SPACE/COSMOS
Engineer aims to make giant leap for welding materials on the moon
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Dr. Wei Li received a grant from NASA to develop a platform that could overcome some of the challenges in building permanent structures in harsh, thin-atmosphere and low-gravity environments.
view moreCredit: The University of Texas
Before humans can colonize the moon or Mars, scientists and engineers must first develop techniques for building permanent structures and pressurized habitats in harsh, thin-atmosphere and low-gravity environments.
Dr. Wei Li, an assistant professor of mechanical engineering in the Erik Jonsson School of Engineering and Computer Science at The University of Texas at Dallas, is developing a virtual lunar welding platform to troubleshoot assembling large structures in such conditions.
“As we try to return to the moon and reach Mars, keeping astronauts safe while achieving the missions is very important,” said Dr. Edward White, professor and department head of mechanical engineering and holder of a Jonsson School Chair. “Being in Earth’s orbit is a lot easier knowing that when things go wrong, we can make repairs and return safely. I’m really excited that Dr. Li’s research will help play an important role in making space travel safer and will enable us to successfully complete space missions.”
Li recently received an Early Stage Innovations three-year grant from NASA for up to $750,000 to support his study of welding on the surface of the moon. He was one of six researchers nationwide selected to receive the 2024 annual award, which is designed to accelerate the development of groundbreaking, high-risk/high-payoff space technologies.
“There are three main challenges for the astronauts working on the moon’s surface,” Li said. “The moon has a very thin atmosphere, so there are steep temperature changes, from around minus 387 degrees Fahrenheit to 260 degrees Fahrenheit. There is also an extreme vacuum environment due to the thin atmosphere. Finally, the gravity on the moon’s surface is only about one-sixth that of the Earth. The extreme environment can complicate the reliable implementation of building or manufacturing large structures on the moon’s surface and can lead to manufacturing defects.”
Welding metal in such an environment can cause defects that impact the material’s load-bearing capability, leading to fractures and ductile cracks; nevertheless, in-space assembly is vital to NASA’s long-term exploration goals, Li said.
“It would be very hard to establish regular machine shops on the moon’s surface to manufacture metal structures as we do on Earth,” Li said. “However, it could be possible to use spacecraft to ship metal components from the Earth to the moon, then deploy welding technology there to assemble the components into large structures that could enable the establishment of a human community.”
Li’s project will simulate lunar conditions to test the processes of electrical arc, laser and electron-beam welding in that type of environment. His virtual lunar welding platform simulates the welding process and welding-joint mechanical properties with a multiple-physics modeling approach. Among the equipment he is using is a custom-built, directed energy deposition machine, a technology typically used for additive manufacturing of metals. Li said the research also could be applied to fused deposition modeling, a type of 3D-printing process that can print nonmetallic parts in space.
Li, who directs the Comprehensive Advanced Manufacturing Lab in the Jonsson School, will work with his team to create the simulated environment at UT Dallas while working directly with NASA researchers, including Dr. Fredrick Michael from NASA’s Marshall Space Flight Center.
Li said his team will validate the simulation framework and modeling results with both space-based and on-the-ground experiments, as well as with historical experimental flight data from Skylab, the first U.S. space station. He said the model could be developed further for other space environments, including Mars and the International Space Station.
'Hidden galaxies' could be smoking gun in universe riddle
Royal Astronomical Society
image:
The final SPIRE Dark Field image map created by combining the Blue (250 micrometres), Green (350 micrometres) and Red (500 micrometres) SPIRE camera channels together, each channel stacking a total of 141 individual images on top of each other. The blobs on the image are all individual galaxies or groups of galaxies. However, the image is so crowded that there is almost no empty space with the faintest galaxies merging into the background light in the map.
view moreCredit: Chris Pearson et al.
Astronomers have peered back in time to find what looks like a population of 'hidden' galaxies that could hold the key to unlocking some of the universe's secrets.
If their existence is confirmed it would "effectively break current models of galaxy numbers and evolution".
The possible galaxies may also provide the missing piece of the puzzle for the energy generation in the universe in infrared light.
That's because their combined light would be enough to top-up the energy budget of the universe to the maximum we observe, effectively accounting for all remaining energy emission at these long wavelengths.
