Science
Hot Jupiter Rising: A Planet’s Remarkable Transformation
This artist’s impression shows a Jupiter-like exoplanet that is on its way to becoming a hot Jupiter — a large, Jupiter-like exoplanet that orbits very close to its star. Credit: International Gemini Observatory/NOIRLab/NSF/AURA/J. da Silva/Spaceengine/M. Zamani Planet’s wild orbit offers clues to how such large, hot planets take shape. A team of astronomers has discovered a juvenile planet, TIC 241249530 b, which is transitioning into a hot Jupiter. This planet, in a unique eccentric and retrograde orbit, is a key to understanding the dynamic processes that transform distant, icy giants into blazing, star-hugging worlds. Hot Jupiters are some of the most extreme planets in the galaxy. These scorching worlds are as massive as Jupiter, and they swing wildly close to their star, whirling around in a few days compared to our own gas giant’s leisurely 4,000-day orbit around the sun. Scientists suspect, though, that hot Jupiters weren’t always so hot and in fact may have formed as “cold Jupiters,” in more frigid, distant environs. But how they evolved to be the star-hugging gas giants that astronomers observe today is a big unknown. Discovering a Progenitor Planet Now, astronomers at MIT, Penn State University, and elsewhere have discovered a hot Jupiter “progenitor” — a sort of juvenile planet that is in the midst of becoming a hot Jupiter. And its orbit is providing some answers to how hot Jupiters evolve. The new planet, which astronomers labeled TIC 241249530 b, orbits a star that is about 1,100 light-years from Earth. The planet circles its star in a highly “eccentric” orbit, meaning that it comes extremely close to the star before slinging far out, then doubling back, in a narrow, elliptical circuit. If the planet was part of our solar system, it would come 10 times closer to the sun than Mercury, before hurtling out, just past Earth, then back around. By the scientists’ estimates, the planet’s stretched-out orbit has the highest eccentricity of any planet detected to date. This illustration shows the orbit of the newly discovered Jupiter-like exoplanet named TIC 241249530 b, shown in comparison to the orbits of Mercury and Earth in our own Solar System. If this planet were part of our solar system, its orbit would stretch from its closest approach, 10 times closer to the Sun than Mercury, all the way out to its most distant extent at Earth’s distance. Credit: NOIRLab/NSF/AURA/R. Proctor Unique Orbital Dynamics The new planet’s orbit is also unique in its “retrograde” orientation. Unlike the Earth and other planets in the solar system, which orbit in the same direction as the sun spins, the new planet travels in a direction that is counter to its star’s rotation. The team ran simulations of orbital dynamics and found that the planet’s highly eccentric and retrograde orbit are signs that it is likely evolving into a hot Jupiter, through “high-eccentricity migration” — a process by which a planet’s orbit wobbles and progressively shrinks as it interacts with another star or planet on a much wider orbit. In the case of TIC 241249530 b, the researchers determined that the planet orbits around a primary star that itself orbits around a secondary star, as part of a stellar binary system. The interactions between the two orbits — of the planet and its star — have caused the planet to gradually migrate closer to its star over time. Evolution of a Hot Jupiter The planet’s orbit is currently elliptical in shape, and the planet takes about 167 days to complete a lap around its star. The researchers predict that in 1 billion years, the planet will migrate into a much tighter, circular orbit, when it will then circle its star every few days. At that point, the planet will have fully evolved into a hot Jupiter. “This new planet supports the theory that high eccentricity migration should account for some fraction of hot Jupiters,” says Sarah Millholland, assistant professor of physics in MIT’s Kavli Institute for Astrophysics and Space Research. “We think that when this planet formed, it would have been a frigid world. And because of the dramatic orbital dynamics, it will become a hot Jupiter in about a billion years, with temperatures of several thousand kelvin. So it’s a huge shift from where it started.” Millholland and her colleagues have published their findings recently in the journal Nature. Her co-authors are MIT undergraduate Haedam Im, lead author Arvind Gupta of Penn State University and NSF NOIRLab, and collaborators at multiple other universities, institutions, and observatories. “Radical Seasons” The new planet was first spotted in data taken by NASA’s Transiting Exoplanet Survey Satellite (TESS), an MIT-led mission that monitors the brightness of nearby stars for “transits,” or brief dips in starlight that could signal the presence of a planet passing in front of, and temporarily blocking, a star’s light. On Jan. 12, 2020, TESS picked up a possible transit of the star TIC 241249530. Gupta and his