- Hidden tectonic fault near Portugal may explain Lisbon earthquakes Euronews.com
- Five-million-year-old fissure discovered off Portugal could explain Lisbon’s major earthquakes Yahoo News Canada
- New Paper Explains What Caused the 18th-Century Lisbon Earthquake Explorersweb »
- Dutch scientist finds possible cause of Europe’s deadliest earthquake; warns of repeat NL Times
Category: 7. Science
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Hidden tectonic fault near Portugal may explain Lisbon earthquakes – Euronews.com
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New solar flare images reveal the Sun’s hidden magnetic forces
Solar flares are powerful blasts of energy from the Sun that are able to wreak havoc on Earth’s magnetosphere when they’re pointed in the right direction.
Now, thanks to the clearest images ever taken of a flare, scientists are finally peeking into the Sun’s smallest hidden features.
On August 8, 2024, something remarkable happened: an X1.3-class flare erupted from the Sun’s surface. And this time, Earth had the perfect view.
Thanks to clear skies and ideal timing, astronomers captured the flare using the Daniel K. Inouye Solar Telescope in Hawaii.
It’s the largest solar telescope on Earth and has the kind of resolution that other telescopes can only dream about. What it revealed is changing the game.
Dangers of solar flares
Solar flares are dangerous bursts of energy that can mess with satellites, radio signals, power grids, and even airplane navigation.
These flares shoot out when magnetic field lines on the Sun snap and reconnect.
But understanding exactly how and where that happens has been tough – because the structures involved are incredibly small. But the new images will change all that.
What the telescope captured
During this flare, scientists saw something they had never been able to see before: ultra-thin coronal loops. These are delicate arcs of hot plasma that trace the Sun’s magnetic field lines.
They usually appear right before or during solar flares. The team measured the loops and found they were only about 30 miles (48 kilometers) wide – some as thin as 13 miles (21 kilometers).
For comparison, most solar loops we’ve seen before were closer to hundreds or even thousands of miles across.
Before this, scientists could only guess that loops might be this small. “We’re finally peering into the spatial scales we’ve been speculating about for years,” said Cole Tamburri, lead author of the study.
“This opens the door to studying not just their size, but their shapes, their evolution, and even the scales where magnetic reconnection – the engine behind flares – occurs.”
A high-resolution image of the flare from the Inouye Solar Telescope, taken on August 8, 2024, at 20:12 UT. The image is about 4 Earth-diameters on each side. Click image to enlarge. Credit: NSF/NSO/AURA Unexpected discovery
What’s astonishing is that the team wasn’t even searching for this. They were going to investigate the Sun’s chromosphere – the zone just above the surface – using a different device.
But the observations in the Visible Broadband Imager, which targets the H-alpha wavelength (a particular kind of red light at 656.28 nanometers), proved to be a treasure trove.
The images showed hundreds of these fine strands arching high above the Sun’s surface, tightly packed together.
Some were just barely wide enough to be picked up by the telescope, which can resolve details down to about 15 miles (24 kilometers). That’s more than twice the resolution of any other solar telescope in use.
“Knowing a telescope can theoretically do something is one thing,” said Maria Kazachenko, one of the study’s co-authors. “Actually watching it perform at that limit is exhilarating.”
The detail was so fine that scientists started to wonder if they were finally seeing the Sun’s building blocks.
Not just loops inside loops, but single, distinct magnetic threads. If that’s true, it could completely reshape how scientists model solar flares and the processes that drive them.
Earth and solar flares
There’s a practical side to all this, too. Solar storms can knock out technology that we depend on. GPS, power systems, and internet cables all feel the effects when the Sun sends out a powerful flare.
Better models based on real data help scientists make more accurate forecasts. If we can spot the tiniest structures forming before a flare, we might someday predict them earlier or with better precision.
“This is the first time the Inouye Solar Telescope has ever observed an X-class flare,” Tamburri said. “These flares are among the most energetic events our star produces, and we were fortunate to catch this one under perfect observing conditions.”
The telescope itself is run by the National Science Foundation’s National Solar Observatory (NSO), and this kind of discovery is exactly what it was built for.
Tamburri is part of a program that trains Ph.D. students to work with Inouye data so that more people in the field can learn how to use its powerful tools.
Solar images prove theories right
Theories have long predicted that magnetic loops on the Sun might be as thin as 6 miles (10 kilometers) wide, but no one could actually confirm it. Now, with Inouye, they can see it directly.
