Autistic children showed earlier and less age-related refinement in the brain signals involved in processing faces. A child looks at a face, and within milliseconds the brain begins sorting its features, expression, and identity. Researchers have now traced that process across the entire scalp in one of the most comprehensive studies of face perception in [...]
Read more of this story at Slashdot.
A native Australian millet may carry the genetic fingerprints of thousands of years of Aboriginal harvesting, storage, and plant management. Seen from the air, Channel Country resembles a vibrant and vast tapestry, with a network of waterways crisscrossing the land. Spread across more than 280,000 square kilometers in outback Australia, it is one of the [...]
For years, ruthenium dioxide (RuO₂) has kept physicists confused. Depending on which experiment they looked at, the metallic oxide either appeared magnetic or not magnetic at all.
This uncertainty has made it difficult to determine whether RuO₂ belongs to an unusual new class of materials known as altermagnets, which could one day power faster and more energy-efficient electronics.
Now, in a new study, researchers have shown that the missing piece may not be the material itself—but how tightly it is stretched. By growing an ultrathin RuO₂ film just two nanometers thick and keeping its crystal lattice under strain, they detected clear signs of magnetic order that had remained hidden in thicker, relaxed samples.
The findings suggest that magnetism in RuO₂ is not a fixed property but something scientists may be able to switch on simply by engineering the material’s atomic structure. “RuO2 has attracted renewed interest due to expectations of prominent altermagnetic spin splitting,” the researchers said.
RuO₂ is already widely used as an industrial catalyst and is valued for its excellent electrical conductivity.
However, over the past few years, it has become the focus of an intense debate because some experiments suggested it might be an altermagnet—a recently proposed type of magnetic material that combines features of conventional magnets and nonmagnetic materials.
Unlike an ordinary bar magnet, an altermagnet has almost no overall magnetization even though its electrons remain magnetically ordered. Previous studies, however, produced conflicting results.
Some reported magnetic order, unusual Hall effects, and efficient spin-charge conversion, while others found no evidence of magnetism in bulk crystals or relaxed thin films. A recent study even concluded that RuO₂ showed no altermagnetic behavior down to films 5 nanometers thick.
However, no one had directly examined fully strained films thinner than about four nanometers using techniques capable of measuring both the motion and spin of electrons at the same time.
“The spin structure of RuO2 remains largely unexplored in the ultrathin limit,” the study authors note.
To explore that missing regime, the researchers grew atomically smooth RuO₂ films only two nanometers thick on titanium dioxide-based substrates. Since the substrate’s atomic spacing differs slightly from that of RuO₂, the ultrathin film is forced to stretch to match it—a condition known as epitaxial strain.
You can think of it like laying a small wire mesh over a frame with slightly different spacing. The mesh has to stretch to fit, subtly changing the positions of every junction. In a crystal, those tiny shifts alter how electrons move and interact.
The team then used spin-resolved angle-resolved photoemission spectroscopy (spin-ARPES), which shines light on the material to eject electrons. By measuring each electron’s energy, momentum, and spin, scientists can map the material’s electronic structure in remarkable detail.
To ensure the results were genuine, they repeated the measurements in two different experimental geometries to separate real magnetic signals from possible measurement artifacts. Additional X-ray and optical experiments confirmed that the films remained fully strained and revealed their crystal symmetry.
The measurements uncovered an unusual momentum-dependent spin texture, meaning the direction of an electron’s spin changed systematically depending on how it moved through the crystal.
After performing a detailed symmetry analysis, the researchers ruled out nonmagnetic explanations, including effects caused by the crystal’s polar structure or by the measurement process itself.
As the study authors note, “A comprehensive symmetry analysis rules out nonmagnetic origins of this spin texture. These findings suggest an emergent nonrelativistic spin structure enabled by epitaxial strain in the ultrathin limit, marking a distinct departure from the behavior of relaxed or bulk RuO₂.”
The observed behavior was consistent with either weak ferromagnetism or altermagnetism, indicating that strain fundamentally changes the electronic ground state of RuO₂.
The findings suggest that strain could become a practical way to switch magnetic properties on in materials that normally do not display them, opening new possibilities for low-power spintronic devices based on electron spin instead of electric charge.
However, the experiments were carried out at around 15 kelvin (about −258°C), so it is still unknown whether the same behavior persists at room temperature.
Future studies will need to determine exactly which magnetic state emerges and whether it can be reliably controlled in real-world devices.
The study is published in the journal Science Advances.
A 1.4-million-year-old trail of footprints reveals that a powerful human relative grew nearly as large as us and may have traveled in all-male groups. Eight individuals walked across the wet ground beside an ancient Kenyan lake. Within a short time, sediment buried their footprints and preserved a scene that would remain hidden for roughly 1.4 [...]From perfumes and synthetic flavorings to plastics and resins, acetaldehyde is a chemical used to make countless everyday products.
However, producing it efficiently has remained a challenge because the catalysts that convert ethanol into acetaldehyde gradually lose activity, generate unwanted byproducts, or break down over time.
Now, researchers have developed a three-metal catalyst that tackles those long-standing problems in an unusual way. By pairing platinum and chromium atoms inside a silver matrix, they created tiny dumbbell structures known as heterometallic pair sites.
These atomic pairs selectively remove only the hydrogen atoms needed to convert ethanol into acetaldehyde while suppressing the deactivation pathways seen in comparable platinum-silver and chromium-silver catalysts.
