Wood-eating clams use their feces to dominate their habitat

Deep beneath the waves, tiny clams with shells usually about as big as a pea bore into pieces of sunken wood. The wood is food for them, as well as a home. These rare, scattered, sunken pieces of wood support miniature ecosystems where different wood-boring clam species can live in harmony for years. But in a new paper in Marine Biodiversity, researchers found that one group of wood-boring clams has evolved a unique way to get the wood all for itself: building chimneys made of poop.

"There are two challenges every sea creature has to face: getting pure water in, so you can get oxygen to your gills, and getting rid of your waste. Because nobody wants to live in their poop. But here are these clams living with theirs, and actually thriving," says Janet Voight, Associate Curator of invertebrate zoology at the Field Museum and the study's lead author.

Scientists can put wood on the seafloor, return months or even years later, and recover it with "an amazing array of animals," says Voight; other times wood that has been submerged for the same amount of time comes up so gnawed and bored-through that you can crumble it in your hand. This difference was a mystery, and Voight wanted to know why.

She took stock of the wood-boring clam species present in reports of sunken wood from all over the world, and she noticed a pattern. "There are six main branches in the wood-boring clam family tree, and every woodfall that was bored so heavily it was crushable by hand turned out to have been bored by a species from the same single branch of that family tree," says Voight. She says she was surprised by this finding -- "that's not supposed to happen, you just assume that all wood-boring clam species, which tend to look pretty similar, bore into wood the same way. And yet, here's one group that's doing something totally different."

Scientists had suggested that the extra-chewed-up wood was due to lots of larvae happening to be present nearby, or warmer water temperatures, but it turns out, the very nature of the clams may be responsible. Voight noted all of these extra-efficient, related species have a common trait where the sun don't shine. As the clams dig and move into their boreholes in the wood, they fill the space around them inside the holes with their own feces.

"They don't do it on purpose, their anatomy makes them do it," says Voight. "When these clams bore into wood, their little shell does the boring." Meanwhile, the clams' siphons, tubular appendages for taking in water to get oxygen and expelling waste, stick out behind them. "In most wood-boring clams, these two "in and out" siphons are equal in length and stick out into the water column," says Voight. "But in these related hyper-nasty borers, the siphon for expelling de-oxygenated water and feces is short; it stays inside the borehole in the wood. As a result, says Voight, "they poop in their borehole. They just have to, unless they really, really push." The waste stays right there with the clam, forming a chimney that wraps around the siphon.

That animals would evolve an anatomy that keeps them in such close contact with their own waste, is surprising, says Voight: "It sure isn't very hygienic, and yet they show no evidence of immune problems. They're healthy, they're clearly going to town on the wood. So why did they evolve this way?"

She and her colleagues hypothesized that these fecal chimneys might cue larval settlement: that their free-floating larvae might be able to detect the poop and make their way to it to make a home alongside members of their own species.

But that still leaves the problem: even if a poop chimney serves as a beacon for other members of their species to join them on their wood, how can these individuals survive as more and more larvae settle and the environment becomes filthier and oxygen becomes less available?

"This group of species of clam has been shown in previous studies to be unusually tolerant of low oxygen," says Voight. They also have additional adaptations, like a mucosal lining of their fecal chimneys, and a substance like hemoglobin in their blood that picks up more oxygen; both may reduce the risk of sulfide poisoning from the waste. Taken together, these adaptations allow these speciesto survive in conditions that would make non-related wood-boring clams sick. The end result is more wood for the chimney-producing species to eat, live in, and for their offspring to settle on, unbothered by competitors.

Beyond just solving the mystery of the gross chewed-up wood with an even grosser solution, Voight says that the study illustrates the importance of looking at ecology with an understanding of how different species are related to each other.

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Marsquake!

The largest earthquake ever detected on Mars has revealed layers in its crust that could indicate past collision with a massive object, such as a meteoroid. Previous data has suggested the past occurrence of a large impact, and the findings offer evidence that might support this hypothesis.

The research, led by UCLA planetary scientists and published in two papers in Geophysical Research Letters, could also indicate that alternating layers of volcanic and sedimentary rocks lie beneath the surface.

The 4.7 magnitude earthquake, or marsquake, happened in May 2022 and lasted more than four hours, releasing five times more energy than any previously recorded quake. Though moderate by Earth standards, the temblor was nonetheless powerful enough to send seismic surface waves completely around the planet's circumference, the first time this phenomenon has been observed on Mars.

The readings were taken from InSight, which landed on Mars in 2018. InSight is the first outer space seismometer to study in-depth the "inner space" of Mars: its crust, mantle and core.

"The seismometer aboard the InSight lander has recorded thousands of marsquakes but never one this large, and it took over three years after landing to record it," said corresponding author Caroline Beghein, a professor of Earth, planetary and space sciences. "This quake generated different kinds of waves, including two types of waves trapped near the surface. Only one of those two has been observed on Mars before, after two impact events, never during a marsquake."

Mapping the seismic activity, the location and frequency of impacts on Mars and the interior structure is important for future missions to the red planet as it will inform scientists and engineers where and how to build structures to ensure the safety of future human explorers.

As on Earth, studying how seismic waves travel through rocks can give scientists clues about the temperature and composition of the planet below the surface that help inform the search for underground water or magma. It also helps scientists understand the past forces that shaped the planet.

Beghein's group combined measurements from two types of surface waves, called Love and Rayleigh waves, to infer the speed of underground shear-waves, which travel horizontally and move rocks perpendicular to the direction of wave propagation. This is the first time Love waves have been observed in conjunction with Rayleigh waves on Mars.

The measurements showed that the shear-waves move faster in the crust when rocks between 10 and 25 kilometers underground oscillate in a direction almost parallel to the planet surface than if the rocks vibrate in the vertical direction.

"This wave speed information is related to deformations inside the crust," Beghein said. "Alternating volcanic rocks and sedimentary layers, which were deposited long ago, or a very large impact, such as a meteoroid, most likely account for the seismic wave measurements we observed."

These data also enabled Jiaqi Li, a UCLA postdoctoral researcher in Beghein's group, to learn that shear-waves move faster in the Martian southern highland areas than in the northern lowlands. The northern hemisphere of Mars has a lower elevation and is covered with more craters than the southern hemisphere. A large impact in the lowlands has been the prevalent theory to explain the origin of this difference.

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Whales could be a valuable carbon sink, say scientists

Nature-based solutions to fight climate change take a holistic approach that promotes biodiversity and ecosystem preservation. While many efforts have focused on planting trees or restoring wetlands, researchers publishing in Trends in Ecology and Evolution on December 15 advocate for the importance of understanding the carbon sequestration potential of the planet's largest animals -- whales. In their paper, the researchers explore how these marine giants can influence the amount of carbon in our air and waters and potentially contribute to the overall reduction of atmospheric carbon dioxide.

"Understanding the role of whales in the carbon cycle is a dynamic and emerging field that may benefit both marine conservation and climate-change strategies," write the authors, led by Heidi Pearson, a biologist from the University of Alaska Southeast. "This will require interdisciplinary collaboration between marine ecologists, oceanographers, biogeochemists, carbon-cycle modelers, and economists."

Whales can weigh up to 150 tons, live over 100 years, and be the size of large airplanes. Like all living things, their hefty biomass is composed largely of carbon and they make up one of the largest living carbon pools in the pelagic ocean, part of the marine system that is responsible for storing 22% of Earth's total carbon.

"Their size and longevity allow whales to exert strong effects on the carbon cycle by storing carbon more effectively than small animals, ingesting extreme quantities of prey, and producing large volumes of waste products," write the authors. "Considering that baleen whales have some of the longest migrations on the planet, they potentially influence nutrient dynamics and carbon cycling over ocean-basin scales."

Whales consume up to 4% of their massive body weight in krill and photosynthetic plankton every day. For the blue whale, this equates to nearly 8,000 pounds. When they finish digesting their food, their excrement is rich in important nutrients that help these krill and plankton flourish, aiding in increased photosynthesis and carbon storage from the atmosphere.

A blue whale can live up to 90 years. When they die and their bodies fall to the seafloor, the carbon they contain is transferred to the deep sea as they decay. This supplements the biological carbon pump, where nutrients and chemicals are exchanged between the ocean and the atmosphere through complex biogeochemical pathways. Commercial hunting, the largest source of population decline, has decreased whale populations by 81%, with unknown effects on biological carbon pump.

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Astronomers find that two exoplanets may be mostly water

A team led by UdeM astronomers has found evidence that two exoplanets orbiting a red dwarf star are "water worlds," planets where water makes up a large fraction of the volume. These worlds, located in a planetary system 218 light-years away in the constellation Lyra, are unlike any planets found in our solar system.

The team, led by PhD student Caroline Piaulet of the Trottier Institute for Research on Exoplanets (iREx) at the Université de Montréal, published a detailed study of a planetary system known as Kepler-138 in the journal Nature Astronomy today.

Piaulet, who is part of Björn Benneke's research team, observed exoplanets Kepler-138c and Kepler-138d with NASA's Hubble and the retired Spitzer space telescopes and discovered that the planets -- which are about one and a half times the size of the Earth -- could be composed largely of water. These planets and a planetary companion closer to the star, Kepler-138b, had been discovered previously by NASA's Kepler Space Telescope.

