Neanderthals Mysteriously Collected Horned Skulls in a Cave, But Why?

22 Feb. 2026, By M. STARR

https://www.sciencealert.com/neanderthals-mysteriously-collected-horned-skulls-in-a-cave-but-why

Some of the skulls found in the cave. 

(Villaescusa et al., Archaeol. Anthropol. Sci., 2026)

A new investigation of ancient horned animal skulls found in Spain's Des-Cubierta Cave deepens the mystery of when and why Neanderthals put them there.

According to multiple lines of evidence, the skulls weren't all placed there at the same time but were likely carried into a narrow gallery repeatedly over a prolonged period during the late Middle Paleolithic, between around 70,000 and 50,000 years ago.

Excavation of the cave began in 2009, and one of the rock layers caught archaeologists' attention for a large assemblage of Mousterian stone tools, a culture primarily associated with Neanderthals in Europe.

But it wasn't just tools; there was also an unusual assemblage of animal remains, overwhelmingly composed of skulls.

Researchers cataloged the top parts of the skulls of at least 35 individual animals, including 28 bovines, five deer, and two rhinoceroses. Most of the rest of the skeletons, such as jawbones, limbs, and even cheekbones, are absent.

The deliberate accumulation of animal crania is pretty rare in the archaeological record. A team led by archaeologist Lucía Villaescusa of the University of Alcalá in Spain wanted to know if the site itself could yield any clues about the way these skulls were placed.

They studied multiple lines of evidence, including the spatial distribution of geological debris and archaeological artifacts in the deposit; reassembly of the fragmented bones; and the level of preservation of the bones.

Their results showed that rockfall first introduced a cone of debris into the gallery. It was after this rockfall that Neanderthals began to bring in animal skulls, placing them in the cave during separate phases of activity.

The timeframe of this activity is unclear, but the separation between deposits makes it clear that it was not a one-and-done instance of skull collection.

As with so many ancient human and Neanderthal activities, it's likely we'll never know why the Neanderthals of Des-Cubierta had a repeated tradition of putting crania in a cave, but the repeated pattern suggests a structured practice that offers a rare glimpse into the possible symbolic lives of our ancient relatives.

"The integration of geological, spatial, and taphonomic data demonstrates that the accumulation of large herbivore crania was not a single depositional event, but rather the result of repeated episodes embedded within a long-term process of gallery use," the researchers write.

"This sustained and reiterated behaviour highlights the structured and transmitted nature of this practice, adding a significant piece to the broader discussion on the complexity and symbolic potential of Neanderthal cultural expressions."

The birth of modern Man

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Men Lose Their Y Chromosome With Age. We Finally Know The Cost.

22 Feb. 2026, By J. GRAVES, THE CONVERSATION

https://www.sciencealert.com/men-lose-their-y-chromosome-with-age-we-finally-know-the-cost

(Cavan Images/Getty Images)

Men tend to lose the Y chromosome from their cells as they age. But because the Y bears few genes other than for male determination, it was thought this loss would not affect health.

But evidence has mounted over the past few years that when people who have a Y chromosome lose it, the loss is associated with serious diseases throughout the body, contributing to a shorter lifespan.

Loss of the Y in older men

New techniques to detect Y chromosome genes show frequent loss of the Y in tissues of older men. The increase with age is clear: 40% of 60-year-old men show loss of Y, but 57% of 90-year-olds. Environmental factors such as smoking and exposure to carcinogens also play a role.

Loss of Y occurs only in some cells, and their descendants never get it back. This creates a mosaic of cells with and without a Y in the body. Y-less cells grow faster than normal cells in culture, suggesting they may have an advantage in the body – and in tumours.

The Y chromosome is particularly prone to mistakes during cell division – it can be left behind in a little bag of membrane that gets lost. So we would expect that tissues with rapidly dividing cells would suffer more from loss of Y.

Why should loss of the gene-poor Y matter?

The human Y is an odd little chromosome, bearing only 51 protein-coding genes (not counting multiple copies), compared with the thousands on other chromosomes. It plays crucial roles in sex determination and sperm function, but was not thought to do much else.

Is the Y chromosome vanishing in men? Read our story on the scientific debate. 

(Dmitry Bayer/Getty Images)



The Y chromosome is frequently lost when cells are cultured in the lab. It is the only chromosome that can be lost without killing the cell. This suggests no specific functions encoded by Y genes are necessary for cellular growth and function.

Indeed, males of some marsupial species jettison the Y chromosome early in their development, and evolution seems to be rapidly dispensing with it. In mammals, the Y has been degrading for 150 million years and has already been lost and replaced in some rodents.

So the loss of Y in body tissue late in life should surely not be a drama.

Association of loss of Y with health problems

Despite its apparent uselessness to most cells in the body, evidence is accumulating that loss of Y is associated with severe health conditions, including cardiovascular and neurodegenerative diseases and cancer.

Loss of Y frequency in kidney cells is associated with kidney disease.

Several studies now show a relationship between loss of Y and cardiac disease. For instance, a very large German study found men over 60 with high frequencies of loss of Y had an increased risk of heart attacks.

Loss of Y has also been linked to death from COVID, which might explain the sex difference in mortality. A tenfold higher frequency of loss of Y has been found in Alzheimer's disease patients.

Several studies have documented associations of loss of Y with various cancers in men. It is also associated with a poorer outcome for those who do have cancer. Loss of Y is common in cancer cells themselves, among other chromosome anomalies.

Does loss of Y cause disease and mortality in older men?

Figuring out what causes the links between loss of Y and health problems is difficult. They might occur because health problems cause loss of Y, or perhaps a third factor might cause both.

Even strong associations can't prove causation. The association with kidney or heart disease could result from rapid cell division during organ repair, for instance.

Cancer associations might reflect a genetic predisposition for genome instability. Indeed, whole genome association studies show loss of Y frequency is about one-third genetic, involving 150 identified genes largely involved in cell cycle regulation and cancer susceptibility.

However, one mouse study points to a direct effect. Researchers transplanted Y-deficient blood cells into irradiated mice, which then displayed increased frequencies of age-related pathologies including poorer cardiac function and subsequent heart failure.

Similarly, loss of Y from cancer cells seems to affect cell growth and malignancy directly, possibly driving eye melanoma, which is more frequent in men.

