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- Why are the physical constants of the universe so perfect for life? (paid): 2025 Jun 23

- How metaphysics probes hidden assumptions to make sense of reality (paid): 2025 Jun 23

- Why geoengineering is no longer a complete taboo for scientists (paid): 2025 Jun 23

- Why physicists think geometry is the path to a theory of everything (paid): 2025 Jun 23

- The deep lessons quasiparticles teach us about the nature of reality (paid): 2025 Jun 23

- Ancient humans only evolved language once, but why? (paid): 2025 Jun 23

SPACE | JUN 23, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

Why are the physical constants of the universe so perfect for life?

Conditions in our little pocket of the universe seem to be just right for life - and the much-debated anthropic principle forces us to wonder why

By Leah Crane

Denys Bilytskyi/Alamy

When we look out into the universe, we know it can support life – if it couldn’t, we wouldn’t exist. This has been stated in different ways over the years, but the essential thrust makes up the core of a philosophical argument known as the anthropic principle. It sounds obvious, even tautological, but it isn’t quite as simple as that.

This story is part of our Concepts Special, in which we reveal how experts think about some of the most mind-blowing ideas in science. Read more here

To get your head around it, start with what scientists call the fine-tuning problem, the fact our universe seems perfectly balanced on the knife’s edge of habitability. Many fundamental constants, from the mass of a neutron to the strength of gravity, must have very specific values for life to be possible. “Some of these constants, if you make them too large, you just destabilise every atom,” says Luke Barnes at Western Sydney University in Australia.

The anthropic principle began as an attempt to explain why the universe is in this seemingly improbable state, and it boils down to a simple idea: the universe has to be this way, or else we wouldn’t be here to observe it.

There are two main formulations of the principle, both of which were set out in a 1986 book by cosmologist-mathematicians John Barrow and Frank Tipler. The weak principle states that because life exists, the universe’s fundamental constants are – at least here and now – in the range that allows life to develop. The strong principle adds the powerful statement that the fundamental constants must have values in that range because they are consistent with life existing. The “must” is important, as it can be taken as implying that the universe exists in order to support life.

If the weak principle is “I heard a tree fall in the forest, and therefore I must be in a place where trees can grow”, the strong principle says “A tree has fallen nearby, and therefore this planet was destined to have forests all along.”

For scientists today, the weak anthropic principle serves as a reminder of possible biases in observations of the cosmos, particularly if it isn’t the same everywhere. “If we live in a universe that is different from place to place, then we will naturally find ourselves in a place that has some specific conditions conducive to life,” says Sean Carroll at Johns Hopkins University in Maryland.

As for the strong version of the principle, there are physicists who consider it useful too, Barnes among them. He works on developing different flavours of multiverse models and sees the strong principle as a handy guide. It implies that, within a multiverse, there is a 100 per cent chance of at least one universe forming that is conducive to life. So, for any given multiverse model, the closer that chance is to 100 per cent, the more plausible it is. If the probability is, say, around 50 per cent, Barnes sees that as a good omen for the model’s veracity. “But if it’s one-in-a-squillion, then that’s a problem,” he says.

In truth, however, most physicists write off the strong principle as simply too strong. It suggests the universe is deterministic; that life was always certain to emerge, according to Elliott Sober at the University of Wisconsin–Madison. “But that probability could have been tiny and life could have still arisen, and the observations would be the same.”

Where does that leave us? The strong principle does, on the surface, provide an answer to the fine-tuning problem – but that answer is widely considered unreasonable. On the other hand, while the weak principle doesn’t provide a reason why the constants of our universe are so finely tuned, it is a useful tool for researchers. As principles go, this one is rather slippery.

Read the other stories in this series using the links below:

Ancient humans only evolved language once, but why?

What is a mindset and can you cultivate a better one?

The deep lessons quasiparticles teach us about the nature of reality

Why geoengineering is no longer a complete taboo for scientists

How the science of friendships can help make yours better

Why physicists think geometry is the path to a theory of everything

Why you should assume that even the simplest animals are conscious

How quantum superposition forces us to confront what is truly real

How symbiosis made Earth what it is – and why it’s key to our future

At last, we are discovering what quantum computers will be useful for

How metaphysics probes hidden assumptions to make sense of reality

PHYSICS | JUN 23, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

How metaphysics probes hidden assumptions to make sense of reality

All of us hold metaphysical beliefs, whether we realise it or not. Learning to question them is spurring progress on some of the hardest questions in physics

By Daniel Cossins

Matt Sheumack/Alamy

Metaphysics has something of an iffy reputation. “I think a lot of people think it’s a complete waste of time,” says philosopher Stephen Mumford at the University of Durham, UK, author of Metaphysics: A very short introduction. “They think it’s all just arguing over pointless questions, like, classically, how many angels could dance on the head of a pin?”

It isn’t difficult to see why. Classical metaphysics – the term comes from the Greek “meta”, meaning beyond – does ponder some bizarre-sounding questions. What is a table, for instance? What form of existence do colours have? In addition, it does so through reasoning alone, with tools such as “reductio ad absurdum” – a mode of argumentation that seeks to prove a claim by deriving an absurdity from its denial. It is a far cry from the empirical knowledge scientists pursue through observation and experiment.

This story is part of our Concepts Special, in which we reveal how experts think about some of the most mind-blowing ideas in science. Read more here

But the idea that metaphysics is all just abstract theorising with no basis in reality is a misconception, says Mumford: “Metaphysics is about the fundamental structure of reality beyond the appearances. It’s about that part of reality that can’t be known empirically.”

Indeed, as modern science has expanded its reach into territories that were once seen as the purview of metaphysics, such as the nature of consciousness or the meaning of quantum mechanics, it has become increasingly clear that one can’t succeed without the other.

To see why, the first thing to understand is that everyone has metaphysical beliefs, says Vanessa Seifert, a philosopher of science at the University of Bristol, UK. You probably believe objects exist when we aren’t looking at them, for instance, even though there is no hard and fast empirical evidence that this is true.

It is also important to recognise that there is such a thing as “naturalised metaphysics”, which is distinct from classical metaphysics in that it is informed by science, says Seifert. “You look at what science tells us about the world, and you investigate how literally you can take that.”

This brand of metaphysics provides a vital service for science because it examines the assumptions underlying our attempts to understand the world. “In many cases, metaphysical beliefs are the fundamental bedrock upon which empirical knowledge is built,” says Mumford.

Take causation – the idea that effects have causes – which we all believe despite the fact that causal connections aren’t observable. “Basically, the whole of science is premised on this metaphysical notion of causation,” he says.

These days, scientists routinely grapple with all manner of other concepts that are deeply infused with the metaphysical. From chemical elements, space and time to the concept of species and the laws of nature themselves – plus loads more.

We have a choice, says Mumford. We can either scrutinise our metaphysical beliefs for their coherence or ignore them. “But in the latter case, we’re just assuming them unreflectively,” he says.

One of the most striking cases in which science and metaphysics collide is quantum mechanics, which describes the world of atoms and particles. It is a hugely successful scientific theory, yet when grappling with its meaning, physicists must confront metaphysical questions, like how we should interpret quantum superpositions, the apparent ability of a quantum system to exist in multiple states simultaneously.

Here, all we have are competing interpretations of what is actually going on that won’t submit to experimental testing, and it is becoming clear that progress will be impossible without confronting our hidden assumptions. To do so, some researchers have recently begun to revive a tradition known as “experimental metaphysics”, in which they test the coherence of the metaphysical beliefs underlying the various interpretations of quantum theory.

“In the end, you can’t do physics without metaphysics,” says Eric Cavalcanti at Griffith University in Brisbane, Australia, one of the foremost proponents of this approach. “You have to deal with both at the same time.”

Read the other stories in this series using the links below:

Ancient humans only evolved language once, but why?

Why are the physical constants of the universe so perfect for life?

What is a mindset and can you cultivate a better one?

The deep lessons quasiparticles teach us about the nature of reality

Why geoengineering is no longer a complete taboo for scientists

How the science of friendships can help make yours better

Why physicists think geometry is the path to a theory of everything

Why you should assume that even the simplest animals are conscious

How quantum superposition forces us to confront what is truly real

How symbiosis made Earth what it is – and why it’s key to our future

At last, we are discovering what quantum computers will be useful for

EARTH | JUN 23, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

Why geoengineering is no longer a complete taboo for scientists

Geoengineering comes in many forms and the risks and potential benefits vary widely. But many researchers now feel it’s time to investigate this controversial idea

By Madeleine Cuff

mdesigner125/iStockphoto/Getty Images

We know the only safe and long-term solution to climate change is cutting our greenhouse gas emissions. But in the face of still-rising emissions and escalating climate impacts, some are considering an option that – until recently – would never have escaped a researcher’s lips without a good deal of trepidation.

This story is part of our Concepts Special, in which we reveal how experts think about some of the most mind-blowing ideas in science. Read more here

“Geoengineering” is a catch-all term used to describe human interventions in climate systems, generally with the intention of preserving ecosystems or cooling the planet. But defining what counts as geoengineering is tricky. At its most broad, it can capture anything from planting trees to propping up ice sheets with giant underwater curtains.

Some geoengineering ideas are more contentious than others. Large-scale reforestation, when done right, is widely accepted as a positive climate action. But more extreme ideas, such as modifying the way sunlight behaves in Earth’s atmosphere, cause more concern.

It is “different levels of risk and return”, says Janice Lachance at the non-profit American Geophysical Union (AGU), which recently drew up an “ethical framework” for scientists working in this space. “Planting trees in a park… will probably be very quick, very noncontroversial,” she says. “However, it quickly changes when you start thinking about new technologies, new ways of doing things.”

Take the idea of reflecting more sunlight back into space to cool the planet, known as solar radiation management (SRM). This could potentially be done in three basic ways (see graphic below), and most modelling studies suggest the technique could provide some cooling effect within a few years of first deployment, although it might also cause substantial disruption to rainfall cycles and cloud formation.

SRM has long been a taboo research topic, but as temperatures continue to rise and climate impacts become increasingly severe, it is attracting more attention from scientists, governments and philanthropists.

Some activists say we should stay well away from even researching this kind of intervention, warning it risks distracting people from the need to rapidly cut emissions. But Andy Parker at The Degrees Initiative, a nongovernmental organisation focused on SRM, warns emissions cuts are no longer enough for humanity to cope with the impacts of climate change.

He says we “need to consider how we manage risks from greenhouse gases we’ve already emitted”. Plus, without international research and discussion on geoengineering, there is an increasing risk that a “rogue actor”, such as a country suffering acute climate impacts, could decide to unilaterally start geoengineering.

Against this backdrop, a growing number of scientists now support research into geoengineering strategies. “There’s a recognition among some scientists that we are not doing well in meeting the goals of the Paris Agreement,” says Lachance. That is what prompted the AGU to compile its ethical framework to steer research on climate interventions.

It isn’t just how research is conducted that has people worried – who conducts it is also a pressing concern. Planetary-scale geoengineering ideas often put lower-income countries, particularly those around the equator, on the frontline of unintended consequences, such as disruption to monsoon patterns. But most of the research into geoengineering techniques happens in higher-income nations, with less skin in the game.

As part of The Degrees Initiative, Parker is working with researchers across poorer countries in the southern hemisphere to build research capacity in SRM, with the hope that it will ensure any future decision on deployment is influenced by those who have the most at stake. “We’ve got no position on whether SRM is ever used or not,” he says. “But we do think that developing countries need an informed voice to do their own research.”

Read the other stories in this series using the links below:

Ancient humans only evolved language once, but why?

Why are the physical constants of the universe so perfect for life?

What is a mindset and can you cultivate a better one?

The deep lessons quasiparticles teach us about the nature of reality

How the science of friendships can help make yours better

Why physicists think geometry is the path to a theory of everything

Why you should assume that even the simplest animals are conscious

How quantum superposition forces us to confront what is truly real

How symbiosis made Earth what it is – and why it’s key to our future

At last, we are discovering what quantum computers will be useful for

How metaphysics probes hidden assumptions to make sense of reality

MATHEMATICS | JUN 23, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

Why physicists think geometry is the path to a theory of everything

From four-dimensional hexagons to the mind-bending amplituhedron, geometrical shapes are wilder than we learn at school - and they are a crucial tool for understanding reality

By Michael Brooks

Yu Siang-Teo/Unsplash

Can you imagine the imprint a four-dimensional hexagon might leave as it passes through your three-dimensional kitchen table? Probably not, but some people can.

One such person was mathematician Alicia Boole Stott, daughter of logician George Boole. Early in the 20th century, she made models of the shapes four-dimensional objects would create when passing through three-dimensional objects. Decades later, when mathematicians could check such things using computer programs, they found Boole Stott had possessed an uncanny gift for getting these shapes right.

This story is part of our Concepts Special, in which we reveal how experts think about some of the most mind-blowing ideas in science. Read more here

For most of us, geometry conjures up thoughts of pencils, rulers, triangles and circles. It means those complicated questions you got asked at school involving parallel lines and angles. But as Boole Stott’s story shows, researchers have been taking geometry way beyond this for some time.

Geometry can stray far from the comprehensible world of two- and three-dimensional shapes – and in so doing, it can be extremely illuminating. Perhaps the best example is general relativity, Albert Einstein’s theory of gravity, which joins the three dimensions of space with time, creating a four-dimensional stage on which everything in the universe plays out.

But geometry can also make use of dimensions that aren’t physically real. Think of meteorology, for instance, where a point in the atmosphere can have many “dimensions” – latitude, longitude, temperature, pressure, wind speed and so on.

Researchers map these dimensions as shapes that extend into higher dimensions to help understand the workings of the atmosphere. “From things like this, you can apply mathematical models and actually work out what happens to [those properties] in many dimensions,” says mathematician Snezana Lawrence at Middlesex University in London.

For theoretical physicists, extra dimensions seem to be a necessary part of any full description of the universe, with some proposing that our reality is a “projection” from a higher dimension, for instance. This may sound outlandish, but if physicists make certain simplifying assumptions related to this idea, it suddenly makes it possible to carry out calculations to do with fundamental particles and black holes that are otherwise impossible.

Some physicists are banking on even stranger geometrical ideas being a route to a “theory of everything”, a single framework that explains the cosmos and everything in it. One of these is the “amplituhedron”, a mathematical object developed by Jaroslav Trnka at the University of California, Davis, and Nima Arkani-Hamed at the Institute for Advanced Study, New Jersey. Think of this as an abstract, multi-dimensional crystal, the properties of which provide an alternative way of describing the fundamentals of particle physics.

Or there is “causal dynamical triangulation”, developed by Renate Loll at Radboud University in the Netherlands. This stitches together an ensemble of geometrical shapes to create a description of space-time that seems to have some of the properties of both quantum theory and general relativity – two ideas that are normally incompatible. It is, she says, not just an abstract geometrical notion, but a testable reflection of the universe’s real properties that could be mirrored in our observations of the cosmic microwave background radiation that fills the whole of space.

Neither of these ideas yet amount to a theory of everything. But some suspect that to have any hope of finding one, we need a fresh vision for physics – and there is an increasing sense that this might be written in the language of geometry. Whether that is true or not, geometry is definitely more than hexagons – even four-dimensional ones.

Read the other stories in this series using the links below:

Ancient humans only evolved language once, but why?

Why are the physical constants of the universe so perfect for life?

What is a mindset and can you cultivate a better one?

The deep lessons quasiparticles teach us about the nature of reality

Why geoengineering is no longer a complete taboo for scientists

How the science of friendships can help make yours better

Why you should assume that even the simplest animals are conscious

How quantum superposition forces us to confront what is truly real

How symbiosis made Earth what it is – and why it’s key to our future

At last, we are discovering what quantum computers will be useful for

How metaphysics probes hidden assumptions to make sense of reality

PHYSICS | JUN 23, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

The deep lessons quasiparticles teach us about the nature of reality

We have discovered legions of strange particles that seem to only have a ghostly existence inside materials. Even so, they are the basis of much modern technology - so are they actually real?

By Daniel Cossins

koto_feja/Getty Images

koto_feja/Getty Images

When we think of particles, we tend to think of them as real objects – tiny, point-like entities with definite properties such as position or speed. But particles are really just energetic spikes in the underlying fields that permeate the universe, which themselves can’t be observed directly. All of which can get a bit confusing.

This story is part of our Concepts Special, in which we reveal how experts think about some of the most mind-blowing ideas in science. Read more here

And yet deeper bafflement awaits when you consider the existence of quasiparticles, which emerge from the complex interactions between the “fundamental” particles in solids, liquids and plasmas. They boast near-magical properties that promise exotic new materials and technologies, while forcing us to confront some of our deeply held beliefs about particles in general.

“They very much muddy the waters when it comes to the question of what is a particle,” says Douglas Natelson at Rice University in Houston, Texas. A quasiparticle is “some kind of excitation in a material that has many of the properties you think of as being particle-like”, he says. They can have a reasonably well-defined position and velocity. They can have charge. They can carry energy. Why, then, are they only quasiparticles and not real particles?

