SPACE / COSMOS
Protostellar jet detection in Milky Way’s outer region reveals universal star formation
Protostellar jets were detected for the first time using ALMA in the Milky Way’s outer region, showing that star formation works similarly in distant, low-metallicity regions, whereas the chemistry offers rare clues to early cosmic conditions
image:
Protostellar outflows and jets discovered in the outer Galaxy. The left panel shows CO line emission images obtained with ALMA observations. The red and blue contours represent high-velocity jet gas moving away from and toward us, respectively. The grayscale background indicates the distribution of lower-velocity outflow gas. The green star indicates the positions of the protostar. The yellow and green squares indicate the regions observed with ALMA in this study.
view moreCredit: Ikeda et al. (Niigata univ.), background: R. Hurt/NASA/JPL-Caltech/ESO
Astronomers have gained insights into star formation by capturing the first spatially resolved detection of protostellar outflows and jets in the Milky Way’s outer region. The discovery, made using the Atacama Large Millimeter/submillimeter Array (ALMA), revealed that although the fundamental physics of star formation remains the same across different galactic environments, different chemistry or dust composition is observed in the outer Galaxy source.
The research focused on the protostellar source Sh 2-283-1a SMM1, located about 7.9 kiloparsecs (26,000 light-years) from the Sun and 15.7 kiloparsecs (51,000 light-years) from the Galactic center. This outer-Galaxy region contains only about one-third of the heavy elements found near the Sun. Such low-metallicity environments resemble those of the early Milky Way, making the site a rare natural laboratory for understanding star formation process in primitive environments.
ALMA’s observations revealed a striking bipolar system: narrow jets of high-velocity gas streaming away from the protostar, surrounded by broader, slower-moving outflows. This study tracked gas moving toward and away Earth using blue and red contours, respectively. The surrounding outflow appeared in gray, and the protostar itself was marked with a green star. These captured images provided the first clear view of protostellar jets resolved at such a large galactocentric distance.
Analysis of the velocity structure revealed that the jets are episodic rather than continuous. Instead of a steady flow, the protostar undergoes bursts of mass ejection recurring every 900–4,000 years. This stop-and-start rhythm regulates star growth, allowing it to accrete material from its disk while expelling excess mass and angular momentum. Although episodic ejections have been observed in nearby star-forming regions, this study reported such activity in a source more than 15 kiloparsecs from the Galactic center for the first time.
“By resolving jets and outflows in a protostar so far out in the Galaxy, we can see that the same physics shaping stars near the Sun also operates in low-metallicity environments. This discovery unlocks a unique opportunity to fundamentally advance our understanding of how stars are born across diverse cosmic environments,” said lead author Toki Ikeda of Niigata University.
The chemistry of the jets reflects their unusual environment. Measurements of carbon monoxide (CO) and silicon monoxide (SiO) show that the N(SiO)/N(CO) ratio appears lower in the outer-Galaxy protostellar core than in comparable sources in the inner Galaxy. This suggests that shock chemistry or dust properties differ in the outer Galaxy, where heavy elements are scarce. The finding reinforces that the physics of star formation is universal, whereas the chemistry varies depending on the local conditions.
Further analysis classified Sh 2-283-1a SMM1 as a hot core, i.e., a compact, warm, and chemically rich region surrounding a forming star This marks only the second detection of a hot core in the outer Galaxy, highlighting the rarity of such chemically complex regions so far from the Galactic center. The team further estimates the luminosity of protostar at approximately 6,700 times that of the Sun, placing it in the intermediate-to-high–mass category.
“Finding such a clean jet structure in the outer Galaxy was unexpected,” said Takashi Shimonishi, a co-author from Niigata University. “Even more exciting, the protostar was found to harbor complex organic molecules, opening up new opportunities to study star formation in more primitive environments from both physical and chemical perspectives.”
Beyond Sh 2-283-1a SMM1, ALMA also detected molecular outflows from four additional protostars in the outer Galaxy, confirming that star formation in these remote regions is both active and widespread.
These findings have great implications for astrophysics. By resolving jets and outflows from a protostar in a low-metallicity environment, the study confirms that the blueprint for star formation holds across the Milky Way, regardless of chemical composition. Moreover, the distinct chemical signatures of the outflows offer a glimpse into various conditions that shaped the earliest generations of stars.
