Category: 7. Science

NEWPORT NEWS, VA – Though atomic nuclei are often depicted as static clusters of protons and neutrons (nucleons), the particles are actually bustling with movement. Thus, the nucleons carry a range of momenta. Sometimes, these nucleons may even briefly interact through the strong interaction. This interaction between two nucleons can boost the momentum of both and form high-momentum nucleon pairs. This effect yields two-nucleon short-range correlations. 

Experiments at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility have studied these pairs to learn how protons and neutrons preferentially pair up at short distances. However, short-range correlations involving three or more nucleons haven’t been detected yet. Now, in Physics Letters B, researchers used data from a 2018 experiment in Jefferson Lab’s Hall A to measure the signature of three-nucleon short-range correlations for the first time. 

Physicists are pursuing these trios because they would explain the extremely high-momentum component in the nucleus. Regular nucleons, with their typical, uncorrelated momenta, make up most of the nucleon momentum distribution in the nucleus. Short-range correlated pairs produce a noticeable fraction of high-momentum nucleons but some of the higher momentum is still unaccounted for.

“We’re unraveling the nucleus to find what’s missing in our understanding,” said John Arrington, a senior scientist and Relativistic Nuclear Collisions group head at the DOE’s Lawrence Berkeley National Laboratory. “We know that the three-nucleon interaction is important in the description of nuclear properties, even though it’s a very small contribution. Until now, there’s never really been any indication that we’d observed them at all. This work provides a first glimpse at them.” 

Mirrored nuclei simplify the search 

The experiment was carried out in Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF), a DOE Office of Science user facility dedicated to nuclear physics research. To access short-range-correlated nucleons, researchers aimed CEBAF’s electron beam at nuclei. The high-energy electrons interacted with the nucleons inside these nuclei. Detecting the properties of the electrons after these interactions revealed how fast the nucleon they hit were moving. This allowed physicists to pick out events in which the electron scattered off high-momentum, short-range-correlated nucleons. 

The experiment was carried out in Jefferson Lab’s Experimental Hall A, shown here.

Protons and neutrons involved in three-nucleon short-range correlations are moving even faster than those in correlated pairs. This makes it more difficult to access in experiments. Originally, theoretical predictions proposed that accessing three-nucleon short-range correlations would require a beam energy beyond that at CEBAF. However, the researchers designed an experiment that works around this limitation by taking advantage of light nuclei. 

The team used two light nuclear targets: helium-3 and tritium. Helium-3 has two protons and one neutron; tritium has two neutrons and one proton. They are known as mirror nuclei for their similar-but-opposite composition. 

Because these light nuclei each only have three nucleons, researchers know exactly which particles are involved when an electron scatters off a three-nucleon interaction. That’s because there are no other nucleons to create other possible combinations. 

This is not the case for heavy nuclei, in which the three nucleons could be many different combinations of protons and neutrons (not to mention the short-range-correlated pairs happening in the background). The lack of other possible combinations in this experiment simplified the analysis. 

“We’re trying to show that it’s possible to study three-nucleon correlations at Jefferson Lab even though we can’t get the energies necessary to do these studies in heavy nuclei,” said Shujie Li, a research scientist at Lawrence Berkeley and a principal investigator on this experiment. “These light systems give us a clean picture — that’s the reason we put in the effort of getting a radioactive target material.”

Tritium is a radioactive isotope of hydrogen. Jefferson Lab had to implement rigorous safety precautions, including a redesign of the ventilation system in Hall A. The container that holds the radioactive tritium gas was filled at the DOE’s Savannah River National Laboratory, sealed, and shipped back to Jefferson Lab. Fortunately, the special instrumentation at Jefferson Lab allows the team to use a minimal amount of tritium, reducing potential safety concerns. 

“This is a testament to what Jefferson Lab can do,” Arrington said. “CEBAF’s high intensity beam combined with the good detectors allowed us to use less tritium.”

From atomic nuclei to neutron stars 

The results hint at the detection of three-nucleon short-range correlations. However, the researchers need more data before they feel comfortable claiming certainty. 

“We want to do a similar experiment at Jefferson Lab to get more data at higher energy so that we can confirm what we observed already is a sign of three-nucleon short-range correlations,” Li said. “Eventually we want to understand how those extreme, high-momentum nucleons are generated in the nuclear system.” 

Theory predicts these three-nucleon systems are generated in two ways. In one, three particles interact simultaneously. In the other, two nucleons interact and then one of those goes on to interact with another nucleon.

