Astronomers discover new link between dark matter and clumpiness of the universe

In a study published today in the Journal of Cosmology and Astroparticle Physics, researchers at the University of Toronto reveal a theoretical breakthrough that may explain both the nature of invisible dark matter and the large-scale structure of the universe known as the cosmic web. The result establishes a new link between these two longstanding problems in astronomy, opening new possibilities for understanding the cosmos.

The research suggests that the "clumpiness problem," which centres on the unexpectedly even distribution of matter on large scales throughout the cosmos, may be a sign that dark matter is composed of hypothetical, ultra-light particles called axions. The implications of proving the existence of hard-to-detect axions extend beyond understanding dark matter and could address fundamental questions about the nature of the universe itself.

"If confirmed with future telescope observations and lab experiments, finding axion dark matter would be one of the most significant discoveries of this century," says lead author Keir Rogers, Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics in the Faculty of Arts & Science at the University of Toronto. "At the same time, our results suggest an explanation for why the universe is less clumpy than we thought, an observation that has become increasingly clear over the last decade or so, and currently leaves our theory of the universe uncertain."

Dark matter, comprising 85 percent of the universe's mass, is invisible because it does not interact with light. Scientists study its gravitational effects on visible matter to understand how it is distributed in the universe.

A leading theory proposes that dark matter is made of axions, described in quantum mechanics as "fuzzy" due to their wave-like behaviour. Unlike discrete point-like particles, axions can have wavelengths larger than entire galaxies. This fuzziness influences the formation and distribution of dark matter, potentially explaining why the universe is less clumpy than predicted in a universe without axions.

This lack of clumpiness has been observed in large galaxy surveys, challenging the other prevailing theory that dark matter consists only of heavy, weakly interacting sub-atomic particles called WIMPs. Despite experiments like the Large Hadron Collider, no evidence supporting the existence of WIMPs has been found.

"In science, it's when ideas break down that new discoveries are made and age-old problems are solved," says Rogers.

For the study, the research team -- led by Rogers and including members of associate professor Renée Hložek's research group at the Dunlap Institute, as well as from the University of Pennsylvania, Institute for Advanced Study, Columbia University and King's College London -- analyzed observations of relic light from the Big Bang, known as the Cosmic Microwave Background (CMB), obtained from the Planck 2018, Atacama Cosmology Telescope and South Pole Telescope surveys. The researchers compared these CMB data with galaxy clustering data from the Baryon Oscillation Spectroscopic Survey (BOSS), which maps the positions of approximately a million galaxies in the nearby universe. By studying the distribution of galaxies, which mirrors the behavior of dark matter under gravitational forces, they measured fluctuations in the amount of matter throughout the universe and confirmed its reduced clumpiness compared to predictions.

The researchers then conducted computer simulations to predict the appearance of relic light and the distribution of galaxies in a universe with long dark matter waves. These calculations aligned with CMB data from the Big Bang and galaxy clustering data, supporting the notion that fuzzy axions could account for the clumpiness problem.

Future research will involve large-scale surveys to map millions of galaxies and provide precise measurements of clumpiness, including observations over the next decade with the Rubin Observatory. The researchers hope to compare their theory to direct observations of dark matter through gravitational lensing, an effect where dark matter clumpiness is measured by how much it bends the light from distant galaxies, akin to a giant magnifying glass. They also plan to investigate how galaxies expel gas into space and how this affects the dark matter distribution to further confirm their results.

Understanding the nature of dark matter is one of the most pressing fundamental questions and key to understanding the origin and future of the universe.

Presently, scientists do not have a single theory that simultaneously explains gravity and quantum mechanics -- a theory of everything. The most popular theory of everything over the last few decades is string theory, which posits another level below the quantum level, where everything is made of string-like excitations of energy. According to Rogers, detecting a fuzzy axion particle could be a hint that the string theory of everything is correct.

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Preserving forests to protect deep soil from warming

A recent study led by scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of Zurich has revealed that the organic compounds proposed for carbon sequestration in deep soil are highly vulnerable to decomposition under global warming.

The finding has implications for a key strategy in carbon management that relies on soil and forests -- natural carbon "sinks" -- to mitigate global warming.

About 25 percent of global carbon emissions are captured by forests, grasslands, and rangelands. During photosynthesis, plants store carbon in their cell walls and in the soil. Because of rich carbon stores from decades past, soils contain twice as much carbon as the atmosphere does, and deeper subsoils (more than 8 inches or 20 centimeters) account for roughly half of the soil carbon. But as global populations rise, so do our demands for new croplands and timber. Research shows that disturbing the natural world for commerce has a price: the United Nations' Intergovernmental Panel on Climate Change has warned that emissions from deforestation and agriculture account for around a fifth of global greenhouse gases.

"Our study shows that climate change will affect all aspects of soil carbon and nutrient cycling. It also shows that in terms of carbon sequestration, there's no silver bullet. If we want soil to sustain carbon sequestration in a warming world, we will need better soil management practices, which can mean minimal disturbance of soils during forest management and agriculture," said Margaret Torn, a senior scientist in Berkeley Lab's Earth & Environmental Sciences Area and a senior author of the study.

In 2021, Torn and her research team provided the first physical evidence that warmer temperatures lead to a significant drop in the carbon stocks stored in deep forest soils -- a loss of 33% over five years.

In the new study, Torn and first author Cyrill Zosso of the University of Zurich unveil a clearer picture of soil in a warming world. This time, the research team is the first to show that warmer temperatures lead to a significant drop in the soil organic carbon compounds that are created by plants during photosynthesis.

During an experiment at the University of California's Blodgett Forest Research Station in the foothills of California's Sierra Nevada mountains, the researchers used vertical heating rods to continuously warm 1-meter-deep (three-foot-deep) plots of soil by 4 degrees Celsius (7 degrees Fahrenheit). That is the amount of warming projected by the end of the 21st century if greenhouse gas emissions remain high.

They found that just 4.5 years of warming at this temperature led to large changes in carbon stocks at a depth of more than 30 centimeters (or approximately 12 inches) below the soil surface.

During spectroscopic experiments at the University of Zurich, Zosso identified the organic compounds that were affected by the warming.

The results were shocking: a 17% loss in lignin -- the compounds that give plants rigidity -- and a nearly 30% loss in cutin and suberin, the waxy compounds in leaves, stems, and roots that protect plants from pathogens.

Torn and Zosso were also surprised to find a significant difference in the amount of "pyrogenic carbon" in the soil samples that were artificially heated versus the ones that were not. Pyrogenic carbon is a type of soil organic carbon derived from charred vegetation and other organic matter remnants left in the wake of a wildfire.

Many researchers assume that pyrogenic carbon has the most potential to serve as a very stable form of sequestered carbon. "We found much less pyrogenic carbon in the deep soils when they were heated," Torn said.

"Pyrogenic carbon can stay in the soil for decades or even centuries, but we need to understand its vulnerability to warming or to changes in land management. Our study suggests that this material decomposed just as fast as anything else would when the soil was warmed," Torn explained. "This shows that when you put material deep into soil where it's in contact with minerals and microbes, those natural systems will decompose the material over time."

The researchers next plan to resample soil from the study to determine how nine years of warming impact soil composition and health. A new grassland warming experiment at the Point Reyes National Seashore in Northern California is also on the horizon. "We are also organizing all the world's deep-soil warming (or whole-soil warming) experiments to share data and know-how and conducting synthesis of the data to see what we can learn," Torn said.

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Illusions are in the eye, not the mind

Numerous visual illusions are caused by limits in the way our eyes and visual neurones work -- rather than more complex psychological processes, new research shows.

Researchers examined illusions in which an object's surroundings affect the way we see its colour or pattern.

Scientists and philosophers have long debated whether these illusions are caused by neural processing in the eye and low-level visual centres in the brain, or involve higher-level mental processes such as context and prior knowledge.

In the new study Dr Jolyon Troscianko, from the University of Exeter, co-developed a model that suggests simple limits to neural responses -- not deeper psychological processes -- explain these illusions.

"Our eyes send messages to the brain by making neurones fire faster or slower," said Dr Troscianko, from the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"However, there's a limit to how quickly they can fire, and previous research hasn't considered how the limit might affect the ways we see colour."

The model combines this "limited bandwidth" with information on how humans perceive patterns at different scales, together with an assumption that our vision performs best when we are looking at natural scenes.

The model was developed by researchers from the Universities of Exeter and Sussex to predict how animals see colour, but it was also found to correctly predict many visual illusions seen by humans.

