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When white dwarfs—the hot remnants of stars like our Sun—are orbited closely by another star, they sometimes steal mass away from their companion. The stolen matter builds up on the surface of the white dwarf, triggering eruptions called novae.

Theorists have long predicted how these volatile partnerships, called cataclysmic variables (CVs), form, but now a new Caltech-led study reveals a surprising twist: In some cases, a third star, circling farther away from the primary pair, may in fact be the reason the star couple got together in the first place.

“Our results are revealing another formation channel for CVs,” says Kareem El-Badry, assistant professor of astronomy at Caltech and a co-author of a new paper appearing in the Publications of the Astronomical Society of the Pacific. “Sometimes, a lurking third star is key,” he says. The lead author of the study is Caltech graduate student Cheyanne Shariat.

Before now, scientists believed that CVs formed from a process called common envelope evolution, in which the partner stars are brought closer together via an envelope of gas that cocoons them. An aging star destined to become a white dwarf expands into a red giant that encompasses both stars, creating a shared envelope. The envelope corrals the two stars, causing them to spiral inward. Eventually, the envelope is ejected, leaving a tight pair that have become close enough for the white dwarf to steal its companion’s mass.

Although a third star was not mentioned in these descriptions, the team wondered if one could be involved. After all, they reasoned, triple-star dynamics do play a role in other types of star systems.

To further investigate the matter, the researchers turned to data from the European Space Agency’s Gaia mission, now retired. Sorting through these observations, they identified 50 CVs in hierarchical triple-star systems, or triples, as the researchers call them. A hierarchical triple is one in which two stars are located fairly close together, while the third is much farther out and orbits the primary pair. The results suggested that at least 10 percent of all known CVs are part of triple systems.

That 10 percent number was higher than what would be expected if triples had no role in CV formation, so the researchers decided to learn more by running computer simulations. They performed so-called three-body simulations on 2,000 hypothetical triples; these simulations sped up the gravitational interactions of the trio of stars, evolving them over time.

In the triple-star simulations, CVs formed without the traditional mechanism of common envelope evolution 20 percent of the time. In these cases, the researchers say, the third star torqued the main binary.

“The gravity of the third star causes the binary stars to have a super eccentric orbit, and this forces the companion star closer to the white dwarf. Tidal forces dissipate energy and shrink and circularize the orbit,” Shariat says. “The star doesn’t have to spiral in through the common envelope.”

In 60 percent of the simulations, the triple star helped initiate the process of common envelope evolution, bringing the two primary stars close enough to one another to be encased in the same envelope. In the remaining 20 percent of the simulations, the CVs formed via the traditional common envelope evolution route that requires just two stars.

When the researchers accounted for a realistic population of stars in our galaxy, including CVs known to have formed from just two stars, their theoretical models predicted around 40 percent of all CVs form in triple systems. This is higher than the 10 percent they observed using Gaia because, in many cases, the third stars can be either hard to see or have become unbound from the CV.

Finally, the simulation results enabled predictions about the types of triple-star systems that would be more likely to form CVs. Specifically, the triple systems would be expected to start out in wider configurations, such that the tight-knit pair and the third star are separated by more than 100 astronomical units (an astronomical unit, or au, is the distance between the Sun and Earth).

Looking back at the Gaia data, the researchers found agreement: The triples with CVs did exhibit wider separations on average than typical systems.

“For the past 50 years, people were using the spiral-in common-envelope evolution model to explain CV formation,” El-Badry says. “Nobody had noticed before that this was largely happening in triples!”

The study titled “Cataclysmic Variables in Triples: Formation Models and New Discoveries” was funded by the Joshua and Beth Friedman Foundation Fund, NASA, the National Science Foundation, and Howard and Astrid Preston. The project was done in collaboration with Smadar Naoz, a researcher at UCLA who specializes in theoretical studies of triples. Other authors include Antonio Rodriguez, a graduate student at Caltech, and Jan van Roestel of the University of Amsterdam.

“I believe this highlights the incredible defensive traits some animals have,” said study author and Assistant Professor at Florida International University, Yannis Papastamatiou, to IFLScience. “A lot of defensive traits appear ineffective against big predators (e.g. large sharks eat stingrays often; the barb doesn’t seem to deter them). At least from our limited observations, electric rays may be very effective at deterring large predators.”

It paints the picture of a highly effective defensive mechanism!

