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Earth is no longer at risk of a direct collision with the asteroid 2024 YR4, but an impact on the moon in 2032 could send debris hurtling towards our planet that could take out orbiting satellites

Asteroid 2024 YR4 could result in the largest impact on the moon for the past 5000 yearsMARK GARLICK/SCIENCE PHOTO LIBRARY/Getty Images

Asteroid 2024 YR4 could result in the largest impact on the moon for the past 5000 years

MARK GARLICK/SCIENCE PHOTO LIBRARY/Getty Images

The asteroid 2024 YR4, which was once thought to be on acollision course with Earth, may still pose a threat to the planet. There is still a chance the space rock could smash into the moon, and the resulting explosion could shower Earth with a cloud of satellite-destroying shrapnel.

Astronomers have been tracking the building-sized asteroid since it was discovered in December 2024, when initial predictions of its path raised the possibility of a collision with Earth in 2032. Such a collision would have released enough explosive power to destroy a city, but, thankfully, follow-up observations showed that 2024 YR4 willalmost certainly miss our planet.

Read moreThe sun is killing off SpaceX's Starlink satellites

The sun is killing off SpaceX's Starlink satellites

The chance of acollision with the moon, however, has slowly been increasing, and now stands at 4.3 per cent based on the last observations taken before the asteroid flew out of view of our telescopes until 2028. And according toPaul Wiegertat the University of Western Ontario in Canada and his colleagues, such a collision could still cause significant damage to Earth’s satellites.

“We were a little bit surprised at the possibility of there being a substantial amount of material at the Earth,” says Wiegert. “Intuitively, the Earth is actually quite a small target when seen from the moon, and so your intuition is that not very much material would actually hit the Earth, but it turns out that the Earth’s gravity can focus that material under certain conditions.”

Wiegert and his team calculated that 2024 YR4 could create a kilometre-wide crater on the moon – the largest lunar impact for at least the past 5000 years, though relatively small compared with a typical crater. An impact of this size would eject a cloud of debris into space, and by simulating its potential behaviour 10,000 times, the team found that this could cause Earth’s satellites to experience a level of collisions equivalent to what we would expect to see in years or even decades, but occurring in just a few days.

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While these collisions might not be enough to take out entire satellites, they could cause anomalous readings due to electrical flashes, though it is hard to model exactly how damaging it will be for satellites, says Wiegert.

If we are unlucky, the effect of debris particles could be particularly bad, saysMark Burchellat the University of Kent, UK. “If they were to hit a bit of a spacecraft that was a coolant pipe, or a sensor on the spacecraft exposed to space, or an antenna, then suddenly you get a loss of that particular functionality,” he says. “You can’t go and fix a satellite. A minor problem is actually a serious problem.”

Read moreAstronomers have spotted the largest known object in the universe

Astronomers have spotted the largest known object in the universe

Wiegert says the results should make the world’s space agencies think about deflecting asteroids that are going to hit the moon, as well as Earth. A spokesperson from NASA’s Planetary Defense Coordination Office says its job is to “identify near-Earth objects (NEOs) that could pose an impact hazard to the Earth, so planetary defense is not solely confined to near-Earth space”, but that it would be “premature to speculate on potential response options” to 2024 YR4 hitting the moon.

Depending on how things go, we may need to act quickly. When 2024 YR4 flies back into view of Earth’s telescopes in 2028, we should be able to swiftly refine our knowledge of its exact orbital path, says Wiegert. If the odds of it hitting the moon go up, that will give us a four-year window to decide whether we need to act, he says.

Reference:arXivDOI: 10.48550/arXiv.2506.11217

arXivDOI: 10.48550/arXiv.2506.11217

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Even if agricultural practices adapt in response to higher temperatures, five of the world's six main staple crops will suffer severe losses due to climate change

Climate change will reduce the supply of most staple crops, including cornJon Rehg/Shutterstock

Climate change will reduce the supply of most staple crops, including corn

Rising global temperatures are likely to cause deep losses to the world’s most important crops – despite farmers’ best efforts to adapt. A global analysis of crop yields suggests that, by the end of the century, each degree Celsius of warming will reduce the food available per person by about 121 kilocalories per day.

Under a 3°C warming scenario – roughly our current trajectory – “that works out to giving up breakfast for everyone”, saysAndrew Hultgrenat the University of Illinois Urbana-Champaign.

Read moreFarms can install vertical solar panels without reducing crop yields

Farms can install vertical solar panels without reducing crop yields

Hultgren and his colleagues collected data on the yields of the world’s six main staple crops, accounting for more than two-thirds of global calories. “It’s one of the largest datasets now available of high-resolution crop yields,” he says. They also collected information on local weather patterns from 54 countries.

The researchers then used this information to project how the different crops would respond to a changing climate – and how farmers would adjust as well. “We mined that data for information about how farmers have reacted to weather shocks historically,” says Hultgren. This allowed the researchers to estimate how different agricultural adaptations, such as changing which crop varieties are grown, boosting irrigation or using more fertiliser, would mitigate crop losses.

For all crops except rice, which grows better when nights are warmer, they found that higher temperatures will lead to steep losses. For instance, global corn yields are projected to fall by about 12 or 28 per cent by the end of the century – depending on whether greenhouse gas emissions are moderate or very high respectively – relative to what they would be without global warming.

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These numbers account for how farmers would adapt to higher temperatures, as well as the impact of potentially helpful climate-change effects, such as crops being fertilised by increased levels of carbon dioxide. Both make a big difference – for example, without adaptation, crop losses would be about a third higher at the end of the century under a high-warming scenario – but they don’t offset the majority of the losses. “In a high-warming future, you start to wonder if the [US] corn belt is going to be the corn belt,” says Hultgren.