“Before Inouye, we could only imagine what this scale looked like,” Tamburri said. “Now we can see it directly. These are the smallest coronal loops ever imaged on the Sun.”
Even the look of the flare was striking. The image showed threadlike dark loops against a bright background, with two clear flare ribbons: one short and triangular, and one long and curved like an eyebrow.
“Even a casual viewer would immediately recognize the complexity,” Tamburri said. “It’s a landmark moment in solar science,” he added. “We’re finally seeing the Sun at the scales it works on.”
And that’s exactly the kind of vision scientists need to make sense of the star that runs our entire solar system.
The full study was published in the journal The Astrophysical Journal Letters.
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Solar panels installed in Switzerland 30 years ago still performing well, with material quality key to longevity
An analysis of six solar panel systems installed in Switzerland over 30 years ago shows they remain effective, with material quality emerging as the main factor determining their longevity.
Solar panel manufacturers typically guarantee their products for 25 to 30 years. While accelerated ageing tests performed in the lab support these estimates, they offer limited insight into their operational lifetime under real-world conditions.
Various studies have investigated how factors such as temperature, climate and mounting angle influence the lifetime of in-use solar panels. However, few have examined panels in extreme climates or systematically compared panels from different manufacturers.
A team based across Switzerland, Austria and Germany has now analysed the long-term performance of six photovoltaic systems installed across Switzerland between 1987 and 1993. Panel locations ranged from low-altitude domestic properties to solar panel farms to commercial buildings in mountainous regions, each experiencing different climates and mounting angles.
Panel performance declined by just 0.24% per year on average, about three times slower than literature values for such systems. Compared to reference studies, the researchers found that most of the tested panels retained over 80% of their initial power. ‘This [data] really shows that photovoltaics can last [longer than expected], and it’s an important message to the photovoltaic industry,’ says lead researcher Ebrar Özkalay at the University of Applied Science and Arts of Southern Switzerland
Altitude and climate influence the lifetime of panels, and the team found that the performance of panels at lower altitudes decreased at a faster rate. These panels often reach surface temperatures of up to 80°C, increasing thermal stress from daily and seasonal temperature variations.
Spectroscopic analyses of panel materials highlighted that encapsulants and adhesives degraded more at lower altitudes, leading to localised corrosion and reduced electrical conductivity. The researchers also noted that older panels lacking UV stabilisers degraded more quickly than other panels.
Felipe Angel, who studies the chemical synthesis, manufacture and characterisation of optoelectronic devices at the Research Centre for Nanotechnology and Advanced Materials in Chile , believes the findings will cause researchers to adjust accelerated stressing tests in the lab. ‘And that’s particularly critical for the emerging technologies where the stability is not that high.’
Modern photovoltaic systems often prioritise higher efficiencies and reduced costs, so use thinner and lower quality materials, but the team behind the study highlights that this strategy may compromise their long-term reliability. ‘The bill of materials – everything that goes into a panel – has a great influence on performance, even when made by the same company,’ adds Dirk Jordan, a photovoltaics expert at the National Renewable Energy Laboratory, US. ‘We can learn from these old panels to make future ones last, hopefully, as long.’
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James Webb Space Telescope observes planetary building blocks in Butterfly Nebula
Aug. 28 (UPI) — The James Webb Space Telescope has helped researchers learn new information about how the Earth may have been formed as it gives a deeper look into the Butterfly Nebula.
The telescope saw the creation of tiny planetary building blocks around a dead star, as it saw cosmic dust particles that create planets around young stars forming for the first time.
“For years, scientists have debated how cosmic dust forms in space. But now, with the help of the powerful James Webb Space Telescope, we may finally have a clearer picture,” said lead researcher Dr Mikako Matsuura, of Cardiff University.”We were able to see both cool gemstones formed in calm, long-lasting zones and fiery grime created in violent, fast-moving parts of space, all within a single object.”
The Butterfly Nebula is a white dwarf located 3,400 light-years away in the constellation of Scorpius the Scorpion.
A new image taken by the telescope showed in regions such as the torus of the Nebula planet show grains of dust aid in the beginning of the planet building process.
The size of the dust grains seen in the Butterfly Nebula suggests that it has been growing for a while.
The Monthly Notices of the Royal Astronomical Society reported on results of the JWST observations of the Butterfly Nebula on Aug 27.