Water wasn't directly detected, but by comparing the sizes and masses of the planets to models, they conclude that a significant fraction of their volume -- up to half of it -- should be made of materials that are lighter than rock but heavier than hydrogen or helium (which constitute the bulk of gas giant planets like Jupiter). The most common of these candidate materials is water.

"We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth, and that's why we called them super-Earths," explained Benneke. "However, we have now shown that these two planets, Kepler-138c and d, are quite different in nature: a big fraction of their entire volume is likely composed of water. It is the first time we observe planets that can be confidently identified as water worlds, a type of planet that was theorized by astronomers to exist for a long time."

"We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth, and that's why we called them super-Earths," explained Benneke. "However, we have now shown that these two planets, Kepler-138c and d, are quite different in nature: a big fraction of their entire volume is likely composed of water. It is the first time we observe planets that can be confidently identified as water worlds, a type of planet that was theorized by astronomers to exist for a long time."

With volumes more than three times that of Earth and masses twice as big, planets c and d have much lower densities than Earth. This is surprising because most of the planets just slightly bigger than Earth that have been studied in detail so far all seemed to be rocky worlds like ours. The closest comparison to the two planets, say researchers, would be some of the icy moons in the outer solar system that are also largely composed of water surrounding a rocky core.

"Imagine larger versions of Europa or Enceladus, the water-rich moons orbiting Jupiter and Saturn, but brought much closer to their star," explained Piaulet. "Instead of an icy surface, Kepler-138 c and d would harbor large water-vapor envelopes."

Researchers caution the planets may not have oceans like those on Earth directly at the planet's surface. "The temperature in Kepler-138c's and Kepler-138d's atmospheres is likely above the boiling point of water, and we expect a thick, dense atmosphere made of steam on these planets. Only under that steam atmosphere there could potentially be liquid water at high pressure, or even water in another phase that occurs at high pressures, called a supercritical fluid," Piaulet said.

Recently, another team at the University of Montreal found another planet, called TOI-1452 b, that could potentially be covered with a liquid-water ocean, but NASA's James Webb Space Telescope will be needed to study its atmosphere and confirm the presence of the ocean.

A new exoplanet in the system

In 2014, data from NASA's Kepler Space Telescope allowed astronomers to announce the detection of three planets orbiting Kepler-138, a red dwarf star in the constellation Lyra. This was based on a measurable dip in starlight as the planet momentarily passed in from of their star, a transit.

Benneke and his colleague Diana Dragomir, from the University of New Mexico, came up with the idea of re-observing the planetary system with the Hubble and Spitzer space telescopes between 2014 and 2016 to catch more transits of Kepler-138d, the third planet in the system, in order to study its atmosphere.

While earlier NASA Kepler space telescope observations only showed transits of three small planets around Kepler-138, Piaulet and her team were surprised to find that the Hubble and Spitzer observations suggested the presence of a fourth planet in the system, Kepler-138e.

This newly found planet is small and farther from its star than the three others, taking 38 days to complete an orbit. The planet is in the habitable zone of its star, a temperate region where a planet receives just the right amount of heat from its cool star to be neither too hot nor too cold to allow the presence of liquid water.

The nature of this additional, newly found planet, however, remains an open question because it does not seem to transit its host star. Observing the exoplanet's transit would have allowed astronomers to determine its size.

With Kepler-138e now in the picture, the masses of the previously known planets were measured again via the transit timing-variation method, which consists of tracking small variations in the precise moments of the planets' transits in front of their star caused by the gravitational pull of other nearby planets.

The researchers had another surprise: they found that the two water worlds Kepler-138c and d are "twin" planets, with virtually the same size and mass, while they were previously thought to be drastically different. The closer-in planet, Kepler-138b, on the other hand, is confirmed to be a small Mars-mass planet, one of the smallest exoplanets known to date.

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Machine learning reveals how black holes grow

As different as they may seem, black holes and Las Vegas have one thing in common: What happens there stays there -- much to the frustration of astrophysicists trying to understand how, when and why black holes form and grow. Black holes are surrounded by a mysterious, invisible layer -- the event horizon -- from which nothing can escape, be it matter, light or information. The event horizon swallows every bit of evidence about the black hole's past.

"Because of these physical facts, it had been thought impossible to measure how black holes formed," said Peter Behroozi, an associate professor at the University of Arizona Steward Observatory and a project researcher at the National Astronomical Observatory of Japan.

Together with Haowen Zhang, a doctoral student at Steward, Behroozi led an international team to use machine learning and supercomputers to reconstruct the growth histories of black holes, effectively peeling back their event horizons to reveal what lies beyond.

Simulations of millions of computer-generated "universes" revealed that supermassive black holes grow in lockstep with their host galaxies. This had been suspected for 20 years, but scientists had not been able to confirm this relationship until now. A paper with the team's findings has been published in Monthly Notices of the Royal Astronomical Society.

"If you go back to earlier and earlier times in the universe, you find that exactly the same relationship was present," said Behroozi, a co-author on the paper. "So, as the galaxy grows from small to large, its black hole, too, is growing from small to large, in exactly the same way as we see in galaxies today all across the universe."

Most, if not all, galaxies scattered throughout the cosmos are thought to harbor a supermassive black hole at their center. These black holes pack masses greater than 100,000 times that of the sun, with some boasting millions, even billions of solar masses. One of astrophysics' most vexing questions has been how these behemoths grow as fast they do, and how they form in the first place.

To find answers, Zhang, Behroozi and their colleagues created Trinity, a platform that uses a novel form of machine learning capable of generating millions of different universes on a supercomputer, each of which obeys different physical theories for how galaxies should form. The researchers built a framework in which computers propose new rules for how supermassive black holes grow over time. They then used those rules to simulate the growth of billions of black holes in a virtual universe and "observed" the virtual universe to test whether it agreed with decades of actual observations of black holes across the real universe. After millions of proposed and rejected rule sets, the computers settled on rules that best described existing observations.

"We're trying to understand the rules of how galaxies form," Behroozi said. "In a nutshell, we make Trinity guess what the physical laws may be and let them go in a simulated universe and see how that universe turns out. Does it look anything like the real one or not?"

According to the researchers, this approach works equally well for anything else inside of the universe, not just galaxies.

The project's name, Trinity, is in reference to its three main areas of study: galaxies, their supermassive black holes and their dark matter halos -- vast cocoons of dark matter that are invisible to direct measurements but whose existence is necessary to explain the physical characteristics of galaxies everywhere. In previous studies, the researchers used an earlier version of their framework, called the UniverseMachine, to simulate millions of galaxies and their dark matter halos. The team discovered that galaxies growing in their dark matter halos follow a very specific relationship between the mass of the halo and the mass of the galaxy.

"In our new work, we added black holes to this relationship," Behroozi said, "and then asked how black holes could grow in those galaxies to reproduce all the observations people have made about them."

"We have very good observations of black hole masses," said Zhang, the paper's lead author. "However, those are largely restricted to the local universe. As you look farther away, it becomes increasingly difficult, and eventually impossible, to accurately measure the relationships between the masses of black holes and their host galaxies. Because of that uncertainty, observations can't directly tell us whether that relationship holds up throughout the universe."

Trinity allows astrophysicists to sidestep not only that limitation, but also the event horizon information barrier for individual black holes by stitching together information from millions of observed black holes at different stages of their growth. Even though no individual black hole's history could be reconstructed, the researchers could measure the average growth history of all black holes taken together.

"If you put black holes into the simulated galaxies and enter rules about how they grow, you can compare the resulting universe to all the observations of actual black holes that we have," Zhang said. "We can then reconstruct how any black hole and galaxy in the universe looked from today back to the very beginning of the cosmos."

The simulations shed light on another puzzling phenomenon: Supermassive black holes -- like the one found in the center of the Milky Way -- grew most vigorously during their infancy, when the universe was only a few billion years old, only to slow down dramatically during the ensuing time, over the last 10 billion years or so.

"We've known for a while that galaxies have this strange behavior, where they reach a peak in their rate of forming new stars, then it dwindles over time, and then, later on, they stop forming stars altogether," Behroozi said. "Now, we've been able to show that black holes do the same: growing and shutting off at the same times as their host galaxies. This confirms a decades-old hypothesis about black hole growth in galaxies."

However, the result poses more questions, he added. Black holes are much smaller than the galaxies in which they live. If the Milky Way were scaled down to the size of Earth, its supermassive black hole would be the size of the period at the end of this sentence.

For the black hole to double in mass within the same timeframe as the larger galaxy requires synchronization between gas flows at vastly different scales. How black holes conspire with galaxies to achieve this balance is yet to be understood.

Read more at Science Daily

Drought encouraged Attila's Huns to attack the Roman empire, tree rings suggest

Hunnic peoples migrated westward across Eurasia, switched between farming and herding, and became violent raiders in response to severe drought in the Danube frontier provinces of the Roman empire, a new study argues.

Hungary has just experienced its driest summer since meteorological measurements began, devastating the country's usually productive farmland. Archaeologists now suggest that similar conditions in the 5th century may have encouraged animal herders to become raiders, with devastating consequences for the Roman empire.

The study, published today in the Journal of Roman Archaeology, argues that extreme drought spells from the 430s -- 450s CE disrupted ways of life in the Danube frontier provinces of the eastern Roman empire, forcing Hunnic peoples to adopt new strategies to 'buffer against severe economic challenges'.