"This throws into the air a lot of long-held assumptions about how visual illusions work," Dr Troscianko said.

He said the findings also shed light on the popularity of high-definition televisions.

"Modern high dynamic range televisions create bright white regions that are over 10,000 times brighter than their darkest black, approaching the contrast levels of natural scenes," Dr Troscianko added.

"How our eyes and brains can handle this contrast is a puzzle because tests show that the highest contrasts we humans can see at a single spatial scale is around 200:1.

"Even more confusingly, the neurones connecting our eyes to our brains can only handle contrasts of about 10:1.

"Our model shows how neurones with such limited contrast bandwidth can combine their signals to allow us to see these enormous contrasts, but the information is 'compressed' -- resulting in visual illusions.

"The model shows how our neurones are precisely evolved to use of every bit of capacity.

"For example, some neurones are sensitive to very tiny differences in grey levels at medium-sized scales, but are easily overwhelmed by high contrasts.

"Meanwhile, neurones coding for contrasts at larger or smaller scales are much less sensitive, but can work over a much wider range of contrasts, giving deep black-and-white differences.

"Ultimately this shows how a system with a severely limited neural bandwidth and sensitivity can perceive contrasts larger than 10,000:1."

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Flaring star could be down to young planet's disc inferno

The mystery of a stellar flare a trillion times more powerful than the largest of Solar flares may have been solved by a team of scientists who believe a massive young planet is burning up in a superheated soup of raw material swirling around it.

Led by the University of Leicester and funded by the UK Science and Technology Facilities Council (STFC), the scientists have suggested that a planet roughly ten times larger in size than Jupiter is undergoing 'extreme evaporation' near to the growing star, with the inferno tearing material off the planet and flinging it onto the star.

They have published their findings in the journal Monthly Notices of the Royal Astronomical Society. Statistics of such flares in developing solar systems suggests that each could witness up to a dozen of similar planet elimination events.

The scientists focused their attention on the protostar FU Ori, located 1,200 light years from our solar system, which significantly increased in brightness 85 years ago and has still not dimmed to the usually expected luminosity.

While astronomers believe that the increase in FU Ori luminosity is due to more material falling onto the protostar from a cloud of gas and dust called a protoplanetary disc, details of that remained a mystery.

Lead author Professor Sergei Nayakshin from the University of Leicester School of Physics and Astronomy said: "These discs feed growing stars with more material but also nurture planets. Previous observations provided tantalizing hints of a young massive planet orbiting this star very close. Several ideas were put forward on how the planet may have encouraged such a flare, but the details did not work out. We discovered a new process which you might call a 'disc inferno' of young planets."

The Leicester-led researchers created a simulation for FU Ori, modelling a gas giant planet formed far out in the disc by gravitational instability in which a massive disc fragments to make huge clumps more massive than our Jupiter but far less dense.

The simulation shows how such a planetary seed migrates inward towards its host star very rapidly, drawn by its gravitational pull. As it reaches the equivalent of a tenth of the distance between Earth and our own sun, the material around the star is so hot it effectively ignites the outer layers of the planet's atmosphere. The planet then becomes a massive source of fresh material feeding the star and causing it to grow and shine brighter.

Study co-author Dr Vardan Elbakyan, also Leicester-based, adds: "This was the first star that that was observed to undergo this kind of flare. We now have a couple dozen examples of such flares from other young stars forming in our corner of the Galaxy. While FU Ori events are extreme compared to normal young stars, from the duration and observability of such events, observers concluded that most emerging solar systems flare up like this a dozen or so times while the protoplanetary disc is around."

Professor Nayakshin adds: "If our model is correct, then it may have profound implications for our understanding of both star and planet formation. Protoplanetary discs are often called nurseries of planets. But we now find that these nurseries are not quiet places that early solar system researchers imagined them to be, they are instead tremendously violent and chaotic places where many -- perhaps even most -- young planets get burned and literally eaten by their stars.

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A new Tatooine-like multi-planetary system identified

An international team of astronomers has announced the second-ever discovery of a multiplanetary circumbinary system.

Circumbinary systems contain planets that orbit around two stars in the centre instead of just one, like in our Solar System. Circumbinary planets orbit around both stars at once. The discovery, led by researchers at the University of Birmingham, is reported in today's issue of the journal Nature Astronomy.

The newly discovered planet is called BEBOP-1c, after the name of the project that collected the data. BEBOP stands for Binaries Escorted By Orbiting Planets. The BEBOP-1 system is also known as TOI-1338.

In 2020, a circumbinary planet, called TOI-1338b, was discovered in the same system using data from NASA's TESS space telescope, to which the Birmingham team also contributed. That planet was discovered with the transit method and was noticed because it passed in front of the brighter of the two stars on several occasions.

"The transit method permitted us to measure the size of TOI-1338b, but not its mass which is the planet's most fundamental parameter," said lead author Dr Matthew Standing, who completed his PhD at the University of Birmingham and is now a researcher at The Open University.

The BEBOP team was already monitoring this system using another detection method at the time, called the Doppler method. This method, also called the wobble method, or radial-velocity method, relies on accurately measuring the velocity of stars.

"This is the same method that led to the first exoplanet detection, for which Mayor and Queloz received the Nobel Prize in 2019." said Matthew's then supervisor, Amaury Triaud, a professor at the University of Birmingham.

Using state-of-the-art instruments installed on two telescopes located in the Atacama Desert in Chile, the team attempted to measure the mass of the planet noticed by TESS. Despite their best efforts, and years of work, the team could not achieve that, but instead they discovered a second planet, BEBOP-1c and measured its mass.

"Only 12 circumbinary systems are known so far, and this is only the second that hosts more than one planet," said David Martin, an astronomer and Sagan Fellow at the Ohio State University.

"BEBOP-1c has an orbital period of 215 days, and a mass 65 times larger than Earth, which is about five times less than Jupiter's mass," continues Dr Standing. "This was a difficult system to confirm, and our observations were interrupted by the COVID pandemic when telescopes in Chile closed for six months during a critical part of the planet's orbit. This part of the orbit only became observable again last year, when we finalised the detection."

At the moment only two planets are known in the TOI-1338/BEBOP-1 circumbinary system but more might be identified in the future, with similar observations as performed by the team.

Although rare, circumbinary planets are important in pushing the understanding of what happens when a planet is created.

"Planets are born in a disc of matter surrounding a young star, where mass progressively gathers into planets," explains Dr Lalitha Sairam, a researcher at the University of Birmingham and second author of the study.

"In the case of circumbinary geometries, the disc surrounds both stars. As both stars orbit one another, they act like a giant paddle that disturbs the disc close to them and prevents planet formation except for in regions that are quiet and far away from the binary. It is easier to pinpoint the location and conditions of planet formation in circumbinary systems compared to single stars like the Sun."

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Skipping evolution: Some kangaroos didn't hop

Extinct kangaroos used alternative methods to their famous hop according to comprehensive analysis from University of Bristol and the University of Uppsala scientists.

Although hopping is regarded as a pinnacle of kangaroo evolution, the researchers highlight that other kinds of large kangaroos, in the not too distant past, likely moved in different ways such as striding on two legs or traversing on all fours.

In the review, published in Alcheringa: An Australasian Journal of Palaeontology, the team shows that there are other ways to be an evolutionary successful large kangaroo and that large-bodied kangaroo weren't only specialised in endurance-hopping.

The review is an extensive discussion of the fossil evidence of the locomotion of kangaroos and their relatives (including wallabies, tree-kangaroos, rat-kangaroos, etc.) over the last 25 million years, and presents new analyses of limb bone and ankle bone metric data that add weight to previous locomotor hypotheses.

Together they indicated that the higher speed-endurance hopping, typical of modern large-bodied kangaroos, was probably rare or absent in all but a few large-bodied lineages, including the direct ancestors of modern large kangaroos like red and grey kangaroos. However, the diversity of kangaroo gaits disappeared with the Late Pleistocene extinctions of larger animals (in Australia as well as on other continents).

While almost all kangaroos today, small and large, use hopping gaits to some extent, the fossil record reveals that the locomotory capabilities of some extinct kangaroos were comparatively diverse.

