Astronomers discover newborn galaxies with the James Webb Space Telescope

With the launch of the James Webb Space Telescope, astronomers are now able to peer so far back in time that we are approaching the epoch where we think that the first galaxies were created. Throughout most of the history of the Universe, galaxies seemingly tend to follow a tight relation between how many stars they have formed, and how many heavy elements they have formed. But for the first time we now see signs that this relation between the amount of stars and elements does not hold for the earliest galaxies. The reason is likely that these galaxies simply are in the process of being created, and have not yet had the time to create the heavy elements.

The Universe is teeming with galaxies -- immense collections of stars and gas -- and as we peer deep into the cosmos, we see them near and far. Because the light has spent more time reaching us, the farther away a galaxy is, we are essentially looking back through time, allowing us to construct a visual narrative of their evolution throughout the history of the Universe.

Observations have shown us that galaxies through the last 12 billion years -- that is, 5/6 of the age of the Universe -- have been living their life in a form of equilibrium: There appears to be a fundamental, tight relation between on one hand how many stars they have formed, and on the other hand how many heavy elements they have formed. In this context, "heavy elements," means everything heavier than hydrogen and helium.

This relation makes sense, because the Universe consisted originally only of these two lightest elements. All heavier elements, such as carbon, oxygen, and iron, was created later by the stars.

James Webb peers deeper

The very first galaxies should therefore be "unpolluted" by heavy elements. But until recently we haven't been able to look so far back in time. In addition to being far away, the reason is that the longer light travels through space, the redder it becomes. For the most distant galaxies you have to look all the way into the infrared part of the spectrum, and only with the launch of James Webb did we have a telescope big and sensitive enough to see so far.

And the space telescope did not disappoint: Several has James Webb broken its own record for the most distant galaxy, and now it finally seems that we are reaching the epoch where some of the very first galaxies were created.

In a new study, published today in the scientific journal Nature Astronomy, af team of astronomers from the Danish research center Cosmic Dawn Center at the Niels Bohr Institute and DTU Space in Copenhagen, has discovered what seems indeed to be some of the very first galaxies which are still in the process of being formed.

"Until recently it has been near-impossible to study how the first galaxies are formed in the early Universe, since we simply haven't had the adequate instrumentation. This has now changed completely with the launch of James Webb," says Kasper Elm Heintz, leader of the study and assistant professor at the Cosmic Dawn Center.

Fundamental relation breaks down

The relationship between the total stellar mass of the galaxy and the amount of heavy elements is a bit more complex than that. How fast the galaxy produces new stars also has something to say. But if you correct for that, you get a beautiful, linear relationship: The more massive the galaxy, the more heavy elements.

But this relation is now being challenged by the latest observations.

"When we analyzed the light from 16 of these first galaxies, we saw that they had significantly less heavy elements, compared to what you'd expect from their stellar masses and the amount of new stars they produced," says Kasper Elm Heintz.

In fact the galaxies turned out to have, on average, four times less amounts of heavy elements that in the later Universe. These results are in stark contrast to the current model where galaxies evolve in a form of equilibrium throughout most of the history of the Universe.

Predicted by theories

The result is not entirely surprising though. Theoretical models of galaxy formation, based on detailed computer programs, do predict something similar. But now we've seen it!

The explanation, as proposed by the autors in the article, is simply that we are witnessing galaxies in the process of being created. Gravity has gathered the first clumps of gas, which have begun to form stars.

If the galaxies then lived their lives undisturbed, the stars would quickly enrich them with heavy elements. But in between the galaxies at that time were large amounts of fresh, unpolluted gas, streaming down to the galaxies faster than the stars can keep up.

"The result gives us the first insight into the earliest stages of galaxy formation which appear to be more intimately connected with the gas in between the galaxies than we thought.

This is one of the first James Webb observations on this topic, so we're still waiting to see what the larger, more comprehensive observations that are currently being carried out can tell us.

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Alarming results from world first study of two decades of global smoke pollution

The world's first study of the increase in pollution from landscape fires across the globe over the past two decades reveals that over 2 billion people are exposed to at least one day of potentially health-impacting environmental hazard annually -- a figure that has increased by 6.8 per cent in the last ten years.

The study highlights the severity and scale of the landscape fire-sourced air pollution, its increased impact on the world's population and associated rise in public health risk. Exposure to fire-sourced air pollution has many adverse health impacts, including increased mortality and morbidity and a global worsening of cardiorespiratory conditions and mental health.

The study, published today (20 September) in Nature led by Australian scientists, estimated the global daily air pollution from all fires from 2000 to 2019 -- finding that 2.18 billion people were exposed to at least one day of substantial landscape fire air pollution in each year, with each person in the world having on average 9.9 days of exposure per year, an increase of 2.1 per cent in the last decade. It also found that exposure levels in low-income countries were about four-fold higher than in high income countries.

Led by Professors Yuming Guo and Shanshan Li, from Monash University's School of Population Health and Preventive Medicine, the study also found that the exposure levels of PM2.5 were particularly high in Central Africa, Southeast Asia, South America and Siberia. The study also looked at global landscape fire-sourced ozone, an important fire-related pollutant has only been estimated for United States.

In the study, landscape fires refer to any fires burning in natural and cultural landscapes, e.g. natural and planted forest, shrub, grass, pastures, agricultural lands and peri-urban areas, including both planned or controlled fires (e.g., prescribed burns, agricultural fires) and wildfires (defined as uncontrolled or unplanned fires burning in wildland vegetation).

The comprehensive assessment of the global population exposures to fire-sourced PM2.5 and ozone during 2000-2019 was calculated using a machine learning approach with inputs from chemical transport models, ground-based monitoring stations, and gridded weather data.

The recent pollution from the Canadian wildfires that spread smoke across North America highlighted the increase in severity and frequency of landscape fires due to climate change. According to Professor Guo, no study to date has looked at the long-range effect of this increase in landscape fires globally and wildfires often impact remote areas where there are few or no air quality monitoring stations. In addition, in many low-income countries, there are no air quality monitoring stations even in urban areas.

"The exposure to air pollution caused by landscape fire smoke travelling hundreds and sometimes even thousands of kilometres can affect much larger populations, and cause much larger public health risks," he said.

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Scientists regenerate neurons that restore walking in mice after paralysis from spinal cord injury

In a new study in mice, a team of researchers from UCLA, the Swiss Federal Institute of Technology, and Harvard University have uncovered a crucial component for restoring functional activity after spinal cord injury. The neuroscientists have shown that re-growing specific neurons back to their natural target regions led to recovery, while random regrowth was not effective.

In a 2018 study published in Nature, the team identified a treatment approach that triggers axons -- the tiny fibers that link nerve cells and enable them to communicate -- to regrow after spinal cord injury in rodents. But even as that approach successfully led to the regeneration of axons across severe spinal cord lesions, achieving functional recovery remained a significant challenge.

For the new study, published this week in Science, the team aimed to determine whether directing the regeneration of axons from specific neuronal subpopulations to their natural target regions could lead to meaningful functional restoration after spinal cord injury in mice. They first used advanced genetic analysis to identify nerve cell groups that enable walking improvement after a partial spinal cord injury.

The researchers then found that merely regenerating axons from these nerve cells across the spinal cord lesion without specific guidance had no impact on functional recovery. However, when the strategy was refined to include using chemical signals to attract and guide the regeneration of these axons to their natural target region in the lumbar spinal cord, significant improvements in walking ability were observed in a mouse model of complete spinal cord injury.

"Our study provides crucial insights into the intricacies of axon regeneration and requirements for functional recovery after spinal cord injuries," said Michael Sofroniew, MD, PhD, professor of neurobiology at the David Geffen School of Medicine at UCLA and a senior author of the new study. "It highlights the necessity of not only regenerating axons across lesions but also of actively guiding them to reach their natural target regions to achieve meaningful neurological restoration."

The authors say understanding that re-establishing the projections of specific neuronal subpopulations to their natural target regions holds significant promise for the development of therapies aimed at restoring neurological functions in larger animals and humans. However, the researchers also acknowledge the complexity of promoting regeneration over longer distances in non-rodents, necessitating strategies with intricate spatial and temporal features. Still, they conclude that applying the principles laid out in their work "will unlock the framework to achieve meaningful repair of the injured spinal cord and may expedite repair after other forms of central nervous system injury and disease."

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Astronomers find abundance of Milky Way-like Galaxies in early Universe, rewriting cosmic evolution theories

Galaxies from the early Universe are more like our own Milky Way than previously thought, flipping the entire narrative of how scientists think about structure formation in the Universe, according to new research published today.

Using the James Webb Space Telescope (JWST), an international team of researchers including those at The University of Manchester and University of Victoria in Canada discovered that galaxies like our own Milky Way dominate throughout the universe and are surprisingly common.

These galaxies go far back in the Universe's history with many of these galaxies forming 10 billion years ago or longer.

The Milky Way is a typical 'disk' galaxy, which a shape similar to a pancake or compact disk, rotating about its centre and often containing spiral arms. These galaxies are thought to be the most common in the nearby Universe and might be the types of galaxies where life can develop given the nature of their formation history.

However, astronomers previously considered that these types of galaxies were too fragile to exist in the early Universe when galaxy mergers were more common, destroying what we thought was their delicate shapes.

The new discovery, published today in the Astrophysical Journal, finds that these 'disk' galaxies are ten times more common than what astronomers believed based on previous observations with the Hubble Space Telescope.

Christopher Conselice, Professor of Extragalactic Astronomy at The University of Manchester, said: "Using the Hubble Space Telescope we thought that disk galaxies were almost non-existent until the Universe was about six billion years old, these new JWST results push the time these Milky Way-like galaxies form to almost the beginning of the Universe."