Role of the Y in body cells

The clinical effects of loss of Y suggest the Y chromosome has important functions in body cells. But given how few genes it hosts, how?

The male-determining SRY gene found on the Y is expressed widely in the body. But the only effect ascribed to its activity in the brain is complicity in causing Parkinson's disease. And four genes essential for making sperm are active only in the testis.

But among the other 46 genes on the Y, several are widely expressed and have essential functions in gene activity and regulation. Several are known cancer suppressors.

These genes all have copies on the X chromosome, so both males and females have two copies. It may be that the absence of a second copy in Y-less cells causes some kind of dysregulation.

As well as these protein-coding genes, the Y contains many non-coding genes. These are transcribed into RNA molecules, but never translated into proteins. At least some of these non-coding genes seem to control the function of other genes.

This might explain why the Y chromosome can affect the activity of genes on many other chromosomes. Loss of Y affects expression of some genes in the cells that make blood cells, as well as others that regulate immune function. It may also indirectly affect differentiation of blood cell types and heart function.

The DNA of the human Y was only fully sequenced a couple of years ago – so in time we may track down how particular genes cause these negative health effects.

The Life of Earth

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Scientists Reveal the Brain’s Hidden Map of Thought

BY OHIO STATE U., FEB. 17, 2026

https://scitechdaily.com/scientists-reveal-the-brains-hidden-map-of-thought/

Researchers have demonstrated that the brain’s connection patterns can predict the function of each region across a wide range of cognitive tasks. This discovery strengthens the idea that how the brain is wired determines how it works. 

Credit: SciTechDaily.com

The brain’s wiring forms a unique fingerprint that reveals how we think, remember, and make decisions.

A new study offers the strongest evidence so far that the way different parts of the brain are wired together can reveal what each region is designed to do. By analyzing large-scale brain data, researchers found that connection patterns themselves hold clues about specialized functions across the brain.

Earlier work had linked connectivity to individual abilities such as perception or social behavior. This new research expands that view, examining how connectivity relates to many mental functions across the entire brain. Lead author Kelly Hiersche, a doctoral student in psychology at The Ohio State University, described the approach as providing a “bird’s eye view” of how brain structure supports a wide range of cognitive abilities.

“We found evidence suggesting that connectivity is a fundamental organizational principle governing brain function, which has implications for understanding what happens when things go wrong in the brain,” Hiersche said.

The Brain’s Unique Connectivity Fingerprints

The researchers report that each brain region carries its own distinctive “connectivity fingerprint.” These fingerprints reflect how a region is linked to other parts of the brain and correspond to the mental tasks it performs.

“Just like how everyone’s fingerprint is unique, we find that different brain regions have uniquely identifying connectivity fingerprints based on what mental function they perform,” said co-author Zeynep Saygin, associate professor of psychology at Ohio State.

Senior author David Osher, assistant professor of psychology at Ohio State, explained that scientists can use these fingerprints to predict what a region does. “Our findings help us understand the connectivity pattern that makes a language area unique, for example, and what makes it different from adjacent areas in the brain,” Osher said.

The results were published in the journal Network Neuroscience.

Combining MRI Brain Scans and Cognitive Maps

To conduct the study, the team used data from the Human Connectome Project, which includes MRI scans from 1,018 participants. These scans capture how brain regions are connected.

The researchers also relied on NeuroQuery, an online meta-analysis tool that generates brain maps for specific cognitive processes. NeuroQuery estimates how the brain activates across 33 mental functions, including speech, decision-making, listening to music, and face perception. Hiersche and her colleagues then developed computational models that linked the connectivity data from MRI scans with the activity patterns identified by NeuroQuery.

Connectivity Predicts Brain Activity

The findings revealed a strong and reliable relationship between connectivity patterns and brain activation across nearly all regions and cognitive domains. Specific wiring patterns could predict whether a region would be active—or inactive—during different tasks, from recognizing a face to having a conversation or making a choice.

“It supports a broadly held hypothesis among neuroscientists, that brain connectivity determines brain function, but this has not been explicitly shown until now, and not across such a large breadth of cognitive domains,” Osher said.

Stronger Links in Higher Level Skills

Although the connection between wiring and function appeared throughout the brain, the tightest relationships were found in areas responsible for higher-level abilities such as executive function and memory. These regions showed stronger connectivity function alignment than areas involved in sensory processing or social skills, Hiersche said.

“These higher-level skills take many years to develop in people, much longer than sensory or social skills,” she said.

“It may be that as you continually use these regions of the brain for them to develop, it results in this very tight link between connectivity and function for these higher-order skills.”

A Baseline for Understanding Brain Disorders

Because the study examined the whole brain at once, it provides a reference point for how healthy young adult brains are typically organized, Hiersche said.

Researchers can now compare this baseline to brain data from people with neurological or psychiatric conditions to better understand how connectivity and function differ in those cases.

“Knowing that connectivity is a general organizational principle of brain function across the entire brain provides a foundation for future work in this area.”

The Life of Earth

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The Southern Indian Ocean Is Losing Salt at an “Astonishing” Rate

BY U. OF COLORADO AT BOULDER, FEB. 19, 2026

https://scitechdaily.com/the-southern-indian-ocean-is-losing-salt-at-an-astonishing-rate/

The waters off Western Australia are becoming dramatically less salty and the cause traces back to climate-driven shifts in global winds. Scientists warn that this quiet transformation could ripple through ocean circulation and marine life worldwide. 

Credit: SciTechDaily.com

A vast region of the Southern Indian Ocean is freshening at an unprecedented pace.

Ocean water is not just “wet.” Its saltiness helps determine how seawater stacks up in layers, how currents move heat around the planet, and how easily nutrients can reach the sunlit surface where much of marine life begins. That is why scientists are paying close attention to a startling shift now unfolding off Western Australia: the Southern Indian Ocean there is freshening fast.

According to a study published in Nature Climate Change, researchers from the University of Colorado Boulder report that rising global temperatures over the past 60 years have altered major wind patterns and ocean currents. These shifts are funneling increasing amounts of freshwater into the Southern Indian Ocean. The researchers warn that this trend could reshape how the ocean and atmosphere interact, interfere with large circulation systems that regulate climate worldwide, and place added stress on marine ecosystems.