colleagues at Penn State determined that the transit was consistent with a Jupiter-sized planet crossing in front of the star. They then acquired measurements from other observatories of the star’s radial velocity, which estimates a star’s wobble, or the degree to which it moves back and forth, in response to other nearby objects that might gravitationally tug on the star. Those measurements confirmed that a Jupiter-sized planet was orbiting the star and that its orbit was highly eccentric, bringing the planet extremely close to the star before flinging it far out. Prior to this detection, astronomers had known of only one other planet, HD 80606 b, that was thought to be an early hot Jupiter. That planet, discovered in 2001, held the record for having the highest eccentricity, until now. “This new planet experiences really dramatic changes in starlight throughout its orbit,” Millholland says. “There must be really radical seasons and an absolutely scorched atmosphere every time it passes close to the star.” “Dance of Orbits” How could a planet have fallen into such an extreme orbit? And how might its eccentricity evolve over time? For answers, Im and Millholland ran simulations of planetary orbital dynamics to model how the planet may have evolved throughout its history and how it might carry on over hundreds of millions of years. The team modeled the gravitational interactions between the planet, its star, and the second nearby star. Gupta and his colleagues had observed that the two stars orbit each other in a binary system, while the planet is simultaneously orbiting the closer star. The configuration of the two orbits is somewhat like a circus performer twirling a hula hoop around her waist, while spinning a second hula hoop around her wrist. Millholland and Im ran multiple simulations, each with a different set of starting conditions, to see which condition, when run forward over several billions of years, produced the configuration of planetary and stellar orbits that Gupta’s team observed in the present day. They then ran the best match even further into the future to predict how the system will evolve over the next several billion years. These simulations revealed that the new planet is likely in the midst of evolving into a hot Jupiter: Several billion years ago, the planet formed as a cold Jupiter, far from its star, in a region cold enough to condense and take shape. Newly formed, the planet likely orbited the star in a circular path. This conventional orbit, however, gradually stretched and grew eccentric, as it experienced gravitational forces from the star’s misaligned orbit with its second, binary star. “It’s a pretty extreme process in that the changes to the planet’s orbit are massive,” Millholland says. “It’s a big dance of orbits that’s happening over billions of years, and the planet’s just going along for the ride.” In another billion years, the simulations show that the planet’s orbit will stabilize in a close-in, circular path around its star. “Then, the planet will fully become a hot Jupiter,” Millholland says. The team’s observations, along with their simulations of the planet’s evolution, support the theory that hot Jupiters can form through high eccentricity migration, a process by which a planet gradually moves into place via extreme changes to its orbit over time. “It’s clear not only from this, but other statistical studies too, that high eccentricity migration should account for some fraction of hot Jupiters,” Millholland notes. “This system highlights how incredibly diverse exoplanets can be. They are mysterious other worlds that can have wild orbits that tell a story of how they got that way and where they’re going. For this planet, it’s not quite finished its journey yet.” “It is really hard to catch these hot Jupiter progenitors ‘in the act’ as they undergo their super eccentric episodes, so it is very exciting to find a system that undergoes this process,” says Smadar Naoz, a professor of physics and astronomy at the University of California at Los Angeles, who was not involved with the study. “I believe that this discovery opens the door to a deeper understanding of the birth configuration of the exoplanetary system.” For more on this research: Reference: “A hot-Jupiter progenitor on a super-eccentric retrograde orbit” by Arvind F. Gupta, Sarah C. Millholland, Haedam Im, Jiayin Dong, Jonathan M. Jackson, Ilaria Carleo, Jessica Libby-Roberts, Megan Delamer, Mark R. Giovinazzi, Andrea S. J. Lin, Shubham Kanodia, Xian-Yu Wang, Keivan Stassun, Thomas Masseron, Diana Dragomir, Suvrath Mahadevan, Jason Wright, Jaime A. Alvarado-Montes, Chad Bender, Cullen H. Blake, Douglas Caldwell, Caleb I. Cañas, William D. Cochran, Paul Dalba, Mark E. Everett, Pipa Fernandez, Eli Golub, Bruno Guillet, Samuel Halverson, Leslie Hebb, Jesus Higuera, Chelsea X. Huang, Jessica Klusmeyer, Rachel Knight, Liouba Leroux, Sarah E. Logsdon, Margaret Loose, Michael W. McElwain, Andrew Monson, Joe P. Ninan, Grzegorz Nowak, Enric Palle, Yatrik Patel, Joshua Pepper, Michael Primm, Jayadev Rajagopal, Paul Robertson, Arpita Roy, Donald P. Schneider, Christian Schwab, Heidi Schweiker, Lauren Sgro, Masao Shimizu, Georges Simard, Guðmundur Stefánsson, Daniel J. Stevens, Steven Villanueva, John Wisniewski, Stefan Will and Carl Ziegler, 17 July 2024, Nature.DOI: 10.1038/s41586-024-07688-3
