Ultracool dwarf binary stars break records

Northwestern University and the University of California San Diego (UC San Diego) astrophysicists have discovered the tightest ultracool dwarf binary system ever observed.

The two stars are so close that it takes them less than one Earth day to revolve around each other. In other words, each star's "year" lasts just 17 hours.

The newly discovered system, named LP 413-53AB, is composed of a pair of ultracool dwarfs, a class of very low-mass stars that are so cool that they emit their light primarily in the infrared, making them completely invisible to the human eye. They are nonetheless one of the most common types of stars in the universe.

Previously, astronomers had only detected three short-period ultracool dwarf binary systems, all of which are relatively young -- up to 40 million years old. LP 413-53AB is estimated to be billions of years old -- similar age to our sun -- but has an orbital period that is at least three times shorter than the all ultracool dwarf binaries discovered so far.

The research was published on March 1 in the Astrophysical Journal Letters.

"It's exciting to discover such an extreme system," said Chih-Chun "Dino" Hsu, a Northwestern astrophysicist who led the study. "In principle, we knew these systems should exist, but no such systems had been identified yet."

Hsu is a postdoctoral researcher in Northwestern's Center for Interdisciplinary Exploration and Research in Astrophysics(CIERA). He began this study while a Ph.D. student at UC San Diego, where he was advised by Professor Adam Burgasser.

The team first discovered the strange binary system while exploring archival data. Hsu developed an algorithm that can model a star based on its spectral data. By analyzing the spectrum of light emitted from a star, astrophysicists can determine the star's chemical composition, temperature, gravity and rotation. This analysis also shows the star's motion as it moves toward and away from the observer, known as radial velocity.

When examining the spectral data of LP 413-53AB, Hsu noticed something strange. Early observations caught the system when the stars were roughly aligned and their spectral lines overlapped, leading Hsu to believe it was just one star. But as the stars moved in their orbit, the spectral lines shifted in opposite directions, splitting into pairs in later spectral data. Hsu realized there were actually two stars locked into an incredibly tight binary.

Using powerful telescopes at the W.M. Keck Observatory, Hsu decided to observe the phenomenon for himself. On March 13, 2022, the team turned the telescopes toward the constellation Taurus, where the binary system is located, and observed it for two hours. Then, they followed up with more observations in July, October and December as well as January 2023.

"When we were making this measurement, we could see things changing over a couple of minutes of observation," Burgasser said. "Most binaries we follow have orbit periods of years. So, you get a measurement every few months. Then, after a while, you can piece together the puzzle. With this system, we could see the spectral lines moving apart in real time. It's amazing to see something happen in the universe on a human time scale."

The observations confirmed what Hsu's model predicted. The distance between the two stars is about 1% of the distance between the Earth and the sun. "This is remarkable, because when they were young, something like 1 million years old, these stars would have been on top of each other," said Burgasser.

The team speculates that the stars either migrated toward each other as they evolved, or they could have come together after the ejection of a third -- now lost -- stellar member. More observations are needed to test these ideas.

Hsu also said that by studying similar star systems researchers can learn more about potentially habitable planets beyond Earth. Ultracool dwarfs are much fainter and dimmer than the sun, so any worlds with liquid water on their surfaces -- a crucial ingredient to form and sustain life -- would need to be much closer to the star. However, for LP 413-53AB, the habitable zone distance happens to be the same as the stellar orbit, making it impossible to form habitable planets in this system.

"These ultracool dwarfs are neighbors of our sun," Hsu said. "To identify potentially habitable hosts, it's helpful to start with our nearby neighbors. But if close binaries are common among ultracool dwarfs, there may be few habitable worlds to be found."

To fully explore these scenarios, Hsu, Burgasser and their collaborators hope to pinpoint more ultracool dwarf binary systems to create a full data sample. New observational data could help strengthen theoretical models for binary-star formation and evolution. Until now, however, finding ultracool binary stars has remained a rare feat.

Read more at Science Daily

Most detailed geological model reveals Earth's past 100 million years

Climate, tectonics and time combine to create powerful forces that craft the face of our planet. Add the gradual sculpting of the Earth's surface by rivers and what to us seems solid as rock is constantly changing.

However, our understanding of this dynamic process has at best been patchy.

Scientists today have published new research revealing a detailed and dynamic model of the Earth's surface over the past 100 million years.

Working with scientists in France, University of Sydney geoscientists have published this new model in the journal Science.

For the first time, it provides a high-resolution understanding of how today's geophysical landscapes were created and how millions of tonnes of sediment have flowed to the oceans.

Lead author Dr Tristan Salles from the University of Sydney School of Geosciences, said: "To predict the future, we must understand the past. But our geological models have only provided a fragmented understanding of how our planet's recent physical features formed.

"If you look for a continuous model of the interplay between river basins, global-scale erosion and sediment deposition at high resolution for the past 100 million years, it just doesn't exist.

"So, this is a big advance. It's not only a tool to help us investigate the past but will help scientists understand and predict the future, as well."

Using a framework incorporating geodynamics, tectonic and climatic forces with surface processes, the scientific team has presented a new dynamic model of the past 100 million years at high resolution (down to 10 kilometres), broken into frames of a million years.

Second author Dr Laurent Husson from Institut des Sciences de la Terre in Grenoble, France, said: "This unprecedented high-resolution model of Earth's recent past will equip geoscientists with a more complete and dynamic understanding of the Earth's surface.

"Critically, it captures the dynamics of sediment transfer from the land to oceans in a way we have not previously been able to."

Dr Salles said that understanding the flow of terrestrial sediment to marine environments is vital to comprehend present-day ocean chemistry.

"Given that ocean chemistry is changing rapidly due to human-induced climate change, having a more complete picture can assist our understanding of marine environments," he said.

The model will allow scientists to test different theories as to how the Earth's surface will respond to changing climate and tectonic forces.

Further, the research provides an improved model to understand how the transportation of Earth sediment regulates the planet's carbon cycle over millions of years.

"Our findings will provide a dynamic and detailed background for scientists in other fields to prepare and test hypotheses, such as in biochemical cycles or in biological evolution."

Read more at Science Daily

AI draws most accurate map of star birthplaces in the Galaxy

Osaka Metropolitan University scientists identified about 140,000 molecular clouds in the Milky Way Galaxy from large-scale data of carbon monoxide molecules, observed in detail by the Nobeyama 45-m radio telescope. Using artificial intelligence, the researchers estimated the distance of each of these molecular clouds to determine their size and mass, successfully mapping the distribution of the molecular clouds in the Galaxy in the most detailed manner to date.

Stars are formed by molecular gas and dust coalescing in space. These molecular gases are so dilute and cold that they are invisible to the human eye, but they do emit faint radio waves that can be observed by radio telescopes.

Observing from Earth, a lot of matter lies ahead and behind these molecular clouds and these overlapping features make it difficult to determine their distance and physical properties such as size and mass.

So, even though our Galaxy, the Milky Way, is the only galaxy close enough to make detailed observations of molecular clouds in the whole universe, it has been very difficult to investigate the physical properties of molecular clouds in a cohesive manner from large-scale observations.

A research team led by Dr. Shinji Fujita from the Osaka Metropolitan University Graduate School of Science, identified about 140,000 molecular clouds in the Milky Way Galaxy, which are areas of star formation, from large-scale data of carbon monoxide molecules, observed in detail by the Nobeyama 45-m radio telescope. Using artificial intelligence, the research team estimated the distance of each of these molecular clouds, determined their size and mass and successfully mapped their distribution, covering the first quadrant of the Galactic plane, in the most detailed manner to date.

From Science Daily

Wisconsin cave holds tantalizing clues to ancient climate changes, future shifts

Even in their dark isolation from the atmosphere above, caves can hold a rich archive of local climate conditions and how they've shifted over the eons. Formed over tens of thousands of years, speleothems -- rock formations unique to caves better known as stalagmites and stalactites -- hold secrets to the ancient environments from which they formed.

A newly published study of a stalagmite found in a cave in southern Wisconsin reveals previously undetected history of the local climate going back thousands of years. The new findings provide strong evidence that a series of massive and abrupt warming events that punctuated the most recent ice age likely enveloped vast swaths of the Northern Hemisphere.

The research, conducted by a team of scientists at the University of Wisconsin-Madison, appears March 2 in the journal Nature Geoscience. It's the first study to identify a possible link between ice age warm-ups recorded in the Greenland ice sheet -- known as Dansgaard-Oeschger events -- and climate records from deep within the interior of central North America.

"This is the only study in this area of the world that is recording these abrupt climate events during the last glacial period," says Cameron Batchelor, who led the analysis while completing her PhD at UW-Madison. Batchelor is now a postdoctoral fellow with the National Science Foundation working at the Massachusetts Institute of Technology.

The study is based on an exceptionally detailed chemical and physical analysis of a stalagmite that formed in the Cave of the Mounds, a tourist attraction and educational destination.

"At Cave of the Mounds our mission is to interpret this geologic wonder for our many annual visitors," says Joe Klimczak, general manager of the cave, which is a designated national natural landmark. "We are thrilled to deepen our understanding of the cave thanks to this world-class research and very exciting results."

The stalagmite Batchelor and her team analyzed grew extremely slowly -- taking roughly 20,000 years to reach the length of a human pinky finger.