“We’re seeing a large-scale shift of how freshwater moves through the ocean,” said Weiqing Han, professor in the Department of Atmospheric and Oceanic Sciences. “It’s happening in a region that plays a key role in global ocean circulation.”
The Indo-Pacific Freshwater Pool

Much of the incoming freshwater can be traced back to a huge tropical region where surface waters are naturally diluted by frequent rain. This zone, stretching from the eastern Indian Ocean across to the western Pacific in the Northern Hemisphere tropics, stays relatively fresh because rainfall is high while evaporation is comparatively low. Scientists often call it the Indo Pacific freshwater pool.

That pool is not isolated. It connects to the thermohaline circulation, a global current system sometimes described as a conveyor belt because it moves heat, salt, and freshwater between ocean basins. Warm surface waters from the Indo Pacific feed into pathways that ultimately influence conditions in the Atlantic. In the North Atlantic, that transported water cools, becomes denser, sinks, and then returns southward at depth before eventually flowing back toward the Indian and Pacific Oceans. Small shifts in salinity can matter here because salt helps set seawater density, and density helps power the sinking and spreading that keep the system moving.

The waters off Australia’s southwest have typically been dry at the surface, with evaporation outpacing rainfall. That pattern has historically favored higher salinity. But long-term observations show that the balance is changing.

Han’s team estimates that the area covered by salty seawater in this Southern Indian Ocean region has shrunk by about 30% over the past 60 years. They describe it as the fastest freshening seen anywhere in the Southern Hemisphere.

“This freshening is equivalent to adding about 60% of Lake Tahoe’s worth of freshwater to the region every year,” said first author Gengxin Chen, visiting scholar in the Department of Atmospheric and Oceanic Sciences and senior scientist at the Chinese Academy of Sciences’ South China Sea Institute of Oceanology. “To put that into perspective, the amount of freshwater flowing into this ocean area is enough to supply the entire U.S. population with drinking water for more than 380 years,” he said.
Climate-Driven Wind Shifts

The researchers found that the growing influx of freshwater cannot be explained by local rainfall. By analyzing observational records alongside computer simulations, they concluded that global warming is reshaping surface wind patterns across the Indian and tropical Pacific Oceans. These altered winds are steering ocean currents in ways that transport more freshwater from the Indo-Pacific freshwater pool into the Southern Indian Ocean.

As salt levels drop, seawater becomes less dense. Fresher water tends to remain above saltier, heavier water, increasing the separation between surface and deep layers. This enhanced layering limits vertical mixing, the process that normally allows surface water to sink and deeper water to rise, distributing heat and nutrients throughout the ocean.

Previous studies have suggested that climate change could slow part of the thermohaline circulation, as melting from the Greenland Ice Sheet and Arctic sea ice adds freshwater to the North Atlantic, disrupting the salinity balance needed for the conveyor belt to keep moving. The expansion of the freshwater pool could further influence this system by transporting fresher water into the Atlantic.

Weaker vertical mixing could also harm marine life. When nutrient-rich water from the depths does not reach the sunlit surface, organisms in upper layers have fewer resources to survive. At the same time, reduced mixing traps excess heat near the surface, raising temperatures further for species already coping with warming oceans.

“Salinity changes could affect plankton and sea grass. These are the foundation of the marine food web. Changes in them could have far-reaching impact on the biodiversity in our oceans,” Chen said.

The Life of Earth

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'Freak of Nature': Scientists Think Greenland's Ice Is Churning Like Molten Rock

21 Feb. 2026, By M. STARR

https://www.sciencealert.com/freak-of-nature-scientists-think-greenlands-ice-is-churning-like-molten-rock

(Arctic-Images/Stone/Getty Images)

Deep inside the Greenland ice sheet, radar images have revealed strange, plume-like structures distorting the layering deposited over eons.

Now, more than a decade after their discovery, scientists think they have figured out what causes these structures, and it's a real hum-dinger. According to modeling, the plumes are a striking match for convection: the roiling upward transport of heat more commonly linked to the fiery, molten rock churning beneath Earth's crust.

"Finding that thermal convection can happen within an ice sheet goes slightly against our intuition and expectations. Ice is at least a million times softer than the Earth's mantle, though, so the physics just work out," says glaciologist Robert Law of the University of Bergen in Norway.

"It's like an exciting freak of nature."

Example plume structures from northern Greenland, mapped from radar surveys.

 (Law et al., The Cryosphere, 2026)

The Greenland ice sheet, which covers 80 percent of the island, is one of our planet's biggest reservoirs of frozen water, and is forecast to play a major role in rising sea levels as it melts into the ocean. Understanding the physics inside it is vital for predicting how the ice sheet will change over time.

This is why scientists use ice-penetrating radar. Radio waves pass through the ice and reflect back differently as they encounter internal layers – snow that fell long ago and was compacted into ice as more snow piled on top. Each of these layers has its own characteristics – slightly different acidity levels, for example, and variations in dust, ash, and chemical content.

In a 2014 paper, scientists described strange structures these radar images had revealed deep inside the ice in northern Greenland. These large, upward-buckling features were unrelated to the topography of the bedrock below, presenting a puzzle researchers have been trying to solve ever since.

https://www.youtube.com/watch?v=-JdzA6fC91s&t=1s

Previous efforts suggested that mechanisms such as glacial meltwater freezing onto the underside of the ice sheet, or migrating slippery spots, may be responsible for the structures. One idea that had not been tested, however, was that thermal convection may take place within ice sheets.

To test the idea, Law and his colleagues turned to computer modeling. They built a simplified digital slice of the Greenland ice sheet and asked a simple question: If the base of the ice is warmed from below, could convection form structures that match what radar sees?

They used a geodynamics modeling package normally used to simulate convection in Earth's mantle to model a slab of ice 2.5 kilometers (1.6 miles) thick. They tweaked variables such as snowfall rate, ice thickness, how soft the ice is, and how fast the ice moves on the surface.

Under the right conditions, the model began producing plume-like upwellings – rising columns of ice that folded the overlying layers into shapes strikingly similar to those seen in radar images.

In the model, plumes only formed when the ice near the base was warmer and significantly softer than standard assumptions allow, suggesting that if convection is responsible, the real ice at the base of northern Greenland's ice sheet may also be softer than previously thought.

Meanwhile, the heat required to produce these convection upwellings in the model was consistent with the heat continuously flowing from Earth, generated by the radioactive decay of elements within the crust and by residual heat from Earth's formation as it gradually cools over billions of years.

