Category: 7. Science

  • Australian researchers refine spray technology to help shield endangered coral reefs-Xinhua

    SYDNEY, Aug. 27 (Xinhua) — Australian researchers have unlocked new insights to create tiny seawater droplets to form mist plumes that reflect sunlight to protect coral reefs.

    Modelling in high resolution revealed how a high-pressure spray system splits sun-reflecting seawater droplets, which offers new insights to optimize seawater fogging technology to shield coral from bleaching, according to a statement released Wednesday by Australia’s Queensland University of Technology (QUT).

    “Our findings provide a deeper understanding of how these fine droplets form, move, and change in size after being sprayed,” said the study’s first author, QUT researcher Saima Bukhat Khan.

    The QUT team, working with Australia’s Southern Cross University’s National Marine Science Center, focused on “secondary droplet break up,” a process in which already formed droplets continue to fragment into smaller ones.

    This new finding could enhance the high-pressure spray systems used by the Reef Restoration and Adaptation Program (RRAP)’s Cooling and Shading team to generate a dense seawater mist that shields high-priority reefs during sweltering calm weather with the greatest coral bleaching risk, Khan said.

    The research combined wind tunnel experiments with computer modelling to analyze how filtered seawater droplets behave when sprayed through specialized “impaction-pin” nozzles, she said.

    These experiments and simulations enabled precise modelling of droplet sizes and spray patterns, guiding improved nozzle and spraying system designs for environmental applications, she added.

    The findings, published in the Journal of Aerosol Science, could also benefit agriculture, medicine and industrial settings, the researchers said.

    The research was part of the Reef Restoration and Adaptation Program, funded by a partnership between the Australian government’s Reef Trust and the Great Barrier Reef Foundation. ■

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  • Cold War-era research station Camp Century samples are revealing new insights about climate change today.

    Cold War-era research station Camp Century samples are revealing new insights about climate change today.

    It sounds like something out of science fiction: In the late 1950s, the US Army carved a tiny “city” into the Greenland ice sheet, 800 miles from the North Pole. It had living facilities, and scientific labs, and working showers, all powered by one small nuclear reactor.

    The research base was called “Camp Century,” a Cold War scientific project that helped researchers deepen their understanding of ice. As part of their efforts, they wound up drilling close to a mile down through the ice sheet to pull up an ice core: a series of long cylinders of ice that serve as a record of Earth’s history, with everything from atmospheric gases to volcanic fallout preserved in their tightly packed layers.

    The ice from Camp Century has been thoroughly sampled and studied since it first came out of the ice sheet. It, along with the ice from many other ice cores, has taught us a lot about Earth’s climate going back tens of thousands of years — about how abruptly climate can change and the role that greenhouse gases play in warming.

    But the drillers at Camp Century brought up more than just ice. They also brought up several feet of sediment from beneath it. Except, as a geoscientist named Paul Bierman, who wrote a whole book about the ice and sediment from Camp Century, explains, these samples went largely understudied for decades, with just a handful of papers written about them.

    “ I think the focus of the community was almost laser on the ice and not on the stuff beneath it,” he says.

    These sediments from underneath the ice were so undervalued, in fact, that they disappeared into some freezers in Denmark for years. Until, in 2017, some researchers found them again. And when scientists finally started to study these sediments in earnest, they discovered a bonanza of former lifeforms and a trove of information.

    On the most recent episode of Vox’s Unexplainable podcast, we explore these long-ignored sediments, and learn what they can teach us about our climate past — and future.

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  • Widespread temporal niche partitioning in an adaptive radiation of cichlid fishes

    Widespread temporal niche partitioning in an adaptive radiation of cichlid fishes

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  • SpaceX’s Starship releases first batch of mock satellites in orbit: What is Starlink’s deployment system and how does it work |

    SpaceX’s Starship releases first batch of mock satellites in orbit: What is Starlink’s deployment system and how does it work |

    SpaceX’s Starship achieved a key milestone in its tenth test flight by deploying its first batch of mock Starlink satellites into orbit. The demonstration, reported by Reuters, marks a turning point after several failed test attempts and showcases the rocket’s unique “Pez”-like dispenser system designed for mass satellite deployment. While the satellites were dummies, the success highlights the future potential of Starship as the backbone of Elon Musk’s ambitious satellite internet project, Starlink. Alongside this, the mission also tested new heat shield tiles during reentry, bringing the spacecraft closer to operational readiness.