Yannis Papastamatiou

The team hadn’t set out to uncover the zapping tendencies of rays around the island. They were deploying camera tags on white sharks, intending to study their social hunting, but once they spotted what was going on, they (too) were stunned.

“I was so surprised I waited until there was more evidence, which we got when we saw the tiger shark footage,” said Papastamatiou. “When taken in combination with other observations, like their boldness in the water, it paints the picture of a highly effective defensive mechanism!”

Rays are more typically associated with defensive strategies like camouflage (some look like sandy pancakes), venom and barbs (hello stingrays), and spines that make them a less swallowable meal (though some get used as scratching posts), but as Papastamatiou highlighted, these rarely stop big sharks from eating them. Now, it appears that one group of rays has found a way to thrive in dangerous waters by sending out electric discharges to any sharks that get too close.

The rays here occupy a high position in the water column, which is about as dangerous as it gets when it comes to the ocean. There are an estimated 69 species of electric rays belonging to four separate families, all equipped with electric organ discharge (EOD) that in some of the larger species can go up to 50 volts. We didn’t know exactly how they were deploying that talent, however, until now.

Case study one, included in a new paper about the behavior, details the deployment of Customized Animal Tracking Solutions (CATS) biologgers attached to white sharks that revealed some intriguing data. One shark taking a casual cruise at 50 meters (164 feet) depth approached an electric ray in the midwater before suddenly ascending to 30 meters (100 feet). Two minutes later, it returned to the previous depth, but gave the ray a wide berth. The ray itself seemed totally unfazed by the entire episode, carrying on with its business like only a badass can.

          

Another case study included a shark that was captured on camera getting done in by the Gulf torpedo ray’s not-so-secret weapon. It was a tiger shark approaching a ray in Fuvahmulah, Maldives, only to whip out its nictitating membrane as it got near. Also known as the “third eyelid”, these membranes are deployed as a defensive strategy to shield the eye from harm.

The third case study looked at the electrical discharges produced by Pacific electric rays during field experiments off Palos Verdes, California. The rays were provoked into discharging defensive and predatory shocks to see how they differed, and the results showed that while they didn’t vary in maximum voltage, predatory shocks were longer and more abundant.

The study provides fresh insights into the evolution of defensive traits in marine animals, and it’s hoped that further study using biologging set ups could lift the lid on exactly what gives these rays so much damn confidence. “We still have so much to learn!” Papastamatiou said.

The study is published in Ethology.

In a comprehensive Genomic Press Interview published in Brain Medicine, Dr. Michael C. Oldham shares his unconventional journey from advertising executive to computational neuroscientist and his groundbreaking contributions to understanding the human brain’s cellular and molecular architecture through gene coexpression analysis.

From Madison Avenue to molecular neuroscience

Dr. Oldham’s path to neuroscience was anything but direct. After graduating from Duke University at age 20 with a pre-med focus, he found himself unable to commit to medical school, recognizing he lacked the intrinsic desire to treat patients. Following a stint in San Francisco’s advertising industry during the dot-com boom, his fascination with human language evolution and what distinguishes human brains from those of our closest primate relatives led him back to academia.

“The genetic changes that gave rise to the modern human brain were the catalyst for life as we know it,” Dr. Oldham reflects in the interview. This fundamental question drove him to pursue a PhD at UCLA, where he would make discoveries that continue to shape neuroscience research today.

Pioneering gene coexpression network analysis

Working with Dr. Dan Geschwind at UCLA and biostatistician Dr. Steve Horvath, Dr. Oldham performed the first genome-wide analysis of transcriptional covariation in the human brain. His eureka moment came when he realized that recurrent patterns of gene activity in brain samples corresponded to transcriptional signatures of different cell types.

“Variation in the cellular composition of bulk tissue samples should inevitably drive the covariation of markers for different cell types,” Dr. Oldham explains. This insight, published in Nature Neuroscience in 2008, demonstrated how gene coexpression analysis could reveal optimal markers of cell types and states-a principle that still forms the central thesis for his laboratory at UCSF.

The approach, known as Weighted Gene Coexpression Network Analysis (WGCNA), has become a cornerstone technique in genomics research. Unlike traditional differential expression analysis that compares individual genes between cohorts, WGCNA identifies robust patterns of coordinated gene activity within biological systems. This methodology has proven particularly powerful for understanding complex tissues like the brain, where multiple cell types interact in intricate ways.