Possible evidence of the galaxies' existence was detected on the deepest ever image of the universe at long far-infrared wavelengths, which features almost 2,000 distant galaxies and was created by a team of researchers led by STFC RAL Space and Imperial College London.
Dr Chris Pearson, from STFC RAL Space, is lead author on one of two papers published today in Monthly Notices of the Royal Astronomical Society.
He said: "This work has pushed the science with Herschel to its absolute limit, probing far below what we can normally discernibly see and potentially revealing a completely new population of galaxies that are contributing to the very faintest light we can observe in the universe."
The team behind the research created their deep view of the universe by stacking 141 images on top of each other using data from the SPIRE instrument on the Herschel Space Observatory, a European Space Agency mission which ran from 2009 to 2013.
The resulting Herschel-SPIRE Dark Field is the deepest ever image of the far-infrared sky – five times deeper than the previous single deepest Herschel observation and at least twice as deep as any other area on the sky observed by the telescope.
Placing the images on top of each other allowed astronomers to see the dustiest galaxies, where most new stars are formed in the cosmos.
It also enabled them to track how the number of galaxies changes with brightness and to measure the contribution each one makes to the total energy budget of the universe.
However, the image was so deep and detected so many galaxies that the individual objects began to merge and become indistinguishable from each other.
This made extracting information challenging, according to Thomas Varnish, a PhD student at the Massachusetts Institute of Technology (MIT) and lead author on the second paper.
"We employed statistical techniques to get around this overcrowding, analysing the blurriest parts of the image to probe and model the underlying distribution of galaxies not individually discernible in the original image," said Mr Varnish, who carried out most of his research as a summer intern at Imperial College London and RAL Space.
"What we found was possible evidence of a completely new, undiscovered population of faint galaxies hidden in the blur of the image, too faint to be detected by conventional methods in the original analysis.
"If confirmed, this new population would effectively break all of our current models of galaxy numbers and evolution."
The researchers are now hoping to confirm the existence of the potential new group of galaxies using telescopes at other wavelengths.
Their aim is to decipher the nature of these faint, dusty objects and their importance in the grand scheme of the evolution of our universe.
Dr Pearson said: "When we look at starlight through normal telescopes, we are only able to read half of the story of our universe, the other half is hidden, obscured by the intervening dust.
"In fact, roughly half of the energy output of the universe is from starlight that has been absorbed by dust and re-emitted as cooler infrared radiation. To fully understand the evolution of our universe we need to observe the sky in both optical and longer wavelength infrared light."
The Herschel Space Observatory was tasked with observing the universe in the infrared, with its SPIRE instrument covering the very longest wavelengths.
Like any scientific instrument in space, the SPIRE instrument also required regular observations for calibration and routinely stared at a single patch of 'dark sky' every month or so, over the duration of its four-year mission.
Herschel held the record for the largest ever infrared space telescope, until it was eclipsed by the James Webb Space Telescope in 2021.
Imperial College London astrophysicist Dr David Clements, who was also involved in the research, added: "These results show just how valuable the Herschel archive is.
"We're still getting great new results more than 10 years after the satellite stopped operating.
"What we can't get, though, is more data at these wavelengths to follow up these fascinating new results. For that we need the next generation far-IR mission, PRIMA, currently being proposed to NASA."
The Probe far-Infrared Mission for Astrophysics (PRIMA) is being supported by a UK consortium including RAL Space, the University of Sussex, Imperial College London and Cardiff University.
It would involve the use of a 1.8-metre telescope optimised for far-infrared imaging and spectroscopy, bridging the gap between existing observatories such as the James Webb Space Telescope and radio telescopes.
PRIMA is one of two proposals shortlisted for NASA's next $1 billion (£772 million) probe mission. The US space agency will confirm its final mission selection in 2026.
ENDS
Video, images and captions
Caption: The final SPIRE Dark Field image map created by combining the Blue (250 micrometres), Green (350 micrometres) and Red (500 micrometres) SPIRE camera channels together, each channel stacking a total of 141 individual images on top of each other. The blobs on the image are all individual galaxies or groups of galaxies. However, the image is so crowded that there is almost no empty space with the faintest galaxies merging into the background light in the map.
