Category: 7. Science

Here’s what you’ll learn when you read this story:

• Usually, when something gets warmed up, heat tends to spread outward before eventually dissipating. But things are a little different in the world of superfluid quantum gas.

• For the first time, MIT scientists have successfully imaged how heat actually travels in a wave, known as a “second sound,” through this exotic fluid.

• Understanding this dynamic could help answer questions about high-temperature superconductors and neutron stars.

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In the world of average, everyday materials, heat tends to spread out from a localized source. Drop a burning coal into a pot of water, and that liquid will slowly rise in temperature before its heat eventually dissipates. But the world is full of rare, exotic materials that don’t exactly play by these thermal rules.

Instead of spreading out as one would expect, these superfluid quantum gasses “slosh” heat side to side—it essentially propagates as a wave. Scientists call this behavior a material’s “second sound” (the first being ordinary sound via a density wave). Although this phenomenon has been observed before, it’s never been imaged. But recently, scientists at the Massachusetts Institute of Technology (MIT) were finally able to capture this movement of pure heat by developing a new method of thermography (a.k.a. heat-mapping).

The results of this study were published in the journal Science, and in an university press release highlighting the achievement, MIT assistant professor and co-author Richard Fletcher continued the boiling pot analogy to describe the inherent strangeness of “second sound” in these exotic superfluids.

“It’s as if you had a tank of water and made one half nearly boiling,” Fletcher said. “If you then watched, the water itself might look totally calm, but suddenly the other side is hot, and then the other side is hot, and the heat goes back and forth, while the water looks totally still.”

These superfluids are created when a cloud of atoms is subjected to ultra-cold temperatures approaching absolute zero (−459.67 °F). In this rare state, atoms behave differently, as they create an essentially friction-free fluid. It’s in this frictionless state that heat has been theorized to propagate like a wave.

“Second sound is the hallmark of superfluidity, but in ultracold gases so far you could only see it in this faint reflection of the density ripples that go along with it,” lead author Martin Zwierlein said in a press statement. “The character of the heat wave could not be proven before.”

To finally capture this second sound in action, Zweierlein and his team had to think outside the usual thermal box, as there’s a big problem trying to track heat of an ultracold object—it doesn’t emit the usual infrared radiation. So, MIT scientists designed a way to leverage radio frequencies to track certain subatomic particles known as “lithium-6 fermions,” which can be captured via different frequencies in relation to their temperature (i.e. warmer temperatures mean higher frequencies, and vice versa). This novel technique allowed the researchers to essentially zero in on the “hotter” frequencies (which were still very much cold) and track the resulting second wave over time.

This might feel like a big “so what?” After all, when’s the last time you had a close encounter with a superfluid quantum gas? But ask a materials scientist or astronomer, and you’ll get an entirely different answer.

While exotic superfluids may not fill up our lives (yet), understanding the properties of second wave movement could help questions regarding high-temperature superconductors (again, still at very low temperatures) or the messy physics that lie at the heart of neutron stars.

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In this study, we used an operant conditioning model in which rats had to press a lever guided by a light stimulus. The protocol allowed us to assess movement preparation (light stimulus) and execution (Go signal). The learning curve shows that animals improved their performance from the 6th training session, achieving a success rate of 55% (Fig. 2B). A significant difference in success rates between beginner and expert rats was observed from the first to the last training session, indicating that the animals progressed through the perceptual and associative learning phases. Additionally, an analysis of kinematic parameters revealed decreases in duration, reaction time, and movement amplitude, suggesting that movements became more precise and stereotyped in later training stages^33,34,35. This enabled us to assess the involvement of CS and CR pathways at different stages of the movement.

The role of the cortex in motor control is well documented. As a more evolutive recent structure compared to subcortical motor nuclei⁴the cortex modulates the spinal cord directly via the CS pathway and indirectly via projections to older motor nuclei like the red nucleus (CR pathway). These pathways are thought to be involved in different stages of movement, including planning and execution^1,2,36.

The functional diversity of neurons in layer 5 of the cortex, which are the primary output information from the cortex, is still debated. One view suggests that these neurons, which project to multiple subcortical structures^37,38play a role in associative movement control without clear compartmentalization of motor commands. This implies low functional diversity, with the same information sent to various movement-related structures simultaneously. Conversely, another perspective suggests that layer 5 neurons exhibit high functional diversity based on their specific projection targets^1,31,32,39. This last viewpoint supports the idea that the cortex regulates older motor systems and pathways, allowing for distinct control of movements by different neuronal subgroups⁴.