The earliest recognized late Oligocene-middle Miocene (25to 15 million years ago) basal types of kangaroos most likely employed quadrupedal bounding, climbing and slower speed hopping as their primary modes of locomotion. (All kangaroos today use quadrupedal locomotion at slow speeds, which manifests as pentapedal locomotion -- using the tail as a fifth limb -- in larger species.) Yet, all these early forms were small-bodied, below 12kg, with larger bodied kangaroos over 20kg not appearing until the late Miocene (around 10 million years ago), coinciding with increasing aridity and the spread of openly vegetated habitats.

Hopping is functionally problematic at larger body sizes. Consequently, some members of the later kangaroo radiation achieved a more specialized anatomy for efficient higher-speed hopping at body sizes over 35kg. Modern large kangaroos are spectacular hoppers but none today are over 100kg (most individuals under 70 kg) and many extinct forms were well above this size and physically too big to hop.

Lead author Professor Christine Janis from Bristol's School of Earth Sciences said: "We want people to appreciate that large kangaroos were much more diverse as recently as 50 thousand years ago, which may also mean that the habitat in Australia then was rather different from today.

"In fact, modern large hopping kangaroos are the exception in kangaroo evolution."

While hopping apparently originated early in kangaroo evolution, in small-bodied forms, with the emergence of larger-sized kangaroos in the late Miocene there were several different options: to become more specialized for large-bodied endurance hopping, as in the ancestors of modern kangaroos, or to adopt other forms of locomotion at higher speeds, as in two main extinct lineages. The protemnodons (so-called 'giant wallabies', closely related to modern large kangaroos) likely relied upon a more quadrupedal type of locomotion most of the time, and rarely hopped. The sthenurine short-faced kangaroos, a lineage that split from all modern kangaroos around 15 million years ago, apparently adopted bipedal striding at all speeds.

The new data presented on the length of the tibia (shin bone) and calcaneum (ankle bone) reinforce these earlier hypotheses of locomotor differences from modern kangaroos in these two extinct groups. Co-author Adrian O'Driscoll, a former Master's student in the Palaeobiology program at Bristol and now a PhD student at the University of York made this contribution. He explained: "Especially supported by this new data is the notion of bipedal striding rather than hopping in the sthenurines, as their calcanea lack the anatomy (a long calcaneal heel) that would help resist rotational forces at the ankle experienced during hopping, and suggests a more-erect limb posture rather than the crouched posture essential for hopping."

Professor Janis concluded: "The assumption that increasing continent-wide aridity after the end of the Miocene selectively favoured hopping kangaroos is overly simplistic. Hopping is only one of many gait modes employed by kangaroos both in the past and today, and the fast endurance hopping of modern kangaroos should not be regarded as some "evolutionary pinnacle'.

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The Viking disease can be due to gene variants inherited from Neanderthals

Many men in northern Europe over the age of 60 suffer from the so-called Viking disease, which means that the fingers lock in a bent position. Now researchers at Karolinska Institutet, together with colleagues, have used data from over 7,000 affected individuals to look for genetic risk factors for the disease. The findings, which have been published in Molecular Biology and Evolution, show that three of the strongest risk factors are inherited from Neanderthals.

Up to 30 percent of men in northern Europe over 60 suffer from a condition called Dupuytren's contracture. The condition is sometimes called the Viking disease because it mainly affects individuals with northern European ancestry. The disease is significantly more common in men than women and usually begins as a lump in the palm of the hand that grows and causes one or more fingers to lock in a bent position. The condition is usually not painful, but the nodules may sometimes be tender to pressure.

The researchers in the study, led by Hugo Zeberg from Karolinska Institutet and Svante Pääbo from Max Planck Institute for Evolutionary Anthropology, set out to investigate whether genetic variants inherited from Neanderthals are involved in the disease.

Neanderthals lived in Europe and western Asia until about 40,000 years ago, when they were replaced by modern humans. However before Neanderthals disappeared, they mixed with modern humans. As a result, between one and two percent of the genomes of people with roots outside of Africa come from Neanderthals.

"Since Dupuytren's contracture is rarely seen in individuals of African descent, we wondered whether gene variants from Neanderthals can partly explain why people outside of Africa are affected," says Hugo Zeberg, assistant professor at the department of Physiology and Pharmacology, Karolinska Institutet.

The researchers used data from three large clinical cohorts in the US, UK, and Finland, which allowed them to compare the genomes of 7,871 sufferers and 645,880 healthy controls. They identified 61 genetic risk factors for Dupuytren's contracture. The researchers found that three of these were inherited from Neanderthals, and these included the second and third most important risk factors.

The study is further evidence that the intermingling between Neanderthals and our ancestors has important consequences for the prevalence of some diseases, particularly among certain groups.

"This is a case where the meeting with Neanderthals has affected who suffers from illness, although we should not exaggerate the connection between Neanderthals and Vikings," says Hugo Zeberg.

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DESI early data release holds nearly two million objects

The universe is big, and it's getting bigger. To study dark energy, the mysterious force behind the accelerating expansion of our universe, scientists are using the Dark Energy Spectroscopic Instrument (DESI) to map more than 40 million galaxies, quasars, and stars. Today, the collaboration publicly released its first batch of data, with nearly 2 million objects for researchers to explore.

The 80-terabyte data set comes from 2,480 exposures taken over six months during the experiment's "survey validation" phase in 2020 and 2021. In this period between turning the instrument on and beginning the official science run, researchers made sure their plan for using the telescope would meet their science goals -- for example, by checking how long it took to observe galaxies of different brightness, and by validating the selection of stars and galaxies to observe.

"The fact that DESI works so well, and that the amount of science-grade data it took during survey validation is comparable to previous completed sky surveys, is a monumental achievement," said Nathalie Palanque-Delabrouille, co-spokesperson for DESI and a scientist at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), which manages the experiment. "This milestone shows that DESI is a unique spectroscopic factory whose data will not only allow the study of dark energy but will also be coveted by the whole scientific community to address other topics, such as dark matter, gravitational lensing, and galactic morphology."

Today the collaboration also published a set of papers related to the early data release, which include early measurements of galaxy clustering, studies of rare objects, and descriptions of the instrument and survey operations. The new papers build on DESI's first measurement of the cosmological distance scale that was published in April, which used the first two months of routine survey data (not included in the early data release) and also showed DESI's ability to accomplish its design goals.

DESI uses 5,000 robotic positioners to move optical fibers that capture light from objects millions or billions of light-years away. It is the most powerful multi-object survey spectrograph in the world, able to measure light from more than 100,000 galaxies in one night. That light tells researchers how far away an object is, building a 3D cosmic map.

"Survey validation was very important for DESI because it allowed us -- before starting the main survey -- to adjust our selection of all the objects, including stars, bright galaxies, luminous red galaxies, emission line galaxies, and quasars," said Christophe Yeche, a scientist with the French Alternative Energies and Atomic Energy Commission (CEA) who co-leads the target selection group. "We've been able to optimize our selection and confirm our observation strategy."

As the universe expands, it stretches light's wavelength, making it redder -- a characteristic known as redshift. The further away the galaxy, the bigger the redshift. DESI specializes in collecting redshifts that can then be used to solve some of astrophysics' biggest puzzles: what dark energy is and how it has changed throughout the universe's history.

While DESI's primary goal is understanding dark energy, much of the data can also be used in other astronomical studies. For example, the early data release contains detailed images from some well-known areas of the sky, such as the Hubble Deep Field.

"There are some well-trodden spots where we've drilled down into the sky," said Stephen Bailey, a scientist at Berkeley Lab who leads data management for DESI. "We've taken valuable spectroscopic images in areas that are of interest to the rest of the community, and we're hoping that other people will take this data and do additional science with it."

Two interesting finds have already surfaced: Evidence of a mass migration of stars into the Andromeda galaxy, and incredibly distant quasars, the extremely bright and active supermassive black holes sometimes found at the center of galaxies.

"We observed some areas at very high depth. People have looked at that data and discovered very high redshift quasars, which are still so rare that basically any discovery of them is useful," said Anthony Kremin, a postdoctoral researcher at Berkeley Lab who led the data processing for the early data release. "Those high-redshift quasars are usually found with very large telescopes, so the fact that DESI -- a smaller, 4-meter survey instrument -- could compete with those larger, dedicated observatories was an achievement we are pretty proud of and demonstrates the exceptional throughput of the instrument."

Survey validation was also a chance to test the process of transforming raw data from DESI's ten spectrometers (which split a galaxy's light into different colors) into useful information.