In addition to figuring out the mechanism of three-nucleon short-range correlations, the researchers would like to pin down exactly how fast they move. Ultimately, understanding short-range-correlated pairs and trios shows physicists how different particles and interactions contribute to the overall properties of the atomic nucleus, which is important for interpreting other kinds of nuclear experiments.

And this exploration brings an added bonus. Neutron stars are the remnants of exploded giant stars. Their inner workings are mysterious, but we know they are incredibly dense — just like the atomic nucleus. Physicists think that the way matter behaves inside a neutron star could be similar to the mechanisms of these short-distance nucleon interactions, meaning these experiments on matter at its tiniest scales may help interpret phenomena lightyears away. 

After all, according to Arrington, “It’s much easier to study a three-nucleon correlation in the lab than in a neutron star.”

Further Reading 
nuclei”>Particles Pick Pair Partners Differently in Small Nuclei
SRTE Support Enables Tritium Experiments at Jefferson Lab
nuclei”>Different Particles Get Different Treatment Inside Nuclei
Correlated Nucleons May Solve 35-Year-Old Mystery

Salt creeping, a phenomenon that occurs in both natural and industrial processes, describes the collection and migration of salt crystals from evaporating solutions onto surfaces. Once they start collecting, the crystals climb, spreading away from the solution. This creeping behavior, according to researchers, can cause damage or be harnessed for good, depending on the context. New research published June 30 in the journal Langmuir is the first to show salt creeping at a single-crystal scale and beneath a liquid’s meniscus.

“The work not only explains how salt creeping begins, but why it begins and when it does,” says Joseph Phelim Mooney, a postdoc in the MIT Device Research Laboratory and one of the authors of the new study. “We hope this level of insight helps others, whether they’re tackling water scarcity, preserving ancient murals, or designing longer-lasting infrastructure.”

The work is the first to directly visualize how salt crystals grow and interact with surfaces underneath a liquid meniscus, something that’s been theorized for decades but never actually imaged or confirmed at this level, and it offers fundamental insights that could impact a wide range of fields — from mineral extraction and desalination to anti-fouling coatings, membrane design for separation science, and even art conservation, where salt damage is a major threat to heritage materials.

In civil engineering applications, for example, the research can help explain why and when salt crystals start growing across surfaces like concrete, stone, or building materials. “These crystals can exert pressure and cause cracking or flaking, reducing the long-term durability of structures,” says Mooney. “By pinpointing the moment when salt begins to creep, engineers can better design protective coatings or drainage systems to prevent this form of degradation.”

For a field like art conservation, where salt can be devastating to murals, frescoes, and ancient artifacts, often forming beneath the surface before visible damage appears, the work can help identify the exact conditions that cause salt to start moving and spreading, allowing conservators to act earlier and more precisely to protect heritage objects.

The work began during Mooney’s Marie Curie Fellowship at MIT. “I was focused on improving desalination systems and quickly ran into [salt buildup as] a major roadblock,” he says. “[Salt] was everywhere, coating surfaces, clogging flow paths, and undermining the efficiency of our designs. I realized we didn’t fully understand how or why salt starts creeping across surfaces in the first place.”

That experience led Mooney to team up with colleagues to dig into the fundamentals of salt crystallization at the air–liquid–solid interface. “We wanted to zoom in, to really see the moment salt begins to move, so we turned to in situ X-ray microscopy,” he says. “What we found gave us a whole new way to think about surface fouling, material degradation, and controlled crystallization.”

The new research may, in fact, allow better control of a crystallization processes required to remove salt from water in zero-liquid discharge systems. It can also be used to explain how and when scaling happens on equipment surfaces, and may support emerging climate technologies that depend on smart control of evaporation and crystallization.

The work also supports mineral and salt extraction applications, where salt creeping can be both a bottleneck and an opportunity. In these applications, Mooney says, “by understanding the precise physics of salt formation at surfaces, operators can optimize crystal growth, improving recovery rates and reducing material losses.”

Mooney’s co-authors on the paper include fellow MIT Device Lab researchers Omer Refet Caylan, Bachir El Fil (now an associate professor at Georgia Tech), and Lenan Zhang (now an associate professor at Cornell University); Jeff Punch and Vanessa Egan of the University of Limerick; and Jintong Gao of Cornell.

