New exoplanet discovery builds better understanding of planet formation

An international team of scientists have discovered an unusual Jupiter-sized planet orbiting a low-mass star called TOI-4860, located in the Corvus constellation.

The newly discovered gas giant, named TOI-4860 b, is an unusual planet for two reasons: stars of such low mass are not expected to host planets like Jupiter, and the planet appears to be particularly enriched by heavy elements.

The study, led by University of Birmingham astronomers, is published today (Friday 4th August) in a letter published within the Monthly Notices of the Royal Astronomical Society.

The planet was initially identified using NASA's Transiting Exoplanet Survey Satellite as a drop of brightness while transiting in front of its host star, but that data alone was insufficient to confirm that it was a planet.

The team used the SPECULOOS South Observatory, located in the Atacama Desert in Chile, to measure the planetary signal in several wavelengths and validated the planetary nature. The astronomers also observed the planet just before and after it disappeared behind its host star, noticing that there was no change in light, meaning the planet was not emitting any. Finally, the team collaborated with a Japanese group using the Subaru Telescope in Hawai'i. Together they measured the mass of the planet to fully confirm it.

Following this star and confirming its planet was the initiative of a group of PhD students within the SPECULOOS project.

George Dransfield, one of those PhD students, who recently submitted her thesis at the University of Birmingham, explains: "Under the canonical planet formation model, the less mass a star has, the less massive is the disc of material around that star.

"Since planets are created from that disc, high-mass planets like Jupiter, were widely expected not to form. However, we were curious about this and wanted to check planetary candidates to see if it was possible. TOI-4860 is our first confirmation and also the lowest mass star hosting such a high mass planet."

Amaury Triaud, Professor of Exoplanetology at the University of Birmingham, who led the study said: "I am ever thankful to the bright PhD students of our team for proposing to observe systems like TOI-4860. Their work has really paid off since planets like TOI-4860 are vital to deepening our understanding of planet formation.

"A hint of what might have happened is hidden in the planetary properties, which appear particularly enriched in heavy elements. We have detected something similar in the host star too, so it is likely that an abundance of heavy elements catalysed the planet formation process."

The new gas giant takes about 1.52 days to complete a full orbit around its host star, but because its host is a cold low mass star, the planet itself can be referred to as a 'Warm Jupiter'. This is a subclass of planet that holds particular interest for astronomers looking to build on their initial observations and learn more about how these kinds of planets are formed.

Mathilde Timmermans, another student of the SPECULOOS project, working at the University of Liege in Belgium concludes: "Thanks to its very short orbital period, and to the properties of its host star, the discovery of TOI-4860 b provides a brilliant opportunity to study the atmospheric properties of a warm Jupiter and learn more about how gas giants are formed."

Read more at Science Daily

Oldest known species of swimming jellyfish identified

Royal Ontario Museum (ROM) announces the oldest swimming jellyfish in the fossil record with the newly named Burgessomedusa phasmiformis. These findings are announced in the journal Proceedings of the Royal Society B.

Jellyfish belong to medusozoans, or animals producing medusae, and include today's box jellies, hydroids, stalked jellyfish and true jellyfish. Medusozoans are part of one of the oldest groups of animals to have existed, called Cnidaria, a group which also includes corals and sea anemones. Burgessomedusa unambiguously shows that large, swimming jellyfish with a typical saucer or bell-shaped body had already evolved more than 500 million years ago.

Burgessomedusa fossils are exceptionally well preserved at the Burgess Shale considering jellyfish are roughly 95% composed of water. ROM holds close to two hundred specimens from which remarkable details of internal anatomy and tentacles can be observed, with some specimens reaching more than 20 centimetres in length. These details enable classifying Burgessomedusa as amedusozoan. By comparison with modern jellyfish, Burgessomedusa would also have been capable of free-swimming and the presence of tentacles would have enabled capturing sizeable prey.

"Although jellyfish and their relatives are thought to be one of the earliest animal groups to have evolved, they have been remarkably hard to pin down in the Cambrian fossil record. This discovery leaves no doubt they were swimming about at that time," said co-author Joe Moysiuk, a Ph.D. candidate in Ecology & Evolutionary Biology at the University of Toronto, who is based at ROM.