Wolfram Schlenkerat Harvard University says the conclusion that farming adaptations are unlikely to make up for crop losses due to climate change tallies with previous findings focused on specific regions. “The huge contribution of their study is they didn’t just focus on one country, but they compile this data from countries around the world,” he says.

That global view reveals some interesting patterns. For instance, the researchers found that the largest projected crop losses don’t occur in low-income countries, but in the relatively wealthy breadbaskets of the world, such as the US Midwest and Europe. “They’re not better adapted to it than poorer countries,” says Schlenker.

Michael Robertsat the University of Hawai’i at Manoa says the findings are in line with results from smaller-scale studies. But he points out that huge uncertainties remain, including the extent of future climate change and how the extraordinarily complex global food system will respond.

“The scary thing is, we just don’t know,” says Roberts. “There’s incredible uncertainty, and most of that is on the downside. Anything is possible, from no losses to devastating losses that would cause mass starvation. That should be humbling for people.”

Journal referenceNatureDOI: 10.1038/s41586-025-09085-w

NatureDOI: 10.1038/s41586-025-09085-w

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Assigning certain sizes, shapes and positions of bubbles to characters within Morse and binary codes means messages could be stored in ice

Ice could offer a way of storing messages long-term in cold environmentsAnton Petrus/Getty Images

Ice could offer a way of storing messages long-term in cold environments

Information could potentially be stored inicefor millennia, simply by making subtle changes to the shape and position of internal bubbles, which can then be converted into binary or Morse codes.

Mengjie Songat the Beijing Institute of Technology in China and his team were studying the formation of ice when they realised they could influence the size and shape of the bubbles that formed within. For instance, when freezing layers of water between plastic sheets, they found that changing the freezing rate created either egg-shaped or needle-shaped bubble layers.

Read moreGeoengineering could save the ice sheets – but only if we start soon

Geoengineering could save the ice sheets – but only if we start soon

The researchers then assigned bubble sizes, shapes and positions to characters within Morse and binary codes. Controlling the freezing rate of thewaterbetween the plastic sheets then created ice that spelled out a message via internal bubbles.

When they converted a photo of this ice into grey scale, the areas that appeared white represented regions of ice with bubbles, while black areas were bubble-free. From this, a computer could detect the size and position of the bubbles and decode the message.

Only a few sentences of information could be stored in a standard ice cube using available technology, but it is possible that information could also be stored by manipulating bubbles inside materials such as plastics, says Song.

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He says the research has many applications, besides just the “novelty of being able to read a message encoded in an ice cube in a drink”. “The advantage of this study is the capacity for long duration storage of information in a cold environment, such as in the north or south pole,” says Song.

Understanding bubbles better means they could one day be made to contain ozone for food preservation or hold slow-release drugs, he says. He is particularly interested in how bubbles could help prevent ice forming on aircraft wings and learning how they will behave in lunar environments.

ButQiang Tangat the University of Sydney, Australia, is less convinced by the study’s real-world potential, arguing that important information can be stored for a long time on hard discs or paper, which are easily backed up.

“It’s a new way of representing a message and storing it in a new place, but from a cryptography or security perspective, I don’t think it will be useful at all unless a polar bear may want to tell someone something,” he says.

Journal reference:Cell Reports Physical ScienceDOI: 10.1016/j.xcrp.2025.102622

Cell Reports Physical ScienceDOI: 10.1016/j.xcrp.2025.102622

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Ticks are spreading globally and bringing familiar conditions such as Lyme disease with them, as well as totally new ones. Now research is revealing how to prevent and treat the diseases they carry

Ticks carry more zoonotic pathogens than any other known vectorSergey Aleshin/Getty Images

Ticks carry more zoonotic pathogens than any other known vector

Tucked away in a ground-floor lab in Richmond, Virginia, is a bank of industrial freezers containing thousands of transparent, thumb-sized plastic tubes. Each is filled with a clear, yellowish fluid – blood serum taken from opossums, raccoons, black bears, coyotes, vultures and many other animals.

These vials, the world’s largest collection of blood serum from wildlife, are the life’s work of Virginia Commonwealth University molecular biologistRichard Marconi. Almost every sample here is infected with some kind of tick-borne pathogen – mostly the bacterium that causesLyme disease, one of the most widespread tick-borne diseases, but others as well.

Read moreHow to tell if your immune system is weak or strong

How to tell if your immune system is weak or strong

That means, says Marconi, that most wild animals in North America have been infected. Those animals represent a vast and growing reservoir of viral, parasitic and bacterial pathogens for ticks to pass on to other animals – including humans. In fact, ticks carrymore human-infecting pathogens than any other disease-carrying organism.

Right now, tick populations are exploding, their ranges are expanding and they are bringing those pathogens with them. “It’s not just a problem here in the United States. This is occurring across the northern hemisphere,” says Marconi.

We can’t stop ticks from spreading – we’ve tried. That leaves mitigating the damage they do. Marconi’s lab is pioneering a slew of novel protein-editing techniques to generate vaccines against Lyme and other tick-borne illnesses; others are working on vaccines not against these diseases, but against the ticks themselves.

These are promising directions – the only question is: will they be enough?