The finger-length subterranean rock formed from a complex process that began in the sky. Water that originally fell as precipitation from the atmosphere soaked into the ground and percolated through soil and cracks in bedrock, dissolving tiny bits of limestone along the way. Some of that dissolved limestone was then left behind as countless drips of water fell from the ceiling of Cave of the Mounds, gradually accumulating into thousands of exceedingly thin layers of a mineral called calcite.

"And because those calcite layers are formed from that original precipitation, they're locking in the oxygen in the H2O originating from that precipitation," says Batchelor.

Therein lies the key to reconstructing an ancient climate record from a small, otherwise unremarkable rock. The oxygen trapped in the calcite exists in a couple varieties -- known as isotopes -- that scientists can use to glean information about the environmental conditions present during the precipitation events that formed it. That includes the temperature and possible sources of rain and snow that fell atop the Cave of the Mounds over thousands of years.

Batchelor's team used a specialized imaging technique that allowed them to identify layers within the stalagmite representing annual growth bands -- much like how tree rings record a season's worth of growth. Using another technique, they identified the isotopes in the tiny layers, revealing that present-day southern Wisconsin experienced a number of very large average temperature swings of up to 10 C (or about 18 F) between 48,000 and 68,000 years ago. Several of the temperature swings occurred over the course of around a decade.

While the dating information is not precise enough to definitively tie the temperature swings to the Dansgaard-Oeschger events recorded in Greenland ice cores, the researchers can say with confidence they occurred within similar timeframes. The team also performed climate simulations that bolstered the hypothesis that warming events occurred tens of thousands of years ago in the region of North America that includes present-day Wisconsin, and that the climate records from Cave of the Mounds and the Greenland ice sheet are indeed linked.

This potential link is exciting for Batchelor because it offers a climate story about central North America that has so far gone untold. Previous research from the mid-continent has not resolved signals of these large temperature swings, also called excursions.

"One theory was that the mid-continent is relatively immune to abrupt climate changes, and that maybe that's because it's surrounded by landmass, and there's some type of buffering happening," says Batchelor. "However, when we went and measured, we saw these really large excursions, and we were like, 'Oh, no, something is definitely happening.'"

That something -- a rapidly changing climate -- is unfolding yet again today, thanks to humans and our use of fossil fuels. Batchelor says she hopes her work in Wisconsin, and now a cave in the Canadian subarctic that she is studying for her postdoc, helps fill a big data gap about the history and potential future of abrupt climate changes in the mid-continent of North America.

Read more at Science Daily

Insights into the evolution of the sense of fairness

A sense of fairness has long been considered purely human -- but animals also react with frustration when they are treated unequally by a person. For instance, a well-known video shows monkeys throwing the offered cucumber at their trainer when a conspecific receives sweet grapes as a reward for the same task. Meanwhile, researchers have observed similarly frustrated reactions to unfair rewards in wolves, rats and crows. However, researchers still debate the reasons for this behavior: Does the frustration really stem from a dislike of unequal treatment, or is there another explanation?

In a study with long-tailed macaques (Macaca fascicularis), researchers at the German Primate Center -- Leibniz Institute for Primate Research (DPZ) have now confirmed an alternative explanatory approach in a collaborative project involving the Departments of Cognitive Ethology and Neurobiology. The team around Rowan Titchener, PhD student at the Georg-August-Universität Göttingen and researcher in the Department of Cognitive Ethology at the DPZ, showed that long-tailed macaques rejected an inferior reward more frequently if it is selected and allocated by a person. In contrast, if the reward is provided by an automatic feeder, they accept it. The researchers conclude that the monkeys refuse the reward out of social disappointment towards the experimenter -- and not because they feel that they are at a disadvantage compared to a conspecific. (Royal Society Open Science).

Humans have a strong sense of equity. If we believe that resources are being unfairly or wrongly distributed, we make this clear -- with protest. This controlling behavior promotes successful cooperation and partly explains why cooperation has been a winning strategy in human evolution.

Equal effort, same reward

However, not only humans protest when the same performance is rewarded differently for no apparent reason. Many animals are likewise dissatisfied with a reward that is perceived as comparatively inferior and react in a frustrated way. The characteristic behavioral patterns can be reliably reproduced in experiments across various species of birds, rodents and monkeys. The interpretation of this protest behavior, on the other hand, is controversial among researchers. If the animals' frustration stemmed from a comparison of their own reward with that of their conspecific, this would indicate an abstract understanding of equal treatment.

The root of disappointment

In the present study, the researchers tested three alternative explanations for protest behavior following unequal treatment. The first hypothesis invokes "inequity aversion" and presupposes social comparison with conspecifics and a sense of fairness. This is based on the idea that the pattern of rewards is compared between oneself and others so that it may be perceived as unfair. The second hypothesis, "food expectation," assumes the visibility of the attractive food as a trigger for frustration. Thus, if a high-quality reward is visible, the animal expects to receive it. The third hypothesis is based on "social disappointment" about the trainer's decision to provide an inferior reward. Behind this stands an expectation to be rewarded in the best possible way by the responsible human.

Disappointing human

The results of the current study on long-tailed macaques are in line with a previously published chimpanzee study. Rowan Titchener, lead author of the study, states: "The animals' response patterns are best explained by frustration with the human trainer's decisions. Thus, the current results speak for the third hypothesis, based on social disappointment." This interpretation is supported in particular by the fact that the long-tailed macaques accepted an inferior reward from an automatic feeder more often than from a human.

Experimental setup

The researchers confronted the monkeys with four different scenarios in the experiment. The procedure was always the same: The activation of a lever was followed by the reward of low-quality food, which was brought within reach by a small conveyor belt. High-quality rewards were displayed, but remained out of reach. The experimental design was varied in two ways: Firstly, either a human provided the reward, or it was administered by an automatic feeder; secondly, the animal was either alone, or a conspecific solved the same task within sight, but received higher-quality rewards.

Clear result

The monkeys almost never refused their reward when it was provided by the automatic feeder -- but did so in more than 20 percent of the experiments in which a human offered the food. This behavioural pattern is consistent with social disappointment with the human who decides to give them the inferior reward. "The monkeys have no social expectations of a vending machine and are therefore not disappointed," Titchener explains.

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Case study of rare, endangered tortoise highlights conservation priorities for present, future World Wildlife Days

Though wildlife trafficking has been effectively disrupted since the first World Wildlife Day -- established 50 years ago today via the 1973 Convention on International Trade in Endangered Species (CITES) of Wild Fauna and Flora -- a newly published case study on one of the world's rarest tortoise species, the ploughshare tortoise, highlights how much room for improvement still exists.

In a new paper published in the Proceedings of the National Academies of the Sciences, University of Maryland Associate Professor Meredith Gore and her coauthors -- Babson College's Emily Griffin, Bistra Dilkina and Aaron Ferber from the University of Southern California, Michigan State University's Stanley E. Griffis, the University of Alabama's Burcu B. Keskin, and John Macdonald from Colorado State University -- detail a 2018 effort to map ploughshare tortoises' location within and around Soalala, Madagascar; nearby villages; known trafficking pathways and transit routes; and the amount of trafficking risk associated with each of those areas. The group of approximately 50 stakeholders also shared more qualitative information that might play a role in poachers' trafficking process, such as paths of cultural and spiritual significance, tides' influence on decision-making; and where poachers met to plan their activities.

This information was drawn onto a clear, plastic sheet that was laid across a color-based map of the region. That information was then digitized into a geographic information system, creating what the researchers' called a "mess" that nevertheless revealed novel information for the effective targeting of those ploughshare tortoise trafficking networks.

"Our science team used a cross-disciplinary and cross-sectoral approach to think about, measure, and analyze data," explains Gore. "Not only were we able to shift the data landscape to clarify how important water routes are to the resilience of the illicit supply chain, we were able to normalize technical spatial data with insights from traditionally marginalized voices -- women."

Gore and her co-authors argue that if a process like this were to be paired with the latest advancements in computational science, operations engineering, and supply chain management, together, researchers could dramatically disrupt wildlife trafficking networks, and thereby conserve more animals, like the ploughshare tortoise, who are already on the brink of extinction.

"As we celebrate World Wildlife Day, our recent work highlights the urgent need for interdisciplinary collaboration to address the complex global issue of wildlife trafficking," says Bistra Dilkina, an associate professor of computer science and industrial and systems engineering at the University of Southern California. "I feel privileged to have the opportunity to work with a trans-disciplinary team to synthesize a roadmap of how our different disciplines can work together to fight illegal wildlife trafficking and trade. In particular, I am excited to think deeply about the advantages that data-driven approaches in machine learning and optimization can bring to this important endeavor."

Looking to the future, the researchers believe that with increased interdisciplinary collaborations, conservationists may one day be able to predict which path a trafficker will take, target areas where locals could undergo trainings and be empowered to play a part in preventing wildlife trafficking, better allocate limited resources to have the greatest interventional impact, and more.

Read more at Science Daily

Resurrected supernova provides missing-link

Astronomers have discovered a supernova exhibiting unprecedented rebrightening at millimeter wavelengths, providing an intermediate case between two types of supernovae: those of solitary stars and those in close-binary systems.

Many massive stars end their lives in a catastrophic explosion known as a supernova (SN). Supernovae increase rapidly in brightness, and then fade over the course of several months.

Astronomers have long known that the presence or absence of a close binary companion can affect the evolution of massive stars. In a close binary system, gravitational interactions with the binary companion will strip large amounts of material from the SN progenitor long before the final explosion. In these cases, the progenitor will be quiet up until the time of the actual SN. On the other hand, in the case of an SN progenitor with no binary companion or a distant companion, leading up to the SN explosion the progenitor will keep most of its initial mass.