The research completely overturns the existing understanding of how scientists think our Universe evolves, and the scientists say new ideas need to be considered.

Lead author, Leonardo Ferreira from the University of Victoria, said: "For over 30 years it was thought that these disk galaxies were rare in the early Universe due to the common violent encounters that galaxies undergo. The fact that JWST finds so many is another sign of the power of this instrument and that the structures of galaxies form earlier in the Universe, much earlier in fact, than anyone had anticipated. "

It was once thought that disk galaxies such as the Milky Way were relatively rare through cosmic history, and that they only formed after the Universe was already middle aged.

Previously, astronomers using the Hubble Space Telescope believed that galaxies had mostly irregular and peculiar structures that resemble mergers. However, the superior abilities of JWST now allows us to see the true structure of these galaxies for the first time.

The researchers say that this is yet another sign that 'structure' in the Universe forms much quicker than anyone had anticipated.

Professor Conselice continues: "These JWST results show that disk galaxies like our own Milky Way, are the most common type of galaxy in the Universe. This implies that most stars exist and form within these galaxies which is changing our complete understanding of how galaxy formation occurs. These results also suggest important questions about dark matter in the early Universe which we know very little about."

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How to tackle the global deforestation crisis

Imagine if France, Germany, and Spain were completely blanketed in forests -- and then all those trees were quickly chopped down. That's nearly the amount of deforestation that occurred globally between 2001 and 2020, with profound consequences.

Deforestation is a major contributor to climate change, producing between 6 and 17 percent of global greenhouse gas emissions, according to a 2009 study. Meanwhile, because trees also absorb carbon dioxide, removing it from the atmosphere, they help keep the Earth cooler. And climate change aside, forests protect biodiversity.

"Climate change and biodiversity make this a global problem, not a local problem," says MIT economist Ben Olken. "Deciding to cut down trees or not has huge implications for the world."

But deforestation is often financially profitable, so it continues at a rapid rate. Researchers can now measure this trend closely: In the last quarter-century, satellite-based technology has led to a paradigm change in charting deforestation. New deforestation datasets, based on the Landsat satellites, for instance, track forest change since 2000 with resolution at 30 meters, while many other products now offer frequent imaging at close resolution.

"Part of this revolution in measurement is accuracy, and the other part is coverage," says Clare Balboni, an assistant professor of economics at the London School of Economics (LSE). "On-site observation is very expensive and logistically challenging, and you're talking about case studies. These satellite-based data sets just open up opportunities to see deforestation at scale, systematically, across the globe."

Balboni and Olken have now helped write a new paper providing a road map for thinking about this crisis. The open-access article, "The Economics of Tropical Deforestation," appears this month in the Annual Review of Economics. The co-authors are Balboni, a former MIT faculty member; Aaron Berman, a PhD candidate in MIT's Department of Economics; Robin Burgess, an LSE professor; and Olken, MIT's Jane Berkowitz Carlton and Dennis William Carlton Professor of Microeconomics. Balboni and Olken have also conducted primary research in this area, along with Burgess.

So, how can the world tackle deforestation? It starts with understanding the problem.

Replacing forests with farms

Several decades ago, some thinkers, including the famous MIT economist Paul Samuelson in the 1970s, built models to study forests as a renewable resource; Samuelson calculated the "maximum sustained yield" at which a forest could be cleared while being regrown. These frameworks were designed to think about tree farms or the U.S. national forest system, where a fraction of trees would be cut each year, and then new trees would be grown over time to take their place.

But deforestation today, particularly in tropical areas, often looks very different, and forest regeneration is not common.

Indeed, as Balboni and Olken emphasize, deforestation is now rampant partly because the profits from chopping down trees come not just from timber, but from replacing forests with agriculture. In Brazil, deforestation has increased along with agricultural prices; in Indonesia, clearing trees accelerated as the global price of palm oil went up, leading companies to replace forests with palm tree orchards.

All this tree-clearing creates a familiar situation: The globally shared costs of climate change from deforestation are "externalities," as economists say, imposed on everyone else by the people removing forest land. It is akin to a company that pollutes into a river, affecting the water quality of residents.

"Economics has changed the way it thinks about this over the last 50 years, and two things are central," Olken says. "The relevance of global externalities is very important, and the conceptualization of alternate land uses is very important." This also means traditional forest-management guidance about regrowth is not enough. With the economic dynamics in mind, which policies might work, and why?

The search for solutions

As Balboni and Olken note, economists often recommend "Pigouvian" taxes (named after the British economist Arthur Pigou) in these cases, levied against people imposing externalities on others. And yet, it can be hard to identify who is doing the deforesting.

Instead of taxing people for clearing forests, governments can pay people to keep forests intact. The UN uses Payments for Environmental Services (PES) as part of its REDD+ (Reducing Emissions from Deforestation and forest Degradation) program. However, it is similarly tough to identify the optimal landowners to subsidize, and these payments may not match the quick cash-in of deforestation. A 2017 study in Uganda showed PES reduced deforestation somewhat; a 2022 study in Indonesia found no reduction; another 2022 study, in Brazil, showed again that some forest protection resulted.

"There's mixed evidence from many of these [studies]," Balboni says. These policies, she notes, must reach people who would otherwise clear forests, and a key question is, "How can we assess their success compared to what would have happened anyway?"

Some places have tried cash transfer programs for larger populations. In Indonesia, a 2020 study found such subsidies reduced deforestation near villages by 30 percent. But in Mexico, a similar program meant more people could afford milk and meat, again creating demand for more agriculture and thus leading to more forest-clearing.

At this point, it might seem that laws simply banning deforestation in key areas would work best -- indeed, about 16 percent of the world's land overall is protected in some way. Yet the dynamics of protection are tricky. Even with protected areas in place, there is still "leakage" of deforestation into other regions.

Still more approaches exist, including "nonstate agreements," such as the Amazon Soy Moratorium in Brazil, in which grain traders pledged not to buy soy from deforested lands, and reduced deforestation without "leakage."

Also, intriguingly, a 2008 policy change in the Brazilian Amazon made agricultural credit harder to obtain by requiring recipients to comply with environmental and land registration rules. The result? Deforestation dropped by up to 60 percent over nearly a decade.

Politics and pulp

Overall, Balboni and Olken observe, beyond "externalities," two major challenges exist. One, it is often unclear who holds property rights in forests. In these circumstances, deforestation seems to increase. Two, deforestation is subject to political battles.

For instance, as economist Bard Harstad of Stanford University has observed, environmental lobbying is asymmetric. Balboni and Olken write: "The conservationist lobby must pay the government in perpetuity … while the deforestation-oriented lobby need pay only once to deforest in the present." And political instability leads to more deforestation because "the current administration places lower value on future conservation payments."

Even so, national political measures can work. In the Amazon from 2001 to 2005, Brazilian deforestation rates were three to four times higher than on similar land across the border, but that imbalance vanished once the country passed conservation measures in 2006. However, deforestation ramped up again after a 2014 change in government. Looking at particular monitoring approaches, a study of Brazil's satellite-based Real-Time System for Detection of Deforestation (DETER), launched in 2004, suggests that a 50 percent annual increase in its use in municipalities created a 25 percent reduction in deforestation from 2006 to 2016.

How precisely politics matters may depend on the context. In a 2021 paper, Balboni and Olken (with three colleagues) found that deforestation actually decreased around elections in Indonesia. Conversely, in Brazil, one study found that deforestation rates were 8 to 10 percent higher where mayors were running for re-election between 2002 and 2012, suggesting incumbents had deforestation industry support.

"The research there is aiming to understand what the political economy drivers are," Olken says, "with the idea that if you understand those things, reform in those countries is more likely."

Looking ahead, Balboni and Olken also suggest that new research estimating the value of intact forest land intact could influence public debates. And while many scholars have studied deforestation in Brazil and Indonesia, fewer have examined the Democratic Republic of Congo, another deforestation leader, and sub-Saharan Africa.

Deforestation is an ongoing crisis. But thanks to satellites and many recent studies, experts know vastly more about the problem than they did a decade or two ago, and with an economics toolkit, can evaluate the incentives and dynamics at play.

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Migratory birds can be taught to adjust to climate change

One result of climate change is that spring is arriving earlier. However, migratory birds are not keeping up with these developments and arrive too late for the peak in food availability when it is time for breeding. By getting the birds to fly a little further north, researchers in Lund, Sweden, and the Netherlands have observed that these birds can give their chicks a better start in life.

Global warming is causing problems for birds in Sweden and elsewhere. Warmer springs mean that caterpillars hatch, grow and pupate earlier compared with just a few decades ago. This has consequences for birds that cannot eat caterpillars that have entered the pupal stage. Therefore, when the food supply runs out at an ever earlier time in the spring, more and more chicks starve during the breeding season. This is a big problem for migratory birds that spend winters in Africa, as they do not know how early spring arrives in Sweden. Could the problem be solved if the migratory birds simply came home and started breeding earlier?

"It seems that our non-migratory birds are doing this to a certain extent. But, of course, they are present and can feel how early spring will come. We thought that perhaps the migratory birds could fly further north until they find a place with suitable well-developed caterpillars," says Jan-Åke Nilsson, biology researcher at Lund University in Sweden.

To test this in practice, the researchers decided to help some Pied Flycatchers along the way. The biologists caught Pied Flycatchers that had arrived prior to breeding in the Netherlands. The birds were then driven during the night to Vombs Fure, an area of pine forest outside Lund in Skåne, where they were released. The peak of caterpillar availability in Skåne is about two weeks later than in the Netherlands -- a distance of around 600 kilometres that a Pied Flycatcher could cover in just two nights.