Our histological findings are consistent with the latter proposal, as they show a topographic segregation of the two evaluated populations (CR and CS). CR neurons are more densely located in motor regions like M1 and M2, while CS neurons are more concentrated in S1 and M1, with less presence in S2 and no presence in M2 (Fig. 1D). This distribution aligns with findings from other studies, which show that there is a differential distribution of layer 5 projection neurons depending on their target site^25,31,40,41. Studies, such as those by Kita and Kita³⁸have shown that the subthalamic nucleus of rats mainly receives long-range axon collaterals with multiple subcortical targets. Similarly, Guo found that layer 5 type I neurons in mice have a high probability of projecting to multiple regions, with the thalamus and midbrain being the most frequent targets^37,38. Unlike previous research that reported cortical projection neurons sending collaterals to multiple subcortical structures, this study found a low percentage (about 10%) of double-labeled neurons. Our data are similar to those reported by Akintunde⁴⁰who found approximately 4% of neurons doubly labeled with CR and CS. The discrepancies between the studies may be related to the methodologies used for the measurements, which in some cases involved viral infections and in others retrograde markers^37,38,40. Here we show a relatively smaller number of double-labeled corticorrobral and corticospinal cells in M2 than in M1 and S1FL (Fig. 1C). The differences in the proportion of double-labeled neurons in M2 compared with M1 and S1 could be due to the topographic distribution of CS neurons. The proportion of CS neurons labeled in S1 y larger than CR neurons. This difference is inverted in M2, in which CR neurons are more abundant and very few CS neurons were found. However, in M1, the proportion of CS and CR is similar (Fig. 1C). Moreover, our group Olivares et al.²⁵ and others Kameda et al.⁴² have described that CS axons from motor-related (M1 and M2) and somatosensory areas (S1 and S2) project differentially to a transverse plane of spinal gray matter. Whereas axons from M1 and M2 are distributed similarly into the ventromedial region of the contralateral gray matter. This suggests that L5 pyramidal tract neurons from different cortical areas play distinct functional roles.

For this study, we injected a retrograde virus into the spinal cord and red nucleus to analyze the role of these pathways during movement (Fig. 3A). In addition, we applied optogenetic inhibition protocols to investigate their effects on movement phases (Fig. 3E). Fibers were implanted in the M1 where these neuron populations converge (Fig. 3D). Each animal has a particular way to perform the movement (see the new Supplementary Fig. 6). So, we observed distinct trajectory profiles in different rats, no matter which injections were performed. Moreover, we did not observe any statistical difference in the duration of the control trajectories of CR compared with CS rats (compare, for example, the trajectories of Figs. 4 and 5). Additionally, different trajectory profiles were also observed in intact animals without any injection, for that reason, the trajectory comparison was computed independently for each animal.

No significant change in the success rate was observed in any of the types of inhibition in the CR group of animals compared to their control (Fig. 5B). This suggests that the animals performed the task successfully despite the inhibition. Other studies have reported more pronounced effects with lesions or total inhibitions^43,44. However, differences associated with movement preparation were found in the CS group during early inhibition. This finding is consistent with the function of CS neurons projecting to the dorsal horn, which may be involved in modulating sensory and proprioceptive inputs^25,41 (Fig. 4B). Here, the ability to inhibit CS and CR neurons is restricted by the numerical aperture of the fiber used, which limits the effect to a radius of 200 micrometers. Therefore, it is not possible to observe an effect as drastic as that reported in studies where complete lesions or inhibitions of the pathways were performed^43,44. Additionally, although the lever movement was still performed, changes in execution were observed, prompting an analysis of various kinematic parameters to identify these alterations.

Early inhibition of CS neurons increased significantly the duration of lever pressing (Fig. 4C), pull acceleration (Supplementary Fig. 4D) and, a tendency to increase in pull speed (Supplementary Fig. 4B) compared to their controls. The changes observed when inhibiting a preparatory phase and an execution phase can be explained by the fact that the CS tract has distinct neuronal subgroups that modulate sensory information and motor execution^23,25and different subtypes of spinal cord interneurons²³. Thus, the CS tract could play a key role in sensorimotor integration by modulating the synaptic noise into the spinal cord and receiving motor commands^24,25,45,46.

These changes in CS inhibition are consistent with the observed alterations in animal trajectories (Fig. 6A), suggesting that the longer lever press duration and increased release pull acceleration may indicate a decrease in control over the lever return movement (flexion movement). In this way, Fetz et al. have shown that the CS tract facilitates both flexor muscles (51%) and extensor muscles (48%)^6,47. However, the minimal effect on lever execution observed with CS neuron inhibition aligns with findings that CS neuron involvement in movements changes with training⁴¹. In expert animals, CS neurons in area M1 are active before and during movement execution, but their role may decrease in highly trained movements⁴⁸. This indicates that the cortex becomes less involved in executing well-learned movements and only re-engages to make corrections in response to external disturbances when needed^49,50,51.

