Category: 7. Science

Scientists found AMORE6, a galaxy almost free of heavy elements. Its existence strongly supports key predictions of the Big Bang model.

Our knowledge of the Universe begins with the Big Bang, the moment when cosmic expansion first began. During this event, a process called Big Bang nucleosynthesis produced only the lightest elements: hydrogen, helium, and trace amounts of lithium. Heavier elements, which astrophysicists refer to as metals, were created later in the hearts of stars that lived and died after this first epoch.

The earliest generation of stars, known as Population III stars, were the first to forge these heavier elements through stellar nucleosynthesis. These stars themselves contained no metals, or at most extremely small amounts, and their life cycles enriched the Universe with its first metals. Because stars are born in galaxies rather than in isolation, there must also have been Population III galaxies whose stellar populations contained no metals at all.

Despite progress in understanding cosmic history, significant gaps remain. One of the most important missing pieces is evidence for these Population III galaxies. Theory predicts that some early galaxies, observed at high redshifts, should display zero metallicity. Confirming their existence would provide crucial support for our current cosmological framework.

Surprising results from JWST

The James Webb Space Telescope (JWST) has already reshaped expectations by revealing massive, well-developed galaxies far earlier in cosmic history than models had predicted. According to previous understanding, galaxies of that size and maturity should not have appeared so soon after the Big Bang. These discoveries have forced astronomers to reconsider how quickly galaxies formed and evolved.

Yet, even with its remarkable capabilities, JWST has not definitively identified a zero-metallicity galaxy. While it has observed galaxies that emerged only a few hundred million years after the Big Bang, none of them have yet shown the complete absence of metals predicted for true Population III systems.

The role of OIII emissions

Oxygen plays an essential role in this search. According to cosmological models, the earliest galaxies should contain only hydrogen and helium, with no oxygen or other heavier elements. Astronomers use the OIII emission line in spectroscopy to study galaxies: it reveals ongoing star formation and is especially effective at probing very distant, high-redshift systems. JWST, with its sensitivity, has made these measurements even more powerful.

In primitive galaxies, strong OIII emissions can indicate very low metallicity. Conversely, weak OIII signals suggest galaxies formed under conditions unlike those seen today. Until recently, no convincing example had been found.

That may now be changing. New research submitted to Nature reports the possible discovery of a galaxy that fits the criteria for being pristine. The study is led by Takahiro Morishita, a staff scientist at the Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology.

“The existence of galaxies with no elements such as Oxygen – formed by stars after Big Bang nucleosynthesis – is a key prediction of the cosmological model,” the researchers write. “However, no pristine “zero-metallicity” Population III galaxies have been identified so far.”

Confirming the Big Bang model

Until now. Morishita and his co-authors have found a galaxy that fits the description. They detected it at redshift z = 5.725, meaning its light was emitted when the Universe was only about 900 million to 1 billion years old. It’s named AMORE6 and was detected through gravitational lensing. This magnified and duplicated the images of the galaxy, making it easier to observe. The JWST found Hβ emissions, an important line in astronomy used to measure galaxies in different ways, but it didn’t detect any oxygen. That means its metallicity is very low. “The absence of [O iii] immediately indicates that AMORE6 harbors a very low-metallicity, near pristine, interstellar medium,” the authors explain.

The galaxy also shows low stellar-mass and an extremely compact morphology. “These properties are consistent with massive star formation in a pristine or near-pristine environment,” the authors write. The thing is, this galaxy isn’t as old as some earlier, fully-formed galaxies the JWST found. It’s somewhat puzzling that this strong example of a pristine and low-metallicity star-forming environment was found almost one billion years after the Big Bang.

More studies will be needed to confirm these findings and understand them in greater detail. But the detection suggests that we are on the right track in understanding Nature.

“The finding of such an example at a relatively late time in cosmic history is surprising,” the researchers write. “However, regardless of cosmic epoch, the identification of a potentially pristine object is a key validation of the Big Bang model.”

Reference: “Pristine Massive Star Formation Caught at the Break of Cosmic Dawn” by Takahiro Morishita, Zhaoran Liu, Massimo Stiavelli, Tommaso Treu, Pietro Bergamini and Yechi Zhang, 31 July 2025, arXiv.
DOI: 10.48550/arXiv.2507.10521

Adapted from an article originally published on Universe Today.

