Last images from DART as it crashed into an asteroid

NASA smashed a spacecraft into an asteroid on purpose on Monday, and we all got a ringside seat. The Double Asteroid Redirection Test (DART) probe rammed into the harmless asteroid Dimorphos to test whether humanity could reroute a dangerous asteroid heading for Earth. DART took pictures every second as it approached the space rock. Telescopes on Earth watched the collision. And a tiny satellite flew alongside and photographed the impact, which took place 11 million kilometres from Earth. Studying its shots of the plume of debris that was ejected from Dimorphos will help scientists to understand exactly how the impact unfolded.

China’s Mars rover finds hints of catastrophic floods

China’s Zhurong rover has peered under the surface of Mars — down to 100 metres — and has found evidence of two huge floods that shaped the landscape. Since May last year, Zhurong has been exploring Utopia Planitia, in Mars’s northern hemisphere. Images from the rover’s ground-penetrating radar found layered patterns under the surface, which the authors suggest are made of sedimentary rocks carried in by two major floods around 3 billion and 1.6 billion years ago. But other scientists say that, although radar is good at detecting layers of subsurface material, it’s less proficient at identifying what layers are made of.

NASA’s Mars rover makes ‘fantastic’ find in search for past life

Since July, NASA’s Perseverance rover has drilled and collected four slim cores of sedimentary rock, formed in what was once a river delta on Mars. They are the first of this type of rock to be gathered on another world — and scientists are excited because at least two of the cores probably contain organic compounds, which, on Earth, are often associated with living things. If all goes well, the samples will be the first ever returned from Mars. They will be picked up by another spacecraft and brought back to Earth no earlier than 2033.

‘Lunar wobble’ influences mangrove growth

Long-term fluctuations in the Moon’s orbit — known as the lunar wobble — could influence mangrove canopy growth. Researchers in Australia used high-resolution satellite images to measure mangrove canopy across the continent between 1987 and 2020. They found that the wobble, which pulls low tides lower and high tides higher in a cyclic pattern that lasts about 18 years, was a major factor in the expansion and contraction of mangrove growth. Depending on the phase of wobble, mangrove ecosystems get less water — resulting in thinner canopy cover — or higher tides that increase growth. Mangroves are natural carbon sinks, so the findings could help to better assess how much carbon they will store over time.

Genes May Explain HowThis Jellyfish Can Live Forever

The tiny translucent jellyfish Turritopsis dohrnii can revert to an immature polyp state and revive itself again and again — effectively making it immortal. Researchers have now sequenced the jellyfish’s genome and studied the genes involved in its rejuvenation. They found that genes associated with DNA storage were highly expressed in adult jellyfish, but reduced as the animals transformed into polyps. However, genes linked to pluripotency, or the ability of cells to turn into any cell type, were increasingly expressed as the jellyfish reverted.

Milky Way spirals boost Earth crust formation

Earth’s crust builds up faster when the Solar System surfs through one of four spiral arms of the Milky Way. Researchers measured the decay of uranium in the ancient continental crust in Greenland and Australia to study how it formed between 2.8 and 3.8 billion years ago. They found that, every 200 million years or so — in tune with Earth passing through the Milky Way — the rate of crustal production increased. One explanation could be that denser areas of the galaxy dislodge more comets from the Oort cloud, which rain down on Earth, melting the crust and causing more magma to bubble up and congeal.

Did this gene give modern human brains their edge?

Researchers have pinpointed a fateful genetic mutation that might have contributed to a cognitive advantage for modern humans over Neanderthals. Tests in the laboratory suggest that a single change in the gene TKTL1 ultimately causes the brain to develop more neurons. The Neanderthal version of TKTL1 still exists in some modern humans, although it’s very rare and it’s unknown whether it causes any disease or cognitive differences.

Blogger Comments:

Neanderthals had the larger brains, and all 'out of Africa' humans have Neanderthal ancestry. 

Webb telescope spots CO2 on exoplanet for first time

The James Webb Space Telescope has captured the first unambiguous evidence of carbon dioxide in the atmosphere of a planet outside the Solar System. The telescope gleaned information about the composition of the gas giant WASP-39b as it moved across the face of its star. Starlight shone through the planet’s atmosphere, where various molecules absorbed specific wavelengths of infrared light, creating the telltale absorption spectrum in the image above. The result has bolstered confidence that Webb is going to be revolutionary for exoplanet research.

