Category: 7. Science

  • Scientists open new atlas of genetic diversity with advanced sequencing

    Scientists open new atlas of genetic diversity with advanced sequencing

    A landmark study harnesses long-read sequencing to reveal vast, previously undetected structural variations in human DNA, reshaping our understanding of genetics and disease potential.

    Study: Structural variation in 1,019 diverse humans based on long-read sequencing

    In a recent study published in the journal Nature, researchers investigated large-scale structural variants (SVs), complex and poorly understood insertions, deletions, and rearrangements in DNA, using next-generation ‘long-read’ sequencing. Their groundbreaking dataset comprised 1,019 individuals across 26 global populations. The study further leveraged a novel graph-based analytical framework, allowing for the creation of over 107,000 sequence-resolved biallelic SVs, which the authors made open-access.

    The high-resolution genomic investigation not only significantly furthers our understanding of the true diversity of human genetics but also progresses our identification and future management of disease-causing genetic variants in patients.

    Background

    Biology textbooks often depict the human genome as a linear string of three billion combinations of A, T, G, and C – our DNA, the building blocks of our lives. The reality, however, is far more dynamic, with our DNA demonstrating large-scale structural variants (SVs)—deletions, duplications, insertions, and inversions of entire DNA segments.

    Despite accounting for most base-pair (bp) differences between any two organisms and being major contributors to and modulators of human health, they remain notoriously difficult to study and poorly understood. Short-read sequencing, the predominant sequencing technology of today, splices long DNA segments into tiny fragments, which are then amplified. While effective for small variants, these technologies struggle to map complex SVs, especially large insertions and multiallelic variable number tandem repeats (VNTRs), which are sometimes missed entirely.

    Consequently, a vast majority of the human genome remains invisible to science and medicine, allowing potentially curable genetic diseases to persist unabated. Long-read sequencing is a relatively novel technology that can read much longer, continuous stretches of DNA, thereby overcoming short-read sequencing’s primary SV-associated shortcoming. Harnessing this technology could unlock this hidden portion of the human genome and the medical treasures that lie within.

    About the study

    The present work does just this: A consortium of researchers undertook a massive, multinational project to map SVs using a globally diverse cohort. Study samples were acquired from the 1000 Genomes Project (1kGP) and initially comprised 1,064 samples (lymphoblastoid cell lines).

    Strict quality control (QC) using a combination of DNA concentration determination (multimode microplate reader), DNA purity evaluation (spectrophotometer), and DNA fragment length verification (Femto Pulse system) reduced the dataset to 1,019. This dataset comprised participants from 26 distinct ancestries across Africa, the Americas, Europe, and East and South Asia.

    a, Breakdown of self-identified geographical ancestries for 1,019 long-read genomes representing 26 geographies (that is, populations) from 5 continental regions. The three-letter codes used are equivalent to those used in the 1kGP phase III18 and are resolved in Supplementary Table 2. b, ONT sequence coverage per sample, expressed as fold-coverage (left), and N50 read length in base pairs (right). c, Schematic of the SAGA framework for graph-aware discovery and genotyping of SVs using a pangenome graph augmentation approach. Basemap in a from Natural Earth data (https://www.naturalearthdata.com).a, Breakdown of self-identified geographical ancestries for 1,019 long-read genomes representing 26 geographies (that is, populations) from 5 continental regions. The three-letter codes used are equivalent to those used in the 1kGP phase III18 and are resolved in Supplementary Table 2. b, ONT sequence coverage per sample, expressed as fold-coverage (left), and N50 read length in base pairs (right). c, Schematic of the SAGA framework for graph-aware discovery and genotyping of SVs using a pangenome graph augmentation approach. Basemap in a from Natural Earth data (https://www.naturalearthdata.com).

    The long-read sequencing platform used was the Oxford Nanopore Technologies (ONT) LRS, a cutting-edge technology capable of generating data with a median read length of over 20,000 base pairs.

    To analyze this complex dataset, they engineered a novel computational framework called SAGA (SV analysis by graph augmentation). This process involved four key steps: First, aligning long reads to both linear (GRCh38) and graph-based (HPRC) references; second, SV discovery using Sniffles, DELLY, and the graph-aware SVarp algorithm, including specialized remapping to resolve inversion alignment artifacts; third, augmenting the pangenome graph to incorporate new SVs despite complexities in multiallelic VNTR genotyping; and finally, genotyping the cohort using Giggles software to determine variant carriers (n = 967 samples), noting that multiallelic sites showed higher Mendelian inconsistency (15.1%).

    Study findings

    The present study resulted in the production of a richly annotated, publicly available catalog of more than 100,000 sequence-resolved SVs (biallelic), alongside 369,685 multiallelic variable number tandem repeats (VNTRs) genotyped using the Vamos tool. Identified SVs included inversions, deletions, duplications, and insertions, totalling a greater than tenfold increase in the number of fully resolved insertion sites, filling a critical gap in human genomic knowledge.

