SPACE/COSMOS
A ‘dead’ 1800s idea rises again... with clues to the mystery of the universe’s missing antimatter
image:
The model suggests a brief “knot-dominated era,” when these tangled energy fields outweighed everything else, a scenario that could be probed through gravitational-wave signals.
view moreCredit: Muneto Nitta/Hiroshima University
In 1867, Lord Kelvin imagined atoms as knots in the aether.
The idea was soon disproven. Atoms turned out to be something else entirely. But his discarded vision may yet hold the key to why the universe exists.
Now, for the first time, Japanese physicists have shown that knots can arise in a realistic particle physics framework, one that also tackles deep puzzles such as neutrino masses, dark matter, and the strong CP problem. Their findings, in Physical Review Letters, suggest these “cosmic knots” could have formed and briefly dominated in the turbulent newborn universe, collapsing in ways that favored matter over antimatter and leaving behind a unique hum in spacetime that future detectors could listen for—a rarity for a physics mystery that’s notoriously hard to probe.
“This study addresses one of the most fundamental mysteries in physics: why our Universe is made of matter and not antimatter,” said study corresponding author Muneto Nitta, professor (special appointment) at Hiroshima University’s International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2) in Japan.
“This question is important because it touches directly on why stars, galaxies, and we ourselves exist at all.”
The universe’s missing antimatter
The Big Bang should have produced equal amounts of matter and antimatter, each particle destroying its twin until only radiation remained. Yet the universe is overwhelmingly made of matter, with almost no antimatter in sight. Calculations show that everything we see today, from atoms to galaxies, exists because just one extra particle of matter survived for every billion matter–antimatter pairs.
The Standard Model of particle physics, despite its extraordinary success, cannot account for that discrepancy. Its predictions fall many orders of magnitude short. Explaining the origin of that tiny excess of matter, known as baryogenesis, is one of physics’ greatest unsolved puzzles.
Nitta and Minoru Eto of Hiroshima University’s WPI-SKCM2, an institute created to study knotted and chiral phenomena across scales and disciplines, working with Yu Hamada of the Deutsches Elektronen-Synchrotron in Germany, believe they have found an answer hiding in plain sight.
By combining a gauged Baryon Number Minus Lepton Number (B-L) symmetry with the Peccei–Quinn (PQ) symmetry, the team showed that knots could naturally form in the early universe and generate the observed surplus.
Eto is also a professor at Yamagata University, and all three researchers are affiliated with Keio University in Japan.
Ghost particles
These two long-studied extensions of the Standard Model patch some of its most puzzling gaps. The PQ symmetry solves the strong CP problem, the conundrum of why experiments don’t detect the tiny electric dipole moment that theory predicts for the neutron, and in the process, introduces the axion, a leading dark matter candidate. Meanwhile, the B–L symmetry explains why neutrinos, ghostlike particles that can slip through entire planets unnoticed, have mass.
Keeping the PQ symmetry global, rather than gauging it, preserves the delicate axion physics that solves the strong-CP problem. In physics, “gauging” a symmetry means letting it act freely at every point in spacetime. But that local freedom comes at a cost. To preserve consistency, nature must introduce a new force carrier to smooth out the equations. By gauging the B–L symmetry, the researchers not only guaranteed the presence of heavy right-handed neutrinos—required to keep the theory anomaly-free and central to leading baryogenesis models—but also introduced a superconducting behavior that provided the magnetic backbone for possibly some of the universe’s earliest knots.
Writhing cosmic relics
As the universe cooled after the Big Bang, its symmetries fractured through a series of phase transitions and, like ice freezing unevenly, may have left behind thread-like defects called cosmic strings, hypothetical cracks in spacetime that many cosmologists believe may still be out there. Though thinner than a proton, an inch of string could outweigh mountains. As the cosmos expanded, a writhing web of these filaments would have stretched and tangled, carrying imprints of the primordial conditions that once prevailed.
The breaking of the B–L symmetry produced magnetic flux tube strings, while the PQ symmetry gave rise to flux-free superfluid vortices. Their very contrast is what makes them compatible. The B-L flux tube gives the PQ superfluid vortex’s Chern–Simons coupling something to latch on. And in turn, the coupling lets the PQ superfluid vortex pump charge into the B-L flux tube, countering the tension that would normally make the loop snap. The result was a metastable, topologically locked configuration called a knot soliton.
“Nobody had studied these two symmetries at the same time,” Nitta said. “That was kind of lucky for us. Putting them together revealed a stable knot.”