‘Levitating’ nanoparticles could push the limits of quantum entanglement

Physicists have suspended tiny glass spheres in a vacuum and made them interact with one another at close distance. The ‘levitating’ nanoparticles can be manipulated with exquisite precision, offering the tantalising prospect of probing quantum physics at a macroscopic scale. For example, if the particles can be slowed to their quantum ground state (as cold as they can get), it could become possible to put them into a state of quantum entanglement, meaning that some of their measurable properties — in this case, their positions — are more strongly correlated than would be allowed by the laws of classical, non-quantum physics.

Seven-million-year-old femur suggests Sahelanthropus tchadensis walked upright

An ancient human relative, Sahelanthropus tchadensis, might have walked on two legs seven million years ago. S. tchadensis could be the earliest known member of the hominin lineage, the evolutionary branch that includes the common ancestor of humans and chimpanzees and ends with modern humans. The theory is based on a battered fossil leg bone that was discovered in Chad more than 20 years ago. But some scientists are not convinced that the femur’s traits prove the creature stood tall.

Webb sees most distant star ever observed

The James Webb Space Telescope has imaged the most distant star ever discovered, which is 8.5 million parsecs away. The star was first identified by the Hubble Space Telescope earlier this year. WHL0137-LS — or ‘Earendel’, meaning ‘morning star’ in old English — is thought to have formed just 900 million years after the Big Bang. It is visible thanks to gravitational lensing: the massive Sunrise Arc galaxy cluster in its foreground warps spacetime so much that the star is magnified thousands of times.

Huge megalithic complex of more than 500 standing stones discovered in Spain

A huge complex of more than 500 standing stones has been discovered in southern Spain during an archæological survey of a plot of land earmarked for an avocado plantation. The oldest of the megaliths — which include stone circles, mounds and tombs — were probably placed during the sixth or fifth millennium BC.

Megalodon shark was longer than a bus

A 3D model of a colossal shark that roamed the oceans millions of years ago suggests that the beast was 16 metres long and could have eaten a whale in just a few bites. Few megalodon fossils exist, but researchers were able to create the digital model using a rare collection of vertebrae and teeth, as well as scans of modern great white sharks (Carcharodon carcharias). They calculated that the ancient creature weighed around 70 tons — as much as ten elephants— and that its open jaw stretched to 2 metres wide.

Notorious dark-matter signal could be due to analysis error

Physicists have shown that an underground experiment in South Korea can ‘see’ dark matter streaming through Earth — or not, depending on how its data are sliced. The results cast further doubt on a decades-old claim that another experiment has been detecting the mysterious substance.

AI predicts shape of nearly every known protein

Determining the 3D shape of almost any protein known to science will soon be as simple as typing in an internet search. Researchers have used the revolutionary artificial-intelligence (AI) network AlphaFold to predict the structures of some 200 million proteins from one million species, covering nearly every known protein on the planet. The data will be uploaded to a free database.

Molecular motor is ‘DNA origami’ milestone

Physicists have built a molecular-scale motor entirely from DNA strands, and used it to store energy by winding up a DNA ‘spring’. The tiny machine gains energy from Brownian motion — the constant random argy-bargy of molecules in a medium. The machine turns like the ratchet wheel in a clock, winding a string of DNA like a spiral spring.

Ear fossils hint at origin of warm-blooded mammals

Fossilised inner-ear canals suggest that the moment mammals evolved to be warm-blooded — the timing of which is highly contested — occurred around 230 million to 200 million years ago. A team of researchers hypothesised that hotter, more active bodies would have less viscous fluid in their vestibular system, which maintains balance and spatial orientation — and the inner ear’s shape would adapt in turn. After calibrating their understanding on the basis of 50 living vertebrate species, they analysed the inner ear canals of 56 extinct synapsid species — the reptile-like ancestors of mammals — and found that the shape of the canals had changed abruptly in the Late Triassic period.