From brain evolution to brain tumors

Dr. Oldham’s early research focused on analyzing patterns of gene activity in the brains of humans and other species. These efforts identified functionally significant gene expression changes in human radial glia (Nature, 2014), interneurons (Cerebral Cortex, 2018), and astrocytes (Nature Neuroscience, 2018), while introducing novel methods for aggregating and comparing patterns of gene activity among biological systems.

More recently, his research focus has shifted from studying what makes human brains unique to tackling one of medicine’s most challenging diseases: malignant gliomas. As a faculty member in UCSF’s Department of Neurological Surgery and Brain Tumor Center, he applies his computational approaches to these notoriously heterogeneous brain tumors.

His team has analyzed gene activity patterns from over 17,000 human brain samples, including approximately 10,000 normal and 7,000 malignant glioma samples. This massive undertaking has led to the development of OMICON (theomicon.ucsf.edu), a platform designed to make the patterns of gene activity in these complex datasets accessible to the broader research community. The resource contains over 100,000 gene coexpression modules that have been extensively characterized via enrichment analysis with thousands of curated gene sets, providing researchers worldwide with unprecedented insights into brain function and dysfunction.

By comparing patterns of gene activity between normal human brains and malignant gliomas, Dr. Oldham and his team are pinpointing highly reproducible molecular changes in specific cell types of the glioma microenvironment, including vascular cells and neurons. These molecular signatures provide opportunities for developing novel biomarkers and targeted treatment strategies for glioma patients. For example, cell-surface markers of glioma vasculature provide a potential molecular ‘zip code’ for targeting gliomas via the bloodstream.

Confronting the reproducibility crisis

Beyond his primary research, Dr. Oldham has become increasingly concerned with what he describes as science’s reproducibility crisis. “If most of the findings we toil to produce cannot feasibly be reproduced, what is the point?” he asks, highlighting a challenge that extends far beyond neuroscience.

His response has been to take leadership roles addressing these systemic issues. As Vice Chair of UCSF’s Academic Senate Committee on Library and Scholarly Communication, he has launched a pan-UCSF Task Force on research data and metadata standardization. While the topic might sound technical, Dr. Oldham emphasizes its critical importance: these standards are essential prerequisites for more open and reproducible science, more precise biomedical knowledge representation, and more efficient collaboration.

“Although there are many factors that affect the reproducibility of published research findings, there is no reason in principle why data analysis should not be completely reproducible,” Dr. Oldham notes. “By standardizing how we package and describe our research data, we can accelerate data discovery and analysis, including the use of artificial intelligence. More generally, standardized data packages with persistent identifiers can serve as building blocks for new technology infrastructure to modernize scholarly communication around reproducible data analysis.”

The human side of scientific discovery

The interview reveals personal insights that shaped Dr. Oldham’s career trajectory. His decision to spend two additional years in graduate school after his first major publication-a choice some considered “nuts”-resulted in a second, even more impactful paper that secured his selection as a UCSF Sandler Faculty Fellow. This prestigious position provided him with immediate independence and funding to establish his own laboratory.

When not advancing neuroscience, Dr. Oldham can be found on the trails of Marin County, where he lives, often walking alone and lost in thought. He maintains close friendships from his San Francisco advertising days, adhering to their motto: “ABC (always be celebrating!).”

Looking ahead, Dr. Oldham sees the integration of multiscale and multimodal data as crucial for understanding brain complexity. He advocates for standardized data production strategies that leverage robotic automation to generate reproducible datasets at scale. Dr. Oldham also believes that neuroscientists must ‘flip the switch’ from descriptive analysis of biological systems to predictive analysis using statistical models. “There is a big difference between describing what you think a dataset means versus predicting what you will see in the next dataset,” he says.

Dr. Michael C. Oldham’s Genomic Press interview is part of a larger series called Innovators & Ideas that highlights the people behind today’s most influential scientific breakthroughs. Each interview in the series offers a blend of cutting-edge research and personal reflections, providing readers with a comprehensive view of the scientists shaping the future. By combining a focus on professional achievements with personal insights, this interview style invites a richer narrative that both engages and educates readers. This format provides an ideal starting point for profiles that explore the scientist’s impact on the field, while also touching on broader human themes. More information on the research leaders and rising stars featured in our Innovators & Ideas – Genomic Press Interview series can be found in our publications website: https://genomicpress.kglmeridian.com/.