"The birds that were given a lift from the Netherlands to Skåne synchronised very well with the food peak! As they started to breed about 10 days earlier the "Swedish" Pied Flycatchers they had a dramatically better breeding success than the Swedish ones as well as a better success than the Pied Flycatchers that remained in the Netherlands," says Jan-Åke Nilsson.

In addition, it was shown that the chicks of the Dutch Pied Flycatchers that had received migration assistance did not stop in the Netherlands when they returned after their first spring migration. Instead, they continued on to the area of pine forest outside Lund where they were born. Furthermore, they arrived earlier than the Swedish Pied Flycatchers and thereby had more well-fed chicks at Vombs Fure the year after the researchers gave the Pied Flycatchers a helping hand to find Skåne.

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Probing the deep genetic structure of Africa

Using ancestry decomposition techniques an international research team has revealed a deeply divergent ancestry among admixed populations from the Angolan Namib desert. This unique genetic heritage brings the researchers closer to understanding the distribution of genetic variation in the broader region of southern Africa before the spread of food production.

Africa is the birthplace of modern humans and the continent with the highest level of genetic diversity. While ancient DNA studies are revealing some aspects of the genetic structure of Africa before the spread of food production, issues concerning DNA preservation have limited the insights from ancient DNA.

Hoping to find clues in modern populations, researchers from a Portuguese-Angolan TwinLab ventured into the Angolan Namib desert -- a remote, multi-ethnic region where different traditions met. "We were able to locate groups which were thought to have disappeared more than 50 years ago," states Jorge Rocha, a population geneticist from Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO, University of Porto) who led the fieldwork, together with Angolan anthropologists Samuel and Teresa Aço from the Centro de Estudos do Deserto (CEDO).

Among the communities the team encountered are the Kwepe, a pastoral group who used to speak a language known as Kwadi. "Kwadi was a click-language that shared a common ancestor with the Khoe languages spoken by foragers and herders across southern Africa," explains Anne-Maria Fehn, a linguist from CIBIO who participated in the fieldwork and was able to interview what may well be the last two speakers of Kwadi. "Khoe-Kwadi languages have been linked to a prehistoric migration of eastern African pastoralists," adds Rocha, whose research focuses on southern African population history. In addition, the team contacted Bantu-speaking groups that are part of the dominant pastoral tradition of southwest Africa, as well as marginalized groups whose origins have been associated with a foraging tradition, distinct from that of the neighboring Kalahari peoples, and whose original language was supposedly lost.

Modern DNA research can complement ancient DNA studies

The team's new study shows that the inhabitants of the Angolan Namib are quite divergent from other modern populations but also highly structured among themselves. "In agreement with our previous studies on the maternally-inherited DNA, most genome-wide diversity segregates according to socio-economic status. A lot of our efforts were placed in understanding how much of this local variation and global excentricity was caused by genetic drift -- a random process that disproportionally affects small populations -- and by admixture from vanished populations," says Sandra Oliveira, a researcher at the University of Bern in Switzerland who worked with these populations during her PhD and post-doc studies with Rocha and Mark Stoneking at CIBIO and the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) in Leipzig, Germany. The team demonstrated that besides the high impact of genetic drift, which contributed to differences among neighboring groups of different socio-economic status, the descendants of Kwadi speakers and the marginalized communities of the Namib Desert retain a unique Pre-Bantu ancestry that is only found in populations from the Namib desert.

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New Mars gravity analysis improves understanding of possible ancient ocean

The first use of a novel method of analyzing Mars' gravitational force supports the idea that the planet once had an extensive northern ocean.

In doing so, the method defines the scope of what scientists refer to as the northern Martian paleo-ocean in more detail.

The work was published in July in the journal Icarus, which is affiliated with the American Astronomical Society's Division for Planetary Sciences.

The research was led by Jaroslav Klokočník, professor emeritus at the Astronomical Institute of the Czech Academy of Sciences. Gunther Kletetschka, associate research professor at the University of Alaska Fairbanks Geophysical Institute, is among the three co-authors. Kletetschka is also affiliated with Charles University in the Czech Republic.

"A lot of people are excited about water on Mars because there may be life forms that once existed on Mars or maybe exist today in some bacterial form," Kletetschka said. "We can use this gravity approach to look for water on Mars, because we have done it already on Earth.

"In an area of northern Africa, for example, this gravity approach found a shoreline of a long-ago lake, and its finding was consistent with the archaeological evidence indicating a shoreline of that lake," he said.

The authors write that analyzing the gravity aspects of Mars to better understand the planet improves upon prior approaches. They note that it can "provide complete information with a better insight of the celestial body, applicable in geology, geophysics, hydrology, glaciology and other disciplines."

The work by Kletetschka and colleagues differs from the traditional approach of mapping a surface based on gravity anomalies alone.

Gravity anomalies are areas of greater or weaker gravitational force exerted by a planetary body's surface features. A mountain would exert a greater gravitational force because it has a higher concentration of mass than would be expected on a planet without surface features. Ocean basins and trenches would have less gravitational force.

In their Mars research, the authors used a process developed by Klokočník that analyzes gravity aspects calculated from gravity anomaly measurements. Gravity aspects are mathematical products that characterize the gravity anomalies.

They also used topographic data from the Mars Orbital Laser Altimeter instrument aboard NASA's Mars Global Surveyor, which launched in November 1996 and mapped the planet for 4 ½ years.

Klokočník used that approach to confirm earlier research about the existence of extensive paleolakes or paleoriver systems under the Saharan sands on Earth. His 2017 research paper also suggested a part of the Grand Egyptian Sand Sea as another candidate for a paleolake.

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Sustainable energy for aviation: What are our options?

Scientists and industry leaders worldwide are looking for answers on how to make aviation sustainable by 2050 and choosing a viable sustainable fuel is a major sticking point. Phil Ansell, aerospace engineer at the University of Illinois Urbana-Champaign, took a full inventory of the options to make a data-driven assessment about how they stack up in comparison. He reviewed over 300 research projects from across different sectors, not just aerospace, to synthesize the ideas and draw conclusions to help direct the dialogue about sustainable aviation toward a permanent solution.

Ansell said several key energy carriers emerged, including bio jet fuel pathways for synthetic kerosene, power-to-liquid pathways for synthetic kerosene, liquid hydrogen, ammonia, liquid natural gas, ethanol, methanol, and battery electric systems. Ansell compared each of them to conventional fossil-derived aviation turbine fuel.

For each of the alternate fuels Ansell addressed factors such as how their material properties impact aircraft performance and fuel handling, emissions, cost and scalability, and resource and land requirements, as well as social impacts, which can be difficult to measure.

"Let's face it, if we want to do this at scale, we need all three pillars of the environmental, economic, and societal contributions, to make that energy carrier sustainable, and every stakeholder in the value chain sees the challenges differently," Ansell said. "Because the production and infrastructure costs required to adopt an alternative fuel source are significant, people think we can only pick one, the biggest contenders being bio jet fuel and hydrogen," Ansell said. "But the choice doesn't have to be mutually exclusive. For example, we can use hydrogen to produce synthetic aviation fuels like the power-to-liquid pathway or use biomass to produce hydrogen."

Ansell admitted this is not what he typically studies, but his research and teaching areas in aircraft design and aerodynamics must consider where the energy will come from to make flight possible. So, for any fuel associated with a bio aspect Ansell had to look at the stresses it might create for crops.

"I leaned on a lot of the observations from the community, especially for the land use change question," he said. "It is so driven case by case. Making a broad assessment doesn't do it justice, because land use changes depend on their location."

Ansell said he has been working with hydrogen for several years and battery/electric systems before that, so he needed to remain objective and all the data to drive the conclusion.

"About eight years ago, I realized that battery systems are a pie-in-the-sky solution. The technology challenge is insurmountable. The weight and volume required for batteries is too difficult to close. I think my biases were from the fact that I've been studying hydrogen for a long time, and I think it has real potential. That's one of the conclusions I arrived at from the data, and I think I would have learned that independently."

Ansell said hydrogen presents infrastructural and integration challenges, unique to the aircraft platform and unique to the cryogenic handling of fuel on aircraft.

"The technological challenges of hydrogen are very solvable. And I can say that with confidence because we've done it as a society." He referred to Tupolev 155, a commercial scale aircraft which was flown by the former Soviet Union with liquid hydrogen in the 1980s on a relevant airframe. Even earlier experimental studies were conducted by NASA. "It will take a bit longer to implement at scale, but it's doable."

In the study, Ansell examined numerous options to produce biofuel from just about anything, from municipal waste to seaweed and algae.

"Basically, anything that you can burn, create energy from, decompose, can be turned into a jet fuel. We've already been using corn to produce ethanol. But if you were to take corn, ferment it, then turn that ethanol into jet fuel, you now have lost the ability to feed people or animals that corn. This is one of the challenges of all first-generation biofuels."

He said people are trying to use the stover, the parts of a corn plant left on the ground after harvesting to make fuel. Corn stover is full of sugar but it's difficult to extract.

Why is an aerospace engineer studying feedstocks?

"I want to be able to know enough to interact with scientists who are tackling these options," Ansell said. "And it's important that the aviation community understands where the challenges exist. We need to draw the lines between the aircraft as a system, the aircraft operating in an airspace, and how that connects with energy. With a goal of net zero CO2 by 2050, I want the aviation community to recognize how big of a task this is.

