Neanderthal–human baby-making was recent — and brief

Mixing between Neanderthals and Homo sapiens lasted less than 7,000 years — a remarkably short time considering that almost every living individual not of African ancestry carries a substantial amount of Neanderthal DNA. Researchers compared the genomes of individuals who lived between 2,200 and 45,000 years ago with those of modern people and found that the genetic intermingling started around 47,000 years ago. It ended around the time when Neanderthals went extinct.

Counting crows

Carrion crows (Corvus corone) can reliably caw a number of times from one to four on command — a skill that had only been seen in people. Over several months, birds were trained with treats to associate a screen showing the digits, or a related sound, with the right number of calls. The crows were not displaying a ‘true’ counting ability, which requires a symbolic understanding of numbers, say researchers. But they are nevertheless able to produce a deliberate number of vocalisations on cue.

Bizarre bacteria scramble workflow of life

Bacteria have stunned biologists by reversing the usual flow of information. Typically genes written in DNA serve as the template for making RNA molecules, which are then translated into proteins. Some viruses are known to have an enzyme that reverses this flow by scribing RNA into DNA. Now scientists have found bacteria with a similar enzyme that can even make completely new genes — by reading RNA as a template. These genes create protective proteins when a bacterium is infected by a virus.

Elusive element coaxed into compound

Promethium, a rare and mysterious radioactive element from the far reaches of the periodic table, has been made into a ‘complex’ for the first time. In this type of compound, promethium is bound to a few surrounding molecules. The feat fills a long-standing gap in our knowledge of chemistry and could lead to better methods for separating promethium from similar elements in nuclear waste, for example.

A Chinese-language ChatGPT

The Chinese-made chatbot ChatGLM performs as well as ChatGPT on many measures and even outperforms it in Chinese, say its creators. Models that are tailored to different languages avoid “oversimplifying or neglecting the specific characteristics of certain languages and cultures”, says machine-learning specialist Adina Yakefu. Although ChatGPT and many of its rivals can respond in a variety of languages, most of them are built by US companies and mainly use English. By contrast, ChatGLM is designed to work in both Chinese and English.

Lab-grown sperm and eggs: ‘epigenetic’ reset in human cells paves the way

Researchers have discovered a protein that promotes an ‘epigenetic’ reset in human cells — a small but crucial step in their development into sperm or eggs. The epigenome affects whether genes are turned on or off, and helps to differentiate, for example, a brain cell from a liver cell. The cells in the study stopped developing further after epigenetic reprogramming, so before we can grow eggs and sperm in a dish.

First ‘bilingual’ brain-reading device decodes Spanish and English words

An AI-powered brain implant has helped, for the first time, a paralysed bilingual person speak in both their languages. An artificial intelligence (AI) system decodes the man’s neural patterns and interprets the language he’s using — English or his native Spanish — based partly on which combination of words makes the most sense.

Found at last: long-lost branch of the Nile

The remains of an ancient branch of the Nile River has been found near the Giza pyramid complex in Egypt — hinting at why so many were built there. The pyramids there are now many kilometres away from the Nile. Satellite images and geological data now confirm that a tributary of the river — which researchers have named the Ahramat Branch — used to run nearby several thousand years ago. The waterway would have provided a convenient way to transport materials to the sites.

‘Quantum internet’ demonstration in cities is most advanced yet

Three research teams were each able to create quantum-entangled states over several kilometres of existing optical fibres in real urban areas. Entanglement is when two or more objects are linked so that they contain the same information even when they are far apart.

Human embryos embrace asymmetry to form the body

The two cells that make up a one-day old embryo make dramatically different contributions to a human body. This is contrary to the idea that embryonic cells don’t specialise until later in development. Studies with mice, and now with human embryos, have shown that one of the first two cells develops to become most of the mammalian body, whereas the other mainly forms the yolk sac. The cell that divides faster seems to form the body, but it’s not clear why this preference develops. The finding could eventually improve screening for in vitro fertilisation to select embryos more likely to develop into a fœtus and lead to successful pregnancies.

How does ChatGPT ‘think’?

Researchers are borrowing approaches from psychology and neuroscience to crack open the ‘black box’ of artificial intelligence (AI) systems.

