pixelates at the horizon into streaky seawater, and is hole-punched by the sun sinking towards its bloated reflection. The tide beats against the shore. One, two, three up the sand. One, two, three, four – leaving a sine wave of foam.

Tao-Yi sits with her legs folded beneath her, rotating a nearly empty beer bottle in her hands. Long shadows drip from the sandstone formations around her. In this tucked-away cove, shielded by ruddy cliffs, she can’t see the others, but she can hear them laughing and shouting as they gather driftwood for a bonfire.

She has let Navin drag her here, a little out of obligation, but mostly out of habit. It’s just what happens every New Year’s Eve – Zach throws a party. It would feel wrong to miss it.

The bottle stays ice-cold against her palms, impervious to her body heat. She lifts the rim to her lips. The last gulp slices down her throat. The ocean ruffles like a silk skirt in a breeze, creased and opaque. She waits for the gust to roll into shore, to lift tendrils of hair from her neck, but it never comes – the air in Gaia is as stale as a subway tunnel.

A rustle of sand grass heralds Navin’s approach. He’s almost a stranger – tall and lean in his short-sleeved shirt and khaki pants, black fringe falling choppily across his brow, a vulnerable smile. He holds out another bottle of beer.

“It tastes like shit,” she says, shaking her head. “It’s better than last year’s.”

She manages a smile, thinking of Zach’s experimental brew.

“Come back,” he insists, touching his fingers to her hairline. “Help us start the fire.”

Tao-Yi lets him pull her to her feet. She follows him out of the cove, skirting a cluster of boulders, and back along the shore. His shirt hangs loose on his frame, catching the bottom corners of his shoulder blades. She wants to touch those out-turned brackets, to assure herself of their realness.

Between the dunes and the sea, the others have filled a shallow pit with driftwood. There are a dozen or so capstone-educated twenty-somethings like herself and Navin, all sharp glances and witty repartee. Gen Virtual. They’re the lucky generation – born into motion, soaked with potential, cresting a wave of change.

Zach moves through the group easily, the others drawn to him like mosquitoes to shallow water. In an orange T-shirt and a knee-length sarong, he looks especially boyish. He leans over the driftwood, a lit match extended like a conductor’s baton between long brown fingers. The others whoop as flames blossom. There are no second attempts, if you follow the formula.

Tao-Yi summons her live interface. In the corner of her vision, a countdown glimmers neon: 9:00pm, 31 December 2087. 3 hours to go! A steady scroll of status updates overlays the beach scenery. Mostly snips, four-second video fragments dissolving as soon as she absorbs them into her attention: friends dancing at open-air concerts, go-karting under electronic fireworks, clinking stim shots to a backdrop of pounding beats.

Evelyn is walking over to her. Tao-Yi wills away the countdown and the snips. Tonight, her petite friend looks a little different. Although she’s wearing a pastel dress from her typical wardrobe, her dark brown hair is arranged in braids and her cheeks are decorated with gothic decals. It’s endearing, like a puppy trying to be edgy.

Evelyn bumps her hip against Tao-Yi’s. “Are you flash?” “I’m fine. Why?”

“You just seem quiet.”

Tao-Yi wraps her hands around her elbows, feeling the symmetrical indentations behind the bony joints. “Yeah, I’m just a bit spent. Busy day at work.”

“Oh yeah. Of course. You’re a hot shot Authenticity Consultant now.” Evelyn drags the syllables out and chuckles.

The title still sounds weird to Tao-Yi’s ears, even though she’s been at her job for half a year. She’s still getting her head around moving from a marketing gig, manipulating people into buying more stuff, to a place like Tru U, guiding lost souls back towards their true selves.

“People are just obsessed with their avatars. They want to make sure they look as unique as everyone else, you know.”

“Usoo, Tao-Yi, don’t pretend to be a cynic. I know you’re really a softie underneath,” Evelyn says. “Give it a few more months, and you’ll be spreading feel-good virus like your boss. What’s his name again? Andy? Gary?”

“Griffin. Not even close.”

“That’s right. You know what he said to me at that party you dragged me to last month? Wide eyes, straight face. You need to find your path.”

“Oh, yeah. He spouts that about ten times a day. My brain just filters him out now.”

“I told him I use Google Maps. He didn’t even crack a smile!”

Tao-Yi laughs. “He’s good at his job, though. Come in for an appointment?”