“Our catalyst solves an important problem in chemistry because it completes a selective dehydrogenation: Instead of stripping away all of the hydrogen atoms, it removes just the ones necessary,” Anatoly Frenkel, one of the study authors and a chemist at Stony Brook University, said.
Moreover, since the process starts with ethanol that can be produced from biomass such as crop residues, forestry waste, and food waste, it could also provide a more sustainable alternative to conventional petrochemical production.
Catalysts speed up chemical reactions without being consumed, but making one that is both fast and selective is difficult. In ethanol dehydrogenation, conventional catalysts often keep reacting after removing the required hydrogen atoms, triggering unwanted reactions.
Over time, they can also become coated with carbon deposits, known as coking, or undergo structural changes that reduce their performance.
To overcome these problems, the researchers turned to quantum mechanical calculations, which predicted that platinum and chromium atoms would naturally pair up when dispersed inside silver.
“Prior quantum chemical calculations and surface science experiments by our collaborators showed that platinum-chromium pairs form preferentially in silver and exhibit electronic structures distinct from isolated platinum and chromium sites, enabling unique surface chemistry,” Jason Weaver, one of the study authors and a chemist at the University of Florida, said.
The team then fabricated thin films of the alloys to test whether these predicted atomic pairs actually formed.
The researchers combined several advanced techniques to examine the catalyst from the inside out. At Brookhaven National Laboratory’s National Synchrotron Light Source II, X-ray absorption fine structure (XAFS) measurements confirmed that platinum and chromium atoms had indeed paired together throughout the silver host.
The catalyst’s surface was then analyzed at Sweden’s MAX IV synchrotron using surface-sensitive XAFS and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), which allowed scientists to observe the catalyst while it was actively converting ethanol.
These measurements showed that only catalysts containing platinum-chromium pairs efficiently produced acetaldehyde.
Additional scanning transmission electron microscopy (STEM) mapped the distribution of platinum and chromium atoms inside the silver matrix, providing further evidence that the unusual atomic arrangement was responsible for the catalyst’s behavior.
“Combining this with the local bonding information from surface-sensitive XAFS gives a really complete picture of the state of the catalyst and how this affects its performance,” Lindsay Merte, one of the study authors and an associate professor of physics at Malmö University, said.
Catalytic tests showed that the trimetallic platinum-chromium-silver catalyst became active at around 200°C and steadily increased its activity up to 350°C, where it selectively converted ethanol into acetaldehyde and hydrogen, with mass spectrometry identifying these as the dominant gaseous products.
In contrast, platinum-silver catalysts accumulated carbon deposits that blocked active sites, while chromium-silver catalysts became less effective because of oxidation.
The platinum-chromium pairs greatly suppressed both of these deactivation pathways, allowing the catalyst to remain active for longer.
The researchers also found that these heterometallic pair sites stayed stable even at relatively high active-metal loadings, addressing a common limitation of many atomically dispersed catalysts.
Previous studies had suggested that carefully designed pairs of different metals could outperform isolated single atoms, but this work provides experimental evidence that such heterometallic pair sites can operate under realistic reaction conditions.
The study offers a new blueprint for catalyst design. Instead of searching for entirely new materials, scientists may be able to create longer-lasting, more selective catalysts simply by arranging familiar metals in new atomic partnerships—a strategy that could benefit not only ethanol dehydrogenation but many other industrial chemical reactions as well.
However, the catalyst has so far been demonstrated only as a model thin-film system, so additional work will be needed before it can be adapted for industrial reactors.
The researchers’ next goal is to translate the same atomic design into high-surface-area nanoparticles, which are better suited for large-scale chemical manufacturing.
The study is published in the journal Angewandte Chemie.
Growing populations and expanding industries are intensifying freshwater shortages across parts of Africa, the Middle East, and Southeast Asia, increasing the need for sustainable water supplies. Solar desalination has emerged as a promising solution, using sunlight to convert seawater into freshwater with relatively low energy requirements.
But real-world conditions pose a challenge. Seawater near ports, shipping routes, and industrial areas is often contaminated with oil, which can clog desalination membranes and reduce their performance.
Although many experimental solar desalination systems have shown strong results in laboratory tests using clean saltwater, it remains uncertain how effectively they would operate in polluted seawater.
In an effort to overcome this limitation, researchers at Pusan National University developed a multifunctional hydrogel membrane that combines oil separation and solar-driven desalination in a single system.
Led by Professor Sanghyun Jeong from the Department of Civil and Environmental Engineering, the team designed a membrane architecture that simultaneously removes oil contaminants while producing freshwater, eliminating the need for separate treatment stages. The study was published online on June 1, 2026, and will appear in the October 15, 2026, issue of Desalination.
Inspired by the need for selective water treatment, the researchers developed a membrane with a “Janus” architecture, giving each side a distinct function. One surface is hydrophilic, made from a chitosan and polyvinyl alcohol hydrogel, allowing water to pass through while blocking oil droplets.
The opposite surface is hydrophobic and incorporates copper oxide nanoparticles coated with a carbon shell, which are embedded within a nanofiber layer. This dual-sided design enables the membrane to handle different contaminants while supporting more efficient desalination and oil separation.
By separating the membrane’s functions across different layers, the researchers prevented oil separation and solar heat generation from interfering with each other, a common challenge in single-layer designs. The hydrophobic side absorbs sunlight, converts it into heat, and drives water evaporation at the membrane surface.