Credit: Chris Pearson et al.
Caption: The SPIRE Dark Field observed at different wavelengths (colours) moving from the shortest to the longest infrared wavelengths. The shorter wavelength images are from the Spitzer space telescope using the IRAC camera at 3.5 and 8 micrometres and the MIPS camera at 24 micrometres. These wavelengths are between 10-100 times short than the SPIRE observations and therefore appear sharper (higher resolution). The SPIRE images at 250, 250, 500 micrometres (and the final 250 + 350 + 500 combined RGB image) appear blurrier due to the lower resolution at the wavelengths, highlighting the challenges in identifying individual galaxies in the SPIRE maps. The green cross hair marks the same galaxy for reference in each of the images emphasising how different the sky looks at different wavelengths.
Credit: Chris Pearson et al. (Herschel), Krick et al. 2009 (Spitzer)
Further information
About SPIRE
The SPIRE instrument on Herschel was led by the UK with contributions from an international consortium.
The paper 'The Herschel-SPIRE Dark Field I' by Pearson et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staf335
The paper 'The Herschel-SPIRE Dark Field II' by Varnish et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staf318
For an advance copy of the papers, please email press@ras.ac.uk
Notes for editors
About the Royal Astronomical Society
The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.
The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.
The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.
Keep up with the RAS on Instagram, Bluesky, LinkedIn, Facebook and YouTube.
Download the RAS Supermassive podcast
About the Science and Technology Facilities Council (STFC)
The Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI), is the UK's largest public funder of research into particle and nuclear physics, astronomy and astrophysics, and space science. We operate five national laboratories across the UK which, supported by a network of additional research facilities, increase our understanding of the world around us and develop innovative technologies in response to pressing scientific and societal issues. We also facilitate UK involvement in a number of international research activities including CERN, the James Webb Space Telescope and the Square Kilometre Array Observatory.
Journal
Monthly Notices of the Royal Astronomical Society
Method of Research
Observational study
Article Title
The Herschel-SPIRE Dark Field I and The Herschel-SPIRE Dark Field II
Article Publication Date
10-Apr-2025
SwRI scientists source solar emissions with largest-ever concentration of rare helium isotope
The magnetic field strength in the region was weak, supporting earlier theories
Southwest Research Institute
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SwRI scientists located the source of highest-ever concentration of a rare helium isotope emitted by the Sun. In this Solar Dynamics Observatory extreme ultraviolet image, the blue arrow marks a small bright point located at the edge of a coronal hole (outlined in red) that was the source of the phenomenon.
view moreCredit: NASA/SDO/AIA
SAN ANTONIO — April 9, 2025 —The NASA/ESA Solar Orbiter recently recorded the highest-ever concentration of a rare helium isotope (3He) emitted from the Sun. A Southwest Research Institute-led team of scientists sought the source of this unusual occurrence to better understand the mechanisms that drive solar energetic particles (SEPs) that permeate our solar system. SEPs are high-energy, accelerated particles including protons, electrons and heavy ions associated with solar events like flares and coronal mass ejections.
“This rare isotope, which is lighter than the more common 4He by just one neutron, is scarce in our solar system — found at a ratio of about one 3He ion per 2,500 4He ions,” said SwRI’s Dr. Radoslav Bucik, lead author of a paper describing this phenomenon. “However, solar jets appear to preferentially accelerate 3He to high speeds or energies, likely due to its unique charge-to-mass ratio.”
Bucik said the mechanism behind this acceleration remains unknown, but it can typically boost 3He abundance by up to 10,000 times its usual concentration in the Sun’s atmosphere — an effect unparalleled in any other known astrophysical setting. Incredibly, in this case Solar Orbiter recorded a 200,000-fold enhancement of 3He. In addition to its great abundance, the 3He was accelerated to significantly higher speeds than heavier elements.
The SwRI team pinpointed the origin of the 3He emissions. NASA’s Solar Dynamics Observatory (SDO) provided high-resolution images of a small solar jet at the edge of a coronal hole — a region where magnetic field lines open into interplanetary space. Despite its tiny size, the jet was clearly linked to the SEP event, Bucik said.