"As a society, we are often attentive to challenges that are right in front of us, with limited foresight to plan for the future. So even as it pertains to the greenhouse gas effect, we still don't have an appreciation for the long-term sense of the damage that produces. We have other immediate concerns to spend money on. But without that foresight, we are going to struggle and regret decisions not to make investments and not to take seriously these aviation sustainability challenges when we still had time."Again, Ansell stressed that it might not need to be a one-fuel-fits-all solution. In fact, countries may need different strategies, different rates of implementation, and adoption of renewables, based on their own resources. For example, Denmark doesn't have as much land as the U.S. and so is making great use of offshore wind turbine platforms.

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RNA for the first time recovered from an extinct species

A new study shows the isolation and sequencing of more than a century-old RNA molecules from a Tasmanian tiger specimen preserved at room temperature in a museum collection. This resulted in the reconstruction of skin and skeletal muscle transcriptomes from an extinct species for the first time. The researchers note that their findings have relevant implications for international efforts to resurrect extinct species, including both the Tasmanian tiger and the woolly mammoth, as well as for studying pandemic RNA viruses.

The Tasmanian tiger, also known as the thylacine, was a remarkable apex carnivorous marsupial that was once distributed all across the Australian continent and the island of Tasmania. This extraordinary species found its final demise after European colonization, when it was declared as an agricultural pest and a bounty of £1 per each full-grown animal killed was set by 1888. The last known living Tasmanian tiger died in captivity in 1936 at the Beaumaris Zoo in Hobart, Tasmania.

Recent efforts in de-extinction have focused on the Tasmanian tiger, as its natural habitat in Tasmania is still mostly preserved, and its reintroduction could help recovering past ecosystem equilibriums lost after its final disappearance. However, reconstructing a functional living Tasmanian tiger not only requires a comprehensive knowledge of its genome (DNA) but also of tissue-specific gene expression dynamics and how gene regulation worked, which are only attainable by studying its transcriptome (RNA).

"Resurrecting the Tasmanian tiger or the woolly mammoth is not a trivial task, and will require a deep knowledge of both the genome and transcriptome regulation of such renowned species, something that only now is starting to be revealed," says Emilio Mármol, the lead author of a study recently published in the Genome Research journal by researchers at SciLifeLab in collaboration with the Centre for Palaeogenetics, a joint venture between the Swedish Museum of Natural History and Stockholm University.

RNA molecules recovered from the Tasmanian tiger

The researchers behind this study have sequenced, for the first time, the transcriptome of the skin and skeletal muscle tissues from a 130-year-old desiccated Tasmanian tiger specimen preserved at room temperature in the Swedish Museum of Natural History in Stockholm. This led to the identification of tissue-specific gene expression signatures that resemble those from living extant marsupial and placental mammals.

The recovered transcriptomes were of such good quality that it was possible to identify muscle- and skin-specific protein coding RNAs, and led to the annotation of missing ribosomal RNA and microRNA genes, the later following MirGeneDB recommendations.

"This is the first time that we have had a glimpse into the existence of thylacine-specific regulatory genes, such as microRNAs, that got extinct more than one century ago," says Marc R. Friedländer, Associate Professor at the Department of Molecular Biosciences, The Wenner-Gren Institute at Stockholm University and SciLifeLab.

This pioneering study opens up new exciting opportunities and implications for exploring the vast collections of specimens and tissues stored at museums across the globe, where RNA molecules might await to be uncovered and sequenced.

"In the future, we may be able to recover RNA not only from extinct animals, but also RNA virus genomes such as SARS-CoV2 and their evolutionary precursors from the skins of bats and other host organisms held in museum collections," says Love Dalén, Professor of evolutionary genomics at Stockholm University and the Centre for Palaeogenetics.

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Prehistoric fish fills 100 million year gap in evolution of the skull

A 455-million-year-old fossil fish provides a new perspective on how vertebrates evolved to protect their brains, a study has found.

In a paper published in Nature today (Wednesday 20th September), researchers from the University of Birmingham, Naturalis Biodiversity Centre in Leiden, Netherlands; and the Natural History Museum have pieced together the skull of Eriptychius americanus.

The research, funded by the Leverhulme Trust, suggests that the ancient jawless fish found in ancient deposits in Colorado, USA has a skull unlike that of any previously seen, and fills a gap currently spanning 100 million years in the evolutionary history of the vertebrate skull.

Using computed tomography, a form of x-ray technique, scientists recreated a detailed 3D representation of the skull of Eriptychius and is the first time that such a comprehensive recreation has been done on the specimen which was collected in the 1940s, originally described in the 1960s and is housed in the Field Museum of Natural History, Chicago.

This ancient fish had separated, independent cartilages encasing the brain, rather than the solid bone or cartilage structure of jawless and jawed fish that followed it.

While later specieshave a fully bound cage of cartilage that holds the brain, these results suggest that the early evolution of structures to separate the brain from other parts of the head may have begun with Eriptychius.

Dr Ivan Sansom, Senior Lecturer in Palaeobiology at the University of Birmingham and senior author of the paper said:

"These are tremendously exciting results that may reveal the early evolutionary history of how primitive vertebrates protected their brains. Eriptychius americanus appears to be the first evidence for a series of cartilages separating the brain from the rest of the head. This study emphasises the importance of museum collections and the application of new techniques in studying them."

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Tag team of the James Webb Space Telescope and ALMA captures the core of the most distant galaxy protocluster

An international research team led by Assistant Professor Takuya Hashimoto (University of Tsukuba, Japan) and Researcher Javier Álvarez-Márquez (El Centro de Astrobiología (CAB, CSIC-INTA), Spain) has used the James Webb Space Telescope and the Atacama Large Millimeter/submillimeter Array to observe the most distant galaxy protocluster to date, 13.14 billion light-years away. The team has successfully captured the "core region" of the galaxy protocluster, which corresponds to a metropolitan area with a particularly high number density of galaxies.

The team has revealed that many galaxies are concentrated in a small area and that the growth of galaxies is accelerated. Furthermore, the team used simulations to predict the future of the metropolitan area and found that the region will merge into one larger galaxy within tens of millions of years. These results are expected to provide important clues regarding the birth and growth of galaxies.

The study of how individual stars are born and die in galaxies, how new stars are born from remnants of old stars, and how galaxies themselves grow are important themes in astronomy, as they provide insight into our roots in the Universe. Galaxy clusters, one of the largest structures in the Universe, are the assembly of more than 100 galaxies which are bound together through mutual gravitational force. Observations of nearby galaxies have shown that the growth of a galaxy depends on its environment in the sense that mature stellar populations are commonly seen in regions where galaxies are densely collected. This is referred to as the "environment effect." Although the environment effect has been considered an important piece to understand galaxy formation and evolution, it is not well known when the effect initiated in the history of the Universe. One of the keys to understanding this is to observe the ancestors of galaxy clusters shortly after the birth of the Universe; known as galaxy protoclusters (hereafter protoclusters), these are assemblies of about 10 distant galaxies. Fortunately, astronomy allows us to observe the distant Universe as it was in the past. For example, light from a galaxy 13 billion light-years away takes 13 billion years to reach Earth, so what we observe now is what that galaxy looked like 13 billion years ago. However, light that travels 13 billion light-years becomes fainter, so the telescopes that observe it must have high sensitivity and spatial resolution.

An international research team led by Assistant Professor Takuya Hashimoto (University of Tsukuba, Japan) and researcher Javier Álvarez-Márquez (Spanish Center for Astrobiology) has used the James Webb Space Telescope (JWST, observing visible and infrared light) and the Atacama Large Millimeter/submillimeter Array (ALMA, observing radio waves) to study the "core region" of the protocluster A2744z7p9OD. The protocluster A2744z7p9OD had been announced as the most distant proto-cluster at 13.14 billion light-years away based on observations with JWST by another research group. "However, we have not been able to observe the entire core region, the metropolitan area, with the largest number of galaxy candidates in this protocluster. It was unclear whether the environmental effects of galaxies had begun in this protocluster. So we decided to focus our research on the core region," says Hashimoto.

The research team first observed the core region of this protocluster using JWST. Using NIRSpec, an instrument that observes spectra at wavelengths ranging from visible to near-infrared, the team made integral field spectroscopy observations that can simultaneously acquire spectra from all locations within the field of view. The team has successfully detected ionized oxygen-ion light ([OIII] 5008 Å) from four galaxies in a quadrangle region measuring 36,000 light-years along a side, which is equivalent to half the radius of the Milky Way galaxy (. Based on the redshift of this light (the elongation of the wavelength due to the cosmic expansion), the distance of the four galaxies from the Earth was identified as 13.14 billion light years. "I was surprised when we identified four galaxies by detecting oxygen-ion emission at almost the same distance. The 'candidate galaxies' in the core region were indeed members of the most distant protocluster," says Yuma Sugahara (Waseda/NAOJ), who led the JWST data analysis.

In addition, the research team paid attention to the archival ALMA data, which had already been acquired for this region. The data captures radio emission from cosmic dust in these distant galaxies. As a result of analyses, they detected dust emissions from three of the four galaxies. This is the first detection of dust emission in member galaxies of a protocluster this far back in time. Cosmic dust in galaxies is thought to be supplied by supernova explosions at the end of the evolution of massive stars in the galaxies, which provide the material for new stars. Therefore, the presence of large amounts of dust in a galaxy indicates that many of the first-generation stars in the galaxy have already completed their lives and that the galaxy is growing. Professor Luis Colina (El Centro de Astrobiología (CAB, CSIC-INTA)) describes the significance of the results: "Emission from cosmic dust was not detected in member galaxies of the protocluster outside the core region. The results indicate that many galaxies are clustered in a small region and that galaxy growth is accelerated, suggesting that environmental effects existed only ~700 million years after the Big Bang."