Phantomlike barrier crossings
While radiation lost energy as its waves stretched with spacetime, the knots behaved like matter, fading far more slowly. They soon overtook everything else, ushering in a knot-dominated era when their energy density, not radiation’s, ruled the cosmos. But that reign didn’t last. The knots eventually untangled through quantum tunneling, a phantomlike process in which particles slip through energy barriers as if they weren’t there at all. Their collapse generated heavy right-handed neutrinos, a built-in consequence of the B–L symmetry woven into their structure. These massive ghostly particles then decayed into lighter, more stable forms with a faint bias toward matter over antimatter, giving us the universe we now know.
“Basically, this collapse produces a lot of particles, including the right-handed neutrinos, the scalar bosons, and the gauge boson, like a shower,” study co-author Hamada explains. “Among them, the right-handed neutrinos are special because their decay can naturally generate the imbalance between matter and antimatter. These heavy neutrinos decay into lighter particles, such as electrons and photons, creating a secondary cascade that reheats the universe.”
“In this sense,” he added, “they are the parents of all matter in the universe today, including our own bodies, while the knots can be thought of as our grandparents.”
Tying it together
When the researchers followed the math encoded in their model—how efficiently the knots produced right-handed neutrinos, how massive those neutrinos were, and how hot the cosmos reheated after they decayed—the matter–antimatter imbalance we observe today emerged naturally from the equation. Rearranging the formula and plugging in a realistic mass of 10¹² giga-electronvolts (GeV) for the heavy right-handed neutrinos, and assuming the knots channeled most of their stored energy into creating these particles, the model naturally landed at a reheating temperature of 100 GeV. That temperature coincidentally marks the universe’s final window for making matter. Any colder, and the electroweak reactions that convert a neutrino imbalance into matter would shut down for good.
Reheating to 100 GeV would also have reshaped the universe’s gravitational-wave chorus, tilting it toward higher frequencies. Future observatories such as the Laser Interferometer Space Antenna (LISA) in Europe, Cosmic Explorer in the United States, and the Deci-hertz Interferometer Gravitational-wave Observatory (DECIGO) in Japan could one day listen for that subtle change in tune.
“Cosmic strings are a kind of topological soliton, objects defined by quantities that stay the same no matter how much you twist or stretch them,” Eto said. “That property not only ensures their stability, it also means our result isn’t tied to the model’s specifics. Even though the work is still theoretical, the underlying topology doesn’t change, so we see this as an important step toward future developments.”
While Kelvin originally conjectured knots as the fundamental building blocks of matter, the researchers argued that their findings “provide, for the first time, a realistic particle physics model in which knots may play a crucial role in the origin of matter.”
“The next step is to refine theoretical models and simulations to better predict the formation and decay of these knots, and to connect their signatures with observational signals,” Nitta said. “In particular, upcoming gravitational-wave experiments such as LISA, Cosmic Explorer, and DECIGO will be able to test whether the Universe really passed through a knot-dominated era.”
The researchers hope to unravel whether knots were essential to the origin of matter and, in doing so, tie together a fuller story of the universe’s beginnings.
Caption
3D plots of the numerical solution for the knot solitons
Credit
Muneto Nitta/Hiroshima University
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About the World Premier International Research Center Initiative (WPI)
The WPI program was launched in 2007 by Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) to foster globally visible research centers boasting the highest standards and outstanding research environments. Numbering more than a dozen and operating at institutions throughout the country, these centers are given a high degree of autonomy, allowing them to engage in innovative modes of management and research. The program is administered by the Japan Society for the Promotion of Science (JSPS).
See the latest research news from the centers at the WPI News Portal: https://www.eurekalert.org/newsportal/WPI
Main WPI program site: www.jsps.go.jp/english/e-toplevel
About the International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM²) Hiroshima University
While introducing a new research paradigm of “knotted chiral meta matter,” WPI-SKCM² aspires to create artificial materials by design to help address challenging global problems, like the growing energy demand and climate change. By knotting and knitting physical fields and molecules, much like in the Japanese art form of Mizuhiki, we enable new physical behavior and desirable properties that overcome nature’s limitations, such as enabling thermal superinsulation that could save energy for heating and cooling buildings. Recreating natural phenomena in experimentally accessible systems leads to insights into the fundamental laws of nature at scales from its smallest building blocks to the entire Universe. Learn more: https://wpi-skcm2.hiroshima-u.ac.jp/
Neutrino experiments in US and Japan join forces
Caltech researchers co-lead new study refining what we know about the ghostly particles
California Institute of Technology
image:
A picture of the NOvA "far detector" located in Minnesota. Neutrinos sent from Fermilab's NuMI (Neutrinos at the Main Injector) beam travel 810 kilometers underground to reach this detector.
view moreCredit: Reidar Hahn/Fermilab
Very early on in our universe, when it was a seething hot cauldron of energy, particles made of matter and antimatter bubbled into existence in equal proportions. For example, negatively charged electrons were created in the same numbers as their antimatter siblings, positively charged positrons. When the two particles combined, they canceled each other out.