The authors, Associate Professor Susanne Hakenbeck from Cambridge's Department of Archaeology and Professor Ulf Büntgen from the University's Department of Geography, came to their conclusions after assessing a new tree ring-based hydroclimate reconstruction, as well as archaeological and historical evidence.

The Hunnic incursions into eastern and central Europe in the 4th and 5th centuries CE have long been viewed as the initial crisis that triggered the so-called 'Great Migrations' of 'Barbarian Tribes', leading to the fall of the Roman empire. But where the Huns came from and what their impact on the late Roman provinces actually was unclear.

New climate data reconstructed from tree rings by Prof Büntgen and colleagues provides information about yearly changes in climate over the last 2000 years. It shows that Hungary experienced episodes of unusually dry summers in the 4th and 5th centuries. Hakenbeck and Büntgen point out that climatic fluctuations, in particular drought spells from 420 to 450 CE, would have reduced crop yields and pasture for animals beyond the floodplains of the Danube and Tisza.

Büntgen said: "Tree ring data gives us an amazing opportunity to link climatic conditions to human activity on a year-by-year basis. We found that periods of drought recorded in biochemical signals in tree-rings coincided with an intensification of raiding activity in the region."

Recent isotopic analysis of skeletons from the region, including by Dr Hakenbeck, suggests that Hunnic peoples responded to climate stress by migrating and by mixing agricultural and pastoral diets.

Hakenbeck said: "If resource scarcity became too extreme, settled populations may have been forced to move, diversify their subsistence practices and switch between farming and mobile animal herding. These could have been important insurance strategies during a climatic downturn."

But the study also argues that some Hunnic peoples dramatically changed their social and political organization to become violent raiders.

From herders to raiders

Hunnic attacks on the Roman frontier intensified after Attila came to power in the late 430s. The Huns increasingly demanded gold payments and eventually a strip of Roman territory along the Danube. In 451 CE, the Huns invaded Gaul and a year later they invaded northern Italy.

Traditionally, the Huns have been cast as violent barbarians driven by an "infinite thirst for gold." But, as this study points out, the historical sources documenting these events were primary written by elite Romans who had little direct experience of the peoples and events they described.

"Historical sources tell us that Roman and Hun diplomacy was extremely complex," Dr Hakenbeck said. "Initially it involved mutually beneficial arrangements, resulting in Hun elites gaining access to vast amounts of gold. This system of collaboration broke down in the 440s, leading to regular raids of Roman lands and increasing demands for gold."

The study argues that if current dating of events is correct, the most devastating Hunnic incursions of 447, 451 and 452 CE coincided with extremely dry summers in the Carpathian Basin.

Hakenbeck said: "Climate-induced economic disruption may have required Attila and others of high rank to extract gold from the Roman provinces to keep war bands and maintain inter-elite loyalties. Former horse-riding animal herders appear to have become raiders."

Historical sources describe the Huns at this time as a highly stratified group with a military organization that was difficult to counter, even for the Roman armies.

The study suggests that one reason why the Huns attacked the provinces of Thrace and Illyricum in 422, 442, and 447 CE was to acquire food and livestock, rather than gold, but accepts that concrete evidence is needed to confirm this. The authors also suggest that Attila demanded a strip of land 'five days' journey wide' along the Danube because this could have offered better grazing in a time of drought.

Hakenbeck said: "Climate alters what environments can provide and this can lead people to make decisions that affect their economy, and their social and political organization. Such decisions are not straightforwardly rational, nor are their consequences necessarily successful in the long term."

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Early humans may have first walked upright in the trees

Human bipedalism -- walking upright on two legs -- may have evolved in trees, and not on the ground as previously thought, according to a new study involving UCL researchers.

In the study, published today in the journal Science Advances, researchers from UCL, the University of Kent, and Duke University, USA, explored the behaviours of wild chimpanzees -- our closest living relative -- living in the Issa Valley of western Tanzania, within the region of the East African Rift Valley. Known as 'savanna-mosaic' -- a mix of dry open land with few trees and patches of dense forest -- the chimpanzees' habitat is very similar to that of our earliest human ancestors and was chosen to enable the scientists to explore whether the openness of this type of landscape could have encouraged bipedalism in hominins.

The study is the first of its kind to explore if savanna-mosaic habitats would account for increased time spent on the ground by the Issa chimpanzees, and compares their behaviour to other studies on their solely forest-dwelling cousins in other parts of Africa.

Overall, the study found that the Issa chimpanzees spent as much time in the trees as other chimpanzees living in dense forests, despite their more open habitat, and were not more terrestrial (land-based) as expected.

Furthermore, although the researchers expected the Issa chimpanzees to walk upright more in open savanna vegetation, where they cannot easily travel via the tree canopy, more than 85% of occurrences of bipedalism took place in the trees.

The authors say that their findings contradict widely accepted theories that suggest that it was an open, dry savanna environment that encouraged our prehistoric human relatives to walk upright -- and instead suggests that they may have evolved to walk on two feet to move around the trees.

Study co-author Dr Alex Piel (UCL Anthropology) said: "We naturally assumed that because Issa has fewer trees than typical tropical forests, where most chimpanzees live, we would see individuals more often on the ground than in the trees. Moreover, because so many of the traditional drivers of bipedalism (such as carrying objects or seeing over tall grass, for example) are associated with being on the ground, we thought we'd naturally see more bipedalism here as well. However, this is not what we found.

"Our study suggests that the retreat of forests in the late Miocene-Pliocene era around five million years ago and the more open savanna habitats were in fact not a catalyst for the evolution of bipedalism. Instead, trees probably remained essential to its evolution -- with the search for food-producing trees a likely a driver of this trait."

To establish their findings, the researchers recorded more than 13,700 instantaneous observations of positional behaviour from 13 chimpanzee adults (six females and seven males), including almost 2,850 observations of individual locomotor events (e.g., climbing, walking, hanging, etc.), over the course of the 15-month study. They then used the relationship between tree/land-based behaviour and vegetation (forest vs woodland) to investigate patterns of association. Similarly, they noted each instance of bipedalism and whether it was associated with being on the ground or in the trees.

The authors note that walking on two feet is a defining feature of humans when compared to other great apes, who "knuckle walk." Yet, despite their study, researchers say why humans alone amongst the apes first began to walk on two feet still remains a mystery.

Study co-author Dr Fiona Stewart (UCL Anthropology) said: "To date, the numerous hypotheses for the evolution of bipedalism share the idea that hominins (human ancestors) came down from the trees and walked upright on the ground, especially in more arid, open habitats that lacked tree cover. Our data do not support that at all.

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Antihelium nuclei as messengers from the depths of the galaxy

How are galaxies born, and what holds them together? Astronomers assume that dark matter plays an essential role. However, as yet it has not been possible to prove directly that dark matter exists. A research team including Technical University of Munich (TUM) scientists has now measured for the first time the survival rate of antihelium nuclei from the depths of the galaxy -- a necessary prerequisite for the indirect search for Dark Matter.

Many things point to the existence of dark matter. The way in which galaxies move in galactic clusters, or how fast stars circle the center of a galaxy results in calculations which indicate that there must be far more mass present than what we can see. Approximately 85 percent of our Milky Way for example consists of a substance which is not visible and which can only be detected based on its gravitational effects. As of today it has still not been possible to directly prove the existence of this material.

Several theoretical models of dark matter predict that it could be composed of particles which interact weakly with one another. This produces antihelium-3 nuclei, which consist of two antiprotons and one antineutron. These nuclei are also generated in high-energy collisions between cosmic radiation and common matter like hydrogen and helium -- however, with energies different from those that would be expected in the interaction of dark matter particles.

In both processes, the antiparticles originate in the depths of the galaxy, several tens of thousands of lightyears away from us. After their creation, a part of them makes its way in our direction. How many of these particles survive this journey unscathed and reach the vicinity of the Earth as messengers of their formation process determines the transparency of the Milky Way for antihelium nuclei. Until now scientists have only been able to roughly estimate this value. However, an improved approximation of transparency, a unit of measure for the number and energies of antinuclei, will be important for interpreting future antihelium measurements.

LHC particle accelerator as antimatter factory

Researchers from the ALICE collaboration have now carried out measurements that have enabled them to determine the transparency more precisely for the first time. ALICE stands for A Large Ion Collider Experiment and is one of the largest experiments in the world to explore physics on the smallest length scales. ALICE is part of the Large Hadron Collider (LHC) at CERN.

The LHC can generate large amounts of light antinuclei such as antihelium. To do so, protons and lead atoms are each put on a collision course. The collisions produce particle showers which are then recorded by the detector of the ALICE experiment. Thanks to several subsystems of the detector, the researchers can then detect the antihelium-3 nuclei that have formed and follow their trails in the detector material. This makes it possible to quantify the probability that an antihelium-3 nucleus will interact with the detector material and disappear. Scientists from TUM and the Excellence Cluster ORIGINS have contributed significantly to the analysis of the experimental data.

Galaxy transparent for antinuclei

Using simulations, the researchers were able to transfer the findings from the ALICE experiment to the entire galaxy. The result: About half of the antihelium-3 nuclei which were expected to be generated in the interaction of dark matter particles would reach the vicinity of the Earth. Our Milky Way is thus 50 percent permeable for these antinuclei. For antinuclei generated in collisions between cosmic radiation and the interstellar medium, the resulting transparency varies from 25 to 90 percent with increasing antihelium-3 momentum. However, these antinuclei can be distinguished from those generated from dark matter based on their higher energy.