    Mendelian consistency experiments leveraging family trios (two parents and a child) within the cohort demonstrated the study’s high accuracy and extremely low error rate (deletions and insertions at just 3.87% and 4.44%, respectively) for biallelic SVs. Notably, most of the novel SVs identified in this study were found to be extremely rare, with 59.3% having a minor allele frequency (MAF) of less than 1%. Individuals of African descent demonstrated the highest degree of SV diversity.

    Finally, the study provided novel insights into the biological mechanisms that create SVs, detailing how mobile DNA elements, such as L1 and SVA retrotransposons, drive genetic innovation by promoting SV formation and translocation through locus-specific processes, including promoter hijacking (e.g., the 8q21.11 L1 source element).

    Conclusions

    The present study represents a commendable leap forward in our knowledge and understanding of human genomics. The application of long-read sequencing successfully allowed for the discovery and annotation of more SVs (especially insertions), and the diversity of the sample cohort (26 distinct ancestries across several continents) validates the generalizability and global application of study findings.

    Furthermore, the resultant comprehensive and accurate SV atlas, being open access, opens the doors to a new era of genetic medicine, allowing for the identification and early treatment of genetic conditions that we hitherto didn’t even know existed. Notably, when applied to rare-disease genomes, the resource filtered 55% of candidate SVs while retaining 94% (35/37) of validated causal variants. This open-access resource will be invaluable for the scientific community, enabling a deeper understanding of human evolution, population genetics, and the functional consequences of genetic variation.

    Journal reference:

    • Schloissnig, S., Pani, S., Ebler, J., Hain, C., Tsapalou, V., Söylev, A., Hüther, P., Ashraf, H., Prodanov, T., Asparuhova, M., Magalhães, H., Höps, W., Sotelo-Fonseca, J. E., Fitzgerald, T., Santana-Garcia, W., Moreira-Pinhal, R., Hunt, S., Pérez-Llanos, F. J., Wollenweber, T. E., … Korbel, J. O. (2025). Structural variation in 1,019 diverse humans based on long-read sequencing. Nature. DOI – 10.1038/s41586-025-09290-7, https://www.nature.com/articles/s41586-025-09290-7

    Continue Reading

  • Cambrian Nectocaridids are Early Descendants of Arrow Worms, New Fossil Shows

    Cambrian Nectocaridids are Early Descendants of Arrow Worms, New Fossil Shows

    Nectocaridids are enigmatic Paleozoic animals with a controversial position. These creatures were adapted for swimming, having fins, a head region with stalked camera eyes, and paired tentacles. Previous hypotheses have placed them in their own crustacean-like phylum, chordates, cephalopods, or radiodonts. An analysis of new fossils from North Greenland shows nectocaridids are actually early descendants of arrow worms, also known as chaetognaths. This discovery means the rather simple marine arrow worms had ancestors with much more complex anatomies and a predatory role higher up in the food chain.

    Life reconstruction of Nektognathus evasmithae. Image credit: Bob Nicholls.

    “Around 15 years ago a research paper, based on fossils from the famous Burgess Shale, claimed nectocaridids were cephalopods,” said University of Bristol paleontologist Jakob Vinther.

    “It never really made sense to me, as the hypothesis would upend everything we otherwise know about cephalopods and their anatomy didn’t closely match cephalopods when you looked carefully.”

    In new research, Dr. Vinther and colleagues described Nektognathus evasmithae, a new nectocaridid species from the 519-million-year-old Sirius Passet Lagerstätte of North Greenland.

    By analyzing 25 fossil specimens of Nektognathus evasmithae, they were able to pinpoint where nectocaridids fit into the tree of life.

    “We discovered our nectocaridids preserve parts of their nervous system as paired mineralized structures, and that was a giveaway as to where these animals sit in the tree of life,” Dr. Vinther said.

    Nektognathus evasmithae, holotype. Image credit: Vinther et al., doi: 10.1126/sciadv.adu6990.

    Nektognathus evasmithae, holotype. Image credit: Vinther et al., doi: 10.1126/sciadv.adu6990.

    Recently, the paleontologists uncovered fossils in Sirius Passet belonging to another branch of the animal tree — a small group of swimming worms called arrow worms or chaetognaths.

    “These fossils all preserve a unique feature, distinct for arrow worms, called the ventral ganglion,” said Dr. Tae-Yoon Park, a paleontologist at the Korean Polar Institute.

    The ventral ganglion is a large mass of nerves situated on the belly of living arrow worms, which is unique to this type of creature.

    The unique anatomy of the organ combined with the special preservation conditions means it sometimes is replaced by phosphate minerals during decay.

    “We now had a smoking gun to resolve the nectocaridid controversy,” Dr. Park said.