    How the Starlink’s Pez-like dispenser works

    The Starship’s satellite deployment system has earned the nickname “Pez dispenser” due to its resemblance to the classic candy dispenser. Instead of side-mounted ejections, the system releases satellites vertically from an internal bay. During the test, eight dummy satellites were pushed into orbit, proving the mechanism’s capability. This design allows SpaceX to carry and release larger batches of satellites at once, increasing efficiency and reducing costs compared to the Falcon 9 system currently used for Starlink launches.

    Why mock satellites matter in testing

    The use of non-functional satellites in this mission allowed SpaceX to evaluate the reliability of Starship’s dispenser without risking expensive hardware. These mock payloads replicate the weight and dimensions of real Starlink satellites, giving engineers accurate data on deployment dynamics, orbital placement, and potential risks. By validating the process with test hardware, SpaceX reduces the chance of costly setbacks when real Starlink payloads are launched aboard Starship in the future.

    Starship’s role in Starlink’s future

    Starlink, SpaceX’s satellite internet venture, currently relies on the Falcon 9 rocket for launches. However, Starship’s larger payload capacity will enable the deployment of dozens, potentially hundreds, of satellites in a single mission. This efficiency is crucial to rapidly building out Starlink’s global constellation, which already numbers over 6,000 satellites. If successful, Starship could dramatically cut costs, accelerate expansion, and allow larger next-generation satellites with enhanced capabilities to reach orbit.

    What comes next for Starship

    While the dispenser test was a success, many technical hurdles remain before Starship can operate routinely. Heat shield durability, orbital refueling, and safe landings are still under development. NASA is watching closely, as Starship is slated to deliver astronauts to the Moon under Artemis III, currently scheduled for 2027. For now, the mock satellite deployment offers SpaceX proof that its innovative payload system works—and a glimpse into the future of how thousands of Starlink satellites could soon be launched into space more efficiently.


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  • “Breakthrough” 3D printed scaffolds help repair spinal cord injuries in rats

    “Breakthrough” 3D printed scaffolds help repair spinal cord injuries in rats

    Your seat at the Additive Manufacturing Advantage awaits! Register free for AMA: Energy and AMA: Automotive & Mobility.

    Researchers at the University of Minnesota (UMN) have designed a new approach to repairing damaged spinal cords. 

    Published in Advanced Healthcare Materials, the researchers combined 3D printed scaffolds with spinal neural progenitor cells (sNPCs) that assembled into organoid-like structures and were able to improve partial movement in rats with complete spinal cord injuries. Although still in early stages, the findings offer a glimpse of how engineered tissue structures might eventually help patients who currently have no way to regain lost nerve function. 

    Spinal cord injury affects more than 300,000 people in the US, often leading to permanent paralysis. While medical care has improved survival and quality of life, treatments that restore lost connections remain out of reach. 

    Previous studies have shown that sNPCs, can form new links with host tissue when transplanted. But injected cells on their own tend to scatter and lack the structure needed to form organized networks. Led by Ann M. Parr, MD, PhD, Professor of Neurosurgery, the Minnesota team set out to solve this by giving the cells a framework that could guide their growth.

    Custom 3D printed silicone scaffold. Photo via McAlpine Research Group / UMN.

    Guiding neurons with silicone scaffolds

    For this project, the researchers turned to a custom-built 3D printer equipped with multiple extrusion heads to create scaffolds made of silicone. Each scaffold contained tiny channels designed to imitate the architecture of the spinal cord. 

    Human induced pluripotent stem cells were first converted into sNPCs, then printed into these channels with a supportive gel. The channels directed the growth of axons and dendrites along defined paths, encouraging the cells to assemble into structures resembling natural spinal cord tissue. In this way, the scaffold provided both support and instruction, shaping how the cells matured.

    In the lab, the scaffolds proved capable of sustaining cells for over a year. Within weeks, the sNPCs differentiated into several types of neurons normally found in the spinal cord, including those essential for motor control. Imaging revealed axons filling the scaffold channels and spreading across the surface to form interconnected networks. 

    Gene analysis showed that the 3D environment produced a broader range of spinal specific neurons than flat cultures, and electrical testing confirmed that the neurons were not only surviving but functioning, firing signals in ways consistent with mature cells.

    Encouraged by these results, the team tested the scaffolds in rats with severed spinal cords. Two organoid scaffolds were placed into the gap left by the injury. 