It comes down to them existing only inside matter. Natelson compares it to spectators doing “the wave” in a stadium. “We can look at the wave and say ‘Oh, look! There’s a wave, it’s about so big and it’s travelling at a certain speed.’ But the wave is actually this collective thing made up of the behaviour of all of the fans in the stadium.”

To coax quasiparticles into existence, physicists take an object, such as a piece of metal, and subject it to extreme temperatures or pressures or magnetic fields. Then they observe the collective behaviour of the particles within.

One of the first of these strange phenomena was discovered in the 1940s. It was a “hole”: the absence of a negatively charged electron where one should exist. These holes hop around inside solids like positively charged particles, and by treating them as independent entities, researchers were able to create the semiconductors that now power laptops and smartphones.

“Basically, all of modern electronics is based on electrons and holes,” says Leon Balents at the University of California, Santa Barbara. “We make use of these quasiparticles all the time.”

In the intervening decades, we have discovered a whole zoo of exotic quasiparticles. There are magnons, emerging from waves in spin, the quantum property that is the basis of magnetism. There are Cooper pairs, which emerge at low temperatures and carry electrical charge with no resistance in superconductors. The list goes on. And, indeed, it continues to grow as physicists predict and observe even weirder species with strange-sounding names, including pi-tons, fractons and even wrinklons.

One of the most exciting, says Balents, are non-Abelian anyons. Unlike other particles we know of, these quasiparticles can, in effect, remember how they have been manipulated – a property that makes them a tantalising proposition for use in quantum computers.

“The jury’s still out on whether they’ll actually be useful,” says Balents. Nevertheless, Microsoft and other major corporations are investing heavily in quasiparticle research.

The other reason quasiparticles are so fascinating takes us back to the question of what a particle is. If quasiparticles have particle-like properties, then we have to consider that the “fundamental” particles from whose interactions they arise – your electrons, photons and quarks – may themselves emerge from something deeper.

“Are the things that we think of as fundamental particles really fundamental, or are they somehow quasiparticles of some underlying fundamental theory?” says Natelson. “Is it elephants all the way down?”

Read the other stories in this series using the links below:

Ancient humans only evolved language once, but why?

Why are the physical constants of the universe so perfect for life?

What is a mindset and can you cultivate a better one?

Why geoengineering is no longer a complete taboo for scientists

How the science of friendships can help make yours better

Why physicists think geometry is the path to a theory of everything

Why you should assume that even the simplest animals are conscious

How quantum superposition forces us to confront what is truly real

How symbiosis made Earth what it is – and why it’s key to our future

At last, we are discovering what quantum computers will be useful for

How metaphysics probes hidden assumptions to make sense of reality

HUMANS | JUN 23, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

Ancient humans only evolved language once, but why?

There’s an argument rumbling about why our ancestors evolved language. And surprisingly, one of the possible explanations has nothing to do with communication

By Colin Barras

Adobe Stock

My son is a wizard. He walks into the kitchen, looks at me and utters the magic words: “Can I have a cheese and tomato sandwich, please?” A few minutes later, just such a snack appears in front of him.

Other young animals can communicate their desire for food through grunts, tweets and growls. But only humans have the sophisticated system of grammar and vocabulary that allows us to communicate in precise terms.

This story is part of our Concepts Special, in which we reveal how experts think about some of the most mind-blowing ideas in science. Read more here

In fact, with studies of animals increasingly showing that they share many characteristics once thought to be the preserve of humans – from culture to emotions and even morality – language may seem like the one thing that truly sets us apart. “I think language makes us feel special as a species,” says Brian Lerch at the University of North Carolina at Chapel Hill.

Given all that, one of the key things researchers want to know about language is how it evolved, and why it only did so in our human lineage.

Psychologist Shimon Edelman at Cornell University in New York state thinks language’s magical power has a fairly straightforward evolutionary explanation. With his colleague Oren Kolodny, now at the Hebrew University of Jerusalem, he argues that it may have emerged 1.7 million years ago, when ancient humans began making stone hand-axes that are beyond the ability of non-human animals to produce.

The idea is that novice tool-makers would have required guidance from an expert to make their own hand-axes, so tool-making sites became classrooms. Proto-language might have emerged as a way for teachers to communicate to students – which could explain why both language and tool-making seem to require the brain to arrange and order thoughts into structured sequences.

But about a decade ago, a key experiment challenged that view. In 2014, Shelby Putt at Illinois State University and her colleagues tasked 24 volunteers with learning to make hand-axes from an expert who either talked them through the process or merely made the tools in the volunteers’ presence while occasionally pointing to direct their attention. Surprisingly, both methods were effective, suggesting verbal language isn’t necessary for complex tool-making.

This doesn’t mean Putt sees language and tool-making as completely unconnected. She thinks complex tool-making really did require humans to arrange and order their thoughts to stay on task. This, she argues, led to the expansion of the brain regions involved in working memory, which we use to briefly hold and manipulate ideas.

But Putt suspects it was only at some later date that humans used this ability to structure and order their thoughts to develop language – presumably because it helped them communicate better and boosted their chances of survival.

These scenarios all assume that language is fundamentally a tool for communicating with others. But that might not be the case. A third way to think about the evolution of language focuses almost exclusively on the way it can help individuals “talk” to themselves and organise their thoughts to undertake complex tasks.

According to some, including the influential linguist Noam Chomsky, this is what drove the evolution of language, meaning it had nothing at all to do with tool-making. Instead, these researchers think language emerged as recently as 70,000 years ago, perhaps simply because of a random genetic mutation that prompted brain rewiring.

Truth be told, there is still little consensus about quite how language arose. But if Chomsky and his ilk are right, though it didn’t involve magic, it might at least have involved a little luck.

Read the other stories in this series using the links below:

Why are the physical constants of the universe so perfect for life?

What is a mindset and can you cultivate a better one?

The deep lessons quasiparticles teach us about the nature of reality

Why geoengineering is no longer a complete taboo for scientists

How the science of friendships can help make yours better

Why physicists think geometry is the path to a theory of everything

Why you should assume that even the simplest animals are conscious

How quantum superposition forces us to confront what is truly real

How symbiosis made Earth what it is – and why it’s key to our future

At last, we are discovering what quantum computers will be useful for

How metaphysics probes hidden assumptions to make sense of reality

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TECHNOLOGY | JUN 27, 2025, 3:00 PM EDT | VIEW ON NEW SCIENTIST

X-ray boosting fabric could make mammograms less painful

A flexible fabric called X-Wear could replace some parts of medical scanners, which would make taking X-rays and CT scans far more comfortable and convenient

By Karmela Padavic-Callaghan

Mammograms can be painful, but they may not need to be

Daria Artemenko/Alamy

Getting an X-ray can be uncomfortable – you may have to lay still while you’re in pain or have part of your body compressed. But a flexible fabric that makes X-rays easier to detect could eliminate that.

“Imagine scanning a child’s injury without immobilising them, or enabling pain-free breast exams,” says Li Xu at the Hong Kong Polytechnic University. She and her colleagues created a textile called X-Wear that scintillates – meaning it releases light when exposed to X-rays – which could make this a reality.

Because X-rays are more difficult to detect than visible light, medical and industrial X-rays, as well as CT scans, use scintillating components. These can pick up X-rays after, for example, passing through a limb, converting the rays that emerge into visible light that can then be used to create an image of the body part to show internal detail like broken bones. But the most commonly used scintillators are rigid, which makes the devices they are embedded in bulky and uncomfortable to interact with.

To avoid this, the researchers re-shaped scintillating materials, for instance gadolinium oxide studded with bits of europium, into narrow fibres, which they then wove into fabric.

Xu says that it was a technical challenge to make these fibres flexible while also ensuring they emit enough light to create high-resolution images once they are hit with X-rays. Her team demonstrated that the fabric can be useful for taking dental X-rays – in tests, it made X-Wear conform to the shape of a mouth model made from clay and teeth. It also used it for mammography, where it created an X-Wear bra that eliminated the need for a person’s breast to be compressed during imaging, which is standard current practice.

Imalka Jayawardena at the University of Surrey in the UK says that X-Wear’s ability to conform to the body is a big advantage compared with other flexible scintillator designs that are typically film-like and bendy, but can’t wrap around objects. However, he says that detectors for light that X-Wear must be paired with are still flat, which currently limits possible uses of the fabric.

The researchers can produce samples of X-Wear up to around a quarter of a square metre, so before it can be widely used, they will have to scale its production to larger sizes and adapt it to industrial-grade equipment, says Xu.

The team is also working on industrial applications for X-Wear, such as small, flexible devices for inspecting electronics or pipelines for flaws. Xu says that first responders in a disaster zone could also use X-Wear alongside a smartphone and a compact X-ray source to do on-site scans.

Journal reference

Science Advances DOI: 10.1126/sciadv.adv5537

MATHEMATICS | JUN 27, 2025, 12:47 PM EDT | VIEW ON NEW SCIENTIST

Mathematicians create a tetrahedron that always lands on the same side

With the help of powerful computers, researchers discovered a four-sided shape that naturally rests on one side, and built a real-life version from carbon fibre and tungsten

By Alex Wilkins

The self-righting tetrahedron

Gergő Almádi et al.

A four-sided shape that will always come to rest on the same side no matter what side it starts on has been built by mathematicians, decades after it was first proposed to exist.

Mathematicians have long been fascinated by self-righting “monostable” shapes, which have a preferred resting spot when placed on a flat surface. One famous example is the Gömböc, a curved, tortoise-shell-shaped object that has a precise weight distribution and will rock side to side until it reaches the same stable resting place.

In 1966, mathematician John Conway was working on how straight-edged shapes balance and proved that a four-sided shape, or tetrahedron, with an even distribution of mass would be impossible. However, he told his colleagues at the time that an unevenly balanced monostable tetrahedron could be possible, but never proved it.

Now, Gábor Domokos at the Budapest University of Technology and Economics, Hungary, and his colleagues have built a monostable tetrahedron, which they call the Bille, using carbon-fibre struts and a plate made of ultra-dense tungsten carbide. The name comes from the Hungarian word for tip, billen.

They first started work on the problem when Domokos asked his student, Gergő Almádi, to search for Conway’s tetrahedron by conducting a brute-force search with powerful computers. “You check every tetrahedron, and with some luck, you find it, or with time, or with [computing power], or a mixture of those,” says Domokos.

As Conway predicted, they didn’t find any monostable tetrahedra with an even weight distribution, but they did find some candidate uneven ones, and went on to prove their existence mathematically.

Domokos and his team wanted to then build a real-life example, but this proved to be “an order of magnitude more difficult”, he says. This is because, according to their calculations, the difference between the density of the weighted and unweighted parts of the objects needed to be about 5000-fold, meaning the object would need to be essentially made from air but still rigid.

To make the shape, Domokos and his team partnered with an engineering company and spent thousands of euros to precisely engineer the carbon-fibre struts to within a tenth of a millimetre and make the tungsten base plate to within a tenth of a gram.

When Domokos first saw the functioning Bille in real life, he felt like he “was levitating 1 metre above the ground”, he says. “It is a big pleasure to know that you achieved something which would make John Conway happy.”

“There is no pattern, previous example or nothing in nature which would [have suggested to Conway] that this shape exists,” says Domokos. “It was in such an obscure corner of reality that no human [could] reach it” until now, “when you have powerful computers and you’re willing to pay thousands of dollars”.

The shape they constructed has a specific tipping path between its sides, says Domokos, tipping from B to A, from C to A, and from D to C and C to A. There is another kind of monostable tetrahedron that tips sequentially from D to C to B to A, but Domokos says their calculations indicate they would need a material that is one-and-a-half times as dense as the sun’s core to build it.

Domokos hopes their work will help engineers alter the geometry of lunar landers to make them less likely to fall over, as several recent spacecraft have done. “If you can do it with four faces, you can do it with any other number of faces.”

Reference:

arXiv DOI: arXiv:2506.19244

ENVIRONMENT | JUN 27, 2025, 12:30 PM EDT | VIEW ON NEW SCIENTIST

The bold plan to save a vital ocean current with giant parachutes

Large sea anchors could be used to drag water under a bold plan to keep the Atlantic Meridional Overturning Circulation moving – but some experts are sceptical

By Madeleine Cuff

The plan to maintain the ocean current would involve much larger versions of parachute sea anchors

Ed Dunens (CC BY 2.0)

Shipping tankers, drones and fishing boats could be used to drag giant parachutes through the waters of the Atlantic Ocean as part of a drastic plan to avert catastrophic climate change.

The Atlantic Meridional Overturning Circulation (AMOC) transports warm water from the tropics northwards, helping to keep northern Europe temperate.

However, a rapidly melting Arctic and warming ocean temperatures are weakening the current, with some scientists fearing it could shut down altogether at some point in the coming century. This would plunge oceanic ecosystems into chaos and rapidly cool Europe’s climate by several degrees.

Greenhouse gas emissions need to be cut rapidly to reduce the risk of AMOC collapse and other catastrophic climate “tipping points”, experts stress. But some are considering other, more radical approaches to keep the current going.

Stuart Haszeldine at the University of Edinburgh, UK, and David Sevier of UK water treatment firm Strengite presented one idea at the Arctic Repair conference in Cambridge, UK, this week. They say that just 35 sea tugboats could be used to pull underwater parachutes, each about the size of half a football pitch, to move enough water to maintain the current. “You can have that very large effect with a very small intervention of energy and equipment,” says Haszeldine.

The parachutes – similar in design to existing sea anchors, which are used to stabilise vessels in inclement weather – would help to propel the water flowing along the surface of the ocean. Each one would feature a hole with a 12-metre diameter in its centre to allow marine life to escape.

Drones, shipping tankers, tugboats or wind kites could be used to drag the parachutes, operating 365 days a year on a rotating-shift basis. “It’s a small but continuous intervention,” says Haszeldine.

Sevier described the idea as a “Hail Mary” to prevent the catastrophic consequences of an AMOC collapse. “This is about buying time,” he argues, for the world to cut emissions enough to stabilise global temperatures at a safe level.

However, the idea has been met with scepticism from leading AMOC researchers. René van Westen at Utrecht University in the Netherlands points out that differences in water density between cold, salty water and warm, fresher water are key to the downwelling and upwelling motion that sustains the AMOC.

“If [this idea is] possible, they can only maintain the surface layer using the overhead winds,” says van Westen. “The ocean density differences are far more important for the AMOC and hence, I’m not convinced that this can sustain the AMOC.”

Stefan Rahmstorf at the Potsdam Institute for Climate Impact Research in Germany agrees. “The issue is not to move surface water along horizontally; it is to make it sink down to a depth of 2000 to 3000 meters and flow back to the south as a cold deep current,” he says.

Meric Srokosz at the UK’s National Oceanography Centre says the proposal is “unlikely to work”, given the challenges of deploying equipment in the ocean in unpredictable weather conditions.

Haszeldine says he welcomes any feedback from other scientists on the idea and hopes ocean and climate modellers will help to investigate the ecological and environmental impacts of the plan. “We believe this to be worth investigating further,” he says.

More broadly, there should be more research focused on climate-intervention strategies to maintain ocean circulation, Haszeldine argues: “I don’t see anyone else working on ocean currents.”

EARTH | JUN 26, 2025, 3:00 PM EDT | VIEW ON NEW SCIENTIST

These rocks are probably the last remains of Earth's early crust

Geologists have long debated whether a stony formation in Canada contains the world’s oldest rocks – new measurements make a compelling case that it does

By James Dinneen

The Nuvvuagittuq Greenstone Belt in Canada may contain the world’s oldest rocks

Jonathan O’Neil

Just over 4 billion years ago, magma from Earth’s mantle infiltrated a fracture in the young planet’s primordial crust. Over the following aeons, nearly all of the planet’s early crust melted back into the mantle except for a small area around this fracture, which survives today.

At least, that is the story according to the latest analysis of radioactive isotopes in this rock, which is still accessible on the surface as part of the Nuvvuagittuq Greenstone Belt, a formation on the shore of Hudson Bay in Canada. This potential sample of Earth’s early crust is the subject of a long-standing debate among geologists: is it the world’s oldest rock, or merely extremely old?

Jonathan O’Neil at the University of Ottawa and his colleagues kicked off the debate in a 2008 study that estimated the rocks surrounding the intrusion are about 4.3 billion years old, which would make them the world’s oldest. With that age, they would have formed during the Hadean Aeon just a few hundred million years after the planet itself.

While a few mineral grains have been found that are older than that, complete Hadean rocks would offer a new window on this early period of Earth’s history, perhaps shedding light on geological mysteries like the start of plate tectonics and the make-up of the first oceans.

However, the method the researchers used to date the rocks made the 4.3-billion-year-old age controversial. Ideally, very old rocks can be dated using a hardy mineral called zircon, which maintains its original chemical make-up over billions of years. But these volcanic rocks didn’t contain zircon. “We can’t date these rocks using that technique that everybody loves,” says O’Neil.