“Surprisingly, the magnetic field strength in this region was weak, more typical of quiet solar areas rather than active regions,” he added. “This finding supports earlier theories suggesting that 3He enrichment is more likely in weakly magnetized plasma, where turbulence is minimal.”
Additionally, this event stands out as one of the rare cases where ion enhancements do not follow the usual pattern. Typically, events like these exhibit greater abundance of heavy ions such as iron. But in this case, iron was not increased. Instead, carbon, nitrogen, silicon and sulfur were significantly more abundant than expected. Scientists have observed only 19 similar events in the past 25 years, highlighting the rarity and puzzling nature of this phenomenon.
While the Parker Solar Probe was in a favorable location, it was too far away to detect the event, Bucik notes. This highlights the importance of spacecraft operating closer to the Sun, to detect more of these small, intriguing events and offering valuable insights into the acceleration mechanisms of this least understood energetic particle population in our solar system.
Access this Astrophysical Journal paper, “Origin of unusual composition of 3He-rich solar energetic particles,” at: https://iopscience.iop.org/article/10.3847/1538-4357/adb48d.
For more information, visit https://www.swri.org/markets/earth-space/space-research-technology/space-science/heliophysics.
Journal
The Astrophysical Journal
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Origin of unusual composition of 3He-rich solar energetic particles
Mizzou researcher offers new theory on universe’s star formation
In a new study, University of Missouri astronomy professor Charles Steinhardt challenges the notion long held by professional astronomers that red galaxies are simply "dead" and have ceased forming stars
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Charles Steinhardt
view moreCredit: University of Missouri
The universe doesn’t come with an instruction manual — but if it did, University of Missouri Assistant Professor Charles Steinhardt suspects a few pages are missing. Either the universe has been playing by different rules all along, or humanity has been reading the script wrong.
Traditionally, astronomers have grouped galaxies into two different categories: blue, which are young and actively forming stars, and red, which are older and have ceased star formation. Now, Steinhardt is challenging the traditional understanding of galaxies by proposing a third category: red star-forming. They don’t fit neatly into the usual blue or red — instead, they’re somewhere in between.
“Red star-forming galaxies primarily produce low-mass stars, making them appear red despite ongoing star birth,” he said. “This theory was developed to address inconsistencies with the traditional observed ratios of black hole mass to stellar mass and the differing initial mass functions in blue and red galaxies — two problems not explainable by aging or merging alone. However, what we learned is that most of the stars we see today might have formed under different conditions than we previously believed.”
Steinhardt’s research suggests that red star-forming galaxies might have played a much bigger role in the universe’s history. This could change our current understanding of how galaxies evolve, the processes that shape them and how we measure star formation throughout the universe's history.
“The existence of these galaxies could mean that the universe has formed significantly more stars than previously estimated,” he said. “It supports the idea that the life cycle of galaxies is more complex than a simple progression from blue to red and dead.”
A new take on post-starburst galaxies
Traditionally, galaxies are known to have evolved either through gradual aging or by merging, where the collisions can trigger bursts of new stars. Therefore, astronomers have long been puzzled by post-starburst galaxies, which suddenly stop making new stars after a short period of intense star formation. The common theory is that two galaxies collide, causing a quick burst of new stars before running out of energy and going quiet.
But Steinhardt suggests another possibility. Some of these galaxies may have been slowly forming small, red stars instead of experiencing a sudden burst of star formation. If that’s true, he said, we may need to change how we define post-starburst galaxies, as some might belong to a different category of red star-forming galaxies.
In the future, Steinhardt and his students in Mizzou’s Department of Physics plan on conducting more advanced tests to further investigate star-forming galaxies. Junior Mathieux Harper and a team of undergraduate students will look for more evidence to support the idea that some post-starburst galaxies fall into the newly proposed category. Meanwhile, sophomores Carter Meyerhoff and Zach Borowiak will lead a research project using data from the European Space Agency’s Gaia satellite to study over two billion stars in the Milky Way.
“Do Red Galaxies Form More Stars Than Blue Galaxies?” was published in the Astrophysical Journal.