“No thanks – you lot can stay away from my virtual bits.”

Tao-Yi laughs again and turns towards the fire. Evelyn’s gaze wanders to Zach and stays there. The bonfire’s glow warms his tanned complexion, illuminating his gleaming black eyes and expressive mouth.

For a while, Tao-Yi watches Evelyn watching him. Then she slips away.

Every Version of You by Grace Chan (Verve Books) is the November 2025 read for the New Scientist Book Club. Sign up to read along with us here.

TECHNOLOGY | OCT 29, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

Has life today been enshittified? Cory Doctorow's new book explores

Enshittification is a term coined by Cory Doctorow in 2022. In his new book, Doctorow lays out how tech companies have made our lives progressively worse, finds Matthew Sparkes

By Matthew Sparkes

Does your phone seem less functional than it once was? It may be due to enshittification

HECTOR RETAMAL/AFP via Getty Images

Enshittification

Cory Doctorow (MCD Books)

“Enshittification” is one of those rare new words that so perfectly sums up a prevailing but innominate concept that it feels like it has existed forever, like “shrinkflation” or “greenwash” before it.

We are all painfully familiar with websites or apps enshittifying – that is, getting worse over time – as their owners squeeze users for profit. This can be seen everywhere from Instagram ditching a chronological stream of friends’ photos for algorithm-cobbled influencer nonsense to Apple preventing easy repairs and forcing you to buy a new handset.

Cory Doctorow coined the term in 2022 and has developed the idea in his latest book, Enshittification: Why everything suddenly got worse and what to do about it, which is also a call to action.

The playbook for enshittification is that a platform like Facebook sets up and offers a good service. It’s useful and fun, and people flock to it. The company then waits until we are reliant on it – our friends, neighbourhood groups, swimming clubs and schools are all there – and leaving is simply too much hassle.

By this point, the user base is so vast that advertisers are locked in, too. That’s when the firm starts to prioritise profits, making the service worse for users: more ads, more algorithms. Finally it squeezes its advertisers. The platform is now awful and toxic, works for nobody but shareholders and is impossible to leave. As Doctorow puts it, we are trapped in the rotting carcasses.

Years ago, the market would kill a bad company. If a café began to serve bad coffee, we would buy different coffee. But now tech firms carve out monopolies so profitable that they have huge resources to maintain them: buying competitors just to shut them down, lobbying politicians to weaken regulation and paying for exclusivity deals. (Did you know Google pays Apple $20 billion a year to make it the default search engine on Apple’s Safari browser?)

Enshittification lays bare the open secrets of the industry, such as the companies that allegedly collect so much personal data they know to charge more for stuff on payday because we are less likely to quibble. Or those that use algorithms to suppress wages in the gig economy, or create keystroke-monitoring systems that alert managers if we stop typing.

These distasteful snippets won’t all be new to readers, but, consumed in bulk, they leave a bad taste in the mouth. They will even make the savvy kick themselves for the numerous and varied ways they are being misled.

Yes, the tricks are just companies doing what they are designed to do: extract as much profit as possible. But computers, algorithms and the internet have enabled ever-craftier and more complex techniques that were impossible even a decade ago, and things are wildly out of hand.

Doctorow warns that the regulators that are supposed to protect us are often weaker than the companies they oversee. But he also places a lot of faith in them being the solution.

There have been positive moves in the European Union and the US under President Joe Biden, although there is a great deal more to be done, and tech firms can dream up ways to do us down faster than they can be stopped. We can demand more from our politicians, and well-designed legislation backed by regulators with teeth can have some effect.

What isn’t addressed, though, is the power of boycotting, and how tech firms need us more than we need them. It is completely possible to ditch social media, shop locally and use ethical search engines. And the more people who do it, the more likely it is that others will follow suit.

When it comes to travel, clothing or food, lots of us try to vote with our wallets. Maybe it is time more of us did it in the online world as well.