Billions of years later, our world is dominated by matter. Somehow matter "won out" over antimatter, but scientists still do not know how. Now, two of the largest experiments attempting to find answers—projects that focus on subatomic particles called neutrinos—have joined forces.
In a new Nature study, an international collaboration representing the experiments—NOvA in the United States and T2K in Japan—present some of the most precise neutrino measurements in the field. The two teams decided to combine their data to learn more than any one experiment alone could.
"By bringing these two efforts together, we can tease out new insights into how neutrinos work," says Ryan Patterson (BS '00), professor of physics at Caltech, who co-led the NOvA side of the study.
A goal of both projects is to determine whether regular neutrinos and antineutrinos (their antimatter counterparts) behave in ways that are asymmetrical relative to each other. This asymmetry could explain why matter was favored over antimatter in the early universe. The new results do not yet indicate whether this is the case, but the exquisite measurements bring scientists closer to understanding the mystery.
"Neutrino physics is a strange field. It is very challenging to isolate effects,” says Kendall Mahn, a professor at Michigan State University and the co-spokesperson for T2K.
Both experiments are known as "long baseline," which means they send neutrinos traveling through Earth's crust for hundreds of kilometers. NOvA, the NuMI Off-axis νe Appearance experiment, sends a beam of neutrinos 810 kilometers from its source at the U.S. Department of Energy’s Fermi National Accelerator Laboratory (Fermilab) near Chicago to a 14,000-ton neutrino detector in Ash River, Minnesota.
The T2K experiment’s neutrino beam travels 295 kilometers west from the city of Tokai in central Japan to Kamioka—hence the name T2K. Tokai is home to the Japan Proton Accelerator Research Complex (J-PARC) and Kamioka hosts the Super-Kamiokande neutrino detector, an enormous tank of ultrapure water located a kilometer underground. In 1998, Super-Kamiokande discovered that neutrinos have mass, a landmark finding that later earned two of its discoverers the 2015 Nobel Prize in Physics.
But while neutrinos have mass, they are extremely lightweight and often referred to as ghostly for their ability to travel unhindered through substances like the ground beneath us. They come in three flavors: the electron neutrino, muon neutrino, and tau neutrino. As neutrinos travel through space or in the ground, they can switch flavors. If you think of the flavors as being like strawberry, chocolate, and vanilla, this would be like finding your strawberry ice cream cone turned to chocolate on your way home.
The phenomenon, called neutrino oscillation, has to do with the fact that each flavor is a quantum superposition of three different mass "states," each with its own distinct mass. As the neutrinos travel, the relative proportions of each of those three mass states will shift, which changes their flavor. The big question for neutrino scientists is whether regular neutrinos and antineutrinos change flavors in different, asymmetric ways. If they do, this would help solve the missing antimatter problem.
To study neutrino oscillation, the researchers produce neutrinos or antineutrinos of a specific flavor at the source of the experiments and then measure what flavors arrive at the detectors. In the case of NOvA, for example, this means sending the particles from Fermilab to the detector in Minnesota.
"As our neutrinos travel through Earth's crust, they pick up another sort of asymmetry en route in addition to the possible intrinsic asymmetry in the particles themselves. It is this intrinsic asymmetry that may help explain the lack of antimatter in our universe," Patterson says. "Both effects teach us new things about neutrinos but separating them is key."
One tricky aspect of studying neutrino oscillation is that scientists do not know the actual masses of the three mass states making up each flavor of neutrino. It is like knowing strawberry, chocolate, and vanilla ice cream are made of three unique ingredients in different proportions but not knowing how heavy the ingredients are. Scientists are actively trying to figure out the relative ordering of the three mass states. In the case of our three ice cream ingredients, this is like asking how their masses compare to each other. There are two possible ordering schemes. Under so-called normal ordering, two of the mass states are relatively light and one is heavy, while an inverted ordering has two heavier mass states and one light.
"Resolving the ordering question is another central goal in the field," Patterson explains. "It connects to a wide array of phenomena from the subatomic to the cosmological scale."