    Over twelve weeks, the treated animals gradually regained some movement in their hind limbs, while those given empty scaffolds or no scaffold showed little progress. Electrical recordings reinforced the behavioral results, showing that signals from the brain were able to cross the injury site and activate muscles more effectively in the treated rats.

    Detailed examination after the study ended provided further insight. A majority of the implanted cells (~63%) matured into neurons, while a portion became oligodendrocytes, and the neurons integrated with the host spinal cord. These neurons projected axons both above and below the injury, forming synapses with existing cells.

    In several cases, they developed organized bundles of fibers suggesting the potential for relay-like systems across the damaged area, rather than full relay restoration. The researchers emphasize that the work is still at an early stage, noting that the current tests were limited to animals and relied on silicone scaffolds that cannot remain in the body permanently.

    Future studies will focus on biodegradable materials that dissolve as natural tissue forms. They also plan to add other cell types, including dorsal neurons, to restore sensory as well as motor function, and to refine scaffold designs to better mimic the spinal cord’s layered structure.

    AM research in spinal repair

    The precision of 3D printing allows scientists to design scaffolds that guide nerve growth, offering a structured path to recovery after spinal trauma.

    Recently, researchers at Royal College of Surgeons in Ireland (RCSI) University of Medicine and Health Sciences and Trinity College Dublin created a 3D printed spinal implant that blends a soft, tissue-like matrix with conductive fibers designed to deliver electrical stimulation across damaged nerves. 

    Produced through melt electrowriting, the implant uses polycaprolactone fibers coated with MXene nanosheets, arranged in low-, medium-, and high-density networks to fine-tune conductivity. In lab tests, neurons grew more robustly on MXene-coated fibers, while astrocytes were less reactive and microglia showed no inflammation. Medium-density scaffolds offered the best balance, supporting longer axon growth and more mature neurons under electrical stimulation, pointing to a promising avenue for spinal repair.

    Elsewhere, scientists at the University of California San Diego’s School of Medicine and Institute of Engineering in Medicine (IEM) designed a rapid 3D printed spinal cord implant that helped restore movement in rats with serious injuries. The tiny 2 mm scaffolds were printed in just 1.6 seconds, with 200 µm channels that directed stem cell growth and encouraged axons to reconnect across damaged tissue. 

    Once implanted, the structures supported blood vessel growth and led to notable recovery of hind limb function. To test clinical feasibility, the researchers also printed larger, four-centimeter implants based on MRI data in under 10 minutes, marking an important step toward human applications.

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    Featured image shows custom 3D printed silicone scaffold. Photo via McAlpine Research Group / UMN.

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  • Saturn is at its best in September 2025. Here’s how to see it, and catch its meeting with the Moon

    Saturn is at its best in September 2025. Here’s how to see it, and catch its meeting with the Moon

    Saturn reaches opposition on 21 September 2025, rising to a peak altitude of 34° as seen from the centre of the UK.

    The planet is within Pisces, shining away with a slightly off-white hue at mag. +0.2 during opposition.

    Credit: Pete Lawrence

    On 8 September, it can be seen close to a 98%-lit waning gibbous Moon shortly after both objects rise and the sky darkens, at around 21:00 BST (20:00 UT).

    Chart showing the location of Saturn in the night sky during September 2025, including at opposition on 21 September. Credit: Pete Lawrence
    Chart showing the location of Saturn in the night sky during September 2025, including at opposition on 21 September. Credit: Pete Lawrence

    Seeing Saturn’s rings

    If you had a chance to catch a view of Saturn through a telescope in August month, you would have seen the rings were narrow but obvious.

    At the start of August, the planet’s southern pole was tilted towards Earth by 3.4°, so they appeared like a thin elliptical band around the centre of the globe.

    However, by 1 September, the tilt angle will have reduced to 2.5° and the rings will be noticeably harder to see again.

    Saturn ring plane crossing 23 March 2025
    Credit: NASA/JPL

    Saturn underwent a ring plane crossing back in March 2025, but at the time it was poorly placed for observation.

    The next isn’t due until 2038, but between 11 November and 8 December this year, Saturn will appear to wobble to a very narrow tilt angle of just 0.4°.

    Although not a true ring plane crossing, that is narrow enough to resemble a crossing through smaller scopes.