Around 900 tick species call this planet home. Every one of them feeds on blood.Since branching off from their spider ancestors hundreds of millions of years ago, ticks have evolved a three-pronged mouthpart designed for feeding on vertebrates. Sharp, serrated edges saw through the outer layer of the host’s skin, while a tiny barb anchors the tick to its meal. A thin groove on the underside of the mouthpart’s centre blade funnels blood directly into the tick’s midgut. To prevent their hosts from reacting to their presence, ticks have specialised proteins in their saliva that suppress pain and allergic reactions, while other proteins inhibit blood clotting, allowing ticks to dine at a more leisurely pace. Some tick species feed only on blood from a specific animal host, but others, such asIxodes scapularis, better known as the deer tick or black-legged tick, are far less choosy.

Ticks have been here a lot longer than we have

Ticks have been here a lot longer than we have

The fact that ticks can remain on a host for several days undetected means that where their meals go, they go. And as the planet warms, the number of places ticks can thrive is growing. The highest latitude at which they can live is shifting, saysNick Ogden, an ecologist and epidemiologist at the Public Health Agency of Canada. Ogden and others havedocumented black-legged ticksas far north as Yukon, above latitude 60° north, brought bymigrating songbirds.

“These birds create a conveyor belt for ticks. When the climate becomes suitable, they can set up a population,” says Ogden. Rising temperatures and increased humidity also mean that ticks, though still mainly a spring and summer problem, can be active for more of the year.

Migrating songbirds, like this wood thrush, can be vehicles for ticksMichael Greenfelder/Alamy

Migrating songbirds, like this wood thrush, can be vehicles for ticks

The implications of this tick boom are unfortunately clear: more ticks in more places means more disease. Ticks are superb vehicles for pathogenic hitchhikers, and there are a lot of pathogens looking for rides. For instance, Marconi and his lab looked atblood samples of 128 coyotesfrom Pennsylvania and found that 64.8 per cent tested positive for the Lyme bacterium and 72.7 per cent for the bacterium that causes anaplasmosis, an infection that leads to flu-like symptoms in humans. Ticks pick up these pathogens when they feed, transferring them to their next host through their saliva or faeces (see “How to avoid ticks – and what to do if you can’t”, below).

“As that tick vector expands its geographical range, all of those diseases are following along,” saysHeidi Goethert, a molecular epidemiologist at Tufts University in Massachusetts. In the past 20 years, the annual number of cases of tick-borne diseases in the UShas more than doubled. Europe has seena steady climb in Lyme disease infections, while cases of tick-borne encephalitis, a viral infection that can cause long-term neurological symptoms, have risen byalmost 400 per cent in the past 30 yearsasticks’ ranges expand north. Human encroachment on wildlife habitats is also increasingly putting people in the way of ticks and their diseases – cases of deadly Rocky Mountain spotted fever have become an“urban epidemic”in Brazilian and Mexican cities, driven by proximity to capybaras and free-roaming dogs.

Inside the new therapies promising to finally beat autoimmune diseaseType 1 diabetes, IBD, multiple sclerosis, rheumatoid arthritis, coeliac disease and lupus are all caused by the body attacking itself. But new therapies that reset the immune system could offer lasting help

Inside the new therapies promising to finally beat autoimmune disease

Type 1 diabetes, IBD, multiple sclerosis, rheumatoid arthritis, coeliac disease and lupus are all caused by the body attacking itself. But new therapies that reset the immune system could offer lasting help

Ticks are a source of new illnesses as well. In the early 2000s, people in the south-eastern US started turning up in doctors’ offices with classic symptoms of allergic reaction triggered by a previously unheard-of allergen: red meat. In 2009, the lone star tick was confirmed as the source of thisallergy to alpha-gal, a sugar found in mammalian meat. Since then, more than 110,000 cases ofalpha-gal syndromehave been identified in the US alone. The lone star tick also transmits the sometimes fatalHeartland virus, first documented in 2009, while China has identified33 emerging tick-borne diseases in the past several decades, includingWetland virusin 2019.

Part of what makes managing the spread of tick-borne disease difficult is that our understanding of tick ecology is incomplete. For example, Martha’s Vineyard, an island off the coast of Massachusetts, has among the highest per capita rates of Lyme disease in the US. White-footed mice were thought to be the ticks’ likeliest pathogen reservoirs. However, efforts to reduce Lyme on the island by targeting mice – coating them withtick-killing pesticides, say – proved inconsistently effective. Trying to figure out why, Goethert and her team spent six years examining what the ticks actually ate, analysing them for tiny fragments of DNA from their last meal. They found that ticks on Martha’s Vineyardpreferred shrews to mice– meaning that targeting mice wouldn’t work.

“[Ticks] can transmit lots of different pathogens between lots of different animal types. It’s a very complex ecology,” saysLucy Gilbert, an ecologist at the University of Glasgow in the UK.

With attempts to manage ticks through their animal hosts proving unsuccessful, researchers like Marconi are instead trying to tackle the diseases they carry.

Lyme disease, transmitted by several species of tick, was first observed in a handful of children in Connecticut in the 1970s. It is now one of the most widespread tick-borne diseases in the world: a 2022 study estimates that15 percent of the world’s population has been infectedwithBorreliella(formerly known asBorrelia)burgdorferi, the corkscrew-shaped spirochaete bacteria that causes it.

“These bacteria have this really remarkable structure,” says Marconi, who has developed grudging respect forB. burgdorferiin his 30 years of studying it. “When the tick feeds, spirochaetes literally will drill their way through tissue and spread through the body.”

The deer tick is one of the primary transmitters of the bacterium that causes Lyme diseaseShutterstock/KPixMining

The deer tick is one of the primary transmitters of the bacterium that causes Lyme disease

Caught early, Lyme, which often presents with flu-like symptoms and a characteristic bullseye rash, is treatable with antibiotics. However,diagnosing infections can be challenging. Lyme symptoms overlap with those of other illnesses, the rash can be difficult to spot on darker skin and doesn’t always appear, blood tests often give false negatives and – say Marconi and others – doctors don’t always consider Lyme.