Testing showed that the membrane removed more than 99.99% of oil from contaminated seawater while maintaining stable performance across different oil droplet sizes and repeated cycles. During solar desalination experiments, it achieved a water evaporation rate of about 0.05 gallons per square foot per hour, nearly three times higher than conventional single-layer membranes.
According to Prof. Jeong, the new membrane technology could support more sustainable water treatment by harnessing renewable solar energy while combining contaminant removal and freshwater production in a single platform. The integrated approach has the potential to reduce energy consumption, simplify operations, and minimize secondary waste generation compared with conventional desalination methods.
The researchers suggest that the membrane developed in this study represents a broader strategy for designing next-generation water treatment technologies. By integrating multiple treatment functions into a single membrane architecture, the approach could provide a framework for creating more efficient and adaptable systems beyond desalination applications.
Coal has long been associated with electricity generation, steelmaking, and carbon emissions. But a new technology unveiled in China aims to give the fossil fuel a very different role. Transforming it into high-value carbon materials used in industries ranging from energy storage to aerospace.
The technology, presented at an industry conference in Taiyuan, Shanxi Province, converts ordinary coal into premium carbon materials through a specialized coal liquefaction process. Developers say the approach could significantly increase the economic value of coal while reducing emissions associated with conventional coal utilization.
According to the company, the technology was jointly developed by Zhaoqing Shunxin Coal Chemical Industry Technology Co., Ltd. and Guangdong Coal-based Carbon Materials Research Co., Ltd. It was reviewed by an expert panel organized by the China International Association for the Promotion of Science and Technology in October 2025, which assessed the process as having reached an internationally leading level and recommended accelerating its commercialization.
Rather than burning coal for energy or converting it into fuels, the process focuses on extracting carbon-rich molecular structures that can serve as feedstock for advanced engineering materials.
The developers say the technology is based on quantum chemistry, separating coal molecules according to their chemical structure and bond strength. Molecules with lower bond energies are converted into oil and gas, while highly stable aromatic structures are transformed into condensed-ring pitch. A carbon-rich precursor used to manufacture advanced carbon materials.
One of the most notable aspects of the technology is the range of materials it claims can be produced. According to the developers, the condensed-ring pitch can be used to manufacture carbon foam, carbon fibers, 3D graphene, super-activated carbon, and supercapacitor-grade activated carbon. These materials are widely used across sectors including aerospace, energy storage, electronics, and advanced manufacturing.
The company also claims its carbon foam exceeds China’s Class A flame-retardancy standard and is suitable for military and aerospace applications. If these performance claims are validated at commercial scale, the technology would shift coal from being primarily an energy resource to serving as a raw material for high-performance engineered products.
The developers also highlight environmental benefits. According to the company, approximately 60% of the carbon contained in coal can be converted directly into carbon materials rather than being released through combustion. The process is also claimed to reduce carbon dioxide emissions by around two tonnes per tonne of coal processed, while generating virtually no waste gas, wastewater, or solid waste.
Economically, the approach aims to move coal further up the value chain. Instead of producing a commodity worth hundreds or thousands of yuan per tonne, the process is designed to generate advanced carbon materials that can command values ranging from tens of thousands to hundreds of thousands of yuan per tonne, depending on the final product. These figures were provided by the technology’s developers and have not been independently verified.
The technology has already taken its first step toward industrial deployment. The developers announced a cooperation agreement with the state-owned China Pingmei Shenma Group to construct a 6,000-tonne-per-year coal-based carbon materials project in Henan Province. They also said several carbon products produced using the process have completed user testing with downstream manufacturers and are now ready for commercial-scale deployment.
Although the technology still faces the challenge of proving its performance at industrial scale, it reflects a broader shift in how coal is being viewed. Rather than serving solely as a fuel, researchers are increasingly exploring its potential as a source of advanced materials, potentially opening new applications for one of the world’s most abundant carbon resources.
The Moon’s far side is overturning a long-held theory, revealing that the early Solar System’s asteroid assault may have faded slowly instead of exploding in one catastrophic burst. For decades, scientists have debated whether the early Solar System endured one sudden, catastrophic wave of asteroid strikes or a much longer period of gradually fading violence. [...]
Every space story worth its salt eventually reaches for lightspeed, the moment the engines catch and the stars streak. It is one of the oldest dreams in science fiction, so it is worth saying plainly what the physics actually allows, and what it flatly does not.
The blunt answer is that travelling at the speed of light is not merely difficult for anything with mass. It is impossible, and not in a way that a better engine will one day fix.
I am a writer with a long interest in this material, not a physicist, so treat this as a careful reading of settled science and clearly labelled speculation, kept apart.
The problem is built into relativity. The faster you push an object, the more energy each additional increment of speed demands, and the returns shrink as you approach the speed of light. To actually reach it, the energy required rises without limit. You would need an infinite amount, which is another way of saying it cannot be done.
Light itself gets to travel at light speed for one reason: photons have no mass. Massless things must move at that speed, and things with mass never can. The speed of light is not a speed limit that a clever enough spacecraft might one day break. It is closer to a feature of the shape of spacetime, the same for everyone, everywhere.
So the honest reply to “will we ever travel at the speed of light” is no, not us and not our machines, because we are made of mass.
The more interesting question is how near that wall you can press, and here the news is better, at least in principle.
There is no limit stopping you from approaching light speed, only from reaching it, and relativity throws in a strange gift on the way. As you travel faster, your own clock runs slow relative to the people you left behind. A crew moving close to light speed could in theory cross many light-years while ageing only a little, even as decades or centuries passed back on Earth. The distance does not shrink, but the time you personally spend crossing it can.