This means that antihelium nuclei can not only travel long distances in the Milky Way, but also serve as important informants in future experiments: Depending on how many antinuclei arrive at the Earth and with which energies, the origin of these well-travelled messengers can be interpreted as cosmic rays or dark matter thanks to the new calculations.

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Shedding light on photosynthesis at sea

Plants that live on land, such as spinach, grow by using sunlight to perform photosynthesis. How, then, do algae photosynthesize in the deep sea, an environment where only a little light reaches them?

Land plants mainly absorb red and blue light from the sun and use it for photosynthesis. However, only weak blue-green light reaches the ocean floor. Therefore, macroalgae growing in the ocean have developed a protein, a so-called photosynthetic antenna, that efficiently utilizes this blue-green light. The photosynthetic antenna of marine macroalgae is very similar to that of land plants but differs in the structure of the pigments bound to it. Land plants have two types of pigments bound to their photosynthetic antennae, namely carotenoids and chlorophylls. In the marine green macroalga Codium fragile, the major carotenoids are substituted with siphonaxanthin while some chlorophyll a molecules are replaced by chlorophyll b molecules. Siphonaxanthin and chlorophyll b are known to contribute to increased absorption of green light and blue-green light, respectively, but the mechanism has not yet been fully understood.

Responding to this gap, a research team led by Associate Professor Ritsuko Fujii, from the Research Center for Artificial Photosynthesis (ReCAP) at Osaka Metropolitan University, and graduate student Soichiro Seki, from the Graduate School of Science at Osaka City University, used cryogenic electron microscopy to investigate the structures and binding environments of pigments bound to the photosynthetic antenna of C. fragile. The results allow for the elucidation of the molecular mechanism by which blue-green light -- the only light available in deep seawater -- is efficiently utilized for photosynthesis. Their findings were published in BBA Advances on November 11, 2022.

High-resolution analysis by cryogenic electron microscopy showed that siphonaxanthin in C. fragile is greatly distorted and forms hydrogen bonds with the surrounding protein at two locations. This structural feature is deemed a key factor in siphonaxanthin's ability to absorb green light. Additionally, the researchers successfully detected the difference between chlorophyll a and chlorophyll b, and they clarified several chlorophyll molecule substitution sites. When the substitution occurs, the adjacent region of chlorophyll b clusters becomes wider, enabling better absorption of blue-green light. In other words, the team was able to obtain information on the pigment coordinates, contributing to a better understanding of the mechanism of more efficient photosynthesis.

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Flying snakes help scientists design new robots

Robots have been designed to move in ways that mimic animal movements, such as walking and swimming. Scientists are now considering how to design robots that mimic the gliding motion exhibited by flying snakes.

In Physics of Fluids, by AIP Publishing, researchers from the University of Virginia and Virginia Tech explored the lift production mechanism of flying snakes, which undulate side-to-side as they move from the tops of trees to the ground to escape predators or to move around quickly and efficiently. The undulation allows snakes to glide for long distances, as much as 25 meters from a 15-meter tower.

To understand how the undulations provide lift, the investigators developed a computational model derived from data obtained through high-speed video of flying snakes. A key component of this model is the cross-sectional shape of the snake's body, which resembles an elongated frisbee or flying disc.

The cross-sectional shape is essential for understanding how the snake can glide so far. In a frisbee, the spinning disc creates increased air pressure below the disc and suction on its top, lifting the disc into the air. To help create the same type of pressure differential across its body, the snake undulates side to side, producing a low-pressure region above its back and a high-pressure region beneath its belly. This lifts the snake and allows it to glide through the air.

"The snake's horizontal undulation creates a series of major vortex structures, including leading edge vortices, LEV, and trailing edge vortices, TEV," said author Haibo Dong of the University of Virginia. "The formation and development of the LEV on the dorsal, or back, surface of the snake body plays an important role in producing lift."

The LEVs form near the head and move back along the body. The investigators found that the LEVs hold for longer intervals at the curves in the snake's body before being shed. These curves form during the undulation and are key to understanding the lift mechanism.

The group considered several features, such as the angle of attack that the snake forms with the oncoming airflow and the frequency of its undulations, to determine which were important in producing glide. In their natural setting, flying snakes typically undulate at a frequency between 1-2 times per second. Surprisingly, the researchers found that more rapid undulation decreases aerodynamic performance.

"The general trend we see is that a frequency increase leads to an instability in the vortex structure, causing some vortex tubes to spin. The spinning vortex tubes tend to detach from the surface, leading to a decrease in lift," said Dong.

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Humans and nature: The distance is growing

The idea that humans are facing a global extinction of experience of nature is popular, but there is poor empirical evidence of its reality. To shed more light on this, the scientists measured how the average distance from an individual's home to the nearest area with low human impact changed in the last decade. They found that humans currently live 9.7 km away from a natural area on average, which is 7% further away than in the year 2000. Europe and East Asia have the highest average distance to natural areas, such as 22 km in Germany and 16 km in France. "What is striking is that all other countries in the world are following a similar pattern," explains first author Dr Victor Cazalis, a postdoctoral researcher at iDiv and Leipzig University.

The authors also showed that tree cover within cities has declined worldwide since 2000, particularly in Central Africa and South-East Asia. "This finding suggests that the possibility for the urban population to access green spaces is reducing as well," concludes Dr Gladys Barragan-Jason, a researcher at the Theoretical and Experimental Ecology Station and co-author of the study. "Indeed, the study reveals that the destruction of natural areas combined with a strong increase in urban population is leading to a growing spatial distance between humans and nature, especially in Asia, Africa and South America."

In the same study, the authors systematically searched for scientific publications assessing a trend in experiences of nature: from direct ones such as hiking in national parks, to vicarious experiences like natural settings in cultural products like cartoons, computer games or books. They found that the number of studies assessing these trends was very low (N=18), with a strong bias towards the US, Europe and Japan. This shows that any claim about the extinction of nature experience is based on poor evidence and that more studies should investigate this question, especially in Africa, Latin America and Asia.

The 18 studies found by the authors show for instance a decline in visits to nature parks in the US and Japan, a decrease in camping activities in the US, and a decrease in the number of flower species observed by Japanese children. They also find signs of disconnection in the depletion of natural elements in novels, songs, children's albums and animated movies, which are less and less imbued with natural imagery (as shown e.g. by an iDiv study from 2021).

Despite these examples of decline, other interactions are stagnating or even increasing. Watching wildlife documentaries or interacting with wild animals in video games is, for example, more common than a few years ago. "New ways of digitally interacting with nature have certainly emerged or increased in recent decades," says Gladys Barragan-Jason. "But several former studies show that these interactions have a lesser effect on our sense of connection with nature than direct interaction."

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VLA and ALMA study Jupiter and Io

While the National Science Foundation's Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) frequently reveal important new facts about objects far beyond our own Milky Way Galaxy -- at distances of many millions or billions of light-years -- they also are vital tools for unraveling much closer mysteries, right here in our own Solar System. A pair of recent scientific papers illustrate how these telescopes are helping planetary scientists understand the workings of the Solar System's largest planet, Jupiter, and its innermost moon Io.

Jupiter's atmosphere is complex and dynamic, and changes rapidly. To study the giant planet's atmosphere at different depths, scientists combined observations made with instruments aboard NASA's Juno spacecraft, in orbit around Jupiter, with observations with the VLA. They collected data about the distribution of the trace gas ammonia at different levels in the atmosphere to help determine the vertical structure of the atmosphere. These observations needed to be sufficiently detailed to combine Juno's long wavelength observations with the VLA's high-frequency resolution to understand vertical transport in the atmosphere. The spatial resolution of the ground-based VLA observations was comparable to that of the instrument aboard the spacecraft orbiting the planet. These observations produced the highest-resolution radio image yet made of Jupiter. This technique is helping the scientists advance their understanding of Jupiter's deep atmosphere.

Io, whose interior constantly is heated by strong gravitational tidal forces, is the most volcanically-active body in our Solar System. The moon has a tenuous atmosphere primarily composed of Sulphur Dioxide (SO2), which comes from eruptions of its many volcanoes and sublimation of its SO2 surface frost. Scientists have used ALMA to study the trace gases of Sodium Chloride (NaCl -- table salt) and Potassium Chloride (KCl) in the atmosphere. They found that these compounds are largely confined in extent and are at high temperatures, indicating that they, too, are expelled by volcanoes. They also found that they are in different locations from where the SO2 is emitted, which suggests that there may be differences in the subsurface magma or in the eruptive processes between the volcanoes that emit SO2 and those that emit NaCl and KCl.

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Changes in Earth's orbit may have triggered ancient warming event

Changes in Earth's orbit that favored hotter conditions may have helped trigger a rapid global warming event 56 million years ago that is considered an analogue for modern climate change, according to an international team of scientists.

"The Paleocene-Eocene Thermal Maximum is the closest thing we have in the geologic record to anything like what we're experiencing now and may experience in the future with climate change," said Lee Kump, professor of geosciences at Penn State. "There has been a lot of interest in better resolving that history, and our work addresses important questions about what triggered the event and the rate of carbon emissions."

The scientists analyzed core samples from a well-preserved record of the PETM near the Maryland coast using astrochronology, a technique for dating sediments against orbital patterns that occur over tens to hundreds of thousands of years, known as Milankovitch cycles.