"If you looked at them, the images coming directly from the camera would look like nonsense -- like lines on a weird, fuzzy image," said Laurie Stephey, a data architect at the National Energy Research Scientific Computing Center (NERSC), the supercomputer that processes DESI's data. "The magic happens in the processing and the software being able to decode the data. It's exciting that we have the technology to make that data accessible to the research community and that we can support this big question of 'what is dark energy?'"

DESI's early data was a unique project for NERSC. All of the experiment's code, including the computational heavy lifting, is written in the programming language Python rather than the traditional C++ or Fortran.

"That was the first time that using pure Python was shown to be a feasible approach for a major experiment at NERSC, and since then, Python has become increasingly common in our user workload," Stephey said.

The DESI early data release is now available to access for free through NERSC.

There is plenty of data yet to come from the experiment. DESI is currently two years into its five-year run and ahead of schedule on its quest to collect more than 40 million redshifts. The survey has already catalogued more than 26 million astronomical objects in its science run, and is adding more than a million per month.

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Hotter sand from microplastics could affect sea turtle development

New research from Florida State University published in Frontiers in Marine Science found that extreme concentrations of microplastics could increase the temperature of beach sand enough to threaten the development of incubating sea turtles.

Sea turtles play a vital role in the marine ecosystem, and for these oceangoing reptiles to thrive, they need healthy beaches where their eggs can incubate successfully.

"Sea turtle sex, fitness and hatchling success is influenced by temperature," said lead author Mariana Fuentes, an associate professor in FSU's Department of Earth, Ocean and Atmospheric Science. "Not much is known on how the presence of microplastic affects the thermal profile of sand. Understanding how changes to the environment could affect the temperature of nesting grounds is important for monitoring the future of these keystone species."

Researchers mixed sand from beaches at the FSU Coastal and Marine Laboratory with black and white microplastic. Concentrations of microplastic ranged from 5% to 30% of the total volume of the sediment sample. Then they recorded temperatures from July through September 2018 by burying digital thermometers at the same depth at which loggerhead sea turtles typically lay their eggs.

They found that samples with higher microplastic concentrations had greater increases in temperature, with the sample containing 30% black microplastic pieces having the highest mean difference in temperature. Those samples were 0.58 degrees Celsius warmer than the control group, an increase that could potentially significantly alter sea turtle hatchling sex ratios, physiological performance, and mortality of embryos.

The good news from the study is that the 30% concentration of microplastics in those samples equates to about 9.8 million pieces per cubic meter, a higher concentration than has been currently found on beaches worldwide. Current research has found the highest reported concentrations collected from beaches is about 1.8 million pieces per cubic meter.

But the amount of microplastics at nesting sites has only recently been explored. It could be higher in locations that haven't been studied yet, and demand for plastic is forecast to increase in the future.

At nesting grounds where incubating eggs are near a 29-degree Celsius boundary -- below which most hatchlings are male, and above which most hatchlings are female -- smaller concentrations of plastic could be enough to push the temperature beyond a crucial threshold.

"Sea turtle eggs are sensitive to temperature, and microplastics are another factor adding to the heat they face," Fuentes said. "This study gives us a baseline for future research on how they are affecting the nesting environment."

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Study explains unusual deformation in Earth's largest continental rift

Computer models confirm that the African Superplume is responsible for the unusual deformations as well as rift-parallel seismic anisotropy observed beneath the East African Rift System.

In continental rifting, there's a mix of stretching and breaking that reaches deep into the Earth, said geophysicist D. Sarah Stamps. Continental rifting involves the stretching of the lithosphere -- the outermost, rigid layer of the Earth. As the lithosphere stretches thin, its shallow regions experience brittle deformation, with the breaking of rock and earthquakes.

Stamps, who studies these processes by using computer modeling and GPS to map surface motions with millimeter precision, compares a rifting continent's different deformation styles with playing with Silly Putty.

"If you hit Silly Putty with a hammer, it can actually crack and break," said Stamps, associate professor in the Department of Geosciences, part of the Virginia Tech College of Science. "But if you slowly pull it apart, the Silly Putty stretches. So on different time scales, Earth's lithosphere behaves in different ways."

Whether in stretching or breaking, the deformation that comes with continental rifting usually follows predictable directional patterns in relation to the rift: The deformation tends to be perpendicular to the rift. The East African Rift System, the Earth's largest continental rift system, has those rift-perpendicular deformations. But after measuring the rift system with GPS instruments for more than 12 years, Stamps also observed deformation that went in the opposite direction, parallel to the system's rifts. Her team at the Geodesy and Tectonophysics Labhas worked to find out why.

In a recent study published in theJournal of Geophysical Research, the team explored the processes behind the East African Rift System using 3D thermomechanical modeling developed by the study's first author, Tahiry Rajaonarison, a postdoctoral researcher at New Mexico Tech who earned his Ph.D. at Virginia Tech as a member of Stamps's lab. His models showed that the rift system's unusual, rift-parallel deformation is driven by northward mantle flow associated with the African Superplume, a massive upwelling of mantle that rises from deep within the Earth beneath southwest Africa and goes northeast across the continent, becoming more shallow as it extends northward.

Their findings, combined with insights from a study the researchers published in 2021 using Rajaonarison's modeling techniques, could help clear up scientific debate on which plate-driving forces dominate the East African Rift System, accounting for both its rift-perpendicular and rift-parallel deformation: lithospheric buoyancy forces, mantle traction forces, or both.

As a postdoctoral researcher, Stamps began observing the East African Rift System's unusual, rift-parallel deformation using data from GPS stations that measured signals from more than 30 satellites orbiting Earth, from about 25,000 kilometers away. Her observations have added a layer of complexity to the debate around what drives the rift system.

Some scientists see the rifting in East Africa as driven primarily by lithospheric buoyancy forces, which are relatively shallow forces attributed mainly to the rift system's high topography, known as the African Superswell, and to density variations in the lithosphere. Others point to horizontal mantle traction forces, the deeper forces arising from interactions with mantle flowing horizontally beneath East Africa, as the primary driver.

The team's 2021 study found through 3D computational simulations that the rift and its deformation could be driven by a combination of the two forces. Their models showed that lithospheric buoyancy forces were responsible for the more predictable, rift-perpendicular deformation, but those forces couldn't account for the anomalous, rift-parallel deformation picked up by Stamps's GPS measurements.

In their newly published study, Rajaonarison again used 3D thermomechanical modeling, this time to focus on the source of the rift-parallel deformations. His models confirm that the African Superplume is responsible for the unusual deformations as well as rift-parallel seismic anisotropy observed beneath the East African Rift System.

Seismic anisotropy is the orientation or alignment of rocks in a particular direction in response to mantle flow, melt pockets, or pre-existing structural fabrics in the lithosphere, Stamps said. In this case, the rocks' alignment followed the direction of the African Superplume's northward mantle flow, which suggests mantle flow as their source.

"We are saying that the mantle flow is not driving the east-west, rift-perpendicular direction of some of the deformations, but that it may be causing the anomalous northward deformation parallel to the rift," Rajaonarison said. "We confirmed previous ideas that lithospheric buoyancy forces are driving the rift, but we're bringing new insight that anomalous deformation can happen in East Africa."

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Pass the salt: This space rock holds clues as to how Earth got its water

Sodium chloride, better known as table salt, isn't exactly the type of mineral that captures the imagination of scientists. However, a smattering of tiny salt crystals discovered in a sample from an asteroid has researchers at the University of Arizona Lunar and Planetary Laboratory excited, because these crystals can only have formed in the presence of liquid water.

Even more intriguing, according to the research team, is the fact that the sample comes from an S-type asteroid, a category known to mostly lack hydrated, or water-bearing, minerals. The discovery strongly suggests that a large population of asteroids hurtling through the solar system may not be as dry as previously thought. The finding, published in Nature Astronomy, gives renewed push to the hypothesis that most, if not all, water on Earth may have arrived by way of asteroids during the planet's tumultuous infancy.

Tom Zega, the study's senior author and a professor of planetary sciences at the UArizona Lunar and Planetary Laboratory, and Shaofan Che, lead study author and a postdoctoral fellow at the Lunar and Planetary Laboratory, performed a detailed analysis of samples collected from asteroid Itokawa in 2005 by the Japanese Hayabusa mission and brought to Earth in 2010.

The study is the first to demonstrate that the salt crystals originated on the asteroid's parent body, ruling out any possibility they might have formed as a consequence of contamination after the sample reached Earth, a question that had plagued previous studies that found sodium chloride in meteorites of a similar origin.