“These infections are underappreciated, underdiagnosed and they’re spreading all over the country,” saysIsaac Chiu, a neurobiologist who studies Lyme at Harvard Medical School. Ifleft untreated, Lyme can cause a host of neurological symptoms, including facial paralysis, inflammation in the brain and spinal cord, and pain in the joints and muscles. More frustrating, symptoms of infection persist in some people even after a full course of antibiotics.

That’s becauseB. burgdorferiis tricky. While lurking in a tick’s gut, the bacterium covers itself with a protein called outer surface protein A or OspA. But as soon as the tick gets a taste of mammalian blood,B. burgdorferiswitches out OspA for OspC – adapting to its environment, just as we would put on a winter coat on a cold day, says Marconi – and begins its migration to the tick’s salivary glands and on to its new home. Once there, the OspC covering helps it evade the host’s immune system. “It’s a cat-and-mouse game that continues and continues, and it allows the bacterium to remain and persist in the host,” says bacteriologistTroy Bankheadat Washington State University.

Lyme disease treated with antibiotic that doesn't harm gut microbiomeMice overcame a Lyme disease infection after being given an antibiotic that is often used for pneumonia, and its effect on their gut microbiomes was negligible

Lyme disease treated with antibiotic that doesn't harm gut microbiome

Mice overcame a Lyme disease infection after being given an antibiotic that is often used for pneumonia, and its effect on their gut microbiomes was negligible

That makesB. burgdorferia difficult vaccine target – although this wasn’t what defeated the first Lyme vaccine. In 1998, GlaxoSmithKline brought a vaccine to market that targeted the OspA protein, but although it was effective, it required boosters as much as every year. That was a hard sell even in areas with high rates of Lyme disease, and it was pulled in 2002.

Marconi believed that targeting the OspC protein would offer broader protection. To do that, however, his team needed to create something completely new. OspC proteins come in 21 different strains, which is why some people contract Lyme disease multiple times. “The Lyme bacteria that might be carried by one tick can differ quite a bit from one that’s carried by another tick,” says Marconi. “We had to come up with a way to make a vaccine candidate that could elicit antibodies against all the strains.”

Using a new technique that he and his lab dubbed “chimeritope technology”, they stitched together small snippets of different OspC protein antigens that provoked an immune response. This super protein proved effective enough fora vaccine for dogsthat wasapproved by the US Food and Drug Administration in 2016. A human vaccine is on its way – Marconi’s lab is currently working with the National Institutes of Health to get it into human trials and then on to market in the next several years.

Ticks tend to be found in tall grass and vegetationMarcin Rogozinski/Alamy

Ticks tend to be found in tall grass and vegetation

This isn’t the only Lyme vaccine in the works – with rates of Lyme skyrocketing since 2002, the market has become much more appealing to pharmaceutical companies. Pharmaceutical companies Pfizer and Valneva, working together, are completing the final stage of trials of a second-generation OspA vaccine that generates immunity against the six most common strains ofB. burgdorferiin the US and Europe. But Marconi hopes that chimeritope technology will offer a blueprint for managing whatever the next big tick-borne disease will be in North America, as well as a method for combining vaccines to offer protection against multiple tick-borne pathogens at once.

“What’s really exciting to us about it is that we can apply it to any pathogen,” he says, noting that his team is currently working on vaccines for anaplasmosis, cases of whichincreased 16-fold in the US between 2000 and 2022, and the potentially deadly tick-borne parasiteBabesia. “The sky’s the limit on where we can go with it.”

Marconi’s technology might be able to generate vaccines against multiple pathogens and even combine them into a single, multi-use vaccine. But what if we could generate immunity to ticks themselves – and therefore to every pathogen they carry?

It isn’t impossible – some animals naturally develop immunity against ticks after repeated infections. For example, the immune systems of some cattle create antibodies against proteins and other biomolecules carried by the cattle tick. As the tick feeds, these antibodies go straight to the parasite’s midgut, damaging cells and forcing the tick to fall off before it can transmit disease. After scientistsidentified one of these antibody-generating molecules in the 1980s, anti-tick vaccines for cattle soon appeared on the market. Though imperfect and not universally adopted, the vaccines reliably generated an immune response in cattle and have worked to keep a serious problem from getting worse. Inspired, some scientists are looking to do the same against species of ticks that tend to pose the most problems for humans.

Read moreDogs pollute water with pesticides even weeks after flea treatment

Dogs pollute water with pesticides even weeks after flea treatment

“If this works, it can reduce or prevent multiple tick-borne pathogens – an individual vaccine, you usually can only prevent the one pathogen,” saysYingjun Cui, an infectious diseases researcher at Yale University School of Medicine working on such avaccine against Lyme-carrying deer ticks.

The anti-tick vaccines currently in the works would incapacitate the main weapon in the tick’s arsenal – its ability to feed off a host undetected. In 2021, Cui and his colleagues showed that immunising guinea pigs with a protein secreted in tick saliva during feeding prompteda histamine response in the animals: the site of the bite swelled, interrupting the ticks’ feeding. Cui’s lab has sinceidentified other candidatesfor future vaccines. In addition to the swelling, the irritation is a signal to the host to remove the tick before it can transmit disease – a virus can hop from tick to host in about an hour, but bacteria can take up to 48 hours of feeding to make the leap.