This effect is tiny, but over time, and under a giant slab of insulating material, it could build up enough to warm and soften the ice above it.

"We typically think of ice as a solid material, so the discovery that parts of the Greenland ice sheet actually undergo thermal convection, resembling a boiling pot of pasta, is as wild as it is fascinating," says climatologist Andreas Born of the University of Bergen.

Now, that doesn't mean the ice is slushy. It's still solid ice, flowing only on timescales of thousands of years. It also doesn't necessarily mean that it will melt faster. Further investigation into the physics of ice, and the effects of convection on the evolution of the ice sheet, is required to determine what this means for the future.

"Greenland and its nature is truly special. The ice sheet there is over one thousand years old, and it's the only ice sheet on Earth to have a culture and permanent population at its margins," Law says.

"The more we learn about the hidden processes inside the ice, the better prepared we'll be for the changes coming to coastlines around the world."

The Life of Earth

https://chuckincardinal.blogspot.com/

Something Strange Altered Earth's Magnetic Field 40 Million Years Ago

21 Feb. 2026,By D. NIELD

https://www.sciencealert.com/something-strange-altered-earths-magnetic-field-40-million-years-ago

(Mark Garlick/Science Photo Library/Getty Images)

Researchers have identified a period of sluggish magnetic field flipping for planet Earth, some 40 million years ago – raising big questions about how long these reversals actually take, and how we might be affected by the next one.

Magnetic field flips are thought to happen fairly regularly, as far as geological timescales go. There have been some 540 reversals across the last 170 million years, and it seems they've been happening for billions of years.

But something was different 40 million years ago. One transition around this time took 18,000 years, and another took at least 70,000 years, the international team of researchers found, which is far longer than the typical timespan of 10,000 years or so that scientists think is the norm.

"This finding unveiled an extraordinarily prolonged reversal process, challenging conventional understanding and leaving us genuinely astonished," writes lead author and paleomagnetist Yuhji Yamamoto from Kochi University in Japan.

"The variability in reversal duration revealed by this study reflects the intrinsic dynamical properties of the Earth's geodynamo, and it provides empirical evidence that geomagnetic reversals can last significantly longer than the widely assumed 10,000-year duration."

The team analyzed a sediment core extracted from a location off the coast of Newfoundland in the North Atlantic. The magnetic signals inside these cores, locked to tiny crystals, reveal the direction of Earth's magnetic field over vast time periods.

Yuhji Yamamoto studying a drilling core. 

(Peter Lippert)



In this case, the researchers looked closely at a specific layer measuring 8 meters (a little over 26 feet) top to bottom, representing part of the Eocene era. There was a clear shift in polarity, but across an unexpectedly large section of the sediment core.


Two magnetic field flips were discovered, one lasting around 18,000 years, and another lasting 70,000 years. Computer modeling suggested events like these could potentially stretch across 130,000 years in some cases – though that's never been seen in the geological record.

https://www.youtube.com/watch?v=IgouMVdqLDI&t=5s

These magnetic field flips are driven by shifts in Earth's liquid iron and nickel outer core, around 2,200 kilometers (1,367 miles) thick. While this outer core is always in flux, it occasionally becomes unstable enough that the magnetic poles change position.

The planet doesn't tip over, but magnetic north becomes magnetic south, and vice versa – your compass would eventually point in the opposite direction, after tens of thousands of years of being incredibly confused.

Not only did these newly identified flips take a long time, but they were messier and more variable than the researchers expected. There were multiple 'rebounds' where the magnetic field seemed unsure about which direction to travel in, matching findings from our planet's most recent flip – the Brunhes-Matuyama reversal.

"The occurrence of multiple rebounds is not unprecedented: this behaviour is also reported for the Brunhes-Matuyama reversal," write the researchers in their published paper.

"We suggest that it may be more common and that polarity reversals are inherently complex, if not somewhat chaotic, events."

The Brunhes-Matuyama reversal, which happened around 775,000 years ago, backs up the new findings. A study from 2019 found that the flip took 22,000 years to complete – so drawn-out reversals may be the rule, rather than the exception.

When the next one happens, we need to be ready. One of the consequences of a magnetic field reversal is that our planet gets far less protection from the radiation and geomagnetic activity beaming down from space.

If that exposure is going to last tens of thousands of years longer than previously thought, we need to know about it. It has the potential to disrupt everything from animal species to climate systems – though more research will be needed to know the precise effects.

"It's basically saying we are exposing higher latitudes in particular, but also the entire planet, to greater rates and greater durations of this cosmic radiation," says paleomagnetist Peter Lippert from the University of Utah.

"Therefore, it's logical to expect that there would be higher rates of genetic mutation. There could be atmospheric erosion."

The Life of Earth

https://chuckincardinal.blogspot.com/

Astonishing Spinosaur Unearthed in The Sahara Is Unlike Any Seen Before

20 Feb. 2026, By J. COCKERILL

https://www.sciencealert.com/astonishing-spinosaur-unearthed-in-the-sahara-is-unlike-any-seen-before

Paleontologist Paul Sereno with the reconstructed Spinosaurus mirabilis skull. (Keith Ladzinski/University of Chicago)


A new Spinosaurus species has been unearthed from the Saharan desert, and its skull bears a magnificent crest never seen before on this kind of dinosaur.

Paleontologists have named it Spinosaurus mirabilis, meaning 'wonderful spine lizard'. We heartily agree.

Paleoartist rendering of Spinosaurus mirabilis eating a coelacanth. 

(Dani Navarro)



The discovery reveals more than just the dinosaur's beauty, however. Spinosaurus have mostly been found in coastal deposits, while this new specimen hails from deep inland in Niger, hundreds of kilometers from any ocean.

Even the paleontology team, led by Paul Sereno of the University of Chicago, was caught off guard.

"This find was so sudden and amazing, it was really emotional for our team," Sereno says.


"I'll forever cherish the moment in camp when we crowded around a laptop to look at the new species for the first time… One member of our team generated 3D digital models of the bones we found to assemble the skull – on solar power in the middle of the Sahara. That's when the significance of the discovery really registered."

With its spiky, interlocking teeth reminiscent of modern crocodiles, and its proximity to long-necked dinosaurs buried in nearby river sediments, Sereno and team think this Spinosaurus might have led a semi-aquatic lifestyle amidst a forested habitat.