Brain-reading device is best yet at decoding ‘internal speech’

A brain-computer interface device is the first to decode words entirely from neuronal recordings, without the aid of spoken or mimed speech. The system used arrays of tiny electrodes implanted in the brains of two people with spinal-cord injuries. It decoded one participant’s imagined speech with 79% accuracy and the other’s with 23% accuracy. Some neurons were active only during internal speech and not when the person spoke aloud, suggesting the brain processes imagined speech differently. Clinical applications are still a long way off.

Cubic millimetre of brain mapped in spectacular detail

Researchers have created an exquisitely detailed atlas of a tiny piece of one woman’s brain, which had been removed during surgery to treat her epilepsy. The sample was cut into thousands of nanometre-thick slices and each was imaged with electron microscopes. AI tools then classified different structures and cells, and created a 3D reconstruction of the sample.

Breakthrough paves way for ultra-precise ‘nuclear’ timekeepers

Researchers have used a laser to prompt tiny energy shifts in an atomic nucleus — a major step towards building nuclear clocks. These could be around 10 times more accurate than the world’s current best timekeepers, known as optical clocks, and less sensitive to disturbances. To turn the system into an actual clock, physicists will need to build higher-resolution lasers that nudge the nucleus with more precision.

Optical Clock

Discovery of atmosphere on an Earth-like exoplanet

Investigations using the James Webb Space Telescope have confirmed that the exoplanet 55 Cancri e has a carbon-based atmosphere — the first time an atmosphere has been detected surrounding a rocky planet similar to Earth outside the Solar System. The planet orbits very close to its Sun-like star and can’t support life as we know it, in part because it is probably covered by a magma ocean.

New Kind of Dinosaur Egg Discovered

Palæontologists have discovered dinosaur eggs in eastern China that were softer and less brittle than hard-shelled eggs — but not quite soft-shelled either. The eggs, which date back to some 66-145 million years ago, suggest that dinosaurs were more diverse than previously assumed.

What if dark energy is weakening?

A pioneering cosmic-mapping project seems to show that dark energy could be getting weaker, with potential implications for theories of how the Universe has evolved and for what its future might hold. The mysterious force is like reverse gravity, pushing everything apart and causing the Universe to expand faster and faster, getting colder and emptier. Initial results from the Dark Energy Spectroscopic Instrument in Arizona hint that dark energy is not a constant after all, which means the Universe’s expansion could start to slow down. But researchers say that the evidence for changes in dark energy is still very uncertain.

Mediæval graves reveal secrets of the Avars

DNA has been extracted from ancient graves in four cemeteries in Hungary that were once at the heart of a mysterious nomadic culture. The Avars were nomadic people who migrated to eastern and central Europe from the late sixth century to the early ninth century. The researchers analysed genomes from 424 individuals using computational techniques to connect distant family members through their shared DNA, including a nine-generation family tree. The data suggest that the Avars kept aspects of their cultural heritage from the Asian steppes, such as very strict rules against inbreeding.

Bioluminescence evolved 540 million years ago

An ancient group of glowing corals pushes back the origin of bioluminescence in animals to more than half a billion years ago. Tiny crustaceans that lived around 270 million years ago were previously thought to be the earliest glowing animals. Genetic analysis and computer modelling revealed that octocorals probably evolved the ability to make light much earlier, around the time when the first animals developed eyes.

Fossil snake discovered in India may have been the largest ever

Fossil vertebrae of possibly the longest snake to have ever lived have been unearthed in a coal mine in India. Researchers recovered 27 vertebrae of a snake estimated to reach up to 15 metres in length, more than twice that of the longest snakes alive today, reticulated pythons (Malayopython reticulatus), and probably slightly longer than the extinct Titanoboa. The snake, dubbed Vasuki indicus, lived 47 million years ago.

Your perception of time is skewed by what you see

When people look at larger, less cluttered scenes — a big, empty warehouse, for example — they think they viewed it for longer than they actually did. Similarly, people experience time constriction when looking at more constrained, cluttered scenes, such as an image of a well-stocked cupboard. The study of 52 participants also showed that people are more likely to remember the images they thought they viewed for longer.