Furthermore, the research team conducted a galaxy formation simulation to theoretically test how the four galaxies in the core region formed and evolved. The results showed that a region of dense gas particles existed around 680 million years after the Big Bang, and shows that four galaxies are formed, similar to the observed core region. To follow the evolution of these four galaxies, the simulation calculated physical processes such as the kinematics of stars and gas, chemical reactions, star formation, and supernovae. The simulations showed that the four galaxies merge and evolve into a single larger galaxy within a few tens of millions of years, which is a short time scale in the evolution of the Universe. "We successfully reproduced the properties of the galaxies in the core region owing to the high spatial resolution of our simulations and the large number of galaxy samples we have. In the future, we would like to explore the formation mechanism of the core region and its dynamical properties in more detail," says Yurina Nakazato, a graduate student at the University of Tokyo, who analyzed the simulation data.

Javier Álvarez-Márquez (Spanish Center for Astrobiology) says, "We will conduct more sensitive observations of the proto-cluster A2744z7p9OD with ALMA to see if there are any galaxies that were not visible with the previous sensitivity. We will also apply the JWST and ALMA observations, which have proven to be very powerful, to more protoclusters to elucidate the growth mechanism of galaxies, and to explore our roots in the Universe."

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Glacier Loss Day indi­cates record break­ing glacier melt

In the summer of 2022, one of Tyrol's largest glaciers experienced its most significant loss of mass on record. Last year, the Hintereisferner in Tyrol, Austria, reached its Glacier Loss Day (GLD) earlier than ever before. The GLD serves as an indicator of a glacier's health throughout the year, similar to how the Earth Overshoot Day measures Earth's resource consumption. Annelies Voordendag, together with a team of glaciologists at the Department of Atmospheric and Cryospheric Sciences at the University of Innsbruck, employs cutting-edge laser scanning techniques to determine the GLD.

The Hintereisferner, located at the back of the Tyrolean Ötztal, has been closely monitored for more than 100 years, and there have been continuous records of its mass balance since 1952. This makes it one of the best-studied glaciers in the Alps and has been key to glacier and climate research at the University of Innsbruck for decades. Since 2016, the researchers have also been surveying the glacier with a worldwide unique system: the surface of the glacier is scanned daily with a terrestrial laser scanner returning the glacier surface elevation changes. This way, the change in the volume of the Hintereisferner is monitored in real time. Innsbruck glaciologist Annelies Voordendag led the measurement on site at the Hintereisferner, the results of the researchers' investigations have now been published as highlighted article in the journal The Cryosphere.

"Already in the early summer of 2022, it became clear that the day when the ice the glacier gained during the winter starts melting away would be reached very soon. We call this day the 'Glacier Loss Day' or GLD for short. It can be compared to the Earth Overshoot Day, which marks the date when we use up more natural resources than the Earth can renew in a year," explains Annelies Voordendag. Monitoring a glacier's volume and mass alterations on a daily basis provides a quick assessment of its condition in a given year.

Observing glaciers' health

When the GLD arrives, it means the glacier is no longer in balance with the natural conditions for that year. The earlier the GLD happens, the more time is left in the remaining summer that the glacier likely will lose volume and thus, mass. "We track the daily volume changes with the automated terrestrial laser scanninng setup overlooking the glacier and derive the day that the mass gained during winter has been lost," says Voordendag. In 2022 the GLD was measured on the 23rd of June. In the two previous years, Glacier Loss Day was reached only in the middle of August.

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Australian woman found with parasitic roundworm in her brain caught from carpet python

The world's first case of a new parasitic infection in humans has been discovered by researchers at The Australian National University (ANU) and the Canberra Hospital after they detected a live eight-centimetre roundworm from a carpet python in the brain of a 64- year-old Australian woman.

The Ophidascaris robertsi roundworm was pulled from the patient after brain surgery -- still alive and wriggling. It is suspected larvae, or juveniles, were also present in other organs in the woman's body, including the lungs and liver.

"This is the first-ever human case of Ophidascaris to be described in the world," leading ANU and Canberra Hospital infectious disease expert and co-author of the study Associate Professor Sanjaya Senanayake said.

"To our knowledge, this is also the first case to involve the brain of any mammalian species, human or otherwise.

"Normally the larvae from the roundworm are found in small mammals and marsupials, which are eaten by the python, allowing the life cycle to complete itself in the snake."

Ophidascaris robertsi roundworms are common to carpet pythons. It typically lives in a python's oesophagus and stomach, and sheds its eggs in the host's faeces. Humans infected with Ophidascaris robertsi larvae would be considered accidental hosts.

Roundworms are incredibly resilient and able to thrive in a wide range of environments. In humans, they can cause stomach pain, vomiting, diarrhoea, appetite and weight loss, fever and tiredness.

The researchers say the woman, from southeastern New South Wales in Australia, likely caught the roundworm after collecting a type of native grass, Warrigal greens, beside a lake near where she lived in which the python had shed the parasite via its faeces.

The patient used the Warrigal greens for cooking and was probably infected with the parasite directly from touching the native grass or after eating the greens.

Canberra Hospital's Director of Clinical Microbiology and Associate Professor at the ANU Medical School, Karina Kennedy, said her symptoms first started in January 2021.

"She initially developed abdominal pain and diarrhoea, followed by fever, cough and shortness of breath. In retrospect, these symptoms were likely due to migration of roundworm larvae from the bowel and into other organs, such as the liver and the lungs. Respiratory samples and a lung biopsy were performed; however, no parasites were identified in these specimens," she said.

"At that time, trying to identify the microscopic larvae, which had never previously been identified as causing human infection, was a bit like trying to find a needle in a haystack.

"In 2022, she began experiencing subtle changes in memory and thought processing and underwent a brain MRI scan which demonstrated an atypical lesion within the right frontal lobe of the brain."

The patient was first admitted to a local hospital in late January 2021 after suffering three weeks of abdominal pain and diarrhoea, followed by a constant dry cough, fever and night sweats. By 2022, the patient was experiencing forgetfulness and depression, prompting an MRI scan.

A neurosurgeon at Canberra Hospital explored the abnormality and it was then that the unexpected eight-centimetre roundworm was found. Its identity was later confirmed through parasitology experts, initially through its appearance and then through molecular studies.

Associate Professor Senanayake said the world-first case highlighted the danger of diseases and infections passing from animals to humans, especially as we start to live more closely together and our habitats overlap more and more.

"There have been about 30 new infections in the world in the last 30 years. Of the emerging infections globally, about 75 per cent are zoonotic, meaning there has been transmission from the animal world to the human world. This includes coronaviruses," he said.

"This Ophidascaris infection does not transmit between people, so it won't cause a pandemic like SARS, COVID-19 or Ebola. However, the snake and parasite are found in other parts of the world, so it is likely that other cases will be recognised in coming years in other countries."

Associate Professor Karina Kennedy said the important message from this case is about general food safety, particularly when gardening or foraging for food where there may be other wildlife in close proximity.

"People who garden or forage for food should wash their hands after gardening and touching foraged products. Any food used for salads or cooking should also be thoroughly washed, and kitchen surfaces and cutting boards, wiped downed and cleaned after use," she said.

The patient continues to be monitored by the team of infectious diseases and brain specialists.

"It is never easy or desirable to be the first patient in the world for anything. I can't state enough our admiration for this woman who has shown patience and courage through this process," Associate Professor Senanayake said.

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Archaeologists discover world's oldest wooden structure

Half a million years ago, earlier than was previously thought possible, humans were building structures made of wood, according to new research by a team from the University of Liverpool and Aberystwyth University.

The research, published in the journal Nature, reports on the excavation of well-preserved wood at the archaeological site of Kalambo Falls, Zambia, dating back at least 476,000 years and predating the evolution of our own species, Homo sapiens.

Expert analysis of stone tool cut-marks on the wood show that these early humans shaped and joined two large logs to make a structure, probably the foundation of a platform or part of a dwelling.

This is the earliest evidence from anywhere in the world of the deliberate crafting of logs to fit together. Until now, evidence for the human use of wood was limited to its use for making fire, digging sticks and spears.

Wood is rarely found in such ancient sites as it usually rots and disappears, but at Kalambo Falls permanently high water levels preserved the wood.

This discovery challenges the prevailing view that Stone Age humans were nomadic. At Kalambo Falls these humans not only had a perennial source of water, but the forest around them provided enough food to enable them to settle and make structures.

Professor Larry Barham, from the University of Liverpool's Department of Archaeology, Classics and Egyptology, who leads the 'Deep Roots of Humanity' research project said:

"This find has changed how I think about our early ancestors. Forget the label 'Stone Age,' look at what these people were doing: they made something new, and large, from wood. They used their intelligence, imagination, and skills to create something they'd never seen before, something that had never previously existed."

"They transformed their surroundings to make life easier, even if it was only by making a platform to sit on by the river to do their daily chores. These folks were more like us than we thought."

The specialist dating of the finds was undertaken by experts at Aberystwyth University.

They used new luminescence dating techniques, which reveal the last time minerals in the sand surrounding the finds were exposed to sunlight, to determine their age.

Professor Geoff Duller from Aberystwyth University said:

"At this great age, putting a date on finds is very challenging and we used luminescence dating to do this. These new dating methods have far reaching implications -- allowing us to date much further back in time, to piece together sites that give us a glimpse into human evolution. The site at Kalambo Falls had been excavated back in the 1960s when similar pieces of wood were recovered, but they were unable to date them, so the true significance of the site was unclear until now."