    Observing highlights in September

    Saturn and Neptune are visited by a 98%-lit waning Moon on 8 September 2025. Credit: Pete Lawrence
    Saturn and Neptune are visited by a 98%-lit waning Moon on 8 September 2025. Credit: Pete Lawrence

    On 21 September, when Saturn reaches opposition, the tilt angle will be 1.8°. Such a narrow tilt continues to offer opportunities to see Titan and its shadow cross the planet’s globe.

    At the end of September, Saturn remains at mag. +0.2 and, thanks to a slow westward drift, will have wandered across the border of Pisces back into neighbouring Aquarius.

    Currently, Saturn and Neptune remain close to one another in the sky, lying 2.6° apart on opposition night, with Neptune located northeast of Saturn.

    Titan transit of Saturn Eric Sussenbach, Willemstad, Curaçao, 1 August 2024 Equipment: Player One Neptune 664C camera, Celestron EdgeHD 14-inch Schmidt-Cassegrain, iOptron CEM120 mount
    Titan transit of Saturn Eric Sussenbach, Willemstad, Curaçao, 1 August 2024 Equipment: Player One Neptune 664C camera, Celestron EdgeHD 14-inch Schmidt-Cassegrain, iOptron CEM120 mount

    Saturn, September 2025 quick facts

    • Best time to see: 21 September, 01:00 BST (00:00 UT)
    • Altitude: 35° 
    • Location: Pisces
    • Direction: South
    • Features: Rings, subtle atmospheric features, moons
    • Recommended equipment: 150mm or larger

    Share your Saturn observations and images with us by emailing contactus@skyatnightmagazine.com.

    This guide appeared in the September 2025 issue of BBC Sky at Night Magazine

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  • How did life get multicellular? Five simple organisms could have the answer

    How did life get multicellular? Five simple organisms could have the answer

    For some three billion years, unicellular organisms ruled Earth. Then, around one billion years ago, a new chapter of life began. Early attempts at team living began to stick, paving the way for the evolution of complex organisms, including animals, plants and fungi.

    Across all known life, the move to multicellularity happened at least 40 times, suggests one study1. But, in animals, it seems to have occurred only once.

    Beginning in the early 2000s, researchers interested in this remarkable event made a series of unexpected discoveries. The prevailing view held that a flood of genes had to evolve to enable the key properties of multicellularity2: the ability of cells to stick together, communication using molecular signals and the coordinated regulation of gene expression that causes each cell to specialize and take its position in the organism. But studies found that some unicellular organisms express a slew of proteins that control key properties of multicellularity in animals3,4. The molecular toolkit required for multicellularity seems to have existed well before the first animals came to be.

    “This work has rewritten our understanding of animal origins,” says William Ratcliff, an evolutionary biologist at the Georgia Institute of Technology in Atlanta. “And it makes us ask different questions.”

    The two teams behind much of this research were led by evolutionary biologist and geneticist Nicole King at the University of California, Berkeley, and by evolutionary biologist Iñaki Ruiz-Trillo at the Institute of Evolutionary Biology in Barcelona, Spain. They have since expanded into a small community of scientists that has developed more than a dozen of these species into model organisms. All of these species are eukaryotes, which are distinct from prokaryotes in that they have a nucleus, and belong to lineages closely related to animals: choanoflagellates, filastereans, ichthyosporeans and corallochytreans (see ‘Animals’ unicellular relatives’). Many of the model species dabble in multicellularity by occasionally forming colonies.

    Source: Ruiz-Trillo, I. et al. Annu. Rev. Microbiol. 77, 499–516 (2023).

    Part of what makes these organisms so interesting is how different they are — in appearance, life stages and genetic make-up — researchers say. Each of the organisms, five of which are featured here, offers a peek into the evolutionary paths that could have led to animals. Looking across several lineages to piece together this event has become “the philosophy of this scientific community”, says molecular biologist Elena Casacuberta, who jointly runs the laboratory in Barcelona with Ruiz-Trillo. “Only with a comparative approach can we attempt to have a more accurate picture.”

    The top model

    Scanning electron micrograph of cells that have clustered together to look like a flower

    When the single-celled choanoflagellate Salpingoeca rosetta divides in the presence of bacteria, its daughter cells form a rosette pattern.Credit: Mark Dayel

    Salpingoeca rosetta was among the organisms that King investigated in her early work on multicellularity. It belongs to the choanoflagellates, which are the closest living relatives of animals. This group diverged from a common ancestor with animals more than 600 million years ago.

