Tabla de contenidos para 26 July 2025 en New Scientist

NS Live How the brain invents your reality Join Daniel Yon on 18 October at Excel London as he delves into how our brains interpret the world around us, from physical objects to social interactions. Drawing on the latest research in neuroscience and psychology, he reveals that our brains, much like scientists, use past experiences to build models and predict reality. newscientist.com/nslive Tour The geology of the Pyrenees: Spain Discover the dramatic beauty and rich heritage of the Spanish Pyrenees on a journey that blends vibrant culture, world-class geology and unforgettable landscapes. Wander medieval villages, step inside majestic cathedrals and walk a stretch of the legendary Camino de Santiago. This seven-day tour starts on 14 September and costs £4300. newscientist.com/tours Podcast The world, the universe and us This week, the…

COULD our universe be expanding then shrinking back into a tiny point, reliving a kind of big bang over and over again? Probably not, according to a mathematical analysis that argues that the laws of physics forbid such a cyclic universe. A key moment in the life of a cyclic universe is the big bounce, an alternative to the big bang as the beginning of the universe we see around us. The big bang starts with a singularity – matter and energy packed into a point so dense that gravity becomes strong enough to elude the laws of physics as we understand them – followed by an endless outwards expansion. But if the universe began with a big bounce, we could look beyond what we generally think of as the…

RAPID erosion due to ranching and farming has stripped the Alps of almost all the soil formed since the retreat of glaciers. This soil developed over millennia as plants, microbes and weather transformed hard rock into the carbon-rich foundation of this mountain ecosystem. “We destroyed the soils at a rate four to 10 times faster than they grew,” says William Rapuc at the French National Centre for Scientific Research. He and his colleagues studied lithium isotopes in sediments from Lake Bourget in the French Alps to reconstruct patterns of soil erosion from the surrounding region over the past 10,000 years. Because certain lithium isotopes are enriched as clay and other minerals form from the parent rock, they can tell you if the soils are developing or eroding, says Rapuc. They compared…

ROCKS in Australia preserve evidence that plates in Earth’s crust were moving 3.5 billion years ago, a finding that pushes the beginnings of plate tectonics back by hundreds of millions of years. Today, around eight vast, rigid plates of rock at the surface of the planet, plus some smaller plates, are pulled or pushed along a softer layer of rock beneath. But geologists disagree over how many plates there once were, when they started moving and how they used to move. The strongest evidence for a start date was about 3.2 billion years ago. Geologists can use hints from the chemical composition of rocks to infer how those rocks moved in the past. However, there is little record of how early plates may have moved relative to each other. Now,…

A SHORT nap during the day seems to increase the overall amount of sleep a young child gets, rather than being a serious threat to night-time slumbers. Babies and young children typically nap during the day, a habit that has been linked to the development of early memories. This trend usually stops between the ages of about 3 and 5, but the timing varies, leaving many parents unsure as to whether their child should nap or not. In France, children start a form of preschool at 3 years old, which presents a dilemma of whether staff should let them nap. “Some parents and teachers are concerned that napping during the day might interfere with night-time sleep or reduce valuable learning time,” says Stéphanie Mazza at the University of Lyon in…

SUPER-SALTY underwater lakes rich in carbon dioxide could host extreme life forms unlike any others on Earth. Water rich in salt sinks to the bottom of the ocean and can collect in depressions in the sea floor as a liquid lake that is distinct from the water above. The unique chemical make-up of these brine pools – low in oxygen and rich in certain minerals – makes them places where extreme microorganisms can evolve and thrive. Now, Froukje van der Zwan at King Abdullah University of Science and Technology in Saudi Arabia and her colleagues have discovered a new type of brine pool that is warm, rich in CO₂ and appears to be fed by underwater volcanoes. On a recent expedition to two underwater volcanoes in the Red Sea, Hatiba Mons…

MOST people would find a 1200-metre wall of ice on a mountain peak intimidating. But for decorated ice climber Ines Papert, scaling the peak of Kyzyl Asker – a remote mountain on the border between China and Kyrgyzstan – was a dream. It took three attempts before she and fellow climber Luka Lindič summitted it in 2016 (far left), becoming the first known people to climb a precipitous route the pair dubbed “Lost in China”. Papert is one of more than a dozen female mountaineers whose daring expeditions to the world’s greatest peaks are featured in Mountaineering Women: Climbing through history by Joanna Croston. Another is mountaineer Elizabeth “Lizzie” Le Blond, photographed climbing a mountain in the Swiss Alps in 1889 in a full skirt (top, near left). Le Blond,…

A CHILD in the UK died from measles this month. A baby in Canada died from measles in June. Two children in the US have died from measles this year. But it didn’t have to be this way. Measles is a preventable disease – yet we have regressed to a point where we are acting as though it isn’t. And if we don’t move quickly to right the ship, we could see cases of other preventable diseases rise as well. The US is in the throes of its largest measles outbreak since it eliminated the virus in 2000. More than 1300 cases have been confirmed – the highest number in 33 years. And it isn’t alone. In 2024, Europe reported its highest caseload in more than 25 years, doubling that…

IT TURNS out that obesity may be much more complicated than we thought, with the condition potentially existing in up to 11 forms, each caused by distinct biological pathways. “It’s not just about the body mass index or the body appearance; it’s more about the biology behind it and how that is related to risk factors,” says Akl Fahed at the Broad Institute in Cambridge, Massachusetts. The World Health Organization defines obesity as having excess fat that poses a risk to health. Whether someone has it is worked out by calculating their body mass index (BMI), a measure of weight relative to height. As not everyone with obesity has health complications, some researchers have recently suggested introducing a category of “preclinical” obesity. This splits people with the condition into two…