The gap between that principle and anything we can build is enormous. The fastest object we have ever launched, NASA’s Parker Solar Probe, travels at less than a tenth of one per cent of light speed. Even nature rarely gets close: a star whipped around the black hole at our galaxy’s centre reaches only about 3 per cent of light speed at its fastest, and that is one of the quickest large objects we know of.
One concept comes nearer than the rest. Breakthrough Starshot, an initiative announced in 2016, proposes to skip heavy engines entirely and instead push a fleet of gram-scale probes with a ground-based laser, accelerating tiny light sails to around 20 per cent of the speed of light. At that pace a probe could reach the nearest star system, Alpha Centauri, in roughly twenty years rather than tens of thousands.
It is important to be clear about its status. This is a design and a research programme, not a spacecraft. The engineering problems, from a laser array of unprecedented power to a sail that will not vaporise, are unsolved. But it is the nearest thing to genuine near-light-speed travel that anyone has seriously put on paper.
If you cannot go faster than light through space, general relativity leaves a stranger door ajar: rearranging space itself.
In 1994 the physicist Miguel Alcubierre found a solution to Einstein’s equations describing a warp drive, a bubble that contracts spacetime in front of a ship and expands it behind, so the ship sits still while space does the moving. Wormholes, tunnels between distant points, are also valid solutions on paper. Neither would break the local speed limit, which is what makes them so tempting.
The catch is the same for both, and it is severe. They require what physicists call exotic matter, a form of negative energy that we have never observed and do not know how to make. Early estimates for a warp bubble needed more negative energy than the mass-energy of the entire observable universe. Later work trimmed that figure dramatically, but it remains vast, and the fundamental obstacle stands.
Recent designs have taken the opposite tack, dropping the exotic matter to stay within known physics, but the versions that need no negative energy are subluminal. They stay below light speed. As things stand, the maths permits shortcuts that the physics of building them cannot yet reach.
Put together, the picture is honest rather than romantic. At the speed of light, no, not for anything with mass. Close to it, physics allows what our engineering cannot presently manage, though concepts like Starshot show what trying would look like. Faster than it, only inside equations that call for a substance nobody has ever found.
None of this is likely to change at the level of the physics. What is worth watching is the near-lightspeed end, where a laser-driven sail or some successor might one day turn a fraction of the speed of light from a diagram into a departure.
The post Travelling at the speed of light is not just hard but impossible for anything that has mass, since it would take infinite energy, so the real question is how close we could get and whether the loopholes physicists talk about are more than mathematics appeared first on Space Daily.
In 2021 a team of paleontologists led by Charles Marshall at Berkeley did something clever: they estimated not how many T. rex we have dug up, but how many ever existed.
Their headline answer was about 2.5 billion, spread across the roughly 2.4 million years the species was around, although the uncertainty ranged from 140 million to 42 billion. At any given moment, the central estimate put about 20,000 adults on the continent at once, generation after generation, for longer than modern humans have existed.
Now set that against how many we have found. The first partial skeleton recognized as T. rex was unearthed by Barnum Brown in Montana in 1902, and it became the name-bearing specimen when Henry Fairfield Osborn formally named the species in 1905.
By 2021, fewer than a hundred T. rex individuals had been found, many represented by a single fossilized bone. Only about 32 were relatively well-preserved post-juveniles held in public museums.
On Marshall’s estimate, that works out at roughly one recovered specimen for every 80 million post-juvenile animals that lived and died. Much of our physical knowledge of the animal rests on that extraordinarily narrow sample.
That fossil recovery rate that falls out is comically small.
However, for a T. rex to become a fossil you could visit, it had to die in the right place, get buried fast enough to escape scavengers and rot, survive tens of millions of years of erosion and geological change, and then happen to surface in a spot where a human being was looking. Almost nothing clears all of those hurdles.
The famous individuals bring this home. The great specimens have names, because there are few enough of them to name: Sue in Chicago, Stan, a short list of others that get written about again and again. When a single skeleton can anchor decades of research and a museum’s entire dinosaur hall, you are not looking at a well-stocked archive. You are looking at the handful of tickets that happened to win a very long lottery.
T. rex is not the poorly documented case. It is one of the better understood dinosaurs we have, a giant, sturdy-boned predator from rock we know how to read, hunted for over a century by people who badly wanted to find it.
If this is what good coverage looks like, roughly one relatively well-preserved post-juvenile in 80 million, then for most creatures that ever lived the record is not thin. It is blank. Whole species, whole families, came and went and left nothing a person will ever hold.
We are not usually reminded of that when we stand in front of the mounted skeleton. The display is confident. The posture, the coloring in the illustration beside it, the running speed on the little plaque, all of it reads as settled fact. A great deal of it is careful, honest extrapolation from a few bones and a lot of comparison with living animals, which is real science and often turns out right. But the certainty of the presentation and the scarcity of the evidence sit in an odd relationship, and I think it is worth holding both in mind at once.
None of this is a knock on paleontology. If anything it is the opposite. The impressive thing is not that our picture of T. rex has gaps. It is that anyone can say something reliable at all, starting from such a tiny fraction of the animals that lived and reasoning outward with that much care.
The wonder is not that we know so little. It is how much we have managed to reconstruct from so nearly nothing.
