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THE early universe appears to be littered with enormous, star-like balls of gas powered by a black hole at their core, a finding that might solve one of the biggest mysteries thrown up by the discoveries of the James Webb Space Telescope (JWST). When JWST first began peering back to the universe’s first billion years, astronomers found a group of what looked like extremely compact, red and very bright galaxies unlike any we can see in our local universe. The most popular explanations for these so-called little red dots (LRDs) were supermassive black holes with dust swirling around them, or galaxies very densely packed full of stars – but neither one fully made sense of the light JWST was detecting. Earlier this year, astronomers proposed instead that LRDs were dense…

THE odd phenomenon of quantum superposition has helped researchers break a fundamental quantum mechanical limit – and given quantum objects properties that make them useful for quantum computing for longer periods of time. For a century, physicists have been puzzled by exactly where to draw the line between the quantum world of the small and the macroscopic world that we experience. In 1985, physicists Anthony Leggett and Anupam Garg devised a mathematical test that could be applied to objects and their behaviour over time to diagnose whether they are big enough to escape quantumness. Here, quantum objects are identified by the unusually strong correlations between their properties at different points in time, akin to their behaviour yesterday and tomorrow being unexpectedly related. Objects that score high enough on this test…

THE Arctic may retain about 1.5°C of warming even if the carbon dioxide in the atmosphere returns to pre-industrial levels. “These findings highlight the irreversible nature of Arctic climate change even under aggressive CDR [carbon dioxide removal] scenarios,” wrote Xiao Dong at the Institute of Atmospheric Physics in Beijing and his colleagues in their study. This is because the ocean, which has absorbed 90 per cent of the heat from global warming, will continue heating the Arctic for centuries even if the atmosphere cools down. “Even if you get the atmosphere cooling, the ocean will be lagging behind that,” says Michael Meredith at the British Antarctic Survey. Dong and his colleagues predicted the Arctic’s potential to retain heat using 11 independent climate models. They analysed an abstract scenario where atmospheric CO₂…

MEN should ejaculate less than 48 hours before in vitro fertilisation egg collection to maximise the chances of it leading to an ongoing pregnancy, according to the first clinical trial to test how different ejaculation abstinence intervals affect the success of the fertility treatment. Towards the end of an IVF cycle, the woman takes a “trigger” drug that pushes developing eggs to maturation. This is injected 36 hours before the eggs are collected and fertilised. To ensure the healthiest possible sperm for fertilisation, men are usually advised to ejaculate within a window of between two and seven days before providing the sample that will be used for IVF. “There is an optimal period between ejaculations when sperm are at their best,” says David Miller at the University of Leeds, UK,…

KILLER whales and dolphins have been working together to hunt salmon in the northern Pacific Ocean, an unexpected finding that further reveals the complex social lives of marine mammals. Video cameras and sensors attached to nine killer whales – also known as orcas – showed four of them diving with numerous Pacific white-sided dolphins towards Chinook salmon hiding in the depths off northern Vancouver Island. Three more whales were observed by drone. The orcas ate the salmon, while the dolphins scavenged the scraps (Nature Scientific Reports, doi.org/hbfgfz). “They were cooperatively foraging,” says Sarah Fortune at Dalhousie University in Canada. “You could anthropomorphise it and say that they’re being friends.” Also known as king salmon, Chinook salmon can grow more than a metre long and are often too big for dolphins to…

A GENETIC technology known as a gene drive could help prevent malaria by spreading genes in wild mosquitoes that stop them transmitting the parasite. Tests in a lab in Tanzania have now confirmed that one potential gene drive should achieve this if it were released in the country. “It would be a game-changing technology, that’s for sure,” says George Christophides at Imperial College London. A specific piece of DNA in the genome of an animal is normally passed on to only half its offspring, because a parent’s DNA is divided in half among egg or sperm. Gene drives increase this proportion, meaning a bit of DNA can spread rapidly through a population even if it provides no evolutionary benefit. There are many natural gene drives that work via all kinds…

A MARS crater may have once contained water that sloshed back and forth as a tide came and went. If that is true, Mars must have had a moon that was massive enough to exert a gravitational pull on the planet’s seas sufficient enough to create tides – one that was bigger than either of its current moons. Suniti Karunatillake at Louisiana State University and his team saw that traces of tidal activity seem to be preserved in thin layers within sedimentary rocks in Gale crater. They analysed the layers to obtain the period of the tides and the properties of the moon that helped cause them. If it existed, it was 15 to 18 times as massive as Phobos, Mars’s largest moon. Karunatillake presented the results at the annual…

THE health of populations in Britain declined under Roman occupation, particularly in more urban areas. There is a widely held belief the Romans brought civilisation to those they conquered, perhaps best exemplified in Monty Python’s Life of Brian, in which John Cleese’s character asks “What have the Romans ever done for us?” Yet researchers are aware that there was a decline in the health of the population in Iron Age Britain after the Romans conquered the territory in AD 43 – and that populations thrived after they left. Now, Rebecca Pitt at the University of Reading, UK, has studied 646 ancient skeletons, 372 belonging to children who were less than 3.5 years old when they died, and 274 from adult females aged between 18 and 45 years old. These came…

EARTH may owe some of its properties to a nearby star that blew up as the solar system was forming – a pattern that could be ubiquitous across the galaxy. The solar system used to be filled with heat-producing radioactive elements that quickly decayed. The heat from these elements drove off large amounts of water from the space rocks and comets that came together to form Earth, ensuring the planet had the right amount of water for life to develop. It is unclear how these elements reached the solar system. Many are found in supernova explosions, but simulations of close-by supernovae struggle to produce the exact ratios of elements needed. Now, Ryo Sawada at the University of Tokyo in Japan and his colleagues have found a supernova slightly further away,…