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In a discovery that could reshape approaches to regenerative medicine and bone repair, researchers have found that human stem cells can be prompted to begin turning into bone cells simply by squeezing through narrow spaces.

The study suggests that the physical act of moving through tight, confining spaces, like those between tissues, can influence how stem cells develop. This could open new possibilities for engineering materials and therapies by guiding cell behaviour using physical, rather than chemical, signals.

The research was led by Assistant Professor Andrew Holle (Biomedical Engineering and the NUS Mechanobiology Institute) and was published on 8 May 2025 in the journal Advanced Science.

Asst Prof Holle leads the Confinement Mechanobiology Lab at NUS. His lab studies how physical constraints – especially the tight spaces cells encounter as they move – affect how cells behave, function, and develop. While most earlier research in this area focused on cancer and immune cells, his team is among the first to explore how these forces affect stem cells, with the aim of applying their findings to future therapies.

Mechanical ‘memory’

The researchers focused on a type of adult stem cell known as a mesenchymal stem cell, or MSC. These cells are found in bone marrow and other tissues and are known for their ability to develop into bone, cartilage, and fat cells. Because of these properties, MSCs are widely used in research on tissue repair and regeneration.

“To test how physical forces influence stem cell fate, we developed a specialised microchannel system that mimics the narrow tissue spaces cells navigate in the body,” said Asst Prof Holle.

They found that when MSCs squeezed through the smallest channels (just three micrometres wide), the pressure caused lasting changes to the cells’ shape and structure. These cells showed increased activity in a gene called RUNX2, which plays a key role in bone formation. Even after exiting the channels, they retained this effect – suggesting they carry a kind of mechanical ‘memory’ of the experience.

“Most people think of stem cell fate as being determined by chemical signals,” Asst Prof Holle said. “What our study shows is that physical confinement alone – squeezing through tight spaces – can also be a powerful trigger for differentiation.”

While traditional methods of directing stem cells rely on chemical cues or growing them on stiff or soft materials, Asst Prof Holle’s team believes confinement-based selection may offer a simpler, cheaper, and potentially safer alternative. “This method requires no chemicals or genetic modification – just a maze for the cells to crawl through,” he said. “In theory, you could scale it up to collect millions of preconditioned cells for therapeutic use.”

The researchers say their findings could help improve the design of biomaterials and scaffolds used in bone repair, by creating physical environments that naturally encourage the right kind of cell development. “By tuning the mechanical properties of materials, we might be able to steer stem cells more reliably toward the cell types we want,” Asst Prof Holle said.

Next steps

The approach could one day be used to speed up recovery from bone fractures or enhance the effectiveness of stem cell therapies. “We’d like to test whether preconditioned cells that have gone through this mechanical selection are better at promoting healing when introduced at injury sites,” Asst Prof Holle said. “That’s one of the next steps.”

Beyond bone repair, the research may have broader implications. MSCs are also known to migrate toward tumours, and the research team is interested in whether mechanically preconditioned cells might be better equipped to move through dense tumour tissue – a challenge that has limited the success of many current cell therapies.

The group is also exploring whether the technique could apply to more potent stem cell types, such as induced pluripotent stem cells (iPSCs), which can develop into almost any tissue in the body.

“We suspect that confinement plays a role even in embryonic development,” Asst Prof Holle said. “Cells migrating through crowded environments early in life are exposed to mechanical stress that could shape their fate. We think this idea has potential far beyond just MSCs.”

Reference: Gao X, Li Y, Lee JWN, et al. Confined migration drives stem cell differentiation. Adv Sci. 2025;12(21):2415407. doi: 10.1002/advs.202415407

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In 2022, the underwater Hunga volcano exploded, blasting ash 37 miles into the sky – the largest volcanic plume ever captured by satellites. What followed offered researchers a rare chance to see how the ocean floor responds to sudden, massive disruption.

Months later, scientists from the University of Oregon, along with teams from the University of Rhode Island and Western Washington University, headed out on a research cruise.

Onboard, undergraduate student Marcus Chaknova discovered something unexpected: thick layers of volcanic ash coating the seafloor. The ash had suffocated deep-sea ecosystems that rely on fragile chemical exchanges to survive.