The combined results of NOvA and T2K so far do not favor one mass ordering scenario over another. However, if future results show the neutrino mass ordering is inverted and not normal, NOvA’s and T2K’s results published today provide evidence that neutrinos do exhibit the suspected asymmetry, potentially explaining why the universe is dominated by matter instead of antimatter.
In the future, the scientists will analyze more data from NOvA and T2K, as well as data acquired by planned neutrino experiments that, when operational in the early 2030s, will provide even more precise measurements. Caltech scientists, led by Patterson, are helping to develop the Fermilab-based Deep Underground Neutrino Experiment (DUNE) under construction in Illinois and South Dakota. With its longer baseline of 1,300 kilometers, DUNE will be more sensitive to the neutrino mass ordering than NOvA and T2K, and it could give physicists a conclusive answer shortly after it turns on. Japan is also building a new neutrino experiment, Hyper-Kamiokande, a sequel to Super-Kamiokande, and China is building an experiment called the Jiangmen Underground Neutrino Observatory.
The Nature study is titled "Joint neutrino oscillation analysis from the T2K and NOvA experiments." Caltech's work in the study was funded by the U.S. Department of Energy. Other Caltech-affiliated scientists contributing to the study include senior research scientist Leon Mualem; Varun Raj (PhD '25); former postdoc Kathryn Sutton; and former postdoc Zoya Vallari, now an assistant professor of physics at Ohio State University.
Another view of the NOvA far detector in Minnesota. The detector comprises 344,000 individual cells each 50 feet long and filled with a mixture of mineral oil and dissolved light-emitting chemicals. When a neutrino interacts in the detector, it produces a spray of high-energy particles that stream through the cells and light them up. Researchers detect and analyze that light to study how the neutrinos have changed over their journey from Fermilab.
Credit
Reidar Hahn/Fermilab
A picture of a neutrino detection. Here, a neutrino entered from the left and interacted to produce a high-energy muon (the long prominent "line"), plus a number of other particles. The presence of the muon reveals that the incoming neutrino was of the corresponding type (muon neutrino). The two panels show the event from a top-down and side view, made possible by having detector cells run in two different directions.
Credit
Caltech
Journal
Nature
Method of Research
Meta-analysis
Subject of Research
Not applicable
Article Title
Joint neutrino oscillation analysis from the T2K and NOvA experiments
Article Publication Date
22-Oct-2025
Chang’e-6 meteorite relics shed light on solar system material migration
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Relics of the impactor identified in the Chang'e-6 lunar regolith.
view moreCredit: Image by Prof. XU Yigang's team.
Meteorites, known as messengers of the Solar System, are critical objects for studying the formation and evolution of planets. However, most meteorites cannot be preserved on Earth due to atmospheric filtration and erosion from active geological processes. This situation is even more severe for fragile Carbonaceous Ivuna-type (CI) chondrites, which account for less than 1% of Earth's meteorite collection. In contrast, the Moon serves as a "natural archive" for meteorites, benefiting from its barely-there atmosphere and almost inactive geological processes.
Recently, a research team led by Prof. XU Yigang and Prof. LIN Mang from the Guangzhou Institute of Geochemistry of the Chinese Academy of Sciences identified seven olivine-bearing clasts from two grams of lunar regolith returned by the Chang'e-6 mission. Their findings were published in Proceedings of the National Academy of Sciences (PNAS) on Oct. 20.
Further analysis of the trace-element and oxygen-isotope compositions of the olivine clasts confirmed that they are relics of CI-like chondrites. The researchers noted that these relics formed through the rapid-cooling-induced crystallization of melt droplets, which were generated when CI chondrites melted upon hitting the lunar surface. This study also established an integrated method for identifying meteoritic materials in extraterrestrial samples.
The parent bodies of CI chondrites were originally formed in the outer Solar System, and some of them migrated into the inner Solar System during the formation of planets. This discovery confirms that this kind of material have finally migrated into the Earth-Moon System. A preliminary statistical analysis of meteoritic materials on the Moon shows that the proportion of CI chondrites on the Moon is significantly higher than in Earth's meteorite collection—indicating that the contribution of CI chondrites to the Earth-Moon system has been severely underestimated.
Furthermore, CI chondrites are rich in water and organic materials, so this discovery also has important implications for understanding the origin of water on the lunar surface. Additionally, the researchers suggested that the previously detected water with a positive δ18O and Δ17O signatures in lunar samples was likely the result of the impact of such meteorites.
This study not only reshapes our understanding of how materials migrate through the Solar System but also provides new directions for future research on the origin and distribution of lunar water resources.