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In one of the most unusual natural discoveries of recent years, scientists have observed what they call “salt snow” falling beneath the surface of the Dead Sea. Unlike normal snowfall, this strange process happens underwater as halite crystals form and descend like snowflakes. Researchers believe this rare phenomenon may help explain how massive underground salt structures such as chimneys, domes, and kilometer-thick deposits are created. Triggered by climate change, evaporation, and water diversion, the “salt snow” not only reshapes the Dead Sea but also offers clues to Earth’s geological past.

What is ‘salt snow’ of Dead Sea

Salt snow refers to the precipitation of halite crystals within the Dead Sea. Normally, salt crystallization is seen in shallow or cold water layers, but here it occurs year-round, even during summer. The process begins when surface water becomes warmer and saltier due to evaporation. This dense water cools and sinks, while colder, less salty water from below rises. The mixing of these layers triggers crystal formation in mid-water zones, creating the illusion of snow falling underwater.

How the Dead Sea became a natural laboratory

The Dead Sea is the lowest point on Earth’s surface and one of the saltiest water bodies in the world, making it uniquely suited for such phenomena. Historically, its water remained layered and stable. But since the 1980s, reduced inflow from the Jordan River and intensified evaporation have disrupted this balance. As a result, annual mixing of water layers now fuels continuous salt crystallization. Unlike other seas such as the Red Sea or the Mediterranean, where similar processes ended millions of years ago, the Dead Sea remains active, offering a living glimpse into Earth’s geological history.

Salt giants beneath the surface

These falling crystals accumulate over time, forming vast salt structures beneath the seabed. Known as salt giants, chimneys, and domes, they can reach more than a kilometer in thickness and extend over vast distances. Such formations are crucial for geologists because they mirror conditions during the Messinian Salinity Crisis over 5 million years ago, when the Mediterranean dried up and massive salt deposits were left behind. The Dead Sea now serves as a smaller-scale model of that ancient process.

Climate change and its role

The salt snow is not just a scientific curiosity, it reflects wider environmental shifts. Climate change, combined with human-driven freshwater diversion, has caused the Dead Sea’s water level to drop by about one meter per year. This accelerates salinity increases and alters stratification, intensifying salt precipitation. The unusual “snowfall” thus acts as a visible marker of climate stress on fragile ecosystems, highlighting how human activities and warming temperatures reshape natural processes.

Why it matters globally

Understanding the Dead Sea’s salt snow provides more than local insights. These formations record climate fluctuations and hydrological imbalances, offering a geological archive of environmental change. On a broader scale, studying this phenomenon could shed light on how coastal systems respond to rising salinity and climate change worldwide. It also informs research into erosion, resource extraction, and the stability of other saltwater basins.

McGill University researchers have developed a novel method to replicate four types of microplastics commonly found in the environment, providing researchers with a standardized approach to study their toxic effects.

“We  regularly see news about microplastics in our bodies or the environment. While this news is scary, we have yet to fully comprehend their effects in these places,” said Audrey Moores, Professor in the Department of Chemistry and co-author of the paper, published in Environmental Science and Technology.

“We are still very far from any quantitative  understanding of what it means to have microplastics in all these places. Consequently, it’s really critical for public policy development that we develop a standardized platform for testing their toxicity,” Moores added.

McGill PhD Candidate Jasmine Hong is the paper’s lead author.  Subhasis Ghoshal, Professor of Civil Engineering, co-supervised the research.

The struggle to find – or make – uniform samples

Scientists have struggled to obtain or create standardized microplastic samples. Environmental collection is costly and complicated, often yielding a mix of plastic types. Makers of samples in the lab have been unable to control their size, roughness and surface chemistries precisely enough, factors that are crucial to understanding toxicity.

The researchers’ method addresses those gaps with nano-level precision. 

“Researchers have made microplastics in the lab, but we were still missing a method that would allow us to make specific sizes of microplastics with desired  surface chemistry and roughness. These parameters are critical because we know that they are key in determining the toxicity of nanomaterials,” Moores said.