This study, identifying Burgessomedusa, is based on fossil specimens discovered at the Burgess Shale and mostly found in the late 1980s and 1990s under former ROM Curator of Invertebrate Palaeontology Desmond Collins. They show that the Cambrian food chain was far more complex than previously thought, and that predation was not limited to large swimming arthropods like Anomalocaris (see field image showing Burgessomedusa and Anomalocaris preserved on the same rock surface).

"Finding such incredibly delicate animals preserved in rock layers on top of these mountains is such a wonderous discovery. Burgessomedusa adds to the complexity of Cambrian foodwebs, and like Anomalocaris which lived in the same environment, these jellyfish were efficient swimming predators," said co-author, Dr. Jean-Bernard Caron, ROM's Richard Ivey Curator of Invertebrate Palaeontology. "This adds yet another remarkable lineage of animals that the Burgess Shale has preserved chronicling the evolution of life on Earth."

Cnidarians have complex life cycles with one or two body forms, a vase-shaped body, called a polyp, and in medusozoans, a bell or saucer-shaped body, called a medusa or jellyfish, which can be free-swimming or not. While fossilized polyps are known in ca. 560-million-year-old rocks, the origin of the free-swimming medusa or jellyfish is not well understood. Fossils of any type of jellyfish are extremely rare. As a consequence, their evolutionary history is based on microscopic fossilized larval stages and the results of molecular studies from living species (modelling of divergence times of DNA sequences). Though some fossils of comb-jellies have also been found at the Burgess Shale and in other Cambrian deposits, and may superficially resemble medusozoan jellyfish from the phylum Cnidaria, comb-jellies are actually from a quite separate phylum of animals called Ctenophora. Previous reports of Cambrian swimming jellyfish are reinterpreted as ctenophores.

Read more at Science Daily

Scientists uncover a startling -- and exploitable -- coordination of gene expression in tumors

A Ludwig Cancer Research study has identified a pair of genes whose expression by a type of immune cell within tumors is predictive of outcomes for cancer patients and is linked to a vast network of gene expression programs, engaged by multiple cell types in the tumor microenvironment, that control human cancers.

Researchers led by Ludwig Lausanne's Mikaël Pittet report in the current issue of Science that patients with higher expression of the gene CXCL9 in their tumor-associated macrophages had far better clinical outcomes than those with higher expression of a gene named SPP1 by the immune cells. Macrophages expressing the former gene, they show, are invariably poised to attack cancer cells, while those expressing SPP1 are in a state supportive of tumor growth. Most intriguing, however, is the discovery that when the ratio of CXCL9 to SPP1 is high in the tumor microenvironment (TME), gene expression programs in other TME cells indicate a similarly anti-tumor slant; a low CS ratio, on the other hand, invariably accompanies pro-tumor gene expression signatures across the TME.

"We were very surprised to find that just this one parameter -- the ratio of two genes primarily expressed by macrophages -- could tell us so much else about the tumor," said Pittet. "This is true for multiple types of solid tumors. It means that, despite their enormous complexity, the microenvironments of tumors are governed by a clear set of rules. We have described one of them in this study."

With further validation in prospective clinical studies, Pittet noted, the CS ratio could be an easily measured molecular marker of likely patient prognosis and a useful tool for the management of therapy. Beyond that, the networks of linked gene expression signatures across cell types identified by the study expose several potential molecular targets for the development of drugs that might tip the TME into a state more susceptible to treatments like immunotherapy.

Noncancerous cells of the TME play a critical role in the growth and viability of tumors. These include fibroblasts, which churn out the molecular filler of tissues, endothelial cells that build blood vessels, epithelial cells that line body cavities and a menagerie of immune cell species that variously help or hinder tumor growth. The possibility of targeting these cells to treat cancers is tantalizing because, unlike malignant cells, they do not mutate rapidly and are thus unlikely to evolve resistance to therapies.

Pittet and his colleagues were interested in how much the TME varies between tumors. To find out, they conducted an unbiased analysis of 52 primary and metastatic tumors from 51 patients with head and neck cancers, examining how global gene expression captured in individual cells but statistically analyzed across tumors as a whole corresponded to patient outcomes.