"I envision this dinosaur as a kind of 'hell heron' that had no problem wading on its sturdy legs into two meters of water but probably spent most of its time stalking shallower traps for the many large fish of the day," Sereno says.

The scimitar-shaped crest sure is handsome, but exactly what purpose it served remains a mystery. The team suspect it was once sheathed in keratin – perhaps brightly colored, like a toucan's bill – to create a kind of visual display.

The Life of Earth

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This Comet Mysteriously Reversed Its Spin After Passing The Sun, But Why?

20 Feb. 2026, By M. STARR

https://www.sciencealert.com/this-comet-mysteriously-reversed-its-spin-after-passing-the-sun-but-why

Comet 41P photographed in March 2017. 

(Kees Scherer/Flickr, CC0)

A comet whizzing through the Solar System has astonished scientists by doing something they had never seen before.

In early 2017, comet 41P/Tuttle-Giacobini-Kresák made its 5.4-year close approach to the Sun, or perihelion.

As it did so, its spin appeared to slow down to a complete halt, before likely starting up again in the opposite direction, according to astronomer David Jewitt of the University of California, Los Angeles.

The reversal itself isn't the crazy part; changes in cometary spin are known to happen sometimes as these icy objects draw near to the Sun. Rather, it's how quickly and dramatically the reversal occurred.

https://www.youtube.com/watch?v=oe-d9RxLLaM&t=3s

"The previous record for a comet spindown went to 103P/Hartley 2, which slowed its rotation from 17 to 19 hours over 90 days," said astronomer Dennis Bodewits of the University of Maryland, describing the slowdown phase in 2018.

"By contrast, 41P spun down by more than 10 times as much in just 60 days, so both the extent and the rate of this change is something we've never seen before."

The sequence of events is as follows. Observations taken in March 2017 showed that 41P's rotation period was about 20 hours. By May, the rotation had slowed to more than double that length, with one rotation every 53 hours or so.

By December, however, something really weird had happened. The rotation period of the comet had shortened to 14.4 hours – a change, Jewitt believes, that can best be explained if its rotation had slowed to a complete stop sometime around June 2017 and then changed direction.

This is actually fairly easy to explain, in theory. Comets are clumpy agglomerations of rock and ice that spend most of their orbital periods just trucking along. However, as they get closer to the Sun, the ice in their bodies starts to transition directly into gas, a process called sublimation.

Jets and geysers burst forth, spraying vapor out into space. Each of these jets imparts a torque on the cometary nucleus. This is why so many comets change their spin as they go around the Sun, some spinning up to such high speeds that they fall apart completely.

In addition, the spin of a smaller comet changes more readily than the spin of a larger one. At roughly a kilometer wide – about the length of 10 football fields laid end to end – 41P is small enough for those gas jets to have an outsized effect.

If the Sun heated it unevenly, or if the distribution of its ice content was lopsided, its rapid reversal is relatively easy to explain mathematically.

Now, there's still a little bit of a question mark. The light-curve measurements taken of 41P can give its spin rate, but not its spin direction.

Jewitt arrived at his conclusions by plotting the lightcurves along with new estimates of the comet's size, calculated from archival Hubble Space Telescope data. He could only make them line up smoothly if the comet's spin had slowed to zero and then flipped.

"The observed, rapid changes are natural consequences of torques from outgassed volatiles acting on the very small nucleus," Jewitt writes in his preprint, which has not yet been peer-reviewed.

If 41P's spin continues evolving at the rate seen in 2017, it could spin itself apart within a few short decades, Jewitt found. We don't know yet if that's the case. There are no published spin rates from its September 2022 perihelion. The next opportunity to measure its spin rate will be its 2028 perihelion.

Comets are among the more fascinating relics of the early Solar System. They're fragile and change rapidly, but somehow they're still here, 4.5 billion years after the Solar System formed.

The changes displayed by 41P over the course of 2017, and the decades prior, suggest that it may be the remnant of a much larger comet that has been gradually whittled away by its long, slow dance with the Sun.

The Life of Earth

https://chuckincardinal.blogspot.com/

The Sleep Mistake Putting Millions of Runners at Risk

BY U. OF SOUTH AUSTRALIA, FEB. 19, 2026

https://scitechdaily.com/the-sleep-mistake-putting-millions-of-runners-at-risk/

Poor sleep significantly raises the risk of running injuries. Getting consistent, high-quality rest may be one of the most effective tools for staying healthy and performing at your best.

 Credit: Shutterstock

A new study suggests that skimping on sleep could nearly double your chances of getting injured while running.

More than 620 million people worldwide run regularly, and many of them head out early in the morning. But starting your run without enough rest the night before could significantly raise your chances of getting injured.

That is the conclusion of new research led by Professor Jan de Jonge, a work and sports psychologist at Eindhoven University of Technology in the Netherlands (and Adjunct Professor at the University of South Australia).

In a survey involving 425 recreational runners, Prof de Jonge and his colleagues found that participants who reported shorter sleep, poorer sleep quality, or frequent sleep disturbances were nearly twice as likely to suffer an injury.

The study, published in Applied Sciences, offers what Prof de Jonge describes as “compelling evidence that sleep is a critical yet often overlooked component of injury prevention.”

“While runners specifically focus on mileage, nutrition, and recovery strategies, sleep tends to fall to the bottom of the list,” he says.

“Our research shows that poor sleepers were 1.78 times more likely to report injuries than those with stable, good quality sleep, with a 68% likelihood of sustaining an injury over a 12-month period. That’s a strong reminder that how well you rest is just as important as how hard you train.”

Recreational running is one of the world’s most popular sports, but it also carries a high injury risk, particularly for those who are poor sleepers. 

Credit: University of South Australia



Why Sleep Matters for Injury Prevention

Recreational running is among the most popular sports globally, yet injuries are extremely common. Up to 90% of runners experience an injury at some point, leading to substantial medical costs and lost work time each year.

This study stands out because it looked at sleep from multiple angles. Instead of focusing only on how long people slept, the researchers also examined sleep quality and the presence of sleep disorders to better understand their combined effect on injury risk.

“Sleep is a vital biological process that allows the body and mind to recover and adapt to the physical and mental demands of training,” Prof de Jonge explains. “When sleep is disrupted or insufficient, the body’s ability to repair tissues, regulate hormones, and maintain focus diminishes, all of which can increase injury risk.”