Of course smart alecs will ask, "What happens when the binary is not too close and not too distant?" Not just smart alecs, astronomers also wanted to know. The break came when an international research team, led by Keiichi Maeda (Professor at the Graduate School of Science, Kyoto University) and Tomonari Michiyama (ALMA Joint Postdoctoral Fellow at the Graduate School of Science, Osaka University), used ALMA (The Atacama Large Millimeter/submillimeter Array) to monitor a supernova known as SN 2018ivc as it dimmed for about 200 days after the initial explosion. The results showed that SN 2018ivc was an unusual object, so the team decided to check up on it again, at about 1000 days after the explosion. They found that the object was actually rebrightening, the first time this phenomenon had ever been observed in millimeter wavelength radiation.

Read more at Science Daily

Waxing and waning of environment influences hominin dispersals across ancient Iran

A world-first model of paleoclimate and hydrology in Iran has highlighted favourable routes for Neanderthals and modern human expansions eastwards into Asia.

Published in PLOS ONE, the findings reveal for the first time that multiple humid periods in ancient Iran led to the expansions of human populations, opening dispersal route across the region, and the possible interactions of species such as Neanderthals and our own Homo sapiens.

Professor Michael Petraglia, a key researcher in the study, said historic humid periods resulted in massive changes to ecosystems and led the team to identify large lakes in areas that were formerly deserts.

"Conversely, during glacial periods this increased aridity would have led to the expansion of deserts, led to contractions, and the isolation of hominin populations," said Professor Petraglia, who is the Director of Griffith's Australian Research Centre for Human Evolution.

"This cycle of wetting and drying is shown for the first time in Iran."

The research team, led by PhD candidate Mohammad Javad Shoaee from the Max Planck Institute for Geoanthropology in Germany, found that during Marine Isotope Stage (MIS) 5, a warm, humid period beginning roughly 130,000 years ago, lakes and rivers enabled two pathways for human groups.

One was a northern route through the Alborz and Kopet Dagh Mountains and north of the Dasht-I Kavir desert. The other route, first identified here, ran south along the Zagros Mountains before extending eastwards towards Pakistan and Afghanistan.

The researchers also found evidence for a potential northern route during MIS 3, beginning about 57,000 years ago, which, given artifacts attributed to multiple tool making groups, could have permitted interactions between modern humans and Neanderthals.

"These findings highlight the importance of Iran for our species' dispersals out of Africa and ultimately around the globe," said Professor Petraglia.

"As in other regions long considered too arid for early human occupations, such as the Arabian Peninsula, recent palaeoclimatic research is changing how we understand the human story and the role that changing climates have played."

"We recognised a new southern route along the Zagros Mountains and extending eastwards towards Pakistan and Afghanistan. We found evidence for a potential northern route during MIS 3, which would have permitted hominin movements and species interactions in Southwest Asia," Shoaee said.

To find out how human groups made their way into Iran, the team developed the first spatially comprehensive, high resolution palaeohydrological model for Iran.

They then compared their model, which showed when and where water was available, to the distribution of previously documented archaeological sites.

The result was a clear relationship between the availability of water and the evidence of human presence.

Not only does the current study help to explain the presence of previously documented sites, it also serves as a guide for future archaeological surveys in the region.

"Our paleohydrological analyses identified 145,354km of rivers and 115 paleolakes calculated from 6380 paleolake deposits. Only a handful of these paleolakes have so far been studied," Shoaee said.

Read more at Science Daily

Deforestation in the tropics linked to a reduction in rainfall

Deforestation is resulting in reduced rainfall across large parts of the tropics, according to new research.

People living in tropical forest communities have often complained that the climate gets hotter and drier once trees are cleared but until now, scientists have not been able to identify a clear link between the loss of tree cover and a decline in rainfall.

A research team at the University of Leeds combined satellite data of deforestation and rainfall to show that the loss of tree cover in the tropics over the last 14 years was associated with reductions in rainfall.

They estimate that by the end of the century, if the rate of deforestation in the Congo was to continue, rainfall in the region could be reduced by between 8% and 12%, with a major impact on biodiversity, farming and could threaten the viability of the Congo forests, which are among the world's largest stores of carbon.

Callum Smith, a doctoral researcher in the School of Earth and Environment at Leeds and the lead author in the study, said the investigation provides "compelling evidence" to protect forests from uncontrolled clearing.

He added: "Tropical forests play a critical role in the hydrological cycle through helping to maintain local and regional rainfall patterns. The reduction in rainfall caused by tropical deforestation will impact people living nearby through increased water scarcity and depressed crop yields.

"Tropical forests themselves rely on moisture to survive and remaining areas of forest will be impacted by a drier climate."

The research paper -- Tropical deforestation causes large reductions in observed precipitation -- is published today (Wed, March 1st) in the scientific journal Nature.

The researchers looked at the impact of forest loss in three areas of the tropics -- the Amazon, Congo and Southeast Asia -- which have all experienced rapid land-use changes. The study involved analysis of satellite observations from 2003 to 2017, to identify locations where forests had been cleared. Rainfall data in these areas, also measured by satellites, was compared to rainfall from nearby locations where forests had not been lost.

Forest loss linked to rainfall loss

The study revealed that tropical forest loss caused reductions in rainfall throughout the year, including in the dry season when any further drying will have the biggest ramifications on plant and animal ecosystems. The greatest absolute decline in precipitation was seen in the wet season with up to a 0.6 mm a month reduction in rainfall for every percentage point loss of forest cover.

Writing in the paper, the researchers warn that climate change will lead to increased drought and that will be exacerbated by continued deforestation.

Link between forest cover and rainfall

It is believed the loss of tree cover disrupts the process where moisture from leaves -- through a mechanism called evapotranspiration -- is returned to the atmosphere where it eventually forms rain clouds.

As well as impacting natural ecosystems, a reduction in rainfall would be detrimental to agriculture and hydropower plants. That would have a strong impact both on the healthy functioning of the forests and on local communities.

The research team say, on average, crop yields declined by 0.5% for every 1% reduction in rainfall.

Tropical forests sustain rainfall

Professor Dominick Spracklen, from the School of Earth and Environment at Leeds who supervised the project, said: "Local people living near deforested regions often report a hotter and drier climate after the forests are cleared. But until now this effect had not been seen in rainfall observations.

"The study shows the critical importance of tropical forests in sustaining rainfall. Although there have been efforts to halt deforestation, the loss of forest cover in the tropics has continued. There needs to be renewed efforts to stop forests being lost and to regenerate lost and degraded areas."

The scientists warn that a decline in rainfall has a negative impact on biodiversity, increases the risk of forest fires and reduces carbon sequestration, where nature removes carbon from the atmosphere and stores it.

Read more at Science Daily

On a warming planet, these Arctic geese rapidly found (and shared) a new migratory route

As the planet warms, animals that breed in the Arctic are at particular risk. But a new study reported in Current Biology on March 1 offers some encouraging news: in an apparent reaction to pressures along their former migratory route, a population of Arctic geese has rapidly adjusted, forming a new migration route and breeding location almost 1,000 kilometers from their original stomping grounds.

What's more, it appears the new route has caught on with other geese and even birds of other species via cultural transmission (social learning). As such, the new population already has grown to as many as 4,000 individuals.

"It is extremely fascinating to witness such rapid evolution of new breeding grounds and migratory route by a bird species that is regarded as being very traditional in its behavior and site use," said Jesper Madsen of Aarhus University in Denmark. "It gives some hope for 'ecological rescue' at times of very radical environmental changes due to climate change and, more broadly, global change."

"We observe a new distinct population of birds in the making in real time," he added. "This is very rare to observe. The speed of the development is astonishing."

Madsen's team has been studying Norway's Svalbard population of pink-footed geese for more than 35 years. They've kept tabs on their population size and demographic variables, using a systematic marking and resighting program. About 20 years ago, they started getting reports of geese turning up on migration in Sweden and Finland, which were confirmed as members of the Svalbard population.

To learn more, Madsen went to Oulu, Finland, in the spring of 2018 and 2019 with his goose-catching team from Denmark as well as Dutch and Finnish partners. Their hope was to catch and tag some pink-footed geese with GPS tags. They wanted to know where these geese were going, and they got an unexpected answer.

"It was a real surprise to see that half of the marked individuals in Oulu migrated northeast to Novaya Zemlya in north Russia," Madsen says. "From the tagging information we could not only follow their new path but also got indications that females were breeding there. This site is around 1,000 kilometers east of the Svalbard breeding grounds.

"It was also cool to observe that geese from the traditional flyway have turned up on the new route and seemed to have switched. Hence, social learning and following individuals from the new route has been an important phenomenon, which also explains how this development could be so fast."

With their new report, they've now documented an abrupt formation of a new migration route and population for the Arctic geese over the course of 10 to 15 years. The population has grown over time due to successful breeding and high survival rates combined with continued immigration of geese from the old route to the new one.

Their ability to live in Novaya Zemlya has apparently been aided by warming in the area, they say. While the new population is not genetically or demographically isolated yet, they note that it already now qualifies as a separate population.

The new route does have some disadvantages, Madsen says. For instance, it's longer. But they suspect the benefits of the new route and grounds outweigh any downsides. The findings in geese show the importance of social learning on a changing planet, Madsen notes, especially in social animals including birds but perhaps also hoofed ungulates, wolves, and whales.