Their approach also produces smaller microplastic samples than typically seen in lab settings, which Moores said is vital for toxicological analysis.

A three-step recipe for replication

The teams used a three-step approach to fabricate the microplastics. First, cryomilling, or grinding particles under cold temperatures, allowed them to control size and to make smaller particles. Second, they exposed the particles to UV light, which helped them control surface oxidation. Third, they used a chemical reaction to roughen the plastics’ surface.

The result is a clear, reproducible strategy for creating microplastics in the lab.

“We did a very in-depth analysis to really understand how to make the smallest copies, which are harder to make. Particle size is a key feature defining how microparticles can interact with organs. The smaller the particle, the more effects it can have,” Moores said. “This will allow us to test for toxicity in a much more standardized fashion to truly understand the effects of microplastics.”

PhD candidate Jasmine Hong is already working on next steps.

“I want to use these models to test how microplastics interact with other pollutants or toxic compounds,” she said.

About this study

“Accelerated Weathering of Microplastics: A Systematic Approach to Model Microplastic Production,” by Jasmine Hong, Olivia Hengelbrok, Julien Gigault, Subhasis Ghoshal and Audrey Moores, was published in Environmental Science and Technology.

The research was funded by the Natural Science and Engineering Research Council of Canada (NSERC), the NSERC-Collaborative Research and Training Experience in Sustainable Electronics and Eco-Design, the Canada Foundation for Innovation, the Fonds de recherche du Québec – Nature et technologies and the McGill Sustainability Systems Initiative.

It may not be as dramatic as a total solar eclipse, but there’s something equally epic about watching Earth’s shadow gradually engulfing and coloring the moon during a total lunar eclipse. The next total lunar eclipse — colloquially called a “blood moon” — will occur on Sept. 7-8, 2025, but it won’t be another 177 days until the phenomenon is visible from parts of North America, on March 2-3, 2026.

An eclipse of the moon is a global event, happening at a specific time, and only those on the night side of Earth see it. On Sept. 7-8, North America won’t be on the night side, with prime visibility limited to Africa, India, China and Australia. Western Europe will get a glimpse of the event at moonrise, but mostly misses out on the event, too. That’s a shame because the Sept.7-8 total lunar eclipse will see the lunar surface turn reddish for 82 minutes, just as it did on March 13-14, 2025, when moongazers in North America were in prime position for some spectacular photos.

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Today in the history of astronomy, Viking 2 touches down.

Climate models are complex, just like the world they mirror. They simultaneously simulate the interacting, chaotic flow of Earth’s atmosphere and oceans, and they run on the world’s largest supercomputers.

Critiques of climate science, such the report written for the Department of Energy by a panel in 2025, often point to this complexity to argue that these models are too uncertain to help us understand present-day warming or tell us anything useful about the future.

But the history of climate science tells a different story.

The earliest climate models made specific forecasts about global warming decades before those forecasts could be proved or disproved. And when the observations came in, the models were right. The forecasts weren’t just predictions of global average warming – they also predicted geographical patterns of warming that we see today.

These early predictions starting in the 1960s emanated largely out of a single, somewhat obscure government laboratory outside Princeton, New Jersey: the Geophysical Fluid Dynamics Laboratory. And many of the discoveries bear the fingerprints of one particularly prescient and persistent climate modeler, Syukuro Manabe, who was awarded the 2021 Nobel Prize in physics for his work.

Manabe’s models, based in the physics of the atmosphere and ocean, forecast the world we now see while also drawing a blueprint for today’s climate models and their ability to simulate our large-scale climate. While models have limitations, it is this track record of success that gives us confidence in interpreting the changes we’re seeing now, as well as predicting changes to come.

Forecast No. 1: Global warming from CO2

Manabe’s first assignment in the 1960s at the U.S. Weather Bureau, in a lab that would become the Geophysical Fluid Dynamics Laboratory, was to accurately model the greenhouse effect – to show how greenhouse gases trap radiant heat in Earth’s atmosphere. Since the oceans would freeze over without the greenhouse effect, this was a key first step in building any kind of credible climate model.