Journal
Proceedings of the National Academy of Sciences
Planetary scientists link Jupiter’s birth to Earth’s formation zone
Gas giant’s early growth carved rings that created primitive meteorites, set architecture for inner solar system
image:
Diagram of Jupiter's growth.
view moreCredit: Rice University.
New research from Rice University suggests that the giant planet Jupiter reshaped the early solar system in dramatic ways, carving out rings and gaps that ultimately explain one of the longest-standing puzzles in planetary science: why many primitive meteorites formed millions of years after the first solid bodies. The study, which combined hydrodynamic models of Jupiter’s growth with simulations of dust evolution and planet formation, was recently published in Science Advances.
Through state-of-the-art computer simulations, planetary scientists André Izidoro and Baibhav Srivastava found that Jupiter’s rapid early growth destabilized the sun’s surrounding disk of gas and dust. The planet’s immense gravity sent ripples through the newborn solar system’s disk, creating “cosmic traffic jams” that prevented small particles from spiraling into the sun. Instead, these particles collected into dense bands where they could clump together into planetesimals — the rocky seeds of planets.
The surprising twist is that the planetesimals formed in these bands were not the solar system’s original building blocks. Instead, they represent a second generation, born later in the system’s history. Their birth coincides with that of many chondrites — a family of stony meteorites that preserve chemical and chronological clues from the solar system’s infancy.
“Chondrites are like time capsules from the dawn of the solar system,” said Izidoro, assistant professor of Earth, environmental and planetary sciences at Rice. “They have fallen to Earth over billions of years, where scientists collect and study them to unlock clues about our cosmic origins. The mystery has always been: Why did some of these meteorites form so late, 2 to 3 million years after the first solids? Our results show that Jupiter itself created the conditions for their delayed birth.”
Chondrites are especially significant because they are some of the most primitive materials available to science. Unlike meteorites from the first generation of building blocks — which melted, differentiated and lost their original character — chondrites preserve pristine solar system dust and tiny molten droplets called chondrules. Their late formation has puzzled scientists for decades.
“Our model ties together two things that didn’t seem to fit before — the isotopic fingerprints in meteorites, which come in two flavors, and the dynamics of planet formation,” said Srivastava, a graduate student working in Izidoro’s lab. “Jupiter grew early, opened a gap in the gas disk, and that process protected the separation between inner and outer solar system material, preserving their distinct isotopic signatures. It also created new regions where planetesimals could form much later.”
The study also helps explain another solar system mystery: why Earth, Venus and Mars are clustered around 1 astronomical unit from the sun rather than spiraling inward as happens in many extrasolar planetary systems. Jupiter cut off the flow of gas material toward the inner solar system, suppressing the inward migration of young planets. Instead of plunging toward the sun, these growing worlds remained trapped in the terrestrial region, where Earth and its neighbors eventually formed.
“Jupiter didn’t just become the biggest planet — it set the architecture for the whole inner solar system,” Izidoro said. “Without it, we might not have Earth as we know it.”
The findings are consistent with striking ring-and-gap structures astronomers now observe in young star systems with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope, the most complex astronomical observatory ever built on Earth and located in northern Chile.
“Looking at those young disks, we see the beginning of giant planets forming and reshaping their birth environment,” Izidoro said. “Our own solar system was no different. Jupiter’s early growth left a signature we can still read today, locked inside meteorites that fall to Earth.”
This research was supported in part by the National Science Foundation (NSF), the NSF-funded Big-Data Private-Cloud Research Cyberinfrastructure and Rice’s Center for Research Computing.
Journal
Science Advances
Article Title
The late formation of chondrites as a consequence of Jupiter-induced gaps and rings
Article Publication Date
22-Oct-2025
Telescope hack opens a sharper view into the universe
It is the first time the novel imaging technique has been used on telescopes
A novel imaging technique used for the first time on a ground-based telescope has helped a UCLA-led team of astronomers to achieve the sharpest-ever measurement of a star’s surrounding disk, revealing previously unseen structure. The breakthrough opens a new way for astronomers to study fine details of a wide variety of astronomical objects and opens the door to new discoveries about the universe.
The ability to view fine details of astronomical objects depends on the size of the telescope. As a telescope’s viewing aperture gets bigger, it collects more light to reveal fainter objects, and its images can also become sharper. The sharpest details are obtained by linking telescopes together into arrays. Building larger telescopes or linking them into arrays has been critical to obtain the high-resolution images needed to discover new details at the finest scales visible in the sky.