Instead, they measured the atomic weight of neodymium and samarium in the rock. As samarium decays, it produces different isotopes of neodymium at known rates. The ratio of neodymium and samarium isotopes remaining in the rocks can thus serve as a “clock” counting up from the time the rock crystallised from magma. In fact, two isotopes of samarium decay at different rates, allowing them to serve as two parallel clocks. The trouble was, the two clocks didn’t agree on the age of the rock, leading researchers to dispute that it actually was Hadean.

“I don’t think a majority of the early-Earth-studying community was convinced,” says Richard Walker at the University of Maryland.

Now, O’Neil and his colleagues have counted neodymium and samarium isotopes in rocks that intrude into the layer they think is 4.3 billion years old. By definition, such intrusions are younger than the strata that surround them. Therefore, dating the intrusion would set a minimum age for the surrounding rock.

A detailed view of the Nuvvuagittuq Greenstone Belt in Canada

David Hutt / Alamy

In the intrusion, unlike the older rock that surrounds it, the two clocks tell the same story: the rock is about 4.16 billion years old. “Both clocks are giving the exact same age,” says O’Neil. This supports the idea that the surrounding rock formed well within the Hadean Aeon, which would make it the only known remnant of Earth’s early crust.

“I think they make as good a case as you can make,” says Graham Pearson at the University of Alberta in Canada.

“The simplest explanation for this data is that these are the oldest rocks in the world,” says Jesse Reimink at the Pennsylvania State University. However, this is unlikely to be the last word on the matter, he says. “When dealing with the oldest rocks and minerals, there’s no such thing as settled.”

Journal reference:

Science DOI: 10.1126/science.ads8461

SPACE | JUN 26, 2025, 6:09 PM EDT | VIEW ON NEW SCIENTIST

Mystery fireball spotted plummeting to Earth over the US

There have been hundreds of reports of sightings of a “fireball” in the skies over the southern US – it may have been a meteor breaking up as it falls through Earth’s atmosphere

By Jeremy Hsu

A fireball captured on a dashcam in South Carolina

Kathryn Rose Farr via Facebook

Sightings of a fireball streaking down from the sky were reported by eyewitnesses in several south-eastern US states on the afternoon of 26 June.

The American Meteor Society’s website has logged at least 142 reports about the fireball event from observers in multiple states such as Alabama, Florida, Georgia, North Carolina, South Carolina and Tennessee. The National Weather Service office in Charleston, South Carolina, said that “satellite-based lightning detection” showed a streak in the sky over the border between North Carolina and Virginia between 11.51 and 11.56am Eastern Daylight Time.

A dashcam video from a driver in upstate South Carolina shows the fiery object plummeting from the sky before disappearing behind a forested area adjacent to the highway. Another car driving south-west of Columbia, South Carolina, also captured footage of the falling object.

“This was clearly a natural rock coming down and not artificial space debris,” says Jonathan McDowell, an astronomer who tracks space launches.

VIDEO | This was just sent to me taken from a dash camera on I-85 SB in Upstate South Carolina pic.twitter.com/49PvNsorAK

— Cody Alcorn (@CodyAlcorn) June 26, 2025

It may have been what’s known as a bolide fireball event, where a bright meteor explodes and breaks apart as it falls through Earth’s atmosphere, said Mike Hankey at the American Meteor Society in an interview with WXIA-TV in Georgia.

Meteorologist Chris Jackson posted on social media that local fire departments were responding to reports of “fireballs falling out of the sky” but added that the emergency responders had not found anything on the ground as of early afternoon.

There are currently no major meteor showers active and visible from Earth. The next major meteor shower event involves the Southern delta Aquariids starting next month.

LIFE | JUN 26, 2025, 3:00 PM EDT | VIEW ON NEW SCIENTIST

Ash trees are rapidly evolving some resistance to ash dieback disease

DNA sequencing shows young trees are more likely to have gene variants that confer partial resistance to a fungus that has been wiping out ash trees across Europe

By Michael Le Page

Some ash trees have genetic variants that confer partial resistance to ash dieback

FLPA / Alamy

Ash trees in the UK are rapidly evolving resistance in response to ash dieback disease, DNA sequencing of hundreds of trees has shown.

The finding is good news, says Richard Buggs at the Royal Botanic Gardens, Kew, in the UK, but it is unlikely that ash trees will become completely resistant in the near future. “We probably need a breeding programme so that we can help nature along and finish the job,” he says.

Ash dieback is caused by a fungus (Hymenoscyphus fraxineus) native to Asia that slowly destroys trees’ ability to transport water. It began spreading in Europe in the 1990s and reached the UK in 2012.

Link to video: https://www.youtube.com/watch?v=i7pJIFNUFNw

The death of ash trees leads to the release of carbon dioxide and affects hundreds of species that rely on these trees for their habitat. Falling trees are also a threat to people and property. “There’s a lot of ash close to footpaths and roads that is now quite dangerous,” says Buggs.

Because the fungus takes much longer to kill large trees than young ones, Buggs’s team was able to compare the genomes of 128 adult European ash trees (Fraxinus excelsior) and 458 saplings at a site called Marden Park in Surrey. This revealed that thousands of variants his team had previously shown to be linked to resistance were more common in the young trees – probably because those that lacked them had died off.

It is the most detailed genetic picture of evolution in action ever obtained in the wild. “What’s original about this study is we’ve been able to characterise the genetic basis and then demonstrate a shift happening in a single generation,” says Buggs.

However, each of the gene variants has only a tiny effect, rather than conferring complete resistance. The rate of evolutionary change will also slow in the future as large ash trees die off and fewer fungal spores are produced, meaning young ash trees will have a better chance of surviving, says Buggs.

“It’s a massive problem, but they’re not going to disappear,” he says. “I think our results encourage us that some of these young ash trees will hopefully make it through to adulthood, and hopefully have another generation of natural selection.”

Ash dieback hasn’t yet spread to North America, but an introduced insect pest, the emerald ash borer (Agrilus planipennis), is spreading and killing ash trees there. It isn’t clear what will happen if ash dieback and the emerald ash borer both arrive in the same region, but it could make the situation much worse.

“Globalisation is mixing up the world’s insects and microbes, and so we are increasingly seeing these new tree epidemics, and it is very hard for the trees to keep up with it,” says Buggs. “Trees are facing threats that they’ve never faced before, coming at them at speeds that they never have before.”

He thinks we need to step in to help trees survive the onslaught, for instance by crossing native trees with exotic species to create resistant hybrids.

“One of the answers is to be moving the genetic diversity of trees around the world as well, to keep up with all of the pests and pathogens that we’re moving around,” he says.

Journal reference:

Science DOI: 10.1126/science.adp2990

MIND | JUN 26, 2025, 3:00 PM EDT | VIEW ON NEW SCIENTIST

Deep sleep seems to lead to more eureka moments

After a nap, people who entered the second stage of sleep were more likely to spot a solution to a problem than those who slept lightly or not at all

By Christa Lesté-Lasserre

Taking a nap might help with solving problems

Pavel Marys / Alamy

Waking up from a deep nap appears to make people better at creative problem-solving.

In a new study, people were more likely to have a “eureka” moment if they had recently entered the second stage of sleep than if they slept lightly or not at all.

The findings suggest that a brief, deep nap can trigger valuable moments of insight, says Anika Löwe at the Max Planck Institute for Human Development in Berlin.

“I think we’re at the very beginning of uncovering what’s actually happening during sleep that makes it so beneficial,” she says. “One possibility is that during deep sleep, our brains sift through what’s relevant and what’s irrelevant, and so when we wake up we have these insight moments that get to the gist of the problem.”

Previous studies have mostly found that naps can boost creativity and help people solve problems, but there is disagreement over which stage of sleep is most beneficial. Several suggest that the lightest stage of non-REM sleep, N1, is ideal – an idea embraced by Thomas Edison, who reportedly used to nap holding steel balls that would crash loudly to the floor and wake him up if he drifted too deeply into sleep. But other studies suggest that the deeper N2 stage – still lighter than slow-wave sleep, N3 – triggers more innovation.

To investigate further, Löwe and her colleagues asked 90 people who were aged 18 to 35 and didn’t have a sleep disorder to use a keyboard to classify the direction of motion of hundreds of rapidly flashing dot patterns on a screen. The researchers didn’t inform the participants that the dots’ colours gradually began to predict the correct answer partway through the task.

Fifteen participants spontaneously figured out the shortcut during the first 25 minutes of the task. The remaining 75 were invited to lie down for a 20-minute nap in a quiet, dark room, while hooked up to EEG monitors that tracked their brain activity.

After the nap, they tried the tasks again. This time, most of the participants figured out the shortcut from the colours, but the likelihood of a eureka moment appeared to depend on how deeply the people had napped. Among the 68 participants whose EEG data permitted high-quality readings, 85.7 per cent of people who fell into deep N2 sleep figured out the shortcut, compared with only 63.6 per cent of those who only reached the lighter N1 phase and only 55.5 per cent of those who didn’t slip into sleep at all.

The study clearly shows that deeper sleep facilitates eureka moments – at least for this particular task, says Itamar Lerner at the University of Texas at San Antonio. “The type of task used is critical for whether it is boosted by sleep or not.”

Delphine Oudiette at the Paris Brain Institute notes that different task designs could explain why her team found significantly more problem-solving after N1 sleep. “Maybe both sleep stages matter, but for different types of cognitive processes that we have to isolate to understand better,” she says.

Björn Rasch at the University of Fribourg, Switzerland, says the findings clearly support the idea that deeper sleep may support problem-solving. Even so, he cautions that the study’s design makes it hard to separate cause from coincidence. Because participants weren’t randomly assigned to sleep stages or studied individually across different sleep scenarios, it is possible that those who managed to fall asleep in an IKEA armchair at a research lab might just happen to be those who “simply have higher insight capabilities”, especially after a nap, he says.

Journal reference:

PLOS Biology DOI: 10.1371/journal.pbio.3003185

ENVIRONMENT | JUN 26, 2025, 11:17 AM EDT | VIEW ON NEW SCIENTIST

Nearly a third of Tuvaluans have applied for climate migration visa

With their country threatened by sea level rise, the people of Tuvalu have been offered an escape route through an agreement with Australia, and many are contemplating leaving their home

By James Woodford

Tuvalu is extremely vulnerable to sea level rise

Photo by Mario Tama/Getty Images

How does it feel to lose your home to climate change? The roughly 10,000 residents of Tuvalu will be among the first in the world to have to confront this question.

With an average height above sea level of less than 3 metres, Tuvalu is on course to become completely uninhabitable due to flooding, storm surges and erosion. By 2100, sea levels are projected to rise by 72 centimetres and the coral atoll archipelago, which is roughly midway between Australia and Hawaii, is expected to experience flooding for nearly a third of every year.

But the people of Tuvalu have been offered an escape route. In late 2023, the Australian government announced that it would launch what effectively amounts to the world’s first planned migration of an entire nation.

Under the Australia-Tuvalu Falepili Union Treaty, 280 Tuvaluans each year will be granted Australian residency through a ballot. The first lottery opened on 16 June this year, and 3125 citizens – nearly a third of the country’s population – have already applied. The closing date to register for this year’s lottery is 18 July.

In a statement to New Scientist, the Australian government said it recognises the “devastating impact climate change is having on the livelihoods, security and well-being of climate-vulnerable countries and people, particularly in the Pacific region”.

“This is the first agreement of its kind anywhere in the world, providing a pathway for mobility with dignity as climate impacts worsen,” the government said.

Successful applicants should know the results of the lottery by the end of July and the first migrants are expected to arrive in Australia by the end of the year.

Bateteba Aselu is a Tuvaluan doctoral student at the University of Melbourne, Australia, researching the challenges posed by climate change to her compatriots. Aselu is currently on a student visa in Australia while completing her studies, but is considering lodging an application to join this year’s ballot along with her husband. Her son, who has just graduated from high school, has already applied.

She says the impacts of climate change are already being felt because the freshwater aquifers that underlie Tuvalu’s atolls, which are critical for agriculture and drinking water, are being infiltrated by seawater due to sea level rise. This is forcing people to raise their crops off the ground to keep the salinity at bay.

Stephen Howes at the Australian National University in Canberra says the new visa is “remarkably liberal”, giving successful applicants full access to nearly all Australian health and social security benefits, without discrimination based on chronic health conditions, disabilities, age or other exclusions, which is common in other visa streams.

While the agreement is ostensibly about helping Tuvalu deal with its imminent climate crisis, the prize for Australia is to stymie China’s push for power in the Pacific, says Howes. The treaty has a provision that Australia and Tuvalu must “mutually agree on” matters of security and defence agreements between the island state and other countries.

“I’ve described it as a security-migration agreement,” says Howes. “Climate change provides the framing, but it is an arrangement whereby Tuvalu gives Australia privileged security treatment, in return for which Australia will give Tuvalu privileged migration treatment.”

Tuvaluan people taking part in traditional fishing practice

MICK TSIKAS/EPA-EFE/Shutterstock

Jane McAdam at the University of New South Wales in Sydney says there are diverse views in Tuvalu about what the future holds. People have said to her that they were told the island would be underwater by now and it isn’t. She also says there are older people who say they will never leave and will die on the islands.

But McAdam sees the new migration scheme as “decent and positive”. One important aspect is that once a Tuvaluan has gained the visa, they can return home as often as they like or even live there until the situation on the atolls becomes too dire.

It will be “like an oxygen mask on an airplane”, says McAdam. “Hopefully, you will never need it, but you’re very grateful it’s there.”

Wesley Morgan, who is also at the University of New South Wales, says until now, Tuvaluans have had limited escape options if conditions deteriorated. The agreement could be extended to other nations in similar circumstances, such as Kiribati.

“This is potentially a precedent, a global first where a migration pathway is explicitly tied to climate change and sea level rise,” says Morgan. “And because of these unique circumstances, I think Australia might pursue similar arrangements in future with Kiribati.”

The question that remains for the Tuvaluan people is how they resolve their identity and sovereignty after moving away from their islands. Will they be a Tuvaluan diaspora or a nation in climate exile?

“If you have a place where you grew up and something happened and you had to move, how would you feel?” says Aselu. “Would you feel lost? Yes. So, I think that is the kind of feeling that you will have in any place around the world where you lose the place that you love, that you belong to and you feel identified with.

“Because you grew up in that place. It’s where your history is. It’s where your families are from, and it’s a place you identify with regardless of where you are in the world. And if that place is lost, how do you identify yourself? How do we identify ourselves?”

ENVIRONMENT | JUN 26, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

Extreme winter weather isn’t down to a wavier jet stream

The recent erratic behaviour of the polar jet stream isn't out of the ordinary, researchers have found by compiling data from the past 125 years

By Madeleine Cuff

A wavy polar jet stream can bring icy storms further south

Science History Images / Alamy Stock Photo

Increasingly erratic winter weather in the northern hemisphere isn’t a result of the polar jet stream getting more wavy, according to new research – although climate change is making winter storms more intense in other ways.

The northern polar jet stream is a current of winds that sweeps through the northern hemisphere, steered by the boundaries between temperate air and cold air around the Arctic.

For more than a decade, some researchers have suspected that a warming Arctic is causing the jet stream to buckle more dramatically in the winter, causing extreme storms that bring snow and ice much further south than usual.

But the theory has been hard to verify, in part due to the relatively short satellite data record, and also because of the jet stream’s intense natural variability during the winter months.

Erich Osterberg at Dartmouth College, New Hampshire, and his colleagues set out to identify whether the recent behaviour of the jet stream is out of the ordinary compared with the long-term average.

Satellites only began collecting jet stream data in 1979, so the researchers used data on temperature and atmospheric pressure stretching back to 1901 to reconstruct the movement of the polar jet over the US for the rest of the 20th century.

They found the polar jet has experienced several periods of increased waviness during that time, suggesting the recent erratic behaviour isn’t out of the ordinary. In some instances, the winter jet stream was even wavier in the past than it is today. “What is happening now with the jet stream does not actually look all that unusual when you zoom out and look at the entire 20th century,” says Osterberg.

Winters in the northern hemisphere are becoming warmer and wetter as a result of climate change driving more intense storms and rainfall, even without the jet stream changing, stresses Osterberg. “It is clear climate change is affecting extreme weather events in all sorts of really important ways,” he says. “What we’re saying is that when it comes to the wintertime jet stream, it does not appear like the jet stream is a critical component of these changes.”

Tim Woollings at the University of Oxford says the research is a reminder of how important it is to assess long-term data when identifying changes to the polar jet stream, the behaviour of which can vary hugely over the short and medium term.  “By using several long data records and a range of methods, it shows how the jet waviness in recent North American winters is no worse than in earlier decades,” he says.

It is a different story during the northern hemisphere summer, however, with mounting evidence suggesting that the polar jet is becoming wavier in the warmer months as a result of climate change driving up air temperatures in the tropics. “In the summertime, it does appear that the jet stream is seeing a fundamental change in behaviour, where it is getting slower, with bigger waves, which leads to things like big heatwaves, drought and wildfires,” says Osterberg. “That does appear to be associated with climate change.”