"The grains look exactly like what you would see if you took table salt at home and placed it under an electron microscope," Zega said. "They're these nice, square crystals. It was funny, too, because we had many spirited group meeting conversations about them, because it was just so unreal."

Zega said the samples represent a type of extraterrestrial rock known as an ordinary chondrite. Derived from so-called S-type asteroids such as Itokawa, this type makes up about 87% of meteorites collected on Earth. Very few of them have been found to contain water-bearing minerals.

"It has long been thought that ordinary chondrites are an unlikely source of water on Earth," said Zega who is the director of the Lunar and Planetary Laboratory's Kuiper Materials Imaging & Characterization Facility. "Our discovery of sodium chloride tells us this asteroid population could harbor much more water than we thought."

Today, scientists largely agree that Earth, along with other rocky planets such as Venus and Mars, formed in the inner region of the roiling, swirling cloud of gas and dust around the young sun, known as the solar nebula, where temperatures were very high -- too high for water vapor to condense from the gas, according to Che.

"In other words, the water here on Earth had to be delivered from the outer reaches of the solar nebula, where temperatures were much colder and allowed water to exist, most likely in the form of ice," Che said. "The most likely scenario is that comets or another type of asteroid known as C-type asteroids, which resided farther out in the solar nebula, migrated inward and delivered their watery cargo by impacting the young Earth."

The discovery that water could have been present in ordinary chondrites, and therefore been sourced from much closer to the sun than their "wetter" kin, has implications for any scenario attempting to explain the delivery of water to the early Earth.

The sample used in the study is a tiny dust particle spanning about 150 micrometers, or roughly twice the diameter of a human hair, from which the team cut a small section about 5 microns wide -- just large enough to cover a single yeast cell -- for the analysis.

Using a variety of techniques, Che was able to rule out that the sodium chloride was the result of contamination from sources such as human sweat, the sample preparation process or exposure to laboratory moisture.

Because the sample had been stored for five years, the team took before and after photos and compared them. The photos showed that the distribution of sodium chloride grains inside the sample had not changed, ruling out the possibility that any of the grains were deposited into the sample during that time. In addition, Che performed a control experiment by treating a set of terrestrial rock samples the same as the Itokawa sample and examining them with an electron microscope.

"The terrestrial samples did not contain any sodium chloride, so that convinced us the salt in our sample is native to the asteroid Itokawa," he said. "We ruled out every possible source of contamination."

Zega said tons of extraterrestrial matter is raining down on Earth every day, but most of it burns up in the atmosphere and never makes it to the surface.

"You need a large enough rock to survive entry and deliver that water," he said.

Previous work led by the late Michael Drake, a former director of the Lunar and Planetary Lab, in the 1990s proposed a mechanism by which water molecules in the early solar system could become trapped in asteroid minerals and even survive an impact on Earth.

"Those studies suggest several oceans worth of water could be delivered just by this mechanism," Zega said. "If it now turns out that the most common asteroids may be much 'wetter' than we thought, that will make the water delivery hypothesis by asteroids even more plausible."

Itokawa is a peanut-shaped near-Earth asteroid about 2,000 feet long and 750 feet in diameter and is believed to have broken off from a much larger parent body. According to Che and Zega, it is conceivable that frozen water and frozen hydrogen chloride could have accumulated there, and that naturally occurring decay of radioactive elements and frequent bombardment by meteorites during the solar system's early days could have provided enough heat to sustain hydrothermal processes involving liquid water. Ultimately, the parent body would have succumbed to the pummeling and broken up into smaller fragments, leading to the formation of Itokawa.

"Once these ingredients come together to form asteroids, there is a potential for liquid water to form," Zega said. "And once you have liquids form, you can think of them as occupying cavities in the asteroid, and potentially do water chemistry."

The evidence pointing at the salt crystals in the Itokawa sample as being there since the beginning of the solar system does not end here, however. The researchers found a vein of plagioclase, a sodium-rich silicate mineral, running through the sample, enriched with sodium chloride.

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Astronomers discover supernova explosion through rare 'cosmic magnifying glasses'

According to Einstein's general theory of relativity, time and space are fused together in a quantity known as spacetime. The theory suggests that massive objects, like a galaxy or galaxy clusters, can cause spacetime to curve. Gravitational lensing is a rare yet observable example of Einstein's theory in action; the mass of a large celestial body can significantly bend light as it travels through spacetime, much like a magnifying lens. When light from a more distant light source passes by this lens, scientists can use the resulting visual distortions to view objects that would otherwise be too far away and too faint to be seen.

An international team of scientists, including University of Maryland astronomer Igor Andreoni, recently discovered an exceptionally rare gravitationally lensed supernova, which the team named "SN Zwicky." Located more than 4 billion light years away, the supernova was magnified nearly 25 times by a foreground galaxy acting as a lens. The discovery presents a unique opportunity for astronomers to learn more about the inner cores of galaxies, dark matter and the mechanics behind universe expansion. The researchers published their findings -- including a comprehensive analysis, spectroscopic data and imaging of SN Zwicky -- in the journal Nature Astronomy on June 12, 2023.

"The discovery of SN Zwicky not only showcases the remarkable capabilities of modern astronomical instruments but also represents a significant step forward in our quest to understand the fundamental forces shaping our universe," said the paper's lead author Ariel Goobar, who is also the director of the Oskar Klein Center at Stockholm University.

Initially detected at the Zwicky Transient Facility (ZTF), SN Zwicky was quickly flagged as an object of interest due to its unusual brightness. Then, using adaptive optics instruments on the W.M. Keck Observatory, the Very Large Telescopes and NASA's Hubble Space Telescope, the team observed four images of SN Zwicky taken from different positions in the sky and confirmed that gravitational lensing was behind the supernova's extraordinary radiance.

According to Andreoni, who is a postdoctoral associate in UMD's Department of Astronomy and NASA's Goddard Space Flight Center, supernovae like SN Zwicky play a crucial role in helping scientists measure cosmic distances.

"SN Zwicky not only is magnified by the gravitational lense, but it also belongs to a class of supernovae that we call 'standard candles' because we can use their well-known luminosities to determine distance in space," Andreoni explained. "When a source of light is farther away, the light is dimmer -- just like seeing candles in a dark room. We can compare two light sources in this way and gain an independent measure of distance without having to actually study the galaxy itself."

In addition to being useful as a metric for cosmic distance, SN Zwicky also opens new avenues of research for scientists exploring the properties of galaxies, including dark matter (which is matter that does not absorb, reflect or emit light but make up the majority of matter in the universe). Researchers also believe that lensed supernovae like SN Zwicky could prove to be very promising tools for examining dark energy (a mysterious force counteracting gravity and drives the accelerated expansion of the universe) and refining current models describing the universe's expansion, including the calculation of the Hubble constant -- a value that describes how fast the universe is expanding.

For Andreoni, who is preparing for the opening of the Vera Rubin Observatory in Chile, the team's success in identifying and analyzing SN Zwicky is only the beginning. Now still in its construction phase, the new observatory is expected to begin full operations in 2024 and build upon the team's findings as it takes multiple images of the entire visible sky to search for other supernovae and asteroids. Andreoni believes that the "big picture" tactic used to find SN Zwicky will continue to help scientists gather large volumes of data about celestial events in the sky.

Read more at Science Daily

Geologists challenge conventional view of Earth's continental history, stability with new study

The seemingly stable regions of the Earth's continental plates -- the so-called stable cratons -- have suffered repetitive deformation below their crust since their formation in the remote past, according to new research from the University of Illinois Urbana-Champaign. This hypothesis defies decades of conventional plate tectonics theory and begs to answer why most cratons have remained structurally stable while their underbellies have experienced significant change.

In a study led by Illinois geology professor Lijun Liu, researchers used previously collected density data from the Earth's uppermost rigid layers of crust and mantle -- known as the lithosphere -- to examine the relationship between craton surface topography and the thickness of their underlying lithosphere layer.

The results of the study are published in the journal Nature Geosciences.

The lack of deformation within the cratons since their formation makes them the longest-lived tectonic units on Earth -- surviving supercontinent cycles like the formation and breakup of the supercontinent Pangea, as well as the lesser-known and more ancient supercontinent Rodina, the study reports.

"It is generally accepted that the cratons are protected by their thick underlying mantle roots, or keels, which are believed to be buoyant and strong and thus stable over time," Lui said.

Several recent papers from Liu's research group directly challenge this wisdom by showing that these mantle keels are actually quite dense.