Physicists debate Universe-expansion data

Hopes that the James Webb Space Telescope (JWST) would finally settle the debate over how fast the Universe is expanding were dashed after two teams that used JWST data calculated different values. Observations of the current Universe typically find the expansion rate — the Hubble constant — to be about 9% faster than predictions based on early-Universe data.

Animal consciousness needs a rethink

A coalition of scientists has published a declaration that there is “a realistic possibility of conscious experience” in all vertebrates and in many invertebrates, such as octopuses and insects. The group focuses on sentience — an aspect of consciousness often defined as being able to have subjective experiences — pointing to research suggesting that octopuses feel pain and that bees show play behaviour.

The Secret to the Strongest Force in the Universe

Physicists are finally getting to grips with the mysterious strong force, which binds quarks into protons and neutrons and holds the nucleus together. The physicists who made the first measurements in the range of distances where the strong force becomes especially strong and difficult to calculate, and came up with theoretical predictions to match, describe their breakthrough. We at last have the ability to calculate aspects of quantum chromodynamics — the fiendishly complex theory that describes how the force works — from first principles

Hyperphantasia and the quest to understand vivid imaginations

Some people experience intense visual imagery, called hyperphantasia, that means they can replay memories or imagine scenes that are as vivid as real life. Once thought to be rare, research now suggests as many as 1 in 30 people have such vivid imaginations. At the other end of the spectrum are people with ‘aphantasia’, who have no visual imagery at all. Science is just catching up with this neurodiversity and how it influences memory, childhood, and even mental health.

Violent volcanoes shaped Jupiter’s moon

The most volcanically active place in the Solar System, Jupiter’s moon Io, has been shaped by volcanoes for billions of years. Lava and ash spewing from hundreds of volcanoes continuously resurface Io, obscuring any physical evidence of its history. Scientists now used sulphur in the moon’s atmosphere as “a tracer for studying Io’s long-term evolution”, explains planetary scientist and study co-author Katherine de Kleer. Because lava on Io is thought to be similar to magma on early Earth, “Io’s volcanism might be giving us a window into the mechanisms of volcanism and Earth’s early history”, she adds.

Goldene: a single layer of gold atoms

Goldene is a cousin of graphene, the single-atom-thick sheet of carbon first discovered in 2004 — but made of gold. Goldene is roughly 400 times as thin as the thinnest commercial gold leaf, and might find use as a catalyst, or in light-sensing devices.

Three new species of extinct giant kangaroos

Researchers have identified three new giant kangaroo species that lived around 5 million to 40,000 years ago. One of them, Protemnodon viator, weighed up to 170 kilograms — about twice as much as the largest living kangaroos. While most Protemnodon species were thought to move on four legs, viator had long limbs and could probably hop long distances.

Algae that can fix nitrogen

A new organelle that can turn atmospheric nitrogen into biologically useful molecules has been discovered in a marine alga. It’s the first time nitrogen fixation has been recorded in eukaryotes (the group of organisms that includes plants and animals). The discovery offers hope that crops could one day be engineered to grab nitrogen from the air — essentially making their own fertiliser.

First direct image of a Wigner crystal

A Wigner crystal — a structure made entirely of electrons — has been imaged directly for the first time. Until now, there had only been indirect evidence of the crystal, which forms at low temperatures. Using high-resolution scanning tunnelling microscopy, the team saw the electrons inside two thin graphene sheets arrange themselves into a triangular lattice, just like physicist Eugene Wigner predicted in 1934.

Ritual sacrifice across Stone Age Europe

Evidence from burial sites across Europe might point to a common ritual involving human sacrifice. Shared characteristics — such as the style of killing, broken grindstones, remnants of animal sacrifices and round, silo-like structures — suggest that these rituals might have been a widespread practice amongst cultures that were otherwise quite different.

Blackfoot people’s ancient ice age lineage

Modern Blackfoot people are closely related to the first humans that populated the Americas after the last ice age. DNA analysis of six modern and seven historic individuals shows that they belong to a previously undescribed genetic lineage that extends back to more than 18,000 years ago. The data add to evidence from Blackfoot oral traditions and archaeological findings, and could support the claims that these people have to ancestral lands.