Journal reference:

AGU Advances DOI: 10.1029/2024AV001399

SOCIETY | JUN 25, 2025, 4:07 PM EDT | VIEW ON NEW SCIENTIST

Independent estimate of Gaza deaths is higher than official figures

A study based on household surveys suggests that from October 2023 to January 2025, around 75,000 people in Gaza died violent deaths, while Gaza's health ministry estimates 46,000 for the same period

By Michael Le Page

Destroyed buildings in Jabalia, Gaza, in February 2025

Imago/Alamy

Around 75,000 people in the Gaza Strip – 3.6 per cent of the population – died from violent causes between 7 October 2023 and 5 January 2025, according to an independent study based on a household survey. That is higher than the estimate of 46,000 violent deaths during this period by Gaza’s health ministry.

The study also estimates that there were nearly 9000 more non-violent deaths during this period than would normally be expected in the Gaza Strip. This is the first ever estimate of the indirect deaths due to the war in the region that began in October 2023.

The study is based on interviews with 2000 randomly selected households, with people asked to list all members of the household before the war and then the current situation. “We actually were in the field, and we collected data straight from the population,” says Debarati Guha-Sapir at the Catholic University of Louvain in Belgium.

While the team was unable to access some areas due to ongoing fighting and Israeli evacuation orders, this gap would likely lead to underestimation rather than overestimation, the researchers think.

Guha-Sapir says Gaza’s health ministry has stringent criteria for counting deaths. For instance, it does not count deaths where no bodies have been found, such as people who have been buried in tunnels. So she thinks her team’s estimate is closer to the true number.

Another independent study published in February concluded that the death toll up to 24 June 2024 was higher than the official numbers by a similar proportion. However, the sources used in that study included an online survey and social media obituaries, so Guha-Sapir thinks her team’s approach is more reliable.

Francesco Checchi at the London School of Hygiene & Tropical Medicine, whose team carried out the February study, disagrees. “The survey isn’t necessarily more accurate than our study,” he says. But Guha-Sapir’s study is more up to date, and also includes indirect deaths, says Checchi. “As such, it presents a more complete picture of mortality.”

The estimate of around 9000 indirect deaths as a result of the war is lower than some previous suggestions. In fact, in a letter in The Lancet in 2024, three researchers claimed on the basis of what has happened in other conflicts that there might be four indirect deaths for every direct death in Gaza, and thus that the death toll at that time could be as high as 186,000.

But that ratio of indirect deaths to direct ones has been seen only in countries such as Sudan where there was extreme poverty and poor healthcare before conflicts began, says Guha-Sapir. It’s a mistake to apply it to Gaza, where the situation was different than that of Sudan before the war began, she says.

However, if the conflict continues, this could yet change. “As conditions deteriorate, nonviolent deaths may soon rise rapidly,” says team member Michael Spagat at Royal Holloway University of London.

Reference:

medRxiv DOI: 10.1101/2025.06.19.25329797

HUMANS | JUN 25, 2025, 3:00 PM EDT | VIEW ON NEW SCIENTIST

Ancient mammoth-tusk boomerang is twice as old as we thought

A boomerang discovered in a Polish cave was originally dated as 18,000 years old, but it may have been contaminated by preservation materials. A new estimate suggests the mammoth-ivory artefact is 40,000 years old

By Christa Lesté-Lasserre

An artefact made from a mammoth tusk is the oldest known boomerang

Talamo et al., 2025, PLOS One, CC-BY 4.0

The world’s oldest known boomerang may be 22,000 years older than previously thought, suggesting it was crafted during a period when early humans displayed an increase in artistry.

In 1985, archaeologists unearthed a 72-centimetre-long ivory boomerang buried beneath six layers of sediment in Obłazowa cave in Poland. Later sediment sieving revealed a Homo sapiens thumb bone nearby, as well as antler tools, a bone bead and pendants made from fox teeth. In the 1990s, radiocarbon dating suggested the thumb was 31,000 years old – but surprisingly, the boomerang was dated to just 18,000 years old, several millennia younger than the artefacts in higher layers.

Sahra Talamo at the University of Bologna in Italy suspected contamination. “Even a trace amount of modern carbon – from glue or conservation products – can throw off the radiocarbon date by tens of thousands of years,” she says. Analyses of the thumb’s carbon-nitrogen ratios showed signs that the collagen might have been contaminated, so the researchers treated the radiocarbon date as a minimum age.

Re-dating the contaminated boomerang would have been futile – and would have damaged the precious artefact needlessly, says Talamo. Instead, she and her colleagues dated 13 nearby animal bones, re-dated the human thumb bone and used statistical modelling to reconstruct the timeline. Their results showed that the entire sediment layer – and hence the boomerang and thumb as well – dates to between 39,000 and 42,000 years ago.

“In a way, this is an advertisement to museums that when you find something extraordinary, you should not cover it with glue or other restoration materials before completing all your analyses,” she says.

Its new age means the ivory boomerang predates the second-oldest known boomerangs – made from wood by Indigenous Australians – by 30,000 years. Unlike simpler throwing sticks, such as a 300,000-year-old wooden implement found in Schöningen, Germany, boomerangs are curved and aerodynamically shaped, even if they don’t always return to the thrower, says Talamo.

Indeed, although the ancient boomerang could most likely fly, its size and design probably made it unlikely to return to sender. Instead, it may have served a symbolic or ceremonial purpose, says Talamo, based on its decorative engravings, reddish pigment and smooth polish – combined with its placement beside a human thumb bone in a circle of imported stones.

The finding offers a glimpse into early humans’ cognitive abilities and craftsmanship during a burst of artistic expression that occurred during the Early Aurignacian period, starting around 40,000 years ago. During this time, symbolic artefacts such as mammoth ivory figurines, rock art and aesthetically crafted tools first appeared in Europe, says Talamo.

Journal reference

PLOS One DOI: 10.1371/journal.pone.0324911

Article amended on 26 June 2025

We clarified the implications of the thumb’s carbon-nitrogen ratios

HEALTH | JUN 25, 2025, 3:00 PM EDT | VIEW ON NEW SCIENTIST

Gastric bypass surgery may cut the risk of bowel cancer

Weight-loss surgery seems to lower the risk of colorectal cancer by changing where bile acids enter the small intestine, raising the possibility of developing treatments that mimic these effects

By Carissa Wong

Gastric bypass surgery is generally used for weight loss, but it may have other benefits

Portra/Getty Images

A common form of weight-loss surgery may cut the risk of colorectal cancer by altering levels of molecules called bile acids in the blood and small intestine. The findings could lead to new treatments for bowel cancer.

Gastric bypass surgery involves stapling the stomach to form a small upper pouch and a larger lower pouch. The small intestine is then connected to the upper pouch so food and digestive juices bypass most of the stomach and the start of the small intestine. After having the surgery, people typically feel full sooner and lose weight.

Prior studies have also linked the procedure to a reduced risk of colorectal cancer, but it was unclear why. To find out, Rebecca Kesselring at the University of Freiburg in Germany and her colleagues fed mice a high-fat diet until they gained around 50 per cent of their initial body weight, on average. They then gave a third of the mice gastric bypass surgery while the rest underwent sham surgery that didn’t rearrange their digestive organs.

Aiming to isolate the effect of having gastric bypass surgery from that of losing weight, the team put the gastric bypass group and half of the remaining mice on a diet that caused them to lose about a fifth of their weight, on average, over six weeks.

The researchers then implanted colorectal cancer cells into the mice’s colons. After another six weeks, they found that colon tumours in the gastric bypass group were two-thirds smaller than those of either the mice that had kept gaining weight or the mice that had lost weight through diet alone.

What’s more, tumours had spread to the liver in only one mouse out of 20 in the gastric bypass group, while this occurred in most animals in the sham groups.

“As both sham groups had similar tumour levels but different weights, weight loss itself didn’t account for the reduced cancer risk – there was something else about bypass surgery,” says Kesselring.

The team wondered if changes in bile acids, a mix of molecules that digest fats, might be responsible. These are usually made by the liver and pass through the gall bladder, stomach and small intestine before returning to the liver via the blood.

“With bypass surgery, bile acids are introduced later into the small intestine,” says Kesselring. This means they may encounter a different mix of gut bacteria, which chemically alter the molecules.

The mice that underwent gastric bypass surgery had reduced levels of some bile acids called primary bile acids in their colons and blood compared with those in the sham groups.

To test whether bile acid changes really did alter cancer risk, the team put another group of mice through the same experiment – but instead of gastric bypass surgery, these mice had an operation that simply diverted their bile acids to a later part of their small intestine without altering the stomach.

Crucially, the team found that this lowered levels of primary bile acids in the blood and reduced the size and spread of colorectal tumours in these mice as effectively as gastric bypass surgery. This was supported by another experiment where the team found that primary bile acids boost the growth of colorectal cancer cells in a lab dish.

The findings suggest that targeting primary bile acids could help treat cancer. “We could maybe figure out some oral drug that reduces these bile acids, that we could give to people with cancer, to simulate some of these beneficial effects of [gastric bypass] surgery,” says Vance Albaugh at Louisiana State University.

Journal reference:

Science Translational Medicine DOI: 10.1126/scitranslmed.ads9705

HEALTH | JUN 25, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

Cancer cells steal mitochondria from nerve cells to fuel their spread

Cancer cells can acquire energy-generating structures called mitochondria from nearby nerve cells, which seems to aid their spread, a discovery that could lead to new treatments

By Carissa Wong

A nerve cell (stained green) growing among a cancer cell culture

Simon Grelet and Gustavo Ayala

Cancer cells steal energy-generating parts from nerve cells to fuel their spread to distant sites, a discovery that could improve treatments against the deadliest tumours.

“This is the first time that mitochondrial exchange has been demonstrated from nerves to cancer cells,” says Elizabeth Repasky at the Roswell Park Comprehensive Cancer Center in Buffalo, New York, who wasn’t involved in the research. “It’s a major next step in cancer neuroscience, a field that’s exploding.”

We already knew that nerve cells, or neurons, within and surrounding tumours produce proteins and electrical signals that help cancer grow and spread. “Cancers with higher nerve density are associated with poorer prognosis,” says Simon Grelet at the University of South Alabama.

Prior studies have also shown that brain cancer cells can acquire mitochondria – energy-generating structures – from non-neuronal brain cells. But it was unknown whether tumour cells could take mitochondria from nerve cells, says Grelet.

To find out, he and his colleagues genetically engineered breast cancer cells from mice to contain a red fluorescent molecule and mixed them with mouse nerve cells, containing mitochondria labelled with green pigment, in a lab dish. By imaging the cells, they found that cancer cells stole mitochondria from the nerve cells within a few hours.

“The cancer cells elongate their membrane so they are stealing, siphoning, the mitochondria from the neurons,” says Grelet. “It’s like a train of mitochondria that pass through a very tiny structure, entering the cancer cell one at a time,” he says.

To see if this occurs in the body, the researchers injected red breast cancer cells into the nipples of female mice to form tumours. They also genetically engineered the nerves around the tumours to carry green mitochondria. Around a month later, 2 per cent of the cancer cells in these tumours had acquired mitochondria from neurons.

In contrast, 14 per cent of tumour cells that had spread to the brain carried nerve-derived mitochondria – suggesting that cancer cells with nerve-derived mitochondria were much better at spreading than those without. Further experiments suggest this is because cells with stolen mitochondria are better at enduring physical and chemical stresses that they encounter in the bloodstream.

“There are many, many obstacles for a cancer cell that’s trying to spread,” says Repasky. “They have to break out of the initial tumour, make it through barriers of the blood vessels, get out of the blood, then get enough oxygen and nutrients at the secondary site – most of them don’t make it,” she says. “Stealing mitochondria seems to allow cancer cells to better endure that obstacle course,” she says.

To explore if this happens in people, the researchers analysed tumour samples from eight women with breast cancer that had spread to distant sites within their bodies. They found that tumour cells from other parts of the body had 17 per cent more mitochondria, on average, compared with those in the breast, suggesting the process does occur in patients, says Grelet.

What’s more, the team analysed a human prostate tumour sample and found that cancer cells closer to nerves contained substantially more mitochondria than those further away. “We think it would be a universal mechanism that all sorts of tumours will be doing,” says team member Gustavo Ayala at the University of Texas Health Sciences Center at Houston.

The findings suggest that blocking mitochondrial transfer could reduce the spread of the deadliest tumours. “I do believe this will be possible, at least in certain kinds of tumours,” says Repasky. Ayala says the researchers plan to develop drugs that can do this.

Journal reference:

Nature DOI: 10.1038/s41586-025-09176-8

HEALTH | JUN 25, 2025, 6:00 AM EDT | VIEW ON NEW SCIENTIST

Heart attacks are no longer the leading cause of death in the US

Since 1970, heart attack deaths have fallen almost 90 per cent in the US, though deaths from chronic heart conditions have significantly risen

By Grace Wade

Bystander CPR training may have contributed to fewer heart attack deaths in the past five decades

piyamas dulmunsumphun / Alamy Stock Photo

Deaths from heart attacks have plummeted in the US over the past 50 years, whereas deaths from chronic heart conditions have skyrocketed, probably due to people living longer.

“We’ve made some really great progress in certain areas of heart disease mortality, but now we’re seeing this shift,” says Sara King at Stanford University in California.

She and her colleagues collected data on heart disease deaths from 1970 to 2022 using the US Centers for Disease Control and Prevention’s WONDER database, which tracks all recorded fatalities in the country.

They found that in 2022, heart disease accounted for 24 per cent of all deaths in the US, down from 41 per cent in 1970. The decline is largely thanks to an almost 90 per cent decrease in heart attack deaths, which were once the deadliest form of heart disease.

“Incredible progress has been made to reduce deaths from heart attacks over the last 50 years,” says King. This includes new therapies such as heart stents, coronary artery bypass surgery and cholesterol-lowering medications. Public health measures, such as bystander CPR training and efforts to lower smoking rates, have also probably helped, says King.

Even so, heart disease remains the country’s top killer, mainly because deaths from other types of heart disease – mostly chronic conditions – have increased 81 per cent over the same period. For instance, fatalities from heart failure, arrhythmia and hypertensive heart disease have risen 146 per cent, 106 per cent and 450 per cent, respectively.

“A lot of these conditions are conditions that come with age,” says King. “To us, it seems like people that are now surviving these heart attacks are living longer and having more time to sort of develop these chronic heart conditions.”

However, the data may exaggerate the shift in heart disease deaths. “There are a lot of different causes that could lead to somebody’s death, and that can lead to misclassification or oversimplification,” says King. For instance, many people die from heart failure after having survived a heart attack. “The underlying cause of that heart failure is still the blockages in those coronary arteries, so it isn’t black and white,” says King.

Still, the majority of heart disease deaths are clearly no longer due to heart attacks. “It is going to be important that we focus on these other rising causes of mortality,” says King. “Finding ways to age healthily will be the next frontier in cardiology.”

Journal reference:

Journal of the American Heart Association DOI: 10.1161/JAHA.124.038644

TECHNOLOGY | JUN 25, 2025, 7:48 AM EDT | VIEW ON NEW SCIENTIST

Generation Alpha's coded language makes online bullying hard to detect

Adults and AI models fail to recognise messages with harmful intent expressed with Gen Alpha slang or memes, raising concerns about youngsters’ online safety

By Chris Stokel-Walker

Teenagers’ language might make online bullying hard to detect

Vitapix/Getty Images

Generation Alpha’s internet lingo is mutating faster than teachers, parents and AI models can keep up – potentially exposing youngsters to bullying and grooming that trusted adults and AI-based safety systems simply can’t see.

Manisha Mehta, a 14-year-old student at Warren E. Hyde Middle School in Cupertino, California, and Fausto Giunchiglia at the University of Trento, Italy, collated 100 expressions and phrases popular with Generation Alpha – those born between 2010 and 2025 – from popular gaming, social media and video platforms.

The pair then asked 24 volunteers aged between 11 and 14, who were Mehta’s classmates, to analyse the phrases alongside context-specific screenshots. The volunteers explained whether they understood the phrases, in what context they were being used and if that use carried any potential safety concerns or harmful interpretations. They also asked parents, professional moderators and four AI models – GPT-4, Claude, Gemini and Llama 3 – to do the same.

“I’ve always been kind of fascinated by Gen Alpha language, because it’s just so unique, the way things become relevant and lose relevancy so fast, and it’s so rapid,” says Mehta.

Among the Generation Alpha volunteers, 98 per cent understood the basic meaning of the terms, 96 per cent understood the context in which they were used and 92 per cent could detect when they were being deployed to cause harm. But the AI models only recognised harmful use in around 4 in 10 cases – ranging from 32.5 per cent for Llama 3 to 42.3 per cent by Claude. Parents and professional moderators were no better, spotting only around a third of harmful uses.

“I expected a bit more comprehension than we found,” says Mehta. “It was mostly just guesswork on the parents’ side.”