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High-energy rocket fuel breakthrough boasts lighter, longer flights
A new high-energy compound has been synthesised with the potential to improve rocket fuel efficiency.
The University at Albany chemists synthesised the manganese diboride (MnB2) compound.
The compound releases more energy relative to its weight and volume than current fuels, which could make space flights more efficient and cost-effective.
MnB2 is over 20% more energetic by weight and 150% more energetic by volume than the aluminum presently used in solid rocket boosters.
The team says the high-energy compound only combusts upon contact with an ignition agent, such as kerosene.
This means a rocket can use less fuel to achieve the same performance, freeing up space for more mission-critical supplies and equipment.
“In rocket ships, space is at a premium. Every inch must be packed efficiently, and everything onboard needs to be as light as possible,” said Michael Yeung, Assistant Professor of Chemistry at the University at Albany, US.
The Yeung Lab’s arc melter synthesizes manganese diboride. Right: Molecular model of manganese diboride. (Photos by Brian Busher) Heated to an extreme level
Chemists have long theorized that diboride compounds possess unusual properties, but studying these properties was impossible because the compounds could not be created.
Thanks to new technology, scientists could successfully synthesize the unstable and highly energetic manganese diboride.
The synthesis process itself is an exercise in extreme chemistry.
Manganese and boron powders were pressed into a pellet, which was then heated to an extreme 3,000°C using an “arc melter.”
The resulting molten material is rapidly cooled, which locks in the unique atomic structure.
In this structure, a central manganese atom is unusually bonded to many other atoms, creating an overly crowded and strained configuration — much like a tightly coiled spring, ready to release energy.
“Successfully synthesizing pure manganese diboride is an exciting achievement in and of itself. And now, we can test it experimentally and discover new ways to put it to use,” said UAlbany PhD student Joseph Doane.
Computational modeling of structure
Further insights into the compound’s properties came from computational modeling led by PhD student Gregory John and computational chemist Alan Chen.
The models revealed a subtle “deformation” in the molecular structure. It showcased an atomic skew that directly accounts for the high potential energy stored within the material.
“Our model of the manganese diboride compound looks like a cross-section of an ice cream sandwich, where the outer cookies are made of a lattice structure comprised of interlocking hexagons,” said John.
“When you look closely, you can see that the hexagons aren’t perfectly symmetrical; they’re all a little skewed. This is what we call ‘deformation.’ We can use this measure as a proxy to determine the amount of energy stored in the material by measuring the extent of deformation. That skew is where the energy is stored,” John explained.
The versatile boron-based structure is also being explored for its potential in creating more durable catalytic converters for automobiles and as a catalyst for breaking down plastics.
This research highlights how scientific breakthroughs can happen unexpectedly.
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The James Webb Just Found Something Extremely Bizarre About the Mysterious Object Headed Into Our Inner Solar System
Our solar system’s latest and only third known interstellar visitor is becoming more fascinating by the week.
Spotted in early July, the object, dubbed 3I/ATLAS, is widely believed to be a comet. It’s traveling so fast that one look at its speed was enough to let astronomers know that it came from untold thousands of light years away. And it may even be older than our entire solar system.
Now, the James Webb Space Telescope has turned its mighty eye — specifically, its Near-Infrared Spectrograph instrument — towards the object, furnishing us with more details about its size and composition to back up what other observatories, including the Hubble Space Telescope, had found previously.
These findings were published in a new study by researchers at NASA and a host of universities, currently awaiting peer review. And one detail in it is especially tantalizing, as highlighted by Space.com: 3I/ATLAS has among the highest ever ratio of carbon dioxide to water ever observed in a comet. And it also appears that the ice entombed within the comet may have been exposed to higher levels of radiation than comes from our solar system, the authors found.
It’s a pristine sample of the greater cosmos delivered, serendipitously, right to our doorstep.
“Continued spectroscopic observations of interstellar objects have the potential to reveal crucial details on the physics and chemistry of planet formation in planetary systems other than our own,” reads the paper.
Comets are believed to form in large numbers during the formation of a planetary system, and can get ejected by gravitational encounters with larger objects, like planets, the authors explain. A mixture of rock, ice, and dust, these cosmic snowballs heat up as they near a star like our Sun, causing them to release a glowing cloud of gas called a coma, giving them their distinctive appearance.
The previous interstellar visitor, Borisov, was also believed to be a comet. Both have shown clear signs of cometary activity, such as possessing a coma. But Borisov was largely similar to the well-studied comets in our solar system, the authors wrote, save for unusual levels of carbon monoxide.