    “Nectocaridids share a number of features with some of the other fossils that also belong to the arrow worm stem lineage.”

    “Many of these features are superficially squid-like and reflect simple adaptations to an active swimming mode of life in invertebrates, just like whales and ancient marine reptiles end up looking like fish when they evolve such a mode of life.”

    “Nectocaridids have complex camera eyes just like ours,” Dr. Vinther said.

    “Living arrow worms can hardly form an image beyond working out roughly where the Sun shines.”

    “So, the ancestors of arrow worms were really complex predators, just like the squids that only evolved about 400 million years later.”

    “We can therefore show how arrow worms used to occupy a role much higher in the food chain.”

    “Our fossils can be much bigger than a typical living arrow worm and combined with their swimming apparatus, eyes and long antennae, they must have been formidable and stealthy predators.”

    “As further evidence for nectocaridids being swimming carnivores, we found several specimens with the carapaces of a swimming arthropod, called Isoxys, inside their digestive tract.”

    The study was published this week in the journal Science Advances.

    _____

    Jakob Vinther et al. 2025. A fossilized ventral ganglion reveals a chaetognath affinity for Cambrian nectocaridids. Science Advances 11 (30); doi: 10.1126/sciadv.adu6990

    Continue Reading

  • Seismologists tapped into the fiber optic cable network to study offshore faults

    Seismologists tapped into the fiber optic cable network to study offshore faults

    Environment  |  News releases  |  Research  |  Science

    July 24, 2025

    Continue Reading

  • The rise and fall of Paraceratherium: Earth’s largest-ever land mammal

    The rise and fall of Paraceratherium: Earth’s largest-ever land mammal

    Long before humans walked the planet, a massive creature ruled the forests and open plains of ancient Eurasia. Paraceratherium, a hornless giant and a distant relative of today’s rhinoceroses, lived during the Oligocene epoch, between 34 and 23 million years ago. With a shoulder height of nearly 16 feet and a body length over 24 feet, it is considered the largest land mammal ever to walk the Earth. Fossils suggest it may have weighed up to 24 tons, about three times heavier than the largest African elephants today.

    Despite its size, the story of this giant remained hidden for years. Scientists have pieced together its life from bones scattered across Asia and Eastern Europe. What emerged is not just a tale of a colossal herbivore but a vivid picture of mammalian evolution, resilience, and eventual extinction.

    A Journey Through Fossil Fragments

    The earliest clues came from the rocky landscapes of modern-day Pakistan. In the mid-1800s, British scientists collected bones in Balochistan, but it wasn’t until geologist Guy Ellcock Pilgrim returned in the early 1900s that more complete remains were uncovered. Pilgrim first called the species Aceratherium bugtiense, believing it was part of a known group of hornless rhinos.

    Estimated size of Paraceratherium (olive green) compared with that of humans, other large mammals, and the dinosaur Patagotitan. (CREDIT: Steveoc 86 – Own work, CC BY-SA 4.0)

    That changed in 1910, when British paleontologist Clive Forster-Cooper recognized that these bones belonged to a completely new kind of animal. He named it Paraceratherium, which means “near horn beast.” Over the next few decades, other scientists across Asia unearthed similar fossils. Each discovery brought new names—Baluchitherium, Indricotherium, and others—reflecting the isolated efforts of international researchers working without a shared framework.

    Russian expeditions near the Aral Sea in Kazakhstan found the most complete skeleton, though it lacked a skull. This specimen revealed important clues about the body shape and movement of the animal.

    Sorting Out the Scientific Confusion

    For much of the 20th century, paleontologists argued over how many species existed and what to call them. Some “splitters” named a new species for every minor difference in tooth size or skull shape. Others, called “lumpers,” believed these were all part of one broad group with natural variation.

    In 1989, paleontologists Spencer Lucas and Jay Sobus brought order to the chaos. They studied the fossils and concluded that most names referred to the same few species. They accepted four valid species within the Paraceratherium genus: P. bugtiense, P. transouralicum, P. prohorovi, and P. orgosensis.

    Later, Chinese paleontologist Tao Deng and colleagues suggested that six species existed, including newly described ones such as P. linxiaense and P. huangheense. Their work, based on more recent finds in China, highlighted the continued complexity of Paraceratherium’s evolutionary tree.

    From Small Ancestors to Giants

    Paraceratherium belonged to the Rhinocerotoidea superfamily, which includes today’s rhinos. Unlike its modern cousins, it came from a line called Indricotheriinae, which evolved from earlier, smaller animals like Forstercooperia and Juxia during the Eocene epoch.

    Over time, natural selection favored larger bodies and taller limbs. These changes helped the animals reach higher vegetation and travel long distances in search of food. The growing body size also offered protection against predators.

    Scientists once placed Paraceratherium in the family Hyracodontidae, known for long-legged, running rhinos. However, some experts now place it in its own family, Paraceratheriidae, based on its distinct features.