Underwater eruptions usually go unseen

“This was an extremely rare opportunity,” Chaknova said. “Observing the mass movement of underwater sediment is something that hasn’t been studied much.”

Now a graduate student in Earth Sciences at the University of Oregon, Chaknova led a research project analyzing what the underwater eruption left behind.

Working with Professor Thomas Giachetti and 16 other experts from around the world, he became the lead author on a study that looked at how volcanic ash travels – and what it does to life underwater.

“We had scientists from every single time zone you could think of,” Chaknova said. His project needed expertise from the fields of marine biology, geochemistry, and micropaleontology.

Tracking ash from the volcano

The first step was to confirm that the underwater ash had indeed come from Hunga, located about 40 miles from Tonga’s main island in the South Pacific.

After an eruption, it can take weeks or even months for ash to fall through the water and settle on the ocean floor. As it drifts, wind and currents push it farther from the eruption site.

“One grain of sediment will take weeks or months to reach the bottom of the ocean. It’s like a leaf falling from a tree. Because of the wind, it might end up somewhere completely different,” Giachetti explained.

Back in the lab, Chaknova matched the ash samples to those found near the volcano. The grains were varied – some jagged and sharp, others rounded and smooth.

In some places, the sediment was more than a meter thick. Most of it was made up of very fine particles, around the width of a human hair.

What the eruption left behind

Chaknova discovered that much of the ash came from the volcano’s caldera walls and was carried away by fast-moving underwater flows – something like underwater avalanches.

Those flows were so powerful they damaged submarine cables and carved small canyons into the seafloor. The researchers even used the timing of power loss from those broken cables to calculate how fast the ash surged.

Using computer models, Chaknova plans to simulate how the ash moved and where it went. Giachetti said this research could change how scientists think about sediment movement in the oceans.

Deep-sea life suffocated

The underwater eruption didn’t just leave a geological footprint. It disrupted entire ecosystems.

In the deep sea, where sunlight doesn’t reach, life depends on chemosynthesis – organisms use chemicals like methane or ammonia from hydrothermal vents, instead of sunlight, to produce energy.

Roughly 90% of marine life lives on the seafloor, according to the World Wide Fund for Nature. After the eruption, much of that life was buried in thick sediment.

Some creatures like worms and anemones can survive brief burials, but this sudden wave of ash was too much. Many deep-sea species are suspension feeders. They grab tiny particles of food from the water and filter them through their gills.

“With all the displaced sediment, these organisms are only grabbing sediment,” Chaknova said. “That’s going to clog their gills, it’s going to clog their intestines, and that’s going to have a dramatic effect on their ability to create energy.”

Fallout from the underwater eruption

Chaknova’s early findings also show that ash made it all the way to Tonga’s coral reefs. At first, it caused a short-lived plankton bloom at the surface.

But as the ash settled, it threatened coral ecosystems that support larger marine life. When coral suffers, everything above it in the food chain is affected.

For Tonga, the eruption of this underwater volcano had more than environmental consequences. It also affected livelihoods.

Fishing is a way of life in Tonga. According to the World Bank, about 82% of households rely on reef fishing in some way for income. Marine tourism accounts for more than 7% of Tonga’s GDP.

“Although this eruption occurred on the seafloor, there is a chain of both positive and negative effects,” Chaknova said.

“The negative effects go farther than just losing power or Wi-Fi from submarine cables. This is some people’s livelihood. They need fish for food. Fishing is incredibly important for the economic and food security of Tonga.”

A warning for deep-sea mining

The study also has bigger implications. As the world turns toward clean energy, demand is growing for metals like copper and cobalt – many of which sit in potato-sized nodules beneath the ocean floor.

Private companies have approached small Pacific nations, including Tonga, with offers to mine these resources.

“The area where we collected the sediment is within the Kingdom of Tonga, and we found that they are very rich in minerals,” Chaknova said. “A lot of companies are interested in collecting these minerals, and so this area that belongs to the Kingdom of Tonga will be up for bid, in coming years, for deep-sea mining.”

While commercial mining hasn’t started yet, researchers are urging caution. The plumes of sediment created by mining could be just as harmful as those created by volcanic eruptions – clogging gills, burying habitats, and destroying fragile ecosystems.

Chaknova’s work provides some of the only real-world data we have on what that kind of disturbance could look like.