Space

- Sorry, but interstellar visitor 3I/ATLAS really is a comet, not aliens (paid): 2025 Oct 30

- The end of US support for the CMB-S4 telescope is devastating (paid): 2025 Oct 29

COMMENT SPACE | OCT 30, 2025, 3:00 PM EDT | VIEW ON NEW SCIENTIST

Sorry, but interstellar visitor 3I/ATLAS really is a comet, not aliens

Interstellar objects like 3I/ATLAS are exciting, but there is no reason to claim that they are evidence of alien spacecraft – sometimes a comet is just comet, says Robin George Andrews

By Robin George Andrews

Interstellar comet 3I/ATLAS as seen by the Gemini South telescope in Chile

International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist; J. Miller & M. Rodriguez (Intl Gemini Observatory/NSF NOIRLab), T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab)

The interstellar object 3I/ATLAS is, once again, doing something strange. This interloper from another star is currently concealed from view behind the sun, leading some people to wonder what it has to hide. There can only be one explanation, they whisper: it’s an alien spacecraft.

Except, of course, this is absolute rubbish. It makes no sense whatsoever for a spacecraft to obscure itself for just a few days, when it was plainly visible before and will be again. If this really is an alien ship hoping to remain incognito, either the extraterrestrials piloting it are remarkably stupid or they think we are.

How can I be so sure? Well, to paraphrase something an astronomer told me recently: if this really is a spaceship, it’s done a bloody good job at camouflaging itself as a comet. That is what makes the clickbait discourse about 3I/ATLAS (named after the eagle-eyed planetary-defence apparatus that spied it in July) both frustrating and unintentionally hilarious. It’s so patently, screamingly obvious that it’s a comet.

Let’s tick off the reasons why. It has a coma, an envelope of vaporised ices, surrounding it. It has a glittering tail. It is moving on a trajectory that can be best explained if it is an icy projectile entering the solar system from elsewhere. Oh, and the reason why it is “hiding” behind the sun? That’s because it has just reached perihelion, the closest point to our home star on its tour of our planetary neighbourhood. All spacefaring voyagers – from planets and comets to asteroids – have perihelions; 3I/ATLAS just happens to be nearest to the sun while it is behind it, from Earth’s point of view.

Sure, there are some odd things about 3I/ATLAS that are getting astronomers excited. For one, it has a lot more carbon dioxide ice in it than water ice. But that still makes it a comet, not a space probe. It also has both nickel and iron in it, which – wait a minute, those are metals! Spaceships are made of metals! Does that mean 3I/ATLAS actually is a spaceship after all? No – we see metals inside the rocky-icy mudball cores of comets all the time. In fact, our own solar system’s comets come in a variety of flavors, and some of them are quite weird.

That 3I/ATLAS at one point had a dusty tail pointing towards the sun, rather than away from it, was also a little unusual. Some suggested that it wasn’t a tail at all, but rather a thruster plume on a spaceship trying to decelerate. The problem is that 3I/ATLAS’s trajectory is consistent with an interstellar comet, not someone slamming on the brakes of their interstellar spacecraft. Its peculiar tail direction was due to the type of icy-dusty particles being blasted off its surface. This ephemera is usually pushed away from the sun by solar radiation pressure, but some of this cometary dandruff was so heavy that it couldn’t be pushed backwards and instead tumbled towards the sun.

3I/ATLAS is only the third interstellar object ever observed, so you would expect to find some anomalous features when perusing such a small population. The first known interstellar object, ‘Oumuamua, was far stranger: it was probably cigar-shaped and it rapidly accelerated as it left the solar system. Although bizarre, it was nevertheless perfectly explicable as a flamboyant comet-like object. Both 2I/Borisov and 3I/ATLAS, the next two interstellar objects, also have their share of curious features. But suggesting they aren’t comets, but spacecraft, would be like referring to the ice cubes in your freezer as pineapples. You are welcome to do it, but you are going to need to provide a lot more evidence if you want to convince me.

Many of us, myself included, anxiously yearn for the day we discover that we aren’t alone in the universe, so I don’t find it surprising that people have leapt on the (unfounded) idea that 3I/ATLAS could be a sign this day has finally arrived. But in an era infested by misinformation, to suggest this comet might be aliens, in the face of all evidence, isn’t just silly – it’s deeply irresponsible.

COLUMNIST SPACE | OCT 29, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

The end of US support for the CMB-S4 telescope is devastating

The US government's decision to stop supporting a telescope facility that would have given us unprecedented insight into the early universe is calamitous, says Chanda Prescod-Weinstein

By Chanda Prescod-Weinstein

The South Pole Telescope, which CMB-S4 would have used to measure variations in the temperature and polarisation of microwave light across most of the sky.