This approach identified CXCL9 and SPP1 -- whose expression is mutually exclusive in individual macrophages -- as being tightly linked to prognosis, and this turned out to be true for other solid cancers as well. The expression of the two genes, Pittet and colleagues show, is also more categorically associated with the anti-tumor or pro-tumor "polarity" of macrophages than currently used markers.

Notably, the ratio of CXCL9 and SPP1 expression (termed CShi or CSlow) was broadly consistent with the state of other types of TME cells in head and neck tumors and with several phenomena associated with pro- and anti-tumor effects. CShi tumors, for example, tended to be infiltrated with B and T lymphocytes and dendritic cells, which all drive anti-tumor immunity. Further, other cell types in these tumors engaged signaling molecules and pathways that fuel inflammation or otherwise instigate immune responses.

CSlow tumors, meanwhile, bore gene expression signatures associated with cancer growth and progression, such as adaptations to oxygen starvation, the formation of new blood vessels and the induction of cellular transformations that propel cancer metastasis.

"Just by looking at the ratio of these two genes in macrophages, you can deduce the molecular activity of tumor cells, endothelial cells, fibroblasts -- you name it," said Pittet. "This startling coherence means that tumors are not a chaotic place, that all these cell states within the TME are coordinated. This information has the potential to be very useful for the development of precision medicine strategies for cancer therapy."

Pittet and his colleagues will next examine whether the gene expression networks identified in their study can be used to prospectively predict patient outcomes or gauge likely responses to various therapies. They will also be looking in more detail at other coordinated axes of gene expression in the TME, how they interact with the CS ratio and how each influences the other.

"The big question is, what are the best ways to interfere therapeutically with this network, with the goal being benefit to the patient?" said Pittet.

Read more at Science Daily

Gas streamers feed triple baby stars

New observations and simulations of three spiral arms of gas feeding material to three protostars forming in a trinary system have clarified the formation of multi-star systems.

Most stars with a mass similar to the Sun form in multi-star systems together with other stars. So an understanding of multi-star system formation is important to an overall theory of star formation. However, the complexity and lack of high-resolution, high-sensitivity data left astronomers uncertain about the formation scenario. In particular, recent observations of protostars often reported structures called "streamers" of gas flows toward the protostars, but it has been unclear how these streamers form.

An international team led by Jeong-Eun Lee, a professor at Seoul National University, used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the trinary protostar system IRAS 04239+2436 located 460 light-years away in the constellation Taurus.

The team found that emissions from sulfur monoxide (SO) molecules trace three spiral arms around the three protostars forming in the system.

Comparison with simulations led by Tomoaki Matsumoto, a professor at Hosei University using the supercomputers "ATERUI" and "ATERUI II" in the Center for Computational Astrophysics at the National Astronomical Observatory of Japan (NAOJ) indicate that the three spiral arms are streamers feeding material to the three protostars. The combination of observations and simulations revealed, for the first time, how the streamers are created and contribute to the growth of the protostars at the center.

Read more at Science Daily

Exploring the origins of life

Catalytic molecules can form metabolically active clusters by creating and following concentration gradients -- this is the result of a new study by scientists from the Max Planck Institute for Dynamics and Self-Organization (MPI-DS). Their model predicts the self-organization of molecules involved in metabolic pathways, adding a possible new mechanism to the theory of the origin of life. The results can help to better understand how molecules participating in complex biological networks can form dynamic functional structures, and provide a platform for experiments on the origins of life.

One possible scenario for the origin of life is the spontaneous organization of interacting molecules into cell-like droplets. These molecular species would form the first self-replicating metabolic cycles, which are ubiquitous in biology and common throughout all organisms. According to this paradigm, the first biomolecules would need to cluster together through slow and overall inefficient processes. Such slow cluster formation seems incompatible with how quickly life has appeared. Scientists from the department of Living Matter Physics from MPI-DS have now proposed an alternative model that explains such cluster formation and thus the fast onset of the chemical reactions required to form life.