Why antibiotic resistance could make the last pandemic look minorPeople don't realise just how bad our antibiotic resistance problem is, says Jeanne Marrazzo, the top infectious disease specialist in the US

Why antibiotic resistance could make the last pandemic look minor

People don't realise just how bad our antibiotic resistance problem is, says Jeanne Marrazzo, the top infectious disease specialist in the US

“But it’s still not perfect for humans,” says Cui, not least because it is unlikely anyone would want a vaccine that worked in part by giving them an unpleasant reaction to the tick’s bite. Still, his lab isn’t the only one working on an anti-tick vaccine – researchers at the University of Amsterdam are currently working with human volunteers to see ifpeople could generate an immune response after repeated exposure to tick bites.

Marconi is intrigued by the prospect of an anti-tick vaccine, but notes: “We’re willing to tolerate side effects much more in cattle than we probably will be in humans.” For his part, he’s pinning his hope on more traditional vaccines.

“Ticks have been here a lot longer than we have. I think we’re smarter than them, but they’ve learned some tricks that we haven’t been able to quite figure out,” he says. Still, he retains some optimism: “We have our best shot at managing the incidence of disease in humans and in companion animals… It’s a challenge – but I’m not despairing.”

How to avoid ticks – and what to do if you can’tThe best way to avoid a tick-borne disease is to not get bitten at all. Ticks lurk in tall grass or vegetation, waiting for passersby. You can prevent them from latching onto your skin by wearing long trousers, tucked into socks, and long sleeves.Check your body, and those of your children and pets. Ticks are often found on the head, the underarms, groin and along the waist and in the belly button, but check everywhere.If you do find a tick, use tweezers to grasp it as close to the skin as you can and gently pull up. Try not to twist or crush the tick, as the mouthparts could break off in the skin and cause infection. Dispose of the tick and clean the area with an antiseptic.Wash clothing or animal bedding on hot – ticks can survive the washing machine, butnot water above 54°C (129°F).

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Bogong moths are the first invertebrates known to navigate using the night sky during annual migrations to highland caves

Bogong moths migrate to cool caves in the summerDr. Ajay Narendra/Macquarie University, Australia

Bogong moths migrate to cool caves in the summer

Dr. Ajay Narendra/Macquarie University, Australia

An Australian moth that migrates over 1000 kilometres to seek respite from summer heat is the first known invertebrate to use the stars as a compass on long journeys.

Every spring, billions of bogong moths (Agrotis infusa) travel from various parts of southern Australia to cool caves in the Australian Alps after spending the winter as caterpillars feeding on vegetation. Once in the caves, they have a long period of inactivity, called aestivation, before returning to their breeding grounds.

Read moreThe extraordinary ways species control their own evolutionary fate

The extraordinary ways species control their own evolutionary fate

It has long been a mystery exactly how these moths, whose numbers have been collapsing in recent years, navigate so far to these high country caves, saysAndrea Addenat the Francis Crick Institute in London.

Previous studieshave shown that they are able to use Earth’s electromagnetic field, but only in combination with landmarks they can see. Adden and her colleagues wanted to find out what other cues the moths may be using to navigate.

“If you go to the Australian bush, where these moths live, and look around at night, one of the most striking visual landmarks is the Milky Way,” she says. “We know that daytime migratory insects use the sun, so testing the starry sky seemed an obvious thing to try.”

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To do so, the team caught moths during their migration using light traps and took them to a lab. There, the insects were placed in a Perspex arena and an image of the night sky was projected onto a screen above them. The moths were tethered inside the arena, but could pick a flight direction based on the sky image. The researchers used a device called a Helmholtz coil to essentially cancel out Earth’s magnetic field.

The tests showed that the moths use a stellar compass, says team memberEric Warrantat Lund University, Sweden. “When tethered moths were placed under highly realistic local starry night skies, they flew in their inherited migratory direction,” he says. “They did this solely with the help of these stars – all other visual cues, as well as the Earth’s magnetic field, were absent.”

Caption: Aestivating moths in an alpine cave in the summer (there are around 17,000 moths/m2 of cave wall and millions in each cave)Copyright: Eric WarrantEric Warrant

Caption: Aestivating moths in an alpine cave in the summer (there are around 17,000 moths/m2 of cave wall and millions in each cave)Copyright: Eric Warrant

When the team turned the starry sky by 180 degrees, moths flew in the opposite direction, and when they randomly redistributed the natural stars across the image they were completely disoriented.

In a second experiment, the moths were fixed in place with a very thin electrode inserted in their brains. This revealed changes in the moths’ neural activity when the projected sky image was rotated.

Read moreLions' record-breaking swim across channel captured by drone camera

Lions' record-breaking swim across channel captured by drone camera

Althoughdung beetles use the Milky Wayto stay on the same bearing over short distances, no insect was known to use celestial navigation for migration until now.

“The bogong moth is the first invertebrate we know of that is able to use the stars as a compass for long-distance navigation to a distant destination that it has never previously been to,” says Warrant. “Only humans and some species of night migratory birds are known to have this ability.”

Another insect famous for long-distance migrations, the monarch butterfly (Danaus plexippus),uses the sun to navigate, factoring in the time of day.

Cody Freasat Macquarie University in Sydney, Australia, says it is remarkable what insects can do with quite a simple visual system. “Stellar navigation really showcases the abilities of these small compound eyes in nocturnal insects to navigate across different cues – sun, moon and stars – as well as working even in extremely dim light levels,” says Freas.