The findings showed that runners who regularly struggled to fall asleep, woke up frequently during the night, or did not feel refreshed in the morning faced the greatest risk. In contrast, runners who maintained steady sleep schedules and good sleep quality reported fewer injuries overall.

Rethinking Training and Recovery Priorities

According to Prof de Jonge, these results carry important implications for recreational and competitive runners alike, as well as for coaches and health professionals.

“We often assume that more training equals better performance, but that’s not necessarily the case.”

“Runners – especially those balancing training with work, family, and social commitments – may actually need more sleep than average adults to recover properly. Sleep should be treated as a performance priority, not an afterthought.”

Experts generally recommend seven to nine hours of sleep per night. Athletes may require additional rest, including daytime naps, to fully support physical and mental recovery.

Practical steps such as maintaining a regular bedtime, limiting screen exposure before sleep, reducing caffeine and alcohol intake, and keeping the bedroom quiet and cool can all help improve sleep quality.

“Sleep quality and sleep duration are both important, but quantity often provides the bedrock. Sleep should be recognized not only as a recovery tool, but also as a potential predictor of injury vulnerability in recreational sports.”

The Life of Earth

https://chuckincardinal.blogspot.com/

Giant Gravity Anomaly Under Antarctica Is Getting Stronger, Scientists Reveal

19 Feb. 2026, By M. STARR

https://www.sciencealert.com/giant-gravity-anomaly-under-antarctica-is-getting-stronger-scientists-reveal

The Antarctic Geoid Low. 

(GReD)

Although Earth is approximately spherical, its gravity field doesn't adhere to the same geometry. In visualizations, it more closely resembles a potato, with bumps and divots.

One of the strongest of these depressions – where the gravity field is weaker – lies under Antarctica. Now, new models of how the so-called Antarctic Geoid Low evolved over time have shown that it's only getting stronger, driven by the long, slow movement of rock deep below Earth's surface, like a giant shifting in its sleep.

"If we can better understand how Earth's interior shapes gravity and sea levels, we gain insight into factors that may matter for the growth and stability of large ice sheets," says geophysicist Alessandro Forte of the University of Florida.

Earth's geoid – the bumpy potato shape of the gravitational field – is uneven because gravity is linked to mass, and the mass distribution inside the planet is uneven, due to different rock compositions having different densities.

https://www.youtube.com/watch?v=iCptIGM1cg8&t=1s

It's not a huge difference that you'd notice at the surface. Maps tend to exaggerate it so we can see what's going on; if you weighed yourself at a geoid low and a geoid high, the difference would be just a few grams.

Nevertheless, the geoid represents a window into processes deep inside Earth that we can't observe directly.

Forte and his colleague, geophysicist Petar Glišović of the Paris Institute of Earth Physics in France, generated a detailed map of the Antarctic Geoid Low using another window into Earth's interior: earthquakes. Seismic waves from earthquakes travel through the planet, changing speed and direction as they encounter materials with different compositions and densities.

"Imagine doing a CT scan of the whole Earth, but we don't have X-rays like we do in a medical office," Forte explains. "We have earthquakes. Earthquake waves provide the 'light' that illuminates the interior of the planet."

Using the earthquake data, the researchers constructed a 3D density model of Earth's mantle and extrapolated it into a new map of the entire planetary geoid. They compared this map with the gold-standard gravity data collected by satellites and found it to be a close match.

That was the easy part. The next step was to try to turn back the clock to assess how the geoid has evolved since the early Cenozoic, 70 million years ago.

Forte and Glišović fed their map into a physics-based model of Earth's mantle convection, rewinding Earth's interior geological activity to see how the geoid evolved over that timeframe.

Then, from their starting point, they let the model run forward to see if it could reproduce the geoid we see today.

They also checked whether their model reproduced real changes in Earth's rotational axis known as True Polar Wander. It arrived at the current geoid and matched the polar wander, suggesting it also provides an accurate representation of the geoid's evolution.

The results showed that the Antarctic Geoid Low is not a new development; a gravitational depression has been sitting near Antarctica for at least 70 million years. But it hasn't remained static. About 50 million years ago, its position and strength started to change dramatically – timing that matches a sharp bend in the polar wander.

According to the model, the anomaly formed as tectonic slabs subducted beneath Antarctica and sank deep into the mantle, altering the planet's gravity field at the surface. Meanwhile, a broad region of hot, buoyant material rose upward, becoming more influential over the past 40 million years and strengthening the geoid low.

Interestingly, this may be linked to the glaciation of Antarctica, which began in earnest around 34 million years ago. It's only a speculative link, but here's the interesting thing about the geoid: it shapes sea level. So, as the geoid shifted downward around Antarctica, the local sea surface would have lowered with it – potentially influencing the growth of the ice sheet.

That's obviously a hypothesis that requires further testing. However, the work does show that different geodynamic processes, from mantle convection to the geoid to the motion of the poles, can all be connected and influence each other.

The gravity hole under Antarctica may be subtle, but it is a reminder that even the slowest processes deep inside Earth can leave a lasting impression on the world above.

The Life of Earth

https://chuckincardinal.blogspot.com/

Thousands of Alien Species Could Invade the Arctic, Scientists Warn

BY S. BRANDSLET, NORWEGIAN U. OF SCI. AND TECH., FEB. 18, 2026

https://scitechdaily.com/thousands-of-alien-species-could-invade-the-arctic-scientists-warn/

Alien species are considered one of the greatest threats to global biodiversity, and new research suggests the Arctic may be far more vulnerable than previously thought.

 Credit: Shutterstock

More than 2,500 alien plant species could find suitable conditions in the Arctic, especially in northern Norway and Svalbard. Researchers used massive biodiversity datasets to map risk areas and improve early detection efforts.

When species are introduced outside their natural range, they can outcompete and displace native plants. The Intergovernmental Panel on Nature (IPBES) ranks invasive species among the most serious threats to global biodiversity.

To better understand the danger facing Arctic ecosystems, scientists compiled a comprehensive list of alien plant species that could establish themselves in the region. Their findings raise concern, especially at a time when expanding travel and human presence make it easier than ever for species to move across continents.