They found the shape of Earth's orbit, or eccentricity, and the wobble in its rotation, or precession, favored hotter conditions at the onset of the PETM and that these orbital configurations together may have played a role in triggering the event.

"An orbital trigger may have led to the carbon release that caused several degrees of global warming during the PETM as opposed to what's a more popular interpretation at the moment that massive volcanism released the carbon and triggered the event," said Kump, the John Leone Dean in the College of Earth and Mineral Sciences.

The findings, published in the journal Nature Communications, also indicated the onset of the PETM lasted about 6,000 years. Previous estimates have ranged from several years to tens of thousands of years. The timing is important to understand the rate at which carbon was released into the atmosphere, the scientists said.

"This study allows us to refine our carbon cycle models to better understand how the planet reacts to an injection of carbon over these timescales and to narrow down the possibilities for the source of the carbon that drove the PETM," said Mingsong Li, assistant professor in the School of Earth and Space Sciences at Peking University and a former assistant research professor of geosciences at Penn State who is lead author on the study.

A 6,000-year onset, coupled with estimates that 10,000 gigatons of carbon were injected into the atmosphere as the greenhouse gases carbon dioxide or methane, indicates that about one and a half gigatons of carbon were released per year.

"Those rates are close to an order of magnitude slower than the rate of carbon emissions today, so that is cause for some concern," Kump said. "We are now emitting carbon at a rate that's 5 to 10 times higher than our estimates of emissions during this geological event that left an indelible imprint on the planet 56 million years ago."

The scientists conducted a time series analysis of calcium content and magnetic susceptibility found in the cores, which are proxies for changes in orbital cycles, and used that information to estimate the pacing of the PETM.

Earth's orbit varies in predictable, calculable ways due to gravitational interactions with the sun and other planets in the solar system. These changes impact how much sunlight reaches Earth and its geographic distribution and therefore influence the climate.

"The reason there's an expression in the geologic record of these orbital changes is because they affect climate," Kump said. "And that affects how productive marine and terrestrial organisms are, how much rainfall there is, how much erosion there is on the continents and therefore how much sediment is carried into the ocean environment."

Erosion from the paleo Potomac and Susquehanna rivers, which at the onset of the PETM may have rivaled the discharge of the Amazon River, carried sediments to the ocean where they were deposited on the continental shelf. This formation, called the Marlboro Clay, is now inland and offers one of the best-preserved examples of the PETM.

"We can develop histories by coring down through the layers of sediment and extracting specific cycles that are creating this story, just like you could extract each note from a song," Kump said. "Of course, some of records are distorted and there are gaps -- but we can use the same types of statistical methods that are used in apps that can determine what song you are trying to sing. You can sing a song and if you forget half the words and skip a chorus, it will still be able to determine the song, and we can use that same approach to reconstruct these records."

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Fossil site reveals giant arthropods dominated the seas 470 million years ago

Discoveries at a major new fossil site in Morocco suggest giant arthropods -- relatives of modern creatures including shrimps, insects and spiders -- dominated the seas 470 million years ago.

Early evidence from the site at Taichoute, once undersea but now a desert, records numerous large "free-swimming" arthropods.

More research is needed to analyse these fragments, but based on previously described specimens, the giant arthropods could be up to 2m long.

An international research team say the site and its fossil record are very different from other previously described and studied Fezouata Shale sites from 80km away.

They say Taichoute (considered part of the wider "Fezouata Biota") opens new avenues for paleontological and ecological research.

"Everything is new about this locality -- its sedimentology, paleontology, and even the preservation of fossils -- further highlighting the importance of the Fezouata Biota in completing our understanding of past life on Earth," said lead author Dr Farid Saleh, from the University of Lausanne and and Yunnan University.

Dr Xiaoya Ma, from the University of Exeter and Yunnan University, added: "While the giant arthropods we discovered have not yet been fully identified, some may belong to previously described species of the Fezouata Biota, and some will certainly be new species.

"Nevertheless, their large size and free-swimming lifestyle suggest they played a unique role in these ecosystems."

The Fezouata Shale was recently selected as one of the 100 most important geological sites worldwide because of its importance for understanding the evolution during the Early Ordovician period, about 470 million years ago.

Fossils discovered in these rocks include mineralised elements (eg shells), but some also show exceptional preservation of soft parts such as internal organs, allowing scientists to investigate the anatomy of early animal life on Earth.

Animals of the Fezouata Shale, in Morocco's Zagora region, lived in a shallow sea that experienced repeated storm and wave activities, which buried the animal communities and preserved them in place as exceptional fossils.

However, nektonic (or free-swimming) animals remain a relatively minor component overall in the Fezouata Biota.

The new study reports the discovery of the Taichoute fossils, preserved in sediments that are a few million years younger than those from the Zagora area and are dominated by fragments of giant arthropods.

"Carcasses were transported to a relatively deep marine environment by underwater landslides, which contrasts with previous discoveries of carcass preservation in shallower settings, which were buried in place by storm deposits," said Dr Romain Vaucher, from the University of Lausanne.

Professor Allison Daley, also from the University of Lausanne, added: "Animals such as brachiopods are found attached to some arthropod fragments, indicating that these large carapaces acted as nutrient stores for the seafloor dwelling community once they were dead and lying on the seafloor."

Dr Lukáš Laibl, from the Czech Academy of Sciences, who had the opportunity to participate in the initial fieldwork, said: "Taichoute is not only important due to the dominance of large nektonic arthropods.

"Even when it comes to trilobites, new species so far unknown from the Fezouata Biota are found in Taichoute."

Dr Bertrand Lefebvre, from the University of Lyon, who is the senior author on the paper, and who has been working on the Fezouata Biota for the past two decades, concluded: "The Fezouata Biota keeps surprising us with new unexpected discoveries."

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Intermittent fasting may reverse type 2 diabetes

After an intermittent fasting diet intervention, patients achieved complete diabetes remission, defined as an HbA1c (average blood sugar) level of less than 6.5% at least one year after stopping diabetes medication, according to a new study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.

Intermittent fasting diets have become popular in recent years as an effective weight loss method. With intermittent fasting, you only eat during a specific window of time. Fasting for a certain number of hours each day or eating just one meal a couple of days a week can help your body burn fat. Research shows intermittent fasting can lower your risk of diabetes and heart disease.

"Type 2 diabetes is not necessarily a permanent, lifelong disease. Diabetes remission is possible if patients lose weight by changing their diet and exercise habits," said Dongbo Liu, Ph.D., of Hunan Agricultural University in Changsha, China. "Our research shows an intermittent fasting, Chinese Medical Nutrition Therapy (CMNT), can lead to diabetes remission in people with type 2 diabetes, and these findings could have a major impact on the over 537 million adults worldwide who suffer from the disease."

The researchers conducted a 3-month intermittent fasting diet intervention among 36 people with diabetes and found almost 90% of participants, including those who took blood sugar-lowering agents and insulin, reduced their diabetes medication intake after intermittent fasting. Fifty-five percent of these people experienced diabetes remission, discontinued their diabetes medication and maintained it for at least one year.

The study challenges the conventional view that diabetes remission can only be achieved in those with a shorter diabetes duration (0-6 years). Sixty-five percent of the study participants who achieved diabetes remission had a diabetes duration of more than 6 years (6-11 years).

"Diabetes medications are costly and a barrier for many patients who are trying to effectively manage their diabetes. Our study saw medication costs decrease by 77% in people with diabetes after intermittent fasting," Liu said.

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Sound recording made of dust devils (tiny tornadoes of dust, grit) on Mars

When the rover Perseverance landed on Mars, it was equipped with the first working microphone on the planet's surface. Scientists have used it to make the first-ever audio recording of an extraterrestrial whirlwind.

The study was published in Nature Communications by planetary scientist Naomi Murdoch and a team of researchers at the National Higher French Institute of Aeronautics and Space and NASA. Roger Wiens, professor of earth, atmospheric and planetary sciences in Purdue University's College of Science, leads the instrument team that made the discovery. He is the principal investigator of Perseverance's SuperCam, a suite of tools that comprise the rover's "head" that includes advanced remote-sensing instruments with a wide range of spectrometers, cameras and the microphone.

"We can learn a lot more using sound than we can with some of the other tools," Wiens said. "They take readings at regular intervals. The microphone lets us sample, not quite at the speed of sound, but nearly 100,000 times a second. It helps us get a stronger sense of what Mars is like."

The microphone is not on continuously; it records for about three minutes every couple of days. Getting the whirlwind recording, Wiens said, was lucky, though not necessarily unexpected. In the Jezero Crater, where Perseverance landed, the team has observed evidence of nearly 100 dust devils -- tiny tornadoes of dust and grit -- since the rover's landing. This is the first time the microphone was on when one passed over the rover.

The sound recording of the dust devil, taken together with air pressure readings and time-lapse photography, help scientists understand the Martian atmosphere and weather.

"We could watch the pressure drop, listen to the wind, then have a little bit of silence that is the eye of the tiny storm, and then hear the wind again and watch the pressure rise," Wiens said. It all happened in a few seconds. "The wind is fast -- about 25 miles per hour, but about what you would see in a dust devil on Earth. The difference is that the air pressure on Mars is so much lower that the winds, while just as fast, push with about 1% of the pressure the same speed of wind would have back on Earth. It's not a powerful wind, but clearly enough to loft particles of grit into the air to make a dust devil."