The post A 2021 estimate suggested that about 2.5 billion Tyrannosaurus rex lived, while only 32 relatively well-preserved post-juvenile specimens were then held in public museums — roughly one for every 80 million animals. And T. rex is one of the better represented large theropods appeared first on Space Daily.
A new study is challenging one of the most comforting assumptions in urban climate design: that adding vegetation to dense cities always makes hot weather safer. Research published in npj Urban Sustainability reports that compact, high-rise urban forms can amplify humid heat risks associated with vegetation transpiration—a process usually considered an essential cooling service. The finding does not suggest that trees and plants should be removed from cities. Instead, it reveals that the success of green infrastructure depends heavily on building geometry, airflow, humidity, and the way heat and moisture move through the urban atmosphere.
Vegetation transpiration occurs when plants release water vapor through microscopic openings in their leaves. This process consumes energy and can lower leaf and surrounding air temperatures, much like evaporation from human skin. In a well-ventilated environment, the added moisture may be dispersed efficiently, allowing evaporative cooling to provide a net thermal benefit. But in tightly packed high-rise districts, the same moisture can become trapped between buildings. The result is a more humid microclimate in which the body’s ability to cool itself through sweating is weakened.
That distinction matters because humid heat is more dangerous than air temperature alone suggests. The human body relies on evaporation to transfer heat away from the skin. When atmospheric moisture is already high, sweat evaporates more slowly, forcing the body to work harder to maintain a stable internal temperature. Heat-stress indicators such as wet-bulb temperature and the Wet-Bulb Globe Temperature account for this interaction between heat and humidity. A neighborhood with slightly lower temperatures but substantially higher humidity can therefore feel more oppressive—and pose greater health risks—than a drier location with hotter air.
The study focuses on the urban “canyon” effect created by tall buildings arranged close together. These structures can obstruct wind, reduce the exchange of air with the atmosphere above, and alter the amount of sunlight reaching streets and façades. When vegetation in such spaces transpires, the released water vapor may accumulate rather than disperse. The compact geometry can also create complex circulation patterns, with warm and moist air repeatedly moving through pedestrian-level spaces. In this setting, greenery may cool surfaces while simultaneously increasing the moisture burden experienced by people outdoors.
This is a crucial refinement of the popular idea that urban greening is universally beneficial. Plants perform several valuable functions: they provide shade, intercept solar radiation, reduce surface temperatures, store carbon, and improve the visual and psychological quality of public space. Yet their cooling performance is not fixed. It changes with species, soil moisture, canopy density, irrigation, wind conditions, building height, street width, and background humidity. The new research emphasizes that these factors must be evaluated together rather than treating vegetation as an isolated solution to urban heat.
The implications are particularly significant for rapidly growing cities where vertical development is being used to accommodate rising populations. High-rise construction can reduce land consumption, but dense towers may produce localized atmospheric conditions that differ dramatically from those in surrounding neighborhoods. A cooling strategy designed for an open suburban street may behave differently in a narrow urban canyon surrounded by tall façades. Planners could therefore face a difficult balancing act: maximizing shade and ecological benefits without creating stagnant pockets where moisture and heat combine into dangerous conditions.
The findings also raise questions about how cities measure the success of climate adaptation projects. A street may record a lower surface temperature after trees are planted, yet still expose pedestrians to greater physiological stress if humidity increases and air movement declines. This means future assessments should include multiple variables, including air temperature, relative humidity, wind speed, radiant heat, and human thermal response. Satellite observations and conventional weather stations may not fully capture conditions at street level, where building walls, tree canopies, pavement, and human activity interact within a few meters.
The research is likely to intensify debate over “smart” urban greening rather than green infrastructure in general. Possible responses include selecting vegetation according to local humidity and wind conditions, designing wider or better-connected ventilation corridors, combining trees with reflective or permeable surfaces, and ensuring that shaded areas do not become poorly ventilated enclosures. Building orientation and spacing may be as important as the number of trees planted. Irrigation practices could also matter, since additional water supplied to vegetation may increase transpiration during precisely the periods when atmospheric moisture is already high.
For residents, the message is both cautionary and practical. A leafy street can still be healthier than an exposed one, particularly when shade reduces direct solar radiation. But during extreme heat, people should not assume that every green space offers the same level of protection. Dense, humid, windless areas may require additional measures such as cooling centers, drinking-water access, timed outdoor activities, and heat alerts that account for humidity. The study’s central contribution is to show that urban climate risk is not determined by temperature alone—or by the presence of greenery alone—but by the interaction between city form, plant physiology, and human vulnerability.
As climate change increases the frequency and intensity of heat extremes, these interactions could become more consequential. The research presents cities with a deceptively simple lesson: cooling the urban environment is not just a matter of adding more plants. It requires understanding where the water released by vegetation goes, how buildings control its movement, and how the resulting air feels to a human body. In the race to make cities greener, the next generation of design may need to be equally focused on keeping them breathable.
Subject of Research: The relationship between compact high-rise urban form, vegetation transpiration, humidity, and humid heat risk.
Article Title: Urban high-rise compact form amplifies humid heat risk from vegetation transpiration.
Article References: Zhang, Y., Yang, K., Zhu, Y. et al. “Urban high-rise compact form amplifies humid heat risk from vegetation transpiration.” npj Urban Sustainability (2026). https://doi.org/10.1038/s42949-026-00459-1
Image Credits: AI Generated
DOI: 10.1038/s42949-026-00459-1
Imagine placing two thermometers on Mars at noon. One lies flat against dark, sunlit soil near the equator. The other hangs roughly at the height of a standing person’s head.
