Mars rover finds possible signs of ancient Red Planet life

These tiny ‘leopard spots’, discovered in a rock on Mars by NASA’s Perseverance rover, could be possible signs of microbes that once lived on the red planet. “On Earth, these types of features in rocks are often associated with the fossilised record of microbes living in the subsurface,” says astrobiologist and Perseverance team member David Flannery. Without returning a rock sample to Earth, it will be difficult to further investigate the spots’ origin. “We have zapped that rock with lasers and X-rays and imaged it literally day and night from just about every angle imaginable,” says the rover’s project scientist Ken Farley. “Scientifically, Perseverance has nothing more to give.”

Did complex life start on Snowball Earth?

More than 500 million years ago, the globe was covered in glaciers and sea ice. This Snowball Earth seems hostile to life, yet it was probably during this time that single-celled organisms first evolved into complex, multicellular creatures. One possible answer to this conundrum: when seawater gets colder, it gets more viscous, so individual cells could have started to stick together to move through it more efficiently in search of food. In experiments with modern single-celled green algae, cells living in viscous gels formed coordinated groups to keep swimming.

Heaviest element yet within reach after major breakthrough

Researchers have demonstrated a new way to make superheavy elements, opening the door to creating the heaviest element ever and adding another row to the periodic table. Scientists used a beam of titanium to make a known superheavy element, livermorium — element 116. If they’re able to make elements 119 and 120, as planned after an equipment upgrade, they will be the first documented from the eighth ‘period’. In this row, scientists expect to find atoms with so-far unseen electron configurations.

Mystery oxygen source discovered on the sea floor — bewildering scientists

Something is pumping out large amounts of oxygen at the bottom of the Pacific Ocean, at depths where a lack of sunlight makes photosynthesis impossible. The find has surprised scientists and the source remains a mystery. The oxygen might be generated by metal-rich mineral deposits, or nodules. To researchers’ surprise, they measured voltages of up to 0.95 volts across the surface of the nodules. It is possible that the nodules catalyse the splitting of water into oxygen and hydrogen, but more experiments are needed.

Dogs might have evolved to read our emotions

Centuries of co-evolution seem to have led to dogs being able to sense our emotional states. When dogs were played the sounds of people crying or humming, they appeared more stressed by the sad sounds than by the neutral one. And they’re not just learning from being around us. Pet pigs — who were also raised alongside people but whose species played a very different role in human societies — seemed to find the humming more upsetting.

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As other researchers have previously suggested, this is the result of artificial selection by humans.

Our last common ancestor

The shared forebearer of all life — known as the last universal common ancestor (LUCA) — lived around 4.2 billion years ago, ate carbon dioxide and hydrogen, and produced acetate that might have fed other life. Researchers inferred information about our great-great-grandblob’s genetics and biology by tracing duplicated, lost and mutated genes back up the family tree. LUCA probably possessed an early immune system, too — hinting that it lived in an established ecosystem full of microbes and pathogens.

First fossil chromosomes discovered in freeze-dried mammoth skin

Scientists have discovered intact chromosomes preserved in the skin of a woolly mammoth (Mammuthus primigenius) that met its end some 50,000 years ago — a feat previously thought to be impossible. The team also revealed the spatial organization of the mammoth’s DNA molecules and the active genes in its skin, including one responsible for giving the animal its fuzzy appearance. The study is the first to report the 3D structure of an ancient genome, says molecular archaeologist Ludovic Orlando.

Stars hint at an unusual black hole lurking in our Galaxy

Images taken by the Hubble Space Telescope point to an elusive intermediate-size black hole in the star cluster ω Centauri. Midsize black holes occupy the no-man’s land between the ‘super massive’ ones thought to lie at the centre of most galaxies and much smaller ones that have about as much mass as a single large star. So far, most candidates have turned out to be neutron stars upon closer inspection.

Huge neutrino detector sees first hints of particles from exploding stars

Japan’s Super-Kamiokande observatory is seeing what might be the first hints of neutrinos from exploding stars. Neutrinos are subatomic particles that can come from various cosmic sources; those from inside supernovas could provide information about potentially new physics occurring under extreme conditions. Although the data from Super-K are still too weak to claim a definitive discovery, researchers hope to eventually prove that neutrinos are so stable that those from ancient supernovas are still around.

Ultra-detailed brain map shows neurons that encode words’ meaning

For the first time, individual brain cells have been seen to respond to the essence of words. Researchers recorded the activity of around 300 neurons each in 10 people who had electrodes implanted in their brains to manage epilepsy. Only a few neurons fired for each word when the participants listened to short sentences. Words that fell into similar categories — actions, food or animals — as well as words that could be associated — such as ‘duck’ and ‘egg’ — triggered similar brain activity. To an extent, the researchers could determine what people were hearing by watching their neurons fire.

Denisovans’ survival secrets revealed

The enigmatic ancient humans known as Denisovans hunted marmots, eagles and even hyenas to thrive high on the Tibetan plateau for well over 100,000 years. “It’s at high altitude. It’s cold. It’s not a nice place to be as a hominin,” says archaeologist Frido Welker, one of the researchers who analysed thousands of animal bone fragments from a cave in northern China.