The research gives scientists and policymakers a better understanding of what’s at stake – and what might be lost if we move forward without enough knowledge.

The full study was published in the journal Geochemistry, Geophysics, Geosystems.

Image Credit: NOAA

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The Prince’s Palace is transforming its prestigious Car Collection into a portal to infinity, playing host to four futuristic rovers that redefine the boundaries between terrestrial motoring and space exploration.

Until 2 September, visitors to the Car Collection of H.S.H. the Prince of Monaco can contemplate humanity’s future via four exceptional rover vehicles, the fruits of a joint venture between Venturi Space and Venturi Astrolab. The temporary exhibition transforms the showcase for prestigious cars into a space innovation laboratory, where each rover tells a story of interplanetary conquest.

Flex: lunar ambassador for 2027

The Flex astromobile, the jewel in the crown of the ephemeral collection, is preparing to set foot, or rather wheel, on the moon in 2027 via SpaceX. Shortlisted by NASA, this technological marvel features Monegasque innovations: hyper-deformable wheels designed in Switzerland and high-performance batteries developed in the Principality.

© Michael Alesi / Prince’s Palace

From the Moon to Mars: unlimited ambition

The Flip rover will reach the lunar South Pole in 2026, while its Martian counterpart will pave the way for colonisation of the Red Planet. Mona Luna embodies European excellence, with a Franco-Monegasque design for the European Space Agency and CNES, France’s national space study centre.

Venturi Space: electric meets cosmic

Under the visionary leadership of Gildo Pastor, Venturi started a strategic revolution in 2021, shifting its focus from terrestrial automotive innovation to the space industry. This metamorphosis is a perfect illustration of Monegasque DNA: transforming boldness into excellence, and innovation into legend.

Venturi Space welcomes Prince Albert II for exclusive visit

The unique exhibition reveals how Monaco, a Principality with a limited terrestrial footprint, nurtures infinite ambitions, writing the first pages of European space history.

Prince of Monaco’s Car Collection, 54 route de la Piscine – Port Hercule.

SpaceX launched 28 more Starlink satellites for its low Earth orbit constellation on Tuesday (July 8).

A Falcon 9 rocket lifted off with the broadband internet units (Group 10-28) at 4:21 a.m. EDT (0821 GMT) from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida. About nine minutes later, the satellites reached space and, 50 minutes after that, were deployed into orbit.

“Deployment of 28 Starlink satellites confirmed,” SpaceX announced on the X social media network.

In a cosmic twist worthy of a sci-fi thriller, astronomers have just caught a massive star in the act of dying, not with a bang, but with a stifled X-ray-powered whisper.

Using a global network of telescopes, including the International Gemini Observatory and the SOAR Telescope in Chile, astronomers have observed the closest-ever example of a mysterious cosmic event called a fast X-ray transient (FXT). This particular flash, named EP 250108a, was spotted in January 2025 by the newly launched Einstein Probe, and it’s helping astronomers rewrite the story of how stars die.

FXTs are brief, powerful bursts of X-rays from distant galaxies that last just seconds to hours. They’ve puzzled astronomers for years, until now. EP 250108a, located a mere 2.8 billion light-years away (close by cosmic standards), gave scientists their best look yet.

Once the Einstein Probe raised the alarm, telescopes around the world sprang into action. Gemini South’s FLAMINGOS-2 and Gemini North’s GMOS captured the event in infrared and optical light, revealing the glowing aftermath of a supernova.

Researchers detected the brightest gamma-ray burst

But this wasn’t your typical supernova. Instead of blasting jets of energy into space like a gamma-ray burst (GRB), this star’s jets got stuck inside, heating up the star’s outer layers and releasing X-rays in the process. Think of it as a cosmic pressure cooker.

“This FXT supernova is nearly a twin of past supernovae that followed GRBs,” said Rob Eyles-Ferris, lead author of one of two companion studies. “But here, the jets failed to escape.”

That failure turned out to be a scientific jackpot. By watching the event unfold over days and weeks, astronomers confirmed that the FXT was tied to a Type Ic broad-lined supernova, SN 2025kg, likely from a star 15–30 times the mass of our Sun.

“The X-ray data alone cannot tell us what phenomena created the FXT,” says Jillian Rastinejad, PhD student at Northwestern University and lead author of the second companion paper. “Our optical monitoring campaign of EP 250108a was key to identifying the aftermath of the FXT and assembling the clues to its origin.”