The site of Kalambo Falls on the Kalambo River lies above a 235 metres (772 foot) waterfall on the border of Zambia with the Rukwa Region of Tanzania at the edge of Lake Tanganyika. The area is on a 'tentative' list from UNESCO for becoming a World Heritage site because of its archaeological significance.

Professor Duller added:

"Our research proves that this site is much older than previously thought, so its archaeological significance is now even greater. It adds more weight to the argument that it should be a United Nations World Heritage Site."

This research forms part of the pioneering 'Deep Roots of Humanity' project, an investigation into how human technology developed in the Stone Age. The project is funded by the UK's Arts and Humanities Research Council and involved teams from Zambia's National Heritage Conservation Commission, Livingstone Museum, Moto Moto Museum and the National Museum, Lusaka.

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New clues to the nature of elusive dark matter

A team of international researchers, led by experts at the University of Adelaide, has uncovered further clues in the quest for insights into the nature of dark matter.

"Dark matter makes up 84 per cent of the matter in the universe but we know very little about it," said Professor Anthony Thomas, Elder Professor of Physics, University of Adelaide.

"The existence of dark matter has been firmly established from its gravitational interactions, yet its precise nature continues to elude us despite the best efforts of physicists around the world."

"The key to understanding this mystery could lie with the dark photon, a theoretical massive particle that may serve as a portal between the dark sector of particles and regular matter."

Regular matter, of which we and our physical world are made up of, is far less abundant than dark matter: five times more dark matter exists than regular matter. Finding out more about dark matter is one of the greatest challenges for physicists around the world.

The dark photon is a hypothetical hidden sector particle, proposed as a force carrier similar to the photon of electromagnetism but potentially connected to dark matter. Testing existing theories about dark matter is one of the approaches that scientists such as Professor Thomas, along with colleagues Professor Martin White, Dr Xuangong Wang and Nicholas Hunt-Smith, who are members of the Australian Research Council (ARC) Centre of Excellence for Dark Matter Particle Physics, are pursuing in order to gain more clues into this elusive but highly important substance.

"In our latest study, we examine the potential effects that a dark photon could have on the complete set of experimental results from the deep inelastic scattering process," said Professor Thomas.

Analysis of the by-products of the collisions of particles accelerated to extremely high energies gives scientists good evidence of the structure of the subatomic world and the laws of nature governing it.

In particle physics, deep inelastic scattering is the name given to a process used to probe the insides of hadrons (particularly the baryons, such as protons and neutrons), using electrons, muons and neutrinos.

"We have made use of the state-of-the-art Jefferson Lab Angular Momentum (JAM) parton distribution function global analysis framework, modifying the underlying theory to allow for the possibility of a dark photon," said Professor Thomas.

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Why do some environmental shocks lead to disaster while others don't?

It's no longer just about stopping, but how we can live with climate change. To figure this out, we must delve into our cultures, as highlighted in a special issue of The Royal Society. A study by the Complexity Science Hub points out how our history could help guide the way.

Currently, we are grappling with a global crisis convergence. Various types of threats intersect, intertwine, and test our collective resilience, from climate change and economic inequality to political polarization. Although the scale and global reach of these challenges present new hurdles, these threats have been faced and, sometimes, overcome in the past. Societies today barely have time to recover from one crisis to the next, but we possess a significant advantage: knowledge. The knowledge we can obtain from our history through new methods.

DATA FROM MORE THAN 15O CRISES

CSH researchers Peter Turchin and Daniel Hoyer have pioneered fresh approaches to drawing lessons from history. Together with colleagues from different fields, they have compiled the Crisis Database (CrisisDB) as part of the Global History Databank Seshat, containing over 150 past crises spanning different time periods and regions.

When earthquakes shook the earth, droughts parched the land, or floods ravaged regions, some societies succumbed to social unrest, civil violence, or total collapse, while others exhibited resilience, maintaining essential social functions or even achieving improvement through systemic reforms that promoted well-being and increased democratic participation. Daniel Hoyer remarks, "What we observe is that not every ecological shock or climatic anomaly leads to collapse or even a severe crisis, and not every crisis involves a major environmental stressor." But what makes the difference? What drives collapse versus positive change?

DIVERGENT EXPERIENCES IN DIFFERENT TIMES AND PLACES

To illustrate the divergent dynamics experienced by past societies, and to highlight the comprehensiveness of their data, the researchers provide three examples. The Zapotec hilltop settlement of Monte Albán in southern Mexico emerged as the most significant settlement in the region. Extreme, persistent drought hit the region in the 9th century, and the once-great site of Monte Albán was entirely abandoned along with many other cities in Mesoamerica. However, recent research presented here shows that this was hardly a case of 'societal collapse', as many former residents of Monte Albán resettled in smaller communities nearby, likely without massive mortality, but rather through an ideological and socio-economic reorientation that also preserved many aspects of their society.

On the opposite end of the spectrum, the immensely wealthy Qing Dynasty in China proved resilient to adverse ecological conditions -- recurrent floods, droughts, swarms of locusts -- during the early part of their reign, but by the 19th century, social pressures had built up leaving them more vulnerable to these same challenges. It was in this period that suffered the Taiping Rebellion, often seen as the bloodiest civil war in human history, and ultimately collapsed completely in 1912 after 250 years of rule. Learn more about the causes in a new study.

In between, the researchers highlight the Ottoman Empire, which faced daunting environmental conditions during the 16th century, including recurrent droughts and the Little Ice Age, leading to social unrest and numerous rebellions led by disgruntled local officials and wealthy families, yet they managed to maintain key social and political structures and avoided collapse, ruling a large swath of territory for several hundreds of years more.

GENERALIZABLE TO MULTIPLE CASES

"Many studies typically concentrate on a single event or a specific society. However, it is only by exploring the responses of all, or at least many, societies affected by a particular climate 'regime' that we can ascertain the causal influence and overall effectiveness of the environmental stressor," Peter Turchin says. With this objective in mind, the researchers have developed a methodological framework aimed at producing insights that can be applied to numerous cases across different regions and time periods, helping identify the underlying causes of divergent outcomes.

UNDERSTANDING THE DYNAMICS

"The course of a crisis hinges on numerous factors. Environmental forces are undeniably pivotal, but it's not as straightforward as a specific climate event triggering a predetermined societal response," asserts Turchin. Instead, these forces interact with cultural, political, and economic dynamics. Only by comprehending these dynamics can we fathom the interactions. Through their work on the CrisisDB program, the researchers and colleagues aim to unveil these patterns and pinpoint the key factors that either fortify or undermine resilience to contemporary climate shocks.

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Pearl Harbor: Bombed battleships' boost for climate science

Weather data from several ships bombed by Japanese pilots at Pearl Harbor has been recovered in a rescue mission that will help scientists understand how the global climate is changing.

Crew members aboard various vessels -- such as the USS Pennsylvania and the USS Tennessee -- died when their battleships were targeted in December 1941. Despite these losses, many boats returned to service during the Second World War and US naval servicemen continued their daily duties, which included recording weather data.

A new research paper, published in Geoscience Data Journal, tells the story of the recovery of World War II weather data that comes from 19 US Navy ships. Its rescue was made possible thanks to the hard work of over 4,000 volunteers who transcribed more than 28,000 logbook images from the US Navy fleet stationed at Hawai'i from 1941-1945. Previous studies have suggested these years were abnormally warm. The new dataset, encompassing over 630,000 records with more than 3 million individual observations, will help to show whether this was the case.

Dr Praveen Teleti, the University of Reading research scientist who led the research, said: "Disruptions to trade routes in World War II led to a significant reduction in marine weather observations. Until recently, records from that time were still only available in classified paper documents. The scanning and rescuing of this data provides a window into the past, allowing us to understand how the world's climate was behaving during a time of tremendous upheaval.

"There are two sets of people we need to thank for making this mission a success. We are very grateful to the global team of citizen scientists for transcribing these observations and creating a huge dataset that includes millions of entries about air and sea surface temperatures, atmospheric pressure, wind speed, and wind direction.

"The greatest respect must go to the brave servicemen who recorded this data. War was all around them, but they still did their jobs with such professionalism. It is thanks to their dedication and determination that we have these observations 80 years on."

Data from devastated ships

The logbooks used in the project come from 19 different ships, including battleships, aircraft carriers, destroyers, and cruisers, most of which played pivotal roles in World War II events. Many ships that data was recovered from were present at Pearl Harbor during the attack by Japanese bombers on 7 December 1941, although all ships listed in the study saw action in the Pacific at some point during the war. USS Pennsylvania was hit when Pearl Harbour was attacked by the Japanese air force in December 1941. One bomb fell on the battleship and caused the deaths of nine servicemen, but it remained in service. The USS Tennessee was bombed twice in December 1941, resulting in the death of five servicemen. It returned to service in February 1942.

Future climate studies

Observations from naval vessels were the primary sources of marine observations for the World War II period but many records were destroyed as an act of war, or simply forgotten due to the length of time they were considered classified.

The recovered dataset reveals how wartime necessitated changes in observation practices. For example, more observations were taken during daytime than nighttime to reduce exposure to the enemy ships and avoid being detected. It is believed that changes such as this could have led to slightly warmer temperatures being recorded, meaning today's history books show a period of abnormal warmth in global datasets during World War II. The new data will help resolve this uncertainty.

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Mature sperm lack intact mitochondrial DNA

New research provides insight about the bedrock scientific principle that mitochondrial DNA -- the distinct genetic code embedded in the organelle that serves as the powerplant of every cell in the body -- is exclusively passed down by the mother.

The study, a collaboration among Oregon Health & Science University and other institutions, published today in the journal Nature Genetics.