First planet with a permanent dark side

Super-Earth LHS 3844b is the first exoplanet to show convincing signs of tidal synchronisation, meaning one of its hemispheres is permanently illuminated by its star and the other is in permanent darkness. The planet is relatively cool, indicating that it lacks the tidal heating non-locked planets experience. It’s unclear whether tidally locked planets could be habitable.

First humans out of Africa stopped at Persian Plateau on way to Eurasia

After Homo sapiens expanded out of Africa 70,000 years ago, they seem to have paused for some 20,000 years before colonising Europe and Asia. Now researchers think they know where. Looking at ancient and modern DNA, and the environment of the time, scientists have pinpointed the Persian Plateau — which in this definition encompasses Iran, the United Arab Emirates, Kuwait and parts of Oman — as the perfect place. Finding local archaeological evidence to confirm this could be difficult.

Wild Birds Gesture ‘After You’ to Insist Their Mate Go First

Japanese tits (Parus minor) flutter their wings to invite their mate to enter the nest first. Scientists who observed eight breeding pairs of wild tits noticed that when one of the birds sat in front of the next box and fluttered its wings, the other would go in first. It’s the first documented evidence of birds using a symbolic gesture: one that has a specific meaning (like waving ‘goodbye’) but isn’t simply pointing at an object of interest.

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Birds behaviourally demonstrate what they want another to do. This is also a way of teaching chicks. See Rainbow Lorikeet Semiosis

Weird electron behaviour thrills physicists

Two teams have observed that electrons, which usually have a charge of –1, can behave as if they had fractional charges (such as –⅔) — and do so without being nudged by an external magnetic field. It’s the first time this ‘fractional quantum anomalous Hall effect’ has been observed experimentally, and physicists are scratching their heads over exactly how it works. It’s a fundamental discovery that might also someday have practical applications: fractionally charged particles are a key requirement for a certain type of quantum computer.

Scientists discover that like-charged particles can sometimes attract

Everyone knows that usually, when it comes to charged particles, opposites attract. But in liquids, birds of a feather can flock together. Researchers investigating the long-standing mystery of why like-charged particles in solution can be drawn to each other have found that the nature of the solvent is key. The way that the liquid molecules arrange themselves around the particles can generate enough ‘electrosolvation force’ to overcome electromagnetic repulsion.

Planet-eating stars hint at hidden chaos in the Milky Way

Stellar detectives have identified seven stars that recently gobbled up a rocky planet. The planets seem to have been eaten during their stars’ relatively stable main-sequence period. If this is true, it means these systems have continued to be chaotic long after their formation, with planets disintegrating or falling into their star.

AI helps design antibodies from scratch

For the first time, an artificial intelligence (AI) system has helped researchers to design completely new antibodies. Creating new versions of these immune proteins, which can be used as drugs, is usually a lengthy and costly process. An AI algorithm similar to those of the image-generating tools Midjourney and DALL·E was trained on thousands of real-world structures of antibodies attached to their target proteins. It then churned out thousands of new antibodies that recognize certain bacterial, viral or cancer-related targets.

Hawking’s paradox still puzzles physicists

Physicist Stephen Hawking died six years ago, on 14 March 2018. Fifty years ago, he published a Nature paper with the enigmatic title: Black hole explosions? The paper introduced the concept of ‘Hawking radiation’: the idea that black holes are not truly black because they constantly emit a tiny amount of heat. As Hawking soon realised, this creates a paradox. Hawking radiation doesn’t maintain the details of the original material that went into the hole; therefore, it inexorably erases information from the Universe, contradicting the laws of quantum mechanics. Efforts to solve the conundrum have led to legendary wagers, a theory that wormholes connect the inside of black holes with the outside and the idea that the Universe is a hologram.

Indigenous Australian fire-stick farming began at least 11,000 years ago

Indigenous Australians have been using fire to shape the country’s northern ecosystems for thousands of years. Researchers analysed charcoal that was preserved in the sediment of a flooded sinkhole over the last 150,000 years. They discovered that, around 11,000 years ago, there was a shift to more frequent but less intense fires as a result of Indigenous fire-stick farming. European colonisation mostly brought an end to the practice, which might have contributed to the return of more high-intensity wildfires.