It takes two stars to make a gamma-ray burst

After the initial X-ray flash from EP 250108a, astronomers noticed the area getting brighter in optical light for a few weeks before fading. The light also showed special patterns, called broad absorption lines, that revealed the FXT was linked to a powerful kind of explosion known as a Type Ic broad-lined supernova.

To learn more, the team used the SOAR Telescope in Chile to observe the event in near-infrared light. These observations helped them estimate how bright the explosion got and what kind of star caused it.

Their best guess? A massive star weighing 15 to 30 times more than our Sun, a true cosmic heavyweight that ended its life with a dramatic if slightly muffled, bang

“Our analysis shows definitively that FXTs can originate from the explosive death of a massive star,” says Rastinejad. “It also supports a causal link between GRB-supernovae and FXT-supernovae, in which GRBs are produced by successful jets and FXTs are produced by trapped or weak jets.”

A super-bright stellar explosion gave birth to a compact object

FXTs are now being detected several times a month, while GRBs are rare, only about once a year. This suggests that “failed” jet explosions like EP 250108a may be far more common than their flashier cousins.

“This discovery opens a new window into how massive stars die,” said Jillian Rastinejad, co-author of the second study. “It shows that even when a star’s final act is muted, it still has a powerful story to tell.”

With the upcoming Vera C. Rubin Observatory set to launch its Legacy Survey of Space and Time, astronomers expect to uncover even more of these hidden stellar dramas. And thanks to the rapid-response power of observatories like Gemini, we’ll be ready to catch them in the act.

Journal References:

1. Rob A. J. Eyles-Ferris, Peter G. Jonker, Andrew J. Levan, Daniele Bjørn Malesani, Nikhil Sarin, Christopher L. Fryer, Jillian C. Rastinejad, Eric Burns, Nial R. Tanvir, Paul T. O’Brien, Wen-fai Fong, Ilya Mandel, Benjamin P. Gompertz, Charles D. Kilpatrick, Steven Bloemen, Joe S. Bright, Francesco Carotenuto, Gregory Corcoran, Laura Cotter, Paul J. Groot, Luca Izzo, Tanmoy Laskar, Antonio Martin-Carrillo, Jesse Palmerio, Maria E. Ravasio, Jan van Roestel, Andrea Saccardi, Rhaana L. C. Starling, Aishwarya Linesh Thakur, Susanna D. Vergani, Paul M. Vreeswijk, Franz E. Bauer, Sergio Campana, Jennifer A. Chacón, Ashley A. Chrimes, Stefano Covino, Joyce N. D. van Dalen, Valerio D’Elia, Massimiliano De Pasquale, Nusrin Habeeb, Dieter H. Hartmann, Agnes P. C. van Hoof, Páll Jakobsson, Yashaswi Julakanti, Giorgos Leloudas, Daniel Mata Sánchez, Christopher J. Nixon, Daniëlle L. A. Pieterse, Giavanna Pugliese, Jonathan Quirola-Vásquez, Ben C. Rayson, Ruben Salvaterra, Ben Schneider, Manuel A. P. Torres, Tayyaba Zafar. The kangaroo’s first hop: the early fast cooling phase of EP250108a/SN 2025kg. The Astrophysical Journal Letters. DOI: 10.48550/arXiv.2504.08886
2. J. C. Rastinejad (Northwestern), A. J. Levan, P. G. Jonker, C. D. Kilpatrick, C. L. Fryer, N. Sarin, B. P. Gompertz, C. Liu, R. A. J. Eyles-Ferris, W. Fong, E. Burns, J. H. Gillanders, I. Mandel, D. B. Malesani, P. T. O’Brien, N. R. Tanvir, K. Ackley, A. Aryan, F. E. Bauer, S. Bloemen, T. de Boer, C. R. Bom, J. A. Chacon, K. Chambers, T.-W. Chen, A. A. Chrimes, J. N. D. van Dalen, V. D’Elia, M. De Pasquale, M. D. Fulton, P. J. Groot, R. Gupta, D. H. Hartmann, A. P. C. van Hoof, M. E. Huber, L. Izzo, W. Jacobson-Galan, P. Jakobsson, A. Kong, T. Laskar, T. B. Lowe, E. A. Magnier, E. Maiorano, A. Martin-Carrillo, L. Mas-Ribas, D. Mata Sanchez, M. Nicholl, C. J. Nixon, S. R. Oates, G. Paek, J. Palmerio, D. Paris, D. L. A. Pieterse, G. Pugliese, J. A. Quirola Vasquez, J. van Roestel, A. Rossi, A. Rouco Escorial. R. Salvaterra, B. Schneider, S. J. Smartt, K. Smith, I. A. Smith, S. Srivastav, M. A. P. Torres, C. Ventura, P. Vreeswijk, R. Wainscoat, Y.-J. Yang, S. Yang. EP 250108a/SN 2025kg: Observations of the most nearby Broad-Line Type Ic Supernova following an Einstein Probe Fast X-ray Transient. Astrophysical Journal Letters. DOI: 10.48550/arXiv.2504.08889