The breakthrough underscores ALMA’s ability to extend the frontier of star formation studies. Until now, resolved studies of protostellar molecular jets were limited to objects only a few thousand light-years away. By extending this capability to the outer Galaxy, astronomers can now test whether models developed in nearby star-forming regions apply throughout the Galaxy.
Looking ahead, the team plans to expand their survey to additional outer-Galaxy protostars. Broader surveys could reveal whether episodic ejection cycles vary with metallicity, and whether molecules like SiO behave differently across environments. These efforts will build a fuller picture of how stars and planetary systems emerge in the diverse chemical landscapes of the Milky Way.
By capturing the first resolved jets in Sh 2-283-1a SMM1, identifying their episodic nature, and confirming the source as a rare hot core, this study bridges today’s star formation with the processes that shaped the early Universe. It shows that while chemistry changes with environment, the physics of stellar birth is a constant, i.e., linking the Milky Way’s outskirts to the Universe’s ancient past.
Journal
The Astrophysical Journal
Article Title
The detection of spatially resolved protostellar outflows and episodic jets in the outer Galaxy
Wobbling precisely through space
Accurate measurement of the Earth's axial movement without looking at the sky
Technical University of Munich (TUM)
image:
Ring laser at the Geodetic Observatory Wettzell in Bavaria
view moreCredit: Astrid Eckert / TUM
The results of the 250-day experiment were published in the renowned scientific journal Science Advances. Lead author Prof. K. Ulrich Schreiber from the TUM Institute of Engineering for Astronomical and Physical Geodesy emphasizes: "We have made great progress in measuring the Earth. What our ring laser can do is unique worldwide. We are 100 times more accurate than previously possible with gyroscopes or other ring lasers. The precise measurement of the fluctuations helps us better understand and model the Earth system with high accuracy."
The wobbling Earth
In reality, the Earth's axis is not firmly anchored in the sky, as it appears on a globe. Various forces act on it, causing it to wobble to varying degrees. The strongest influence is the Earth's imperfectly round shape; it bulges slightly at the equator compared to the poles. The effect known as precession causes the extension of the Earth’s axis to trace a circle in the sky. Currently, it is aligned precisely with the North Star. But in the future, it will be aligned with other stars before returning to the North Star in a cycle of 26,000 years.
But the gravitational forces of the sun and moon, which sometimes reinforce or weaken each other, also pull on the Earth's axis. This effect, known as nutation, causes small wave movements in the precession circle of the Earth's axis. There is a distinct nutation with a period of 18.6 years, but also many smaller ones with weekly or daily fluctuations. As a result, the axis does not wobble evenly, but with varying degrees of intensity.
Unprecedented precision
The ring laser was able to measure all these effects directly and continuously over 250 days with a level of accuracy previously unheard of for inertial sensors, i.e., sensors that operate independently of external signals. Unlike in the past, this does not require a network of several large radio telescopes (VLBI) on different continents. The ring laser can do all this on its own in a relatively small instrument located in a underground facility in Wettzell. In addition, the temporal resolution of the fluctuations is less than an hour instead of a day – and the results are available immediately, rather than after days or weeks, as is the case with VLBI.
With a further increase in the measurement accuracy and stability of the ring laser by a factor of 10 in the future, it would even be possible to measure the spacetime distortion caused by the Earth's rotation – a direct test of the theory of relativity. This would allow, for example, the Lense-Thirring effect, i.e., the “dragging” of space by the Earth's rotation, to be tested directly at the Earth's surface.
Journal
Science Advances
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Gyroscope Measurements of the Precession and Nutation of the Earth Axis
Article Publication Date
3-Sep-2025
Artificial intelligence helps boost LIGO
New algorithm hushes unwanted noise in LIGO, may lead to more black hole discoveries
LIGO, the Laser Interferometer Gravitational-wave Observatory, has been called the most precise ruler in the world for its ability to measure motions more than 10,000 times smaller than the width of a proton. By making these extremely precise measurements, the US National Science Foundation-funded LIGO, which consists of two facilities—one in Washington and one in Louisiana—can detect undulations in space-time called gravitational waves that roll outward from colliding cosmic bodies such as black holes.