    Phylogenetic relationships of Paraceratherium with other rhinos, according to Tao Deng and colleagues, 2021. (CREDIT: Tao Deng, Xiaokang Lu, Shiqi Wang, Lawrence J. Flynn, Danhui Sun, Wen He & Shanqin Chen / Nature)

    Anatomy of a Giant

    Despite the incomplete fossil record, scientists have reconstructed much of Paraceratherium’s body. It stood nearly 16 feet tall at the shoulder, with a neck over 6 feet long and a skull that reached more than 4 feet. When stretching its neck, its head could reach up to 26 feet high—almost as tall as a three-story building.

    Weight estimates vary, but many scientists agree the largest individuals reached 15 to 24 tons. That’s significantly heavier than most dinosaurs like Tyrannosaurus rex, which topped out at around 9 tons. Unlike many dinosaurs with long tails, Paraceratherium had a more compact build, with its mass concentrated in a tall and thick torso.

    Its limbs were thick and straight like an elephant’s, ending in three broad toes with hoof-like tips. The leg bones, especially the femurs, were nearly five feet long. These limbs supported a massive ribcage and spine built for stability rather than speed. Its back sloped downward from the shoulders, giving it a distinctive profile.

    Holotype (HMV 2006) of Paraceratherium linxiaense sp. nov. Skull: a lateral view; b ventral view; c dorsal view; d anterior view; e occipital view. Mandible: f, h lateral view and medial view of left ramus, respectively; g occlusal view. Skull and mandible share the scale bar, but both anterior and nuchal views have an independent scale bar. (CREDIT: Tao Deng, Xiaokang Lu, Shiqi Wang, Lawrence J. Flynn, Danhui Sun, Wen He & Shanqin Chen / Nature)

    Feeding from the Treetops

    Paraceratherium lacked horns entirely, but it had long, tusk-like incisors and a skull with wide nasal openings. This structure hints at a short trunk or a flexible upper lip, like those found in tapirs, used for grabbing branches and leaves.

    Its teeth reveal it was a selective browser. The molars, each about the size of a human fist, were adapted for chewing soft leaves, twigs, and high vegetation. Its immense size allowed it to reach food sources that other herbivores couldn’t access, reducing competition.

    Researchers believe it needed to eat several hundred kilograms of plant material every day to maintain its energy. This diet shaped the landscape, as the animal likely cleared large areas while browsing—similar to how elephants affect their environments today.

    Researchers believe Paraceratherium needed to eat several hundred kilograms of plant material every day to maintain its energy. (CREDIT: Leogon / Deviant Art)

    Thriving in a Changing World

    Paraceratherium lived across a vast range of habitats. Fossils have been found in more than a dozen countries, including Pakistan, India, Kazakhstan, China, Mongolia, and Romania. This distribution reflects its ability to adapt to different climates, from subtropical forests to dry grasslands.

    During the Oligocene epoch, Earth’s climate was cooling. Woodlands and open grasslands spread across Eurasia, creating ideal environments for large plant-eaters. Seasonal rainfall and long dry periods meant that Paraceratherium likely migrated across large areas, possibly over 1,000 square kilometers, to find enough food.

    The Tibetan Plateau was still relatively low at the time, allowing easier movement between regions. This helped Paraceratherium expand its range and thrive for over 11 million years.

    Map showing localities of Paraceratherium species during the early (yellow) and late (red) Oligocene, according to Deng and colleagues, 2021. (CREDIT: Tao Deng, Xiaokang Lu, Shiqi Wang, Lawrence J. Flynn, Danhui Sun, Wen He & Shanqin Chen / Nature)

    Family Life and Survival

    Little is known about the animal’s social behavior, but scientists can make educated guesses based on its size and modern relatives. It probably lived alone or in small family groups. Large herds would have quickly exhausted local food supplies.

    Reproduction was slow, with long pregnancies and few offspring. Each calf would have required years of care before it could survive alone. This pattern, common among large mammals, makes populations more vulnerable to sudden changes in the environment.

    Adult Paraceratherium had few natural enemies due to its size. But the young were at risk. Carnivores like Hyaenodon gigas and “hell pigs” such as Paraentelodon may have preyed on calves or sick individuals.

    Climate Shift and Extinction

    Despite its success, Paraceratherium disappeared around 23 million years ago. Scientists believe several factors led to its extinction. As the Miocene epoch began, Earth’s climate grew cooler and drier. Forests shrank, replaced by open grasslands. These changes made life harder for a species that relied on high-browsing vegetation.

    Foraging herd of P. transouralicum, by Elizabeth Rungius Fulda, 1923. (CREDIT: Elizabeth Rungius Fulda)

    New herbivores, such as early elephants and ruminants, evolved better digestive systems for grasslands. These animals may have outcompeted Paraceratherium. Invasive species like gomphotheres may have changed habitats and food sources as they spread through Asia.

