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.

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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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Dinosaur teeth reveal what they didn't eat

Scratches on dinosaur teeth could reveal what they really ate. For the first time, dental microwear texture analysis (DMTA) has been used to infer the feeding habits of large theropods, including Allosaurus and T. rex. By taking 3D images of individual teeth and analyzing the pattern of marks scratched into them, researchers could reason which dinosaurs may have frequently crunched on hard bone and which may have regularly eaten softer foods and prey. This technique opens up a new avenue of research for paleontology, helping us to better understand not only dinosaurs themselves but also the environment and communities in which they lived.

From Fantasia to Jurassic Park, the T. rex is seen as a terrifying apex predator that would chase down its prey and crunch on it whole. But how much did this iconic dinosaur actually chow down on bones? And what about other predatory dinosaurs that existed long before it?

Researchers from the University of Tokyo, in collaboration with teams from the University of Mainz and the University of Hamburg in Germany, have used dental microwear texture analysis (DMTA), a scanning technique to examine topographical dental wear and tear in microscopic detail, on individual dinosaur teeth from more than 100 million years ago to better understand what they may have eaten. "We wanted to test if we could use DMTA to find evidence of different feeding behaviors in tyrannosaurids (from the Cretaceous period, 145 million to 66 million years ago) compared to the older Allosaurus (from the Jurassic period, 201 million to 145 million years ago), which are both types of theropods," explained postdoctoral fellow Daniela Winkler from the Graduate School of Frontier Sciences. "From other research, we already knew that tyrannosaurids can crack and feed on bones (from studies of their feces and bite marks on bone). But allosaurs are much older and there is not so much information about them."

DMTA has mainly been used to study mammal teeth, so this is the first time it was used to study theropods. The same research team from the University of Tokyo also recently pioneered a study on DMTA in Japanese sauropod dinosaurs, famous for their long necks and tails. A high-resolution 3D image was taken of the tooth surface at a very small scale of 100 micrometers (one-tenth of a millimeter) by 100 micrometers in size. Up to 50 sets of surface texture parameters were then used to analyze the image, for example, the roughness, depth and complexity of wear marks. If the complexity was high, i.e., there were different-sized marks which overlaid each other, this was associated with hard object feeding, such as on bone. However, if the complexity was low, i.e., the marks were more arranged, of a similar size and not overlapping, this was associated with soft object feeding, like meat.

In total, the team studied 48 teeth, 34 from theropod dinosaurs and 14 from crocodilians (modern crocodiles and alligators), which were used as a comparison. The team was able to study original fossilized teeth and take high-resolution silicon molds, thanks to loans provided by natural history museums in Canada, the U.S., Argentina and Europe. "We actually started dental microwear research of dinosaurs in 2010," said Lecturer Mugino Kubo from the Graduate School of Frontier Sciences. "My husband, Dr. Tai Kubo, and I had started collecting dental molds of dinosaurs and their contemporaries in North and South Americas, Europe, and of course Asia. Since Daniela joined my lab, we utilized these molds to make a broader comparison among carnivorous dinosaurs."

"It was especially challenging to carry out this research during the pandemic," said Winkler "as we rely on being able to gather samples from international institutions. The sample size might not be so large this time, but it is a starting point."

Winkler says what they found surprising was that they didn't find evidence of much bone crushing behavior in either Allosaurus or tyrannosaurids, even though they know that tyrannosaurids ate bone. There may be several reasons for this unexpected outcome. It could be that although Tyrannosaurus was able to eat bone, it was less commonly done than previously thought. Also, the team had to use well-preserved teeth, so it might be that extremely damaged teeth that were excluded from this study were in such a condition because those animals fed more on bone.

Something the team did find with both the dinosaurs and crocodilians was a noticeable difference between juveniles and adults. "We studied two juvenile dinosaur specimens (one Allosaurus and one tyrannosaurid) and what we found was a very different feeding niche and behavior for both compared to the adults. We found that there was more wear to juvenile teeth, which might mean that they had to more frequently feed on carcasses because they were eating leftovers," explained Winkler. "We were also able to detect different feeding behavior in juvenile crocodilians; however, this time it was the opposite. Juvenile crocodilians had less wear on their teeth from eating softer foods, perhaps like insects, while adults had more dental wear from eating harder foods, like larger vertebrates."

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