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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