The phrases commonly used by Generation Alpha included some that have double meanings depending on their context. “Let him cook” can be genuine praise in a gaming stream – or a mocking sneer implying someone is talking nonsense. “Kys”, once shorthand for “know yourself”, now reads as “kill yourself” to some. Another phrase that might mask abusive intent is “is it acoustic”, used to ask mockingly if someone is autistic.

“Gen Alpha is very vulnerable online,” says Mehta. “I think it’s really critical that LLMs can at least understand what’s being said, because AI is going to be more prevalent in the field of content moderation, more and more so in the future.”

“It’s very clear that LLMs are changing the world,” says Giunchiglia. “This is really paradigmatic. I think there are fundamental questions that need to be asked.”

The findings were presented this week at the Association for Computing Machinery Conference on Fairness, Accountability and Transparency in Athens, Greece.

“Empirically, this work indicates what are likely to be big deficiencies in content moderation systems for analysing and protecting younger people in particular,” says Michael Veale at University College London. “Companies and regulators will likely need to pay close attention and react to this to remain above the law in the growing number of jurisdictions with platform laws aimed at protecting younger people.”

Reference:

FAccT ’25: Proceedings of the 2025 ACM Conference on Fairness, Accountability, and Transparency DOI: 10.1145/3715275.3732184

LIFE | JUN 24, 2025, 8:01 PM EDT | VIEW ON NEW SCIENTIST

Small and speedy dinosaur recognised as a new species

Enigmacursor darted around North America in the Late Jurassic 145-150 million years ago and its skeleton now be on display in London’s Natural History Museum

By Chris Simms

Illustration of Enigmacursor mollyborthwickae, a newly recognised dinosaur species

© The Trustees of the Natural History Museum, London

A newly discovered species of dinosaur is going on display in London’s Natural History Museum.

Enigmacursor mollyborthwickae was a speedy, two-legged herbivore, 64 centimetres tall and 180 cm long that lived about 145 million to 150 million years ago, during the Late Jurassic Period.

Its reconstructed skeleton will be on display in the museum’s Earth Hall from 26 June, alongside its contemporary, Sophie the Stegosaurus.

Susannah Maidment and Paul Barrett, both palaeontologists at the Natural History Museum, have analysed the Enigmacursor specimen, which was uncovered from the Morrison Formation in the western US in 2021-22.

Back then, it was thought to be a Nanosaurus – a poorly known species of small herbivorous dinosaur. The Enigmacursor fossil isn’t complete, but using the few teeth – which reveal it ate plants – and portions of the neck, backbone, tail, pelvis, limbs and feet, Maidment and Barrett have defined this fossil as a new species, placed it in an evolutionary tree and reconstructed it for display.

Link to video: https://www.youtube.com/watch?v=YKdD5GgUp8o

They have based the structure of missing elements, like the skull, on similar small dinosaurs like Yandusaurus and Hexinlusaurus. Generally, we know little about smaller dinosaurs, both because they are less likely to fossilise than bigger animals and because fossil hunters tend to seek larger, more valuable examples.

“This is a two-legged dinosaur and it’s got very small forearms that it probably would have used to grasp food to bring it to its mouth,” says Maidment. “And it’s got incredibly large feet and very long limbs. So, it was probably quite fast by dinosaur standards.”

The Enigmacursor skeleton at the Natural History Museum in London

© The Trustees of the Natural History Museum, London

That is where the “cursor” part of its name comes from: it means “runner”. Maidment says it was probably charging around in the shadows of behemoths like Diplodocus and Stegosaurus.

The specimen’s vertebrae weren’t fused, which implies it wasn’t fully mature when it died. “I think this animal was probably a teenager, but it may well have been sexually mature, so it might not have got that much bigger,” says Maidment.

“Enigmacursor represents one of the rarities from further down the food chain of the dinosaur era,” says David Norman at the University of Cambridge. “This newly described animal was clearly a small, wallaby-sized herbivore that scampered around the Late Jurassic countryside.”

The discovery sheds light on the early evolutionary stages of the herbivorous dinosaurs that would go on to dominate Cretaceous ecosystems in North America, says Maidment, and helps us build a more realistic ecological picture of the life and times of dinosaurs.

Journal reference:

Royal Society Open Science DOI: 10.1098/rsos.242195

LIFE | JUN 24, 2025, 8:01 PM EDT | VIEW ON NEW SCIENTIST

Enigmatic lizards somehow survived near Chicxulub asteroid impact

The night lizards may have been the only terrestrial vertebrates that survived in the region of the asteroid impact 66 million years ago, which led to the extinction of non-avian dinosaurs

By James Woodford

A yellow-spotted tropical night lizard (Lepidophyma flavimaculatum)

Dante Fenolio/SCIENCE PHOTO LIBRARY

A small, secretive group of lizards that still exists today may have been the only terrestrial vertebrates that survived in the vicinity of the Chicxulub asteroid collision, which led to the extinction of the non-avian dinosaurs.

It has long been known that xantusiid night lizards are an ancient lineage that have persisted for tens of millions of years. But Chase Brownstein at Yale University and his colleagues suspected that the group may have actually arisen earlier than previously thought: in the Cretaceous Period, which ended around 66 million years ago.

The end of the Cretaceous was marked by a giant asteroid strike in the vicinity of Yucatán peninsula in Mexico, which left a crater over 150 kilometres wide and caused the extinction of most of the animal and plant species across the world.

Today, the night lizards – a misnomer, as they aren’t actually nocturnal – are still found in Cuba, Central America and the south-west of the US.

Brownstein and his team used previously published DNA sequence data for xantusiids to create an evolutionary tree for the group. They combined this with skeletal anatomy across living and fossil night lizards, allowing the team to determine how old their lineages are and estimate how many offspring the ancestral night lizards would have produced.

They found that the most recent common ancestor of living xantusiids emerged deep within the Cretaceous, over 93 million years ago, and they probably only had clutches of one or two offspring.

“I think it is very possible that these ancient populations were as close or closer to the impact site than those today,” says Brownstein. “It’s almost as if xantusiid distribution sketches a circle around the impact site.”

Based on fossil evidence, it is unlikely that the ancient night lizards simply recolonised the region later on, says Brownstein.

“We know from our reconstructions that the common ancestor of living species was almost certainly living in North America, where the fossil record of xantusiids is pretty much fairly continuous on either side of the boundary layer marking the impact,” he says.

Many night lizard species live in rock crevices and their slow metabolisms are comparable to those of other survivors of the mass extinction, such as turtles and crocodiles. “This, perhaps, would have allowed them to take shelter during the impact and its immediate aftermath,” says Brownstein.

Nathan Lo at the University of Sydney says the lizards are remarkable. “They lived in the region around the asteroid’s point of impact, [yet] they managed to survive, even though the asteroid would have wiped out organisms that were within hundreds of kilometres of the impact point.”

They managed this despite not having many of the usual traits that we would expect to see in survivors of mass extinctions. “The species that tend to survive through these extinction events are those that are small in size, reproduce quickly and that have large geographic ranges,” says Lo. “But these lizards generally reproduce slowly and seem to have quite small ranges.”

Journal reference:

Biology Letters DOI: 10.1098/rsbl.2025.0157

HEALTH | JUN 24, 2025, 5:20 PM EDT | VIEW ON NEW SCIENTIST

Women's pelvises are shrinking – how is that changing childbirth?

Over the past 150 years, the rise in Caesarean sections and changes in diet could have led to smaller pelvises among women – which may make vaginal birth more difficult but could also reduce common conditions associated with childbirth

By Michael Marshall

Medical advances have changed childbirth – potentially enough to impact human evolution

FatCamera/Getty Images

Women’s pelvises have become narrower over the past 150 years, according to a study of over 8000 people from three countries. There are many factors at play, but whatever the ultimate cause, it is the latest piece of evidence leading researchers to rethink the “obstetrical dilemma”, a description of the competing evolutionary pressures on pelvis size: the need to accommodate babies’ large heads drives pelvises to widen, but the need to walk bipedally pushes them to narrow.

We don’t know exactly what is driving this change, or all the ways it will affect people’s health. But if pelvises continue shrinking at this pace, it could make Caesarean sections more likely out of necessity – which could have a host of knock-on effects.

Maciej Henneberg at the University of Adelaide in Australia and his colleagues reanalysed an existing dataset of 1247 Australian women, born between 1900 and 1984, and found that pelvic width decreased by 0.42 millimetres per year. Likewise, among 3486 Polish women, pelvis widths decreased by 0.47 mm per year between 1880 and 1970, and among 320 Mexican women, pelvis width shrank by 0.42 mm per year between 1900 and 1970. In the same time periods, average height increased and shoulder width either held steady or increased.

“Given that in these different regions, it evolved in the same direction, even though body height increased, I personally find this convincing,” says Philipp Mitteroecker at the University of Vienna in Austria.

“The dataset is fantastic,” says Lia Betti at University College London.

For Henneberg, this finding shows that modern medicine is weakening natural selection’s impact on the human pelvis – and especially on the width of the birth canal. In the past, if a baby was too large or the birth canal was too narrow, both mother and baby would probably die in childbirth. However, safe and effective Caesarean sections, or C-sections – in which the baby is removed surgically through the abdomen – mean this evolutionary pressure is reduced. As a result, birth canals and pelvises can become narrower.

Mitteroecker also thinks C-sections are changing the evolutionary pressures at work on the human birth canal. He predicted that this might drive pelvises to narrow in a 2016 analysis, and says this is the latest iteration of a long-standing phenomenon.

“Midwifery is old,” he says, and “really unique to humans”. Women have been getting help with childbirth, often from other women, for hundreds of thousands of years. This cultural practice has relaxed the selection pressure on the pelvis and birth canal – so our behaviours have affected our own biological evolution. “C-section is, in a way, an extreme form of that,” says Mitteroecker. C-sections took off starting in the 1970s through the 1990s, and the global rate increased from 7 per cent in 1990 to 21 per cent in 2021.

However, Betti is sceptical that C-sections are the main explanation for the recent change in pelvic width. She points out that humans got a lot taller in the same time frame, but that is probably due to diet and better healthcare – not an evolutionary change in our genes.

“We know that diet can affect the pelvis,” says Betti. When nutrition is scarce, our developing bodies tend to allocate more nutrients to certain organs, including the brain, at the expense of others. But now we have ample nutrition, so our bodies may have reallocated nutrients. “So we end up with different body proportions,” says Betti. “That’s quite possible.”

Finding an explanation for our narrowing pelvises could help us understand why human childbirth is so difficult – which brings us back to the obstetrical dilemma. However, the exact nature of the dilemma has been disputed. In a 2024 study, Mitteroecker and his colleagues found that the pelvic floor, not walking, was probably the key driver towards narrowness: wider pelvises increase the already high pressure on the pelvic floor, boosting the risk of prolapses and incontinence.

Or both influences could be at work. A study of 31,000 people, published in April, linked wider pelvises to easier births, but also slower walking and a greater risk of pelvic floor conditions.

There could be even more influences in this dilemma. Betti argues that our pelvises are sensitive to many factors in the environment, such as temperature. Other researchers have described a “new obstetrical dilemma” linked to rising rates of obesity, which can make babies larger. The real answer is probably some combination of factors, says Betti: she says some researchers have rebranded the dilemma as a “multifactor pelvis”.

Narrower pelvises will affect human health. They will make vaginal childbirth more difficult, potentially leading to even more C-sections. “Who knows how long it will take to get to the state that there will be no children born naturally?” says Renata Henneberg, part of the team behind the new research and Maciej Henneberg’s wife.

At the same time, narrower pelvises may reduce the risk of pelvic floor problems, which can be very harmful. Childbirth, says Betti, can have “very unpleasant, long-lasting effects, which can affect very negatively the life of a woman”.

However, she says predicting what will happen is difficult, again because so many factors are in play: people are having fewer children, which might reduce the risk of injury, but they are also having them later. “A lot of things have changed at the same time,” she says.

Reference:

Research Square DOI: 10.21203/rs.3.rs-6712615/v1

TECHNOLOGY | JUN 24, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

Leonardo da Vinci's 'helicopter' design could make drones quieter

A simulation of the "aerial screw" designed by Leonardo da Vinci in 1480 suggests it would use less power than modern drone rotors to generate the same lift, and make less noise too

By Alex Wilkins

Leonardo da Vinci’s sketch of the aerial screw

Gianni Dagli Orti/Shutterstock

A flying machine designed by Leonardo da Vinci may have been functional and much quieter than modern drone designs.

Rajat Mittal at Johns Hopkins University in Maryland and his colleagues have found that da Vinci’s “aerial screw”, which he proposed while working as a military engineer in the 1480s but never built or tested, may require less power to generate the same amount of lift as a conventional drone rotor.

The machine is similar to an Archimedes’ screw, a helix-shaped pump that transports water as it rotates. Da Vinci envisaged the aerial screw as being powered by humans, which would have made it challenging to get off the ground due to weight. But with light electric motors spinning the rotor, it could have actually flown.

Mittal and his team built a simulation of the screw and put it in a virtual wind tunnel to see how it would perform while hovering in place, testing it at different rotational speeds and comparing it with a conventional drone rotor with two blades.

They found the aerial screw could generate the same amount of lift while rotating more slowly, meaning it would consume less power.

By measuring the pressure and wind flow patterns that moved around the virtual screw, Mittal and his team could also calculate how much sound it might produce, which they found was less than the conventional design for the same amount of lift.

“We were surprised,” says Mittal. “We went in thinking that because the shape of this spiral screw is just completely, in some sense, ad hoc, it was intuitive that the aerodynamic performance would be so bad that we would not be able to get any improvements over conventional blades.”

Mittal and his team now want to see if they can improve upon da Vinci’s design to make it more efficient while keeping its noise-reducing qualities, he says.

As drones are increasingly used in cities, such as for home deliveries or emergency services, noise pollution has become more of a problem, leading to researchers looking for new rotor designs that create less noise for a similar amount of lift.

“The authors do a good job of stating that if you can create the same thrust by turning slower, which the da Vinci [rotor] does, then the noise is going to be less,” says Sheryl Grace at Boston University in Massachusetts. “It doesn’t have to be the da Vinci design to achieve this, but it is nice that da Vinci’s does.”

However, to show that da Vinci’s design could be useful in real-world scenarios, they would need to test how it performs while flying through the air, rather than just hovering, as well as consider how the extra weight of the rotor might affect performance, says Grace.

Reference:

arXiv DOI: arXiv:2506.10223

The science of the Renaissance: Italy

Encounter the great scientific minds and discoveries of the Renaissance, which helped cement Italy’s role at the forefront of scientific endeavour.

Find out more

ENVIRONMENT | JUN 24, 2025, 7:00 AM EDT | VIEW ON NEW SCIENTIST

Earth is more sensitive to greenhouse gases than we thought

Our climate seems to be more sensitive to greenhouse gas emissions than some researchers had hoped, meaning the world will have to up its decarbonisation efforts

By Madeleine Cuff

Climate change could be even worse than we thought

Kapook2981/Getty Images

Earth’s climate may be more sensitive to pollution from greenhouse gas emissions than we had hoped, which could mean limiting the rise in global temperature to less than 2°C will be more difficult.

This is “bad news” for global efforts to tackle climate change, says Gunnar Myhre at the CICERO Center for International Climate Research in Norway.

Researchers have known for decades that pumping greenhouse gases into Earth’s atmosphere will warm the climate, with far-reaching consequences. But what scientists do not know for sure is how much warming we can expect as a consequence of this pollution. In other words, how sensitive is Earth’s climate to these emissions?

The main uncertainty stems from the question of how clouds will respond to a warming atmosphere, as shifts in cloud systems can amplify the warming effect in a vicious feedback loop.

Most estimates of how much warming we can expect by the end of the century are based on running climate models with a range of sensitivity assumptions. Models used by the Intergovernmental Panel on Climate Change suggest that a doubling of atmospheric CO₂ concentrations relative to pre-industrial levels would produce between 2°C and 5°C of warming, with the organisation settling on a central estimate of 3°C.

Alongside his colleagues, Myhre set out to compare predictions from these climate models against satellite readings of Earth’s energy imbalance. This is a measure of how much surplus heat is in our climate system, and it gives an indication of the sensitivity level of the global climate.

The team found that climate models with low sensitivity – those that suggest Earth’s climate is more resistant to greenhouse gases in the atmosphere – don’t match satellite records gathered since the turn of the millennium. Models with a higher level of sensitivity, suggesting Earth’s climate is less resistant to these gases, more closely match observations, says Myhre. “The optimistic models that would give us a small amount of warming are more unlikely,” he says.

The findings call into question the accuracy of climate models that predict less than 2.9°C of warming for a doubling of atmospheric CO₂. Instead, they suggest warming above this level is more likely for the same amount of pollution.

This also tallies with recent record-breaking temperatures recorded over land and sea since 2023, which “point towards a stronger climate feedback” in the atmosphere, says Myhre.

A more sensitive climate means emissions must fall faster to maintain the same temperature trajectory. In short, the world has to decarbonise further and faster to fulfil its climate commitments.