“We found a total of 2554 species that would find a suitable climatic niche in today’s Arctic,” says Kristine Bakke Westergaard, an associate professor at the Department of Natural History at the NTNU University Museum (at the Norwegian University of Science and Technology).

In recent years, a surprisingly large number of alien species have managed to flourish in Svalbard. In 2024, common meadow rue, Thalictrum flavum ,was identified for the first time in Svalbard, in full bloom on a nutrient-rich slope in Barentsburg. 

Credit: Kristine Bakke Westergaard, NTNU University Museum



In practical terms, this means these species could survive if they reach the Arctic. One of the most likely ways they could arrive is by traveling unintentionally with people, for example, attached to clothing, equipment, or transported goods.

Kristine Bakke Westergaard. 

Credit: Nina Tveter NTNU

Human Activity Accelerates Arctic Species Spread

“Our results show that alien species from virtually all over the world can find a niche in the Arctic. And with all the human activity in the Arctic now, there are lots of opportunities to get there,” Westergaard said.

Westergaard and her collaborators from the Department of Natural History and the University of Liverpool carried out what is known as a “horizon scan” to anticipate future biological invasions.

“We looked at roughly 14,000 known alien plant species that can spread to places where they do not originally belong,” Westergaard said.

Massive Biodiversity Dataset Reveals Arctic Hotspots

The team drew on more than 51 million documented observations of these species. The records were sourced from the GBIF—the Global Biodiversity Information Facility—as well as other large databases and scientific publications.

The slope below the old barn and farm buildings in Longyearbyen is very nutrient-rich after manure and food scraps were dumped there for years. It’s a great place where new alien species can get established. 

Credit: Kristine Bakke Westergaard, NTNU University Museum

First author Tor Henrik Ulsted completed the research while he was a master’s student at the NTNU University Museum until 2024. He received the Faculty of Natural Science’s award for the best master’s thesis that contributes to sustainable development and has since worked to publish the findings.

Using the combined dataset, the researchers produced a map highlighting the Arctic regions most exposed to potential plant invasions.

Norway and Svalbard Among Highest-Risk Arctic Regions

“Our map shows hotspot areas in the Arctic where many alien species can tolerate the climate. The highest number of species are found in the north of Norway,” Ulsted said.

Although Norway stands out as a high-risk area, almost no part of the Arctic can be considered fully protected, including Svalbard.

This map shows hotspots for possible new alien vascular plants in the Arctic. The lighter the color, the higher the number of potential species per 1 x 1 km. 

Credit: NTNU University Museum



“Even in Svalbard, 86 alien species can find a climatic niche,” says Westergaard, who has found and studied alien species there herself.

Rapid environmental change is compounding the threat. Rising temperatures across the Arctic lately have created conditions that allow an increasing number of foreign plant species to survive and potentially spread.

Early Detection Tools to Prevent Arctic Invasions

In Norway and Svalbard, the Norwegian Biodiversity Information Centre‘s expert committees evaluate the risks posed by alien species in different regions.

“These committees have long found it to be very laborious, almost impossible, to make a list of relevant species that should be assessed as possible new alien species,” says Westergaard.

Human activity brings with it alien species and creates excellent conditions that allow them to become established in an otherwise barren Arctic landscape. The slope below the old barn and farm buildings in Barentsburg is very nutrient-rich after manure and food scraps were dumped there for years. New alien species appear here at regular intervals, even though farming ceased many years ago. 

Credit: Kristine Bakke Westergaard, NTNU University Museum



The newly developed approach provides experts with clearer species lists and a more systematic way to evaluate ecological risk in specific areas.

Supporting Global Biodiversity Goals by 2030

“Our long-term goal is to help identify alien species before they become invasive and problematic,” Ulsted said.

Detecting and managing invasive species early is far more effective than trying to control them once they are firmly established.

According to Westergaard, this strategy also advances the objectives of the Kunming-Montreal Global Biodiversity Framework, which calls for reducing the threat from alien species, including cutting their introduction and establishment by half by 2030.

The work also supports several measures outlined in the Norwegian authorities’ action plan against alien organisms.

The Life of Earth

https://chuckincardinal.blogspot.com/

Deer Create Mysterious Ultraviolet Signals That Glow in Forests

19 Feb. 2026, By J. COCKERILL

https://www.sciencealert.com/deer-create-mysterious-ultraviolet-signals-that-glow-in-forests

(NaNami Cn/500px/Getty Images)

Deer have the ability to see ultraviolet light, and a recent study shows they can also leave a glowing trail visible in those wavelengths, too.

The discovery casts a whole new light on the way deer are communicating with each other, and how they perceive their environment.

Male white-tailed deer (Odocoileus virginianus) are known for making their mark on the forest during their autumn mating season. They rub their antlers against trees and the forest floor, shedding antler velvet – the soft, blood-rich velveteen 'skin' that covers their calcified antlers as they're growing – and leaving scent marks in the form of glandular secretions, urine and poop.

These marks, known as 'deer rubs' (on trees and shrubs) and scent-marking scrapes (on the ground), act as signposts to other animals of a deer's presence: a warning to rivals, a catcall to potential mates.

But scent, it seems, is not the only language with which the deer communicate.

Scientists at the University of Georgia (UGA) in the US have discovered that these marks 'glow' in ultraviolet wavelengths, which previous studies have shown deer eyes are capable of seeing.

"The resulting photoluminescence would be visible to deer based on previously described deer visual capabilities," the team writes in their published paper describing the phenomenon.

This is the first time scientists have documented evidence of any mammal actually using photoluminescence in their environment, although UV-induced photoluminescence in mammals has been studied for more than a century.

What's more, the study checks most of the boxes needed to say whether photoluminescence is actually serving a biological function.

https://www.youtube.com/watch?v=h4ouBJ5Zrj4&t=1s

Daniel DeRose-Broeckert, a graduate research assistant at UGA, and colleagues carried out their study in a 337-hectare (about 840-acre) research forest called Whitehall, where deer roam freely.

The team tracked down deer 'signposts' – 109 rubs and 37 scrapes – during two roughly month-long surveys in the fall of 2024, and returned to each one at night with ultraviolet flashlights peaking at 365 nm and 395 nm.

Both of these wavelengths abound in the skies at twilight and dawn, when deer are most active. And since earlier research has shown deer can see reflections or emissions of these wavelengths, anything that glows bright enough under these torches would be easily visible to a deer's eye.