"At this time, when climate change and other human activities threaten many species, not least the Arctic ones, social learning can be a behavior that can provide advantages to avoid some negative impacts, at least in the short term," Madsen says.

The researchers say they hope one day to observe the geese in their new breeding grounds in Russia. For now, they'll keep an eye on the future development of the new population using GPS-tracking devices and remote sensing of the new environment.

Read more at Science Daily

New NASA DART data prove viability of asteroid deflection as planetary defense strategy

NASA's Double Asteroid Redirection Test (DART) was Earth's first attempt at launching a spacecraft to intentionally collide with and deflect an asteroid as a planetary defense technique. On September 26, 2022, the DART spacecraft collided with a small asteroid moon called Dimorphos, which orbits a larger asteroid called Didymos. Neither asteroid posed a threat to Earth, but they represented similar celestial bodies that could one day approach and endanger the planet.

In four papers published in the journal Nature on March 1, 2023, the DART team -- which includes University of Maryland astronomers -- detailed DART's successful impact, the possible physics behind the collision, observations of the resulting debris ejected from the asteroid and calculations of Dimorphos' orbital changes. The findings confirm the feasibility of redirecting near-Earth objects like asteroids as a planetary defense measure.

"We can't stop hurricanes or earthquakes yet, but we ultimately learned that we can prevent an asteroid impact with sufficient time, warning and resources," said Derek Richardson, a professor of astronomy at UMD and a DART investigation working group lead. "With sufficient time, a relatively small change in an asteroid's orbit would cause it to miss the Earth, preventing large-scale destruction from occurring on our planet."

DART mission more successful than expected

Richardson and his UMD Department of Astronomy colleagues Professor Jessica Sunshine and Principal Research Scientist Tony Farnham played critical roles in studying the effectiveness of the DART mission to deflect an asteroid from an Earth-bound path.

Farnham was instrumental in computing the geometrical conditions and dimensions needed to interpret observations of the event accurately. Using data from spacecraft engineers and from the Didymos Reconnaissance and Asteroid Camera for Optical Navigation (DRACO), Farnham helped determine what the DART spacecraft was looking at as it approached Dimorphos.

"When dealing with observations from a spacecraft, we need to understand where in space the spacecraft is located with respect to the asteroid, the sun and Earth and where it's facing at any given time," Farnham explained. "With this information, we have the context to make our conjectures and evaluate our work."

Thanks to Farnham's work, the DART team gained important information about the general timeline of the impact, the location and nature of the impact site, and the size and shape of Dimorphos. To the team's surprise, they found the small asteroid to be an oblate spheroid, or a slightly squashed sphere-like body, instead of a more elongated shape expected from theoretical predictions.

"Both Didymos and Dimorphos are more squishy in shape -- looking more like peanut butter M&Ms and less like peanut M&Ms -- than we expected," Sunshine said. "This shape also challenges some of our preconceptions about how such asteroids form and complicates the physics behind DART because it prompts us to rethink our current models of binary asteroids."

In addition to Dimorphos' irregular shape, the scientists also noticed that the asteroid's surface was noticeably bouldery and blocky. This geomorphic quality likely influenced crater formation, the amount and physical properties of ejecta (debris expelled from impacts), and the momentum of a DART-like impact.

Sunshine, who previously served as the deputy principal investigator for the UMD-led NASA Deep Impact mission, observed that these different textural qualities led to different impact outcomes -- critical in evaluating how successfully the DART spacecraft redirected Dimorphos from its original orbit.

"The Deep Impact mission collided with a comet whose surface is made up of small, mostly uniform grains," Sunshine explained. "Deep Impact resulted in a more uniform fan of debris than the filamentary structures seen after DART's impact into bouldery terrain. As it turns out, the movement of DART-caused ejecta really had a profound effect on the success of DART's mission."

Extra push from impact debris shortened Dimorphos' orbit

The DART spacecraft was not the sole provider of momentum in the impact with Dimorphos; an additional shove was caused by violent spews of debris when the spacecraft slammed into the diminutive asteroid moon.

"There was so much debris ejected from the impact that Dimorphos was pushed approximately 3.5 times more effectively compared to being hit by the DART spacecraft alone," explained Richardson, who helped compute and verify the momentum transferred between the DART spacecraft and Dimorphos.

According to Farnham, who calculated the direction of the asteroid's ejecta, this finding was confirmed when the team measured the asteroid's orbit had changed more than the team's more conservative expectations. The difference in orbital periods, or the length of time it takes for a celestial object to complete one rotation around another object, indicates that the orbit of Dimorphos around Didymos had changed.

"Pre-impact, we expected the impact to shorten Dimorphos' orbit by only about 10 minutes,'' Farnham said. "But after the impact, we learned that the orbital period was shortened even more, reducing an ordinarily 12-hour orbit by slightly more than 30 minutes. In other words, the ejected material acted as a jet to push the moon even further out of its original orbit."

Following up with Hera mission

The DART mission represents a major first step to developing appropriate planetary defense strategies against near-Earth objects like asteroids.

The DART team anticipates that the upcoming European Space Agency Hera mission launching in October 2024 will unravel more information about the DART impact site. By 2026-27, the Hera spacecraft will revisit the binary asteroid system containing Dimorphos and Didymos and assess the internal properties of both asteroids for the first time, providing a more detailed analysis of the DART impact's effects on the system and the geophysics behind solar system formation.

"We still don't know a lot about Dimorphos and Didymos because we have only seen the outsides," Sunshine said. "What is their internal structure like? Are there differences in porosity between the two? Those are the types of questions we need to answer to really see how effective our deflections are and how celestial bodies like those asteroids form and evolve."

While the Hera mission is still in the construction phase, research from both DART and its predecessors like Deep Impact still offer a wealth of information on how humans can develop additional ways to defend Earth from approaching asteroids and comets. Thanks to a legacy of kinetic impact testing initiatives and planetary defense research led by the late Distinguished University Professor of Astronomy Mike A'Hearn, UMD astronomers are uniquely equipped to evaluate and advance planetary scale impact experimentation. Richardson, Sunshine, Farnham and their colleagues hope to honor the work that led up to DART by continuing to help pioneer new methods of asteroid threat mitigation.

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Mulching time of forest meadows influences insect diversity

Mulching is a possible management method for forest meadows and is important to their upkeep. During the process, the meadow is cut and the cuttings are shredded and left on the meadow. Despite its significance, the effects of this method on insects living in this habitat has rarely been studied up to now. Dr. Maria M. Georgi of the team working with the head of the University of Freiburg's Chair of Nature Conservation and Landscape Ecology -- Prof. Dr. Alexandra-Maria Klein, and her colleagues studied this in-depth. The result: Nearly all the mulching times examined had a negative impact on insect larvae and flower-visiting insects which are found on forest meadows. Georgi says, "Management is important for the maintenance of forest meadows. That is why we're proposing alternative types of mulching be applied in future to improve conservation of the insects living there if no opportunity to apply another method, such as cut, is available."

Meadows are important to the forest; mulching is important to the meadows

Forest meadows are often managed to attract game animals. This reduces their browsing of young plants -- so the grazing of leaves and twigs -- in the surrounding woods. Management is required to retain forest meadows. Otherwise, the forest would spread increasingly and the meadow would disappear. Compared to other methods, mulching is more effective in terms of cost and labor intensity. During the processes the meadow is mowed and the cuttings are shredded and left on the meadow. Although the impact of cut on plant and insect diversity has been intensively investigated, the opposite had been the case for mulching up to now.

Examining of four mulching times

The study was carried out at 24 locations in the northern Black Forest. The focus was on insect larvae and insect flower-visitors. The researchers examined how different mulching times affected these insects. Six locations were designated for a control group. They were not mulched. These were compared with six meadows that were mulched either in June or September, as well as six additional meadows that were mulched both in June and September. In terms of insect larvae, sawflies (Symphyta) accounted for 45 percent of the population studied, with butterflies (Lepidoptera) making up 44 percent. Hover files (Syrphidae) dominated the flower-visiting insects. They made up a share of 80 percent.

September mulching protects flower-visiting insects

For the insect larvae, all three mulching times studied had a negative impact on numbers compared to the control group. The findings were similar for the flower-visiting insects. Here, mulching in June, as well as mulching in June and September, had a negative impact on the number of insects counted. Yet September mulching had no impact in the case of flower-visitors. Georgi concludes, "On the basis of our results, we can recommend mulching in September in order to protect flower-visitors."

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Oldest human genome from southern Spain

A new study reports on genomic data from a 23,000-year-old individual who lived in what was probably the warmest place of Europe at the peak of the last Ice Age. The oldest human genome recovered from the southern tip of Spain adds an important piece of the puzzle to the genetic history of Europe.

An international team of researchers has analysed ancient human DNA from several archaeological sites in Andalucía in southern Spain. Thestudy reports on the oldest genome to date from Cueva del Malalmuerzo in southern Spain, as well as the 7,000 to 5,000-year-old genomes of early farmers from other well-known sites, such as Cueva de Ardales.