Johannes Quaas at the University of Leipzig in Germany says the research presents a “very plausible argument” that Earth is more sensitive to warming than some models suggest, adding that it has “narrowed the range” of model estimates that scientists should work from. “It underlines the need for political action against climate change.”

Richard Allen at the University of Reading in the UK points out that the satellite record only began in 2001, so “natural climate fluctuations” could also form part of the story. Nevertheless, he says the study is “rigorous” and “adds more evidence that simulations which predict less warming in the long term are less realistic”.

Journal reference:

Science DOI: 10.1126/science.adt0647

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- Why is it seemingly impossible to stop phone thieves?: 2025 Jun 23

COLUMNIST TECHNOLOGY | JUN 25, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

Forget the Terminators, our robot future may be squishy and fun

It is uncanny how human fears about robots mirror those about immigrants. But maybe they aren't out to take our jobs or destroy us all, says Annalee Newitz

By Annalee Newitz

“When I think about the future of robots and society, I don’t see machine overlords”

Miguel Medina/AFP via Getty Images

Are you worried that AI-powered robots are going to steal our jobs and maybe kill us all? You aren’t alone. But it is time to play devil’s advocate with yourself and consider whether the opposite might be true.

My new novel, Automatic Noodle, out later this year, is about four robots who struggle to find employment in a country where humans have made laws preventing bots from unionising, opening bank accounts, voting and owning their own businesses. Yes, it is science fiction. But it is based on real tech – and, more importantly, it explores the implications of our deeply held suspicion that robots are evil.

I have spent years writing non-fiction about real-life robots, interviewing roboticists and engineers to find out what is coming next. Recently, I visited an incredible lab at Yale University called the Faboratory, where Rebecca Kramer-Bottiglio heads up a team developing soft robots. These include bendy, squishy, pneumatic creatures with circuits made from liquid metal. One swims like a turtle and could be used for environmental monitoring in swampy areas. Another, called a tensegrity robot, looks like a bundle of plastic sticks held together with stretchy rubber. Drop it from a height and it will bounce, rolling around to check out its surroundings.

Medha Goyal, a researcher at the Faboratory, showed me minuscule balls of fluid that expand as they warm up. Eventually, thousands of these “granular actuators” could be used inside a robot, expanding and contracting to create stiffness or softness in a limb. They could also turn out to have medical applications, pushing tiny robots around inside your body to deliver medicine or diagnose a problem.

The point is, Kramer-Bottiglio and her colleagues are challenging the very idea of what a robot is. Tomorrow’s bots probably won’t look like giant humanoids; instead, they might be soft little guys, tumbling around using pneumatics instead of metal gears. Indeed, one of the robots in my book is an octopus-shaped soft robot, designed for search-and-rescue missions in the water. This octobot’s name is Cayenne, and they are able to taste things using sensors on each arm.

Tomorrow’s bots probably won’t look like giant humanoids; they might be soft little guys instead

When I imagine the future of robots, I see the likes of Cayenne. All they and their robot friends want is to run a noodle restaurant in San Francisco. Their robo-pals include a three-legged, wheeled bot named Sweetie; one named Hands who is nothing but a mixer with two arms attached; and Staybehind, a humanoid-ish soldier bot who would rather decorate the restaurant than fight a war. They make a ragtag family.

This family lives at a unique time in human history. In the 2060s, the government of the new nation of California has decreed that some AI-powered robots are basically people. But politicians worry that robots with the same rights as humans will multiply unchecked, rapidly taking over everything. So they deprive them of key rights “for their own good”, promising that humans can vote to expand robot rights later.

Despite what their human neighbours think, Cayenne and friends don’t want to take over the world. In fact, they only want to keep doing the jobs they already had. Except instead of making crap food for a distant human master, they will make something they love, with care, because they truly want to do it. They are basically immigrants in a new country, trying to survive in a nation that at best mistrusts them and at worst wants them dead.

I use this metaphor deliberately, because it is uncanny how much stereotypes about immigrants mirror human fears about robots. They will steal our jobs. They will rise up and destroy us. They will degrade the fabric of our culture. What is striking is that people who say these things about immigrants have often never spent time getting to know them. Meanwhile, people hold the same ideas about robots that don’t even exist yet. It seems like a pattern. These are the kinds of fears we have about groups we imagine without ever doing any research about the reality of who they are. Or, in the case of robots, who they might be.

And that is why, when I think about the future of robots and society, I don’t see machine overlords. I see reality obscured by scary fantasies and freedoms constrained by laws based on those fantasies. I see soft-bodied creatures and turtles and pneumatic arms, not Terminators. I see Cayenne, who lives in fear because of human hate and robophobic vigilance committees posting deepfakes online about made-up robot crimes.

Humans are masterminds at preparing for futures that are highly unlikely, while ignoring ones unfolding before our very eyes. But we don’t have to be that way. We can try to make plans based on evidence and science, rather than surreal nightmares that never come true.

Annalee’s week

What I’m reading

Tochi Onyebuchi’s Racebook: A personal history of the internet, a totally engrossing essay collection about cosplay, video games and social media.

What I’m watching

Murderbot, obviously.

What I’m working on

Hanging out with archaeologists at the Punic/Roman town of Tharros on Sardinia in Italy. More on that later!

Annalee Newitz is a science journalist and author and their latest book is Automatic Noodle. They are the co-host of the Hugo-winning podcast Our Opinions Are Correct. You can follow them @annaleen and their website is techsploitation.com

The art and science of writing science fiction

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TECHNOLOGY | JUN 23, 2025, 8:00 AM EDT | VIEW ON NEW SCIENTIST

Why is it seemingly impossible to stop phone thieves?

The huge market for stolen smartphones means that thieves will continue to snatch them, but is there anything we can do to put a stop to this crime wave?

By Matthew Sparkes

London is a phone-theft hotspot

Jeff Blackler/Shutterstock

Even if you have never had your smartphone stolen, you probably know someone who has. In London, 80,000 phones were stolen last year alone. And as victims of phone theft know, while the loss of a pricey gadget can sting, the dreary administrative slog in replacing a device that runs your entire life can, in some ways, be worse. So why can’t we stop phone thieves – and is there a better way to protect your personal data?

The answer is partly down to the numerous ways that criminals profit from stolen phones, but it is also about technology firms prioritising usability over security and international governments failing to arrive at a global solution. In short, it’s complicated.

Some victims place the blame with the police for failing to catch phone thieves. When Nav Dugmore from Wolverhampton, UK, travelled to London for the first time, she had her iPhone snatched seconds after leaving Euston train station, a major transport hub. “It traumatised me, if I’m honest,” she says. “There needs to be something else put in place to stop them being able to use your phone, and I think the police need to be doing more.”

London’s Metropolitan Police told her that several other thefts had happened at the same spot in the previous hour and admitted there was “no chance” of recovery. Dugmore had the phone’s face-recognition security setting turned on, but the device was unlocked when it was grabbed and the thief quickly spent £300 in various shops around London. By far the biggest blow was the loss of photos of her three children growing up, she says, which weren’t backed up.

When a phone like Dugmore’s is stolen, it enters a conveyor belt of crime, with multiple possible destinations. The simplest route is the thief simply selling the handset on, often to be resold in another country. Phones can be sold for parts to unscrupulous repair shops, too. Daniel Green, an inspector at the City of London Police, says phone snatchers have links to gangs that export the devices, essentially smuggling them out the same way as drugs are smuggled in. “What we’ve found suggests boxes and boxes of phones going out [of the country],” he says.

Then there are more involved scams, like removing the SIM card that identifies a phone to the network and placing it into another handset. This allows criminals to read text messages destined for the victim and can get them access to email and websites that use two-factor authentication. This can be combatted by setting up a PIN for your SIM card, but this must be done before the phone is stolen.

The most valuable phone for thieves to target is one with no security protections, but even setting a PIN on your handset won’t necessarily protect you, says James O’Sullivan, who runs an app called Nuke designed to help people in the aftermath of their phone being stolen. Thieves may simply look over your shoulder to see your PIN, or use more devious tricks. For instance, activating an iPhone’s Emergency SOS feature and then cancelling it will temporarily disable access via face or fingerprint recognition, forcing you to input your PIN the next time you unlock it. A clever thief can offer to take a photo for you, surreptitiously pull this trick, then snoop when you enter your PIN after they hand back the phone.

With unlocked access, criminal options become even more sophisticated. Thieves can steal money from online banking apps or cryptocurrency wallets, then message the victim’s friends and family to scam them into sending emergency funds. They can even post nefarious links on social media accounts to phish others into providing their logins or private data.

So what can be done? The UK government at least recognises that there is a problem. It launched a crackdown late last year, promising to pressurise smartphone manufacturers to permanently disable stolen phones. It also pledged to conduct an investigation to learn more about the people who steal phones, where the devices end up and how to stop the problem.

In theory, the technology already exists to disable stolen phones. Each device carries a unique IMEI code and those reported stolen can be blocked from cell phone networks, which already happens on a per-country basis in places including the UK, Canada and the US. But a phone blocked in this way can still access the internet through Wi-Fi connections. The Met Police has long urged technology firms to build on this and also block access to cloud services from those handsets, such as data backup and photo storage, which would reduce their functionality and make them less attractive to thieves. So far, Apple and Google have declined to do so.

Even this wouldn’t help if such restrictions continue to operate on a per-country basis, as is the case with IMEI blocks now, as criminals can simply send phones to a country where they aren’t blocked. Green says he would like to see manufacturers create a permanent kill switch for devices, to completely remove the incentive for criminals to take phones. “I don’t know whether it’s just not a problem for them,” he says. “More pressure needs to be put on them. We’re trying to pick up the pieces on our end and it’s very, very difficult.”

Jordan Hare, a former police digital forensics expert who now works at private security firm S-RM, says phones are already equipped with security features that should keep even the most determined crooks at bay. For example, some phones automatically lock if they detect a sudden jerking movement, like being snatched by a thief.

The problem is that many of these options are turned off by default – something Hare suspects is done to make life as simple and seamless as possible for users. “An opt-in for these features actually doesn’t help the general consumer because they don’t necessarily know they’re there,” he says. “Whereas an opt-out scheme, having them on by default, having better information provided when you first set up your phone about ‘this setting is on, this is what it does, this is why you shouldn’t turn it off’, for example, actually puts measures in place ahead of a phone being stolen.”

Meanwhile, other security features that sound promising, like the ability to track the current location of your phone from a web browser, simply fail to make a difference in the real world. If a phone is tracked to a large block of flats, there is little police officers can do without further information because it isn’t possible to get such a wide-ranging search warrant.

That was certainly Dugmore’s experience with her stolen iPhone. “The last location was about 10 miles away from where my phone was stolen,” she says. “The police did say ‘there’s no chance of you getting that phone back’.” When asked about the incident, the Metropolitan Police told New Scientist: “Unfortunately the investigation couldn’t be progressed further due to a lack of CCTV in the area. We recognise the victim’s frustration.”

Most major smartphone venders didn’t respond to a request for comment by New Scientist, with Samsung, Xiaomi and Google failing to reply. Apple did respond, however.

“We have been working on this issue from a hardware, software and customer-support standpoint for more than the last decade,” says an Apple spokesperson. “We have made and continue to make significant investments to create industry-leading tools and features that put control in the hands of our users in the event of theft.” The spokesperson declined to explain why some security options aren’t turned on by default.

Ultimately, the only way to prevent smartphone theft – other than being careful whenever you use your device in public – is for manufacturers to make it not worth criminal’s while. They have control over the hardware and software, and could bring in unhackable features that completely lock down a phone, its apps and its spare parts from abuse or resale. But O’Sullivan says it just doesn’t seem to be a priority. “If I’m brutally honest, it’s probably not their biggest thing, because stolen phones are reasonably good business for people that are selling new phones.”

Space

- Read an extract from Adam Roberts’s far future-set Lake of Darkness: 2025 Jun 27

- Weird line of galaxies may have been created by a cosmic bullet (paid): 2025 Jun 24

- Vera Rubin Observatory has already found thousands of new asteroids: 2025 Jun 23

- Stellar flares may hamper search for life in promising star system (paid): 2025 Jun 23

- Stunning first images show the power of the Vera C. Rubin Observatory: 2025 Jun 23

SPACE | JUN 27, 2025, 5:45 AM EDT | VIEW ON NEW SCIENTIST

Read an extract from Adam Roberts’s far future-set Lake of Darkness

In this passage from near the opening of Lake of Darkness, the latest read for the New Scientist Book Club, we are given an insight into how deep-space travel works in Adam Roberts’s universe

By Adam Roberts

Lake of Darkness is the New Scientist Book Club’s July pick

You were born, in all likelihood, towards the end of the 20th– or towards the beginning of the 21st-centuries. Yes? I have no desire to condescend to you. Many of the features of life today will be readily comprehensible to you, if you can only — as surely you can — extrapolate from your past into our present with a little common sense.

Take the ship. There are lots of imaginary startships in your popular culture, but many of these are only vaguely thought-through: naval ships, or land-based buildings, foolishly projected into deep space. Corridors? Why would we want corridors in a startship? Rigid external superstructures and frame, containing decks and floor — very fragile, under the kinds of shearing forces and pressures of spaceflight. But you already knew this, if you thought about it for a moment. The Sβ Oubliette did not look like a skyscraper lying on its side, or a pyramidically-stacked aircraft carrier. It looked, if you prefer an aquatic analogy, like one of those semi lucent glittering blobs that pulse through the depths of the ocean.

Some of a startship is its drive and power-systems: propulsion, guidance and AI. But most of it — nine-tenths, as I mentioned above — is a hospital. Human animals are not built for living in space, and any enterprise that puts human beings in space for long stretches of time must spend most of its time attending to the health of those humans. This is not — or, let’s say, it is rarely — a matter of broken bone, or infectious disease, as with older mundane hospitals. It is a congeries of related problems, chief amongst them radiation poisoning and bone-health from calcium loss, with modal health, mental-emotional well-being and temporal dysphasia coming close behind. Deep space is suffused with high levels of various rays and fields that degrade the human body on a cellular level: burns, mutations, cancers, decadences. Much of a deep space mission is attending to these injuries. Cancer cannot be inoculated against, but it can be treated. Cellular and DNA damage cannot be prevented, but can be addressed post hoc. Psychological derangement and distress, and spiritual emptiness, are perennials, and more likely to occur in the constricted environments of a startship than in the stimulus-rich homes and habitats of our utopian collectives, but even they can be coaxed back towards wholeness and health by the right strategies. Solace is possible. And so the mission goes on. For the crew, about a third of their waking hours are given over to ship’s business, a third to health-checks and treatments, leaving a few hours of leisure time per artificial day.

In the case of a ship’s emergency — as now, aboard the Sβ Oubliette — the leisure time is eaten into, and the duty absorbs more of the day. But the healthcare is never stinted.

As for corridors: the interior of any given startship will be different, depending on design and purpose and aesthetics, but the basic structure is a cluster of moveable Meissner tetrahedra, linked together with smartcable. The interiors of these structures, being non-spheres of uniform diameter, are spun in a complex of spiral trajectories to mimic gravity. It’s a poor imitation, and extra work pushing limbs in exercise bands, compressing the body and — most of all — addressing calcium loss and density with medical interventions are also needful. But Meissner bodies make more livable interiors than the circular strips of ribbon rotated like merry-go-round, like in your moving-along picture show Two Thousand And One Odysseys. Those are very tricky to live in, believe me. Some places do operate them: usually as temporary structures while larger, more stable ones are being built. But you wouldn’t want to live in such a rotating strip. Turn around suddenly — turn your head too quickly — and you’ll start puking. Large-diameter slow-spinning Meissner bodies, by slowly moving the 3D space on an in-logic inaround, is a much more tolerable arrangement.

You don’t care about any of that. Why would you?

This is an extract from Adam Roberts’s Lake of Darkness (Gollancz), the latest pick for the New Scientist Book Club. Sign up and read along with us here.

Explore the world of science fiction and learn how to craft your own captivating sci-fi tales on this immersive weekend break, with author Adam Roberts.

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SPACE | JUN 24, 2025, 11:00 AM EDT | VIEW ON NEW SCIENTIST

Weird line of galaxies may have been created by a cosmic bullet

A high-speed crash between two dwarf galaxies might explain a unique feature in space – and provide useful information on dark matter

By Jonathan O’Callaghan

A line of galaxies formed after two dwarf galaxies collided head-on, ripping gas from each other

Keim et al./DECaLS

A strange line of dwarf galaxies may have been the result of a bullet-like cosmic collision.

Michael Keim at Yale University and his colleagues used the Keck Observatory in Hawaii to study a unique trail of 12 small and faint dwarf galaxies about 75 million light years from the Milky Way.

The orientation and speed of the galaxies suggest they originated from a head-on collision between two galaxies in a group called NGC 1052. The collision left gas in its wake, which eventually clumped into groups of stars under gravity.

“They’re very unique,” says Keim. “It’s the only system like this that’s known.”

There is a similar collection of larger galaxies called the Bullet Cluster, so Keim and his colleagues have nicknamed this system the “bullet dwarf”.