    Environmental shifts, combined with low birth rates and specialized feeding, likely made it hard for Paraceratherium to adapt. Its extinction marked the end of an era in mammalian evolution.

    New Tools, Fresh Discoveries

    Modern science has brought fresh insights into this ancient giant. Researchers now use digital scanning, 3D modeling, and isotope analysis to study its bones and teeth. These tools reveal details about its growth, diet, and environment that were once impossible to uncover.

    Bone microstructure shows it grew rapidly when young, then slowed as it aged—similar to modern elephants. Tooth chemistry indicates a preference for woodland plants and a relatively stable habitat.

    One major breakthrough came in 2021, when scientists described Paraceratherium linxiaense from China’s Linxia Basin. This specimen included a complete skull and helped refine understanding of the species’ size and shape.

    Genetic studies of modern rhinos have also helped confirm the evolutionary path of Paraceratherium, placing it in a now-extinct family that branched off early from the rhino lineage.

    The Legacy of a Lost Giant

    Paraceratherium’s bones tell a story of resilience, adaptation, and change. It lived through a time when mammals were evolving rapidly, stepping into ecological roles once filled by dinosaurs. As the largest land mammal ever known, it stretched the limits of what biology could support on land.

    Its disappearance reminds us how vulnerable even the mightiest creatures are to environmental shifts. Evolution doesn’t promise survival—only the ability to adapt. Though long extinct, Paraceratherium remains a powerful symbol of life’s potential and the fleeting nature of dominance on Earth.

    Through fossil digs, museum displays, and scientific research, this prehistoric giant continues to inspire awe and curiosity. Each new discovery deepens our understanding of the world it once ruled and the forces that shaped—and eventually ended—its reign.

    Continue Reading

  • Astronomers Find Five Rocky Planets Around a Small Red Dwarf, Including a Super-Earth in the Habitable Zone

    Astronomers Find Five Rocky Planets Around a Small Red Dwarf, Including a Super-Earth in the Habitable Zone

    Finding an exoplanet in a star’s habitable zone always generates interest. Each of these planets has a chance, even if it’s an infinitesimal one, of hosting simple life. While the possibility of detecting life on these distant planets is remote, finding them still teaches us about exoplanet populations and solar system architectures.

    When TESS found three planets orbiting the M-dwarf L 98-59 in 2019, then a fourth planet in 2021, the detections generated interest. Now that a fifth planet has been detected, a super-Earth in the habitable zone, the system is garnering renewed interest.

    The discovery is reported in research that will appear in The Astronomical Journal titled “Detailed Architecture of the L 98-59 System and Confirmation of a Fifth Planet in the Habitable Zone.” The lead author is Charles Cadieux, a researcher at the University of Montreal and Trottier Institute for Research on Exoplanets (IREx). The paper is currently available on arxiv.org.

    This figure shows transit data from TESS for the three innermost planets in the system, and radial velocity measurements for the two outermost planets. Image Credit: Cadieux et al. 2025.

    L 98-59 is an M3V star, a red dwarf, about 34.5 light-years away. It has about 0.3 solar masses and measures about 0.31 solar radii. Its first three planets, L 98-59 b, c, and d, were found by TESS with the transit method. The other two planets, e and f, were found with the radial velocity (RV) and transit timing variations (TTV) methods.

    “These new results paint the most complete picture we’ve ever had of the fascinating L 98-59 system,” said lead author Cadieux in a press release. “It’s a powerful demonstration of what we can achieve by combining data from space telescopes and high-precision instruments on Earth, and it gives us key targets for future atmospheric studies with the James Webb Space Telescope [JWST].”

    While the potentially habitable planet is intriguing, the overall architecture of the system might be even more intriguing. The system is a tightly-packed grouping of terrestrial planets with some dramatic compositional differences, despite their close proximity to each other. The system is reminiscent of the TRAPPIST-1 system discovered in 2016/17, which contains seven terrestrial planets. Its discovery generated a wave of interest in the space science and exoplanet community.

    “Multiplanetary systems offer a unique opportunity to study the outcomes of planetary formation and evolution within the same stellar environment,” the authors write in their paper. “One hypothesis is that planet formation around metal-rich M dwarfs may favor giant planets in ‘single’ configurations, while lower metallicity (and less massive disks) could lead to multiple rocky planets in stable, compact, and coplanar arrangements.”

    Above view of the L 98-59 planetary system. The Habitable Zone is shown in green for runaway/maximum greenhouse (conservative) and pale green for early recent Venus/early Mars (optimistic).Image Credit: Cadieux et al. 2025. Above view of the L 98-59 planetary system. The Habitable Zone is shown in green for runaway/maximum greenhouse (conservative) and pale green for early recent Venus/early Mars (optimistic).Image Credit: Cadieux et al. 2025.