The lower thermometer could read 24 degrees Celsius, a mild spring day by Earth standards. The upper one could remain at or below freezing. Nothing separates them except about two metres of the thinnest lower atmosphere any person in a spacesuit is likely to encounter.
NASA uses almost exactly this comparison in its Mars facts guide: spring at your feet and winter at your head. It sounds like a piece of planetary trivia, but it captures something fundamental about Martian weather. On Earth, the air is usually effective enough at moving heat that we treat the temperature of the ground and the temperature of the atmosphere as parts of the same experience. On Mars, they can behave like neighbouring but weakly connected systems.
The 24-degree figure is a plausible local surface temperature, not a promise about every equatorial noon. Season, dust, slope, colour, elevation and the material underfoot all matter. The real point is the vertical contrast. Sunlight can briefly warm the ground above freezing while the sparse gas above it stays bitterly cold.
A weather report on Earth normally gives air temperature measured in shade, not the temperature of sunlit concrete or beach sand. Those surfaces may be far hotter than the reported maximum. We know the distinction in daily life, but the atmosphere mixes enough heat through its lowest layers that a standing person does not ordinarily place their shoes in one season and their face in another.
Mars pushes the same distinction to an extreme. The ground absorbs sunlight and converts it to heat. A thermal infrared instrument can measure the energy radiated by that skin of dust and rock. A separate sensor measures the gas surrounding a rover. Both values are real, but they describe different material with very different capacities to absorb, store and transport energy.
That is why the warmest number quoted for Mars is usually a surface temperature. The air is much less willing to follow it. Even at the equator, a patch of ground that has crossed zero degrees does not imply a warm afternoon atmosphere.
The atmosphere at the Martian surface has less than one per cent of the pressure of Earth’s atmosphere at sea level. It is mostly carbon dioxide, but the abundance of a greenhouse gas by percentage is not enough to make a strong greenhouse blanket. The total quantity of gas overhead is small.
On Earth, molecules colliding with warm ground pick up energy. Convection, turbulence and wind then move that energy upward and sideways. Water vapour, clouds and oceans store and redistribute still more heat. Mars has weather, clouds and vigorous dust storms, but its near-surface gas contains far fewer molecules through which heat can travel.
This thinness has appeared repeatedly in the Mars machines I have written about. Ingenuity had to spin unusually large rotors at extraordinary speed to fly in air around one per cent as dense as Earth’s. MOXIE needed a pump to gather enough carbon dioxide before it could make oxygen. The same scarcity that makes lift and gas collection difficult also weakens the exchange of heat between soil and atmosphere.
The result is not zero heat transfer. The warmed surface drives turbulence and convective vortices, including dust devils. It simply cannot force the lowest two metres towards one uniform temperature as efficiently as Earth’s denser air usually does.
This is no longer only a thought experiment. The Mars Environmental Dynamics Analyzer, or MEDA, on Perseverance measures temperatures in and around Jezero Crater. Its sensors distinguish the surface from atmospheric layers at different heights.
NASA reported typical early MEDA observations in which the surface rose from about minus 83 degrees Celsius before dawn to 5 degrees at noon, while the air remained between about minus 83 and minus 23 degrees. Those particular days did not reproduce the 24-degree example, but they showed the same separation between a rapidly heated surface and colder air.
A 2023 analysis of MEDA measurements in the Journal of Geophysical Research: Planets quantified the vertical structure. For a set of repeatedly observed sols, the daytime temperature difference was concentrated in the first 1.45 metres above the ground. Near noon, the gradient reached about 26 degrees Celsius per metre.
The precise value changes with conditions, and it should not be applied to every place and season. Yet it gives physical substance to NASA’s spring-and-winter comparison. The lowest part of the Martian atmosphere can contain an enormous temperature change across the height of one human body.
Curiosity saw the distinction too. In one early sequence at Gale Crater, ground temperatures ranged from 3 to minus 91 degrees Celsius while air temperatures ranged from minus 2 to minus 75. The ground achieved both the warmer daytime peak and the colder nighttime minimum. It responded faster in both directions.
Not every Martian surface heats at the same rate. Fine, loose dust has low thermal inertia. It changes temperature quickly when sunlight arrives and quickly loses that heat after sunset. Solid rock conducts and stores more energy, so it warms and cools more slowly. Particle size, cementation and material buried beneath the surface all affect the curve.
Planetary scientists use thermal inertia to interpret those differences from orbit. A region that remains relatively warm after sunset may contain rock, bedrock or coarser material. A dusty surface may produce a sharper afternoon peak and a steeper fall into night.
Colour and orientation matter as well. Darker ground generally absorbs more sunlight. A slope facing the Sun receives energy at a more direct angle than a shaded one. Airborne dust can reduce the sunlight reaching the surface while also changing how radiation moves through the atmosphere. Elevation changes the already low pressure.
There is therefore no single Martian noon temperature. I made a related point when writing about the immense, gently rising landscape of Olympus Mons: a global description can conceal what a person would encounter at ground level. On Mars, even two nearby patches of terrain can follow different thermal schedules.
The image of warm boots risks making an equatorial noon sound more hospitable than it is. An unprotected person could not stand there and compare sensations. The pressure is too low for the human body, the atmosphere contains almost no oxygen, ultraviolet and ionising radiation reach the surface, and liquid water is unstable under most present conditions.