In a 2022 study, the team demonstrated that the traditional view of buoyant craton keels implies that most of the Earth's cratons would be sitting about 3 kilometers above the sea surface, while in reality, their elevation is only a few 100 meters. This requires the lithospheric mantle below the crust to be of high enough density to pull the surface down by about 2 kilometers, Liu said.

In another study, the team used gravity field measurements to pinpoint the density structure of the craton keels to find that the lower portion of the mantle keel is most likely where the high-density material resides, implying a depth-increasing density profile below the cratons.

In the new paper, the team shows that the lower portion of the mantle keel that has a high density and tends to repeatedly peel away from the lithosphere above when mantle upwellings, called plumes, initiate supercontinent breakup. The peeled-off -- or delaminated -- keels could return to the base of the lithosphere after they warm up inside the hot mantle.

"The whole process is like what happens in a lava lamp, where the cool material near the surface sinks and the warm material near the bottom rises," Liu said.

This deformation history is expressed in some of the more puzzling geophysical properties observed in the lithosphere, the study reports.

"For example, the repetitive vertical deformation of the lower half of the mantle keel allows the seismic waves that vibrate the rock vertically to travel faster, compared to the upper half of the keel, which experienced less vertical deformation," Liu said.

The team also determined that mantle delamination will cause the craton surface to rise, leading to erosion.

"This is reflected in the strong dependence of crustal thickness on lithospheric thickness, an observation never made before this study," Liu said. "In particular, there are two major uplift and erosion events in the past, when supercontinents Rodinia and Pangea each separated, the former causing what is known as the Great Unconformity -- a feature in the Earth's rock record shows no evidence of new deposition, only deep craton erosion. This is the reason why we see pieces of ancient lower crust exposed at the craton's surface today."

With the help of numerical simulations, the team said that this episodic deformation style of the lower craton keels is how the craton crusts survived the long geological history.

"We believe this newly hypothesized lifestyle of cratons will significantly change people's view on how continents evolve and how plate tectonics operate on Earth," Liu said.

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Researchers uncover why light-to-moderate drinking is tied to better heart health

A new study led by investigators from Massachusetts General Hospital, a founding member of the Mass General Brigham healthcare system, offers an explanation for why light-to-moderate alcohol consumption may be associated with lower risk of heart disease. For the first time, researchers found that alcohol, in light to moderate quantities, was associated with long-term reductions in stress signaling in the brain. This impact on the brain's stress systems appeared to significantly account for the reductions in cardiovascular events seen in light to moderate drinkers participating in the study. Findings are published in the Journal of the American College of Cardiology.

"We are not advocating the use of alcohol to reduce the risk of heart attacks or strokes because of other concerning effects of alcohol on health," says senior author and cardiologist Ahmed Tawakol, MD, co-director of the Cardiovascular Imaging Research Center at Massachusetts General Hospital. "We wanted to understand how light to moderate drinking reduces cardiovascular disease, as demonstrated by multiple other studies. And if we could find the mechanism, the goal would be to find other approaches that could replicate or induce alcohol's protective cardiac effects without the adverse impacts of alcohol."

Previous epidemiological studies have suggested that light to moderate alcohol consumption (1 drink per day for women and 1 to 2 drinks per day for men) is associated with a lower risk of cardiovascular disease. But it was unknown whether alcohol was inducing cardiovascular benefits, or whether light/moderate drinkers' health behaviors, socioeconomic status, or other factors protected their hearts.

The study, led by K Mezue and M Osborne, included more than 50,000 individuals enrolled in the Mass General Brigham Biobank. The first part of the study evaluated the relationship between light/moderate alcohol consumption and major adverse cardiovascular events after adjusting for a range of genetic, clinical, lifestyle, and socioeconomic confounders. The researchers found that light/moderate alcohol consumption was associated with a substantial reduction in the risk of cardiovascular disease events, even after accounting for those other factors.

Next, they studied a subset of 754 individuals who had undergone previous PET/CT brain imaging (primarily for cancer surveillance) to determine the effect of light/moderate alcohol consumption on resting stress-related neural network activity.

The brain imaging showed reduced stress signaling in the amygdala, the brain region associated with stress responses, in individuals who were light to moderate drinkers compared to those who abstained from alcohol or who drank little. And when the investigators looked at these individuals' history of cardiovascular events, they found fewer heart attacks and strokes in light to moderate drinkers. "We found that the brain changes in light to moderate drinkers explained a significant portion of the protective cardiac effects," says Tawakol.

It's long been known that alcohol reduces the amygdala's reactivity to threatening stimuli while individuals are drinking. The current study is the first to indicate that light to moderate alcohol consumption has longer-term neurobiological effects in dampening activity in the amygdala, which may have a significant downstream impact on the cardiovascular system.

"When the amygdala is too alert and vigilant, the sympathetic nervous system is heightened, which drives up blood pressure and increases heart rate, and triggers the release of inflammatory cells," explains Tawakol. "If the stress is chronic, the result is hypertension, increased inflammation, and a substantial risk of obesity, diabetes, and cardiovascular disease."

Finally, the investigators examined whether light/moderate alcohol would be even more effective at reducing heart attacks and strokes in people who are prone to a chronically higher stress response, such as those with a history of significant anxiety. They found that, within the 50,000-patient sample, light to moderate drinking was associated with nearly double the cardiac-protective effect in individuals with a history of anxiety compared with others.

Yet while light/moderate drinkers lowered their risk for cardiovascular disease, the study also showed that any amount of alcohol increases the risk of cancer. And at higher amounts of alcohol consumption -- more than 14 drinks a week -- heart attack risk started to increase while overall brain activity started to decrease (which may be associated with adverse cognitive health).

The authors concluded that research should focus on finding new interventions that reduce the brain's stress activity without the deleterious effects of alcohol. The research team is currently studying the effect of exercise, stress-reduction interventions such as meditation, and pharmacological therapies on stress-associated neural networks and how they might induce cardiovascular benefits.

Read more at Science Daily

Which came first: The reptile or the egg?

The earliest reptiles, birds and mammals may have borne live young, researchers from Nanjing University and University of Bristol have revealed.

Until now, the hard-shelled egg was thought to be the key to the success of the amniotes -- a group of vertebrates that undergo embryonic or fetal development within an amnion, a protective membrane inside the egg.

However, a fresh study of 51 fossil species and 29 living species which could be categorised as oviparous (laying hard or soft-shelled eggs) or viviparous (giving birth to live young) suggests otherwise.

The findings, published today in Nature Ecology & Evolution, show that all the great evolutionary branches of Amniota, namely Mammalia, Lepidosauria (lizards and relatives), and Archosauria (dinosaurs, crocodilians, birds) reveal viviparity and extended embryo retention in their ancestors.

Extended embryo retention (EER) is when the young are retained by the mother for a varying amount of time, likely depending on when conditions are best for survival.

While the hard-shelled egg has often been seen as one of the greatest innovations in evolution, this research implies it was EER that gave this particular group of animals the ultimate protection.

Professor Michael Benton from the Bristol's School of Earth Sciences explained: "Before the amniotes, the first tetrapods to evolve limbs from fishy fins were broadly amphibious in habits. They had to live in or near water to feed and breed, as in modern amphibians such as frogs and salamanders.

"When the amniotes came on the scene 320 million years ago, they were able to break away from the water by evolving waterproof skin and other ways to control water loss. But the amniotic egg was the key. It was said to be a 'private pond' in which the developing reptile was protected from drying out in the warm climates and enabled the Amniota to move away from the waterside and dominate terrestrial ecosystems."

Project Leader Professor Baoyu Jiang added: "This standard view has been challenged. Biologists had noticed many lizards and snakes display flexible reproductive strategy across oviparity and viviparity.

"Sometimes, closely related species show both behaviours, and it turns out that live-bearing lizards can flip back to laying eggs much more easily than had been assumed."

"Also, when we look at fossils, we find that many of them were live-bearers, including the Mesozoic marine reptiles like ichthyosaurs and plesiosaurs," said Dr Armin Elsler. "Other fossils, including a choristodere from the Cretaceous of China, described here, show the to-and-fro between oviparity and viviparity happened in other groups, not just in lizards."

Dr Joseph Keating explained: "EER is widespread among vertebrates today, where the developing young are retained by the mother for a lesser or greater span of time.

"EER is common and variable in lizards and snakes today. Their young can be released, either inside an egg or as little wrigglers, at different developmental stages, and there appears to be ecological advantages of EER, perhaps allowing the mothers to release their young when temperatures are warm enough and food supplies are rich."