With the new photonic lantern, it is possible to make better use of the light collected by a telescope to achieve a high resolution. Details of the achievement are published in the journal Astrophysical Journal Letters.
“In astronomy, the sharpest image details are usually obtained by linking telescopes together. But we did it with a single telescope by feeding its light into a specially designed optical fiber, called a photonic lantern. This device splits the starlight according to its patterns of fluctuation, keeping subtle details that are otherwise lost. By reassembling the measurements of the outputs, we could reconstruct a very high-resolution image of a disk around a nearby star,” said first author and UCLA doctoral candidate Yoo Jung Kim.
The light collected by the telescope is split by the photonic lantern into multiple channels based on the shape of the wavefront — like separating a chord into its individual musical notes — and then further split by color, like a rainbow. The photonic lantern itself was designed and fabricated by the University of Sydney and the University of Central Florida, and is part of the new instrument FIRST-PL developed and led by the Paris Observatory and the University of Hawai’i. This instrument is integrated on the Subaru Coronagraphic Extreme Adaptive Optics instrument at the Subaru Telescope in Hawai’i, operated by the National Astronomical Observatory of Japan.
“What excites me most is that this instrument blends cutting-edge photonics with the precision engineering done here in Hawai’i,” said Sebastien Vievard, a faculty member in the Space Science and Engineering Initiative at the University of Hawai’i who helped lead the build. “It shows how collaboration across the world, and across disciplines, can literally change the way we see the cosmos.”
The approach, splitting light into its different components, enables a novel imaging technique that can achieve finer resolution than traditional imaging methods.
“For any telescope of a given size, the wave nature of light limits the fineness of the detail that you can observe with traditional imaging cameras. This is called the diffraction limit, and our team has been working to use a photonic lantern to advance what is achievable at this frontier,” said UCLA professor of physics and astronomy Michael Fitzgerald.
“This work demonstrates the potential of photonic technologies to enable new kinds of measurement in astronomy,” said Nemanja Jovanovic, a co-leader of the study at the California Institute of Technology. “We are just getting started. The possibilities are truly exciting.”
During the application of this new method, scientists were, at first, hampered by turbulence in the Earth’s atmosphere. The effect, which is similar to how the horizon sometimes appears wavy or watery on a hot summer day, causes objects viewed through the telescope to fluctuate and wiggle. To correct for these effects, the team at the Subaru Telescope used adaptive optics, which continuously cancel out the turbulence effects to stabilize the light waves in real time. Out of necessity, researchers went one step further, striving for clarity.
“We need a very stable environment to measure and recover spatial information using this fiber,” said Kim. “Even with adaptive optics, the photonic lantern was so sensitive to the wavefront fluctuations that I had to develop a new data processing technique to filter out the remaining atmospheric turbulence.”
The team used the photonic lantern-equipped Subaru Telescope to observe a star called beta Canis Minoris (β CMi). This star, located in the constellation Canis Minor, is about 162 light-years from Earth and has a surrounding disc that consists of hydrogen. The disc rotates so quickly around the star that the gas moving toward us glows bluer, while the gas moving away appears redder. This is due to the Doppler effect, which describes phenomena like the higher pitch of an approaching car and the lower pitch of a receding car. This color shift causes the apparent position of the system’s light to move slightly with wavelength.
By applying new computational techniques, the team measured these color-dependent image shifts with about five times greater precision than was previously possible. Beyond confirming the disc’s rotation, they discovered that the disc is lopsided.
“We were not expecting to detect an asymmetry like this, and it will be a task for the astrophysicists modeling these systems to explain its presence,” said Kim.
The new approach to imaging will allow astronomers and astrophysicists to view details of objects that are smaller and more distant than ever before, unlocking answers to some mysteries, and, as in the case of the lopsided disc around β CMi, lead to new mysteries that need to be solved.
The international effort included researchers from the Space Science and Engineering Initiative group at the University of Hawai’i, the National Astronomical Observatory of Japan, the California Institute of Technology, the University of Arizona, the Astrobiology Center in Japan, the Paris Observatory, the University of Central Florida, the University of Sydney, and the University of California Santa Cruz.
Journal
The Astrophysical Journal Letters
Successful ground-to-satellite laser communications applying next-generation error correction codes, mitigating atmospheric turbulence
image:
Figure1 Experimental Setup of Data Transmission with Next-Generation Error Correction Codes
view moreCredit: National Institute of Information and Communications Technology, Nagoya Institute of Technology, Japan Aerospace Exploration Agency
Abstract
The National Institute of Information and Communications Technology (NICT, President: TOKUDA Hideyuki Ph.D.) and the Nagoya Institute of Technology (NITech, President: OBATA Makoto), collaborated with the Japan Aerospace Exploration Agency (JAXA), have achieved the world’s first successful demonstration of next-generation error correction codes, mitigating the impact of atmospheric turbulence on ground-to-satellite laser communications.