"For this, we considered different molecules, in a simple metabolic cycle, where each species produces a chemical used by the next one," says Vincent Ouazan-Reboul, the first author of the study. "The only elements in the model are the catalytic activity of the molecules, their ability to follow concentration gradients of the chemicals they produce and consume, as well as the information on the order of molecules in the cycle," he continues. Consequently, the model showed the formation of catalytic clusters including various molecular species. Furthermore, the growth of clusters happens exponentially fast. Molecules hence can assemble very quickly and in large numbers into dynamic structures.

"In addition, the number of molecule species which participate in the metabolic cycle plays a key role in the structure of the formed clusters," Ramin Golestanian, director at MPI-DS, summarizes: "Our model leads to a plethora of complex scenarios for self-organization and makes specific predictions about functional advantages that arise for odd or even number of participating species. It is remarkable that non-reciprocal interactions as required for our newly proposed scenario are generically present in all metabolic cycles."

In another study, the authors found that self-attraction is not required for clustering in a small metabolic network. Instead, network effects can cause even self-repelling catalysts to aggregate. With this, the researchers demonstrate new conditions in which complex interactions can create self-organized structures.

Read more at Science Daily

Hartshorn salt and 'baking' solves a serious environmental problem

Polyester is the second most used textile in the world and an environmental menace, especially because most of it never gets recycled. The fabric, a blend of plastic and cotton, has been difficult for the industry to separate and therefore recycle. Now, a group of young chemists from the University of Copenhagen has invented a green and surprisingly simple solution using a single household ingredient.

From clothes to sofas to curtains, polyester dominates our everyday lives, with a staggering 60 million tons of this popular fabric produced annually. However, polyester production takes a toll on the climate and the environment, as only a mere 15% of it is recycled, while the rest ends up in landfills or incinerated, being responsible of more carbon emission.

Recycling polyester poses a significant challenge, particularly in separating the plastic and cotton fibers that the blend fabric is made of without losing either of them in the process. Conventional recycling methods often prioritize preserving the plastic component, resulting in a loss of cotton fibers. Moreover, these methods are costly, complex, and generate metal waste due to the use of metal catalysts, which can be cytotoxic and contaminate the process.

In a remarkable breakthrough, a group of young chemists has unveiled a surprisingly simple solution to this pressing problem, potentially revolutionizing the sustainability of the textile industry.

"The textile industry urgently requires a better solution to handle blended fabrics like polyester/cotton. Currently, there are very few practical methods capable of recycling both cotton and plastic -- it's typically an either-or scenario. However, with our newly discovered technique, we can depolymerize polyester into its monomers while simultaneously recovering cotton on a scale of hundreds of grams, using an incredibly straightforward and environmentally friendly approach. This traceless catalytic methodology could be the game-changer," explains postdoc Yang Yang of the Jiwoong Lee group at the University of Copenhagen's Department of Chemistry, who serves as the lead author of the scientific research article.

Hartshorn salt and 24 hours in the 'oven'

The new method requires no special equipment -- just heat, a non-toxic solvent, and an ordinary household ingredient.

"For example, we can take a polyester dress, cut it up into small pieces and place it in a container. Then, add a bit of mild solvent, and thereafter hartshorn salt, which many people know as a leavening agent in baked goods. We then heat it all up to 160 degrees Celsius and leave it for 24 hours. The result is a liquid in which the plastic and cotton fibers settle into distinct layers. It's a simple and cost-effective process," explains Shriaya Sharma, a doctoral student of the Jiwoong Lee group at the Department of Chemistry and study co-author.

In the process, the hartshorn salt, also called ammonium bicarbonate, is broken down into ammonia, CO2 and water. The combination of ammonia and CO2 acts as a catalyst, triggering a selective depolymerization reaction that breaks down the polyester while preserving the cotton fibers. Although ammonia is toxic in isolation, when combined with CO2, it becomes both environmentally friendly and safe for use. Due to the mild nature of the chemicals involved, the cotton fibers remain intact and in excellent condition.

Previously, the same research group demonstrated that CO2 could serve as a catalyst for breaking down nylon, among other things, without leaving any trace. This discovery inspired them to explore the use of hartshorn salt. Nevertheless, the researchers were pleasantly surprised when their simple recipe yielded successful results.