Brad Benson, University of Chicago, Fermilab

Robert Frost’s poem The Road Not Taken opens with “Two roads diverged in a yellow wood,/ And sorry I could not travel both”.

These lines come to mind when I consider the US government’s public letter of 9 July stating that it would no longer support the CMB-S4 project. CMB-S4, short for Cosmic Microwave Background-Stage 4, was meant to be a next-generation, multi-continental telescope facility that would have given all of humanity unprecedented insight into the earliest light to ever fly free through the cosmos.

In the beginning, the universe was full of a dense particle-plasma stew. The plasma was so dense that particles of light, photons, couldn’t go very far without running into something. As well as being thick, the stew was very hot, which prevented the formation of phenomena like atoms. Only after the universe had experienced cosmic inflation, where space-time expanded rapidly for an almost negligible fraction of a second, did it cool off enough for the first hydrogen atoms to form. Once this kind of clumping became possible, photons had room to manoeuvre and began to fly across space-time.

It was 61 years ago that humanity first learned we were awash in these photons, which came to be known as the cosmic microwave background radiation. What seemed like a bit of background noise in a radio signal turned out to be a messenger from the early cosmos. For decades, we have scrutinised these photons: their wavelength (and associated temperature), their intensity and their variation across space.

The CMB is almost a literal gold mine, in the sense that it provides a lot of information about where everything we can see came from, including the stars whose explosions make gold. If we scan the entire sky and look at the temperature associated with the photons, we see small variations in the temperature. Their locations are random, but the size of the variation is consistent across them all.

Our best cosmological theory tells us that these fluctuations are the result of little quantum variations in how much stuff there was at any given location at the moment the photons went free. Places where there was a little bit more were essentially the starting point of gas that gravitationally accumulated into protostars, which became stars that clustered together into what eventually became galaxies. So, those little variations in the CMB are the beginning of us.

“ The pullback from the project is part of the US’s reckless retreat from global science collaboration “

Perhaps the single most important measurement we have done of the CMB is characterising how these temperature variations correlate with physical scale. We can ask how many of the variations are due to effects on larger scales or smaller scales, knowing that certain physical phenomena happen at longer distances and others at shorter ones. In other words, different moments in cosmological history are imprinted on the CMB.

For example, we can “see” when the universe became transparent to matter – that first moment when hydrogen formed, an instant known as recombination. We can also “see” how much dark matter and dark energy there is in the universe, even though they are invisible to us. Their existence is imprinted on the CMB.

CMB-S4 was supposed to be the next step in uncovering all of the lessons that the CMB has to teach us. One major goal was to look for evidence of primordial gravitational waves – ripples in space-time caused by cosmic inflation. “Inflation” is really a class of models, and we know that, broadly, they all give the right physics for our universe. But we are still unsure about the details. Because inflation happened in the universe’s earliest moments, imprints of gravitational waves on the CMB are likely to be the best way to distinguish between inflationary models.

The end of governmental support for CMB-S4 is like putting a stick in your own bicycle wheel: we were flying along, joyfully studying the cosmos, and now we have been thrown entirely. The impact will be felt globally too. Historically, the US has invested more into cosmological science than most nations, which is one reason why students from around the world come to the US to study. The data from US-funded experiments has also often become a global resource, so the pullback from this project, which already seemed likely under the previous presidential administration, is now part of the US’s reckless retreat from global collaboration.

Frost ends his poem by talking about his choice of road: “I took the one less traveled by,/ And that has made all the difference.” It is so unfortunate that, when it comes to CMB science, the US decided not to take the road less travelled. It will certainly make a difference, but not for the better.

Chanda’s week

What I’m reading

I have been enjoying Niayesh Afshordi and Phil Halper’s Battle of the Big Bang: The new tales of our cosmic origins.

What I’m watching

I have been rewatching DC Universe films that feature Harley Quinn, a personal favourite.

What I’m working on

I have been trying to capture good images of the Andromeda galaxy from my backyard.

Life

- Cats revealed in all their glory in stunning new photographs: 2025 Oct 29

LIFE | OCT 29, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

Cats revealed in all their glory in stunning new photographs

Photographer Tim Flach's new book Feline explores the mysterious and irresistible world of cats, from the domesticated to the wild, and why we love them

By David Stock

A Cornish Rex cat named Stella

Tim Flach

Cats are distinctive animals: domesticated for centuries, revered and reviled in equal measure throughout history and bred to match our own aesthetic tastes and whims.  From a sensational internet fluffball to his own domestic longhair Loki, renowned animal photographer Tim Flach explores the world of cats in his new book Feline, showing how intertwined our lives have become.