    Like other choanoflagellates, S. rosetta has a spherical cell body that sports a collar of thin membrane protrusions called microvilli, which are used to capture bacteria swept up for dinner by a long tail (known as a flagellum). It was isolated in 2000 from mudflats off the coast of Virginia; researchers haven’t managed to find it again in the wild. Under certain environmental conditions, S. rosetta cells divide clonally, producing genetically identical daughter cells that form colonies by circling up in a rosette pattern, with flagella undulating outward. But when King first started working with the organism in the lab, she could not budge it from its unicellular form. A chance experiment revealed that secretions by a specific prey bacterium act as a signal for the cells to start dividing.

    A ‘lost world’ of early microbes thrived one billion years ago

    In addition to forming rosettes, the organism has at least one other multicellular conformation and a few distinct free-living cell types. When confined to a tight space, for example, S. rosetta cells withdraw their flagella and become amoeboid, lacking a firm shape and extending slender tentacles called filopodia to pull themselves along.

    “It has such an amazing diversity in response to a myriad of environmental cues,” says David Booth, a biochemist at the University of California, San Francisco.

    In 2003, King and her colleagues reported the presence of proteins involved in cell adhesion and cell signalling in choanoflagellate species3. They later identified a more in-depth toolkit for multicellularity when they sequenced the genome of S. rosetta5.

    Salpingoeca rosetta is the Drosophila of choanoflagellates — the most widely studied species and the one for which researchers have developed the most extensive tools for directly altering the genome. In 2018, during a postdoc in King’s lab, Booth and his colleagues managed to add DNA encoding fluorescent proteins into S. rosetta6 and, in 2020, found ways to edit its genome using CRISPR7. Such methods have made it possible to tinker directly with genes that researchers say could be key to multicellularity — and to study the proteins that those genes express.

    With the tools’ help, microbiologist Arielle Woznica at the University of Texas at Austin, a former graduate student in King’s lab, is exploring how choanoflagellates respond to bacterial attackers. Biochemist Florentine Rutaganira, a former postdoc in King’s lab now at Stanford University in California, is investigating enzymes called tyrosine kinases — linchpins of cell signalling in animals that are present in similar numbers in S. rosetta.

    Master aggregator

    Colour micrograph of many black circular cells on a yellow background

    Environmental cues can trigger aggregation in Capsaspora owczarzaki.Credit: H. Suga et al./Nature Commun.

    Capsaspora owczarzaki is a member of the filasterean lineage, which diverged from a common ancestor with animals perhaps a couple of hundred million years earlier than did choanoflagellates.

    Ruiz-Trillo first became interested in the organism as a postdoc, just as King’s lab was setting up to study S. rosetta. He and his colleagues found that C. owczarzaki, too, seemed to be closely related to animals4. Ruiz-Trillo set out to study lineages other than choanoflagellates, because investigating several lineages could provide a fuller picture of the shared ancestor with animals. After sequencing the genome of C. owczarzaki, Ruiz-Trillo and his team reported in 2013 that it has many genes related to multicellularity, including some that choanoflagellates lack — such as those that encode cell-surface proteins called integrins, which help cells to stick to each other and to their environment8.

    These bizarre ancient species are rewriting animal evolution

    Discovered in 2002 inside a freshwater snail, C. owczarzaki spends most of its life cycle as a unicellular amoeba, but environmental cues can push the cells into a multicellular phase in which clusters swarm together and fuse into increasingly large aggregates. This path to multicellularity is different from the clustering through clonal division observed in choanoflagellates. Ruiz-Trillo says that clonal division is “the standard way in which people were thinking animals evolve”.

    During development in animals, a single cell divides into many cells with identical genomes, a process that probably avoids any genetic conflict arising between cells. It’s therefore an easy leap to assume that clonal division was also the evolutionary path to the first animals, Ruiz-Trillo says. But aggregation exists in many eukaryotic lineages as a fast and easy way for cells to form 3D structures, and he thinks this mechanism deserves a closer look.

    Ruiz-Trillo and his colleagues found that C. owczarzaki uses some key genes related to multicellularity during this aggregated phase9. Perhaps aggregation was the essential step in the evolution of animals, Ruiz-Trillo says, or perhaps it was just one part of the process.

    Capsaspora owczarzaki is one of a handful of unicellular species that Casacuberta and Ruiz-Trillo happily send to other labs on request.