The two galaxies are thought to have crashed into each other at 350 kilometres per second relative to each other about 9 billion years ago. As they passed through one another, gas was ripped from each galaxy. “It’s unlikely that two stars will collide,” says Keim. “But that’s not true for clouds of gas.”

Curiously, each of the clumps of stars left behind from the collision is devoid of dark matter. This is very unusual as most galaxies have a large amount of dark matter, sometimes accounting for more than 90 per cent of their total mass.

Keim and his team think this might be because while the gas was torn from the galaxies, dark matter does not interact with matter – or even itself – so it was unaffected.

That could refute alternative ideas for dark matter that suggest our evidence for its gravitational influence result from a mismeasurement of how stars and galaxies behave. “This is saying dark matter is a particle, and it can become separated from a galaxy,” says Keim.

Reference:

arXiv DOI: 10.48550/arXiv.2506.10220

The world capital of astronomy: Chile

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

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SPACE | JUN 23, 2025, 3:46 PM EDT | VIEW ON NEW SCIENTIST

Vera Rubin Observatory has already found thousands of new asteroids

In just 10 hours of observing the night sky, the powerful new telescope detected more than 2000 new asteroids, including a few that will pass near Earth

By James Dinneen

Link to video: https://www.youtube.com/watch?v=qgQ2LCpkifg

Amid the millions of distant stars and galaxies captured in the first images released from the Vera C. Rubin Observatory are thousands of never-before-seen asteroids whizzing around the solar system.

“These two beautiful galaxies were photobombed by asteroids,” said Željko Ivezić at the University of Washington in Seattle, presenting an image showing several asteroids streaking past two spiral-armed galaxies during a press briefing on 23 June.

During just 10 hours of observing the night sky, the telescope – situated in the clear air high atop a mountain in the Chilean Andes – captured 2104 previously unknown asteroids. Of these, seven are on a trajectory that would pass near Earth, though none pose a risk of hitting us, said Ivezić.

Researchers identified and tracked newly discovered asteroids in images taken over 10 hours

NSF-DOE Vera C. Rubin Observatory

The telescope was not primarily designed to detect near-Earth objects, but to conduct a decade-long survey expanding our view of the entire universe. But the same qualities that make it useful for that purpose are also good for asteroid detection: “You need to scan the sky very fast, with a very large field of view, for a long time,” said Ivezić.

The asteroids were identified by scanning the same region of sky and noting what was moving. In a composite image Ivezić displayed during the briefing, the asteroids appeared as coloured streaks on a background of bright objects in deeper space. This gives us a better picture of our planetary neighbourhood and its inhabitants. “They were not a surprise,” he said. “We have exquisite simulations.”

During the course of its 10-year survey, the telescope is expected to detect about 5 million new asteroids, quintupling the number identified in previous centuries of searching.

Asteroids are marked in coloured dots in front of an image of galaxies visible in the southern sky

NSF-DOE Vera C. Rubin Observatory Copyright: NSF-DOE Vera C. Rubin Observatory

Any new detections will be reported on a daily basis to the Minor Planet Center in the US, which will analyse their orbital trajectories and identify any objects that could pose a threat to Earth. “Within 24 hours, everyone in the world will know that there is a particular object which could be hazardous,” says Ivezić.

Matthew Payne at the Minor Planet Center says only an estimated 40 per cent or so of the near-Earth objects large enough to pose a threat have been found. The radical increase in the number of detections from the Vera Rubin Observatory will help quickly find the rest of them, he says.

The huge increase in observations of other objects in the solar system – from the Main Belt asteroids between Mars and Jupiter to objects further out beyond the orbit of Neptune – is also expected to give us new insight into our immediate cosmic neighborhood. “It will revolutionise, broadly, solar system science,” says Payne.

The world capital of astronomy: Chile

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

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SPACE | JUN 23, 2025, 10:00 AM EDT | VIEW ON NEW SCIENTIST

Stellar flares may hamper search for life in promising star system

Astronomers have been trying to detect atmospheres on planets orbiting TRAPPIST-1, but bursts of radiation from the star make this challenging

By Alex Wilkins

Illustration of TRAPPIST-1, a red-dwarf star with at least seven orbiting planets

Mark Garlick/Alamy

The search for atmospheres around the TRAPPIST-1 star system, one of the most promising locations for life elsewhere in the galaxy, might be even more difficult than astronomers first thought because of short-lived radiation blasts from the star.

TRAPPIST-1, first discovered in 2016, is a small red dwarf star about 40 light years from Earth with at least seven planets orbiting it. It is a prime target for astronomers hoping to detect extraterrestrial life because several of its planets appear to sit in a habitable zone where temperatures are just right for liquid water.

But in order to support life, those planets would have to retain atmospheres. So far, extensive observations with the James Webb Space Telescope have failed to find evidence of atmospheres on any of the planets.

Now, Julien de Wit at the Massachusetts Institute of Technology and his colleagues have detected microflares coming from the TRAPPIST-1 star every hour or so that last for several minutes. These tiny bursts of radiation appear to interfere with our ability to observe the light that passes through the planets’ atmospheres – if they exist – thwarting the main method of detecting what chemicals might be in any atmospheres.

Using the Hubble Space Telescope, de Wit and his team looked for a specific wavelength of ultraviolet light coming from TRAPPIST-1 that is absorbed by hydrogen. If they saw less of this light than expected when a planet passed in front of the star, then it might have suggested hydrogen leaking from the planet’s atmosphere.

They didn’t find any signs of this, but they did find significant variability between different observations, suggesting that extra light was coming from somewhere at certain times. Because the Hubble data can be broken up into 5-minute chunks, they could see the extra light was very short-lived. De Wit and his team say the source must be microflares – bursts of radiation from the star, like the solar flares on our sun but more frequent.

The TRAPPIST-1 star is extremely faint, meaning that astronomers need to observe it for a long time to collect enough light. “On top of that, there is this flaring activity, on a timescale that’s relevant to the timescales of transiting planets,” says de Wit. “It seems like it’s really very difficult to get to say anything truly informative about the presence of [atmospheres on the exoplanets],” says de Wit.

He and his colleagues also calculated whether these flares could affect the planets’ ability to hold on to atmospheres. One planet, TRAPPIST-1b, on which the James Webb Space Telescope had already failed to find evidence of an atmosphere, could be losing the equivalent of 1000 times all the hydrogen in Earth’s oceans roughly every million years, they found. However, there are still a lot of unknowns and a wide range of different scenarios, says de Wit, partly because we don’t know how many of these flares are actually hitting the planets.

Stars like this can have a range of activity levels, but it seems as if TRAPPIST-1 might be towards the more active side of this range, says Ekaterina Ilin at the Netherlands Institute for Radio Astronomy. “It’s not like it’s an absolutely unexpected, otherworldly result; it’s just kind of bad luck. It’s more active than we hoped it would be,” she says. “In a way, it’s genuinely new to see these flares, or what we at least interpret as this, if they are what they think they are. It might be one of the first instances in a star that small.”

Reference:

arXiv DOI: 10.48550/arXiv.2506.12140

SPACE | JUN 23, 2025, 1:00 AM EDT | VIEW ON NEW SCIENTIST

Stunning first images show the power of the Vera C. Rubin Observatory

A powerful new telescope in Chile is set to transform astronomy, and its first pictures of stellar nurseries and galaxies have just been unveiled

By Alex Wilkins

The Trifid (upper-right) and Lagoon (centre) Nebulae as viewed with the Vera C. Rubin Observatory

NSF-DOE Vera C. Rubin Observatory

A pink-and-blue feast of stellar nurseries and a dense cluster of our neighbouring galaxies appear in the first glimpses of space from the Vera C. Rubin Observatory, which is set to transform our understanding of the universe with unprecedentedly detailed scans of the night sky.

Link to video: https://www.youtube.com/watch?v=dDZ8pIOlNQc

These images, which were compiled from around 10 hours of observation from the Cerro Pachón mountain in Chile, are tests that illustrate the sorts of shots Rubin is capable of capturing. The telescope’s decade-long mission to observe the night sky each night, known as the Legacy Survey of Space and Time, will start later this year.

The first image (above) contains the Trifid Nebula, the pink-and-blue ball in the upper-right quarter, which is a star-forming region in our galaxy surrounded by thousands of young stars. In the centre of the shot is the Lagoon Nebula, a vast cloud of interstellar gas and dust. To create this image, astronomers combined 678 different pictures taken over 7 hours by Rubin.

A small section of the Vera C. Rubin Observatory’s total view of the Virgo cluster

NSF-DOE Vera C. Rubin Observatory

The second image is a close-up of the Virgo cluster, a network of thousands of galaxies that has been known to astronomers for centuries. While its brightest members can be seen with simple telescopes, Rubin’s view shows the entire cluster and the galaxies around it in extreme detail. The full zoomed-out image, which can be seen in the video above, reveals around 10 million galaxies.

These are just 0.5 per cent of the 20 billion galaxies that Rubin will observe over its lifetime, helping shed light on mysteries such as dark matter and the possible existence of another planet in our solar system, known as Planet Nine.

The telescope’s science team has also built a tool called Skyviewer, which is available to the public. It lets viewers explore these extremely high-resolution images by panning around and zooming in on the stars and galaxies.

The world capital of astronomy: Chile

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

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Life

- New Scientist recommends Phoebe Waller-Bridge's documentary Octopus! (paid): 2025 Jun 25

- A new book reveals the deep flaws in our natural history museums (paid): 2025 Jun 25

- Ancient people took wallabies to Indonesian islands in canoes (paid): 2025 Jun 24

- Orcas scrub each other clean with bits of kelp: 2025 Jun 23

LIFE | JUN 25, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

New Scientist recommends Phoebe Waller-Bridge's documentary Octopus!

The books, TV, games and more that New Scientist staff have enjoyed this week

By Bethan Ackerley

Octopus!

Prime

Phoebe Waller-Bridge has worked on some unusual projects since Fleabag, the comedy-drama that made her name and broke many a heart. Octopus!, a two-part documentary on Amazon Prime Video about (you guessed it) octopuses, may just be the oddest one yet.

That exclamation mark is an omen of the whimsy to come – this is an eccentric portrait of one of the most unusual animals to have ever lived. Rather than taking a strictly scientific approach, it is a look at octopuses through the eyes of people who adore them. They have many fans, myself included – who knew I was in a club with comedian Tracy Morgan, who credits the cephalopods for their “vulnerability”?

There are many octopuses featured here that I instantly fell in love with, from femme fatale Samantha, who kills her mate during an erotic encounter, to Inky, who broke out of a New Zealand aquarium and made it to the ocean. This is a fitting tribute to our tentacled friends.

LIFE | JUN 25, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

A new book reveals the deep flaws in our natural history museums

Natural history museums teach us about our world, but they aren’t telling us the whole story, writes curator Jack Ashby in Nature's Memory

By Chris Stokel-Walker

What’s missing? Pondering the displays at the American Museum of Natural History in New York City

Jeffrey Greenberg/Universal Images Group via Getty Images

Nature’s Memory

Jack Ashby (Allen Lane)

Museums are strange things, Jack Ashby, assistant director of the University Museum of Zoology in Cambridge, UK, points out in his new book, Nature’s Memory: Behind the scenes at the world’s natural history museums. They are signifiers of our society and natural records of our ecosystems and habitats, yes. But they are also deeply flawed and significantly skewed.

Museums, especially the natural history ones that Ashby focuses on in his book, were once seen as a giant taxonomy of everything that ever lived – and continues to live – on our planet. From flora to fauna, mammals to insects, the goal of early cataloguers was to document and present everything in our world to help us better understand it.

That was then, and this is now. Reality bites, as Ashby deftly shows in this engaging book, which persuasively casts a critical eye over the imperfections of museums and how they aren’t what we have often thought them to be. For one thing, vast volumes of our natural history aren’t actually on display in these institutions, but are consigned to dimly lit storerooms.

We quickly learn how important the areas behind the velvet ropes and polished glass are: around 70,000 more species of flowering plants are believed to exist in the world than scientists have described, says Ashby, with around half of them probably already sitting in museum back catalogues waiting to be analysed.

His insights into how things work behind the scenes are some of the most arresting points in the book, as he describes how animal skeletons are stripped of their flesh for preservation and how insects are preserved and then pinned to display boards. How taxidermy models are presented and why displayed frogs are rarely real (they shrivel up badly) are two more enlightening passages, as is a section on a premium glass-maker renowned for producing the most realistic recreations of flowers.

But there are even bigger issues at play than those 70,000 missing plants: the exhibits we file past on school trips as we formatively learn about our planet and its populations are biased.

Ashby points to a 2008 case study that found just 29 per cent of mammals and 34 per cent of birds in the average natural history museum are female, vastly understating their contribution to habitats. In part, that is because the male of the species is often more decorative and lends itself better to being displayed. However, it is also because the people who collect and display the items are invariably men – and white, Western men at that, says Ashby.

He is strongest in his rallying cry to change that problem of misrepresentation within museums. Ashby makes a compelling case that we have all been badly educated about our world and nature because of the squeamishness and the proclivities of past generations. Most male mammal skeletons differ from humans in one significant way: the presence of a baculum, or penis bone – not that you would know it from the displays in most museums worldwide, thanks to prudish curators who simply removed the bone from the pelvis.

This book was written before the wilful destruction of scientific institutions in the US, but in the fug of a general anti-expert malaise – and it shows. It is for this reason that it ought to be read. We must consider the consequences of what is left out of museum displays just as much as we do for what is kept in.

As Ashby puts it: “The work taking place in natural history museums has never been more important, and the role they have to play in safeguarding humanity’s future is only just starting to be realised.”

Chris Stokel Walker is a science writer based in Newcastle, UK

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LIFE | JUN 24, 2025, 6:00 AM EDT | VIEW ON NEW SCIENTIST

Ancient people took wallabies to Indonesian islands in canoes

Humans established a wild population of brown forest wallabies in the Raja Ampat Islands thousands of years ago for their meat and fur in one of the earliest known species translocations

By Christa Lesté-Lasserre

Brown forest wallabies spread to several islands thousands of years ago

Mehd Halaouate, Birdingindonesia.com

As early as 12,800 years ago, people captured wild wallabies and transported them in canoes to islands dozens or even hundreds of kilometres away.

Native to Sahul – the prehistoric landmass that later split into Australia and New Guinea – the marsupials probably accompanied human explorers and traders to islands across South-East Asia as sources of food, decorative pelts and eventually bone tools. The imported animals established colonies and thrived there for thousands of years, in one of the world’s oldest known cases of animal translocation, says Dylan Gaffney at the University of Oxford.

“This builds into a global picture where these early people were moving, managing and rearing animals in much more complicated and purposeful ways than we thought – possibly in some ways that early agriculturalists would have,” he says. “They weren’t just surviving in these tropical island environments; they were actively shaping them.”

Scientific work on species translocations has typically focused on European explorers – like their introduction of invasive rabbits into Australia in the 18th and 19th centuries, or the reintroduction of horses to the Americas in the late 1400s and early 1500s.

But in the 1990s, researchers found bones of two kinds of marsupials – the cuscus (Phalanger orientalis breviceps or Phalanger breviceps) and the bandicoot (Echymipera kalubu) – on islands east of New Guinea, and brown forest wallabies (Dorcopsis muelleri) on islands as far west as Halmahera, about 350 kilometres away from the ancient coastline of Sahul.

Based on the age of nearby charcoal and the depth of the remains, those teams estimated that the wallabies arrived about 8000 years ago, and the other animals between 13,000 and 24,000 years ago.

How those animals got to the islands – whether by human transport or on their own – has not been established. To find out, Gaffney and his colleagues investigated a new archaeological site in the Raja Ampat Islands in Indonesia, which lay a few kilometers offshore from northwest Sahul when sea levels were low thousands of years ago.

There, skeletons with ages thousands of years apart suggest that colonies of brown forest wallabies lived and reproduced on the islands for generations before vanishing about 4000 years ago, for reasons yet unclear.

Radiocarbon dating in an inland cave showed people were butchering and cooking wallabies as early as 13,000 years ago – 5000 years earlier than on islands further west – and were still doing so around 4400 years ago.

The team also found several bone tools, probably used for hunting and textile work, including one confirmed by molecular analysis to have been made from a bone of the wallaby family about 4300 years ago.

To address the question of how the animals got there – and to islands farther away – the team used computer modelling, accounting for sea levels and environmental conditions at the time.

The modelling supports the idea that humans transported the animals by canoe, Gaffney says. Without human help, the wallabies would have had to swim across the open ocean for more than 24 hours in powerful currents or cling to vegetation rafts for up to 10 days to reach some of the islands, making their survival highly unlikely. And while it is feasible that the animals could have reached nearby islands by swimming, no one knows whether forest wallabies – modern or ancient – could swim at all.

Canoe trips, by contrast, would have lasted just a few hours to two days depending on the route – probably short enough for captive animals to survive the trip, he says.

The findings highlight just how far back human-driven species movements go – well before European colonial expansion, says Tom Matthews at the University of Birmingham, UK, who wasn’t involved in the study. “We often assume introductions only started in the last 500 years, but this shows humans were reshaping ecosystems thousands of years ago.”