The information indicates that future astronauts will not have to worry about gale-force winds blowing down antennas or habitats -- so future Mark Watneys won't be left behind -- but the wind may have some benefits. The breezes blowing grit off the solar panels of other rovers -- especially Opportunity and Spirit -- may be what helped them last so much longer.

"Those rover teams would see a slow decline in power over a number of days to weeks, then a jump. That was when wind cleared off the solar panels," Wiens said.

The lack of such wind and dust devils in the Elysium Planitia where the InSIght mission landed may help explain why that mission is winding down.

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Discovering rare red spiral galaxy population from early universe with the James Webb Space Telescope

Spiral galaxies represent one of the most spectacular features in our universe. Among them, spiral galaxies in the distant universe contain significant information about their origin and evolution. However, we have had a limited understanding of these galaxies due to them being too distant to study in detail. "While these galaxies were already detected among the previous observations using NASA's Hubble Space Telescope and Spitzer Space Telescope, their limited spatial resolution and/or sensitivity did not allow us to study their detailed shapes and properties," explains Junior Researcher Yoshinobu Fudamoto from Waseda University in Japan, who has been researching galaxies' evolution.

Now, NASA's James Webb Space Telescope (JWST) has taken things to the next level. In its very first imaging of the galaxy cluster, SMACS J0723.3-7327, JWST has managed to capture infrared images of a population of red spiral galaxies at an unprecedented resolution, revealing their morphology in detail!

Against this backdrop, in a recent article published in The Astrophysical Journal Letters on 21 October 2022, a team of researchers comprising Junior Researcher Yoshinobu Fudamoto, Prof. Akio K. Inoue, and Dr. Yuma Sugahara from Waseda University, Japan, has revealed surprising insights into these red spiral galaxies. Among the several red spiral galaxies detected, the researchers focused on the two most extremely red galaxies, RS13 and RS14. Using spectral energy distribution (SED) analysis, the researchers measured the distribution of energy over wide wavelength range for these galaxies. The SED analysis revealed that these red spiral galaxies belong to the early universe from a period known as the "cosmic noon" (8-10 billion years ago), which followed the Big Bang and the "cosmic dawn." Remarkably, these are among the farthest known spiral galaxies till date.

Rare, red spiral galaxies account for only 2% of the galaxies in the local universe. This discovery of red spiral galaxies in the early universe, from the JWST observation covering only an insignificant fraction of space, suggests that such spiral galaxies existed in large numbers in the early universe.

The researchers further discovered that one of the red spiral galaxies, RS14, is a "passive" (not forming stars) spiral galaxy, contrary to the intuitive expectation that galaxies in the early universe would be actively forming stars. This detection of a passive spiral galaxy in the JWST's limited field of view is particularly surprising, since it suggests that such passive spiral galaxies could also exist in large numbers in the early universe.

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True giant wombat gives Diprotodon podium a wobble

If you thought Australia was home to only one ancient 'giant wombat', think again.

While the Diprotodon -- the extinct megafauna species that is distantly related to wombats but was the size of a small car -- is commonly (but incorrectly) thought of as Australia's 'giant wombat', researchers from Griffith University have shed light on a large species that does belong in the modern-day wombat family.

The complete skull of this true fossil giant wombat, found in a Rockhampton cave in Queensland and estimated to be around 80,000 years old, has been described for the first time by a team led by Associate Professor Julien Louys from Griffith's Australian Research Centre for Human Evolution.

Associate Professor Louys said the discovery provided unprecedented insights into the biology and appearance of these previously little known 'gentle giants'.

"The extinct megafauna of Australia never ceases to amaze and intrigue not just Australians, but people all over the world," he said.

"Although one of the most charismatic of the giant mammals to go extinct, Diprotodon is commonly referred to as a 'giant wombat'. But this is incorrect as Diprotodon belongs to an entirely different family -- equivalent to saying a hippo is just a giant pig.

"There were however, true giant wombats. These have traditionally been poorly known, but the discovery of the most complete skull of one of these giants, Ramsayia, has provided us with an opportunity to reconstruct what this creature looked like, where and when it lived, and how the evolution of giant wombats took place in Australia."

The cranium and mandible of the Ramsayia magna fossil was discovered from the rear of the front chamber of Lower Johansons Cave in Rockhampton in the early 2000s, but it was only through subsequent excavations and analysis by Associate Professor Louys's team that is was confirmed as belonging to a previously described but very poorly known species.

Extinct giant wombats of the family Vombatidae (broadly defined as twice the size of modern wombats) are rarer than the fossil diprotodontids that are often popularly -- and incorrectly -- referred to as giant wombats.

Associate Professor Louys said this giant wombat -- Ramsayia -- had extensive cranial sinuses, which had not been previously reported for a wombat.

"This indicates that the wombat had a large, rounded skull for the attachment of specific and strong chewing muscles," he said.

"The giant wombat also possessed a 'premaxillary spine', an indication that it had a large, fleshy nose.

"In this paper, we show that all true giant wombats evolved large body sizes first, then individually became quite specialised to eat different types of grasses.

"We also dated this species as being about 80,000 years old. This is the first date for this species and is much earlier than human arrival in Australia, although we still don't know exactly when or why this species became extinct."

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Extinct 'monkey lemur' shows similarities to fossil humans

Analysis of teeth of extinct lemurs has revealed fascinating clues to the evolution of humans, a University of Otago study has found.

Lead author Dr Ian Towle, of the Sir John Walsh Research Institute in the Faculty of Dentistry, says the "surprisingly large" monkey lemur, Archaeolemur, had novel anatomical features not seen in living lemurs, such as lacking a 'tooth comb' in the front of the mouth for grooming.

"These extinct lemurs are so different to those alive today. They also show fascinating similarities to monkeys and apes, including humans," he says.

The study, published in the American Journal of Biological Anthropology, aimed to assess the diet of Archaeolemur by analysing chipping in 447 teeth, comparing chipping frequencies to those of other primates.

The results were surprising -- with these remarkable extinct lemurs with dentitions resembling baboons in shape; but presenting tooth chipping patterns similar to fossil hominins such as Neanderthals.

"Archaeolemur tooth chipping patterns are unlike any living primate, with their front teeth showing substantial fractures, often with numerous tooth chips on a single tooth, yet very little chipping on their back teeth.

"Similar tooth fracture patterns are observed in fossil hominins, such as Neanderthals. Typically, in Neanderthals these fracture patterns are thought to be related to tool-use behaviours," Dr Towle says.

The results fit with previous research on Archaeolemur, in particular evidence that their large and robust front teeth may have been used to process a diet containing hard and tough foods.

Dr Towle thinks the study raises the "fascinating possibility" that stone tools do not necessarily explain the high rate of fractures on Neanderthal teeth.

"Archaeolemur shows similar tooth chipping patterns, yet there is no evidence to suggest they were capable of, or used, such tools.

"Studying extinct primates not only provides crucial insight into their diet and behaviour, but also elucidates our own evolutionary history."

Given the overlap in skull and dental shape, and potential similarities in diet and behaviour, it is perhaps not surprising that Archaeolemur  was thought to be an ape when first discovered in Madagascar over 100 years ago.

"Archaeolemur is a brilliant example of convergent evolution, showing remarkable similarities to monkeys and apes. This species also highlights the extent to which lemurs in Madagascar diversified into a variety of ecological niches."

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Without more data, a black hole's origins can be 'spun' in any direction

Clues to a black hole's origins can be found in the way it spins. This is especially true for binaries, in which two black holes circle close together before merging. The spin and tilt of the respective black holes just before they merge can reveal whether the invisible giants arose from a quiet galactic disk or a more dynamic cluster of stars.

Astronomers are hoping to tease out which of these origin stories is more likely by analyzing the 69 confirmed binaries detected to date. But a new study finds that for now, the current catalog of binaries is not enough to reveal anything fundamental about how black holes form.

In a study appearing in the journal Astronomy and Astrophysics Letters, MIT physicists show that when all the known binaries and their spins are worked into models of black hole formation, the conclusions can look very different, depending on the particular model used to interpret the data.

A black hole's origins can therefore be "spun" in different ways, depending on a model's assumptions of how the universe works.

"When you change the model and make it more flexible or make different assumptions, you get a different answer about how black holes formed in the universe," says study co-author Sylvia Biscoveanu, an MIT graduate student working in the LIGO Laboratory. "We show that people need to be careful because we are not yet at the stage with our data where we can believe what the model tells us."

The study's co-authors include Colm Talbot, an MIT postdoc; and Salvatore Vitale, an associate professor of physics and a member of the Kavli Institute of Astrophysics and Space Research at MIT.

A tale of two origins

Black holes in binary systems are thought to arise via one of two paths. The first is through "field binary evolution," in which two stars evolve together and eventually explode in supernovae, leaving behind two black holes that continue circling in a binary system. In this scenario, the black holes should have relatively aligned spins, as they would have had time -- first as stars, then black holes -- to pull and tug each other into similar orientations. If a binary's black holes have roughly the same spin, scientists believe they must have evolved in a relatively quiet environment, such as a galactic disk.

Black hole binaries can also form through "dynamical assembly," where two black holes evolve separately, each with its own distinct tilt and spin. By some extreme astrophysical processes, the black holes are eventually brought together, close enough to form a binary system. Such a dynamical pairing would likely occur not in a quiet galactic disk, but in a more dense environment, such as a globular cluster, where the interaction of thousands of stars can knock two black holes together. If a binary's black holes have randomly oriented spins, they likely formed in a globular cluster.