"At first, we were excited to see it work so well on the PET bottles alone. Then, when we discovered that it worked on polyester fabric as well, we were just ecstatic. It was indescribable. That it was so simple to perform was nearly too good to be true," says Carlo Di Bernardo, doctoral student and study co-author.

While the method has only been tested at the laboratory level thus far, the researchers point to its scalability and are now in contact with companies to test the method on an industrial scale.

"We're hoping to commercialize this technology that harbors such great potential. Keeping this knowledge behind the walls of the university would be a huge waste," concludes Yang Yang.

Read more at Science Daily

Humans unable to detect over a quarter of deepfake speech samples

The study, published today in PLOS ONE, is the first to assess human ability to detect artificially generated speech in a language other than English.

Deepfakes are synthetic media intended to resemble a real person's voice or appearance. They fall under the category of generative artificial intelligence (AI), a type of machine learning (ML) that trains an algorithm to learn the patterns and characteristics of a dataset, such as video or audio of a real person, so that it can reproduce original sound or imagery.

While early deepfake speech algorithms may have required thousands of samples of a person's voice to be able to generate original audio, the latest pre-trained algorithms can recreate a person's voice using just a three-second clip of them speaking. Open-source algorithms are freely available and while some expertise would be beneficial, it would be feasible for an individual to train them within a few days.

Tech firm Apple recently announced software for iPhone and iPad that allows a user to create a copy of their voice using 15 minutes of recordings.

Researchers at UCL used a text-to-speech (TTS) algorithm trained on two publicly available datasets, one in English and one in Mandarin, to generate 50 deepfake speech samples in each language. These samples were different from the ones used to train the algorithm to avoid the possibility of it reproducing the original input.

These artificially generated samples and genuine samples were played for 529 participants to see whether they could detect the real thing from fake speech. Participants were only able to identify fake speech 73% of the time, which improved only slightly after they received training to recognise aspects of deepfake speech.

Kimberly Mai (UCL Computer Science), first author of the study, said: "Our findings confirm that humans are unable to reliably detect deepfake speech, whether or not they have received training to help them spot artificial content. It's also worth noting that the samples that we used in this study were created with algorithms that are relatively old, which raises the question whether humans would be less able to detect deepfake speech created using the most sophisticated technology available now and in the future."

The next step for the researchers is to develop better automated speech detectors as part of ongoing efforts to create detection capabilities to counter the threat of artificially generated audio and imagery.

Though there are benefits from generative AI audio technology, such as greater accessibility for those whose speech may be limited or who may lose their voice due to illness, there are growing fears that such technology could be used by criminals and nation states to cause significant harm to individuals and societies.

Documented cases of deepfake speech being used by criminals include one 2019 incident where the CEO of a British energy company was convinced to transfer hundreds of thousands of pounds to a false supplier by a deepfake recording of his boss's voice.

Read more at Science Daily

Gravitational arcs in 'El Gordo' galaxy cluster

A new image of the galaxy cluster known as "El Gordo" is revealing distant and dusty objects never seen before, and providing a bounty of fresh science. The infrared image, taken by NASA's James Webb Space Telescope, displays a variety of unusual, distorted background galaxies that were only hinted at in previous Hubble Space Telescope images.

El Gordo is a cluster of hundreds of galaxies that existed when the universe was 6.2 billion years old, making it a "cosmic teenager." It's the most massive cluster known to exist at that time. ("El Gordo" is Spanish for the "Fat One.")

The team targeted El Gordo because it acts as a natural, cosmic magnifying glass through a phenomenon known as gravitational lensing. Its powerful gravity bends and distorts the light of objects lying behind it, much like an eyeglass lens.

"Lensing by El Gordo boosts the brightness and magnifies the sizes of distant galaxies. This lensing effect provides a unique window into the distant universe," said Brenda Frye of the University of Arizona. Frye is co-lead of the PEARLS-Clusters branch of the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) team and lead author of one of four papers analyzing the El Gordo observations.