Early and late inhibition of CR neurons significantly affected lever execution. Late inhibition decreases the duration of lever pressing (Fig. 5C) while significantly decreasing amplitude (Fig. 5B), pull and push speeds, and pull accelerations in both inhibitions. These effects are in line with changes observed in trajectory performance (Fig. 6B), indicating issues with initiating and executing the movement, including extension (lever press) and flexion (lever release) phases. Some studies have linked damage to the CR tract and disinhibition of the red nucleus with forelimb extension problems⁵². However, these studies have not been replicated. On the other hand, it has been demonstrated that the rubrospinal tract controls both extensor and flexor muscles^6,47which is consistent with the results observed in our study.

Early phase inhibition may be linked to CR tract modulation of red nucleus activity, which indirectly affects the rubrospinal tract. This modulation probably regulates the excitability of signals from the contralateral interposed nucleus of the cerebellum^18,53. Thus, the CR tract not only aids in the initiation and termination of voluntary movements but also modulates the red nucleus’s basal activity^18,53which is crucial for proper movement execution. Additionally, early-phase CR neuron inhibition increased reaction times (Fig. 5D), which is consistent with findings in cats where red nucleus neurons are active during reaction times before lever release⁵⁴ .

Inhibition of CR neurons during the late phase caused a significant decrease in parameters such as movement duration (Fig. 5C), pull and push speed (Supplementary Fig. 4A,B), pull acceleration (Supplementary Fig. 4D), and increase in push time (Supplementary Fig. 4E). Similar results have been observed when inhibiting M2 and M1 cortices in mice, disrupting the proper execution of a reaching movement⁵⁵. On the other hand, training has been found to strengthen the association between M2 and M1 areas, as well as their relationship to motor performance⁵⁶. Considering the high population density of CR neurons in these two areas (Fig. 1D), it could be argued that this neuronal population is involved in both the preparation and execution of movements.

The convergence of CS and rubrospinal projections on their targets within the spinal cord, modulating local interneurons and propriospinal neurons^28,29,30has led to the suggestion that there is a close relationship between these two motor pathways. Additionally, it has been documented that when there is damage to the red nucleus or loss of the cortico-rubrospinal pathway, movement execution is impaired, although there may be some compensation from the CS tract. Similarly, plasticity has been observed in the cortico-rubrospinal tract when there is damage to the CS tract^26,43,44,57. In both cases, recovery is incomplete, suggesting that they are complementary pathways for transmitting information rather than copies of the same motor command.

Considering that the cortex and the parvocellular region of the red nucleus (CR target) emerged almost simultaneously during evolution, perhaps in response to the need for better limb control and increased complexity of movements beyond locomotion and “gross” movements, it raises the question of how these new structures and the preexisting ones are reorganized for motor control⁴. Kennedy proposes that the CS system, is predominantly involved in the learning of new movements, nonetheless, the cortico-rubro-olivary tract and the rubrospinal tract more with the proper execution of learned or automated movements⁵⁸. Yet, the animals we evaluated are experts, which explains the differences in the involvement of the two pathways, with more evident changes during CR neuron inhibition^58,59,60.

It has been shown that CS neurons participate in movement preparation⁴⁶ and the perturbation of movement preparation affects the motor execution⁵⁵. The fact that the early inhibition of CS neurons reduces the number of hits (Fig. 4B) indicates that when CS neurons are inhibited during movement preparation, the execution is affected, and the animals cannot complete the lever pressing. On the other hand, the inhibition of CR neurons, which are involved in movement triggering⁶¹affects the movement performance and reaction time (Fig. 5E). Finally, our study demonstrated that CR and CS neurons, subpopulations of PTNs, play an essential role in motor performance by modulating various kinematic parameters. These findings suggest that these neuronal populations contribute differently to sensorimotor integration, indicating that the cerebral cortex can reorganize neural circuits to execute a previously learned movement, even under inhibition conditions⁵⁰. In this regard, it is suggested that these two pathways are necessary for proper preparation and execution of a movement.

Limitations of the study

This study highlights limitations that should be considered when interpreting the findings. First, the use of retrograde labeling from 2 different structures may underestimate the true number of single and double projection neurons, potentially biasing the anatomical characterization of the circuits. Additionally, the lack of direct quantification of optogenetic inhibition in labeled and unlabeled neurons does not allow for a full understanding of the effects of both suppression and rebound excitation of the neuronal circuit, which may have on the behavioral outcomes. Third, the absence of stereotyped movements across mice further complicates the interpretation of behavioral data, as it precludes a clear assessment of the effects of viral manipulations alone, independent of light stimulation. Finally, the spatial resolution of optogenetic suppression, constrained to an approximate 200 μm radius, along with variable labeling efficiency, may have led to an underestimation of the functional contributions of the CS and CR pathways. Future experiments using electrophysiological recordings of CS and CR during movement performance could directly reveal if both types of pyramidal tract neurons has specific roles in motor preparation and execution.