Mass and Angular Momentum, Left Ambiguous by Einstein, Get Defined

In 1979, Nobel-prizewinning physicist Roger Penrose said that the two biggest unsolved problems in general relativity concerned mass and angular momentum (a measure of rotational motion). Both those properties, which are easy enough to understand in day-to-day life, spiral out of mathematical control when an object interacts with the curvy-wurvy effects of space-time within a finite region. Now both problems have been solved, thanks to a culmination of decades of work.

Hoatzin could reshape avian taxonomy

Hoatzins (Opisthocomus hoazin) present an evolutionary enigma — one analysis of their DNA suggests that the birds’ closest relatives are cranes and shorebirds, and another found that they are closely related to a group that includes tiny, hovering birds, such as hummingbirds. The riddle is forcing biologists to consider whether to rethink the shape of the standard ‘tree of life’ for modern birds.

Root-cropping behaviour in gophers may represent a kind of husbandry

Gophers graze on roots that grow into their large network of tunnels, which some researchers say could be the first evidence of a non-human mammal engaging in farming. Scientists installed cameras in trenches that they dug around tunnels used by southeastern pocket gophers (Geomys pinetis) in Florida. The roots of above-ground grasses and nettles quickly filled the tunnels that the gophers couldn’t access, but remained short in those they could. The animals nibbled on the roots to nourish themselves and stimulate root regrowth, and dropped waste throughout the network to fertilise the soil — effectively cultivating the crop. Other researchers say the practice can’t be described as farming because the gophers don’t plant or distribute their crops as do humans and other creatures, such as fungus-growing ants.

Five things we don’t know about the Higgs boson

1. So far, scientists have determined that the boson’s properties — such as its interaction strength — match those predicted by the standard model, but with an uncertainty of around 10%. This is not good enough to show the subtle differences predicted by new physics theories.
2. Physicists have seen the Higgs boson decay into only the heaviest matter particles, such as the bottom quark. They now want to check whether it interacts in the same way with particles from lighter families, known as generations.
3. The Higgs boson has mass, so it should interact with itself, and the rate of this self-interaction is crucial to understanding the Universe. But such events — for example, the decay of an energetic Higgs boson to two less-energetic ones — are extremely rare and haven’t been conclusively observed yet.
4. Physicists want to know the lifetime of the Higgs — how long, on average, it sticks around before decaying to other particles — because any deviation from predictions could point to interactions with unknown particles, such as those that make up dark matter.
5. Some theories that extend the standard model predict that the Higgs boson is made up of other particles, or that there are different types of Higgs boson. Future observations could provide evidence if any of these exotic predictions are true.

Muon magnetism update

Last year, an experiment suggested that the muon — a subatomic particle similar to an electron — had inexplicably strong magnetism, possibly breaking a decades-long streak of victories for the leading theory of particle physics, known as the standard model. Now, revised calculations by several groups suggest that the theory’s prediction of muon magnetism might not be too far from the experimental prediction after all. By narrowing the gap, the latest predictions might make it easier to resolve the discrepancy between theory and experiment.

Ice Age wolf genomes point to dog origins

Modern dogs probably evolved in eastern Eurasia — and might have been domesticated more than once. Researchers analysed 72 ancient wolf (Canis lupus) genomes spanning the last 100,000 years. They found that early dogs from northeastern Europe, Siberia and North America are closely related to ancient wolves from eastern Asia. However, some dogs from western Europe and Africa seem to have a genetic link to ancient wolves that lived farther west.

Mastodon tusk reveals life of roaming

Chemical signatures inscribed in an ancient tusk tell a mastodon’s life story — from his adolescent years to his premature death around 13,200 years ago. Researchers matched the chemical signatures in the tusks of an American mastodon (Mammut americanum) with those from his home range in what is now Indiana. They found that, as an adult, he travelled to mastodon mating grounds every year in the spring and summer. It was there, at 34 years of age, that he met his end, probably from a skull puncture during a battle with another bull.

How the giraffe got its neck

A newly described species of giraffoid that lived millions of years ago in China suggests how the giraffe might have got its long neck. Discokeryx xiezhi, named after a mythical unicorn-like creature, had a thick headpiece optimised for high-speed, head-bashing fights. Its discovery adds more weight to the theory that giraffes evolved longer necks for sexual competition, with male giraffes engaging in violent neck-swinging fights and longer necks attracting mates.