Scientists in Finland and Germany have developed a new kind of nanostructure that mimics the scattering and absorptive properties of clouds to either cool or heat objects exposed to sunlight (Adv. Mater., doi: 10.1002/adma.202501080). They say that the structure’s low emissions at infrared wavelengths make it well suited to military and materials applications requiring invisibility to thermal imaging.

Passive cooling

Objects can be passively cooled by shielding them from solar radiation and insulating them from their environment while enhancing emission at infrared wavelengths, allowing heat to be transferred from the objects to the cold of outer space. However, this infrared emission renders such objects susceptible to thermal imaging. (White paints, which scatter light diffusely across all wavelengths, also emit significant thermal radiation.)

An alternative approach to passive cooling is to exploit the thermal physics of white clouds. These clouds cool air via backscattering—scattering incoming sunlight back in the direction it came from. Because they do so across a broad range of visible and infrared wavelengths, the clouds avoid heating up and emitting thermal radiation. Conversely, when clouds are located underneath a layer of aerosols, their backscattered light is absorbed by the particles, turning the clouds gray and heating the air around them.

In the latest work, Mady Elbahri, Aalto University, Finland, and colleagues have taken inspiration from these processes to develop plasmonic metasurfaces that can modify both the optical and thermal properties of materials exposed to the sun’s rays. Their idea was to tailor the characteristics of silver nanoparticles lying on a substrate so that they backscatter light across visible and near-infrared wavelengths.

Mimicking clouds

The researchers fabricated a metasurface to mimic a white cloud by first depositing a very thin film of silver onto a layer of silicon and then carrying out vacuum annealing at 650ºC for 50 minutes. After producing a certain size and distribution of silver islands atop the silicon, they deposited a thicker (120-nm-thick) layer of silver on top of that. This upper reflecting layer not only made the surface more stable, it also converted what would otherwise have been forward-scattered light into back-scattered light.

Elbahri and colleagues found that they could control the size of the silver nanoparticles by varying the thickness of the initial film. Thicker films yielded bigger and more varied particles, which pushed backscattering to longer wavelengths. With 50-nm-thick films, the team achieved backscattering across much of the visible and near-infrared spectrum, preventing heat from building up and so minimizing emissions in the infrared.

To reproduce the effects of a gray cloud, the scientists then deposited a plasmonic nanocomposite—an aluminium oxide matrix containing randomly distributed copper nanoparticles acting like aerosols—on top of the existing metasurface. This extra layer absorbed almost all of the light backscattered by the silver, changing the device’s original white color to gray.

To confirm that their metasurface switched from mimicking white to gray clouds, the researchers placed the device on a block of foam, exposed it to simulated sunlight and measured its temperature with a thermocouple. They found that without the nanocomposite, their metasurface reduced the temperature of the underlying substrate by 10ºC. With the additional layer added, in contrast, the metasurface increased the relative temperature by 10ºC—even surpassing the absorptive capacity of black surfaces.

Toward energy efficiency and beyond

Elbahri and colleagues argue that their technology could be exploited in adaptive coatings for energy efficiency in buildings, solar systems and textiles, as well as for military thermal camouflage. Having already fabricated different samples to demonstrate the mimicking of white and gray clouds, they say their next step is to build a device that can switch between the two states using, for example, electrochromic or phase-changing layers.

They add that while the scattering efficiency of the white sample dropped slightly after remaining in storage, that of the gray sample remained almost unchanged; demonstrating, they say, “the metasurfaces’ practical stability for consumer applications.”