But what fraction of binaries form through one channel versus the other? The answer, astronomers believe, should lie in data, and particularly, measurements of black hole spins.

To date, astronomers have derived the spins of black holes in 69 binaries, which have been discovered by a network of gravitational-wave detectors including LIGO in the U.S., and its Italian counterpart Virgo. Each detector listens for signs of gravitational waves -- very subtle reverberations through space-time that are left over from extreme, astrophysical events such as the merging of massive black holes.

With each binary detection, astronomers have estimated the respective black hole's properties, including their mass and spin. They have worked the spin measurements into a generally accepted model of black hole formation, and found signs that binaries could have both a preferred, aligned spin, as well as random spins. That is, the universe could produce binaries in both galactic disks and globular clusters.

"But we wanted to know, do we have enough data to make this distinction?" Biscoveanu says. "And it turns out, things are messy and uncertain, and it's harder than it looks."

Spinning the data

In their new study, the MIT team tested whether the same data would yield the same conclusions when worked into slightly different theoretical models of how black holes form.

The team first reproduced LIGO's spin measurements in a widely used model of black hole formation. This model assumes that a fraction of binaries in the universe prefer to produce black holes with aligned spins, where the rest of the binaries have random spins. They found that the data appeared to agree with this model's assumptions and showed a peak where the model predicted there should be more black holes with similar spins.

They then tweaked the model slightly, altering its assumptions such that it predicted a slightly different orientation of preferred black hole spins. When they worked the same data into this tweaked model, they found the data shifted to line up with the new predictions. The data also made similar shifts in 10 other models, each with a different assumption of how black holes prefer to spin.

"Our paper shows that your result depends entirely on how you model your astrophysics, rather than the data itself," Biscoveanu says.

"We need more data than we thought, if we want to make a claim that is independent of the astrophysical assumptions we make," Vitale adds.

Just how much more data will astronomers need? Vitale estimates that once the LIGO network starts back up in early 2023, the instruments will detect one new black hole binary every few days. Over the next year, that could add up to hundreds more measurements to add to the data.

Read more at Science Daily

Rhino conservation in Nepal creates a burden for communities, infrastructure and other species, study warns

Efforts to conserve rhinos in Nepal have put a burden on communities, infrastructure and other wildlife in Nepal, a new study warns.

Successful anti-poaching and conservation campaigns in the country has resulted in increases in tourist numbers and rhino populations, but also increased incidences of human and animal casualties.

Locals from the area reported being proud to share spaces with rhinos, and wanting to live together with them, but were aware of the dangers. People who faced crop loss or fatality were overwhelmingly negative about living with rhinos; however, they still ‘strongly’ supported conservation legislation. They reported widescale dissatisfaction with the official compensation scheme for losses suffered.

The study, by Michelle Szydlowski, from the University of Exeter, is published in the Journal of Ecotourism and is the result of observations in Sauraha, Nepal. It describes the “disconnect” of people, especially tourists, wanting to “save” wild animals but also having a lack of consideration of their behaviour. The same people fail to consider the cost to other species who have to adapt to live with the rhinos.

Dr Szydlowski, who has worked in rhino conservation and elephant health and welfare in Nepal for the past decade, said: “Hand reared individuals bring in tourists, and while tourism may provide much-needed community income, it also creates a burden on existing infrastructure and may further commodify wildlife or encourage the conversion of wild habitats into tourist housing, restaurants, and shops.

“Nepal’s success in protecting native rhinos has led to increases in human-rhino conflict and changing perspectives on who has the greatest claim to anthropocentric spaces. As rhino and human populations continue to grow, there is a need to reconsider the impacts of tourism.

“The rhinos have moved beyond their physical and species boundaries to exist alongside humans in shared landscapes. Perhaps it is time to re-examine this parallel existence and find new ways to truly coexist within such communities.”

Dr Szydlowski interviewed members of the local community near Chitwan National Park, nature guides, tourists, National Trust for Nature Conservation (NTNC) staff, and government employees. She also collected information about the animals and how they had been cared for and kept in touch with interviewees for a year afterwards.

The presence of human infrastructure has not deterred rhinos – whether human-reared or wild - from using the farms, gardens, or streets of town as quick passageways. Locals post videos of passing rhinos on social media, hoping to encourage tourists to visit their shops and hotels.

Mostly wild rhinos pay little attention to shop or hotel guests as they pass through town, and most are not considered dangerous. Locals said males made a noise when they didn’t want to interact, but wild females, particularly with young, were more unpredictable.

Injuries and fatalities from wild rhino occur when humans enter the rhinos’ habitat, not the other way around. Since 1998, rhinos have been responsible for 55 human fatalities and 180 injuries in the area.

Indigenous human populations which once lived within the area now were forcibly relocated when governmental focus shifted toward wildlife conservation. These populations now face the greatest number of fatalities from negative encounters with wildlife.

Dr Szydlowski said: “Zones have been set aside for local use, they rarely produce enough to support the number of people living there, nor are local people involved in decision making or land-use planning. People living there reported feeling that they were ‘less important’ than local wildlife, and experience increasing competition with wildlife for land, forest products, and funding.

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Climate whiplash increased wildfires on California's west coast about 8,000 years ago

Scientists are trying to uncover and analyze evidence from the past in their search for a better assessment of future climate trends. In a joint international research project, researchers have been studying the effects of the sudden decrease in global temperatures that occurred about 8,200 years ago, the so-called 8.2-kiloyear event, with the help of mineral deposits present in White Moon Cave in Northern California. New indications show that oscillations between extreme wetness and aridity in California were closely linked with the occurrence of wildfires. The participating researchers from Johannes Gutenberg University Mainz (JGU) in Germany, Vanderbilt University in Nashville, USA, and Northumbria University in Newcastle upon Tyne in the UK have concluded that such events are likely to become more common in the face of human-induced climate change. The corresponding article has been published recently in Nature Communications.

Stalagmites as a valuable archive of climate data

Climate change and its effects on our seasons, water resources, vegetation, and soil have already become clearly apparent. The rate and intensity of wildfires in semi-arid regions, such as those in the west of North America, already exceed those that might be expected in view of the historical records.

To be able to predict future scenarios, it is helpful to better understand the climate of the past. There are readily datable climate archives that reach back many thousands of years that preserve traces of chemical compounds. These compounds provide insight into continental and regional climatic changes and the prevailing environmental conditions. One of the most easily datable and detailed climate archives of this kind is provided by various forms of mineral deposits, known as speleothems, which accumulate in caves. Stalagmites are of particular interest in this connection because of their uniform growth pattern.

By analyzing the content of two novel marker substances, i.e., levoglucosan and lignin oxidation products (LOPs), in a stalagmite, the team of researchers from Mainz, Nashville, and Newcastle have been able to reconstruct fire activity and vegetation composition in the California Coast Range during the 8.2-kiloyear event. This cold phase lasted several hundred years. Evidence of the event was first detected in the analysis of pollen in early Holocene deposits in the Swiss Alps and later also in ice cores obtained in Greenland. The results of further studies indicate that precipitation rates in western North America at this time were much more variable than usual. Erratic climate-related swings of this type are characteristic of a phenomenon called climate whiplash. Many scientists share the opinion that we will see more climate whiplash events as a consequence of global warming.

Hydroclimate fluctuations result in more fire activity and more woody vegetation

"The results we have now published suggest that both vegetation composition and wildfire activity were directly linked to this climate whiplash event," explained Julia Homann, a doctoral candidate in the research group of Professor Thorsten Hoffmann at Mainz University. Elevated concentrations of levoglucosan indicate increased fire activity, while altered LOP compositions represent a shift towards more tree-like vegetation during the 8.2-kiloyear event. The detected changes were direct consequences of a profound climate whiplash, in other words, stronger hydroclimate fluctuations.

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Genetic barriers, a warming ocean, and the uncertain future for an important forage fish

In the vast oceans, one would assume their inhabitants can travel far and wide and, as a result, populations of a species would mix freely. But this doesn't appear to be the case for a vital forage fish called the sand lance.

Sand lance are small schooling fish impressively rich in lipids, which makes them a fantastic and significant food source for at least 70 different species ranging from whales and sharks to seabirds, says UConn Associate Professor of Marine Sciences Hannes Baumann.

The Northern sand lance can be found from the waters off New Jersey all the way north to Greenland. Researchers, including Baumann and Ph.D. student Lucas Jones, were interested to see if sand lance constitute a massive, homogenous population, or whether there are genetically distinct groups. Their findings are published in the ICES Journal of Marine Science.

Baumann explains these are important questions to answer when considering conservation and sustainable management of the species, especially since the regions where sand lance live are warming faster than many areas of the planet due to climate change.

Sampling fish from such a broad range is no small task, but two years ago, Baumann and Jones began reaching out to other researchers to see if they had tissue samples to spare. Baumann credits the work to the international group of colleagues who contributed samples including co-authors from Canada and Greenland, and who helped sequence and analyze the data including co-authors from Cornell University.

In all, Baumann, Jones, and the team were able to sequence and analyze nearly 300 samples from a variety of locations across the sand lance's range using a technique called low-coverage whole genome sequencing. They also sequenced the first reference genome for sand lance.