Professor Benton concluded: "Our work, and that of many others in recent years, has consigned the classic 'reptile egg' model of the textbooks to the wastebasket.

"The first amniotes had evolved extended embryo retention rather than a hard-shelled egg to protect the developing embryo for a lesser or greater amount of time inside the mother, so birth could be delayed until environments become favourable.

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What made the brightest cosmic explosion of all time so exceptional?

Few cosmic explosions have attracted as much attention from space scientists as the one recorded on October 22 last year and aptly named the Brightest of All Time (BOAT). The event, produced by the collapse of a highly massive star and the subsequent birth of a black hole, was witnessed as an immensely bright flash of gamma rays followed by a slow-fading afterglow of light across frequencies.

Since picking up the BOAT signal simultaneously on their giant telescopes, astrophysicists the world over have been scrambling to account for the brightness of the gamma-ray burst (GRB) and the curiously slow fade of its afterglow.

Now an international team that includes Dr Hendrik Van Eerten from the Department of Physics at the University of Bath in the UK has formulated an explanation: the initial burst (known as GRB 221009A) was angled directly at Earth and it also dragged along an unusually large amount of stellar material in its wake.

The team's findings are published today in the journal Science Advances. Dr Brendan O'Connor, a newly graduated doctoral student at the University of Maryland and George Washington University in Washington, DC is the study's lead author.

Dr Van Eerten, who co-led the theoretical analysis of the afterglow, said: "Other researchers working on this puzzle have also come to the conclusion that the jet was pointed directly at us -- much like a garden hose angled to spray straight at you -- and this definitely goes some way to explain why it was seen so brightly.

But what remained a puzzle was that the edges of the jet could not be seen at all.

"The slow fade of the afterglow is not characteristic of a narrow jet of gas, and knowing this made us suspect there was an additional reason for the intensity of the explosion, and our mathematical models have borne this out.

"Our work clearly shows that the GRB had a unique structure, with observations gradually revealing a narrow jet embedded within a wider gas outflow where an isolated jet would normally be expected."

So what made this GRB wider than normal? The researchers have a theory. As Dr Van Eerten explained: "GRB jets need to go through the collapsing star in which they are formed, and what we think made the difference in this case was the amount of mixing that happened between the stellar material and the jet, such that shock-heated gas kept appearing in our line of sight all the way up to the point that any characteristic jet signature would have been lost in the overall emission from the afterglow."

He added: "Our model helps not just to understand the BOAT, but also previous brightness record holders that had astronomers mystified about their lack of jet signature. These GRBs, like other GRBs, must be directed straight towards us when they happen, as it would be unphysical for that much energy to be expelled in all directions at once.

"An exceptional class of events appears to exist that are both extreme and manage to mask the directed nature of their gas flow. Future study into the magnetic fields that launch the jet and into the massive stars that host them should help reveal why these GRBs are so rare."

Read more at Science Daily

South Africa, India and Australia shared similar volcanic activity 3.5 billion years ago

Cratons are pieces of ancient continents that formed several billions of years ago. Their study provides a window as to how processes within and on the surface of Earth operated in the past. Cratons preserve relics of our young Earth as they host a variety of rock assemblages such as greenstones and granites. Greenstones are rock assemblages that primarily comprise of sub-marine volcanic rocks with minor sedimentary rocks. They are the best archives to study early Earth surface processes. A new study published in Precambrian Research by a team of researchers, led by Dr Jaganmoy Jodder of the University of the Witwatersrand's Evolutionary Studies Institute shows that the Singhbhum Craton in India hosts remarkably well preserved volcanic and sedimentary rocks as old as 3.5 billion years, and that it has similar geologic history to parts of South Africa and Australia.

The team that included researchers from the University of the Witwatersrand (Wits University), University of Johannesburg (UJ) and Chinese Academy of Sciences, Beijing, examined volcanic and sedimentary rocks from the Daitari greenstone belt in the Singhbhum Craton of India that were formed approximately 3.5 billion years ago. Jodder and his co-workers conducted detailed field-based studies and precise Uranium-Lead (U-Pb) radiometric-age dating to evaluate the geology of the ancient greenstone rocks. Based on their study, the researchers established key geological timelines that illustrate the tectonic evolution of the Daitari greenstones.

"The Daitari greenstone belt shares a similar geologic make-up when compared to the greenstones exposed in the Barberton and Nondweni areas of South Africa and those from the Pilbara Craton of north-western Australia," says Jodder.

Sub-marine volcanic eruptions were common between 3.5 and 3.3 billion-years-ago, which are largely preserved as pillowed lava within the greenstones of the Singhbhum, Kaapvaal and Pilbara cratons. More importantly the style of volcanism decoded from the silicic rocks provide evidence for explosive sub-marine to sub-aerial settings.

"Following silicic volcanism, sedimentary rocks that comprise sub-marine turbidity current deposits formed upon drowning of the volcanic vent. This provided us with an age estimate for the sub-marine sedimentary rocks that got deposited approximately 3.5 billion years ago, which was based on precise detrital U-Pb zircon data."

Studies of ancient greenstones are important not only to understand the diverse volcanic processes but well-preserved greenstones preserve minor sedimentary rocks that formed under sub-marine settings.

"These volcano-sedimentary rocks provide clues related to habitable environments on the young Earth and can be regarded as time capsules to help us better understand the evolutionary tale of the planet in its early stages," says Jodder.

Jodder and the team of researchers propose that these ancient continents may have been subjected to geologically similar processes 3.5 billion years ago.

"However, we are not certain about their palaeo-geographic positioning. And thus, cannot validate that they once formed part of a supercontinent," says Jodder.

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Ancient herbivore's diet weakened teeth leading to eventual starvation, study suggests

A team of researchers from the University of Bristol have shed light on the life of the ancient reptile Rhynchosaur, which walked the earth between 250-225 million years ago, before being replaced by the dinosaurs.

Rhynchosaurs are a little-understood group of roughly sheep-sized ancient reptiles that thrived during the Triassic Period, a time of generally warm climates and tough vegetation.

In the new study, the researchers studied specimens found in Devon and used CT scanning to see how the teeth wore down as they fed, and how new teeth were added at the backs of the tooth rows as the animals grew in size.

The findings, published today in Palaeontology, show that these early herbivores likely eventually starved to death in old age, the vegetation taking its toll on their teeth.

"I first studied the rhynchosaurs years ago," said team-leader Professor Mike Benton from Bristol's School of Earth Sciences, "and I was amazed to find that in many cases they dominated their ecosystems. If you found one fossil, you found hundreds. They were the sheep or antelopes of their day, and yet they had specialized dental systems that were apparently adapted for dealing with masses of tough plant food."

Dr Rob Coram, who discovered the Devon fossils, said: "The fossils are rare, but occasionally individuals were entombed during river floods. This has made it possible to put together a series of jaw bones of rhynchosaurs that ranged in age from quite young, maybe even babies, through adults, and including one particularly old animal, a Triassic old-timer whose teeth had worn right down and probably struggled to get enough nutrition each day."

"Comparing the sequence of fossils through their lifetime, we could see that as the animals aged, the area of the jaws under wear at any time moved backwards relative to the front of the skull, bringing new teeth and new bone into wear," said Thitiwoot Sethapanichsakul who studied the jaws as part of his MSc in Palaeobiology. "They were clearly eating really tough food such as ferns, that wore the teeth down to the bone of the jaw, meaning that they were basically chopping their meals by a mix of teeth and bone."

"Eventually, though, after a certain age -- we're not sure quite how many years -- their growth slowed down and the area of wear was fixed and just got deeper and deeper," added Dr Coram. "It's like elephants today -- they have a fixed number of teeth that come into use from the back, and after the age of seventy or so they're on their last tooth, and then that's that.

"We don't think the rhynchosaurs lived that long, but their plant food was so testing that their jaws simply wore out and presumably they eventually starved to death."

The rhynchosaurs were an important part of the ecosystems on land during the Triassic, when life was recovering from the world's greatest mass extinction, at the end of the preceding Permian Period. These animals were part of this recovery and setting the scene for new types of ecologies when first dinosaurs, and later mammals became dominant, as the modern world was being slowly constructed.

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The first prehistoric wind instruments discovered in the Levant

Although the prehistoric site of Eynan-Mallaha in northern Israel has been thoroughly examined since 1955, it still holds some surprises for scientists. Seven prehistoric wind instruments known as flutes, recently identified by a Franco-Israeli team, are the subject of an article published on 9 June in Nature Scientific Reports.