The Iberian Peninsula plays an important role in the reconstruction of human population history. As a geographic cul-de-sac in the southwest of Europe, it is on one hand considered a refuge during the last Ice Age with its drastic temperature fluctuations. On the other hand, it may have been one of the starting points for the recolonisation of Europe after the glacial maximum. Indeed, previous studies had reported on the genomic profiles of 13,000 to 8,000-year-old hunter-gatherers from the Iberian Peninsula and provided evidence for the survival and continuation of a much older Palaeolithic lineage that has been replaced in other parts of Europe and is no longer detectable.

After an organism's death, its DNA is only preserved for a certain period of time and under favourable climatic conditions. Extracting DNA from ancient remains from hot and dry climates is a huge challenge for researchers. In Andalucía, in the south of present-day Spain, climatic conditions are similar to those in North Africa -- however, DNA has successfully been recovered of 14,000-year-old human individuals from a cave site in Morocco. The new study fills crucial temporal and spatial gaps. Researchers can now directly investigate the role of the southern Iberian Peninsula as a refuge for Ice Age populations and potential population contacts across the Strait of Gibraltar during the last Ice Age, when sea-levels were much lower than today.

In the right place at the right time

The genetic ancestry of individuals from central and southern Europe who lived before the Last Glacial Maximum (24,000 to 18,000 years before today) differs from the ones who recolonised Europe afterwards. However, the situation in western Europe has not been clear until now due to a lack of genomic data from critical time periods. The 23,000-year-old individual from Cueva del Malalmuerzo near Granada finally adds data from the time when large parts of Europe were covered by massive ice sheets. The study describes a direct genetic link between a 35,000-year-old individual from Belgium and the new genome from Malalmuerzo. "Thanks to the high quality of our data we were able to detect traces of one of the first genetic lineages that settled Eurasia 45,000 years ago. Importantly, we found similarities with a 35,000-year-old individual from Belgium whose ancestry we can now trace further to the 23,000-year-old individual from southern Iberia," explains first author Vanessa Villalba-Mouco of the Max Planck Institute for Evolutionary Anthropology.

The individual from Cueva del Malalmuerzo not only links to earlier periods of settlement but also to the hunter-gatherers of southern and western Europe who lived long after the last Ice Age. It also confirms the important role of the Iberian Peninsula as a refuge for human populations during the last Ice Age. From there, humans migrated northwards and eastwards once the ice sheets had retreated. "With Malalmuerzo, we managed to find the right place and the right time period to trace a Palaeolithic human group back to one of the proposed Ice Age refugia. It is remarkable to find such a long-lasting genetic legacy on the Iberian Peninsula, especially since this pre-Ice Age ancestry had long since disappeared in other parts of Europe," adds senior author Wolfgang Haak of the Max Planck Institute for Evolutionary Anthropology.

More puzzle pieces of human history

Interestingly, the authors did not find any genetic link between the southern Iberian Peninsula and North Africa -- despite a distance of only 13 kilometres across the Mediterranean Sea, and parallels in the archaeological record. "In Malalmuerzo, we found no evidence of a genetic contribution from North African lineages, and conversely, there is no evidence of a genetic contribution from southern Spain in the genomes of the 14,000-year-old individuals from the Taforalt cave in Morocco," adds Gerd-Christian Weniger from the University of Cologne. "Why the Strait of Gibraltar was a barrier at the end of the last Ice Age is still one of the unresolved questions of archaeological research in the western Mediterranean region."

The study also includes a number of younger individuals from the Neolithic, a time period when the first farmers arrived in Europe from the Near East. The characteristic genetic ancestry of Anatolian Neolithic groups is indeed detectable in the individuals from Andalucía, suggesting that these early farmers spread over large geographic distances. "Neolithic people from southern Iberia, however, show a higher proportion of hunter-gatherer lineages. Hence, interaction between the last hunters and the first farmers may have been much closer than in other regions," says co-author Jose Ramos-Muñoz from Universidad de Cádiz.

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Ice Age survivors

The team analysed the genomes of 356 prehistoric hunter gatherers from different archaeological cultures -- including new data sets of 116 individuals from 14 different European and Central Asian countries. Modern humans began to spread across Eurasia around 45,000 years ago but previous research showed that the first modern humans that arrived in Europe did not contribute to later populations. This study focuses on the people who lived between 35,000 and 5,000 years ago and that are, at least partially, the ancestors of the present-day population of Western Eurasia, including -- for the first time -- the genomes of people who lived during the Last Glacial Maximum (LGM), the coldest phase of the last Ice Age, around 25,000 years ago.

Climatic refugium or dead end?

Surprisingly, the research team found that populations from different regions associated with the Gravettian culture, which was widespread across the European continent between 32,000 and 24,000 years ago, were not closely related to each other. They were linked by a common archaeological culture: they used similar weapons and produced similar portable art. Genetically, however, the populations from western and southwestern Europe (today's France and Iberia) differed from contemporaneous populations from central and southern Europe (today's Czech Republic and Italy).

Furthermore, the gene pool of the western Gravettian populations is found continuously for at least 20,000 years: their descendants who are associated with the Solutrean and Magdalenian cultures stayed in southwestern Europe during the coldest period of the last Ice Age (between 25,000 and 19,000 years ago) and later spread north-eastward to the rest of Europe. "With these findings, we can for the first time directly support the hypothesis that during the Last Glacial Maximum people found refuge in the climatically more favourable region of southwestern Europe" says first author Cosimo Posth.

The Italian peninsula was previously considered to be another climatic refugium for humans during the LGM. However, the research team found no evidence for this, on the contrary: hunter-gatherer populations associated with the Gravettian culture and living in central and southern Europe are no longer genetically detectable after the LGM. People with a new gene pool settled in these areas, instead. "We find that individuals associated with a later culture, the Epigravettian, are genetically distinct from the area's previous inhabitants," says co-author He Yu. "Presumably, these people came from the Balkans, arrived first in northern Italy around the time of the glacial maximum and spread all the way south to Sicily."

Large-scale genetic replacement

The analysed genomes also show that the descendants of these Epigravettian inhabitants of the Italian peninsula spread across the rest of Europe about 14,000 years ago, replacing populations associated with the Magdalenian culture. The research team describes a large-scale genetic replacement that may have been caused, in part, by climatic changes that forced people to migrate: "At that time, the climate warmed up quickly and considerably and forests spread across the European continent. This may have prompted people from the south to expand their habitat. The previous inhabitants may have migrated to the north as their habitat, the 'mammoth' steppe, dwindled," says Johannes Krause, the study's senior author.

Furthermore, the findings show that there had been no genetic exchange between contemporaneous hunter-gatherer populations in western and eastern Europe for more than 6,000 years. Interactions between people from central and eastern Europe can only be detected again from 8,000 years ago. "At that time, hunter-gatherers with distinct ancestries and appearances started to mix with each other. They were different in many aspects, including their skin and eye colour," says He Yu.

During this time agriculture and a sedentary lifestyle spread from Anatolia to Europe. "It is possible that the migration of early farmers into Europe triggered the retreat of hunter-gatherer populations to the northern edge of Europe. At the same time, these two groups started mixing with each other, and continued to do so for around 3,000 years," Krause says.

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Baby star near the black hole in the middle of our Milky Way: It exists after all

An international team of researchers under the leadership of Dr Florian Peißker at the University of Cologne's Institute of Astrophysics has discovered a very young star in its formation phase near the supermassive black hole Sagittarius A* (Sgr A*) at the centre of our Milky Way. The star is only several tens of thousands of years old, making it younger than humanity. The special thing about baby star X3a is that theoretically it should not be able to exist so close to the supermassive black hole in the first place. However, the team believes that it formed in a dust cloud orbiting the giant black hole and sank to its current orbit only after it had formed. The study "X3: a high-mass Young Stellar Object close to the supermassive black hole Sgr A*" has been published in The Astrophysical Journal.

The vicinity of the black hole at the centre of our Galaxy is generally considered to be a region characterized by highly dynamic processes and hard X-ray and UV radiation. Precisely these conditions act against the formation of stars like our Sun. Therefore, for a long time scientists had assumed that over periods of billions of years, only old, evolved stars can settle by dynamical friction in the vicinity of the supermassive black hole. However, quite surprisingly, already twenty years ago very young stars were found in the immediate vicinity of Sgr A*. It is still not clear how these stars got there or where they formed. The occurrence of very young stars very close to the supermassive black hole has been referred to as "the paradox of youth."

The baby star X3a -- which is ten times as big and fifteen times as heavy as our Sun -- could now close the gap between star formation and the young stars in the immediate vicinity of Sgr A*. X3a needs special conditions to form in the immediate vicinity of the black hole. First author Dr Florian Peißker explained: "It turns out that there is a region at a distance of a few light years from the black hole which fulfils the conditions for star formation. This region, a ring of gas and dust, is sufficiently cold and shielded against destructive radiation." Low temperatures and high densities create an environment in which clouds of hundreds of solar masses can form. These clouds can in principle move very fast towards the direction of the black hole due to cloud-cloud collisions and scattering that remove the angular momentum.

In addition, very hot clumps formed in close proximity to the baby star which could then be accreted by X3a. These clumps could thus also contribute to X3a reaching such a high mass in the first place. However, these clumps are only a part of the formation history of X3a. They still do not explain its "birth."

The scientists assume the following scenario to be possible: shielded from the gravitational influence of Sgr A* and intense radiation, a dense enough cloud could have formed in the outer gas and dust ring around the centre of the Galaxy. This cloud had a mass of about one hundred suns and collapsed under its own gravity to one or more protostars. "This so-called fall time approximately corresponds to the age of X3a," Peißker added. Observations have shown that there are many of these clouds that can interact with each other. It is therefore likely that a cloud falls towards the black hole from time to time.