    The dualist

    A microscope video of two circular clusters of cells that move into frame then appear to turn inside out and back again

    In water from a tide pool, a colony of Choanoeca flexa cells that has taken on a cupped shape reverses its curvature. Another colony joins it, and their curvatures reverse again.Credit: Benjamin T. Larson

    The serendipitous discovery in 2017 of another species of choanoflagellate, Choanoeca flexa, demonstrated how much variation exists in this group alone. Thibaut Brunet, an evolutionary cell biologist now at the Pasteur Institute in Paris, found C. flexa in Curaçao, with his colleagues while attending a workshop as postdoc in King’s lab. After collecting water samples from shallow marine tide pools while touring the island, he and his colleagues gaped at the scene under the microscope.

    Individual cells, which look much like S. rosetta cells, form a cupped monolayer sheet, with all the flagella pointing in the same direction10. In response to light or darkness, “they could reverse their curvature in a few seconds, flipping inside out like a child’s toy or an umbrella”, says Brunet. “We were screaming and jumping up and down when we saw it — we were probably ridiculous.”

    The secret lives of cells — as never seen before

    Although researchers are still developing methods to manipulate its genome, C. flexa has at least one big benefit as a model organism. Other organisms have been studied only in the lab after they were discovered, says evolutionary biologist Núria Ros-Rocher, a postdoc in Brunet’s lab. Researchers don’t know how or where to find them again. But C. flexa has been retrieved repeatedly from the tide pools in which it was first found. “We were very lucky, because we could go back to the natural environment to understand how it’s linked to the organism’s multicellular behaviour,” says Ros-Rocher.

    Those pools face whiplash changes — water often heats up and evaporates within days, leaving the organism afloat in sharply elevated salinity or beached on dried mud before the tide submerges it again. Brunet and his team found that C. flexa, like S. rosetta, can go from a unicellular to multicellular state by clonal division. But it can use aggregation, too, and sometimes combines both strategies at once.

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  • X-ray, Radio Go ‘Hand in Hand’ in New NASA Image

    X-ray, Radio Go ‘Hand in Hand’ in New NASA Image

    A pulsar known as the “Hand of God” reveals strange filaments, patchy remnants, and puzzling signals, leaving scientists searching for answers. Credit: X-ray: NASA/CXC/Univ. of Hong Kong/S. Zhang et al.; Radio: ATNF/CSIRO/ATCA; H-alpha: UK STFC/Royal Observatory Edinburgh; Image Processing: NASA/CXC/SAO/N. Wolk
    • A stunning new composite image captures the hand-shaped nebula MSH 15-52 along with the remains of the supernova that formed it.
    • Astronomers combined X-ray data from NASA’s Chandra Observatory with radio observations from the Australia Telescope Compact Array, uncovering fresh details and hidden structures.
    • At the center lies a pulsar, an ultra-dense neutron star spinning rapidly, which fuels the creation of the nebula.
    • This extraordinary system began when a massive star used up its nuclear fuel, collapsed inward, and then exploded in a brilliant supernova.

    A Cosmic Hand in Space

    In 2009, NASA’s Chandra X-ray Observatory unveiled a striking image of a pulsar surrounded by a nebula shaped like a giant hand.

    Since that first release, astronomers have continued to track the object using Chandra along with other powerful telescopes. Most recently, scientists paired new radio observations from the Australia Telescope Compact Array (ATCA) with Chandra’s X-ray data, creating a more detailed portrait of the aftermath of this stellar explosion and offering new clues about its unusual appearance.

    Fresh Insights from Radio and X-Ray Data

    At the heart of this dramatic view is pulsar B1509-58, a rapidly rotating neutron star that measures only about 12 miles across. Despite its small size, it produces a sprawling nebula (known as MSH 15-52) that stretches more than 150 light-years, or roughly 900 trillion miles. This vast cloud of energetic particles takes on the eerie shape of a human hand, with a glowing palm and outstretched fingers reaching upward to the right in X-ray light.

    The pulsar itself was born when a massive star collapsed after exhausting its supply of nuclear fuel. The inward crash triggered a supernova, blasting the star’s outer layers into space and leaving behind the dense remnant.

    Today, B1509-58 rotates nearly seven times per second and carries a magnetic field estimated to be about 15 trillion times stronger than Earth’s. This extraordinary combination of speed and magnetism makes it one of the galaxy’s most powerful natural dynamos, driving a fierce outflow of electrons and other particles that form the nebula.