The research was conducted using in situ X-ray microscopy. Mooney says the team’s big realization moment occurred when they were able to observe a single salt crystal pinning itself to the surface, which kicked off a cascading chain reaction of growth.

“People had speculated about this, but we captured it on X-ray for the first time. It felt like watching the microscopic moment where everything tips, the ignition points of a self-propagating process,” says Mooney. “Even more surprising was what followed: The salt crystal didn’t just grow passively to fill the available space. It pierced through the liquid-air interface and reshaped the meniscus itself, setting up the perfect conditions for the next crystal. That subtle, recursive mechanism had never been visually documented before — and seeing it play out in real time completely changed how we thought about salt crystallization.”

The paper, “In Situ X-ray Microscopy Unraveling the Onset of Salt Creeping at a Single-Crystal Level,” is available now in the journal Langmuir. Research was conducted in MIT.nano. 

Editors’ Highlights are summaries of recent papers by AGU’s journal editors.

Source: Geochemistry, Geophysics, Geosystems

More than a century ago, Alfred Wegener proposed that the Atlantic Ocean formed after North America drifted away from Africa and Eurasia. Much later, the theory of plate tectonics explained this movement as resulting from the formation of new oceanic crust in the space between the continents. But how did the the initial rift between the landmasses form, and how did it transition into a mid-ocean spreading ridge? Answers to these questions have remained elusive, partly because the time history of the rifting process has been difficult to decipher.

Foster-Baril et al. [2025] shed new light on the “rift to drift” transition by dating igneous rocks across a broad swath of the North American margin. They find that continental breakup and the subsequent transition to seafloor spreading was accomplished by three major pulses of magmatism. The first pulse was the largest, and involved extensive melting of mantle from below as the rift opened across a wide area. The second and third pulses, which were smaller, helped to localize the extensional deformation into a confined region. This localization facilitated the transition to symmetric seafloor spreading.

This sequence suggests that continental breakup happens across a much broader area, and over a longer time period, than was previously thought. It is still unclear if other continental breakup events also featured a series of magmatic pulses, or if the North American margin was unique in this way. Can this sequence also help us to understand “failed rifts” that never transition into seafloor spreading events? More studies that examine magmatism across broad regions of a rifting zone can help to answer such questions.

Citation: Foster-Baril, Z. S., Hinshaw, E. R., Stockli, D. F., Bailey, C. M., & Setera, J. (2025). Duration and geochemical evolution of Triassic and Jurassic magmatism along the Eastern North American Margin. Geochemistry, Geophysics, Geosystems, 26, e2024GC011900.  https://doi.org/10.1029/2024GC011900

—Clinton P. Conrad, Associate Editor, G-Cubed

Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

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Two groups of Neanderthals who camped just 43 mi apart in northern Israel left behind piles of butchered bones that look nothing alike. Yet both groups hunted the same gazelles and fallow deer, shaped the same flint flakes, and cooked beside the same kinds of hearths.

“The subtle differences in cut mark patterns between Amud and Kebara may reflect local traditions of animal carcass processing,” said Anaëlle Jallon, a PhD candidate at the Hebrew University of Jerusalem and lead author of the new study.

Neanderthals’ butchery styles

Forty percent of the animal bones at Amud cave are scorched, while only 9 percent show burning at Kebara cave, a contrast the researchers recorded in more than 11,000 catalogued fragments.

Burned bone shatters easily, and at Amud most pieces were under one square inch, yet they bristle with dense, overlapping cut marks that sometimes crisscross like city streets.

The average piece spans several square inches, and its knife scars run long and straight, rarely intersecting. Kebara fragments tell a calmer story.

Both kitchens sat within the Middle Paleolithic Mediterranean woodlands, where gazelles roamed year round and larger aurochs grazed the valley floor.

Stable isotope work shows Neanderthals there pivoted diets as climate swung, a talent shared across Eurasia.

Yet the Amud team rarely hauled full grown aurochs back to camp, focusing on smaller game that could be carried whole. Kebara hunters, in contrast, often lugged large carcasses home before filleting them inside the cave.

Measuring Neanderthal butchery

Jallon’s team zoomed a 3D surface microscope over 936 Amud incisions and 736 Kebara grooves. Most shared the same V shaped profile, confirming that both groups wielded similar flint points.

Still, the metrics diverged. Amud marks averaged 1.9 mm long but crammed onto tiny chips, producing ten cuts per square centimeter. Kebara’s averaged 3.4 mm yet only 1.6 cuts per square centimeter.