Atmospheric turbulence in ground-to-satellite laser links is known to cause fading, resulting in burst data errors. Error correction codes are one of the key technologies to mitigate such effects. In this experiment, we transmitted next-generation error correction codes with high correction capability (5G NR LDPC and DVB-S2) and successfully corrected burst data errors caused by atmospheric turbulence in the laser link. This result confirmed that both codes can significantly improve communication quality compared to conventional schemes.
This achievement is expected to contribute to the practical implementation of ground-to-satellite laser communications by applying these codes.
Achievements
NICT has been conducting research and development to implement practical ground-to-satellite laser communications. NICT recognizes overcoming atmospheric turbulence as one of technical challenges for the practical implementation. To address this challenge, NICT has carried out ground-to-geostationary (GEO) satellite laser communication experiments using NICT’s 1-meter optical ground station and JAXA’s Laser Utilizing Communication System (LUCAS) onboard the optical data relay satellite, in order to investigate the impact of atmospheric turbulence on communication quality.
This investigation revealed that atmospheric turbulence causes fading lasting from several milliseconds to several tens of milliseconds, which generates burst data errors. These errors lead to degraded and unstable communication quality. Currently, two approaches are available to overcome these effects: optical compensation schemes and error correction codes. Focusing on the advantage of eliminating control systems of optics, NICT adopted error correction codes. We have been working on a plan to demonstrate error correction using next-generation codes with higher correction capability than conventional Reed-Solomon codes, including 5G NR LDPC for 5G applications and DVB-S2 for satellite broadcasting.
In this experiment, NICT, in collaboration with NITech, conducted data transmission with next-generation error correction codes, including 5G NR LDPC and DVB-S2, using a 60 Mbps downlink on the ground-to-GEO satellite laser communication link between NICT’s 1-meter optical ground station and LUCAS. Utilizing NICT’s experiences acquiring atmospheric turbulence, the parameters involved with interleaving method and error correction code were optimized to address burst errors caused by fading.
Analyzing this experimental data successfully demonstrated the correction of burst data errors caused by atmospheric turbulence-induced fading, marking that the world’s first confirmation that 5G NR LDPC and DVB-S2 can significantly improve communication quality compared to conventional codes. These advanced codes not only offer high error correction capability but also are expected to assist practical application in ground-to-satellite laser communications due to achieving easily implementable hardware and potential interoperability with future 5G communication systems.
Future Prospects
This achievement leads to the improvement of communication quality for ground-to-satellite laser links and accelerates their practical implementation. It also enables applying existing terrestrial 5G communication protocols and satellite broadcasting standards to space communication network system. In the future, this technology is expected to play a key role in ground-to-satellite laser communication systems.
This work will be presented on October 28, 2025 (Tuesday), in the International Conference on Space Optical Systems and Applications (ICSOS) 2025, a leading international conference on space optical communication systems.
How a pyrite-oxidizing microbe helps
preserve atmospheric oxygen in sulfate
Research led by Utah geoscientist shows O₂ in sulfate deposits, coupled with geochemical clues, could help identify microbial activity in Earth’s rock record and even in Martian sediments
University of Utah
video:
This video shows the mixing zone on Spain’s Rio Tinto, where green water, rich in the Fe2+ ion of iron, containing very high O₂ content sulfate, is discharging from a mine tailings pile. This water is mixing into the river’s main branch red waters, where most of the iron occurs as Fe3+ and sulfate oxygen is mostly sourced from water. Issaku Kohl narrated the video as he shot it at the historic mining district in Spain that is featured prominently in his research. Scientists consider this contaminated landscape an analog for the surface of Mars.
view moreCredit: Issaku Kohl, University of Utah
Because oxygen-bearing sulfate minerals trap and preserve signals from Earth’s atmosphere, scientists closely study how they form. Sulfates are stable over billions of years, so their oxygen isotopes are seen as a time capsule, reflecting atmospheric conditions while they were evolving on early Earth—and possibly on its planetary neighbor Mars.
A new NASA-funded study led by a University of Utah geochemist examines how sulfate forms when pyrite, commonly known as “fool’s gold,” is oxidized in environments teeming with microbes versus those without them. The researchers focused on Spain’s Rio Tinto, a contaminated river passing through a region where iron and copper were mined for thousands of years. What’s left in the hills of Andalusia may be an environmental calamity, but scientists now regard it as an analog for what the Martian surface may have once been like.