Scientists in China have created rainbow, glow-in-the-dark succulents by injecting colorful “afterglow” particles into the leaves that absorb and then gradually release, light.

Plants were first engineered to glow in 1986, when researchers at the University of California San Diego transferred a firefly gene into tobacco plants.

More types of plants now glow, such as the firefly petunia that went on the market last year, thanks to the insertion of fungal genes that bestow luminescence. However, engineered plants’ glows range in color only from yellowish green to greenish blue.

Taking a different tack, a team at the South China Agricultural University injected six plant species, including the popular succulent Echeveria, with micron-size bits of phosphor, called “afterglow particles,” that temporarily luminesce green after exposure to white light.

The particles glowed the brightest and most evenly in Echeveria because the injected fluid diffused throughout each leaf, the team published their findings in The Journal of Matter on August 27, 2025.

Further injections of Echeveria with other kinds of afterglow particles created light of additional colors, depending mainly on the chemical composition of the particles.

Could it be an alternate to your night lamp?

These plants are no Burning bushes: The illumination is equivalent to a small nightlight and drops off after 10 minutes.

That said, throughout the 10-day experiment, the phosphor-laden leaves could be regularly recharged by white light, just like glow – in the dark stickers.

One difficulty for growers, compared with planting transgenic seeds, is that each leaf must be injected individually.

Succulents like Echeveria are difficult to genetically modify, so the approach could expand the range of decorative glowing plants.

Voyager 1 recently made a groundbreaking discovery just beyond the edge of our solar system, detecting a wall of a fire-zone of incredibly hot, energetic particles that was completely unexpected.

Voyager 1 has been exploring the vastness of space for nearly five decades and this significant finding is reshaping how scientists understand Earth’s cosmic neighborhood.

It was an unexpected discovery. Voyager 1 has detected a wall of fire where temperatures soar to nearly 54,000 degrees Fahrenheit. It seems like something out of science fiction, but these scorching temperatures are very real and hidden away in the depths of Space.

Voyager’s instruments have detected a surprising rise in both temperatures and density of particles as it crossed the boundary of the solar system.

Scientists have aptly named this region the “wall of fire” because it is a massive zone of energetic particles that creates an intense heatwave at the solar system’s edge.

The recent findings from Voyager 1 are that magnetic fields inside the heliopause, and subsequently in interstellar space are surprisingly similar.

Scientists expected dramatically distinct magnetic environments between our solar bubble and the vast galaxy after the heliopause.

What is the heliopause?

It is the outermost boundary where the sun’s magnetic influence and solar wind pressure meet the cold and desolation of interstellar space.

For many years, researchers theorized that this edge could be cold and scattered, but Voyager’s first findings have turned that notion.

Voyager 1, an interstellar pioneer

Voyager 1 will continue its journey beyond the “wall of fire” and keep measuring the density of charged particles and the intricate behavior of magnetic fields as it travels deeper into interstellar space.

Voyage 1 sends back is a new piece in the puzzle of our place in the galaxy, marking a key moment in humanity’s quest of knowledge beyond the familiar planets.

This week in science: The US puts together new guidelines for blood pressure; sections of the seafloor found to be strangely upside down; the brightest radio flash ever detected; and much more!

The Mütter medical museum in the US will no longer accept donations of unidentified human remains, due to ethical concerns:

“After two years of controversy over how to ethically exhibit human remains, the Mütter Museum announced last week it has changed its policy to ‘contextualize’ and de-anonymize its collection.”

Read the full story here.

Wearing a rose scent oil for a month increased brain volume of participants in a new study, compared to those not wearing a scent.

“This study is the first to show that continuous scent inhalation changes brain structure,” write the researchers in their published paper.

Read the full story here.

Medical institutions in the US have updated the guidelines for high blood pressure, with a focus on prevention and earlier intervention.

The updated guidelines replace a previous revision conducted in 2017, and are a joint effort from the American Heart Association (AHA), the American College of Cardiology (ACC), and other respected institutions in the US.

Read the full story here.

Giant chunks of the seafloor have been found ‘upside down’ in the North Sea, with younger, denser layers sinking below older, lighter ones.

These vast sand mounds pile atop structures known as sinkites, the result of a process called stratigraphic inversion, and never before have they been found in such large numbers.

Read the full story here.