With its extreme imbalance of water and carbon, 3I/ATLAS appears to be a far more remarkable object. One scenario that the unprecedentedly high ratio of carbon suggests is that the comet first formed in the circumstellar cloud of gas and dust that surrounds a nascent star called a protoplanetary disk — specifically, near a region called the CO2 ice line, where temperatures are low enough that CO2 molecules can freeze into a solid.
Alternatively, something could be preventing the Sun’s warmth from reaching deep into the comet’s nucleus, suppressing the sublimation of water ice into water vapor, the authors speculated.
As we speak, 3I/ATLAS is storming towards the solar system’s center at over 138,000 miles per hour. Its speed, coupled with its trajectory, point to it originating from the center of the galaxy, possibly in a star system low in heavy elements. And to build up to such an incredible pace, it would have to be unimaginably ancient: perhaps 3 to 11 billion years old, previous research has estimated. The latest James Webb findings could help fill in more blanks about its origins and history.
3I/ATLAS is expected to reach perihelion, its closest distance to the Sun, around October 30 this year, coming within Mars’ orbit. Along the way, it’ll travel behind the Sun from our perspective — meaning for a while, it’ll be impossible to observe.
More on space: Scientist Says Mysterious Object Approaching Earth May Be Alien Artifact
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How a SpaceX mission could speed drug discoveries on Earth
This audio is auto-generated. Please let us know if you have feedback.A trip into outer space takes a toll on the human body, with low gravity atrophying muscles and eroding bones, causing astronauts to lose 1% of their mass every month.
Understanding how those conditions affect astronauts while also taking advantage of a low-gravity environment could help researchers make scientific progress much closer to home, not just to address specific diseases but to potentially create whole new classes of medicine.
“A lot of the changes that our bodies experience in microgravity mimic the conditions that our bodies see on Earth as we age, but it happens a lot faster,” said Heidi Parris, associate program scientist for NASA’s International Space Station Program, during a recent webinar.
For astronauts aboard the ISS, maintaining health requires effort, including daily two-hour workouts and careful nutrition. And while cell and tissue growth changes pose challenges for astronauts and mission support teams, they also offer opportunities for drug researchers looking to learn more about diseases.
SpaceX launched its CRS-33 cargo mission August 24 to the ISS carrying new research projects that scientists hope will speed drug discoveries and advances back on the ground.
Here are three unique benefits of microgravity that may accelerate the search for treatments to improve human health on Earth.
Enhanced growth of 3D structures
Arun Sharma, director of the Center for Space Medicine at Cedars-Sinai Medical Center, said that the low gravity environment of the ISS may help engineers grow 3-dimensional models called organoids, which are used to study diseases, drug response and toxicology. Induced pluripotent stem cells, adult somatic cells that can be reprogrammed to a stem-like state, form the basis for these models.
“Organoids are an extension of those induced pluripotent stem cells,” Sharma said. “They’re basically three-dimensional cell aggregates that are revolutionizing stem cell biology and biomedical research right now.”
Organoids can be grown here, but scientists suspect these spherical tissues may be of better quality if grown in microgravity, free from the compressing effects of gravity.
“After a month [on the ISS] they’ll be returned to Earth and the Cedars-Sinai laboratory for genetic and imaging analyses,” Sharma said. The hope is that they will be a structural improvement over their home-grown counterparts, potentially opening the door to mass production for a variety of critical applications.
Currently, Sharma uses organoids to study how cancer treatments affect the heart, but they can also be used to test efficacy or study conditions like heart disease. As their complexity grows, brain models could help gain a better understanding of neurodegenerative diseases such as Parkinson’s disease, Huntington’s disease and ALS.
Revealing hidden drivers of bone loss
Astronauts in microgravity lose bone 12 times faster than on Earth, inspiring scientists to take bone research into outer space. Dr. Abba Zubair, medical director and researcher at the Mayo Clinic in Jacksonville, Florida, said his team is seeking to better understand the mechanism behind bone loss and formation by taking their research to the ISS.
The human body continually breaks down and rebuilds bone through a process involving a complex network of mesenchymal stem cells, osteoblasts, osteocytes and osteoclasts. But Zubair suspects another factor may drive this process: inflammation triggered by a cell cytokine, interleukin-6, and understanding how that happens in low gravity could reveal new insights..