LIGO ushered in the field of gravitational-wave astronomy beginning in 2015 when it made the first-ever direct detection of these ripples, a discovery that subsequently earned three of its founders the Nobel Prize in Physics in 2017. Improvements to LIGO's interferometers mean that it now detects an average of about one black hole merger every three days during its current science run. Together with its partners, the Virgo gravitational-wave detector in Italy and KAGRA in Japan, the observatory has in total detected hundreds of black hole merger candidates, in addition to a handful involving at least one neutron star.
Researchers want to further enhance LIGO's abilities, so that they can detect a larger variety of black-hole mergers, including more massive mergers that might belong to a hypothesized intermediate-mass class bridging the gap between stellar-mass black holes and much larger supermassive black holes residing at the centers of galaxies. The advances would also make it easier for LIGO to find black holes with eccentric, or oblong, orbits, as well as catch mergers earlier in the coalescing process, when the dense bodies spiral in toward one another.
To do this, researchers at Caltech and Gran Sasso Science Institute in Italy teamed up with Google DeepMind to develop a new AI method–called Deep Loop Shaping–that can better hush unwanted noise in LIGO's detectors. To scientists, the term “noise” can refer to any number of pesky background disturbances that interfere with data collection. The noise can be literal noise, as in sound waves, but in the case of LIGO, the term often refers to a very tiny amount of jiggling in the giant mirrors at the heart of LIGO. Too much jiggling can mask gravitational-wave signals.
Now, reporting in Science, the researchers show that their new AI algorithm, though still a proof-of-concept, quieted motions of the LIGO mirrors by 30 to 100 times more than what is possible using traditional noise-reduction methods alone.
"We were already at the forefront of innovation, making the most precise measurements in the world, but with AI, we can boost LIGO's performance to detect bigger black holes," says co-author Rana Adhikari, professor of physics at Caltech. "This technology will help us not only improve LIGO but also to build next-generation, even bigger gravitational-wave detectors."
The approach could also improve technologies that use control systems. "In the future, Deep Loop Shaping could also be applied to many other engineering problems involving vibration suppression, noise cancellation and highly dynamic or unstable systems important in aerospace, robotics, and structural engineering," write study co-authors Brendan Tracey and Jonas Buchli, an engineer and scientist, respectively, at Google DeepMind, in a blog post about the study.
The Stillest Mirrors
Both the Louisiana and Washington LIGO facilities are shaped like enormous "L's," in which each arm of the L contains a vacuum tube that houses advanced laser technology. Within the 4-kilometer-long tubes, lasers bounce back and forth with the aid of giant 40-kilogram suspended mirrors at each end. As gravitational waves reach Earth from space, they distort space-time in such a way that the length of one arm changes relative to the other by infinitesimally small amounts. LIGO's laser system detects these minute, subatomic-length changes to the arms, registering gravitational waves.
But to achieve this level of precision, engineers at LIGO must ensure that background noises are kept at bay. This study looked specifically at unwanted noises, or motions, in LIGO's mirrors that occur when the mirrors shift in orientation from the desired position by very tiny amounts. Although both of the LIGO facilities are relatively far from the coast, one of the strongest sources of these mirror vibrations is ocean waves.
"It's as if the LIGO detectors are sitting at the beach," explains co-author Christopher Wipf, a gravitational-wave interferometer research scientist at Caltech. "Water is sloshing around on Earth, and the ocean waves create these very low-frequency, slow vibrations that both LIGO facilities are severely disturbed by."
The solution to the problem works much like noise-canceling headphones, Wipf explains. "Imagine you are sitting on the beach with noise-canceling headphones. A microphone picks up the ocean sounds, and then a controller sends a signal to your speaker to counteract the wave noise," he says. "This is similar to how we control ocean and other seismic ground-shaking noise at LIGO."
However, as is the case with noise-canceling headphones, there is a price. "If you have ever listened to these headphones in a quiet area, you might hear a faint hiss. The microphone has its own intrinsic noise. This self-inflicted noise is what we want to get rid of in LIGO," Wipf says.