The CHIME radio telescope has detected the brightest radio flash of all time, coming from a galaxy 130 million light-years away.

It has been named the RBFLOAT, or radio-brightest flash of all time (also known as the Root Beer FLOAT, because astronomers like to amuse themselves that way).

Read the full story here.

The microbes in your gut have been linked to insomnia, with some types increasing the risk and others reducing it.

What’s more, the relationship appears to go both ways: poor sleep can disrupt the gut’s microbial balance, creating a feedback loop that could make insomnia harder to shake.

Read the full story here.

How did the building blocks of life come together to spawn the first organisms? It’s one of the most longstanding questions in biology — and scientists just got a major clue.

In a new study published in the journal Nature, a team of biologists say they’ve demonstrated how RNA molecules and amino acids could combine, by purely random interactions, to form proteins — the tireless molecules that are essential for carrying out nearly all of a cell’s functions. 

Proteins don’t replicate themselves but are created inside a cell’s complex molecular machine called a ribosome, based on instructions carried by RNA. That leads to a chicken-and-egg problem: cells wouldn’t exist without proteins, but proteins are created inside cells. Now we’ve gotten a glimpse at how proteins could form before these biological factories existed, snapping a major puzzle piece into place.

“We have achieved the first part of that complex process, using very simple chemistry in water at neutral pH to link amino acids to RNA,” said study coauthor Matthew Powner, a chemist at University College London, in a statement about the work. “The chemistry is spontaneous, selective, and could have occurred on early Earth.”

The results, he added, show how “RNA might have first come to control protein synthesis.”

Amino acids have been around far longer than life has on our planet. We’ve even found amino acids — plus all the five major ingredients of DNA and RNA called nucleotides — on asteroid samples plucked directly from outer space.

The curious thing about amino acids, though, is that they don’t easily link together; something has to kickstart the chemistry that allows life as we know it.

To find out what that might be, the researchers focused on a reactive molecule called pantetheine, which is already known for its crucial role in metabolism. In a previous study, the researchers found that these compounds were likely abundant in lakes on early Earth. 

When they threw together a watery stew of pantetheine and amino acids, the team found that the amino acids reacted with the compound to create another chemical called aminoacyl-thiol. This thiol, they further demonstrated, combined with free-floating RNA in water at a neutral pH to start a reaction that transferred the amino acids to the RNA, linking them together.

“In a scenario where you have amino acids, where you have RNA molecules, if you have thiols — sulfur molecules — this is, I think, almost inevitable that this kind of process can happen,” Powner told the Washington Post.

The catch is that as far as we can tell, the pantetheine crucial to making this all happen wouldn’t have been found in high enough concentrations in the Earth’s primordial oceans, where many scientists believe life may have originated— only in smaller bodies of freshwater, where it would be less diluted. Nick Lane, an origin of life chemist at UCL who wasn’t involved in the study, further cautioned to Science that the amino acid chains being produced are random and chaotic, unlike the orderly arrangements produced by ribosomes.

“They still have not cracked that problem,” he told the magazine.

But give these chemicals billions of years to bounce around, and anything can happen.

More on life’s origins: Scientists Find Evidence That Original Life on Earth Was Assembled From Material in Space

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On August 27, 2025, deep imaging of the interstellar object 3I/ATLAS by the Gemini South 8.2-meter telescope — aided by the Gemini Multi-Object Spectrograph (GMOS), revealed a weak tail with a teardrop shape in the anti-Sun direction (reported here). At that time, 3I/ATLAS was at a distance from Earth of 2.59 times the Earth-Sun separation. The Gemini South Observatory is located on a mountain called Cerro Pachón in the Chilean Andes.

The images were taken in the u (upper left), g (upper right), r (lower left) and i (lower right) spectral bands, centered on wavelengths of 0.365, 0.467, 0.616 and 0.747 micrometers, respectively. They show clear evidence for a teardrop shaped tail in the anti-Sun direction behind 3I/ATLAS. The observed tail is about 30 arcseconds, or equivalently 56,000 kilometers long, pointing towards the South East. The coma is about 10 arcseconds or equivalently 18,800 kilometers wide, significantly more extended than its compact appearance in images of 3I/ATLAS from early July 2025.

Data collected on August 6, 2025 by the Webb Telescope (accessible here) confirmed the existence of a carbon dioxide (CO2) gas plume around 3I/ATLAS with an order of magnitude lower levels of water (H2O) and carbon monoxide (CO), as reported earlier by the SPHEREx space observatory team (here). SPHEREx mapped the CO2 plume out to 348,000 kilometers around 3I/ATLAS. The inferred mass loss rates from 3I/ATLAS are 130 kilograms per second for CO2, 6.6 kilograms per second for H2O and 14 kilograms per second of CO. The H2O mass loss rate is only 5% of the CO2 output, unlike expectations from a water-rich comet.