This acidic mine drainage is rich in sulfates and bacteria known to oxidize both sulfur and iron. The research team measured the “triple oxygen isotopes” (ratios of 17O/16O and 18O/16O) in sulfate to figure out how much of the oxygen comes directly from air compared to water.
“This is the first time where we've seen outdoors, not in the lab, that we can perpetuate this direct reaction between O2 and pyrite sulfur if the environmental conditions are just right,” said lead author Issaku Kohl, associate research professor in the Department of Geology & Geophysics. “Because we've been able to identify that niche, we now have geochemical markers or criteria that would allow you to find a similar environment or remnants of a similar environment in the rock record, either on Earth or in an extraterrestrial setting.”
The study homed in on a bacterium called Acidithiobacillus ferrooxidans, believed to be among the earliest clades of microbes, potentially producing energy prior to the evolution of photosynthesis. The research team discovered that in microbe-rich, acidic environments, A. ferrooxidans drives pyrite oxidation in a way that preserves a remarkably high amount, exceeding 80% and up to 90%, of atmospheric oxygen (O₂) in sulfate.
[caption id="attachment_118188" align="alignright" width="647"] Researcher Issaku Kohl recorded this image at a historic mining district in Spain, which scientists now an analog for the surface of Mars. It shows the mixing zone on the Rio Tinto, where green water, rich in the Fe2+ ion of iron, containing very high O₂ content sulfate, is discharging from a mine tailings pile. This water is mixing into the river’s main branch red waters, where most of the iron occurs as Fe3+ and sulfate oxygen is mostly sourced from water.[/caption]
Unlike lab experiments, where this signal fades quickly as sulfate incorporates O₂ from water, the Rio Tinto microbial-active ecosystem maintains this strong atmospheric imprint.
Accordingly, sulfate deposits don’t just preserve atmospheric and environmental conditions—they may also carry a microbial “biosignature.” Such signatures could help scientists interpret sulfate minerals on Mars or in ancient Earth rocks as a potential record of both atmospheric conditions and microbial activity.
Martian sediments hosted evaporites containing abundant sulfate minerals, but scientists don’t yet know how those sulfates formed.
“The current favored hypothesis is that it's through atmospheric oxidation of volcanic sulfur dioxide (SO₂). But environments like that have telltale geochemical signatures that indicate whether this was likely aerosolized and oxidized in the atmosphere at relatively high temperature and therefore, unlikely to have had life involved,” Kohl said.
But that does not discount the possibility that in localized environments, there could have been hyperacidic fluids that were oxidizing at the water-rock interface, the way Kohl’s experiments and Rio Tinto were producing sulfate.
The study outlines an approach for analyzing oxygen isotope data from Martian sediments for signs of life, should samples ever be brought home to Earth. NASA’s Curiosity and Perseverance rovers have been collecting samples since 2021 and 2012, respectively, with the hope of someday bringing them back on future missions to Earth’s red neighbor.
But Kohl emphasized that the science is still two steps away from being able to determine whether rock samples from Mars bear conclusive evidence of past microbial life. First, the samples would have to be indicative of a very low-pH (acidic) environment, O₂-oxidation-dominant environment, rich in a particular ion of iron(2+).
“We can never get away from our assumptions when we're trying to relate rock records to environments that we deal with in real time in the modern era,” Kohl said. “If we make the assumption that we know the amount of atmospheric O2 in sulfate, we can back calculate the isotopic composition of the O₂ that was involved in making those sulfates.”
And while we wait for interplanetary voyages to deliver us Martian rocks, these findings could open new lines of investigation into environmental conditions here on Earth billions of years ago, when microbial life began evolving and oxygen first appeared in the atmosphere.
The paper titled, “Triple-oxygen isotopic evidence of prolonged direct bioleaching of pyrite with O2,” appeared online Sept. 30 in Earth and Planetary Science Letters, which releases it in print on Oct. 24. The research was supported by the NASA Astrobiology Institute. Co-authors include Max Coleman of the Jet Propulsion Laboratory; Bryan Killingsworth of the U.S. Geological Survey; Karen Ziegler, University of New Mexico; and Edward Young, University of California, Los Angeles.
Journal
Earth and Planetary Science Letters
Method of Research
Experimental study
Article Title
Triple-oxygen isotopic evidence of prolonged direct bioleaching of pyrite with O2
Article Publication Date
30-Sep-2025
COI Statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