Journal reference:NatureDOI: 10.1038/s41586-025-09135-3

NatureDOI: 10.1038/s41586-025-09135-3

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Tech CEOs and politicians alike are preparing for the day that superintelligent AI takes over, whilst failing to deal with the issues in front of them – from copyright to autonomous killing machines

Should politicians ensure that AI helps us colonise the galaxy, or protect people from the overreach of big tech? The former sounds more fun, but it shouldn’t be the priority.

Among the Silicon Valley set, superintelligent AI is viewed as a rapidly approaching inevitability, withtech CEOspromising that the 2030s will see a golden era of progress. That attitude has reached Westminster and Washington, with think tanks telling politicians to be ready to harness the power of incoming AI and the Trump administration backingOpenAI’s $500 billioninitiative for ultrapowerful AI data centres.

It all sounds exciting, but as the great and the good dream of superintelligence, what we might call “stupid intelligence” is causing problems in the here and now. One of the questions facing the AI sector is whether hoovering up vast swathes of the internet – a necessary part of training AI – is copyright infringement.

There are reasonable arguments on both sides. Proponents say that, just as you aren’t infringingNew Scientist‘s copyright by merely reading these words, AI learning should be treated the same. Detractors, meanwhile, now include entertainment giants Disney and Universal, which aresuing the AI firm Midjourneyfor reproducing images of everything from Darth Vader to the Minions. Only legislation can settle the matter.

We are heading towards a world in which machines could kill with little human oversight

We are heading towards a world in which machines could kill with little human oversight

The battlefields of Ukraine pose another thorny AI problem. While OpenAI’s Sam Altman has said he fears a superintelligent AI may one day kill us all, deadly stupid intelligence is already here. The Russia-Ukraine war is driving us towards a world in which, very soon,machines could kill with little human oversight.

Politicians have entirely failed to get to grips with this threat. The United Nations held its first meeting on regulating “killer robots” in 2014. A decade later, we are no closer to restricting their use. If our leaders are biding their time in the hope that a superintelligence will eventually solve their problems for them, they are very much mistaken.

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Knee osteoarthritis is often treated via non-drug therapies, and now we have an idea of which ones work best

Knee braces really do seem to relieve symptoms of osteoarthritis that affects the jointTom Werner/Getty Images

Knee braces really do seem to relieve symptoms of osteoarthritis that affects the joint

Knee braces and water-basedexerciseappear to be two of the most effective ways to ease the pain and stiffness caused by knee osteoarthritis. That is according to a review of 12 non-drug therapies, but higher-quality evidence is needed before this guides clinical practice.

The condition is caused by the wear and tear of cartilage that cushions the ends of bones, leading to inflammation,painand stiffness. Painkillers and anti-inflammatory drugs can relieve these symptoms, but can also have side effects, so clinicians typically recommend physical therapies, such as shoe insoles to relieve knee pressure, supporting the joint with tape or using laser therapy to promote cartilage healing.

Read moreRheumatoid arthritis could be treated by eating probiotic bacteria

Rheumatoid arthritis could be treated by eating probiotic bacteria

However, it is unclear how these methods compare. “A lot of reviews of treatments only look at how well a single therapy works,” saysSarah Kingsburyat the University of Leeds in the UK, who wasn’t involved in the latest research.

To fill this gap,Yuan Luoat the First People’s Hospital of Neijiang in China and colleagues analysed data from 139 randomised controlled trials that collectively assessed 12 approved or experimental physical therapies for knee osteoarthritis. Those trials together involved more than 9600 adults with the condition.

Some of them compared two or three physical therapies, while others tested one therapy against aplaceboor no treatment. The participants generally received some form of therapy for several weeks before completing surveys on their symptoms.

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Based on this, the researchers found that knee braces appeared to be the most effective at reducing pain and stiffness and improving mobility. This was followed by water-based exercise. “If you walk in a pool, you’re using your muscles, but you’re not putting force [that wears down cartilage] through your joint in the same way as if you were walking down the park,” says Kingsbury.

The order of effectiveness for the remaining tested treatments was: land-based exercise; high-energy laser therapy; firing high-energy sound waves at the knee; low-energy laser therapy; two ways of electrically stimulating nerves in the knee; taping the knee; stimulating the knee with electromagnetic waves; stimulating the knee with ultrasound waves; and wearing insoles.

For various reasons, the results aren’t strong enough that they should influence clinical practice, says Kingsbury. One reason for this is that many of the studies involved fewer than 50 participants and small samples can limit confidence in any findings. What’s more, the treatment period in each study ranged from less than a week to several months, meaning that some therapies may only appear more effective than others because they tended to be used for longer.

Another limitation is that the studies didn’t compare the physical therapies with drug treatments, or test the effectiveness of combining drug and non-drug therapies, says Kingsbury.

Still, ahead of further research, the review offers clues as to what works best, she says. “It is useful and important to have that ranking – maybe we can discount the bottom six or 10 [therapies] and really focus our efforts on improving the evidence around the top few.”

Journal reference:PLoS OneDOI: 10.1371/journal.pone.0324864

PLoS OneDOI: 10.1371/journal.pone.0324864

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The infected are back, over two decades since they first appeared in 2002's 28 Days Later — and this film is the best of the three, says film columnist Simon Ings

An infected in 28 Years LaterMiya Mizuno/Sony

Directed by Danny Boyle, written by Alex Garland

Here’s a bit of screenplay advice to nail above your desk: make your plots simple and your characters complicated.

We can polish off the story of28 Years Laterin a couple of paragraphs. It’s the belated third instalment in a series that began in 2002, with28 Days Later. A lab-grown neurotoxic virus has spread uncontrollable, orgiastic rage across continental Europe, creating an army of the infected (zombies, really, although they’re deliberately not referred to as such). The infection is eventually quarantined to mainland Britain. International fleets ensure that no-one leaves the island.