This scenario would also fit X3a's stellar development phase, which is currently evolving into a mature star. It is therefore quite plausible that the gas and dust ring acts as the birthplace of the young stars in the centre of our Galaxy. Dr Michal Zaja?ek at Masaryk University in Brno (Czech Republic), a co-author of the study, clarified: "With its high mass of about ten times the Solar mass, X3a is a giant among stars, and these giants evolve very quickly towards maturity. We have been lucky to spot the massive star in the midst of the comet-shaped circumstellar envelope. Subsequently, we identified key features associated with a young age, such as the compact circumstellar envelope rotating around it."

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Galactic explosion offers astrophysicists new insight into the cosmos

Using data from the James Webb Space Telescope's first year of interstellar observation, an international team of researchers was able to serendipitously view an exploding supernova in a faraway spiral galaxy.

The study, published recently in The Astrophysical Journal Letters, provides new infrared measurements of one of the brightest galaxies in our cosmic neighborhood, NGC 1566, also known as the Spanish Dancer. Located about 40 million light-years away from Earth, the galaxy's extremely active center has led it to become especially popular with scientists aiming to learn more about how star-forming nebulae form and evolve.

In this case, scientists were able to survey a Type 1a supernova -- the explosion of a carbon-oxygen white dwarf star, which Michael Tucker, a fellow at the Center for Cosmology and AstroParticle Physics at The Ohio State University and a co-author of the study, said researchers caught by mere chance while studying NGC 1566.

"White dwarf explosions are important to the field of cosmology, as astronomers often use them as indicators of distance," said Tucker. "They also produce a huge chunk of the iron group elements in the universe, such as iron, cobalt and nickel."

The research was made possible thanks to the PHANGS-JWST Survey, which, due to its vast inventory of star cluster measurements, was used to create a reference dataset to study in nearby galaxies. By analyzing images taken of the supernova's core, Tucker and co-author Ness Mayker Chen, a graduate student in astronomy at Ohio State who led the study, aimed to investigate how certain chemical elements are emitted into the surrounding cosmos after an explosion.

For instance, light elements like hydrogen and helium were formed during the big bang, but heavier elements can be created only through the thermonuclear reactions that happen inside supernovas. Understanding how these stellar reactions affect the distribution of iron elements around the cosmos could give researchers deeper insight into the chemical formation of the universe, said Tucker.

"As a supernova explodes, it expands, and as it does so, we can essentially see different layers of the ejecta, which allows us to probe the nebula's core," he said. Powered by a process called radioactive decay -- wherein an unstable atom releases energy to become more stable -- supernovas emit radioactive high-energy photons like uranium-238. In this instance, the study specifically focused on how the isotope cobalt-56 decays into iron-56.

Using data from JWST's near-infrared and mid-infrared camera instruments to investigate the evolution of these emissions, researchers found that more than 200 days after the initial event, supernova ejecta was still visible at infrared wavelengths that would have been impossible to image from the ground.

"This is one of those studies where if our results weren't what we expected, it would have been really concerning," he said. "We've always made the assumption that energy doesn't escape the ejecta, but until JWST, it was only a theory."

For many years, it was unclear whether fast-moving particles produced when cobalt-56 decays into iron-56 seeped into the surrounding environment, or were held back by the magnetic fields supernovas create.

Yet by providing new insight into the cooling properties of supernova ejecta, the study confirms that in most circumstances, ejecta doesn't escape the confines of the explosion. This reaffirms many of the assumptions scientists have made in the past about how these complex entities work, Tucker said.

"This study validates almost 20 years' worth of science," he said. "It doesn't answer every question, but it does a good job of at least showing that our assumptions haven't been catastrophically wrong."

Future JWST observations will continue to help scientists develop their theories about star formation and evolution, but Tucker said that further access to other types of imaging filters could help test them as well, creating more opportunities to understand wonders far beyond the edges of our own galaxy.

"The power of JWST is really unparalleled," said Tucker. "It's really promising that we're accomplishing this kind of science and with JWST, there's a good chance we'll not only be able to do the same for different kinds of supernovas, but do it even better."

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Ancient proteins offer new clues about origin of life on Earth

By simulating early Earth conditions in the lab, researchers have found that without specific amino acids, ancient proteins would not have known how to evolve into everything alive on the planet today -- including plants, animals, and humans.

The findings, which detail how amino acids shaped the genetic code of ancient microorganisms, shed light on the mystery of how life began on Earth.

"You see the same amino acids in every organism, from humans to bacteria to archaea, and that's because all things on Earth are connected through this tree of life that has an origin, an organism that was the ancestor to all living things," said Stephen Fried, a Johns Hopkins chemist who co-led the research with scientists at Charles University in the Czech Republic. "We're describing the events that shaped why that ancestor got the amino acids that it did."

The findings are newly published in the Journal of the American Chemical Society.

In the lab, the researchers mimicked primordial protein synthesis of 4 billion years ago by using an alternative set of amino acids that were highly abundant before life arose on Earth.

They found ancient organic compounds integrated the amino acids best suited for protein folding into their biochemistry. In other words, life thrived on Earth not just because some amino acids were available and easy to make in ancient habitats but because some of them were especially good at helping proteins adopt specific shapes to perform crucial functions.

"Protein folding was basically allowing us to do evolution before there was even life on our planet," Fried said. "You could have evolution before you had biology, you could have natural selection for the chemicals that are useful for life even before there was DNA."

Even though the primordial Earth had hundreds of amino acids, all living things use the same 20 of these compounds. Fried calls those compounds "canonical." But science has struggled to pinpoint what's so special -- if anything -- about those 20 amino acids.

In its first billion years, Earth's atmosphere consisted of an assortment of gases like ammonia and carbon dioxide that reacted with high levels of ultraviolet radiation to concoct some of the simpler canonical amino acids. Others arrived via special delivery by meteorites, which introduced a mixed bag of ingredients that helped life on Earth complete a set of 10 "early" amino acids.

How the rest came to be is an open question that Fried's team is trying to answer with the new research, especially because those space rocks brought much more than the "modern" amino acids.

"We're trying to find out what was so special about our canonical amino acids," Fried said. "Were they selected for any particular reason?"

Scientists estimate Earth is 4.6 billion years old, and that DNA, proteins, and other molecules didn't begin to form simple organisms until 3.8 billion years ago. The new research offers new clues into the mystery of what happened during the time in between.

"To have evolution in the Darwinian sense, you need to have this whole sophisticated way of turning genetic molecules like DNA and RNA into proteins. But replicating DNA also requires proteins, so we have a chicken-and-egg problem," Fried said. "Our research shows that nature could have selected for building blocks with useful properties before Darwinian evolution."

Scientists have spotted amino acids in asteroids far from Earth, suggesting those compounds are ubiquitous in other corners of the universe. That's why Fried thinks the new research could also have implications for the possibility of finding life beyond Earth.

"The universe seems to love amino acids," Fried said. "Maybe if we found life on a different planet, it wouldn't be that different."

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Dinosaur claws used for digging and display

Dinosaur claws had many functions, but now a team from the University of Bristol and the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing has shown some predatory dinosaurs used their claws for digging or even for display.

The study focused on two groups of theropod dinosaurs, the alvarezsaurs and therizinosaurs, that had weird claws whose function had been a mystery up to now. It turns out that alvarezsaurs used their rock-pick-like claws for digging, but their close relatives, the giant therizinosaurs, used their overdeveloped, metre-long, sickle-like claws for display.

The new work is led by Zichuan Qin, a PhD student at the University of Bristol and the IVPP. He developed a new, computational approach in biomechanics to identify functions based on detailed comparison with living animals. First, the claws were modelled in three dimensions from CT scans, then modelled for stress and strain using engineering methods, and finally matched to functions of pulling, piercing and digging by comparison with modern animals whose claw functions are known.

"Alvarezsaurs and therizinosaurs are definitely the strangest cousins among dinosaurs," said Professor Michael Benton, one of Zichuan's supervisors. "Alvarezsaurs were the tiniest dinosaurs ever, the size of chickens, with stubby forelimbs and robust single claws, but their closest relative, the therizinosaurs, evolved in the exact opposite path."

"Therizinosaurus is famous for its sickle-like claws, each as long as a samurai sword: Edward Scissor-hands on speed. We all saw Therizinosaurus in 'Jurassic World' hitting deer and killing the giant predator Giganotosaurus. However, this is unlikely. These long, narrow claws were too weak for combat." said Dr Chun-Chi Liao, an expert on therizinosaurs from IVPP who co-authored this study. "Our engineering simulation shows that these claws could not withstand much stress."

"Not all therizinosaur hand claws were so useless in combat, but most other related species could use their claws as powerful hooking tools when feeding on leaves from the trees.," Dr Chun-Chi Liao added, "so, we conclude that the largest claws of any animal ever were actually useless in mechanical function, and so must have evolved under sexual selection to be used in display. The adult Therizinosaurus I guess could wave the claws at a competitor and effectively say, 'look at me, back off' or wave them around in some way like a peacock can use its tail in display to attract females for mating."

"Our previous work has shown that alvarezsaurs evolved to become the tiniest dinosaurs by the end of the Cretaceous, and these [dinosaurs] were using their punchy little claws for digging into ant hills and termite mounds. They were ant-eaters," said Zichuan Qin.