MUSIC isn’t just entertainment. It is one of the most accessible and powerful ways to regulate our mental state, yet we continue to underestimate its potential. It is time for society to embrace the therapeutic power of music not only in clinical settings, but also in our everyday lives. We already know that music can stir emotions – soothe our nerves, lift our mood, make us cry. But over the past few years, research in my lab at the University of Bergen, Norway, suggests it can change the content of our thoughts. In our 2019 study, participants listened to heroic or sad-sounding music while their minds wandered. The results were striking: the uplifting music triggered energising, constructive thoughts, while the sad music evoked calmer or more demotivating ones. This influence…

MANY of us will lose an adult tooth in our lifetime, whether through disease or misadventure – a punch that landed, a skateboarding trick that didn’t, say. And if you join their ranks, which include the nearly 178 million adults in the US who have lost at least one tooth, your options are pretty much the same as they have been for millennia: artificial replacement. Dental technology has moved on since the ancient Etruscans fashioned fake teeth from oxen bones, but not much. The metal implants we use today tend to fail over time, causing significant pain when they do. But what if there were another way? What if, instead of implants and dentures, you could regrow lost teeth? That’s the question a journalist asked Paul Sharpe about 20 years…

Quick crossword #188  Set by Richard Smyth Scribble zone Answers and the next cryptic crossword next week ACROSS 1 Mathematical fractal developed in the 1970s (10,3) 8 Regularly updated personal website (4) 9 Hypothetical journeying into the past or future (4,6) 10 p+ (6) 11 W (8) 12 Large, hairy spider of the family Theraphosidae (9) 14 Cadaver, perhaps (4) 15 Route (4) 16 GHz (9) 20 Rectangular arrays of numbers or expressions (8) 21 Inverse function, in trigonometry (6) 23 Study of Fe, Pb or Au, perhaps (10) 24 Hydrated form of silica (4) 25 Notably infectious individual (5-8) DOWN 1 Mosquito-borne disease (7) 2 Period between sunset and sunrise (5) 3 Of a species, no longer living (7) 4 Mechanical device that bends when heated (10,5) 5 C8…

IF YOU told a child to stay “well away” from a cliff edge, how close to the edge could they creep before you started shouting for them to turn back? That is the question puzzling climate scientists right now, as it looks almost certain that we will breach the global commitment to limiting warming to no more than 1.5°C above pre-industrial levels. As we enter the danger zone, what comes next? “Governments have set themselves 1.5°C targets. But what those mean in a world where we’re already past 1.5°C is harder and harder to understand,” says Robin Lamboll at Imperial College London. “I think it would be very helpful if people started talking much more concisely and concretely about the actual goals they have in mind.” Those national targets are…

TWO snow leopard dens, home to five cubs, have been discovered in Mongolia’s Tost mountains, offering a rare opportunity to get data on this threatened species. Prior to this expedition, which happened in June and July, researchers hadn’t been able to visit a snow leopard den anywhere in the world since 2019. “The dens are in narrow cracks or caves,” says Örjan Johansson at the Snow Leopard Trust. “We only get one chance. If the mother returned before we were able to locate the den, we would have to abandon the search. Going back twice would be too intrusive.” Johansson and Buren Nyam, a local field ranger, established the approximate locations of the dens by tracking GPS collars that had previously been fitted to 20 adult female snow leopards. “A…

CHILDREN with anorexia nervosa have widespread brain changes that can’t be explained by their eating patterns alone. The finding brings us closer to identifying the neurological processes behind the condition, which could lead to better treatments for it. Anorexia nervosa, an eating disorder characterised by severe calorie restriction and distorted body image, is poorly understood. Previous research has shown that the brain’s outer layer, called the cortex, is significantly thinner in people with the condition than those without it. But it isn’t clear the degree to which these changes are the result of malnutrition or an indication of the cause of anorexia. Clara Moreau at the University of Montreal in Canada compared brain scans from children with anorexia with those with avoidant/restrictive food intake disorder (ARFID). Both conditions involve severe…

Marvin the Paranoid Android, The Hitchhiker’s Guide to the Galaxy series by Douglas Adams (1979) Marvin is a Sirius Cybernetics Corporation prototype of GPP (Genuine People Personalities) tech. In truth, he shows little sign of paranoia, but he is certainly depressed, and no wonder: a robot with a brain the size of a planet destined for subservience. He did lend his name to one of Radiohead’s finest songs, which might have cheered him up a bit. Matthew Sparkes BB8, Star Wars: The Force Awakens (2015) When I think of Star Wars, the first droid that comes to mind is the one I favoured in my childhood: R2D2. Which is why I was a little unsure when BB8 blasted onto the scene in the final trilogy like a soccer ball from…

Effortless ride When driving over hills, which is more fuel-efficient: accelerating downhill for uphill momentum or maintaining a steady speed? Eric Kvaalen Les Essarts-le-Roi, France It is more fuel-efficient to maintain a steady speed because the total energy used depends on the average air resistance. Since air resistance is proportional to the square of speed, your average resistance will be lower at a steady speed, compared with going fast and then slow at the same average speed. However, there are other considerations. When going downhill, you can save fuel by pushing the clutch so that the engine turns at idle. And if you are going over the top of a hill, allow gravity to slow down and speed up your vehicle, rather than using fuel to keep your speed constant…