Adolescent boy Spike (Alfie Williams, a relative newcomer and definitely a face to follow) lives in the relative safety of a small northern island, connected to the mainland by a causeway that’s passable only at low tide. At 12 years old (rather young for the task, but his dad reckons he’s ready), Spike leaves for the mainland to be blooded. Amid trackless forests (though perhaps not quite trackless enough after 28 years; otherwise the film’smise-en-scèneis superb and chilling) Spike kills a very slowzombie, misses a blisteringly fast one, and generally gives a good account of himself.

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But it sits ill with Spike, once he’s home, to be cheered as a hero by all these drunken villagers, even as his mother (Jodie Comer) lies bedridden with a mysterious illness and his father Jamie (Aaron Taylor-Johnson) seeks distraction with another woman. So, Spike sneaks his mum off the island and sets out with her in search of the only doctor he’s ever heard of – a painted recluse who spends his days in the woods burning corpses.

The twist – and let’s face it, you’re agog for the twist – is that there is no twist. Having established the rules of this world in28 Days Later, writer Alex Garland has simply and wonderfully stuck to his guns. There are flourishes: a vanishingly small number of zombies have survived the initial viral outbreak to breed and become an almost-viable competitor species. Some of them now grow very big indeed, thanks to the steroid-like effects of the original infection. But these aren’t new attractions so much as patches and fixes, and they’re delivered very much in the make-and-mend-and-keep-going spirit that hangs over Spike’s doughty little island village.

The best science fiction movies to look forward to in 2025From M3gan 2 to 28 Years Later, this year is all about inventive sequels, series and remakes – plus some dazzling adaptations like Mikey 17, says Simon Ings

The best science fiction movies to look forward to in 2025

From M3gan 2 to 28 Years Later, this year is all about inventive sequels, series and remakes – plus some dazzling adaptations like Mikey 17, says Simon Ings

Nothing is quite as it seems – when is it ever? – and, every once in a while, Boyle mischievously intercuts Laurence Olivier’sHenry Vwith Great War newsreel and28 Weeks Laterzombie outbreak footage to imply a deeper, darker significance to the village’s homespun defence league and its culling expeditions. There are nods to folk horror, fromApocalypse NowandAliens 3toPredator. But this is not a tricksy movie, and its intent is clear: in this world so long steeped in horror, there’s going to be this human story, about loss and disillusion, about growing up and growing apart, about when to stand with others, and when to stand alone, all conveyed through the credible words and reasonable actions of largely unexceptional human beings.

The budget is modest (somewhere between $60 million and 75 million). The casting is meticulous (see how Christopher Fulford plays Spike’s grandfather with an effortless friendliness that all the while implies some harrowing backstory). And don’t get me wrong:28 Years Lateris full of invention, laden with fan-pleasing callbacks and cineastic cap-tugging. But never once does it cheat. There’s not a single fatuous MacGuffin pulling us through. No dumb quest. No magical grail. No grand unmasking. Only the feeling spilling from Alfie Williams’s eyes as young Spike learns, line by line and scene by scene, what he must acquire, and what he must let go, if he is to become a man in this world.

All credit toDays, whose fast-and-furious infected shocked and delighted us all in 2002; all credit, too, to 2007’sWeeks, an ingenious sequel and quite as good an expansion on its original asAlienswas toAlien. ButYearscarries the crown, at least for now (there’s another instalment coming).

Boyle and Garland have returned in triumph to territory they staked out (sorry, but thisisthe last paragraph) more than two decades ago.

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Restricting calories has been linked to living longer in many studies, and now it seems that the drug rapamycin has nearly the same effect, at least in animals

An illustration of the drug rapamycin (red) inhibiting the protein complex mTORC1, which has various effects on cellular functionSCIENCE PHOTO LIBRARY/Getty Images

An illustration of the drug rapamycin (red) inhibiting the protein complex mTORC1, which has various effects on cellular function

SCIENCE PHOTO LIBRARY/Getty Images

The drugrapamycinseems to have more or less the same life-extending effect as restricting calories, according to the largest study yet of longevity in different vertebrate species.

Scientists are investigating whether interventions like dietary tweaks and exercise could help us live longer while reducing thehealthimpacts of ageing. Restricting calorie intake while ensuring essential nutrient needs are met, for example,has been shown to extend the lifespan of non-human animalsby as much as 40 per cent.

Read moreThe shocking discovery that our gut microbiome drives ageing

The shocking discovery that our gut microbiome drives ageing

“Anyone in the field who’s paying attention, I think we all have known for a long time that caloric restriction usually works – and by works, I mean increases lifespan,” saysMatt Kaeberleinat the University of Washington in Seattle, who wasn’t involved in the latest research.

Another approach garnering interest is potential anti-ageing drugs, such as rapamycin, which was originally developed as an immunosuppressant. A combination of rapamycin and the cancer drug trametinibwas shown earlier this year to increase lifespan in miceby 30 per cent.

Now,Zahida Sultanovaat the University of East Anglia, UK, and her colleagues have looked at data from 167 studies of lifespan interventions across eight vertebrate species, including fish, mice, rats and rhesus monkeys, but not humans.

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The researchers found that dietary restriction, whether via intermittent fasting or just generally cutting calories, extended the lifespan of all eight species, for both males and females – and rapamycin seems to have roughly the same effect. They also looked into the potential of the type 2 diabetes drug metformin, which has similarly been touted as a potential life-extender, but found no longevity benefit.