Journal reference:

Journal of Archaeological Science DOI: 10.1016/j.jas.2025.106241

LIFE | JUN 23, 2025, 12:00 PM EDT | VIEW ON NEW SCIENTIST

Orcas scrub each other clean with bits of kelp

Drone footage has captured killer whales breaking off stalks of kelp and rubbing the pieces on other orcas, a rare case of tool use in marine animals

By Sofia Quaglia

Groups of killer whales exhibit strong social behaviour

Shutterstock/Tory Kallman

Orcas off the west coast of North America are grooming each other with kelp, in a rare sighting of marine mammals manufacturing and using tools.

For several years, scientists have been keenly observing 80 endangered killer whales in the segment of the Pacific Ocean between British Columbia and Washington state. To get a bird’s eye view of the whales’ lives, the researchers also tracked them with drones.

While poring over footage from summer 2024, they noticed that the orcas were manoeuvring strands of kelp in odd ways. It was “really weird”, says Rachel John at the Center for Whale Research in Washington state, “but the whales, they do weird things all the time”.

In the footage, the orcas can be spotted breaking off kelp stalks near where they meet the rock bed by grabbing them with their teeth and jerking their heads back and forth. The short, snapped-off segments were roughly equivalent in length to that of the whale’s beak-like face. Over and over again, the orcas appear to consistently target just that specific segment of the algae, not other random parts of kelp.

After breaking off a strand, a whale would then sandwich the kelp between their head and the bodies of other whales in the pod, rubbing and rolling it onto each other’s sides. They take turns cleaning each other with the kelp, sometimes grooming each other for up to 12 minutes.

“What’s cool is that they don’t have any kind of hand-like appendages, and so they’re doing all of this using very deliberate movements of their body,” says John.

Orcas are known to rub themselves against kelp on their own, known as “kelping”. This could be a social variation of that behaviour. “We know that the social bonds in this population are super, super strong, and we know that contact is one way that they reinforce those bonds,” says John.

The behaviour was present across all ages and sexes, though the data suggests the whales that were most closely related and those closer in age were more likely to “kelp” together. Crucially, this may be a form of whale hygiene, says John, as the team found that orcas are more likely to scrub each other with kelp if they are shedding their skin.

It might still be too early to confirm whether this skincare has health benefits, says Olaf Meynecke at Griffith University, Australia. He would like to see the researchers cross-reference the orcas’ skin bacteria with the properties of the kelp to see if they match.

“It totally makes sense to me that they are seeking out anything that the ocean could offer to help them with potential reduction in skin infections,” says Meynecke. He suspects this is a widespread behaviour among other orca populations and whale species.

Journal reference

Current Biology DOI: 10.1016/j.cub.2025.04.021

Earth

- Dramatic Edward Burtynsky image shows stark desert divide: 2025 Jun 25

EARTH | JUN 25, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

Dramatic Edward Burtynsky image shows stark desert divide

This shot by the acclaimed photographer, taken from a helicopter, is part of a new exhibition of his work at New York City's International Center of Photography

By Simon Ings

Edward Burtynsky, courtesy Howard Greenberg Gallery, New York

There is no geophysical logic to the sharp partition in the middle of this picture. A US federal act, the Land Ordinance of 1785, divided North America’s vast western territories into rectilinear townships and sections. So when pumps pull water out of the aquifer beneath Salt River Valley, Arizona, squares of desert like this suburb of Phoenix grow green, settled and busy.

The Indigenous Pima and Maricopa peoples used to farm this land; it was turned into this comfortable conurbation in the 2000s. Valley settlements like this one depend on an increasingly complex and costly water-management system.

Photographer Edward Burtynsky was in a helicopter on his way to the already-desertified Colorado river delta in Mexico in 2011 when he spotted this place. As a student, his first assignment had been to “capture evidence of the activities of man”. He likes to say that, after 40 years of pioneering effort with large-format colour, digital and drone photography, he has more or less delivered. “I was out there early,” he says, “trying to figure it all out, trying to tell the story of our impact on the planet.”

Link to video: https://www.youtube.com/watch?v=A5wVWbiJOb4

This shot and more of Burtynsky’s photos are being exhibited in a solo exhibition, The Great Acceleration, at New York City’s International Center of Photography until 28 September.

Health

- How might society react to babies with two genetic fathers?: 2025 Jun 25

- Mice with two fathers have their own offspring for the first time: 2025 Jun 23

- Nightmares linked to faster biological ageing and early death: 2025 Jun 22

LEADER: HEALTH | JUN 25, 2025, 2:00 PM EDT | VIEW ON NEW SCIENTIST

How might society react to babies with two genetic fathers?

Mice created using genetic material from two sperm cells have gone on to have offspring off their own, but the prospect of one day using the technique in humans has potential to cause controversy

By New Scientist

Drazen_/Getty Images

“All hell will break loose, politically and morally, all over the world.” So said James Watson, the Nobel prize-winning co-discoverer of DNA’s double helix, on the possibility of human in vitro fertilisation in 1974. Four years later, Louise Brown, the first successful IVF baby, was born.

Today, more than 12 million people have been conceived via IVF, and hell seems still to be broadly contained. Few of us would bat an eye at the procedure.

But what of our attitudes to future reproductive technology? That question is raised by the birth of fertile mice with two genetic fathers. Such feats have been attempted before, creating both motherless and fatherless mice, but this latest technique stands apart because it doesn’t involve genetic modification. In principle, that makes it suitable for use in humans.

There are many technical reasons why this won’t happen soon, from the low success rate to the large number of human eggs, stripped of their DNA, that would be required. Despite that, we should start thinking about the social hurdles.

For some people, the thought of a child with two genetic fathers will never be acceptable, just as there are still those who decry gay couples adopting a family. Such minds will be difficult, if not impossible, to change.

As with IVF, what was once front-page news could become run of the mill

But we can expect a broader group of people to have, if not strict moral objections to the idea, a general unease. The first children born in this way, if any are, will, in a way, be unlike any humans that have ever existed. While IVF children are conceived via a process our ancestors could never imagine, they still continue a genetic lineage of every person having one male progenitor and one female.

Does this matter? Quite possibly not – as with IVF, what was once front-page news could become run of the mill. But in an era when the US is curtailing reproductive and transgender rights, having an open discussion about the technology without prejudice will be the bigger challenge. It is perhaps fortunate that these questions don’t have to be settled any time soon.

HEALTH | JUN 23, 2025, 4:00 PM EDT | VIEW ON NEW SCIENTIST

Mice with two fathers have their own offspring for the first time

We're a step closer to two men being able to have genetic children of their own after the creation of fertile mice by putting two sperm cells in an empty egg

By Michael Le Page

Adult male mice that have two fathers and went on to have offspring of their own

Yanchang Wei

For the first time, mice with two fathers have gone on to have offspring of their own – marking a significant step towards enabling two men to have children to whom they are both genetically related. However, there is still a long way to go before this could be attempted in people.

Yanchang Wei at Shanghai Jiao Tong University in China achieved the feat by putting two sperm cells together in an egg whose nucleus had been removed. The team then used a method called epigenome editing to reprogram seven sites in the sperm DNA, which was needed to allow the embryo to develop.

Of the 259 of these embryos that were transferred to female mice, just two offspring – both male – survived and grew to adulthood, making the success rate very low. Both then fathered offspring – which appeared normal in terms of size, weight and appearance – after mating with females.

Creating mice with two fathers has proved to be much harder than creating mice with two mothers. The birth of the first fertile mouse with two mothers, Kaguya, was reported in 2004.

Kaguya had to be genetically modified, but in 2022, Wei and his colleagues were able to create similarly fatherless mice using only epigenome editing, which doesn’t alter the DNA sequence. This same method was used to make the motherless mice.

The reason it is such a significant feat to create mammals with two fathers or two mothers is due to a phenomenon called imprinting, which is related to the fact that most animals have two sets of chromosomes, one inherited from the mother and one from the father.

During the formation of eggs and sperm, chemical labels are added to these chromosomes that program some genes to be active and others to be inactive. These changes are called “epigenetic” because they don’t change the underlying DNA sequence, but the labels can still be passed on when cells divide, meaning their effects can last a lifetime.

Crucially, epigenetic programming in mothers is different from that in fathers, with some genes that are labelled as “on” in sperm being labelled as “off” in eggs, and vice versa.

This means that if an egg has two sets of maternal chromosomes, or two sets of paternal ones, it cannot develop normally. A gene that should be active in one chromosome of a pair may be turned off in both, or both copies of a gene may be active when only one should be, resulting in an “overdose” of that gene.

In Kaguya’s case, researchers got around this by deleting part of a gene to make overall gene activity more normal. But creating mice with two fathers requires many more changes.

Earlier this year, a separate team in China got a few mice with two fathers to grow to adulthood after making 20 genetic modifications to normalise their gene activity, but these mice weren’t fully healthy or fertile.

While correcting gene activity via genetic modification is useful for studying imprinting in lab animals, it would be unacceptable in people, not least because the effects of the genetic changes aren’t fully understood.

For their epigenetic approach, Wei and his team used modified forms of the CRISPR proteins that are usually used for gene editing. Just like standard CRISPR proteins, these can be made to seek out specific sites on genomes. But when these sequences are found, the modified proteins add or remove epigenetic labels rather than altering DNA.

The study is a major step forward, says Helen O’Neill at University College London. “It confirms that genomic imprinting is the main barrier to uniparental reproduction in mammals and shows it can be overcome.”

Because it doesn’t involve genetic modification, the epigenome-editing approach could, in principle, be used to allow same-sex couples to have genetic children of their own. However, the success rate would need to be much higher before the technique could be considered for use in people. “While this research on generating offspring from same-sex parents is promising, it is unthinkable to translate it to humans due to the large number of eggs required, the high number of surrogate women needed and the low success rate,” says Christophe Galichet at the Sainsbury Wellcome Centre in the UK.

There are several reasons why the success rate was so low. For starters, combining two sperm cells means a quarter of the embryos had two Y chromosomes and wouldn’t have developed far. Also, the epigenome editing only worked at all seven sites in a small proportion of the embryos, and it might have had off-target effects in some cases.

The success rate and health of the animals could probably be improved by altering more than seven sites. Another issue is that in people a slightly different set of sites might need altering.

If human babies with two fathers are ever created in this way, they would technically be three-parent babies because the mitochondria in their cells, which contain a tiny amount of DNA, would come from the egg donor.

In 2023, a team in Japan announced the birth of mouse pups with two fathers using a third technique that involves turning mouse stem cells into eggs. However, it isn’t clear if any pups survived to adulthood, and so far no one has managed to turn human stem cells into eggs.

Journal reference:

PNAS DOI: 10.1073/pnas.2425307122

HEALTH | JUN 22, 2025, 7:01 PM EDT | VIEW ON NEW SCIENTIST

Nightmares linked to faster biological ageing and early death

Scary dreams disrupt our sleep and elevate our levels of the stress hormone cortisol, which may have serious consequences for our health over time

By Chris Simms

There are things we can do to prevent nightmares, such as not watching scary movies

Andrii Lysenko/Getty Images

Having nightmares on a weekly basis seems to accelerate ageing – and could even triple the risk of early death.

“People who have more frequent nightmares age faster and die earlier,” says Abidemi Otaiku at Imperial College London.

Along with his colleagues, Otaiku analysed more than 183,000 adults, aged 26 to 86, who had taken part in several studies. At the start, the adults self-reported how often they had nightmares, and were then tracked for as little as 1.5 years to as long as 19 years.

The researchers found that those who reported having nightmares on a weekly basis were more than three times as likely to die before they turned 70 than those who said they never or rarely had nightmares.

There is a clear association, says Otaiku, whose team also found nightmare frequency to be a stronger predictor of premature death than smoking, obesity, poor diet or lack of physical activity. He will present the results at the European Academy of Neurology Congress 2025 in Helsinki, Finland, on 23 June.

The team also assessed the participants’ biological age by measuring the length of their telomeres, which are small DNA sequences at the end of chromosomes that shorten each time a cell divides, with shorter ones being linked to premature ageing. This part of the study also included data from about 2400 children, aged between 8 and 10, whose nightmare frequency was reported by their parents. The adults had their biological age additionally assessed via molecular markers known as epigenetic clocks.

Otaiku says the team found a consistent association between frequent nightmares and accelerated ageing across all ages, sexes and ethnicities. “Even in childhood, people who have more frequent nightmares have short telomeres, indicating faster cellular ageing,” he says. Among the adults, the faster biological ageing accounted for about 40 per cent of their heightened mortality risk.

As for why this association occurs, Otaiku says it could stem from two factors. The first is that nightmares cause prolonged high levels of the stress hormone cortisol, which has been linked to faster cellular ageing. “Nightmares often wake us with our hearts pounding, in a stress reaction more intense than anything we experience when awake,” he says.

The second factor is disrupted sleep, which upsets the body’s overnight cellular repair processes. Sleep disruption has been linked to increases in the risk of various medical conditions, including heart disease.

If people want to avoid regular nightmares, there are often easy ways to do it, says Otaiku, including not watching scary movies and seeking treatment for mental health conditions like anxiety.

“It’s an interesting finding and there is lots of biological plausibility,” says Guy Leschziner at Guy’s and St Thomas’ NHS Foundation Trust. However, he says, more research is needed to establish a causal link. Nightmares can be associated with a range of medical conditions and medications that people could have as they get older, which could be confounding the results, he says.

Table of Contents

New Scientist: 2025 Jun 27

Features

Why are the physical constants of the universe so perfect for life? (paid): 2025 Jun 23

How metaphysics probes hidden assumptions to make sense of reality (paid): 2025 Jun 23

Why geoengineering is no longer a complete taboo for scientists (paid): 2025 Jun 23

Why physicists think geometry is the path to a theory of everything (paid): 2025 Jun 23

The deep lessons quasiparticles teach us about the nature of reality (paid): 2025 Jun 23

Ancient humans only evolved language once, but why? (paid): 2025 Jun 23

News

X-ray boosting fabric could make mammograms less painful: 2025 Jun 27

Mathematicians create a tetrahedron that always lands on the same side (paid): 2025 Jun 27

The bold plan to save a vital ocean current with giant parachutes (paid): 2025 Jun 27

These rocks are probably the last remains of Earth's early crust: 2025 Jun 26

Mystery fireball spotted plummeting to Earth over the US: 2025 Jun 26

Ash trees are rapidly evolving some resistance to ash dieback disease: 2025 Jun 26

Deep sleep seems to lead to more eureka moments (paid): 2025 Jun 26

Nearly a third of Tuvaluans have applied for climate migration visa (paid): 2025 Jun 26

Extreme winter weather isn’t down to a wavier jet stream: 2025 Jun 26

Independent estimate of Gaza deaths is higher than official figures (paid): 2025 Jun 25

Ancient mammoth-tusk boomerang is twice as old as we thought: 2025 Jun 25

Gastric bypass surgery may cut the risk of bowel cancer: 2025 Jun 25

Cancer cells steal mitochondria from nerve cells to fuel their spread (paid): 2025 Jun 25

Heart attacks are no longer the leading cause of death in the US: 2025 Jun 25

Generation Alpha's coded language makes online bullying hard to detect (paid): 2025 Jun 25

Small and speedy dinosaur recognised as a new species: 2025 Jun 25

Enigmatic lizards somehow survived near Chicxulub asteroid impact: 2025 Jun 25

Women's pelvises are shrinking – how is that changing childbirth? (paid): 2025 Jun 24

Leonardo da Vinci's 'helicopter' design could make drones quieter (paid): 2025 Jun 24

Earth is more sensitive to greenhouse gases than we thought (paid): 2025 Jun 24

Technology

Forget the Terminators, our robot future may be squishy and fun (paid): 2025 Jun 25

Why is it seemingly impossible to stop phone thieves?: 2025 Jun 23

Space

Read an extract from Adam Roberts’s far future-set Lake of Darkness: 2025 Jun 27

Weird line of galaxies may have been created by a cosmic bullet (paid): 2025 Jun 24

Vera Rubin Observatory has already found thousands of new asteroids: 2025 Jun 23

Stellar flares may hamper search for life in promising star system (paid): 2025 Jun 23

Stunning first images show the power of the Vera C. Rubin Observatory: 2025 Jun 23

Life

New Scientist recommends Phoebe Waller-Bridge's documentary Octopus! (paid): 2025 Jun 25

A new book reveals the deep flaws in our natural history museums (paid): 2025 Jun 25

Ancient people took wallabies to Indonesian islands in canoes (paid): 2025 Jun 24

Orcas scrub each other clean with bits of kelp: 2025 Jun 23

Earth

Dramatic Edward Burtynsky image shows stark desert divide: 2025 Jun 25

Health

How might society react to babies with two genetic fathers?: 2025 Jun 25

Mice with two fathers have their own offspring for the first time: 2025 Jun 23

Nightmares linked to faster biological ageing and early death: 2025 Jun 22