Iron Twist: Slower Ocean Currents Could Unexpectedly Accelerate Climate Warming
As the ocean gets weaker, it could release more carbon from the deep ocean into the atmosphere — rather than less, as some have predicted. Credit: MIT News; iStock New research challenges current thinking on the ocean’s role in storing carbon. A new MIT study challenges previous understanding of the ocean’s role in climate change by demonstrating that weaker oceanic circulation might not decrease, but instead increase atmospheric CO2 levels. This finding arises from the interaction of various oceanic components like iron, ligands, and microorganisms, which together may lead to an unexpected rise in CO2 if ocean circulation diminishes. Ocean Circulation and Climate Change As climate change advances, the ocean’s overturning circulation is predicted to weaken substantially. With such a slowdown, scientists estimate the ocean will pull down less carbon dioxide from the atmosphere. However, a slower circulation should also dredge up less carbon from the deep ocean that would otherwise be released back into the atmosphere. On balance, the ocean should maintain its role in reducing carbon emissions from the atmosphere, if at a slower pace. Rethinking Oceanic Carbon Storage However, a new study by an MIT researcher finds that scientists may have to rethink the relationship between the ocean’s circulation and its long-term capacity to store carbon. As the ocean gets weaker, it could release more carbon from the deep ocean into the atmosphere instead. The reason has to do with a previously uncharacterized feedback between the ocean’s available iron, upwelling carbon and nutrients, surface microorganisms, and a little-known class of molecules known generally as “ligands.” When the ocean circulates more slowly, all these players interact in a self-perpetuating cycle that ultimately increases the amount of carbon that the ocean outgases back to the atmosphere. Implications for Climate Action “By isolating the impact of this feedback, we see a fundamentally different relationship between ocean circulation and atmospheric carbon levels, with implications for the climate,” says study author Jonathan Lauderdale, a research scientist in MIT’s Department of Earth, Atmospheric, and Planetary Sciences. “What we thought is going on in the ocean is completely overturned.” Lauderdale says the findings show that “we can’t count on the ocean to store carbon in the deep ocean in response to future changes in circulation. We must be proactive in cutting emissions now, rather than relying on these natural processes to buy us time to mitigate climate change.” His study was published recently in the journal Nature Communications. Reevaluating Phytoplankton’s Role In 2020, Lauderdale led a study that explored ocean nutrients, marine organisms, and iron, and how their interactions influence the growth of phytoplankton around the world. Phytoplankton are microscopic, plant-like organisms that live on the ocean surface and consume a diet of carbon and nutrients that upwell from the deep ocean and iron that drifts in from desert dust. The more phytoplankton that can grow, the more carbon dioxide they can absorb from the atmosphere via photosynthesis, and this plays a large role in the ocean’s ability to sequester carbon. For the 2020 study, the team developed a simple “box” model, representing conditions in different parts of the ocean as general boxes, each with a different balance of nutrients, iron, and ligands — organic molecules that are thought to be byproducts of phytoplankton. The team modeled a general flow between the boxes to represent the ocean’s larger circulation — the way seawater sinks, then is buoyed back up to the surface in different parts of the world. Challenges of Ocean Seeding This modeling revealed that, even if scientists were to “seed” the oceans with extra iron, that iron wouldn’t have much of an effect on global phytoplankton growth. The reason was due to a limit set by ligands. It turns out that, if left on its own, iron is insoluble in the ocean and therefore unavailable to phytoplankton. Iron only becomes soluble at “useful” levels when linked with ligands, which keep iron in a form that plankton can consume. Lauderdale found that adding iron to one ocean region to consume additional nutrients robs other regions of nutrients that phytoplankton there need to grow. This lowers the production of ligands and the supply of iron back to the original ocean region, limiting the amount of extra carbon that would be taken up from the atmosphere. Reversing Assumptions in Ocean Modeling Once the team published their study, Lauderdale worked the box model into a form that he