How a special immune system protects grey matter

Researchers once thought that the brain was walled off from the rest of the body’s immune system, but an exciting picture is emerging of the brain as a unique immunological ecosystem. The brain’s border control actually does allow immune cells from the body into the fluid-filled membranes that surround the organ. Special immune cells produced in the skull’s bone marrow could be gentler than normal immune cells. Researchers are exploring how these and other kinds of immune cells in the brain play a role in fighting diseases and could be harnessed in treatments.

Physicists trace the rise in entropy to quantum information

The second law of thermodynamics expresses a fundamental truth about the Universe — that entropy, a measure of disorder, will always increase. Now some physicists are proposing that the law comes about because of quantum effects such as entanglement. In this telling, an increase in entropy is not just the most likely outcome of change, it is a logical consequence of quantum behaviour.

Black-hole image sheds light on Milky Way mysteries

The first image of our Galaxy’s supermassive black hole, released earlier this month, has already begun to explain some enduring mysteries about the heart of the Milky Way. Alongside other evidence, the results suggest that Sagittarius A* is sucking in matter at a slow pace, making it unusually dim compared with the central black holes of other galaxies. The observations also hint that Sagittarius A* could have been spectacularly active only a few million years ago. And there are fresh questions about some of the largest structures seen in and around the Milky Way.

‘Mind blowing’ ancient settlements uncovered in the Amazon

The southwest corner of the Amazon Basin was once the site of complex urban settlements built by ancient civilisations. Researchers used a laser remote-sensing technology called lidar to map land inhabited by the Casarabe culture, which existed around AD 500 to 1400 in what is now Bolivia. Observations from the air reveal that Casarabe people lived in densely populated centres, featuring 22-metre-tall earthen pyramids, that were encircled by kilometres of elevated roadways. They also had large water-management infrastructure made of canals and reservoirs.

Can galaxies form without dark matter?

Scientists think that galaxies cannot form without the gravitational pull of dark matter. But astronomers might have observed a line of 11 galaxies that don’t contain any dark matter, which could all have been created in an ancient collision. Some are unconvinced that the claim is much more than a hypothesis.

Ancient tooth suggests Denisovans ventured far beyond Siberia

A fossilised tooth unearthed in a cave in northern Laos might have belonged to a young Denisovan girl who died between 164,000 and 131,000 years ago. If confirmed, it would be the first fossil evidence that Denisovans — an extinct hominin species that co-existed with Neanderthals and modern humans — lived in southeast Asia. The molar would be only the second Denisovan fossil found outside Siberia, but millions of people with Asian, Oceanian or Pacific Islander ancestry carry traces of Denisovan DNA.

Ancient DNA maps ‘dawn of farming’

Europe’s first farming populations descend mostly from farmers in the Anatolian peninsula, in what is now Turkey. And the ancient Anatolian farmers descended from repeated mixing between distinct hunter-gather groups from Europe and the Middle East. A pair of ancient-DNA studies — including one of the largest assemblages of ancient human genomes yet published — reveal finer details of the dawn of farming, thanks to ‘high coverage’, or high-quality, genomes — a rarity in ancient-genomics work.

Origin of life theory involving RNA–protein hybrid gets new support

Chemists say they have solved a crucial problem in a theory of life’s beginnings, by demonstrating that RNA molecules can link short chains of amino acids together. This might have allowed for ever-more complex RNAs, proteins and combinations of the two — a possible path to the chemistry of life that we know today. The findings support a variation on the ‘RNA world’ hypothesis, which proposes that, before DNA evolved, the chemical ancestors of biological life were based on RNA.

Black hole at the centre of our Galaxy imaged for the first time

Below is Sagittarius A* — the black hole at the centre of our galaxy. It’s only the second time a black hole has been directly imaged. Like the first such image — of the supermassive black hole at the centre of a nearby galaxy called M87, in 2019 — astronomers created the picture by processing radio-wave observations that are invisible to the human eye. The long-awaited results were obtained from data collected in 2017 by the Event Horizon Telescope, a global network of radio observatories. Sagittarius A* seems to be rotating anticlockwise along an axis that roughly points along the line of sight to Earth.