“At the heart of this project was to unmask the essence of feline,” says Flach. Including more than 170 of Flach’s cat images, Feline also sees neuroscientist Morten Kringelbach explore why we find felines so compelling, and evolutionary biologist Jonathan Losos delve into the species and its evolution.

Link to video: https://www.youtube.com/watch?v=9HPKxLbx7m8

Pictured above is Stella, a Cornish Rex from Montreal, Canada, whose striking appearance is a result of genetic quirks during her embryonic development. Cats with different-coloured eyes almost always have one blue eye, writes Losos. The phenomenon is particularly common in entirely white cats.

Flach also includes shots of feline internet sensations such as Atchoum, below, a long-haired Persian with a rare condition called hypertrichosis, which causes his hair to grow profusely. Currently, Atchoum has more than 900,000 followers on Instagram.

Atchoum, a Persian cat with hypertrichosis

Tim Flach

Elsewhere, Zuu, an exotic shorthair, takes cuteness to the extreme – a perfectly round fluffball that’s impossible to resist (below).

An exotic shorthair cat named Zuu

Tim Flach

Cuteness, writes Kringelbach in Feline, is how mammalian and avian babies elicit care from elders, compensating for their helplessness. Big eyes, rounded features and large heads are typical baby features that humans (and many other species) find irresistible, and have been shown to trigger activity in the orbitofrontal cortex, an emotion-processing region of the brain. The idea is that if our brains reward us for looking at and providing for babies, it makes it easier for our species to survive. But this response is not restricted to our own species. Cats, too, trigger this same reward zone in humans.

Oriental shorthair kittens

Tim Flach

By scanning his own brain as it responds to Loki, his domestic longhair, Flach highlights the cuteness effect and how his orbitofrontal cortex lights up within 130 milliseconds, much faster than conscious thought. “In a way, at some fundamental level, you can see how cuteness is unfolding,” he says.

But cuteness is just one of cats’ evolutionary advantages.  They are perfectly adapted for a life of hunting – as demonstrated by this 8-week Sphynx cat Valentine, below, which is leaping for a cat toy just out of sight.

A Sphynx cat leaps for its prey (a toy)

Tim Flach

A cat’s nose has as many as 40 times more scent-detecting cells than a human’s. Cats’ whiskers are finely tuned to detect subtle vibrations, helpful for moving in the dark and hunting at close range. Their tongues, too, are uniquely fashioned. Covering the organ are small papillae, or spikes, made of keratin – the same material as in our nails and hair.  This roughness is useful in grooming, eating and drinking. But the tongue also plays a role in cats’ sense of smell, transferring pheromone scents to the vomeronasal, or Jacobson’s, organ at the roof of the mouth.

Poppy the domestic shorthair cat shows off her tongue

Tim Flach

But it is cats’ eyes that are perhaps their most alluring feature. In the past, superstition suggested that a cat’s bright eyes were indicative of a devil glowing back. In reality, the glowing orbs that shine back at you if you point a light at a cat in the dark are the result of special reflective cells known as tapetum lucidum, which reflect unabsorbed light back to the photoreceptors (rods and cones) in the retina. Cats have a much greater density of rods than humans, and are also able to widely dilate their pupils, enabling them to see at light levels six times lower than humans, writes Losos in his book.

The eye of Smirnoff, a Russian Blue cat

To capture cats’ eyes for Feline, Flach and his team used special lenses and high-speed flash to show them in ways never before seen, to “show it almost like a lighthouse light, like a mirror”, says Flach.

Table of Contents

New Scientist: 2025 Oct 31

Features

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Men may have to exercise more than women to get same heart benefits: 2025 Oct 27

Technology

Book Club: Read an extract from Every Version of You by Grace Chan: 2025 Oct 31

Has life today been enshittified? Cory Doctorow's new book explores (paid): 2025 Oct 29

Space

Sorry, but interstellar visitor 3I/ATLAS really is a comet, not aliens (paid): 2025 Oct 30

The end of US support for the CMB-S4 telescope is devastating (paid): 2025 Oct 29

Life

Cats revealed in all their glory in stunning new photographs: 2025 Oct 29