could make publicly accessible, including ocean and atmosphere carbon exchange and extending the boxes to represent more diverse environments, such as conditions similar to the Pacific, the North Atlantic, and the Southern Ocean. In the process, he tested other interactions within the model, including the effect of varying ocean circulation. He ran the model with different circulation strengths, expecting to see less atmospheric carbon dioxide with weaker ocean overturning — a relationship that previous studies have supported, dating back to the 1980s. But what he found instead was a clear and opposite trend: The weaker the ocean’s circulation, the more CO2 built up in the atmosphere. New Insights from Variable Ligand Concentrations “I thought there was some mistake,” Lauderdale recalls. “Why were atmospheric carbon levels trending the wrong way?” When he checked the model, he found that the parameter describing ocean ligands had been left “on” as a variable. In other words, the model was calculating ligand concentrations as changing from one ocean region to another. On a hunch, Lauderdale turned this parameter “off,” which set ligand concentrations as constant in every modeled ocean environment, an assumption that many ocean models typically make. That one change reversed the trend, back to the assumed relationship: A weaker circulation led to reduced atmospheric carbon dioxide. But which trend was closer to the truth? Lauderdale looked to the scant available data on ocean ligands to see whether their concentrations were more constant or variable in the actual ocean. He found confirmation in GEOTRACES, an international study that coordinates measurements of trace elements and isotopes across the world’s oceans, that scientists can use to compare concentrations from region to region. Indeed, the molecules’ concentrations varied. If ligand concentrations do change from one region to another, then his surprise new result was likely representative of the real ocean: A weaker circulation leads to more carbon dioxide in the atmosphere. “It’s this one weird trick that changed everything,” Lauderdale says. “The ligand switch has revealed this completely different relationship between ocean circulation and atmospheric CO2 that we thought we understood pretty well.” Exploring the Effects of Circulation on Climate To see what might explain the overturned trend, Lauderdale analyzed biological activity and carbon, nutrient, iron, and ligand concentrations from the ocean model under different circulation strengths, comparing scenarios where ligands were variable or constant across the various boxes. This revealed a new feedback: The weaker the ocean’s circulation, the less carbon and nutrients the ocean pulls up from the deep. Any phytoplankton at the surface would then have fewer resources to grow and would produce fewer byproducts (including ligands) as a result. With fewer ligands available, less iron at the surface would be usable, further reducing the phytoplankton population. There would then be fewer phytoplankton available to absorb carbon dioxide from the atmosphere and consume upwelled carbon from the deep ocean. “My work shows that we need to look more carefully at how ocean biology can affect the climate,” Lauderdale points out. “Some climate models predict a 30 percent slowdown in the ocean circulation due to melting ice sheets, particularly around Antarctica. This huge slowdown in overturning circulation could actually be a big problem: In addition to a host of other climate issues, not only would the ocean take up less anthropogenic CO2 from the atmosphere, but that could be amplified by a net outgassing of deep ocean carbon, leading to an unanticipated increase in atmospheric CO2 and unexpected further climate warming.” Reference: “Ocean iron cycle feedbacks decouple atmospheric CO2 from meridional overturning circulation changes” by Jonathan Maitland Lauderdale, 8 July 2024, Nature Communications.DOI: 10.1038/s41467-024-49274-1
Unprecedented Air Stability: New Molecules Promise Longer Battery Life
Researchers developed new air-stable organic molecules for use in cost-effective energy storage, demonstrating practical and sustainable battery performance over extended cycles in a recent Nature Sustainability study. Credit: DICP New naphthalene derivatives improve the air stability and cycling performance of ORAMs in AOFBs, potentially enhancing sustainable energy storage. Organic redox-active molecules (ORAMs) are plentiful and varied, presenting great potential for affordable and sustainable energy storage, especially in aqueous organic flow batteries (AOFBs). However, maintaining the stability of ORAMs during charging and discharging is crucial, as side reactions can deactivate them, rendering them inactive. The air stability of many ORAMs also poses a significant challenge, hindering their practical application. Recently, a research group led by Prof. Xianfeng Li and Prof. Changkun Zhang from the Dalian Institute of Chemical Physics (DlCP) of the Chinese