It therefore comes as no surprise that the plume of gas around 3I/ATLAS is shaped by the solar wind and the solar radiation pressure to a teardrop configuration. Before my morning jog at sunrise, I calculated today that the outer edge of the CO2 plume observed by SPHEREx, is bounded by the distance where the ram-pressure of the solar wind equals the ram-pressure of the CO2 outflow.

As of now, it is unclear whether the scattering of sunlight in the glow and tail around 3I/ATLAS is from dust particles or icy fragments made of CO2, CO and H2O that broke off the surface of the nucleus.

Early data from NASA’s Transiting Exoplanet Survey Satellite (TESS), taken on May 7 to June 2, 2025 (accessible here), suggests that 3I/ATLAS may have been active with a surrounding glow of scattered sunlight already at a much larger heliocentric distance of 6 times the Earth-Sun separation. At that distance, the warming of water ice by sunlight is insufficient to trigger cometary activity.

The flux detected by the SPHEREx space observatory at a wavelength of 1 micrometer from 3I/ATLAS on August 8–12, 2025 suggests a huge nucleus or alternatively a compact scattering cloud, with a diameter of 46 kilometers (as reported here). If made of solid material, this size implies that the mass of 3I/ATLAS is a million times larger than that of the previous interstellar comet 2I/Borisov. This huge gap in mass is surprising since we should have discovered numerous objects of the size of 2I/Borisov before discovering a 46-kilometer interstellar object. Moreover, as I noted when 3I/ATLAS was discovered (in a paper accessible here), the amount of rocky material per unit volume in interstellar space is much too small than the value needed to deliver into the inner Solar system one giant rock of this size over the decade-long survey conducted by the ATLAS telescope. In another puzzling tidbit, the trajectory of 3I/ATLAS is anomalously aligned with the ecliptic plane of the planets around the Sun (as discussed here).

Recent spectroscopic data from the Very Large Telescope in Chile (accessible here), reported the surprising detection of cyanide and nickel without iron in the plume of gas around 3I/ATLAS with steeply increasing rates as the object approaches the Sun. Nickel without iron is a signature of industrial production of nickel alloys. Natural comets generically show iron and nickel simultaneously, as both elements are produced simultaneously in supernova explosions.

All this anomalous data raises once again the fundamental questions: what is the nature and origin of 3I/ATLAS?

As 3I/ATLAS will approach perihelion on October 29, 2025, its surface will get warmer and its enhanced outgassing will encounter stronger radiation and wind pressures from the Sun. As is well known from interrogation tactics, a high stress environment elicits confessions. For that reason, 3I/ATLAS might reveal its nature and origin in the coming months.

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This story originally appeared on Grist and is part of the Climate Desk collaboration.

Seen from space, Antarctica looks so much simpler than the other continents—a great sheet of ice set in contrast to the dark waters of the encircling Southern Ocean. Get closer, though, and you’ll find not a simple cap of frozen water, but an extraordinarily complex interplay between the ocean, sea ice, and ice sheets and shelves.

That relationship is in serious peril. A new paper in the journal Nature catalogs how several “abrupt changes,” like the precipitous loss of sea ice over the last decade, are unfolding in Antarctica and its surrounding waters, reinforcing one another and threatening to send the continent past the point of no return—and flood coastal cities everywhere as the sea rises several feet.

“We’re seeing a whole range of abrupt and surprising changes developing across Antarctica, but these aren’t happening in isolation,” said climate scientist Nerilie Abram, lead author of the paper. (She conducted the research while at Australian National University but is now chief scientist at the Australian Antarctic Division.) “When we change one part of the system, that has knock-on effects that worsen the changes in other parts of the system. And we’re talking about changes that also have global consequences.”

Scientists define abrupt change as a bit of the environment changing much faster than expected. In Antarctica these can occur on a range of times scales, from days or weeks for an ice shelf collapse, and centuries and beyond for the ice sheets. Unfortunately, these abrupt changes can self-perpetuate and become unstoppable as humans continue to warm the planet. “It’s the choices that we’re making right now, and this decade and the next, for greenhouse gas emissions that will set in place those commitments to long-term change,” Abram said.

A major driver of Antarctica’s cascading crises is the loss of floating sea ice, which forms during winter. In 2014, it hit a peak extent (at least since satellite observations began in 1978) around Antarctica of 20.11 million square kilometers, or 7.76 million square miles. But since then, the coverage of sea ice has fallen not just precipitously, but almost unbelievably, contracting by 75 miles closer to the coast. During winters, when sea ice reaches its maximum coverage, it has declined 4.4 times faster around Antarctica than it has in the Arctic in the last decade.