Their research aims to understand this mechanism and provide the foundation for drugs that might one day modulate this effect to keep bones healthy both in people on this planet and astronauts in space, he said.
Compressing drug development timelines
The accelerated degradation of bone, heart and muscle induced by microgravity offers an advantage in drug development, Sharma said.
“One thing we’re always interested in here on the ground, terrestrially, is ways to accelerate the timelines for drug discovery, for discovering new drugs that would be able to help improve cardiac conditioning, or perhaps treat diseases such as ALS or Parkinson’s,” he said.
These timelines typically take years on Earth, but using organoids to study these illnesses in space could accelerate that timeline.
“You can see those diseases potentially manifest faster in these organoids in space than you might be able to on the ground,” Sharma said, and speeding that process could also lead to faster drug discovery.
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A Burst of Subglacial Water Cracked the Greenland Ice Sheet
Greenland, despite its name, is largely blanketed in ice. And beneath that white expanse lies a world of hidden lakes. Researchers have now used satellite observations to infer that one such subglacial lake recently burst through the surface of the Greenland Ice Sheet, an unexpected and unprecedented event. By connecting this outburst with changes in the velocity and calving of a nearby glacier, the researchers helped to unravel how subglacial lakes affect ice sheet dynamics. These results were published in Nature Geoscience.
Researchers have known for decades that pools of liquid water exist beneath the Antarctic Ice Sheet, but scientific understanding of subglacial lakes in Greenland is much more nascent. “We first discovered them about 10 years ago,” said Mal McMillan, a polar scientist at Lancaster University and the Centre for Polar Observation and Modelling, both in the United Kingdom.
Subglacial lakes can exert a significant influence on an ice sheet. That’s because they affect how water drains from melting glaciers, a mechanism that in turn causes sea level rise, water freshening, and a host of other processes that affect local and global ecosystems.
McMillan is part of a team that recently studied an unusual subglacial lake beneath the Greenland Ice Sheet. The work was led by Jade Bowling, who was a graduate student of McMillan’s at the time; Bowling is now employed by Natural England.
Old, but Not Forgotten, Data
In the course of mining archival satellite observations of the height of the Greenland Ice Sheet, the team spotted something unusual in a 2014 dataset: An area of roughly 2 square kilometers had dropped in elevation by more than 80 meters (260 feet) between two satellite passes just 10 days apart. That deflation reflected something going on deep beneath the surface of the ice, the researchers surmised.
A subglacial lake that previously was situated at the interface between the ice and the underlying bedrock must have drained, said McMillan, leaving the ice above it hanging unsupported until it tumbled down. The team used the volume of the depression to estimate that roughly 90 million cubic meters (more than 3.1 billion cubic feet) of water had drained from the lake between subsequent satellite observations, making the event one of Greenland’s biggest subglacial floods in recorded history.
“We haven’t seen this before.”
Subglacial lakes routinely grow and shrink, however, so that observation by itself wasn’t surprising. What was truly unexpected lay nearby.
“We also saw an appearance, about a kilometer downstream, of a huge area of fractures and crevassing,” McMillan said. And beyond that lay 6 square kilometers (2.3 square miles)—an area roughly the size of lower Manhattan—that was unusually smooth.
The researchers concluded that after the subglacial lake drained, its waters likely encountered ice frozen to the underlying bedrock and were forced upward and through the surface of the ice. The water then flowed across the Greenland Ice Sheet before reentering the ice several kilometers downstream, leaving behind the polished, 6-square-kilometer expanse.
“This was unexpected,” said McMillan. “We haven’t seen this before.”
A Major Calving, a Slowing Glacier
It’s most likely that the floodwater traveled under northern Greenland’s Harder Glacier before finally flowing into the ocean.
Within the same 10-day period, Harder Glacier experienced its seventh-largest calving event in the past 3 decades. It’s impossible to know whether there’s a direct link between the subglacial lake draining and the calving, but it’s suggestive, said McMillan. “The calving event that happened at the same point is consistent with lots of water flooding out” from the glacier.
Using data from several Earth-observing satellites, scientists discovered that a huge subglacial flood beneath the Greenland Ice Sheet occurred with such force that it fractured the ice sheet, resulting in a vast quantity of meltwater bursting upward through the ice surface. Credit: ESA/CPOM/Planetary Visions “It’s like you riding on a waterslide versus a rockslide. You’re going to slide a lot faster on the waterslide.”