Academy of Sciences (CAS) developed novel naphthalene derivatives with active hydroxyls and dimethylamine scaffolds that were stable in air and served as effective catholytes for AOFBs. This study, published in Nature Sustainability, demonstrates that these novel ORAMs can achieve long-term stable cycling even under air-atmosphere conditions. Challenges and Solutions for ORAM Stability ORAMs are challenged with instability and high cost, particularly when used without inert gas protection. This can lead to irreversible capacity loss and a reduced battery lifespan. In this study, the researchers synthesized active naphthalene derivatives using a scalable approach that combined chemical and in situ electrochemical methods. This approach simplified the purification process and significantly reduced the cost of molecular synthesis. A pilot-scale naphthalene-based flow stack. Credit: DICP Moreover, the researchers demonstrated specific structure changes in the naphthalene derivatives during the electrochemical process. The as-prepared naphthalene derivatives feature a multisubstituted framework with hydrophilic alkylamine scaffolds, which not only protect against potential side reactions but also improve their solubility in aqueous electrolytes. The 1.5 mol/L naphthalene-based AOFB displayed stable cycling performance for 850 cycles (about 40 days) with a capacity of 50 Ah L-1. Remarkably, even with continuous air flow in the catholyte, the naphthalene-based AOFB could run smoothly for approximately 600 cycles (about 22 days) without capacity and efficiency decay. This demonstrated that the naphthalene-based catholyte had excellent air stability. Furthermore, the researchers scaled up the preparation of naphthalene derivatives to the kilogram scale (5 kg per pot). Pilot-scale battery stacks containing these naphthalene derivatives achieved an average system capacity of approximately 330 Ah. They exhibited remarkable cycling stability over 270 cycles (about 27 days), with a capacity retention of 99.95% per cycle. “This study is expected to open a new field in the design of air-stable molecular for sustainable and air-stable electrochemical energy storage,” said Prof. Li. Reference: “Air-stable naphthalene derivative-based electrolytes for sustainable aqueous flow batteries” by Ziming Zhao, Tianyu Li, Changkun Zhang, Mengqi Zhang, Shenghai Li and Xianfeng Li, 28 August 2024, Nature Sustainability.DOI: 10.1038/s41893-024-01415-6
Scientists Discover Peculiar New Species of Dragonfish in Antarctica
Akarotaxis gouldae, a newly discovered species of Antarctic dragonfish, was named in honor of the recently decommissioned Antarctic research supply vessel Laurence M. Gould. Credit: Andrew Corso Newly identified Antarctic dragonfish, Akarotaxis gouldae, displays unique traits and faces threats from climate change and fishing, underscoring conservation challenges. Researchers at William & Mary’s Virginia Institute of Marine Science (VIMS) have discovered a new species of Antarctic dragonfish in waters off the western Antarctic Peninsula. The species, named Akarotaxis gouldae or Banded Dragonfish, exemplifies both the unknown biodiversity and fragile state of the Antarctic ecosystem. Genetic Analysis and Species Identification Akarotaxis gouldae, described in the journal Zootaxa, was initially identified through genetic analysis. Larval specimens collected off the coast of Antarctica while trawling for zooplankton were originally thought to be Akarotaxis nudiceps, a closely related dragonfish. However, after comparing their DNA to Akarotaxis nudiceps specimens housed in collections at VIMS, Yale University and the Muséum national d’Histoire naturelle in Paris, France, significant variations in mitochondrial gene regions suggested the larval samples were a species unto themselves. Adult samples of Akarotaxis gouldae (left) compared to adult samples of Akarotaxis nudiceps (right) show subtle yet distinct morphological differences, including the presence of two bands on the bodies of Akarotaxis gouldae as well as a shorter snouts and jaws. Credit: Andrew Corso Significance of Morphological Examination Lead author Andrew Corso conducted the research while earning his Ph.D. at W&M’s Batten School of Coastal & Marine Sciences at VIMS under faculty advisors Eric Hilton and Deborah Steinberg. Using the DNA evidence as their guide, Corso and his colleagues requested the examination of adult Akarotaxis gouldae samples from numerous ichthyology collections around the world. Morphological differences became apparent between the two species once the adult samples were compared. “There are two distinct bands on the sides of adult Akarotaxis gouldae that are not present on Akarotaxis nudiceps, so we were surprised that the species already existed in collections but had been previously overlooked,” said Corso. “In the world of fish taxonomy, it’s becoming common to distinguish species with genetics alone. Genetic testing is an extremely valuable tool, but our discovery highlights the importance of