LIGO already handles the problem extremely well using a traditional feedback control system. The controller senses the rumble in the mirrors caused by seismic noise and then counteracts these vibrations, but in a way that introduces a new higher-frequency quiver in the mirrors—like the hiss in the headphones. The controller senses the hiss too and constantly reacts to both types of disturbances to keep the mirrors as still as possible. This type of system is sometimes compared to a waterbed: Trying to quiet waves at one frequency leads to extra jiggling at another frequency. Controllers can automatically sense the disturbances and stabilize a system.
Adhikari wanted to further improve the LIGO control system, in particular to reduce the controller-induced hiss, which interferes with gravitational-wave signals in the lower-frequency portion of the observatory's range. LIGO detects gravitational waves with a frequency between 10 and 5,000 Hertz (humans hear sound waves with a frequency between 20 and 20,000 Hertz). The unwanted hiss lies in the range between 10 and 30 Hertz—and this is where more massive black holes mergers would be picked up, as well as where black holes would be caught near the beginning of their final death spirals (for instance, the famous "chirps" heard by LIGO start in lower frequencies then rise to a higher pitch.)
About four years ago, Jan Harms, a former Caltech research assistant professor who is now a professor at Gran Sasso Science Institute, reached out to experts at Google DeepMind to see if they could help develop an AI method to better control vibrations in LIGO's mirrors. At that point, Adhikari got involved, and the researchers began working with Google DeepMind to try different AI methods. In the end, they used a technique called reinforcement learning, which essentially taught the AI algorithm how to better control the noise.
"This method requires a lot of training," Adhikari says. "We supplied the training data, and Google DeepMind ran the simulations. Basically, they were running dozens of simulated LIGOs in parallel. You can think of the training as playing a game. You get points for reducing the noise and dinged for increasing it. The successful 'players' keep going to try to win the game of LIGO. The result is beautiful—the algorithm works to suppress mirror noise."
Richard Murray (BS ‘85), the Thomas E. and Doris Everhart Professor of Control and Dynamical Systems and Bioengineering at Caltech, explains that without AI, scientists and engineers mathematically model a system they want to control in explicit detail. "But with AI, if you train it on a model of sufficient detail, it can exploit features in the system that you wouldn't have considered using classical methods," he says. An expert in control theory for complex systems, Murray (who is not an author on the current study) develops AI tools for certain control systems, such as those used in self-driving vehicles.
"We think this research will inspire more students to want to work at LIGO and be part of this remarkable innovation," Adhikari says. "We are at the bleeding edge of what's possible in measuring tiny, quantum distances."
So far, the new AI method was tested on LIGO for only an hour to demonstrate that it works. The team is looking forward to conducting longer duration tests and ultimately implementing the method on several LIGO systems. "This is a tool that changes how we think about what ground-based detectors are capable of," Wipf says. "It makes an incredibly challenging problem less daunting."
The Science paper titled "Improving cosmological reach of LIGO using Deep Loop Shaping" was funded in part by the National Science Foundation.
Journal
Science
Article Title
Improving cosmological reach of a gravitational wave observatory using Deep Loop Shaping
Article Publication Date
4-Sep-2025
Faster energetic particles arriving later
Unraveling interplanetary shock acceleration process using observed Inverse Velocity Dispersion (IVD) structure
Science China Press
image:
Commonly seen velocity dispersion feature is marked with blue circles in lower energy range observed by Solar Orbiter, while the onset of inverse velocity particles is indicated with orange triangles in higher energy ranges.
view moreCredit: ©Science China Press
The acceleration and transport of energetic particles during solar eruptions remain central and long-standing challenges in space plasma physics. A widely accepted picture holds that higher-energy particles released during a solar eruption are detected earlier than lower-energy ones, forming a so-called velocity dispersion (VD) pattern in the dynamic spectrum that is commonly observed in solar energetic particle (SEP) events.
Recent measurements by ESA’s Solar Orbiter have revealed cases where this expectation is reversed, with higher-energy particles arriving later than lower-energy ones. This counterintuitive behavior, known as inverse velocity dispersion (IVD), invokes a bunch of studies.