The team also found that Harder Glacier rapidly decelerated—3 times more quickly than normal—in 2014. That’s perhaps because the influx of water released by the draining lake carved channels in the ice that acted as conduits for subsequent meltwater, the team suggested. “When you have normal melting, it can just drain through these channels,” said McMillan. Less water in and around the glacier means less lubrication. “That’s potentially why the glacier slowed down.”
That reasoning makes sense, said Winnie Chu, a polar geophysicist at the Georgia Institute of Technology in Atlanta who was not involved in the research. “It’s like you riding on a waterslide versus a rockslide. You’re going to slide a lot faster on the waterslide.”
Just a One-Off?
In the future, McMillan and his colleagues hope to pinpoint similar events. “We don’t have a good understanding currently of whether it was a one-off,” he said.
Getting access to higher temporal resolution data will be important, McMillan added, because such observations would help researchers understand just how rapidly subglacial lakes are draining. Right now, it’s unclear whether this event occurred over the course of hours or days, because the satellite observations were separated by 10 days, McMillan said.
It’s also critical to dig into the mechanics of why the meltwater traveled vertically upward and ultimately made it to the surface of the ice sheet, Chu said. The mechanism that this paper is talking about is novel and not well reproduced in models, she added. “They need to explain a lot more about the physical mechanism.”
But something this investigation clearly shows is the value of digging through old datasets, said Chu. “They did a really good job combining tons and tons of observational data.”
—Katherine Kornei (@KatherineKornei), Science Writer
Citation: Kornei, K. (2025), A burst of subglacial water cracked the Greenland Ice Sheet, Eos, 106, https://doi.org/10.1029/2025EO250317. Published on 28 August 2025.
Text © 2025. The authors. CC BY-NC-ND 3.0
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Fossilized Micrometeorites Record Ancient CO2 Levels
Micrometeorites, unlike their larger brethren, rarely get a spotlight at museums. But there’s plenty to learn from these extraterrestrial particles, despite the largest of them measuring just millimeters across.
Nearly 50 tons of extraterrestrial material fall on Earth every day, and the majority of that cosmic detritus is minuscule. Micrometeorites are, by definition, smaller than 2 millimeters in diameter, and they’re ubiquitous, said Fabian Zahnow, an isotope geochemist at Ruhr-Universität Bochum in Germany. “You can basically find them everywhere.”
Researchers recently analyzed fossilized micrometeorites that fell to Earth millions of years ago. They extracted whiffs of atmospheric oxygen incorporated into the particles and showed that carbon dioxide (CO2) levels during the Miocene and Cretaceous did not differ wildly from modern-day values. The results were published in Communications Earth and Environment.
Extraterrestrial Needles in Rocky Haystacks
Newly fallen micrometeorites can be swept from rooftops and dredged from the bottoms of lakes.
Zahnow and his collaborators, however, opted to turn back the clock: The team analyzed a cadre of micrometeorites that fell to Earth millions of years ago and have since been fossilized. The team sifted through more than a hundred kilograms of sedimentary rocks, mostly unearthed in Europe, to discover 92 micrometeorites rich in iron. They added eight other iron-dominated micrometeorites from personal collections to bring their sample to 100 specimens.
Metal-rich micrometeorites such as these are special, said Zahnow, because they function like atmospheric time capsules. As they hurtle through the upper atmosphere on their way to Earth, they melt and oxidize, meaning that atmospheric oxygen gets incorporated into their otherwise oxygen-free makeup.
“When we extract them from the rock record, we have our oxygen, in the best case, purely from the Earth’s atmosphere,” said Zahnow.
Ancient Carbon Dioxide Levels
And that oxygen holds secrets about the past. It turns out that atmospheric oxygen isotope ratios—that is, the relative concentrations of the three isotopes of oxygen, 16O, 17O, and 18O—correlate with the amount of photosynthesis occurring and how much CO2 is present at the time. That fact, paired with model simulations of ancient photosynthesis, allowed Zahnow and his colleagues to infer long-ago atmospheric CO2 concentrations.
“The story of the atmosphere is the story of life on Earth.”
Reconstructing Earth’s atmosphere as it was millions of years ago is important because atmospheric gases affect our planet so fundamentally, said Matt Genge, a planetary scientist at Imperial College London not involved in the work. “The story of the atmosphere is the story of life on Earth.”