In a nutshell, Baumann says they found an area on the Scotian Shelf, off the coast of Nova Scotia, where a genetic break occurs. The researchers distinguished two distinct groups, one north and one south of the divide, with parts of the genome differing quite dramatically -- namely on chromosomes 21 and 24. Without obvious physical barriers like a mountain range separating the groups, Baumann says it's logical to ask how these differences are possible.

"That is the scientific conundrum," says Baumann, and the answer, it appears, lies in the currents.

"When fish from the north reproduce and drift south, they are genetically less adapted to warmer southern waters, even if it's five or six degrees warmer in the winter, they are just not surviving," Baumann says. "These populations may be linked by the ocean currents, but the realized connectivity is basically zero."

This finding is a first for the sand lance, but it has been shown in other species such as lobsters, cod, and scallops, and this research adds further evidence to an apparent temperature divide at the Scotian Shelf, and helps demonstrate that temperature is an important factor in survival.

"Example after example shows that the ocean is not as homogeneous a place as expected, and there are all kinds of things that prevent that constant mixing,"Baumann says. "We found another striking example of that."

When researchers find adaptation in an environment where mixing is continuous, like in the ocean, Baumann says, the question is how it is possible that groups stay different, even though they are constantly encountering other genotypes. That is where powerful genomic methods, like the ones used in this paper, come in handy.

"Parts of the genome in many species have what we call a 'genetic inversion,' which means that the genes on the chromosome from one parent have a certain order and the genes on the same chromosome that come from the other parent that code for the same thing, and they're the same area, but they're flipped," Baumann says.

These inversions mean recombination cannot occur; therefore, the genes are passed down through the generations and play an important role in adaptation.

"We discovered on chromosomes 21 and 24 there are whole regions that are completely different and that is like the trademark signature of what we call an inversion because there's no recombination going on."

Baumann says that knowing there are genetic and ecological barriers on the Scotian Shelf is important, because with climate change, this barrier may move north and while that may be good news for southern fish, it's bad news for the fish currently there.

The researchers were also a little relieved in finding two clusters, because had there been many smaller clusters, it could make management and conservation more challenging, especially considering scenarios like the construction of offshore wind parks. Areas potentially well situated for wind turbines can also be habitats for sand lance, and construction disrupts habitats. If there were many, smaller population clusters, a single construction project could pose the risk of completely wiping out a cluster, whereas with more widely dispersed populations, though the local population may be temporarily disturbed, it will not be long before they are able to re-establish after construction is completed.

Baumann plans to focus further research on studying the genetic basis of the thermal divide.

"We want to make sure that this fish is productive and resilient, despite climate change, so we should make sure these areas where they are occurring are protected," Bauman says. "These decisions should include experts to ensure if there's an area that is very critical to sand lance, that any disturbance is temporary."

It isn't an unsolvable conflict, but it is something that we need to do, says Baumann, who also notes that it is possible that sand lance north of the thermal divide are already suffering more from warming because the region is warming faster.

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How selfish genes succeed

New findings from the Stowers Institute for Medical Research uncover critical insights about how a dangerous selfish gene -- considered to be a parasitic portion of DNA -- functions and survives. Understanding this dynamic is a valuable resource for the broader community studying meiotic drive systems.

A new study, published in PLoS Genetics on Dec. 7, 2022, reveals how a selfish gene in yeast uses a poison-antidote strategy that enables its function and likely has facilitated its long-term evolutionary success. This strategy is an important addition for scientists studying similar systems including teams that are designing synthetic drive systems for pathogenic pest control. Collective and collaborative advancement on understanding drive may one day lead to the eradication of pest populations that harm crops or even humans in the case of vector borne diseases.

"It's quite dangerous for a genome to encode a protein that has the capacity to kill the organism," said Stowers Associate Investigator SaraH Zanders, Ph.D. "However, understanding the biology of these selfish elements could help us build synthetic drivers to modify natural populations."

Drivers are selfish genes that can spread in a population at higher rates than most other genes, without benefiting the organism. Previous research from the Zanders Lab revealed that a driver gene in yeast, wtf4, produces poison protein capable of destroying all offspring. However, for a given parent cell's chromosome pair, drive is achieved when wtf4 is found only on one chromosome. The effect is a simultaneous rescue of only those offspring that inherit the drive allele, by delivering a dose of a very similar protein that counteracts the poison, the antidote.

Building upon this work, the study, led by former Predoctoral Researcher Nicole Nuckolls, Ph.D., and current Predoctoral Researcher Ananya Nidamangala Srinivasa in the Zanders Lab, discovered that differences in the timing of generating poison and antidote proteins from wtf4 and their unique distribution patterns within developing spores are fundamental to the drive process.

The team has developed a model they are continuing to investigate for how the poison acts to kill the spore -- the equivalent of a human egg or sperm in yeast. Their results indicate that poison proteins cluster together, potentially disrupting proper folding of other proteins required for the cell to function. Because the wtf4 gene encodes both poison and antidote, the antidote is very similar in form and groups together with the poison. However, the antidote has an extra part that appears to isolate the poison-antidote clusters by bringing them to the cell's garbage can, the vacuole.

To understand how selfish genes function during reproduction, the researchers looked at the beginning of spore formation and found poison protein expressed within all developing spores and the sac surrounding them, while the antidote protein was only seen in low concentration throughout the sac. Later in development, the antidote was enriched inside of the spores that inherited wtf4 from the parent yeast cell.

The researchers found that spores that inherited the driver gene manufactured additional antidote protein inside the spore to neutralize the poison and ensure their survival.

The team also discovered that a particular molecular switch that controls many other genes involved in spore formation also controls the expression of poison, but not antidote, from the wtf4 gene. The switch is essential for yeast reproduction and is inextricably linked to wtf4, helping to explain why this selfish gene is so successful at evading any attempts by the host to disable the switch.

"One of the reasons we are thinking these things have stuck around for so long -- they've used this sneaky strategy of exploiting the same essential switch that turns on yeast reproduction," said Nidamangala Srinivasa.

"If we could manipulate these DNA parasites to be expressed in mosquitoes and drive their destruction, it may be a way to control pest species," said Nuckolls.

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Curved spacetime in the lab

In a laboratory experiment, researchers from Heidelberg University have succeeded in realising an effective spacetime that can be manipulated. In their research on ultracold quantum gases, they were able to simulate an entire family of curved universes to investigate different cosmological scenarios and compare them with the predictions of a quantum field theoretical model.

According to Einstein's Theory of Relativity, space and time are inextricably connected. In our Universe, whose curvature is barely measurable, the structure of this spacetime is fixed. In a laboratory experiment, researchers from Heidelberg University have succeeded in realising an effective spacetime that can be manipulated. In their research on ultracold quantum gases, they were able to simulate an entire family of curved universes to investigate different cosmological scenarios and compare them with the predictions of a quantum field theoretical model. The research results were published in Nature.

The emergence of space and time on cosmic time scales from the Big Bang to the present is the subject of current research that can only be based on the observation of our single Universe. The expansion and curvature of space are essential to cosmological models. In a flat space like our current Universe, the shortest distance between two points is always a straight line. "It is conceivable, however, that our Universe was curved in its early phase. Studying the consequences of a curved spacetime is therefore a pressing question in research," states Prof. Dr Markus Oberthaler, a researcher at the Kirchhoff Institute for Physics at Heidelberg University. With his "Synthetic Quantum Systems" research group, he developed a quantum field simulator for this purpose.

The quantum field simulator created in the lab consists of a cloud of potassium atoms cooled to just a few nanokelvins above absolute zero. This produces a Bose-Einstein condensate -- a special quantum mechanical state of the atomic gas that is reached at very cold temperatures. Prof. Oberthaler explains that the Bose-Einstein condensate is a perfect background against which the smallest excitations, i.e. changes in the energy state of the atoms, become visible. The form of the atomic cloud determines the dimensionality and the properties of spacetime on which these excitations ride like waves. In our Universe, there are three dimensions of space as well as a fourth: time.

In the experiment conducted by the Heidelberg physicists, the atoms are trapped in a thin layer. The excitations can therefore only propagate in two spatial directions -- the space is two-dimensional. At the same time, the atomic cloud in the remaining two dimensions can be shaped in almost any way, whereby it is also possible to realise curved spacetimes. The interaction between the atoms can be precisely adjusted by a magnetic field, changing the propagation speed of the wavelike excitations on the Bose-Einstein condensate.

"For the waves on the condensate, the propagation speed depends on the density and the interaction of the atoms. This gives us the opportunity to create conditions like those in an expanding universe," explains Prof. Dr Stefan Flörchinger. The researcher, who previously worked at Heidelberg University and joined the University of Jena at the beginning of this year, developed the quantum field theoretical model used to quantitatively compare the experimental results.

Using the quantum field simulator, cosmic phenomena, such as the production of particles based on the expansion of space, and even the spacetime curvature can be made measurable. "Cosmological problems normally take place on unimaginably large scales. To be able to specifically study them in the lab opens up entirely new possibilities in research by enabling us to experimentally test new theoretical models," states Celia Viermann, the primary author of the "Nature" article. "Studying the interplay of curved spacetime and quantum mechanical states in the lab will occupy us for some time to come," says Markus Oberthaler, whose research group is also part of the STRUCTURES Cluster of Excellence at Ruperto Carola.

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