    The innermost planet, L 98-59 b, has an Earth-like density, but is only about 84% its mass and half its size. It’s a rare sub-Earth with well-understood parameters. It takes only about 2.25 Earth days to orbit its star, and atmospheric study suggests it might be a very volcanically active world due to tidal heating.

    L 98-59 c is also likely volcanic due to tidal heating. It’s about 1.3 Earth radii and two Earth masses, and completes an orbit in about 3.7 Earth days. L 98-59 d has about 1.6 Earth radii, about 1.6 Earth masses, and an orbital period of about 7.4 days. It may be a water world, or hycean world. The fourth planet, L 98-59 e, has about 1.4 Earth radii, a minimum mass of about 2.8 Earth masses, and an orbital period of about 12.8 days.

    The newly-detected planet, L 98-59 f, is in the optimistic habitable zone of the star. It has a minimum mass of about 2.80 Earth masses, about 1.4 Earth radii, and follows a 28 day orbit.

    One of the interesting things about this system is that they follow near circular orbits. This means they’re amenable to atmospheric spectroscopic studies by the JWST or other telescopes. Observations also show that the three inner transiting planets have increasing water-mass fractions with orbital distance.

    This figure shows Mass–radius constraints on the L 98-59 planets (b: green, c: purple, d: red, e: blue, f: teal) with other exoplanets around M dwarfs in the background (gray points). Exoplanet mass on the x-axis and radius on the y-axis. The orange region delimits a degeneracy (H2- or H2O-rich) in composition. "The planets around L 98-59 are seemingly showing diverse compositions," the authors write. Image Credit: Cadieux et al. 2025. This figure shows Mass–radius constraints on the L 98-59 planets (b: green, c: purple, d: red, e: blue, f: teal) with other exoplanets around M dwarfs in the background (gray points). Exoplanet mass on the x-axis and radius on the y-axis. The orange region delimits a degeneracy (H2- or H2O-rich) in composition. “The planets around L 98-59 are seemingly showing diverse compositions,” the authors write. Image Credit: Cadieux et al. 2025.

    “With its diversity of rocky worlds and range of planetary compositions, L 98-59 offers a unique laboratory to address some of the field’s most pressing questions: What are super-Earths and sub-Neptunes made of? Do planets form differently around small stars? Can rocky planets around red dwarfs retain atmospheres over time?” said René Doyon, co-author of the study, who is a professor at the University of Montreal and the Director of IREx.

    “Finding a temperate planet in such a compact system makes this discovery particularly exciting,” said lead author Cadieux. “It highlights the remarkable diversity of exoplanetary systems and strengthens the case for studying potentially habitable worlds around low-mass stars.”

    Exoplanet habitability around low mass M-dwarfs is a contentious idea. Since they’re so dim, their habitable zones are close to the stars. This creates a couple of potential obstacles to habitability as scientists understand it.

    Because of their proximity to their stars, these planets may be tidally-locked. It’s difficult to say whether that’s a serious barrier to habitability, or if an exoplanet’s atmosphere would somehow spread the heat around. It’s possible that habitable zones on these planets are limited to a pole-to-pole terminator zone around the planet’s surface that is temperate.

    M-dwarfs are also known for their powerful flaring, which can strip atmospheres away. Without an atmosphere, an exoplanet is unlikely to be habitable, though scientists can’t completely eliminate the possibility.

    On the other hand, M-dwarfs are extremely long-lived stars that burn their fuel very slowly. That means they offer long-lived stability to any planets in their habitable zones.

    This system will no doubt attract further attention from the exoplanet science community. In fact, further study with the JWST is already underway. “The atmospheric characterization of the L 98-59 planets is already underway with JWST, using both transmission and emission spectroscopy,” the authors write. ” Such comprehensive characterization is key to advancing our understanding of planet formation and evolution around low-mass stars.”

    “With these new results, L 98-59 joins the select group of nearby, compact planetary systems that we hope to understand in greater detail over the coming years,” says Alexandrine L’Heureux, co-author of the study and Ph.D. student at the University of Montreal. “It’s exciting to see it stand alongside systems like TRAPPIST-1 in our quest to unlock the nature and formation of small planets orbiting red dwarf stars.”

    Continue Reading

  • Representational Drift of Hippocampal Neurons Alters Spatial Memory in Mice – Genetic Engineering and Biotechnology News

    1. Representational Drift of Hippocampal Neurons Alters Spatial Memory in Mice  Genetic Engineering and Biotechnology News
    2. Hippocampal representations drift in stable multisensory environments  Nature
    3. Map-making neurons change even in familiar settings, study finds  Illinois News Bureau
    4. Neurons shift during repeated navigation of identical paths  News-Medical

    Continue Reading

  • NASA Welcomes Senegal as Newest Artemis Accords Signatory

    NASA Welcomes Senegal as Newest Artemis Accords Signatory

    Senegal signed the Artemis Accords Thursday during a ceremony hosted by NASA at the agency’s headquarters in Washington, becoming the latest nation to commit to the responsible exploration of space for all humanity.