    Hand in Hand NASA Image Annotated
    Near the center of these images lies the pulsar B1509-58, a rapidly spinning neutron star that is only about 12 miles in diameter. This tiny object is responsible for producing an intricate nebula (called MSH 15-52) that spans over 150 light-years, or about 900 trillion miles. The nebula, which is produced by energetic particles, resembles a human hand with a palm and extended fingers pointing to the upper right in Chandra’s X-ray view. Radio data from ATCA provides new information about this exploded star and its environment. This image also contains optical data of hydrogen gas. The bright red and gold areas near the top of the image show the remains of the supernova that formed the pulsar. Credit: X-ray: NASA/CXC/Univ. of Hong Kong/S. Zhang et al.; Radio: ATNF/CSIRO/ATCA; H-alpha: UK STFC/Royal Observatory Edinburgh; Image Processing: NASA/CXC/SAO/N. Wolk

    One of the Galaxy’s Most Powerful Generators

    In this new composite image, the ATCA radio data (represented in red) has been combined with X-rays from Chandra (shown in blue, orange and yellow), along with an optical image of hydrogen gas (gold). The areas of overlap between the X-ray and radio data in MSH 15-52 show as purple. The optical image shows stars in the field of view along with parts of the supernova’s debris, the supernova remnant RCW 89. A labeled version of the figure shows the main features of the image.

    Radio data from ATCA now reveals complex filaments that are aligned with the directions of the nebula’s magnetic field, shown by the short, straight, white lines in a supplementary image. These filaments could result from the collision of the pulsar’s particle wind with the supernova’s debris.

    Hand in Hand NASA Image Vectors
    Complex filaments aligned with the directions of the nebula’s magnetic field. Credit: X-ray: NASA/CXC/Univ. of Hong Kong/S. Zhang et al.; Radio: ATNF/CSIRO/ATCA; H-alpha: UK STFC/Royal Observatory Edinburgh; Image Processing: NASA/CXC/SAO/N. Wolk

    Mysterious Filaments and Magnetic Fields

    By comparing the radio and X-ray data, researchers identified key differences between the sources of the two types of light. In particular, some prominent X-ray features, including the jet towards the bottom of the image and the inner parts of the three “fingers” towards the top, are not detected in radio waves. This suggests that highly energetic particles are leaking out from a shock wave — similar to a supersonic plane’s sonic boom — near the pulsar and moving along magnetic field lines to create the fingers.

    The radio data also shows that RCW 89’s structure is different from typical young supernova remnants. Much of the radio emission is patchy and closely matches clumps of X-ray and optical emission. It also extends well beyond the X-ray emission. All of these characteristics support the idea that RCW 89 is colliding with a dense cloud of nearby hydrogen gas.

    However, the researchers do not fully understand all that the data is showing them. One area that is perplexing is the sharp boundary of X-ray emission in the upper right of the image that seems to be the blast wave from the supernova — see the labeled feature. Supernova blast waves are usually bright in radio waves for young supernova remnants like RCW 89, so it is surprising to researchers that there is no radio signal at the X-ray boundary.

    Perplexing Boundaries and Missing Signals

    MSH 15–52 and RCW 89 show many unique features not found in other young sources. There are, however, still many open questions regarding the formation and evolution of these structures. Further work is needed to provide better understanding of the complex interplay between the pulsar wind and the supernova debris.

    A paper describing this work, led by Shumeng Zhang of the University of Hong Kong, with co-authors Stephen C.Y. Ng of the University of Hong Kong and Niccolo’ Bucciantini of the Italian National Institute for Astrophysics, has been published in The Astrophysical Journal.

    Reference: “High-resolution Radio Study of Pulsar Wind Nebula MSH 15–52 and Supernova Remnant RCW 89” by S. Zhang, C.-Y. Ng and N. Bucciantini, 20 August 2025, The Astrophysical Journal.
    DOI: 10.3847/1538-4357/adf333

    NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

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  • Gut microbiota–derived metabolite drives atherosclerosis

    • RESEARCH HIGHLIGHT

    Strategies to identify and treat early atherosclerosis are urgently needed to reduce the risk of cardiovascular complications. A paper in Nature now reports that imidazole propionate (ImP), a molecule made by bacteria residing in the gut, contributes to atherosclerosis development in mice and is linked to early active atherosclerosis in humans. In mice, pharmacological blockade of the imidazoline-1 receptor (I1R), which is expressed in several cell types including myeloid cells, inhibited ImP- or high-cholesterol-induced atherosclerosis development.