To test his calculations, Manabe created a very simple climate model. It represented the global atmosphere as a single column of air and included key components of climate, such as incoming sunlight, convection from thunderstorms, and his greenhouse effect model.

Despite its simplicity, the model reproduced Earth’s overall climate quite well. Moreover, it showed that doubling carbon dioxide concentrations in the atmosphere would cause the planet to warm by about 5.4 degrees Fahrenheit (3 degrees Celsius).

This estimate of Earth’s climate sensitivity, published in 1967, has remained essentially unchanged in the many decades since and captures the overall magnitude of observed global warming. Right now the world is about halfway to doubling atmospheric carbon dioxide, and the global temperature has warmed by about 2.2 F (1.2 C) – right in the ballpark of what Manabe predicted.

Other greenhouses gases such as methane, as well as the ocean’s delayed response to global warming, also affect temperature rise, but the overall conclusion is unchanged: Manabe got Earth’s climate sensitivity about right.

Forecast No. 2: Stratospheric cooling

The surface and lower atmosphere in Manabe’s single-column model warmed as carbon dioxide concentrations rose, but in what was a surprise at the time, the model’s stratosphere actually cooled.

Temperatures in this upper region of the atmosphere, between roughly 7.5 and 31 miles (12 and 50 km) in altitude, are governed by a delicate balance between the absorption of ultraviolet sunlight by ozone and release of radiant heat by carbon dioxide. Increase the carbon dioxide, and the atmosphere traps more radiant heat near the surface but actually releases more radiant heat from the stratosphere, causing it to cool.

This cooling of the stratosphere has been detected over decades of satellite measurements and is a distinctive fingerprint of carbon dioxide-driven warming, as warming from other causes such as changes in sunlight or El Niño cycles do not yield stratospheric cooling.

Forecast No. 3: Arctic amplification

Manabe used his single-column model as the basis for a prototype quasi-global model, which simulated only a fraction of the globe. It also simulated only the upper 100 meters or so of the ocean and neglected the effects of ocean currents.

In 1975, Manabe published global warming simulations with this quasi-global model and again found stratospheric cooling. But he also made a new discovery – that the Arctic warms significantly more than the rest of the globe, by a factor of two to three times.

This “Arctic amplification” turns out to be a robust feature of global warming, occurring in present-day observations and subsequent simulations. A warming Arctic furthermore means a decline in Arctic sea ice, which has become one of the most visible and dramatic indicators of a changing climate.

Forecast No. 4: Land-ocean contrast

In the early 1970s, Manabe was also working to couple his atmospheric model to a first-of-its-kind dynamical model of the full world ocean built by oceanographer Kirk Bryan.

Around 1990, Manabe and Bryan used this coupled atmosphere-ocean model to simulate global warming over realistic continental geography, including the effects of the full ocean circulation. This led to a slew of insights, including the observation that land generally warms more than ocean, by a factor of about 1.5.

As with Arctic amplification, this land-ocean contrast can be seen in observed warming. It can also be explained from basic scientific principles and is roughly analogous to the way a dry surface, such as pavement, warms more than a moist surface, such as soil, on a hot, sunny day.

The contrast has consequences for land-dwellers like ourselves, as every degree of global warming will be amplified over land.

Forecast No. 5: Delayed Southern Ocean warming

Perhaps the biggest surprise from Manabe’s models came from a region most of us rarely think about: the Southern Ocean.

This vast, remote body of water encircles Antarctica and has strong eastward winds whipping across it unimpeded, due to the absence of land masses in the southern midlatitudes. These winds continually draw up deep ocean waters to the surface.

Manabe and colleagues found that the Southern Ocean warmed very slowly when atmospheric carbon dioxide concentrations increased because the surface waters were continually being replenished by these upwelling abyssal waters, which hadn’t yet warmed.

This delayed Southern Ocean warming is also visible in the temperature observations.

What does all this add up to?

Looking back on Manabe’s work more than half a century later, it’s clear that even early climate models captured the broad strokes of global warming.

Manabe’s models simulated these patterns decades before they were observed: Arctic Amplification was simulated in 1975 but only observed with confidence in 2009, while stratospheric cooling was simulated in 1967 but definitively observed only recently.