The Milky Way is ‘less weird’ than we thought

Our Galaxy’s core isn't as densely packed with stars as previously estimated, meaning that the Milky Way is similar to other spiral galaxies with around the same mass. Measuring the Galaxy’s size and shape is tricky — it’s like working out how big a city is while standing on a street corner. Instead of extrapolating from the distribution of stars in our immediate galactic surroundings, scientists measured the locations and distances of almost a quarter of a million massive red giants. These old stars are good markers of visible matter in the Galaxy, and their near-infrared light can pass through the interstellar dust that obscures other wavelengths.

Five new ways to catch gravitational waves

Scientists are developing ways to spot those ripples in space-time that are invisible to current gravitational-wave-hunting facilities such as LIGO.

1. Ultra-long waves could be detected over many years by measuring the distance between Earth and stars called pulsars.
2. Telescopes are searching for patterns in the cosmic microwave background that would have been imprinted by gravitational waves in the early universe.
3. Observing atoms as they drop down a 1km-tall pipe could reveal waves coming from black hole collisions.
4. Desktop detectors for speculative high-frequency waves could reveal exotic physics right after the Big Bang.
5. A radical idea for spotting gravity waves involves putting a diamond crystal into quantum superposition — something that has never been demonstrated.

‘Fantastic’ particle could be most energetic neutrino ever detected

An observatory in the depths of the Mediterranean Sea has spotted what could be the most energetic neutrino ever detected — “a fantastic event”, says physicist Francis Halzen. Neutrinos are tiny subatomic particles that travel at nearly the speed of light and are thought to come from cataclysmic cosmic events, such as a growth spurt of a supermassive black hole. For now, the team is staying quiet about the direction the neutrino came from to avoid tipping off competitors about its origin.

A common misunderstanding about wave-particle duality

It’s an all-too-common misconception to think of light, electrons and other quantum entities as shape-shifters that can sometimes be waves, and other times particles, says science writer Philip Ball. Recent experiments that were widely reported as showing ‘particles morphing into waves’ reveal the problems of using classical concepts to describe quantum mechanics, he explains. “Wave-particle duality is not a property of the quantum world, but a flawed classical analogy for it.”

Astronomers detect sudden awakening of black hole 1m times mass of sun

A black hole that’s more than one million times more massive than the Sun has suddenly woken up at the centre of a distant galaxy, dubbed SDSS1335+0728. The stirring black hole might be the culprit behind the galaxy’s unusual brightening, which has had scientists scratching their heads since 2019. The surge in light output is probably due to the presence of an active galactic nucleus, which occurs when a black hole begins chewing through the material that surrounds it.

Measuring the forces that sculpt embryos

Scientists are finding new ways to measure how squeezing, stretching, pushing and pulling forces shape the development of every tissue in the body. Tiny oil-encapsulated droplets can sense stresses inside live embryos and optical tweezers can push and pull cell membranes or organelles. Some researchers are developing contact-free alternatives such as the ‘foambryo’ algorithm, which models embryos as foams of bubble-like cells.

How the ‘mind’s eye’ calls up visual memories from the brain

Vivid memories that flash into the mind’s eye might be made in the primary visual cortex, the same area of the brain that processes raw visual input from the eyes. A study in monkeys suggests that neurons there display a different activity pattern when images are conjured up from memory compared with real-time vision. Some researchers say that other areas, such as the prefrontal cortex, are more likely to be the seat of the ‘mind’s eye’.

Do elephants have names for each other?

Elephants seem to use proper names to address their fellows. Scientists used machine learning to analyse 469 deep rumbles made by wild female African savannah elephants (Loxodonta africana) and their families in Kenya. They found patterns that indicate that calls are specific to individuals. The researchers also played recorded calls to elephants out in the field and watched how the animals responded.

Fire pits offer glimpse into Neanderthal life

Ancient hearths reveal that generations of Neanderthals regularly visited a rugged river valley in Spain over a period of around 200 years. Previous work estimated that Homo neanderthalensis made these fires around 52,000 years ago — plus or minus a few thousand years. Researchers dramatically narrowed down this timeframe by analysing traces of Earth’s changing magnetic field preserved in the fire pits’ minerals. The oldest and youngest of the hearths were last lit at least 200 years apart, with decades-long intervals between the use of different hearths.

Physicists coax molecules into exotic quantum state — ending decades-long quest

A decades-long quest to create a Bose–Einstein condensate from molecules is finally over. Physicists cooled sodium-caesium molecules until they were almost stationary — which, thanks to Heisenberg’s uncertainty principle, meant their positions were so uncertain that they became indistinguishable and formed a single gigantic quantum state. Physicists have forced atoms into this bizarre state of matter since 1995, but molecules are much harder to cool. The key was using microwave fields to keep heat-generating collisions between molecules under control.

Biggest genome ever found

A species of fork fern, Tmesipteris oblanceolata, has the biggest genome ever recorded. It contains 160 billion base pairs — 11 billion more than the previous record holder, the flowering plant Paris japonica, and 50 times more than the human genome. It’s not known why the fern evolved that way, or how it accesses the relatively small proportion of DNA that is actually useful.

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.