Put another way: The loss of winter sea ice in Antarctica over just the past decade is similar to what the Arctic has lost over the last 46 years. “People always thought the Antarctic was not changing compared to the Arctic, and I think now we’re seeing signs that that’s no longer the case,” said climatologist Ryan Fogt, who studies Antarctica at Ohio University but wasn’t involved in the new paper. “We’re seeing just as rapid—and in many cases, more rapid—change in the Antarctic than the Arctic lately.”

While scientists need to collect more data to determine if this is the beginning of a fundamental shift in Antarctica, the signals so far are ominous. “We’re starting to see the pieces of the picture begin to emerge that we very well might be in this new state of dramatic loss of Antarctic sea ice,” said Zachary M. Labe, a climate scientist who studies the region at the research group Climate Central, which wasn’t involved in the new paper.

Now, a new study in mice led by researchers at Washington University School of Medicine in St. Louis and the Baylor College of Medicine reveals a previously unknown cellular purging process that may help injured cells revert to a stem cell-like state more rapidly. The investigators dubbed this newly discovered response cathartocytosis, taking from Greek root words that mean cellular cleansing.

Published online in the journal Cell Reports, the study used a mouse model of stomach injury to provide new insights into how cells heal, or fail to heal, in response to damage, such as from an infection or inflammatory disease.

“After an injury, the cell’s job is to repair that injury. But the cell’s mature cellular machinery for doing its normal job gets in the way,” said first author Jeffrey W. Brown, MD, PhD, an assistant professor of medicine in the Division of Gastroenterology at WashU Medicine. “So, this cellular cleanse is a quick way of getting rid of that machinery so it can rapidly become a small, primitive cell capable of proliferating and repairing the injury. We identified this process in the GI tract, but we suspect it is relevant in other tissues as well.”

Brown likened the process to a “vomiting” or jettisoning of waste that essentially adds a shortcut, helping the cell declutter and focus on regrowing healthy tissues faster than it would be able to if it could only perform a gradual, controlled degradation of waste.

As with many shortcuts, this one has potential downsides: According to the investigators, cathartocytosis is fast but messy, which may help shed light on how injury responses can go wrong, especially in the setting of chronic injury. For example, ongoing cathartocytosis in response to an infection is a sign of chronic inflammation and recurring cell damage that is a breeding ground for cancer. In fact, the festering mess of ejected cellular waste that results from all that cathartocytosis may also be a way to identify or track cancer, according to the researchers.

A novel cellular process

The researchers identified cathartocytosis within an important regenerative injury response called paligenosis, which was first described in 2018 by the current study’s senior author, Jason C. Mills, MD, PhD. Now at the Baylor College of Medicine, Mills began this work while he was a faculty member in the Division of Gastroenterology at WashU Medicine and Brown was a postdoctoral researcher in his lab.

In paligenosis, injured cells shift away from their normal roles and undergo a reprogramming process to an immature state, behaving like rapidly dividing stem cells, as happens during development. Originally, the researchers assumed the decluttering of cellular machinery in preparation for this reprogramming happens entirely inside cellular compartments called lysosomes, where waste is digested in a slow and contained process.

From the start, though, the researchers noticed debris outside the cells. They initially dismissed this as unimportant, but the more external waste they saw in their early studies, the more Brown began to suspect that something deliberate was going on. He utilized a model of mouse stomach injury that triggered the reprogramming of mature cells to a stem cell state all at once, making it obvious that the “vomiting” response — now happening in all the stomach cells simultaneously — was a feature of paligenosis, not a bug. In other words, the vomiting process was not just an accidental spill here and there but a newly identified, standard way cells behaved in response to injury.

Although they discovered cathartocytosis happening during paligenosis, the researchers said cells could potentially use cathartocytosis to jettison waste in other, more worrisome situations, like giving mature cells that ability to start to act like cancer cells.

The downside to downsizing

While the newly discovered cathartocytosis process may help injured cells proceed through paligenosis and regenerate healthy tissue more rapidly, the tradeoff comes in the form of additional waste products that could fuel inflammatory states, making chronic injuries harder to resolve and correlating with increased risk of cancer development.

“In these gastric cells, paligenosis — reversion to a stem cell state for healing — is a risky process, especially now that we’ve identified the potentially inflammatory downsizing of cathartocytosis within it,” Mills said. “These cells in the stomach are long-lived, and aging cells acquire mutations. If many older mutated cells revert to stem cell states in an effort to repair an injury — and injuries also often fuel inflammation, such as during an infection — there’s an increased risk of acquiring, perpetuating and expanding harmful mutations that lead to cancer as those stem cells multiply.”