Climate models have their limitations, of course. For instance, they cannot predict regional climate change as well as people would like. But the fact that climate science, like any field, has significant unknowns should not blind us to what we do know.

Ice does not usually show up in conversations about electricity. A new study reports that ordinary frozen water generates electric charge when it bends, and the measured response is on the same order as benchmark electroceramics such as titanium dioxide and strontium titanate.

The research also links this behavior to how storms build up charge, offering a fresh way to think about why lightning starts inside clouds. It adds a surface twist at extremely low temperatures that could matter in special environments.

Ice and flexo-electricity

Scientists call this effect flexo-electricity, the coupling between electric polarization and strain gradients in an insulator. A comprehensive review explains why any solid can show some flexoelectric response when it is bent unevenly or shaped with strong curvature.

This is not the same as being piezoelectric, which requires a crystal structure that lacks inversion symmetry and creates charge directly under uniform compression or tension. Flexo-electricity does not need that symmetry break, so it can appear in materials that fail the piezoelectric test.

Dr. Xin Wen of the Catalan Institute of Nanoscience and Nanotechnology (ICN2), located on the Universitat Autonoma de Barcelona campus, helped lead the experiments and modeling. The team combined precise bending tests with theory to tie the electrical signal to the mechanical shape of the ice.

Testing a slab of ice

The researchers shaped an ice slab, placed it between metal plates, then bent it in a controlled way while monitoring the voltage that appeared. The signal tracked how strongly the slab curved, which is exactly what flexo-electricity predicts.

“We discovered that ice generates electric charge in response to mechanical stress at all temperatures,” said Dr. Wen.

The tests showed that ice keeps producing a strong electrical signal across the whole range of temperatures where it stays solid, right up until it melts. That puts frozen water in the same league as some engineered materials, like certain oxides, that are commonly used in electronic sensors and capacitors.

At extremely low temperatures, the researchers also noticed a very thin surface layer of ice that could flip its electrical orientation when an outside electric field was applied. This layer acts like a ferroelectric, but only on the surface and not throughout the entire block of ice.

Ice interacting with its environment

Surface structure can dramatically change how ice interacts with its surroundings. In thunderclouds, tiny ice crystals crash into soft hailstones known as graupel, and those collisions shift electric charge from one particle to another.

Studies in the lab and in real storms have shown that these encounters separate charge in ways that depend on temperature, building up the electric fields that allow lightning to form.

Flexo-electricity offers an additional microphysical pathway for those particles to charge up during bouncy, irregular impacts that bend and twist their surfaces. The new measurements match the scale of charge transfers inferred for real collisions, which helps knit lab physics to storm electrification without requiring piezoelectricity.

A clear overview from NOAA outlines how separate charge regions form in a storm, build an electric field, and finally trigger a lightning discharge. The present work slides a mechanical bending effect into that picture, adding a way for collisions to do electrical work when particles deform unevenly.

This matters most in the mixed phase region of a storm where supercooled droplets coat graupel and ice crystals ricochet through updrafts. Nonuniform stresses there are normal, so a bending driven mechanism is a natural candidate.

Ice powers new electricity tech

Ice is cheap to make, it molds into shapes easily, and it is abundant in cold places. Flexoelectric transduction could let engineers build simple sensors or pressure to voltage converters in situ, using water and metal contacts without high temperature processing or rare elements.

Devices would not be limited to extreme cold, since the flexoelectric response persists up to the melting point. Designs would focus on geometry, because stronger curvature and sharper gradients usually drive larger signals in flexoelectric systems.

The ferroelectric surface layer at about -171°F raises interesting options for switching behavior in deep cold. It could enable memory-like responses in polar regions or high altitude labs, where a modest electric field flips the surface polarization while the interior remains nonpolar.

Electricity lessons from ice

Flexo-electricity turns uneven bending into electrical charge, even in a material long treated as electromechanically quiet under uniform pressure.

Ice now joins the small set of everyday materials proven to convert mechanical shape changes into measurable voltage. In storm physics, it emerges as a credible new factor working alongside well-known non-inductive charging processes.

Charge generated by bending fits naturally with the chaotic collisions of particles, linking lab findings to the electric dynamics of real clouds.

The study is published in the journal Nature Physics.

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