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    doi: https://doi.org/10.1038/d41573-025-00141-8


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  • Shark Teeth Are Vulnerable to Rising Ocean Acidification

    Shark Teeth Are Vulnerable to Rising Ocean Acidification


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    A leading cause of a rising pH value in the world’s oceans is human CO2 emission. As more CO2 is released into the atmosphere and absorbed by the oceans, the water becomes more acidic. This poses problems for many organisms – including sharks, a new study showed. Scientists incubated shark teeth in water with pH levels that reflect the current ocean pH, and in water with a pH value that oceans are predicted to reach by 2300. In the more acidic water of the simulated scenario, shark teeth, including roots and crowns, were significantly more damaged. This shows how global changes reach all the way to the microstructure of sharks’ teeth, the researchers said.

    Sharks can famously replace their teeth, with new ones always growing as they’re using up the current set. As sharks rely on their teeth to catch prey, this is vital to the survival of one of the oceans’ top predators.

    But the ability to regrow teeth might not be enough to ensure they can withstand the pressures of a warming world where oceans are getting more acidic, new research has found. Researchers in Germany examined sharks’ teeth under different ocean acidification scenarios and showed that more acidic oceans lead to more brittle and weaker teeth.

    “Shark teeth, despite being composed of highly mineralized phosphates, are still vulnerable to corrosion under future ocean acidification scenarios,” said first author of the Frontiers in Marine Science article, Maximilian Baum, a biologist at Heinrich Heine University Düsseldorf (HHU). “They are high developed weapons built for cutting flesh, not resisting ocean acid. Our results show just how vulnerable even nature’s sharpest weapons can be.”

    Damage from root to crown

    Ocean acidification is a process during which the ocean’s pH value keeps decreasing, resulting in more acidic water. It is mostly driven by the release of human-generated CO2. Currently, the average pH of the world’s oceans is 8.1. In 2300, it is expected to drop to 7.3, making it almost 10 times more acidic than it currently is.

    For their study, the researchers used these two pH values to examine the effects of more and less acidic water on the teeth of Blacktip reef sharks. Divers collected more than 600 discarded teeth from an aquarium housing the sharks. 16 teeth – those that were completely intact and undamaged – were used for the pH experiment, while 36 more teeth were used to measure before and after circumference. The teeth were incubated for eight weeks in separate 20-liter tanks. “This study began as a bachelor’s project and grew into a peer-reviewed publication. It’s a great example of the potential of student research,” said the study’s senior author, Prof Sebastian Fraune, who heads the Zoology and Organismic Interactions Institute at HHU. “Curiosity and initiative can spark real scientific discovery.”

    Compared to the teeth incubated at 8.1 pH, the teeth exposed to more acidic water were significantly more damaged. “We observed visible surface damage such as cracks and holes, increased root corrosion, and structural degradation,” said Fraune. Tooth circumference was also greater at higher pH levels. Teeth, however, did not actually grow, but the surface structure became more irregular, resulting in it appearing larger on 2D images. While an altered tooth surface may improve cutting efficiency, it potentially also makes teeth structurally weaker and more prone to break.

    Small damage, big effects

    The study only looked at discarded teeth of non-living mineralized tissue, which means repair processes that may happen in living organisms could not be considered. “In living sharks, the situation may be more complex. They could potentially remineralize or replace damaged teeth faster, but the energy costs of this would be probably higher in acidified waters,” Fraune explained.

    Blacktip reef sharks must swim with their mouths permanently open to be able to breathe, so teeth are constantly exposed to water. If the water is too acidic, the teeth automatically take damage, especially if acidification intensifies, the researchers said. “Even moderate drops in pH could affect more sensitive species with slow tooth replication circles or have cumulative impacts over time,” Baum pointed out. “Maintaining ocean pH near the current average of 8.1 could be critical for the physical integrity of predators’ tools.”

    In addition, the study only focused on the chemical effects of ocean acidification on non-living tissue. Future studies should examine changes to teeth, their chemical structure, and mechanical resilience in live sharks, the researchers said. The study shows, however, that microscopic damage might be enough to pose a serious problem for animals depending on their teeth for survival. “It’s a reminder that climate change impacts cascade through entire food webs and ecosystems,” Baum concluded.


    Reference:     Maximilian Baum M, Haussecker T, Walenciak O, et al. Simulated ocean acidification affects shark tooth morphology. Front Mar Sci. 2025. doi: 10.3389/fmars.2025.1597592


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