early life stage morphology and natural history collections like those at VIMS and other institutions.” This map shows where larval samples of Akarotaxis gouldae (yellow arrows) were collected along the western Antarctic Peninsula. Compared to Akarotaxis nudiceps, Akarotaxis gouldae appear to have a much more limited range. Credit: Andrew Corso Evolutionary Insights from Genetic Studies Genetic testing also revealed evolutionary clues. Using a process called time-calibrated phylogeny, Corso and coauthor Thomas Desvignes from the Institute of Neuroscience at the University of Oregon estimated that Akarotaxis gouldae diverged as a separate species approximately 780,000 years ago. During this time, most of the Southern Ocean was covered in glaciers. “This process essentially looks at the rate of genetic mutations as a guide for a species’ evolutionary history,” said Corso. “We hypothesize that a population of dragonfishes may have become isolated within deep trenches under glaciers, surviving on food pushed in by the moving ice. Once the glaciers retreated, this subpopulation had become distinct enough to be reproductively incompatible with Akarotaxis nudiceps.” The ARSV Laurence M. Gould was retired from NSF operations in April. It was one of two research supply vessels supporting U.S. Antarctic research. Credit: Kharis Shrage Conservation Concerns for the Newly Discovered Species Presently, Antarctic dragonfishes are poorly understood because they live in the remote Southern Ocean and spend most of their adult lives in deep water. Prior research suggests these fishes engage in nest guarding in shallower coastal waters, and their offspring remain closer to the surface during their larval stage. Examination of female ovaries showed limited reproductive capacity. While Akarotaxis nudiceps are distributed in waters surrounding the southern continent, analysis of larval sampling data suggests the distribution of Akarotaxis gouldae is limited to the waters around the western Antarctic Peninsula. Dragonfishes are important prey items for many species, including Antarctica’s iconic penguins, whose populations have declined dramatically in recent decades. A 2022 study by Corso linked warming waters and reduced ice in the Southern Ocean to declines in Antarctic silverfish populations. “Akarotaxis gouldae appear to have one of the smallest ranges of any fish endemic to the Southern Ocean,” said Corso. “This limited range combined with their low reproductive capacity and the presence of early life stages in shallower waters suggest that this is a vulnerable species that could be impacted by the krill fishery.” The waters surrounding the western Antarctic Peninsula are heavily targeted by the international Antarctic krill fishery, which is managed by the Conservation of Antarctic Marine Living Resources (CCAMLR). Commercial fishing vessels trawl for krill in waters between 0-250 meters deep, and CCAMLR emphasizes the difficulties in correctly identifying larval and juvenile finfish bycatch in these operations. “Since we know so little about the biodiversity of this area, we feel caution should be taken in extracting resources until we have a better understanding of the impact to the greater ecosystem,” said Corso. Implications of the Discovery and Naming the New Species The ARSV Laurence M. Gould was named after Laurence McKinnley Gould, the chief scientist on the first expedition to Antarctica. While most might assume Akarotaxis gouldae was also named in honor of the famous geologist, the researchers rather decided to honor the vessel for its significant scientific contributions of it and its crew. Challenges and Future Directions in Antarctic Research The ARSV Laurence M. Gould supported the U.S. National Science Foundation’s Antarctic Program from 1997 until the non-renewal of its charter in April of this year. It was one of two U.S. ARSVs dedicated to studying the Southern Ocean. While a replacement vessel is in the design phase, the U.S. National Science Foundation explained the Gould’s charter was not renewed for economic reasons as well as shifting research priorities of the U.S. Antarctic Program. The ARSV Laurence M. Gould and its crew provided significant support to Antarctic research carried out by VIMS and other institutions. Corso’s advisor Steinberg conducts long-term studies focusing on the effects of climate change on zooplankton communities around the western Antarctic Peninsula and their impact on the marine food web. Such research relies on regular sampling intervals, which must be adjusted based on the availability of support vessels like the Gould. “To me, the loss of the ARSV Laurence M. Gould marks a setback in the scientific study of the Antarctic region,” said Corso. “Antarctica is warming faster than anywhere in the Southern Hemisphere, and there is untold biodiversity in the region that we’re only beginning to understand. By naming this fish after the ship, we hope to honor its scientific contributions while also bringing attention to the need for additional resources to study this unique ecosystem.” Reference: “Akarotaxis gouldae, a new species of Antarctic dragonfish (Notothenioidei: Bathydraconidae) from the western Antarctic Peninsula” by Andrew D. Corso, Thomas Desvignes, Jan R. McDowell, Chi-Hing Christina Cheng, Ellen E. Biesack, Deborah K. Steinberg and Eric J. Hilton, 30 August 2024, Zootaxa.DOI: 10.11646/zootaxa.5501.2.3