But Zahnow and his collaborators first had to make sure the oxygen in their micrometeorites hadn’t been contaminated. Terrestrial water, with its own unique oxygen isotope ratios, can seep into micrometeorites that would otherwise reflect atmospheric oxygen isotope ratios from long ago. That’s a common problem, said Zahnow, given the ubiquity of water on Earth. “There’s always some water present.”
The team found that the presence of manganese in their micrometeorites was a tip-off that contamination had occurred. “Extraterrestrial metal has basically no manganese,” said Zahnow. “Manganese is really a tracer for alteration.”
Unfortunately, the vast majority of the researchers’ micrometeorites contained measurable quantities of manganese. In the end, Zahnow and his collaborators deemed that only four of their micrometeorites were uncontaminated.
Those micrometeorites, which fell to Earth during the Miocene (9 million years ago) and the Late Cretaceous (87 million years ago), suggested that CO2 levels during those time periods were, on average, roughly 250–300 parts per million. That’s a bit lower than modern-day levels, which hover around 420 parts per million.
“What we really hoped for was to get pristine micrometeorites from periods where the reconstructions say really high concentrations.”
The team’s findings are consistent with values suggested previously, said Genge, but unfortunately, the team’s numbers just aren’t precise enough to conclude anything meaningful. “You have a really huge uncertainty,” he said.
The team’s methods are solid, however, said Genge, and the researchers made a valiant effort to measure what are truly faint whiffs of ancient oxygen. “It’s a brave attempt.”
In the future, it would be valuable to collect a larger number of pristine micrometeorites dating to time periods when model reconstructions suggest anomalously high CO2 levels, said Zahnow. “What we really hoped for was to get pristine micrometeorites from periods where the reconstructions say really high concentrations.”
Confirming, with data, whether such time periods, such as the Triassic, truly had off-the-charts CO2 levels would be valuable for understanding how life on Earth responded to such an abundance of CO2.
—Katherine Kornei (@KatherineKornei), Science Writer
Citation: Kornei, K. (2025), Fossilized micrometeorites record ancient CO2 levels, Eos, 106, https://doi.org/10.1029/2025EO250319. Published on 28 August 2025.
Text © 2025. The authors. CC BY-NC-ND 3.0
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When spider scientists went into a Taiwanese forest at night, they discovered a deadly trap
Researchers in Taiwan have observed sheet web spiders (Psechrus clavis) capturing fireflies and leaving them glowing in their webs for up to an hour. This unusual tactic turns the fireflies’ mating signals into a deadly lure, with other insects attracted to the light before becoming trapped themselves.
Keen to find out more about the hunting strategy, scientists from Tunghai University devised a field experiment in the Xitou Nature Education Area – a mountainous forest park in the heart of the country.
Here, under the cover of darkness, they placed LEDs designed to mimic firefly light in some spider webs, while leaving other webs empty as controls.
The results, published in the Journal of Animal Ecology, show that webs with lights attracted three times more prey than unlit webs, and in the case of fireflies specifically, capture rates increased tenfold.
A sheet web spider with fireflies caught in web. Credit: Tunghai University “Our findings highlight a previously undocumented interaction where firefly signals, intended for sexual communication, are also beneficial to spiders,” explains Dr I-Min Tso, lead author of the study.
“This study sheds new light on the ways that nocturnal sit-and-wait predators can rise to the challenges of attracting prey and provides a unique perspective on the complexity of predator-prey interactions.”
The study also revealed that most of the glowing fireflies caught in webs were males, likely mistaking the bioluminescence of trapped individuals for potential mates.
Video footage captured during the research shows spiders treating prey differently: moths were eaten immediately, while fireflies were left alive, continuing to emit their mating signals.
“Handling prey in different ways suggests that the spider can use some kind of cue to distinguish between the prey species they capture and determine an appropriate response,” says Dr Tso.
“We speculate that it is probably the bioluminescent signals of the fireflies that are used to identify fireflies enabling spiders to adjust their prey handling behaviour accordingly.”
Video shows a spider capturing a firefly. Credit: Tunghai University Unlike anglerfish and other predators that invest energy in producing their own lures, the sheet web spider appears to save energy by outsourcing this function to its prey.
The researchers suggest this adaptation may have evolved as a cost-effective strategy for survival in subtropical forests of East Asia, where both the spider and its main prey, the winter firefly (Diaphanes lampyroides), are found.
The study notes that although the LED mimics were a close match to real fireflies, future experiments using live insects would provide stronger evidence of this remarkable strategy.
Top image: fireflies in Taiwanese forest. Credit: Getty
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