The Fishhook

Within the image of El Gordo, one of the most striking features is a bright arc represented in red at upper right. Nicknamed "El Anzuelo" (The Fishhook) by one of Frye's students, the light from this galaxy took 10.6 billion years to reach Earth. Its distinctive red color is due to a combination of reddening from dust within the galaxy itself and cosmological redshift due to its extreme distance.

By correcting for the distortions created by lensing, the team was able to determine that the background galaxy is disk-shaped but only 26,000 light-years in diameter -- about one-fourth the size of the Milky Way. They also were able to study the galaxy's star formation history, finding that star formation was already rapidly declining in the galaxy's center, a process known as quenching.

"We were able to carefully dissect the shroud of dust that envelops the galaxy center where stars are actively forming," said Patrick Kamieneski of Arizona State University, lead author on a second paper. "Now, with Webb, we can peer through this thick curtain of dust with ease, allowing us to see firsthand the assembly of galaxies from the inside out."

The Thin One

Another prominent feature in the Webb image is a long, pencil-thin line at left of center. Known as "La Flaca" (the Thin One), it is another lensed background galaxy whose light also took nearly 11 billion years to reach Earth.

Not far from La Flaca is another lensed galaxy. When the researchers examined that galaxy closely, they found a single red giant star that they nicknamed Quyllur, which is the Quechua term for star.

Previously, Hubble has found other lensed stars (such as Earendel), but they were all blue supergiants. Quyllur is the first individual red giant star observed beyond 1 billion light-years from Earth. Such stars at high redshift are only detectable using the infrared filters and sensitivity of Webb.

"It's almost impossible to see lensed red giant stars unless you go into the infrared. This is the first one we've found with Webb, but we expect there will be many more to come," said Jose Diego of the Instituto de Física de Cantabria in Spain, lead author of a third paper on El Gordo.

Galaxy Group and Smudges

Other objects within the Webb image, while less prominent, are equally interesting scientifically. For example, Frye and her team (which includes nine students from high school to graduate students) identified five multiply lensed galaxies which appear to be a baby galaxy cluster forming about 12.1 billion years ago. There are another dozen candidate galaxies which may also be part of this distant cluster.

"While additional data are required to confirm that there are 17 members of this cluster, we may be witnessing a new galaxy cluster forming right before our eyes, just over a billion years after the big bang," said Frye.

A final paper examines very faint, smudge-like galaxies known as ultra-diffuse galaxies. As their name suggests, these objects, which are scattered throughout the El Gordo cluster, have their stars widely spread out across space. The team identified some of the most distant ultra-diffuse galaxies ever observed, whose light traveled 7.2 billion years to reach us.

"We examined whether the properties of these galaxies are any different than the ultra-diffuse galaxies we see in the local universe, and we do actually see some differences. In particular, they are bluer, younger, more extended, and more evenly distributed throughout the cluster. This suggests that living in the cluster environment for the past 6 billion years has had a significant effect on these galaxies," explained Timothy Carleton of Arizona State University, lead author on the fourth paper.

Read more at Science Daily

Winter storms over Labrador Sea influence Gulf Stream system

The Gulf Stream, which brings warm water from the Gulf of Mexico to Europe and keeps the climate mild, is only part of a larger system of oceanic currents called the Atlantic Meridional Overturning Circulation, or AMOC for short. It runs through the Atlantic like a giant climate machine: as warm water from the tropics is transported northwards at the surface, the current reverses in the North Atlantic -- the water cools, becomes heavier and flows south at depth.

Where exactly these sinking processes take place is the subject of current research, and recent measurement programmes have located them to the east of Greenland. A team of scientists from the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, has now conducted a modelling study focusing on the Labrador Sea southwest of Greenland. In their study, now published in the journal Nature Communications, the researchers used complex computer simulations to show that fluctuations in the Labrador Sea can have a significant influence on the strength of sinking processes east of Greenland. An important link is a little-noticed system of deep currents that ensures rapid spreading of Labrador Sea water into the deep-sea basin between Greenland and Iceland.

"We oceanographers have long had our eyes on the Labrador Sea between Canada and Greenland," says Professor Dr Claus Böning, who led the study. "Winter storms with icy air cool the ocean temperatures to such an extent that the surface water becomes heavier than the water below. The result is deep winter mixing of the water column, whereby the volume and density of the resulting water mass can vary greatly from year to year."