Bumblebees show behaviour previously thought to be unique to humans

Researchers who set up a confusing puzzle box with a sweet reward revealed that bumblebees (Bombus terrestris) can learn skills from others that they could not acquire alone — a behaviour thought to be unique to people. After showing that no lone bee could work out how to solve the puzzle, the scientists painstakingly trained nine bees how to do it. The trained bees became demonstrators for other bees, who watched, learnt and won their reward.

Oldest stone tools in Europe hint at ancient humans’ route there

Stone tools found in western Ukraine date to roughly 1.4 million years ago, making them the oldest known artefacts in Europe made by ancient humans. The findings support the theory that our early relatives — probably of the versatile species Homo erectus — first entered Europe from the east and spread west. The type of tools, and the location where they were found, hint that the first Europeans might have moved westwards along the valleys of the Danube River.

Amphibian nurses its young with ‘milk’

A species of amphibian is the first observed to nourish its young with a milk-like product, which it squirts from the cloaca, a combined rear opening for its reproductive and digestive systems. Siphonops annulatus is a blind, worm-like caecilian that lives underground. Lactation is considered a key characteristic of mammals, but a handful of other animals — including some birds, fish, insects and even spiders — produce nutrient-rich liquid for their offspring.

How heavy is a neutrino?

Physicists gathered this week to compare notes on how to weigh neutrinos, one of the most mysterious of the elementary particles. Currently, only one experiment in the world has a shot at making such a measurement — the massive, Zeppelin-shaped Karlsruhe Tritium Neutrino (KATRIN) detector in Germany. The researchers hope to build scaled-up versions of alternative experimental techniques that could eventually compete with KATRIN, or even improve on it.

How dwarf galaxies lit up the Universe after the Big Bang

Astronomers have used the James Webb Space Telescope to show that faint miniature galaxies swept away a fog of atomic hydrogen in the early Universe — allowing starlight to shine through the cosmos for the first time. Dwarf galaxies roughly 100 times smaller than the Milky Way triggered the process, known as reionisation.

Giant ‘bubble’ in space could be source of powerful cosmic rays

A turbocharged galactic accelerator could produce the Milky Way’s most powerful cosmic rays. The origin of these ultra-fast particles is hard to pin down because they bounce off magnetic fields, so their flight paths are difficult to follow. To get around the problem, researchers measure particles that are produced when cosmic rays hit interstellar gas and that travel in straight lines. One huge gamma-ray-emitting bubble was detected within a star-forming region in the Cygnus constellation.

Supernova mystery solved

The remains of a supernova that revolutionised modern astrophysics has been confirmed as a neutron star. The event, spotted in 1987, was the closest and brightest supernova observed since 1604, giving astronomers the unprecedented view of how stars die. Now the James Webb Space Telescope has peered through the veil of dust left by the explosion and detected ionised argon and sulphur gas, the signature of an ultradense neutron star.

The life and gruesome death of a bog man revealed after 5,000 years

A man who ended up in a Danish bog 5,000 years ago with his skull crushed by a wooden club might have come from far-off northern Scandinavia. Carbon and nitrogen isotope levels in bones and teeth, which can reveal aspects of diet, suggest that ‘Vittrup Man’ had transitioned from a hunter-gatherer lifestyle to farming in his late teens. And genetic analysis shows he was related to hunter-gatherers from what is now Norway and Sweden, not to the farming communities of Denmark.

Stone age wall found at bottom of Baltic Sea ‘may be Europe’s oldest megastructure’

A string of boulders almost a kilometre long, now covered by the Baltic Sea, could be Europe’s oldest human-made megastructure. Researchers say the “pristine” discovery was probably used for hunting the Eurasian reindeer more than 10,000 years ago. Before it was submerged by rising sea levels about 8,500 years ago, hunters might have used the wall to force prey into a bottleneck or a nearby lake.

Mind-reading devices reveal brain’s secrets

Brain–computer interfaces (BCIs) — implanted devices that are powered by thought alone — can restore the ability to move and speak to people with paralysis. They are also overturning assumptions about how the brain is organised. For example, BCI recordings of single-neuron activity have revealed that brain regions have fuzzier boundaries than was thought. Researchers have also started to show how BCI use changes the brain. Over time, users’ brains seem to become more efficient at controlling the device and require fewer neural resources to do the tasks. For now, the scope of BCI research remains limited, with only small clinical trials.