    “Following a meeting between Senegal President Faye and President Trump, today, NASA built upon the strong relations between our two nations as the Senegalese Agency for Space Studies signed the Artemis Accords,” said acting NASA Administrator Sean Duffy. “With Senegal as the 56th signatory, I am proud to further President Trump’s strong legacy of global cooperation in space.”

    Director General of the Senegalese space agency (ASES) Maram Kairé signed the Artemis Accords on behalf of Senegal. Jonathan Pratt, senior bureau official for African Affairs at the U.S. Department of State, and Abdoul Wahab Haidara, ambassador of Senegal to the United States, also participated in the event.

    “Senegal’s adherence to the Artemis Accords reflects our commitment to a multilateral, responsible, and transparent approach to space,” said Kairé. “This signature marks a meaningful step in our space diplomacy and in our ambition to contribute to the peaceful exploration of outer space.”

    The Artemis Accords signing ceremony took place two weeks after President Trump’s meeting in Washington with Senegal’s President Bassirou Diomaye Faye and other countries of Africa focused on U.S.-Africa engagement.

    Astronomers from Senegal have supported NASA missions by participating in multiple observations when asteroids or planets pass in front of stars, casting shadows on Earth. In 2021, NASA also collaborated with Kairé and a group of astronomers for a ground observation campaign in Senegal. As the asteroid Orus passed in front of a star, they positioned telescopes along the path of the asteroid’s shadow to estimate its shape and size. NASA’s Lucy spacecraft will approach Orus in 2028, as part of its mission to explore Jupiter’s Trojan asteroids.

    In 2020, during the first Trump Administration, the United States, led by NASA and the U.S. Department of State, joined with seven other founding nations to establish the Artemis Accords, responding to the growing interest in lunar activities by both governments and private companies.

    The accords introduced the first set of practical principles aimed at enhancing the safety, transparency, and coordination of civil space exploration on the Moon, Mars, and beyond.

    Signing the Artemis Accords means to explore peaceably and transparently, to render aid to those in need, to ensure unrestricted access to scientific data that all of humanity can learn from, to ensure activities do not interfere with those of others, to preserve historically significant sites and artifacts, and to develop best practices for how to conduct space exploration activities for the benefit of all.

    More countries are expected to sign the Artemis Accords in the months and years ahead, as NASA continues its work to establish a safe, peaceful, and prosperous future in space.

    Learn more about the Artemis Accords at:

    https://www.nasa.gov/artemis-accords

    -end-

    Bethany Stevens / Elizabeth Shaw
    Headquarters, Washington
    202-358-1600
    bethany.c.stevens@nasa.gov / elizabeth.a.shaw@nasa.gov

    Continue Reading

  • High-Resolution Mapping Reveals Antarctic Canyons’ True Scale

    High-Resolution Mapping Reveals Antarctic Canyons’ True Scale

    What can submarine canyons teach scientists about the Earth’s oceans? This is what a recent study published in Marine Geology hopes to address as a team of scientists conducted the most extensive investigation into Antarctic submarine canyons with the goal of building on previous studies while attempting to discover new canyons. This study has the potential to help scientists better understand how submarine canyons impact ocean circulation and climate change, along with finding life in new and exciting locations.

    For the study, the researchers used database maps to create the most comprehensive catalog of submarine canyons while greatly building on previous studies. To accomplish this, the team divided Antarctica into ten geographic zones with the goal of mapping submarine canyons and gullies that exist on the Southern Ocean floor. In the end, the researchers successfully identified five times the number of submarine canyons than previous studies, including a total of 322 canyon networks comprised of 3,291 streams.

    “Some of the submarine canyons we analyzed reach depths of over 4,000 meters [13,000 feet],” said Dr. David Amblàs, who is an associate professor and geologist at the University of Barcelona and co-author on the study. “The most spectacular of these are in East Antarctica, which is characterized by complex, branching canyon systems. The systems often begin with multiple canyon heads near the edge of the continental shelf and converge into a single main channel that descends into the deep ocean, crossing the sharp, steep gradients of the continental slope.”

    The researchers note that better understanding of submarine canyons could help improve climate change models, as the former regulates ocean circulation, thus helping produce more accurate climate predictions.

    What new discoveries about submarine canyons will researchers make in the coming years and decades? Only time will tell, and this is why we science!

    As always, keep doing science & keep looking up!

    Sources: Marine Geology, EurekAlert!