In the model simulations of the past 60 years, the years 1990 to 1994 stood out, when the Labrador Sea cooled particularly strongly. "The unusually large volume of very dense Labrador Sea water that formed following extremely harsh winters led to significantly increased sinking between Greenland and Iceland in the following years," explains Claus Böning. As a result, the model simulations calculated an increase in Atlantic overturning transport of more than 20%, peaking in the late 1990s. The measurements of the circulation in the North Atlantic, which have only been carried out continuously since 2004, would then fall exactly in the decay phase of the simulated transport maximum.

"According to our model results, the observed weakening of the Atlantic circulation during this period can therefore be interpreted, at least in part, as an aftereffect of the extreme Labrador Sea winters of the 1990s," summarises Professor Dr Arne Biastoch, head of the Ocean Dynamics Research Unit at GEOMAR and co-author of the study. However, he clarifies: "Although we cannot yet say whether a longer-term weakening of the overturning is already occurring, all climate models predict a weakening as a result of human-induced climate change as 'very likely' for the future.

Read more at Science Daily

Butterfly-inspired films create vibrant colors while passively cooling objects

On a hot summer day, white clothing feels cooler than other colors due to reflecting -- not absorbing -- sunlight. Other colors like blue or black, will undergo a heating effect as they absorb light. To circumvent this heating effect in colored cooling films, researchers drew inspiration from nanostructures in butterfly wings.

The new films, which don't absorb any light, could be used on the outside of buildings, vehicles and equipment to reduce the energy needed for cooling while preserving vivid color properties.

"In buildings, large amounts of energy are used for cooling and ventilation, and running the air conditioner in electric cars can reduce the driving range by more than half," said research team leader Wanlin Wang from Shenzhen University in China. "Our cooling films could help advance energy sustainability and carbon neutrality."

In Optica, Optica Publishing Group's journal for high-impact research, the researchers show that the films they developed lower the temperature of colorful objects to about 2 °C below the ambient temperature. They also found that when left outside all day, the blue version of the films was approximately 26°C cooler than traditional blue car paint. This represents an annual energy savings of approximately 1377 MJ/m2 per year.

"With our new films, excellent cooling performance can be achieved, no matter the desired color, saturation or brightness," said Wang. "They could even be used on textiles to create clothes of any color that are comfortable in hot temperatures."

Inspired by nature

A car with blue paint appears blue because it absorbs yellow light and reflects blue light. The large amount of light that is absorbed heats the car. Morpho butterflies, however, produce their highly saturated blue color based on the nanostructure of their wings. The design of the cooling nanofilm mimics these structures to produce vibrant colors that don't absorb light like traditional paint.

To create their Morpho-inspired nanofilms, the researchers placed a disordered material (rough frosted glass) under a multilayer material made of titanium dioxide and aluminum dioxide. They then placed this structure on a silver layer that reflects all light, thus preventing the absorption of solar radiation and the heating associated with that absorption.

The film's color is determined by how components within its multilayered structure reflect light. To create blue, for example, the multilayer material is designed to reflect yellow light in a very narrow range of angles while the disordered structure diffuses the blue light across a broad area.

Although this type of passive photonic thermal management has been accomplished before, it has only been used with white or clear objects because it is difficult to maintain a wide viewing angle and high color saturation.

Passive cooling of colorful objects

"Thanks to the layered structure we developed, we were able to extend the passive cooling method from colorless objects to colorful ones while preserving color performance," said Wang. "In other words, our blue film looks blue across a large range of viewing angles and doesn't heat up because it reflects all the light. In addition, high saturation and brightness can be achieved by optimizing the structure."

To test the new technology, the researchers created blue, yellow and colorless films, which they placed outdoors at Shenzhen University, on surfaces such as roofs, cars, cloth and cell phones, from 9 a.m. to 4 p.m. in both winter and summer. Using thermocouple sensors and infrared cameras to measure temperature, they found that the cooling films were more than about 15 ? cooler than the surfaces they were placed on in the winter and about 35 ? cooler in the summer.

Read more at Science Daily