A real astronaut would be separated from both ground and air by a pressure suit, insulation, boots and a controlled thermal system. The suit would manage heat generated by the body while limiting heat gained from sunlight and lost through radiation, contact and the surrounding gas. It would not simply transmit a pleasant 24 degrees from the soil to the foot.
There is another counterintuitive detail. Mars can have fast winds, but because the gas is so thin, those winds carry less force and exchange less heat than winds of the same speed on Earth. The cold air at head height would not feel like an ordinary terrestrial winter gale. Without a suit, the low pressure would be the immediate emergency. With one, thermal engineering determines the experience.
This is why my earlier look at the difficulty of building a home on Mars could not reduce the problem to an average temperature. A habitat must survive daily cycling, cold-soaked nights, sunlit surfaces, dust, radiation and a near-vacuum while maintaining one narrow indoor climate for people and equipment.
The warm ground is temporary. Once the Sun drops, a dusty surface radiates energy into the cold sky and has little atmosphere above it to return that energy. The same weak coupling that allows soil to become much warmer than the air at noon permits it to plunge below the air during the night.
That daily swing has shaped the history of Mars exploration. Solar-powered rovers conserve energy through cold periods and use heaters to keep critical components within operating limits. Batteries, lubricants, cameras and electronics experience a thermal environment that expands and contracts every sol. Opportunity ultimately endured far beyond its original design, but as I wrote in the account of its fourteen-and-a-half-year journey, sunlight remained both its power source and its final vulnerability.
The spring-underfoot image lasts only because sunlight is arriving faster than the particular ground can shed it. It says nothing about the night before, the night ahead or a shaded patch a few steps away.
There is something useful about reducing Martian climate to the height of a person. Global averages tell us that Mars is cold. Pressure figures tell us that its atmosphere is thin. A vertical temperature profile shows what those statements mean together.
Sunlight crosses the sparse atmosphere and heats the soil. The soil tries to warm the gas touching it. There are too few molecules to distribute that energy efficiently, so a steep gradient forms just above the surface. Turbulence carries some heat upward, but the afternoon never becomes uniform. Then sunset removes the source and the ground rapidly gives back what it gained.
On Earth, weather surrounds us. On Mars, the most dramatic piece of weather may fit between the soles of a pair of boots and the top of a helmet.
NASA’s comparison is memorable because it compresses an alien climate into human proportions. Spring and winter can occupy the same standing person, not because Mars has found a loophole in temperature, but because it lacks the thick, mixing atmosphere that quietly makes our own experience of temperature feel coherent.
The post Mars has such thin air that around noon near the equator, sunlit ground beneath your boots could reach 24 degrees Celsius while the air around your head remained below freezing — allowing one standing person to span temperatures resembling spring and winter at the same time. appeared first on Space Daily.
A single neuron may help the brain recognize what it sees, track what the body is doing, and guide a decision, all at the same time. Most neurons may be far more versatile than scientists once thought. In a major study published in Nature, researchers analyzed more than 14,000 individual neurons across 43 regions of [...]The dreaming brain surges with energy, yet its neurons may consume it faster than they can replenish it. A new mouse study from Tohoku University has uncovered a surprising energy imbalance during rapid eye movement (REM) sleep. As the brain entered this dream-rich stage, blood volume increased across the cortex, and astrocytes accumulated more metabolic [...]
Calling Ganymede a moon is correct, but it does very little to prepare us for what the object actually is.
It is the largest moon in the Solar System, with a diameter of about 5,262 kilometres. It has an iron-rich core, a rocky mantle, an immense layer of water and ice, an old and geologically complicated surface, a thin atmosphere, auroras and a magnetic field generated inside the moon itself. If it travelled around the Sun rather than Jupiter, nobody encountering it for the first time would mistake it for a minor piece of debris.
That does not mean Ganymede has been misclassified. A moon is defined by what it orbits, not by how geologically accomplished it appears. But Ganymede is a useful reminder that the word describes an orbital relationship, not a level of complexity. This is a full-sized world living as one component of the Jupiter system.
The cleanest comparison begins with size. JPL lists Ganymede’s mean radius as 2,631.2 kilometres. Mercury’s mean radius is 2,439.4 kilometres. Ganymede is therefore almost 8 per cent wider than the smallest planet.
It is not, however, more massive. Ganymede has only about 45 per cent of Mercury’s mass. The difference is composition. Mercury is an unusually dense, metal-rich planet, while Ganymede is a much lighter mixture of rock and water ice. Mercury’s average density is about 5.43 grams per cubic centimetre; Ganymede’s is about 1.94.
This distinction matters because the familiar sentence, “Ganymede is bigger than Mercury,” can accidentally create the wrong mental image. The moon has a larger volume, but much less material packed inside it. Its surface gravity is only around 15 per cent of Earth’s, lower even than the Moon’s.
The comparison also exposes why size alone cannot decide whether something is a planet. Mercury independently circles the Sun. Ganymede completes an orbit around Jupiter every 7.15 days. Its status follows that architecture, even though its body is more planet-like than the word moon tends to imply.
Small Solar System bodies are often imagined as frozen mixtures that never became warm enough to organise themselves internally. Ganymede did. NASA’s current overview describes a deep metallic core, a surrounding rock shell and an outer system of water and ice. In other words, the moon differentiated into layers, as the rocky planets did.
The surface keeps part of that history. Dark, heavily cratered terrain records very old ground. Brighter regions are crossed by long grooves and ridges, evidence that the crust was stretched, fractured and resurfaced. Ganymede is no longer as visibly active as neighbouring Io, but it is not a featureless ball that simply froze in place.