As a proxy, the scientists used a tool that measures irradiance values: how much light is reflected or emitted at each wavelength, from a given spot.

"Rubs and urine found on scrapes exposed to 395 and 365 nm had greater average irradiance values (i.e., brighter) than the surrounding environment, and exhibited photoluminescence," the team reports.

It's unclear how much of this glow comes from the trees and shrubs, and how much is coming from remnant deer fluids. Deer urine, for instance, contains porphyrins and amino acids that become excited under longer UV wavelengths. Phenols and terpenes released from the forehead glands of male deers are thought to have a similar quality.

When the deer damage plants, they expose woody lignin and plant terpenes, types of compounds also known to exhibit photoluminescence.

"Whether the photoluminescence is the result of deer forehead glandular secretions or wood properties, the fact remains that rubs visually contrast the surrounding environment in a way that is uniquely suited for deer vision," the team notes.

Under both kinds of UV flashlight, the photoluminescence emitted by the deer signposts was the right kind to be registered by the cones within a deer's eye that are sensitive to short- and middle-wave visible light. This, the scientists say, reaffirms that deer eyesight is adapted to the low-light conditions of dawn and dusk.

More impressively, it suggests deer are communicating with light-up 'noticeboards' throughout the forest that the rest of us can't even see.

As to what the deer are saying? Until further research is conducted, we won't know for sure.

"Though we did not directly test for a behavioral change in deer as a result of the presence of photoluminescence, the irradiance of rubs increased at the same time as deer hormone levels increased, and behavioral changes are known to change with the progression of the breeding season," the team writes.

The Life of Earth

https://chuckincardinal.blogspot.com/

Glaciers Can Suddenly And Dangerously Surge Up to 60 Meters a Day

By H. LOVELL & C. STOKES, THE CONVERSATION

https://www.sciencealert.com/glaciers-can-suddenly-and-dangerously-surge-up-to-60-meters-a-day

(DavidGreitzer/iStock/Getty Images Plus)

It's difficult to forget standing in front of a glacier that is advancing towards you, towering ice pillars constantly cracking as they inch forward. The motion is too slow to see in real time, but obvious from one day to the next.

One of us (Harold) experienced this during fieldwork in 2012 at Nathorstbreen on the Arctic archipelago of Svalbard, which was moving forwards more than 10 metres per day.

Encounters like this are rare. Most of the world's glaciers are retreating rapidly as the climate warms, and thousands are likely to disappear altogether within the next few decades.

However, a small fraction of glaciers do the opposite, and repeatedly speed up and advance for months or years after a long period of stagnation and retreat. This is known as glacier surging, and it has long puzzled scientists.

Surging glaciers in the Panmah region of the Karakoram, High Mountain Asia. 

(Frank Paul)



It might be tempting to view advancing ice as an antidote to the gloomy picture of disappearing glaciers, but the polar opposite is true. Surges can accelerate ice loss, make glaciers more vulnerable to climate change, and create serious hazards for people living downstream of them.

We have just published a global study of over 3,000 surging glaciers to find out what's causing them to move like this. Our work also summarises, for the first time, the hazards caused by these glaciers, and how surging is being affected by climate change.

Why some glaciers surge

During surges, glaciers accelerate from a slow crawl to tens of metres per day – sometimes within weeks. The fastest phase, when ice can flow at over 60 metres a day, typically lasts a year or more – although some glaciers have surged for up to 20 years. The return to low speeds and even stagnation can happen abruptly over days, or over several years.

Nathorstbreen dramatically advanced more than 15 kilometres in roughly a decade during its surge, which began in 2008 – transforming the entire landscape in a matter of years.

Field investigations at the surging front of Nathorstbreen, Svalbard in July 2012.

 (Harold Lovell)

The onset of surging is thought to be controlled by changes beneath the glacier. In surge-type glaciers, water generated by melting ice does not immediately drain away, but gathers at the bottom of the glacier. This reduces friction between ice and the ground, making it easier for ice to slide faster.

When that water eventually drains, the glacier slows again. Some glaciers experience repeated surges separated by years or decades of low ice flow – but the exact timing of surges is hard to predict.

Global hotspots of surging ice

Our study shows that at least 3,000 glaciers have surged at some point. That's only about 1% of all glaciers in the world, but they tend to be large, so represent about 16% of the global glacier area.

Notably, they are found in dense geographical groupings across the Arctic, the Himalayas and other high mountains in Asia, and the Andes – but are largely absent elsewhere. This is primarily controlled by the climate: surges do not generally happen where conditions are currently too warm, such as in the European Alps or mainland Scandinavia, or too cold and dry, such as Antarctica.

Other factors such as size and underlying geology are also important for determining which glaciers surge in a region and which do not.

Some of the hotspots are found in populated regions, where surging glaciers can become hazards. The advancing ice can overrun infrastructure and farmland, and block rivers to form dangerous lakes that can release devastating floods when the ice breaks.

An unstable lake formed by a surge of Shisper Glacier in the Karakoram mountain range drained multiple times from 2019 to 2022, causing extensive damage to the Karakoram Highway, a key connection between Pakistan and China.

https://www.youtube.com/watch?v=xTe23gDWMY4&t=1s

Fast-moving ice can cause deep cracks (crevasses) to form, affecting travel in regions such as Svalbard where glaciers provide highways between isolated human settlements. It also disrupts tourism and recreation activities, such as where climbers use glaciers to approach peaks. When glaciers surge into the sea, they release numerous icebergs in a short space of time that could present a risk to shipping and tourism.

Surging is changing as the climate warms

Climate warming is already reshaping how and when glaciers surge. In some regions, surges are becoming more frequent; in others, they are declining as glaciers thin and lose the mass needed to build towards a surge.

Heavy rainfall, intense melt periods or other extreme weather have also been shown to trigger earlier-than-expected surges, and these factors may become more important in a warming climate.

Together, this paints a picture of the increasing unpredictability of glacier surges. Some regions might experience less surging as the world warms, while others might see an increase. It is feasible that glaciers that have never surged before may begin to, including in areas where there are no records of past surges, such as the fast-warming Antarctic peninsula.

Surging glaciers remind us that ice does not always respond to warming in simple and predictable ways. Understanding these exceptions, and managing the hazards they create, is critical in a rapidly changing world.

The Life of Earth

https://chuckincardinal.blogspot.com/