An international research team, led by Professors Jingnan Guo and Yuming Wang and composed of members from the University of Science and Technology of China, Graz University and Kiel University, analyzed 10 SEP events with clear IVD signatures observed by Solar Orbiter’s Energetic Particle Detector (EPD). Rather than focusing on the phenomenon itself, the study investigated the underlying mechanisms. The dominant one is explained within the diffusive shock acceleration (DSA) framework, where particles require progressively longer time to reach higher energies, resulting in energy-dependent release.
Using DSA model, the team went backwards to IVD’s physical origin, innovatively retrieved the parameters of the shock acceleration conditions and determined energy-dependent acceleration timescales under different shock conditions. Observational-derived energy-dependent acceleration time was then used to retrieve the theoretical mean free path of particles at the acceleration shock chose to the Sun.
The findings highlight how IVD structures can serve to derive the physical conditions at interplanetary shocks that cannot be observed directly. By linking observational features with theoretical acceleration models, the study advances our understanding of how shocks energize particles to tens of MeV, a process fundamental to both basic space plasma physics and space weather forecasting.
Beyond its scientific importance, the work also has practical implications. Energetic particles accelerated during solar eruptions pose significant hazards to spacecraft systems and astronaut health. Improved knowledge of the timing and conditions of particle acceleration will help refine models of the radiation environment in the inner heliosphere, supporting future missions to the Moon, Mars, and beyond.
Spaceflight accelerates human stem cell aging, UC San Diego researchers find
Findings reveal space-induced genetic, mitochondrial and inflammatory stress in blood-forming stem cells, offering insight into aging and risk of disease during long-duration space travel
University of California - San Diego
image:
Catriona Jamieson, M.D., Ph.D., discussing the mission to the International Space Station with members of her team
view moreCredit: UC San Diego Health Sciences
Researchers from University of California San Diego Sanford Stem Cell Institute have discovered that spaceflight accelerates the aging of human hematopoietic stem and progenitor cells (HSPCs), which are vital for blood and immune system health. In a study published in Cell Stem Cell, the team used automated artificial intelligence (AI)-driven stem cell-tracking nanobioreactor systems in four SpaceX Commercial Resupply Services missions to the International Space Station (ISS) to track stem cell changes in real time. The findings show that the cells lost some of their ability to make healthy new cells, became more prone to DNA damage and showed signs of faster aging at the ends of their chromosomes after spaceflight — all signs of accelerated aging.
“Space is the ultimate stress test for the human body,” said Catriona Jamieson, M.D., Ph.D., director of the Sanford Stem Cell Institute and professor of medicine at UC San Diego School of Medicine. “These findings are critically important because they show that the stressors of space — like microgravity and cosmic galactic radiation — can accelerate the molecular aging of blood stem cells. Understanding these changes not only informs how we protect astronauts during long-duration missions but also helps us model human aging and diseases like cancer here on Earth. This is essential knowledge as we enter a new era of commercial space travel and research in low earth orbit."
Previous NASA studies have shown that spaceflight can affect immune function and telomere length. One such study — the NASA Twins Study — was a landmark, year-long experiment (2015-2016) where astronaut Scott Kelly spent 340 days aboard the ISS while his identical twin, Mark Kelly, remained on Earth. The study tracked changes across genetics, physiology, cognition and the microbiome and found altered gene expression, shifts in telomere length and changes in the gut microbiome. However, many of these changes reversed or returned to normal after astronaut Kelly returned to Earth. The study did identify some persistent changes, such as increased numbers of short telomeres and disruptions in gene expression, which could be relevant for longer space missions.
This UC San Diego-led study builds on the findings of the Twins Study and the seminal work of the Space Omics and Medical Atlas group which published 44 scientific papers on aerospace medicine and space biology in Nature. By focusing specifically on HSPCs, the study provided a detailed mechanistic look at how space triggers molecular aging, something the Twins Study hinted at but could not fully explore at the cellular level.
To conduct the study, researchers — including Space Tango — developed a novel “nanobioreactor” platform — miniaturized 3D biosensing systems that allowed human stem cells to be cultured in space and monitored with AI-powered imaging tools.