AI Unmasks the Ghost Particle: A New Era in Dark Matter Research
Dark matter, crucial yet unseen, shapes the universe through its gravitational pull. Theories suggest it might occasionally interact with itself, detectable indirectly through advanced AI. The Inception model, using deep learning, distinguishes these interactions from similar cosmic activities, providing a clearer picture of dark matter’s characteristics. Credit: SciTechDaily.com Dark matter, making up 85% of all matter in the universe, remains elusive due to its invisible nature, studied only through its gravitational effects. Scientists, using theories of particle interaction and advanced AI algorithms, are peeling back layers of cosmic activity to isolate dark matter’s properties. This effort is bolstered by innovative AI tools like the Inception model, which accurately differentiates between dark matter effects and other cosmic phenomena, potentially revealing dark matter’s true nature as data from new telescopes becomes available. Unraveling Dark Matter’s Mystery Dark matter is the invisible force holding the universe together – or so we think. It makes up around 85% of all matter and around 27% of the universe’s contents, but since we can’t see it directly, we have to study its gravitational effects on galaxies and other cosmic structures. Despite decades of research, the true nature of dark matter remains one of science’s most elusive questions. According to a leading theory, dark matter might be a type of particle that barely interacts with anything else, except through gravity. But some scientists believe these particles could occasionally interact with each other, a phenomenon known as self-interaction. Detecting such interactions would offer crucial clues about dark matter’s properties. However, distinguishing the subtle signs of dark matter self-interactions from other cosmic effects, like those caused by active galactic nuclei (AGN) – the supermassive black holes at the centers of galaxies – has been a major challenge. AGN feedback can push matter around in ways that are similar to the effects of dark matter, making it difficult to tell the two apart. AI Innovations in Astronomy In a significant step forward, astronomer David Harvey at EPFL’s Laboratory of Astrophysics has developed a deep-learning algorithm that can untangle these complex signals. Their AI-based method is designed to differentiate between the effects of dark matter self-interactions and those of AGN feedback by analyzing images of galaxy clusters – vast collections of galaxies bound together by gravity. The innovation promises to greatly enhance the precision of dark matter studies. Harvey trained a Convolutional Neural Network (CNN) – a type of AI that is particularly good at recognizing patterns in images – with images from the BAHAMAS-SIDM project, which models galaxy clusters under different dark matter and AGN feedback scenarios. By being fed thousands of simulated galaxy cluster images, the CNN learned to distinguish between the signals caused by dark matter self-interactions and those caused by AGN feedback. Results and Implications Among the various CNN architectures tested, the most complex – dubbed “Inception” – proved to also be the most accurate. The AI was trained on two primary dark matter scenarios, featuring different levels of self-interaction, and validated on additional models, including a more complex, velocity-dependent dark matter model. Inception achieved an impressive accuracy of 80% under ideal conditions, effectively identifying whether galaxy clusters were influenced by self-interacting dark matter or AGN feedback. It maintained is high performance even when the researchers introduced realistic observational noise that mimics the kind of data we expect from future telescopes like Euclid. Future of Dark Matter Research What this means is that Inception – and the AI approach more generally – could prove incredibly useful for analyzing the massive amounts of data we collect from space. Moreover, the AI’s ability to handle unseen data indicates that it’s adaptable and reliable, making it a promising tool for future dark matter research. AI-based approaches like Inception could significantly impact our understanding of what dark matter actually is. As new telescopes gather unprecedented amounts of data, this method will help scientists sift through it quickly and accurately, potentially revealing the true nature of dark matter. Reference: “A deep-learning algorithm to disentangle self-interacting dark matter and AGN feedback models” by D. Harvey, 6 September 2024, Nature Astronomy.DOI: 10.1038/s41550-024-02322-8