"Our study shows that the early alvarezsaurs, like Haplocheirus from the Jurassic, had multifunctional hands, but they were not good at digging. Their much smaller descendants had the efficient digging hands so they could feast on the Late Cretaceous termites." added Zichuan Qin.

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Unusual atom helps in search for Universe's building blocks

An unusual form of caesium atom is helping a University of Queensland-led research team unmask unknown particles that make up the Universe.

Dr Jacinda Ginges, from UQ's School of Mathematics and Physics, said the unusual atom -- made up of an ordinary caesium atom and an elementary particle called a muon -- may prove essential in better understanding the Universe's fundamental building blocks.

"Our Universe is still such a mystery to us," Dr Ginges said.

"Astrophysical and cosmological observations have shown that the matter we know about -commonly referred to as 'Standard Model' particles in physics -- makes up only five percent of the matter and energy content of the Universe.

"Most matter is 'dark', and we currently know of no particle or interaction within the Standard Model that explains it.

"The search for dark matter particles lies at the forefront of particle physics research, and our work with caesium might prove essential in solving this mystery."

The work may also one day improve technology.

"Atomic physics plays a major role in technologies we use every day, such as navigation with the Global Positioning System (GPS), and atomic theory will continue to be important in the advancement of new quantum technologies based on atoms," Dr Ginges said.

Through theoretical research, Dr Ginges and her team have improved the understanding of the magnetic structure of caesium's nucleus, its effects in atomic caesium and the effects of the weird and wonderful muon.

"A muon is basically a heavy electron -- 200 times more massive -- and it orbits the nucleus 200 times closer than the electrons," Dr Ginges said.

"Because of this, it can pick up on details of the structure of the nucleus.

"It sounds complicated, but in a nutshell, this work will help to improve atomic theory calculations that are used in the search for new particles."

The researchers said the new approach can offer greater sensitivity and an alternative technique to finding new particles, through the use of precision atomic measurements.

"You may have heard of the Large Hadron Collider at CERN, the world's largest and most powerful particle accelerator, which smashes together subatomic matter at high energies to find previously unseen particles," Dr Ginges said.

"But our research can offer greater sensitivity, with an alternative technique to find new particles -- through precision atomic measurements.

"It doesn't need a giant collider, and instead uses precision instruments to look for atomic changes at low energy.

"Rather than explosive, high-energy collisions, it's the equivalent of creating an ultra-sensitive 'microscope' to witness the true nature of atoms.

"This can be a more sensitive technique, unveiling particles that particle colliders simply can't see."

Caesium is having a moment, after being featured in the news recently, as the element in the radioactive capsule that went missing, and was subsequently found, in Western Australia's outback.

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Deadly waves: Researchers document evolution of plague over hundreds of years in medieval Denmark

Scientists who study the origins and evolution of the plague have examined hundreds of ancient human teeth from Denmark, seeking to address longstanding questions about its arrival, persistence and spread within Scandinavia.

In the first longitudinal study of its kind, focusing on a single region for 800 years (between 1000-1800AD), researchers reconstructed Yersinia pestis genomes, the bacterium responsible for the plague, and showed that it was reintroduced into the Danish population from other parts of Europe again and again, perhaps via human movement, with devastating effects.

The historical samples were taken from nearly 300 individuals located at 13 different archaeological sites throughout the country.

"We know that plague outbreaks across Europe continued in waves for approximately 500 years, but very little about its spread throughout Denmark is documented in historical archives," says Ravneet Sidhu, one of the study's lead authors and a graduate student at McMaster's Ancient DNA Centre, where the analysis was conducted.

The McMaster researchers, working with a team of historians and bioarchaeologists in Denmark and Manitoba, performed an in-depth examination of the relatedness and differences between the different strains of plague that were present in Denmark during this time.

They reconstructed and sequenced the genomes of Y. pestis, using fragments teased from ancient teeth, which can preserve traces of blood-borne infection for centuries. They compared the plague genomes to one another and to their modern-day relatives.

Researchers found positive plague samples in 13 individuals who had lived and died over a period of three centuries.

Nine of those samples provided enough genetic information to draw evolutionary conclusions about the plague's persistence in Denmark. The results create a picture of urban and rural populations hammered by relentless waves of plague.

"The high frequency of Y. pestis reintroduction to Danish communities is consistent with the assumption that most deaths in the period were due to newly introduced pathogens. This association between pathogen introduction and mortality illuminates essential aspects of the demographic evolution, not only in Denmark but across the whole European continent," says Jesper L. Boldsen, the skeletal collection curator and paleodemographer at ADBOU, University of Southern Denmark.

The analysis, reported today in the journal Current Biology, revealed that the Danish Y. pestis sequences were interspersed with medieval and early modern strains from other European countries, including the Baltic region and Russia, rather than coming from a single domestic cluster that re-emerged from natural reservoirs over the centuries.

"The evidence for plague in Denmark, both historical and archaeological, has been far more sparse than in some other regions, such as England and Italy. This study identified plague for the first time from medieval Denmark, therefore enabling us to connect the experience in Denmark to disease patterns elsewhere," said Julia Gamble a co-author on the study and assistant professor of anthropology at the University of Manitoba.

In striking detail, researchers describe the earliest known appearance of Y. pestis in Denmark in the town of Ribe dating back to 1333 during the Black Death, its appearance in rural areas such Tirup -- where there is no surviving historical evidence -- and its disappearance by 1649.

Most places it hit in Denmark were port cities, but one of the last outbreaks struck a small rural site in the centre of the country with no access to water, suggesting importation via land.

Plague is a disease of rodents, but clearly the results suggest human-facilitated movement of plague, either via rodents travelling with humans or via other vectors, such as lice, on them.

"The results reveal new connections between past and present experiences of plague, and add to our understanding of the distribution, patterns and virulence of re-emerging diseases," says Hendrik Poinar, senior author of the paper, director of the McMaster Ancient DNA Centre and an investigator with the Michael G. DeGroote Institute for Infectious Disease Research.

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New method creates material that could create the next generation of solar cells

Perovskites, a family of materials with unique electric properties, show promise for use in a variety fields, including next-generation solar cells. A Penn State-led team of scientists created a new process to fabricate large perovskite devices that is more cost- and time-effective than previously possible and that they said may accelerate future materials discovery.

"This method we developed allows us to easily create very large bulk samples within several minutes, rather than days or weeks using traditional methods," said Luyao Zheng, a postdoctoral researcher in the Department of Materials Science at Penn State and lead author on the study. "And our materials are high quality -- their properties can compete with single-crystal perovskites."

The researchers used a sintering method called the electrical and mechanical field-assisted sintering technique (EM-FAST) to create the devices. Sintering is a commonly used process to compress fine powders into a solid mass of material using heat and pressure.

A typical process for making perovskites involves wet chemistry -- the materials are liquefied in a solvent solution and then solidified into thin films. These materials have excellent properties, but the approach is expensive and inefficient for creating large perovskites and the solvents used may be toxic, the scientists said.

"Our technique is the best of both worlds," said Bed Poudel, a researcher professor at Penn State and a co-author. "We get single-crystal-like properties, and we don't have to worry about size limitations or any contamination or yield of toxic materials."

Because it uses dry materials, the EM-FAST technique opens the door to include new dopants, ingredients added to tailor device properties, that are not compatible with the wet chemistry used to make thin films, potentially accelerating the discovery of new materials, the scientists said.

"This opens up possibilities to design and develop new classes of materials, including better thermoelectric and solar materials, as well as X- and γ-ray detectors," said Amin Nozariasbmarz, assistant research professor at Penn State and a co-author. "Some of the applications are things we already know, but because this is a new technique to make new halide perovskite materials with controlled properties, structures, and compositions, maybe there is room in the future for new breakthroughs to come from that."

In addition, the new process allows for layered materials -- one powder underneath another -- to create designer compositions. In the future, manufactures could design specific devices and then directly print them from dry powders, the scientists said.

"We anticipate this FAST perovskite would open another dimension for high throughput material synthesis, future manufacturing directly printing devices from powder and accelerating the material discovery of new perovskite compositions," said Kai Wang, an assistant research professor at Penn State and a co-author.

EM-FAST, also known as spark plasma sintering, involves applying electric current and pressure to powders to create new materials. The process has a 100% yield -- all the raw ingredients go into the final device, as opposed to 20 to 30% in solution-based processing.

The technique produced perovskite materials at .2 inch per minute, allowing scientists to create quickly create large devices that maintained high performance in laboratory tests. The team reported their findings in the journal Nature Communications.

Penn State scientists have long used EM-FAST to create thermoelectric devices. This work represents the first attempt to create perovskite materials with the technique, the scientists said.

"Because of the background we have, we were talking and thought we could change some parameters and try this with perovskites," Nozariasbmarz said. "And it just opened a door to a new world. This paper is a link to that door -- to new materials and new properties."

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Excess weight, obesity more deadly than previously believed

Excess weight or obesity boosts risk of death by anywhere from 22% to 91% -- significantly more than previously believed -- while the mortality risk of being slightly underweight has likely been overestimated, according to new CU Boulder research.

The findings, published Feb. 9 in the journal Population Studies, counter prevailing wisdom that excess weight boosts mortality risk only in extreme cases.

The statistical analysis of nearly 18,000 people also shines a light on the pitfalls of using body mass index (BMI) to study health outcomes, providing evidence that the go-to metric can potentially bias findings. After accounting for those biases, it estimates that about 1 in 6 U.S. deaths are related to excess weight or obesity.