The discovery of these 12,000 -year-old aerophones is extremely rare -- in fact, they are the first to be discovered in the Near East. The "flutes," made from the bones of a small waterfowl, produce a sound similar to certain birds of prey (Eurasian sparrowhawk and common kestrel) when air is blown into them.

The choice of bones used to make these instruments was no accident -- larger birds, with bigger bones that produce deeper sounds, have also been found at the site. The Natufians, the Near Eastern civilisation that occupied this village between 13,000 and 9,700 BC, deliberately selected smaller bones in order to obtain the high-pitched sound needed to imitate these particular raptors. The instruments may have been used for hunting, music or to communicate with the birds themselves. Indeed, it is clear that the Natufians attributed birds with a special symbolic value, as attested by the many ornaments made of talons found at Eynan-Mallaha.

Read more at Science Daily

'Hot Jupiters' may not be orbiting alone

Research led by an Indiana University astronomer challenges longstanding beliefs about the isolation of "hot Jupiters" and proposes a new mechanism for understanding the exoplanets' evolution.

While our Jupiter is far away from the sun, hot Jupiters are gas giant planets that closely orbit stars outside our solar system for an orbital period of less than 10 days. Previous studies suggested they rarely have any nearby companion planets, leading scientists to believe that hot Jupiters formed and evolved through a violent process that expelled other planets from the area as they moved closer to their host stars. The research team's findings reveal that hot Jupiters do not always orbit alone.

"Our research shows that at least a fraction of hot Jupiters cannot form through a violent process," said Songhu Wang, assistant professor of astronomy in the College of Arts and Sciences. "This is a significant contribution to advance our understanding of hot Jupiter formation, which can help us learn more about our own solar system."

Wang presented the results of the research at the June 2023 meeting of the American Astronomical Society in Albuquerque, New Mexico.

Researchers analyzed the full, four-year data set for hot and warm Jupiters from NASA's Kepler Mission. Warm Jupiters have a longer orbital period that ranges from 10 to 300 days. Researchers used transit timing variations to determine that at least 12% of hot Jupiters and 70% of warm Jupiters have a nearby planetary companion orbiting their host stars.

Wang and his collaborators combined their results with existing observational constraints to propose a new framework for explaining the evolution of hot and warm Jupiters and why some have companion planets. They determined that the makeup of hot and warm Jupiter systems depends on the occurrence of gas giants in the system, which impacts how much the planets interact and migrate.

The findings provide a launching point into future research about exoplanets and our solar system's planets.

"The ultimate goal for astronomers is to set our solar system into the bigger picture -- 'Are we unique?'" Wang said. "This helps us to understand why we don't have a hot Jupiter in our solar system."

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Lost giants: New study reveals the abundance decline of African megafauna

Faysal Bibi (Museum für Naturkunde, Berlin) and Juan L. Cantalapiedra (University of Alcalá, Madrid) used measurements of thousands of fossil teeth to reconstruct the size and abundance of African large mammals (>15 kg) over the last 10 million years. Despite many uncertainties affecting preservation in the fossil record, the study revealed a highly similar relationship between an animal's size and its abundance between fossil and extant communities, indicating that fundamental ecological processes governing the structure of living communities are also preserved in the fossil record.

Above 45 kg, the researchers found evidence for decreasing abundance with increasing size, a pattern that aligns with the ecological 'rule of metabolic scaling', whereby larger species have lower population densities compared to smaller ones. A deviation from the predicted ecological pattern was that mammals between ~15 and 45 kg were far less numerous than expected, both in living and fossil communities. They interpreted this as a signature of savanna habitats (where monkeys and small forest-living antelopes are rare).

The big surprise came when the researchers examined how size-abundance distributions changed over time. They discovered that earlier communities, older than ~4 million years ago, had a considerably higher number of large-sized individuals and a greater proportion of total biomass in larger size categories, than did younger communities. The high abundance of large individuals in these fossil African communities -- with some individual elephants reaching sizes over 10 tons -- is unparalleled in ecosystems today. Since that time, there has been a gradual loss of large-sized individuals from the fossil record, reflecting the long-term decline of late Pliocene and Pleistocene large mammal diversity, and resulting in the impoverished and 'miniaturized' communities we know today.

The study confirms recent work arguing for the deep-time antiquity of African megafaunal losses and challenging the idea that the decline of African megafauna was primarily driven by human activities. While the spread of humans across the globe during the late Pleistocene and Holocene (the last ~100,000 years) coincided with major extinction of many large animals, the research supports the idea that megafaunal losses in Africa began much earlier, around 4 million years ago, and long before humans learned to engage in efficient hunting. Instead, the study highlights environmental factors, such as the long-term decrease in global temperatures and the expansion of tropical grasslands, as potential drivers of megafaunal extinctions.

The study also found that the loss of large individuals and the restructuring of biomass distributions in African large mammal communities could have been linked to decreases in primary productivity. Using an established relationship between the types of mammalian tooth shapes (morphological traits) and plant productivity (net primary productivity) today, the researchers calculated productivity for African communities in the past. They found an approximately two-thirds decrease in productivity since the Late Miocene (> 5 million years ago), a pattern observed globally, and that could have significantly diminished the carrying capacity of large mammal communities, leading to reduced diversity and accelerated extinction of large species.

The research opens new avenues for understanding the dynamics of ecosystems and the complex interactions between individuals, species, and their environment. By analyzing fossil abundance data and incorporating size-based approaches, scientists can gain valuable insights into the ecological dynamics underlying extinction.

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How chronic stress drives the brain to crave comfort food

When you're stressed, a high-calorie snack may seem like a comforting go-to. But this combination has an unhealthy downside. According to Sydney scientists, stress combined with calorie-dense 'comfort' food creates changes in the brain that drive more eating, boost cravings for sweet, highly palatable food and lead to excess weight gain.

A team from the Garvan Institute of Medical Research found that stress overrode the brain's natural response to satiety, leading to non-stop reward signals that promote eating more highly palatable food. This occurred in a part of the brain called the lateral habenula, which when activated usually dampens these reward signals.

"Our findings reveal stress can override a natural brain response that diminishes the pleasure gained from eating -- meaning the brain is continuously rewarded to eat," says Professor Herzog, senior author of the study and Visiting Scientist at the Garvan Institute.

"We showed that chronic stress, combined with a high-calorie diet, can drive more and more food intake as well as a preference for sweet, highly palatable food, thereby promoting weight gain and obesity. This research highlights how crucial a healthy diet is during times of stress."

The research was published in the journal Neuron.

From stressed brain to weight gain

While some people eat less during times of stress, most will eat more than usual and choose calorie-rich options high in sugar and fat.

To understand what drives these eating habits, the team investigated in mouse models how different areas in the brain responded to chronic stress under various diets.

"We discovered that an area known as the lateral habenula, which is normally involved in switching off the brain's reward response, was active in mice on a short-term, high-fat diet to protect the animal from overeating. However, when mice were chronically stressed, this part of the brain remained silent -- allowing the reward signals to stay active and encourage feeding for pleasure, no longer responding to satiety regulatory signals," explains first author Dr Kenny Chi Kin Ip from the Garvan Institute.

"We found that stressed mice on a high-fat diet gained twice as much weight as mice on the same diet that were not stressed."

The researchers discovered that at the centre of the weight gain was the molecule NPY, which the brain produces naturally in response to stress. When the researchers blocked NPY from activating brain cells in the lateral habenula in stressed mice on a high-fat diet, the mice consumed less comfort food, resulting in less weight gain.

Driving comfort eating

The researchers next performed a 'sucralose preference test' -- allowing mice to choose to drink either water or water that had been artificially sweetened.

"Stressed mice on a high-fat diet consumed three times more sucralose than mice that were on a high-fat diet alone, suggesting that stress not only activates more reward when eating but specifically drives a craving for sweet, palatable food," says Professor Herzog.

"Crucially, we did not see this preference for sweetened water in stressed mice that were on a regular diet."

Stress overrides healthy energy balance

"In stressful situations it's easy to use a lot of energy and the feeling of reward can calm you down -- this is when a boost of energy through food is useful. But when experienced over long periods of time, stress appears to change the equation, driving eating that is bad for the body long term," says Professor Herzog.

The researchers say their findings identify stress as a critical regulator of eating habits that can override the brain's natural ability to balance energy needs.

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