People shouldn’t start taking rapamycin off the back of these results, though, says Sultanova. “Rapamycin, especially high doses, has side effects because it is supposed to suppress your immune system,” she says, adding thatstudies in mice show it can disturb reproduction. Yet preliminary data from one trial recently indicatedthat low doses of rapamycin are relatively safe in healthy older adults.

The radical new theory that wrinkles actually cause ageingForget vanity, there is a much better reason to care about your laughter lines – wrinkles may be driving ageing in your body and brain via zombie-like senescent cells

The radical new theory that wrinkles actually cause ageing

Forget vanity, there is a much better reason to care about your laughter lines – wrinkles may be driving ageing in your body and brain via zombie-like senescent cells

Kaeberlein also says that people shouldn’t take any medication or restrict their calorie intake in an attempt to stave offageing, with the latterbeing linked to physical weakness and mental health issues. “I think we need to know more about the risk-reward ratio in humans before we can make those sorts of determinations,” he says. “I believe rapamycin will have benefits for some people and we’re learning more and more about who those people are likely to be.”

Otherdrugsthat work similarly to rapamycin, known as rapalogs, could hold more promise if they can extend lifespan with even fewer side effects, says Sultanova.

Kaeberlein says the results fit the patterns he has seen in the literature, but adds that “you always have to be careful when you’re looking across different species because the magnitude of effects that we see in shorter-lived organisms are usually larger than the magnitude we see in longer-lived organisms”.

Journal reference:Aging CellDOI: 10.1111/acel.70131

Aging CellDOI: 10.1111/acel.70131

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Recovering "revenge addict" James Kimmel Jr. makes the case for retaliation to be understood as an addiction in new book The Science of Revenge. It's compelling, but doesn't quite add up

Was the UK’s iconic Sycamore Gap tree felled in an act of revenge?VAUGHAN/EPA-EFE/Shutters​tock

Was the UK’s iconic Sycamore Gap tree felled in an act of revenge?

The Science of RevengeJames Kimmel Jr. (Harmony Books)

Few people may readily own up to thirsting for revenge – yet it is undeniable that some of us do.

From US President Donald Trump’sfixationon score-settling to the “cancel culture” of policing on social media, and maybe even thefellingof the iconic Sycamore Gap tree in the UK – possibly an attempt at payback due to one of those found guilty being at risk of eviction – revenge may be more plausible than love as the force that makes the world turn. Could we even go so far as to call it an addiction?

James Kimmel Jr. argues passionately that we can – and we must, if the world is ever to become a more compassionate place. His new bookThe Science of Revenge: Understanding the world’s deadliest addiction – and how to overcome itreflects his efforts, over more than a decade, to improve our understanding of the neurology drivingrevengeand to recognise its deadly toll.

You can’t deny Kimmel’s credentials: he is alecturer in psychiatryat Yale University, where heleads studiesinto motive control, and a lawyer. As a former civil litigator, resolving non-criminal disputes, he saw how the law could be abused to progress personal grievances and punish perceived enemies, especially by the wealthy and powerful.

He also understood the impulse, he writes. Growing up in rural Pennsylvania in the early 1980s, he was bullied and his family intimidated. Their dog was even shot dead. After their mailbox was blown up, the teenage Kimmel ended up pulling a gun on his tormentors – but not the trigger.

Still, Kimmel writes, his unresolved grievances ended up leading him into law – “the professional revenge business”. After a mental breakdown, he began researching his pet theory of “revenge addiction”, pivoting to psychiatry to progress it.

Today, Kimmel points to himself as a “recovering revenge addict”, as well as to years of scientific inquiry, to make the case for “compulsive revenge seeking” to be understood as an addiction and a brain disease.

Kimmel says the desire for revenge registers in some people’s brains in much the same way as narcotics

Kimmel says the desire for revenge registers in some people’s brains in much the same way as narcotics

He argues that the desire for revenge registers in the brains of some individuals in much the same way as narcotics, activating cravings, overriding impulse controls and “satisfying the same brain-biological desire for relief of pain and hedonic reward”.

If borne out, writes Kimmel, this idea could not only explain “the desire to hurt and kill”, but also present a possible path forpreventing violence. He suggests that by identifying people with a tendency to feel victimised, nurse perceived grievances and ruminate on retaliation, it may be possible to stop mass shootings and other deadly outbursts in their tracks.

To make his case, he references much credible research about reward, revenge and forgiveness. He is up front about the limits of their application or relevance to his concept of revenge addiction, and includes sceptical expert voices alongside those who agree there may be something to it.

However, his eagerness to credit revenge as the cause of “all the wars, murders, and physical and psychological assaults throughout human history” may put readers off as much as it persuades them.

Kimmel doesn’t deny the relevance of “genetic factors, early trauma, or psychosocial and environmental circumstances”, and says revenge addiction isn’t intended to excuse people who commit violent crimes. But that is often the impression he creates, such as when he likens experiencing a bout of potentially murderous “revenge cravings” to a heart attack.

This is both confusing and clumsy. Kimmel is most compelling when he tells the stories of people who escaped lives shaped by hate, such as a former Ku Klux Klansman who now helps others. But his fixation on revenge as the root of all evil risks pushing nuance and other contributing factors (such as misogyny or childhood sexual abuse) to the side.

His analyses of mass murderers’ manifestos and the psychologies of Adolf Hitler, Joseph Stalin and Mao Zedong via the narrow (at best) lens of revenge addiction sit particularly uncomfortably. Revenge may be under-acknowledged as a motivating force throughout history, but Kimmel may be too close to his subject.

Elle Hunt is a writer based in Norwich, UK

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