"Existing studies have likely underestimated the mortality consequences of living in a country where cheap, unhealthy food has grown increasingly accessible, and sedentary lifestyles have become the norm," said author Ryan Masters, associate professor of sociology at CU Boulder.

"This study and others are beginning to expose the true toll of this public health crisis."

Challenging the obesity paradox

While numerous studies show that heart disease, high blood pressure and diabetes (which are often associated with being overweight) elevate mortality risk, very few have shown that groups with higher BMIs have higher mortality rates.

Instead, in what some call the "obesity paradox," most studies show a U-shaped curve: Those in the "overweight" category (BMI 25-30) surprisingly have the lowest mortality risk. Those in the "obese" category (30-35) have little or no increased risk over the so-called "healthy" category (18.5-25). And both the "underweight" (less than 18.5) and extremely obese (35 and higher) are at increased risk of death.

"The conventional wisdom is that elevated BMI generally does not raise mortality risk until you get to very high levels, and that there are actually some survival benefits to being overweight," said Masters, a social demographer who has spent his career studying mortality trends. "I have been suspicious of these claims."

He noted that BMI, which doctors and scientists often use as a health measure, is based on weight and height only and doesn't account for differences in body composition or how long a person has been overweight.

"It's a reflection of stature at a point in time. That's it," said Masters, noting that Tom Cruise (at 5 feet 7 inches and an extremely muscular 201 pounds at one point), had a BMI of 31.5, famously putting him in the category of "obese." "It isn't fully capturing all of the nuances and different sizes and shapes the body comes in."

To see what happened when those nuances were considered, Masters mined the National Health and Nutrition Examination Survey (NHANES) from 1988 to 2015, looking at data from 17,784 people, including 4,468 deaths.

He discovered that a full 20% of the sample characterized as "healthy" weight had been in the overweight or obese category in the decade prior. When set apart, this group had a substantially worse health profile than those in the category whose weight had been stable.

Masters pointed out that a lifetime carrying excess weight can lead to illnesses that, paradoxically, lead to rapid weight loss. If BMI data is captured during this time, it can skew study results.

"I would argue that we have been artificially inflating the mortality risk in the low-BMI category by including those who had been high BMI and had just lost weight recently," he said.

Meanwhile, 37% of those characterized as overweight and 60% of those with obese BMI had been at lower BMIs in the decade prior. Notably, those who had only recently gained weight had better health profiles.

"The health and mortality consequences of high BMI are not like a light switch," said Masters. "There's an expanding body of work suggesting that the consequences are duration-dependent."

By including people who had spent most of their life at low-BMI weight in the high-BMI categories, previous studies have inadvertently made high BMI look less risky than it is, he said.

When he looked at differences in fat distribution within BMI categories, he also found that variations made a huge difference in reported health outcomes.

Exposing a public health problem

Collectively, the findings confirm that studies have been "significantly affected" by BMI-related bias.

When re-crunching the numbers without these biases, he found not a U-shape but a straight upward line, with those with low BMI (18.5-22.5) having the lowest mortality risk.

Contrary to previous research, the study found no significant mortality risk increases for the "underweight" category.

While previous research estimated 2 to 3% of U.S. adult deaths were due to high BMI, his study pegs the toll at eight times that.

Masters said he hopes the research will alert scientists to be "extremely cautious" when making conclusions based on BMI. But he also hopes the work will draw attention to what he sees not as a problem for individuals alone to solve but rather a public health crisis fueled by an unhealthy or "obesogenic" environment in the U.S.

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A mysterious object is being dragged into the supermassive black hole at the Milky Way's center

For two decades, scientists have observed an elongated object named X7 near the supermassive black hole at the center of the Milky Way and wondered what it was. Was it pulled off a larger structure nearby? Was its unusual form the result of stellar winds or was it shaped by jets of particles from the black hole?

Now, having examined the evolution of X7 using 20 years of data gathered by the Galactic Center Orbit Inintiative, astronomers from the UCLA Galactic Center Group and the Keck Observatory propose that it could be a cloud of dust and gas that was ejected during the collision of two stars.

Over time, they report, X7 has stretched, and it is being pulled apart as the black hole drags it closer, exerting its tidal force upon the cloud. They expect that within the next few decades, X7 will disintegrate and the gas and dust of which it is composed will eventually be drawn toward the black hole, which is called Sagittarius A*, or Sgr A*.

The study is published in The Astrophysical Journal.

"No other object in this region has shown such an extreme evolution," said Anna Ciurlo, a UCLA assistant researcher and the paper's lead author. "It started off comet-shaped and people thought maybe it got that shape from stellar winds or jets of particles from the black hole. But as we followed it for 20 years we saw it becoming more elongated. Something must have put this cloud on its particular path with its particular orientation."

X7 has a mass of about 50 Earths and is on an orbital path around Sgr A* that would take 170 years to complete.

But that might never happen. Based on its trajectory, the team estimates that X7 will make its closest approach to Sgr A* around the year 2036, and then likely spiral toward Sgr A* and disappear.

"We anticipate the strong tidal forces exerted by the galactic black hole will ultimately tear X7 apart before it completes even one orbit," said co-author Mark Morris, UCLA professor of physics and astronomy.

Tidal forces are the gravitational pull that cause an object approaching a black hole to stretch; the side of the object closest to the black hole is pulled much more strongly than the opposite end.

X7 shows some of the same properties as the other strange dusty objects orbiting Sgr A*. Those so-called G objects look like gas but behave like stars. But X7's shape and velocity have changed more dramatically than G objects' have. As it accelerates toward the black hole, X7 is moving rapidly, clocking in at speeds of up to around 700 miles per second.

"It's exciting to see significant changes of X7's shape and dynamics in such great detail over a relatively short time scale as the gravitational forces of the supermassive black hole at the center of the Milky Way influences this object," Randy Campbell, a co-author of the paper and the science operations lead at the Keck Observatory, said in a statement.

Although X7's origin is still the subject of debate, the finding suggests that it arose after two stars collided.

"One possibility is that X7's gas and dust were ejected at the moment when two stars merged," Ciurlo said. "In this process, the merged star is hidden inside a shell of dust and gas, which might fit the description of the G objects. And the ejected gas perhaps produced X7-like objects."

The merger of two stars is very common, especially when they are near black holes, Ciurlo said.

"This is a very messy process: The stars circle each other, get closer, merge, and the new star is hidden within a cloud of dust and gas," she said. "X7 could be the dust and gas ejected from a merged star that's still out there somewhere."

The findings are the first estimate of X7's mildly elliptical orbit and the most robust analysis to date of the remarkable changes to its appearance, shape and behavior. The research team will continue to use the Keck Observatory to monitor X7's dramatic changes as the power of the black hole's gravity yanks it apart.

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New discovery sheds light on very early supermassive black holes

Astronomers from the University of Texas and the University of Arizona have discovered a rapidly growing black hole in one of the most extreme galaxies known in the very early Universe. The discovery of the galaxy and the black hole at its centre provides new clues on the formation of the very first supermassive black holes. The new work is published in Monthly Notices of the Royal Astronomical Society.

Using observations taken with the Atacama Large Millimeter Array (ALMA), a radio observatory sited in Chile, the team have determined that the galaxy, named COS-87259, containing this new supermassive black hole is very extreme, forming stars at a rate 1000 times that of our own Milky Way and containing over a billion solar masses worth of interstellar dust. The galaxy shines bright from both this intense burst of star formation and the growing supermassive black hole at its centre.

The black hole is considered to be a new type of primordial black hole -- one heavily enshrouded by cosmic "dust," causing nearly all of its light to be emitted in the mid-infrared range of the electromagnetic spectrum. The researchers have also found that this growing supermassive black hole (frequently referred to as an active galactic nucleus) is generating a strong jet of material moving at near light speed through the host galaxy.

Today, black holes with masses millions to billions of times greater than that of our own Sun sit at the centre of nearly every galaxy. How these supermassive black holes first formed remains a mystery for scientists, particularly because several of these objects have been found when the Universe was very young. Because the light from these sources takes so long to reach us, we see them as they existed in the past; in this case, just 750 million years after the Big Bang, which is approximately 5% of the current age of the Universe.

What is particularly astonishing about this new object is that it was identified over a relatively small patch of the sky typically used to detect similar objects -- less than 10 times the size of the full moon -- suggesting there could be thousands of similar sources in the very early Universe. This was completely unexpected from previous data.

The only other class of supermassive black holes we knew about in the very early Universe are quasars, which are active black holes that are relatively unobscured by cosmic dust. These quasars are extremely rare at distances similar to COS-87259, with only a few tens located over the full sky. The surprising discovery of COS-87259 and its black hole raises several questions about the abundance of very early supermassive black holes, as well as the types of galaxies in which they typically form.

Ryan Endsley, the lead author of the paper and now a Postdoctoral Fellow at The University of Texas at Austin, says "These results suggest that very early supermassive black holes were often heavily obscured by dust, perhaps as a consequence of the intense star formation activity in their host galaxies. This is something others have been predicting for a few years now, and it's really nice to see the first direct observational evidence supporting this scenario."

Similar types of objects have been found in the more local, present-day Universe, such as Arp 299 shown here. In this system, two galaxies are crashing together generating an intense starburst as well as heavy obscuration of the growing supermassive black hole in one of the two galaxies.

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