Scientists have long recognized the fact that mitochondrial DNA, or mtDNA, comes exclusively from egg cells in humans, meaning only the mother contributes the genetic code carried by thousands of mitochondria necessary for energy production in every cell in the body.

Previously, it was believed that paternal mtDNA was eliminated soon after a sperm fuses with an oocyte, or developing egg, during fertilization, possibly through an immune-like search-and-destroy response.

However, the study found that while mature sperm do carry a small number of mitochondria, they lack intact mtDNA.

"We found that each sperm cell does bring 100 or so mitochondria as organelles when it fertilizes an egg, but there is no mtDNA in them," said co-author Shoukhrat Mitalipov, Ph.D., director of the Center for Embryonic Cell and Gene Therapy at OHSU.

Researchers found that sperm cells are not only devoid of intact mtDNA, but they also lacked a protein essential for mtDNA maintenance, known as mitochondrial transcription factor A, or TFAM.

Scientists aren't sure why sperm are not allowed to contribute mtDNA, but Mitalipov theorizes that it may relate to the fact that a sperm uses a lot of mitochondrial energy in its biological impetus to fertilize an egg. It would thus accumulate mutations in mtDNA. The developing eggs known as oocytes, by contrast, draw energy primarily from surrounding cells, not from their own mitochondria, so maintain relatively pristine mtDNA.

"Eggs pass on really good mtDNA at least partly because they don't use mitochondria as a source of energy," Mitalipov said.

The 100 or so organelles in sperm are swamped by hundreds of thousands of mitochondria embedded in each egg cell -- each carrying the 37 genes in mitochondrial DNA. The contribution of only maternal mtDNA is believed to confer an evolutionary advantage by limiting the risk of accumulations of mtDNA mutations that cause disease in offspring.

Mitochondria control respiration and energy production within every cell of the body, so mutations in mtDNA can cause a range of potentially fatal disorders affecting organs with high-energy demands, such as the heart, muscle and brain.

To help mothers prevent passing on known mtDNA disorders to their children, Mitalipov pioneered a method called mitochondrial replacement therapy to replace mutant mtDNA through in vitro fertilization using healthy mtDNA from donor eggs.

Congress has prevented the Food and Drug Administration from overseeing clinical trials using the procedure in the U.S., so clinical trials are instead being conducted overseas, including clinical trials in the United Kingdom to prevent disease and in Greece to treat infertility.

Read more at Science Daily

New findings suggest Moon may have less water than previously thought

A team including Southwest Research Institute's Dr. Raluca Rufu recently calculated that most of the Moon's permanently shadowed regions (PSRs) are at most around 3.4 billion years old and can contain relatively young deposits of water ice. Water resources are considered key for sustainable exploration of the Moon and beyond, but these findings suggest that current estimates for cold-trapped ices are too high.

The current tilt of the Moon's spin axis combined with its orbital inclination -- the angle to Earth's orbital plane -- and the Sun's low angle creates permanent shadows at its poles. PSRs are some of the coldest spots in the solar system, allowing them to trap volatile chemicals, including water ice, that would immediately transform directly from a solid to a gas in the harsh, airless sunshine that falls in most other places on the Moon.

"We think the Earth-Moon system formed following a giant impact between early Earth and another protoplanet," said Rufu, a Sagan Fellow who is the second author of a Science Advances paper. "The Moon formed from the impact-generated debris disk, migrating away from Earth over time. Around 4.1 billion years ago the Moon experienced a major spin axis reorientation when its tilt reached high angles before it damped down to the configuration we see today. As the axial tilt decreased, PSRs appeared at the poles and grew over time."

The team used AstroGeo22, a new Earth-Moon evolution simulation tool, to calculate the Moon's axial tilt over time. Together with surface height measurements from the Lunar Orbital Altimeter Laser data (LOLA), the team estimated the evolution of the shadowed areas over time.

"The time evolution of the Moon-Earth distance remained an unsolved problem for half a century," Rufu said. "However, these new geological proxies for the history of the Earth-Moon system allow us to calculate the Moon's axial tilt and the extent of PSRs over time."

In 2009, NASA crashed the two-ton Atlas Centaur rocket body, part of the Lunar Crater Observation and Sensing Satellite (LCROSS), near the south pole of the Moon. It struck the floor of Cabeus crater, creating a plume of debris examined for the presence of water and other chemicals in the lunar regolith. A shepherding satellite travelling four minutes behind the Centaur and several Earth-orbiting satellites, including the Hubble Space Telescope, monitored the impact.

"Our work suggests that Cabeus crater became a PSR less than a billion years ago. The various volatiles detected in the plume created by LCROSS indicate that ice-trapping continued into relatively recent times," said Norbert Schörghofer, the lead author of this paper from the Planetary Science Institute. "Impacts and outgassing are potential sources of water but peaked early in lunar history, when the present-day PSRs did not yet exist. The age of PSRs largely determines the amount of water ice that could be trapped in the lunar polar regions. Information about the abundance of water ice in PSRs is particularly important in planning for upcoming crewed and uncrewed missions to the Moon searching for water."

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Brilliant galaxies of early universe

Rochester Institute of Technology scientists have once again used data from the James Webb Space Telescope (JWST) as part of the Cosmic Evolution Early Release Science (CEERS) Survey to change the way we think about the universe and its distant galaxies.

Jeyhan Kartaltepe, associate professor in the School of Physics and Astronomy, and Rebecca Larson, postdoctoral research associate, co-authored a paper, "Confirmation and refutation of very luminous galaxies in the early Universe," published in Nature confirming very bright galaxies in the early universe, while also disproving the identification of what would have been the most distant galaxy ever found.

Kartaltepe and Larson, along with co-authors from around the world, studied the redshift (or displacement of the spectrum of an object toward longer, red wavelengths) of several specific galaxies to see how much the light shifted, which indicates how far away the galaxies are. The CEERS team focused on Maisie's Galaxy, which was theorized to have a redshift of z ≈ 11.5, while a team in Scotland researched a nearby galaxy that they believed could have a redshift of z ≈ 16, far larger than any ever found before.

To examine further, the two teams partnered on a proposal to receive follow-up spectroscopy. When the new data came in, the teams were able to precisely measure the redshifts of both of these candidates, along with a few others.

"Spectra are how you really confirm what a galaxy's redshift is," explained Kartaltepe. "For these two galaxies, the answer was very clear -- the spectra look completely different. We confirmed that Maisie's Galaxy is at the high redshift we thought it was."

The group also found that because of a coincidence that mimicked the colors of a high redshift galaxy, the other galaxy is not at a redshift of z ≈ 16, but at a redshift of z ≈ 4.9. Both the initial and follow-up data from JWST turned the theories into discoveries.

"Not only did JWST find these galaxies we didn't know about before, but then it confirmed the redshift for them," said Larson. "This paper in particular speaks to the power of not only JWST finding galaxies in the really early universe but also confirming and characterizing them."

The research and the paper would not have been possible without dedicated collaboration between the CEERS team and the team in Scotland. Instead of working separately on their individual galaxies and submitting separate proposals, the partnership allowed for the follow-up spectroscopy to be accepted, and the subsequent analysis to be conducted efficiently, leading to new information about the universe.

When researching the data from JWST, scientists aim to find the highest redshift galaxies, or the most distant galaxies. Finding galaxies in the very early universe was one of the goals for the JWST. These and other early discoveries have proven the success of the telescope, even this early in its existence.

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Polar experiments reveal seasonal cycle in Antarctic sea ice algae

In the frigid waters surrounding Antarctica, an unusual seasonal cycle occurs. During winter, from March to October, the sun barely rises. As seawater freezes it rejects salts, creating pockets of extra-salty brine where microbes live in winter. In summer, the sea ice melts under constant daylight, producing warmer, fresher water at the surface.

This remote ecosystem is home to much of the Southern Ocean's photosynthetic life. A new University of Washington study provides the first measurements of how sea-ice algae and other single-celled life adjust to these seasonal rhythms, offering clues to what might happen as this environment shifts under climate change.

The study, published Sept. 15 in the International Society for Microbial Ecology's ISME Journal, contains some of the first measurements of how sea-ice microbes respond to changing conditions.

"We know very little about how sea-ice microbes respond to changes in salinity and temperature," said lead author Hannah Dawson, a UW postdoctoral researcher who did the work while pursuing her doctorate in oceanography at the UW. "And until now we knew almost nothing about the molecules they produce and use in chemical reactions to stay alive, which are important for supporting higher organisms in the ecosystem as well as for climate impacts, like carbon storage and cloud formation."

The polar oceans play an important role in global ocean currents and in supporting marine ecosystems. Microbes form the base of the food web, supporting larger life forms.

"Polar oceans make up a significant portion of the world's oceans, and these are very productive waters," said senior author Jodi Young, a UW assistant professor of oceanography. "These waters support big swarms of krill, the whales that come to feed on those krill, and either polar bears or penguins. And the start of that whole ecosystem are these single-celled microscopic algae. We just know so little about them."

The tiny organisms are also important for the climate, since they quietly perform photosynthesis and soak up carbon from the atmosphere. Polar algae are especially good at producing sulfur-containing molecules that give beaches their distinctive smell and, when lofted into the air in sea spray, promote formation of clouds that can reduce penetration of solar rays.

Antarctic sea ice, though long stable, is at an all-time record low this year.

In other oceans, satellite instruments can capture dramatic seasonal phytoplankton blooms from space -- but that isn't possible for microbes hidden under sea ice. And Antarctic waters are particularly challenging to visit, leaving researchers with almost no measurements in winter.