The contrast with its parent planet is almost comic. As I explored in an earlier article about why there is no solid surface on Jupiter to land on, the giant planet becomes progressively denser with depth until hydrogen behaves like an electrically conducting metal. Ganymede, despite orbiting that enormous fluid world, offers recognisable ground, internal layers and geological provinces. The moon is the place with the planetary surface; the planet is not.
The statement that Ganymede may contain more water than Earth does not describe an open sea. No camera has looked through the crust, and no probe has sampled the liquid. The evidence comes from several indirect measurements, including how Ganymede responds to Jupiter’s changing magnetic environment.
One especially elegant test used the moon’s auroras. Jupiter’s magnetic field should make those glowing bands rock back and forth by about six degrees. In Hubble observations, they moved by only about two degrees. A conductive, salty ocean beneath the crust provided the best explanation, because electrical currents in the water generate a secondary magnetic response that damps the motion.
The 2015 model associated with those observations placed an ocean roughly 100 kilometres thick beneath about 150 kilometres of mostly ice. Those figures are estimates, not a sonar reading. Other models allow a layered arrangement in which liquid water is separated by different phases of high-pressure ice, closer to a club sandwich than one unbroken sea.
Even with that uncertainty, Ganymede’s total water inventory may exceed all the water on Earth’s surface. The careful wording matters. Earth also stores water inside its mantle, and Ganymede’s water is not necessarily all liquid at once. The comparison concerns the moon’s enormous combined water layer and the oceans, ice and surface water visible on Earth.
This is part of the larger change I wrote about in the expansion of the habitable-zone idea beyond sunlight. It also explains why the list of credible hidden-ocean moons keeps growing. Yet water volume alone does not make Ganymede habitable. If high-pressure ice separates the ocean from rock below, the chemical exchange available at a rocky seafloor may be limited. The depth that protects the water also makes it extraordinarily difficult to investigate.
Ganymede’s most unusual property is not its size or even its water. It is the only moon known to generate its own intrinsic magnetic field. NASA’s Galileo spacecraft detected the field during close encounters beginning in 1996. The leading explanation is a dynamo operating in a liquid, electrically conducting part of the metallic core, broadly the same physical mechanism that sustains Earth’s global field.
The distinction between intrinsic and induced fields is important. The buried saltwater ocean appears to develop an induced response as Jupiter’s external field changes around it. The stronger, permanent field comes from much deeper inside Ganymede. Measurements and modelling describe a small Ganymede magnetosphere nested within Jupiter’s much larger one.
That arrangement produces auroras near the moon’s poles, but it should not be confused with an Earth-like protective cocoon. Ganymede has only a very tenuous atmosphere, and it remains immersed in Jupiter’s radiation and plasma environment. A magnetic field can organise the charged particles around the moon without turning its surface into a safe refuge.
There is still an active question about how such a small world has retained the fluid motions needed for a dynamo. Space Daily recently examined the proposal that Ganymede’s core may still be evolving. The details are not settled, but the field is direct evidence that the moon is not internally inert.
It is tempting to describe Ganymede as a planet that happens to have been captured by Jupiter. That would go too far. Ganymede’s history and present behaviour are inseparable from the system it inhabits.
Its orbit participates in the Laplace resonance with Europa and Io. For every orbit Ganymede completes, Europa completes about two and Io about four. Their recurring gravitational tugs prevent the orbits from becoming perfectly circular and help redistribute energy through the moons. I described the same mechanism in an article about Europa’s place in Jupiter’s three-moon gravitational machine.
Past tidal heating may have helped Ganymede separate into its present layers, and Jupiter controls the magnetic environment in which its ocean signal is measured. The moon is also tidally locked, keeping the same face towards Jupiter as it travels around the planet. Its planet-like qualities therefore do not make it independent. They show how elaborate a satellite can become while remaining physically bound to a larger system.
This is the more interesting lesson than a debate over labels. A moon can have the diameter of a planet, the interior architecture of a planet and a dynamo usually associated with planets, while its geology and energy budget remain shaped by a relationship no solitary planet has.
Most of what we know about Ganymede comes from fly-bys, remote observations and measurements made during brief passages. ESA’s Jupiter Icy Moons Explorer, or JUICE, is designed to change the scale of the investigation.
JUICE launched in April 2023 and is scheduled to reach Jupiter in July 2031. After a tour of the Jovian system, the mission plan calls for insertion into orbit around Ganymede in December 2034. If successful, it will become the first spacecraft to orbit a moon beyond Earth’s own.
Its instruments are meant to treat Ganymede as a system rather than a single target. Radar will probe the icy shell. Magnetic measurements will separate signals from the core, ocean and Jupiter. Laser altimetry, radio science and cameras will examine the moon’s shape, gravity, surface and response to tides. Together, those observations should constrain how thick the ice is, how the water is arranged and how the deep interior keeps its field alive.
Ganymede does not need to be promoted from moon to planet for any of this to count. “Moon” tells us that it goes around Jupiter. “World” tells us that it has a history, structure and physical identity worth studying on its own terms. Ganymede is both, and the tension between those descriptions is exactly what makes it so revealing.
The post Ganymede is a moon, yet it is larger than the planet Mercury, may contain more water than exists on Earth’s surface, and even generates its own magnetic field, making it less like a conventional moon than a full-sized world that happens to orbit Jupiter. appeared first on Space Daily.
Login