Opening angles on Amud cuts ran wider, and their floors splayed into broader arcs. Those shapes usually form when a blade bites repeatedly at different angles rather than slicing clean in one stroke.

Fire may explain part of the difference. Repeated roasting can dry collagen, making bone more brittle and forcing butchers to hack rather than glide their tools.

Amud hearths cluster near the living surface and show layers of ash glued together by rainwash, hinting at frequent burning of refuse. Kebara’s hearths sit in discrete lenses, and many bone fragments lay untouched by flame, suggesting faster cleanup or cooler cooking.

Neanderthal butchery shaped by tradition

Experimental work finds novices leave shallow, chaotic cuts, but Amud grooves run deep and regular, ruling out clumsiness. Technique, not talent, separates the two butcheries. 

“Even though Neanderthals at these two sites shared similar living conditions and faced comparable challenges, they seem to have developed distinct butchery strategies,” noted Jallon.

Instead, the team proposes social learning: each group copied elders, handing down rules about how long meat could hang, who wielded blades, and where to slice. 

One idea is meat aging. If Amud hunters dried or left carcasses to ripen, the toughened tissue would need more short, forceful strokes, exactly what the bones record.

Groups stayed apart

Despite the short distance between Amud and Kebara, there’s no direct evidence the groups ever interacted. Researchers cannot confirm whether the caves were used simultaneously or separated by centuries.

Even so, the consistent cut mark style within each cave over multiple occupation layers hints that each group may have returned seasonally, preserving their own traditions across generations.

This long-term stability suggests that Neanderthal groups maintained cultural identities even without obvious borders or physical barriers.

Cultural differences in Neanderthal butchery

The findings join a growing list of cave to cave quirks that paint Neanderthals as flexible, creative foragers rather than a single gray mass.

Previous work shows Levantine clans favored gazelles over deer even when both stood in sight, a preference that likely mixed taste, risk, and tradition.

Other studies spot regional styles in stone tool trimming, birch tar glue, and pigment use. Cut mark signatures now add food prep to the cultural toolkit, filling a daily life gap between hunting and eating.

Was Amud’s smoky workspace a seasonal smokehouse run by a few specialists, or a crowded hearth where many hands joined in?

Did Kebara cooks trim meat fast to dodge cave dwelling hyenas outside, or to feed a larger band waiting inside?

Jallon hopes that chemical traces of drying or aging, microscopic wear on knife edges, and new isotopic snapshots of collagen breakdown can test these ideas.

Nearby sites such as Ein Qashish carry similar fauna and may reveal whether butcher signatures match either cave or map onto new patterns.

The study is published in Frontiers in Environmental Archaeology.

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Even a small slowdown to one of Earth’s major ocean currents could nearly halve the rainfall over parts of the planet’s rainforests, fueling droughts that could accelerate climate change, a new study warns.

The Atlantic Meridional Overturning Circulation (AMOC), which includes the Gulf Stream, plays a key stabilizing role in climates around the planet. Yet a number of studies indicate that the current is slowing, with some even suggesting its heading toward a disastrous collapse.

For the past year, a small candy shop in Colombia has been receiving regular visits from someone who’s become their most loyal customer — this sweet dog named Laika.

“She comes here almost daily,” the owner of Dulceria Las Caleñitas Cajica told The Dodo. “We feed her.”

But bighearted Laika apparently couldn’t keep the candy shop’s kindness all to herself.

A couple of months back, Laika appeared at the door as usual — but this time she wasn’t alone.

In her company was a ginger-haired dog who was eager for a snack as well.

The candy shop created this video to show how their visits progressed:

“They’re the cutest,” the shop owner said. “I love seeing them together.”

Though both dogs have homes, they seem to prefer the warm sunlight outside of the shop. And there, they get more than just full bellies.

The candy shop’s owner has personally taken Laika to the vet to be spayed, ensuring that no unplanned puppies wind up on the streets. She also showers them with affection — as she does with all furry visitors who drop by.

“We feed all the dogs that come to our business looking for food, regardless of whether they have a home or not, because we don’t know,” the owner said. “This is truly work we do from the heart.”

Earlier this month, astronomers noticed a mysterious object speeding toward the inner solar system from outside of our star system.

It’s an exceedingly rare occurrence, marking only the third confirmed interstellar object to have ventured into our solar system, all of which have been detected since 2017.