More research is needed, but the authors suspect that cathartocytosis could play a role in perpetuating injury and inflammation in Helicobacter pylori infections in the gut. H. pylori is a type of bacteria known to infect and damage the stomach, causing ulcers and increasing the risk of stomach cancer.

The findings also could point to new treatment strategies for stomach cancer and perhaps other GI cancers. Brown and WashU Medicine collaborator Koushik K. Das, MD, an associate professor of medicine, have developed an antibody that binds to parts of the cellular waste ejected during cathartocytosis, providing a way to detect when this process may be happening, especially in large quantities. In this way, cathartocytosis might be used as a marker of precancerous states that could allow for early detection and treatment.

“If we have a better understanding of this process, we could develop ways to help encourage the healing response and perhaps, in the context of chronic injury, block the damaged cells undergoing chronic cathartocytosis from contributing to cancer formation,” Brown said.

This work was supported by the National Institutes of Health (NIH), grant numbers K08DK132496, R21AI156236, P30DK052574, P30DK056338, R01DK105129, R01CA239645, F31DK136205, K99GM159354 and F31CA236506; the Department of Defense, grant number W81XWH-20-1-0630; the American Gastroenterological Association, grant numbers AGA2021-5101 and AGA2024-13-01; and a Philip and Sima Needleman Student Fellowship in Regenerative Medicine. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

On August 8, 2024, the NSF Daniel K. Inouye Solar Telescope in Hawaii achieved a historic milestone by capturing the sharpest images ever taken of a solar flare. The unprecedented observations revealed coronal loops in stunning detail. The arches of superheated plasma following the Sun’s magnetic field lines were captured at such resolution that it’s possible to see individual structures as narrow as 21 kilometres across.

To put this achievement into perspective, these plasma loops are roughly twice the width of Los Angeles, yet they arch through space in formations that span distances equivalent to several Earth diameters. The Inouye telescope’s space piercing resolution is more than 2.5 times sharper than any previous solar telescope, finally allowing astronomers to peer into the fundamental building blocks of solar flares.

The NSF Daniel K. Inouye Solar Telescope has a 4.24-meter primary mirror in an off-axis configuration to minimise scattered sunlight. It requires over 11 kilometre of coolant piping for its active cooling systems to handle the extreme heat of direct solar observation, while adaptive and active optics systems use sensors and actuators to continuously correct for atmospheric disturbances and maintain precise mirror alignment. Ten mirrors guide sunlight throughout the observatory to four instruments designed for solar imaging and magnetic field measurements.

The Hawaiian Observatory, home to the NSF Daniel K. Inouye Solar Telescope, on the summit of Haleakalā volcano (Credit : Ekrem Canli)

The discovery came almost by accident. Cole Tamburri, a PhD student at the University of Colorado Boulder and the study’s lead author, was conducting routine observations when the X1.3-class flare erupted.

“This is the first time the Inouye Solar Telescope has ever observed an X-class flare. These flares are among the most energetic events our star produces, and we were fortunate to catch this one under perfect observing conditions,” – Cole Tamburri from University of Colorado Boulder

The telescope’s Visible Broadband Imager, tuned to capture light at a specific wavelength emitted by hydrogen atoms, revealed dark threadlike loops arching through the Sun’s corona with breathtaking clarity. The team measured loop widths averaging 48.2 kilometres, with some potentially half as narrow. These measurements represent the smallest coronal loops ever imaged.

According to Tamburri, the experience resembles going from seeing a forest to suddenly seeing every single tree. The imagery reveals dark, threadlike loops arching in glowing arcades, with bright flare ribbons etched in almost impossibly sharp relief, including a compact triangular formation near the centre and a sweeping arc across the top.

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. (Credit : NSF/NSO/AURA)

For decades, theories suggested coronal loops could range from 10 to 100 kilometres in width, but confirming this observationally had been impossible until now. It finally opens the door to studying not just the sheer size of the loops but their shapes, evolution, and even the scales where magnetic reconnection, the engine behind flares, occurs.

Solar flares are among the most dangerous space weather events, capable of disrupting satellites, power grids, and communications on Earth. By understanding the structure and processes that are behind these phenomena it may just be possible to improve the models that predict when and how solar storms will impact our technology dependent world.

Perhaps most tantalising is the possibility that these newly resolved structures are elementary building blocks, the fundamental components of flare architecture. If confirmed, this discovery would mark a paradigm shift in solar physics, allowing scientists to study individual magnetic loops rather than just bundles of them.

Source : The NSF Inouye Solar Telescope Observes Its First X-Class Solar Flare and Reveals the Smallest Coronal Loops Ever Imaged