Bats buzz like hornets to scare off owl predators

Some bats can imitate the sound of buzzing hornets to scare off owls — the first documented case of a mammal mimicking an insect to deter predators. Researchers compared the sound structure of buzzing by the European hornet (Vespa crabro) to that of the distress call of greater mouse-eared bats (Myotis myotis). At most frequencies, the two sounds were not dramatically similar, but they were when the bat’s call was stripped down to include only frequencies that owls can hear.

A ‘galaxy’ is unmasked as a pulsar

An object that astronomers thought was a distant galaxy is actually the brightest extra-galactic pulsar ever seen. Pulsars are among the few celestial objects that emit circular polarised light, so scientists used a computer program that works like sunglasses: it filters out other kinds of light. The team could then spot the ‘hidden’ pulsar.

Fossil hints at colourful pterosaur feathers

A remarkable fossil reveals that pterosaurs might have been covered in brightly coloured feathers. The exquisitely preserved Tupandactylus imperator shows the soft tissues of the animal’s crest and filament structures that suggest that it had true feathers. The fossil also preserves melanosomes: tiny organelles that contain melanin and cause much of the colouring in features and skin. Researchers found different types of melanosome, suggesting that it sported various colours — and that its feathers weren’t just to keep it warm.

Blind cave fish have regional accents

In the underground caves of north-eastern Mexico, groups of blind fish that communicate using clicks seem to be developing cave-specific accents. Researchers studying the Mexican tetra (Astyanax mexicanus) analysed hours of fish chatter in six caves spread across the three mountain ranges. They noticed significant differences: clicks were relatively high-pitched in one cave, and deep and booming in another, for example. The linguistic split could eventually contribute to ongoing speciation among the fish.

Simulation hints at how climate shaped human migration

A record-breaking simulation of the past two million years of Earth’s climate provides evidence that temperature and other planetary conditions influenced early human migration — and possibly contributed to the emergence of the modern-day human species around 300,000 years ago.

An interstellar object exploded over Earth in 2014

Declassified US government data confirm that a small meteorite that blazed through the skies over Papua New Guinea in 2014 came from far beyond our Solar System. In 2019, researchers argued that the object’s high speed and trajectory suggested that it originated from another star system. But the study was never peer-reviewed because the data needed to verify the calculations were classified. The confirmation by US government officials makes the meteorite the first interstellar object to be detected in our Solar System, spurring scientists to consider a search for shards of the object that might have settled on the sea floor.

W boson’s surprise mass threatens to upend the standard model

Physicists analysing data from a long-defunct experiment have found that the W boson — a fundamental particle that carries the weak nuclear force — is notably heavier than theory predicts. Although the difference between the theoretical prediction and experimental value is only 0.09%, it is significantly larger than the result’s error margins, which are less than 0.01%. The finding also disagrees with some other measurements of the mass. If it is confirmed by other experiments, it could be the first major breach in the standard model of particle physics, a theory that has been spectacularly successful since it was introduced in the 1970s.

Can mushrooms ‘speak’?

Researchers who tapped into the network that connects fungi say that its patterns of electrical signals resemble human speech. Previous studies have suggested that fungi use electrical signals to communicate and process information across tiny connective threads called mycelium. In the new study, researchers inserted tiny electrodes into substrates colonised by four species of fungi. They found that spikes of electrical activity often clustered into groups that resembled vocabularies of up to 50 words and could be similar to human language. But some researchers are sceptical.

Blogger Comments:

Although this is unlikely to be evidence of a semiotic system, let alone a language, it may well be a precursor to semiotic systems, where what is exchanged is social value, rather than symbolic value. Such systems, previously thought to be exclusive to animals, have more recently been identified in some plants.

Mystery warriors made the fastest migration in ancient history

Around 1,500 years ago, horse-riding warriors known as the Avars appeared in southeastern Europe seemingly out of nowhere and established an empire lasting more than 200 years. Now, DNA evidence suggests that they crossed a continent in the span of a decade or two. Human remains from Avar tombs in what is now Hungary closely match those from an individual buried just a few decades earlier in what is now eastern Mongolia — almost 7,000 kilometres away.

Scientists classify manatee vocalisations

Researchers listened to seven years of manatee (Trichechus manatus latirostris) chat to learn how the gentle, solitary grazers communicate. Almost all of the creatures’ vocalisations fall into three categories: a high squeak used between mother and calf, a lower squeak that indicated stress and a squeal recorded during “cavorting” and “frisky behaviour”.