Harvard astronomer and alien hunter Avi Loeb was quick to raise the tantalizing — albeit admittedly far-fetched — possibility that the object, dubbed 3I/ATLAS, could have been an alien probe sent to us by an intelligent civilization.

And now, in a twist right out of Stanley Kubrick’s 1968 “2001: A Space Odyssey,” he’s suggesting a way that we could use an existing spacecraft to intercept the object’s path to test that very hypothesis.

In a yet-to-be-peer-reviewed paper, the researcher argued that NASA’s Juno spacecraft, which was designed to study Jupiter and launched in 2011, could get eerily close to 3I/ATLAS by March 14, 2026.

Juno would have to apply a thrust of 1.66 miles per second on September 14, 2025, Loeb calculated, to intercept the mysterious object’s path.

“The close encounter of 3I/ATLAS to Jupiter provides a rare opportunity to shift Juno from its current orbit around Jupiter to intercept the path of 3I/ATLAS at its closest approach to Jupiter,” he wrote in a new blog post about the proposal.

While it’s technically not a rendezvous — the object’s “excessively high hyperbolic speed” wouldn’t allow for such a meeting — Juno’s arsenal of scientific instruments “can all be used to probe the nature of 3I/ATLAS from a close distance,” Loeb argued.

Whether the spacecraft, which has been soaring through space for 14 years now, would have enough fuel to even pull off such a stunt remains unclear.

But Loeb argues it could “rejuvenate Juno’s mission and extend its scientific lifespan beyond” the potential intercept some eight months from now.

The news comes as scientists are still racing to get a better sense of 3I/ATLAS’ exact nature. Last week, the recently inaugurated Vera C. Rubin Observatory in Chile had a closer look, finding that the object is roughly seven miles wide, making it the largest interstellar object ever spotted.

The prevailing and most widely accepted theory suggests that 3I/ATLAS is a comet, with previous observations supporting the idea that its coma, or surrounding cloud of ice, dust, and gas, was anywhere up to 15 miles across.

The Vera C. Rubin observations identified large amounts of dust and water ice surrounding its solid nucleus, as detailed in a July 17 preprint, further adding evidence that it’s a comet.

Yet many questions surrounding its origin remain a mystery. Some researchers believe it came from our galaxy’s “thick disk,” a dense layer that features chemically distinct populations of stars.

Other researchers suggest it could be around three to 11 billion years old, dating it back to the earliest days of the Milky Way.

It seems unlikely that NASA will find Loeb’s suggestion compelling enough to fire up Juno’s thrusters for an intercept. But it’s an extremely rare opportunity to finally get a close glimpse of an interstellar visitor nonetheless — so hopefully they’re at least checking his math to see if it’s possible.

More on 3I/ATLAS: Scientist Suggests Tests to See if Large Object Headed Toward Earth Could Be an Alien Spacecraft

How are nuclear weapons maintained and modernised in the 21st century? America stopped explosively testing its warheads and bombs in 1992. Now the country relies on sophisticated computer simulations and energetic lasers to understand how these devices work and to keep them safe as they age. For the first time ever, America’s nuclear scientists are also having to design a brand new warhead using simulations alone.

This four-part series traces the scientific story of nuclear weapons. We go behind the scenes at America’s nuclear-weapons laboratories to find out how the country is pushing the frontiers of extreme physics, materials science and computing to modernise its stockpile.

NASA astronaut Kathleen “Kate” Rubins has retired from the space agency after 16 years, two missions on the International Space Station, four spacewalks and 300 days in space. Her last day at Johnson Space Center (JSC) in Houston was Monday (July 28).

In August 2016, while serving as a flight engineer on the space station’s 48th expedition crew, Rubins made history by using a USB-powered portable device called MinION to sequence the DNA from a mouse, bacteria and a virus. It was the first time that DNA sequencing had been conducted in the microgravity environment of space.

“From her groundbreaking work in space to her leadership on the ground, Kate has brought passion and excellence to everything she’s done,” said Joe Acaba, chief of the Astronaut Office at JSC, in a statement. “She’s been an incredible teammate and role model. We will miss her deeply, but her impact will continue to inspire.”

In addition to her DNA work, Rubins’ first spaceflight also included the test of an upgraded Russian Soyuz spacecraft (Soyuz MS-01), as well as 275 other science investigations ranging from cell cultures to fluid dynamics. She also conducted her first two spacewalks; together with fellow NASA astronaut Jeff Williams, Rubins helped install the first of two international docking adapters (IDAs) and retracted a thermal radiator.