    Featured Image Credit: MARC CERDÀ – UNIVERSITY OF BARCELONA

    Continue Reading

  • Enhancing Mars Life Explorer (MLE) With True Agnostic Life Detection Capabilities

    Enhancing Mars Life Explorer (MLE) With True Agnostic Life Detection Capabilities

    The Mars Life Explorer (MLE) mission concept offers a critical opportunity to investigate whether extant life exists within the mid-latitude ice deposits of Mars.

    However, MLE’s current science traceability matrix emphasizes habitability assessment and organic chemistry over direct life detection. As crewed missions to Mars may occur as early as 2040, the window for uncontaminated robotic exploration is rapidly closing.

    A high-confidence determination of Martian life must be achieved before irreversible anthropogenic contamination compromises scientific integrity.

    The Mars Life Explorer (MLE) mission concept report, NASA

    This paper evaluates the scientific, technical, and policy limitations of the current MLE architecture and recommends specific instrumentation upgrades and governance measures necessary to enable definitive and agnostic life detection while safeguarding planetary protection.

    Gabriella Rizzo, Jan Spacek

    Comments: Prepared as a white paper submission for the MEPAG Search for Life-Science Analysis Group (SFL-SAG) workshop, July 2025
    Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)
    Cite as: arXiv:2507.16866 [astro-ph.IM] (or arXiv:2507.16866v1 [astro-ph.IM] for this version)
    https://doi.org/10.48550/arXiv.2507.16866
    Focus to learn more
    Submission history
    From: Gabriella Rizzo
    [v1] Tue, 22 Jul 2025 01:24:41 UTC (240 KB)
    https://arxiv.org/abs/2507.16866

    Astrobiology

    Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

    Continue Reading

  • Fine-tuning The Complex Organic Molecule Formation: Sulfur And CO Ice As Regulators Of Surface Chemistry

    Fine-tuning The Complex Organic Molecule Formation: Sulfur And CO Ice As Regulators Of Surface Chemistry

    Visual extinction maps of the observed regions. Contours in the Barnard 1b map (left) correspond to [7, 14, 21, 28, 35, 42, 49, 56, 63, 70] mag levels. The contours in the IC 348 map (right) correspond to [6, 9, 12, 15, 18, 21, 24] mag levels. These maps were obtained from the τ850 optical depth maps in Zari et al. (2016) applying the K-band to V-band extinction ratio of ∼ 1/16 (Nishiyama et al. 2008). The crosses mark the pointings from where data was taken. Selected spectra of CH3OH lines at 90 GHz (Table 2) and H2S 11,0 → 10,1 line observed at different offsets are included in the maps. — astro-ph.GA

    Grain-surface chemistry plays a crucial role in the formation of molecules of astrobiological interest, including H2S and complex organic molecules (COMs).

    They are commonly observed in the gas phase toward star-forming regions, but their detection in ices remains limited. Combining gas-phase observations with chemical modeling is therefore essential for advancing our understanding of their chemistry.

    In this paper we investigate the factors that promote or hinder molecular complexity combining gas-phase observations of CH3OH, H2S, OCS, N2H+, and C18O with chemical modeling in two dense cores: Barnard-1b and IC348. We observed millimeter emission lines of CH3OH, H2S, OCS, N2H+, and C18O along strips using the IRAM 30m and Yebes 40m telescopes. We used the gas-grain chemical model Nautilus to reproduce the observed abundance profiles adjusting parameters such as initial sulfur abundances and binding energies.

    H2S, N2H+ and C18O gas-phase abundances vary up to one order of magnitude towards the extinction peak. CH3OH abundance remains quite uniform. These abundances can only be reproduced assuming a decreasing sulfur budget, which lowers H2S and enhances CH3OH abundances. Decreasing binding energies, which are expected in CO-rich apolar ices, are also required.

    The sulfur depletion required by H2S is generally higher than that required by CH3OH, suggesting unknown sulfur sinks. These findings highlight the intricate relationship between sulfur chemistry and COM formation, driven by the competition between sulfur and CO for hydrogen atoms.

    Our study emphasizes that the growth of CO ice and the progressive sequestration of hydrogen atoms by sulfur are critical in determining whether chemical complexity can develop, providing key insights into the early stages of star and planet formation.

    D. Navarro-Almaida, A. Taillard, A. Fuente, P. Caselli, R. Martín-Doménech, J. J. Miranzo-Pastor

    Comments: 46 pages and 37 figures. Accepted for publication in Astronomy and Astrophysics
    Subjects: Astrophysics of Galaxies (astro-ph.GA)
    Cite as: arXiv:2507.17595 [astro-ph.GA] (or arXiv:2507.17595v1 [astro-ph.GA] for this version)
    https://doi.org/10.48550/arXiv.2507.17595
    Focus to learn more Submission history From: David Navarro-Almaida
    [v1] Wed, 23 Jul 2025 15:27:16 UTC (2,364 KB)
    https://arxiv.org/abs/2507.17595

    Astrobiology, Astrochemistry,

    Continue Reading