Bizarre space circle captured in unprecedented detail

Astronomers have captured a rare image of ‘odd radio circles’, rare space objects made up of gigantic rings of radio waves. Only five of these massive balls of radio waves have ever been spotted, with most containing a galaxy at their centre. Researchers have proposed three theories to explain their origin: they are created from shock waves, radio jets or starbursts in the centre of their galaxies.

Liquid metal, ruby and sapphire could rain down on huge exoplanet

A hot, giant exoplanet, called WASP-121b, could experience ruby and sapphire rain. Astronomers developed a three-dimensional model of the planet based on observations taken from a spectroscopic camera aboard the Hubble Space Telescope. The exoplanet has a hot day side that always faces its star, and whips around in an orbit of just 30 hours. Winds could be blowing vapourised titanium and aluminium from the hot side to the night side, where it rains down as droplets of liquid metal, ruby and sapphire.

A Deepening Crisis Forces Physicists to Rethink Structure of Nature’s Laws

Particle physicists, who study nature’s fundamental building blocks, are in crisis. The relationship between the Higgs boson and phenomena at the highest energy scales — those associated with the quantum nature of gravity, black holes and the Big Bang — just doesn’t feel right. The equations require extreme fine-tuning — of a type that physicists dub ‘unnatural’ — to work out in a way that reflects observations. Some physicists think this failure of ‘naturalness’ signals the breakdown of reductionism — that the laws of physics at big scales emerge from those at smaller scales.

Blogger Comments:

This misunderstands reductionism. Reductionism is the misinterpretation of a compositional hierarchy as reducing to its lowest level, as when physicists say nonsense like 'we are nothing but elementary particles'.

Tyrannosaurus rex may have been three species

Tyrannosaurus rex might not have been one species, but three. Palæontologists studying 37 T. rex specimens say there is too much variation in their ‘stout build’ and teeth to be a single species. Instead, they propose that fossils found in lower layers of rock are probably from a species they call Tyrannosaurus imperator, and slender-boned specimens are likely from a creature they’ve named Tyrannosaurus regina. The work has prompted widespread discussion, but many palæontologists are not convinced.

Largest bacterium ever discovered has an unexpectedly complex cell

A newly discovered bacterium, Thiomargarita magnifica, challenges the definition of a microbe: its filament-like single cell is up to 2 centimetres long. T. magnifica achieves its unprecedented size by having unique cellular features: two membrane sacs. One is filled with its genetic material; the other, which is much larger, helps to keep its cellular contents pressed up against its outer cell wall so that the molecules it needs can diffuse in and out. Researchers have dubbed these sacs ‘pepins’ — inspired by the pips in fruit — and note that they blur the line between single-celled prokaryotes and eukaryotes (the group that includes humans), which pack their DNA into a nucleus.

Largest Jurassic pterosaur discovered

The largest pterosaur fossil from the Jurassic Period has been uncovered in Scotland. The new species of flying reptile, Dearc sgiathanach, lived about 170 million years ago and had a wingspan of 2.5 metres — roughly the size of an albatross. Pterosaurs evolved 230 million years ago as small reptiles and eventually grew to be massive creatures with 12-metre wingspans by the Cretaceous Period, 145 million years ago. The new fossil helps to fill a gap in this dinosaur’s history because pterosaur fossils from the Middle Jurassic are very rare.

How light is a neutrino?

Physicists are closer than ever to nailing down the mass of the elusive neutrino. A team at the Karlsruhe Tritium Neutrino (KATRIN) experiment in Germany found that neutrinos have a maximum mass of 0.8 electron volts. Researchers have long had indirect evidence that these mysterious particles should be lighter than 1 eV, but this is the first time that this has been shown in a direct measurement. The experiment has so far been able to put only an upper bound on the mass. But researchers might be able to make a definite measurement once it finishes collecting data in 2024.

Earth-like planet spotted orbiting Sun’s closest star

Astronomers have discovered a third planet orbiting Proxima Centauri, the star closest to the Sun. Called Proxima Centauri d, the newly spotted world is probably smaller than Earth, and could have oceans of liquid water.