In late 2018, Dawson and co-author Susan Rundell traveled to Palmer Station, a U.S. research station on the West Antarctic Peninsula. They used a small boat to sample seawater and sea ice at the same nearby sites every three days.

Back on shore, the two graduate students performed 10-day experiments in tanks to see which microbes grew as temperature and salinity were adjusted to mimic sea-ice formation and melt. They also shipped samples back to Seattle for more complex measurements of the samples' genetics and metabolites, the small organic molecules produced by the cell.

Results revealed how single-celled algae deal with their fluctuating environments. As temperatures drop, the cells produce cryoprotectants, similar to antifreeze, to prevent their cellular fluid from crystallizing. Many of the most common cryoprotectant molecules were the same across different microbial lifeforms.

As salinity changes, to avoid either bursting in freshening waters or becoming desiccated like raisins in salty conditions, the cells change the concentration of salt-like organic molecules. Many such molecules serve a dual role as cryoprotectants, to balance conditions inside and outside the cell to maintain water balance.

The results show that under short-term temperature and salinity changes, community structure in each sample remained stable while adjusting the production of protective molecules. Different microbe species showed consistent responses to changing conditions. This should simplify modeling future responses to climate change, Young said.

Results also hint that the production of omega-3 fatty acids may decline in lower-salinity environments. This would be bad news for consumers of krill oil supplements, and for the marine ecosystem that relies on those algae-derived nutrients. Future research now underway by the UW group aims to confirm that result -- especially with the prospect of increasing freshwater input from melting sea ice and glaciers.

"We're interested in how these sea-ice algae contend with changes in temperature, salinity and light under normal conditions," Dawson said. "But then we also have climate change, which is completely remodeling the landscape in terms of when sea ice is forming, how much sea ice forms, how long it stays before it melts, as well as the quantity of freshwater input from glaciers. So we're both trying to capture what's happening now, and also asking how that can inform what might happen in the future."

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Brain-altering parasite turns ants into zombies at dawn and dusk

It takes over the brains of ants, causing them to cling to the tops of blades of grass where they can be eaten by cattle and deer. The common liver fluke has an exceptional life cycle as it moves through snails, ants and grass-grazing herbivores. And now, researchers from the University of Copenhagen know a bit more about the workings of this tiny parasite. The new knowledge adds to our understanding of parasites, which could be the most widespread life form on Earth.

Imagine coming-to, jaws gripping the top of a swaying blade of grass, unaware of how you got there. That's the reality for ants infected with the lancet liver fluke, a tiny parasitic flatworm. Liver flukes have a complicated, almost insanely conceived life cycle, which begins with the hijacking of the ant's brain. The unsuspecting ant climbs up and clamps its powerful jaws onto the top of a blade of grass, making it more likely to be eaten by grazers such as cattle and deer.

Researchers from the University of Copenhagen's Department of Plant and Environmental Sciences have discovered that the parasite's ability to control the ant is even more cunning than previously believed. Impressively, the parasite can even get the ant to crawl back down the blade of grass when it gets too hot.

"Getting the ants high up in the grass for when cattle or deer graze during the cool morning and evening hours, and then down again to avoid the sun's deadly rays, is quite smart. Our discovery reveals a parasite that is more sophisticated than we originally believed it to be," explains Associate Professor Brian Lund Fredensborg, who conducted the study together with former graduate student Simone Nordstrand Gasque, now a PhD student at Wageningen University in the Netherlands.

Zombie "on/off switch"

The researchers tagged several hundred infected ants in the Bidstrup Forests near Roskilde, Denmark.

"It took some dexterity to glue colors and numbers onto the rear segments of the ants, but it allowed us to keep track of them for longer periods of time," says Brian Lund Fredensborg.

They then observed the infected ants' behavior in relation to light, humidity, time of day and temperature. It was clear that temperature had an effect on ant behavior. When the temperature was low, the ants were more likely to be attached to the top of a blade of grass. When the temperature rose, the ants relinquished the grass and crawled back down.

"We found a clear correlation between temperature and ant behavior. We joked about having found the ants' zombie switch," says Brian Lund Fredensborg.

Trojan horse

Once the liver fluke infects the ant, several hundred parasites invade the ant's body. But only one makes its way to the brain, where it can influence the ant's behavior. The rest of the liver flukes conceal themselves in the ant's abdomen.

"Here, there can be hundreds of liver flukes waiting for the ant to get them into their next host. They are wrapped in a capsule which protects them from the consequent host's stomach acid, while the liver fluke that took control of the ant, dies. You could say that it sacrifices itself for the others," explains Brian Lund Fredensborg.

Animals infected with many liver flukes can suffer liver damage as the parasite moves around the host's liver and bile ducts.

Nature's biggest influencer

Brian Lund Fredensborg notes that there are many other examples of parasites that alter animal behavior. As such, parasites that hijack their host'sbehavior have a greater hand in the food chain than many might think. According to Fredensborg, this new study sheds light on an extremely underrated group of creatures.

"Historically, parasites have never really been focused on that much, despite there being scientific sources which say that parasitism is the most widespread life form. This is in part due to the fact that parasites are quite difficult to study. Nevertheless, the hidden world of parasites forms a significant part of biodiversity, and by changing the host's behavior, they can help determine who eats what in nature. That's why they're important for us to understand," he says.

The tiny liver fluke is widespread in Denmark, and other temperate regions worldwide. The researcher and his colleagues will continue to investigate the parasite, and excactly how it takes over an ant's brain.

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The universe caught suppressing cosmic structure growth

As the universe evolves, scientists expect large cosmic structures to grow at a certain rate: dense regions such as galaxy clusters would grow denser, while the void of space would grow emptier.

But University of Michigan researchers have discovered that the rate at which these large structures grow is slower than predicted by Einstein's Theory of General Relativity.

They also showed that as dark energy accelerates the universe's global expansion, the suppression of the cosmic structure growth that the researchers see in their data is even more prominent than what the theory predicts. Their results are published in Physical Review Letters.

Galaxies are threaded throughout our universe like a giant cosmic spider web. Their distribution is not random. Instead, they tend to cluster together. In fact, the whole cosmic web started out as tiny clumps of matter in the early universe, which gradually grew into individual galaxies, and eventually galaxy clusters and filaments.

"Throughout the cosmic time, an initially small clump of mass attracts and accumulates more and more matter from its local region through gravitational interaction. As the region becomes denser and denser, it eventually collapses under its own gravity," said Minh Nguyen, lead author of the study and postdoctoral research fellow in the U-M Department of Physics.

"So as they collapse, the clumps grow denser. That is what we mean by growth. It's like a fabric loom where one-, two- and three-dimensional collapses look like a sheet, a filament and a node. The reality is a mixture of all three cases, and you have galaxies living along the filaments while galaxy clusters -- groups of thousands of galaxies, the most massive objects in our universe bounded by gravity -- sit at the nodes."

The universe is not only made of matter. It also likely contains a mysterious component called dark energy. Dark energy accelerates the expansion of the universe on a global scale. As dark energy accelerates the expansion of the universe, it has the opposite effect on large structures.

"If gravity acts like an amplifier enhancing matter perturbations to grow into large-scale structure, then dark energy acts like an attenuator damping these perturbations and slowing the growth of structure," Nguyen said. "By examining how cosmic structure has been clustering and growing, we can try to understand the nature of gravity and dark energy."

Nguyen, U-M physics professor Dragan Huterer and U-M graduate student Yuewei Wen examined the temporal growth of large-scale structure throughout cosmic time using several cosmological probes.

First, the team used what's called the cosmic microwave background. The cosmic microwave background, or CMB, is composed of photons emitted just after the Big Bang. These photons provide a snapshot of the very early universe. As the photons travel to our telescopes, their path can become distorted, or gravitationally lensed, by large-scale structure along the way. Examining them, the researchers can infer how structure and matter between us and the cosmic microwave background are distributed.

Nguyen and colleagues took advantage of a similar phenomenon with weak gravitational lensing of galaxy shapes. Light from background galaxies is distorted through gravitational interactions with foreground matter and galaxies. The cosmologists then decode these distortions to determine how the intervening matter is distributed.

"Crucially, as the CMB and background galaxies are located at different distances from us and our telescopes, galaxy weak gravitational lensing typically probes matter distributions at a later time compared to what is probed by CMB weak gravitational lensing," Nguyen said.

To track the growth of structure to an even later time, the researchers further used motions of galaxies in the local universe. As galaxies fall into the gravity wells of the underlying cosmic structures, their motions directly track structure growth.

"The difference in these growth rates that we have potentially discovered becomes more prominent as we approach the present day," Nguyen said. "These different probes individually and collectively indicate a growth suppression. Either we are missing some systematic errors in each of these probes, or we are missing some new, late-time physics in our standard model."

The findings potentially address the so-called S8 tension in cosmology. S8 is a parameter that describes the growth of structure. The tension arises when scientists use two different methods to determine the value of S8, and they do not agree. The first method, using photons from the cosmic microwave background, indicates a higher S8 value than the value inferred from galaxy weak gravitational lensing and galaxy clustering measurements.

Neither of these probes measures the growth of structure today. Instead, they probe structure at earlier times, then extrapolate those measurements to present time, assuming the standard model. Cosmic microwave background probes structure in the early universe, while galaxy weak gravitational lensing and clustering probe structure in the late universe.

The researchers' findings of a late-time suppression of growth would bring the two S8 values into perfect agreement, according to Nguyen.

"We were surprised with the high statistical significance of the anomalous growth suppression," Huterer said. "Honestly, I feel like the universe is trying to tell us something. It is now the job of us cosmologists to interpret these findings.

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