The study’s findings:
- Human HSPCs exposed to 32 to 45 days of spaceflight showed hallmark features of aging. Researchers observed that spaceflight triggers a range of changes in blood-forming stem cells that closely resemble what happens to these cells as we age. The cells became more active than normal, burning through their reserves and losing the ability to rest and recover — a key trait that allows stem cells to regenerate over time.
- Their ability to make healthy new cells declined, while signs of molecular wear-and-tear, like DNA damage and shorter chromosome ends (telomeres), became more pronounced.
- The cells also showed signs of inflammation and stress inside their mitochondria — the cell’s energy producers — and began activating hidden sections of the genome that are normally kept quiet to maintain stability. These stress responses can impair immune function and increase the risk of diseases.
Notably, when these space-exposed cells were later placed in a young, healthy environment, some of the damage began to reverse, suggesting it may be possible to rejuvenate aging cells with the right interventions.
These findings have implications not just for astronaut health, but also for understanding the mechanisms of aging and age-related diseases like cancer on Earth. They underscore the need for new countermeasures to protect stem cell function during extended space missions and support the development of biological markers to detect stress-induced aging early.
“We're excited this breakthrough work is being published to the wider scientific and space communities,” said Twyman Clements, president and co-founder of Space Tango. “Like many accomplishments, this one was a team effort bringing together the Integrated Space Stem Cell Orbital Research Center within SSCI, Space Tango and others. Coupling Space Tango's CubeLab capabilities, specifically the persistent microscopy, has enabled this work and will continue to do so in the future.”
The research team plans to extend this work with additional ISS missions and astronaut-based studies, focusing on real-time monitoring of molecular changes and potential pharmaceutical or genetic countermeasures to protect human health in space and beyond. To date, the SSCI has conducted 17 missions to the ISS.
“Space experiments are so complex that they force you to do better science on the ground,” continued Jamieson. “Space research has accelerated technological advancements on Earth, making ground-based research easier and more relevant to human health. What we have learned about cancer from our studies in space is absolutely remarkable.”
Link to full study.
Additional co-authors on the study include: Jessica Pham, Jane Isquith, Larisa Balaian, Shuvro P. Nandi, Claire Engstrom, Karla Mack, Inge van der Werf, Patrick Chang, Jana Stoudemire, Luisa Ladel, Emma Klacking, Antonio Ruiz, Daisy Chilin-Fuentes, Jenna Sneifer, Alysson R. Muotri, Thomas Whisenant and Ludmil B. Alexandrov from UC San Diego. David Mays, Paul Gamble, Shelby Giza, Jiya Janowitz, Trevor Nienaber and Twyman Clements from Space Tango. Tejaswini Mishra and Michael P. Snyder from Stanford University School of Medicine. Anna A. Khachatrian from Scripps Health. Elsa Molina and Sheldon R. Morris from The Salk Institute for Biological Studies.
The study was funded, in part, by NASA (NRA NNJ13ZBG001N) to UC San Diego Sanford ISSCOR Center; NCI (R01CA205944); NIH/NIDDK (R01DK114468-01); NIH NCI CCSG p30CA023100; NIH NCI CCSG: P30 CA01495; NIH NIA San Diego Nathan Shock Center (P30 AG068635); The Chapman Foundation and the Helmsley Charitable Trust; LLS Blood Cancer Discoveries; Sanford Stem Cell Institute; Koman Family Foundation; JM Foundation and Moores Family Foundation.
# # #
Cat with astronaut helmet
The Sanford Stem Cell Institute has conducted 17 missions to the ISS
Credit
UC San Diego Health Sciences
Journal
Cell Stem Cell
COI Statement
Jamieson is a co-founder of Impact Biomedicines and Aspera Biomedicines and has received royalties from Forty Seven Inc. Morris is a co-founder of Aspera Biomedicines. Mack is an employee of Aspera Biomedicines. Snyder is a co-founder of Personalis, SensOmics, Qbio @qbioinc, January AI, Filtricine, Mirvie, Protos, Protometrix (now part of Thermo-Fisher) and Affomix (now part of Illumina). Muotri is a co-founder and has equity interest in TISMOO. Balaian is a co-founder of IO9. Ladel, Pham, Balaian, Ruiz, Klacking, Whisenant and Jamieson are named on patents related to this work. Other authors declare no competing interests.