Journal
The Astrophysical Journal
Article Title
Do Red Galaxies Form More Stars than Blue Galaxies?
Chinese scientists discover drier mantle on Moon's farside, offering potential insight on lunar evolution
Chinese Academy of Sciences Headquarters
image:
Lunar sample return sample missions with associated water content estimates.
view moreCredit: Image by Prof. HU Sen's group
Chinese scientists have discovered that the Moon's mantle contains less water on the lunar farside than on the nearside, based on analysis of basalts collected by the Chang'e-6 (CE6) lunar mission.
This breakthrough research was conducted by a team led by Prof. HU Sen from the Institute of Geology and Geophysics of the Chinese Academy of Sciences. The team's findings, published in Nature, reveal that the mantle source of CE6 mare basalts contains 1–1.5 μg.g⁻¹ of water, indicating that the lunar farside mantle is drier than that of the nearside. This result may offer crucial insight into the Moon's formation and thermochemical evolution.
Over the past two decades, extensive studies of lunar samples from the nearside have demonstrated a highly heterogeneous distribution of water in the Moon's interior, with concentrations ranging from approximately 1 to 200 μg.g⁻¹.
Notably, the crust exposed at the surface of the Procellarum KREEP Terrane on the lunar nearside has a higher thorium (Th) concentration than the other two primary lunar geochemical provinces: the Feldspathic Highlands and the South Pole–Aitken (SPA) Basin on the lunar farside.
Both Th and water are considered incompatible elements during magmatic processes, meaning they preferentially remain in the melt rather than becoming incorporated into crystallizing minerals. This geochemical behavior suggests that the mantle beneath the SPA Basin, on the lunar farside, may contain a lower abundance of water.
To confirm this hypothesis, the research team focused on analyzing water content and hydrogen isotopes in melt inclusions and apatite within CE6 mare basalts—the first samples returned from the farside SPA Basin.
The team's results indicate that the parent magma of these basalts contain 15–168 μg.g⁻¹ of water. Additionally, the team estimated that the mantle source of the CE6 basalts has a water content of 1–1.5 μg.g⁻¹, significantly lower than that of the nearside mantle.
This disparity points to a potential hemispheric dichotomy in the Moon's internal water distribution, mirroring many of the asymmetrical features observed on the lunar surface.
This new estimate of the lunar farside mantle's water content marks a significant step forward in refining our understanding of the bulk silicate Moon's water inventory. It provides important constraints on the giant-impact hypothesis of the Moon's origin and underscores the role of water in the Moon's long-term evolution.
This study was conducted in collaboration with Nanjing University and supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, and other funding agencies.
Journal
Nature
Hubble Space telescope unveils the first images of ongoing star cluster mergers near the center of dwarf galaxies
A new study reports the first direct observation of merging star clusters in the nuclear region of dwarf galaxies. This detection confirms the feasibility of this formation route for nuclei in dwarf galaxies, which has long been debated. The study was published in Nature science journal, and led by Postdoctoral Researcher Mélina Poulain from the University of Oulu, Finland.
Dwarf galaxies are the most abundant type of galaxies that populate the Universe. Composed of 100 times fewer stars than the Milky Way, or even less, they are the building blocks of more massive galaxies. Thus, understanding their formation is key to comprehend galaxy evolution.
A notable fraction of dwarf galaxies host a compact star cluster at their centers, typically made of hundreds of thousands to hundreds of millions of stars. Known as nuclear star clusters, these are the densest type of stellar systems in the Universe. The formation of such extreme objects has been under debate for several decades. In dwarf galaxies, they are believed to form from the merger of smaller star clusters, called globular clusters, after they migrate to the galaxy center. However, no such merger of globular clusters has been directly observed to confirm the theory, until now.
Witnessing rare features
While studying observations of a large sample of nearly 80 dwarf galaxies from the Hubble Space telescope, which were led by Prof. Francine Marleau at the University of Innsbruck, Austria, a group of ten researchers from the international MATLAS collaboration noticed a handful of galaxies with an unusual looking nuclear star cluster. Some showed a couple of star clusters close together, while others had a feature similar to a faint stream of light attached to the nuclear star cluster.
“We were surprised by the streams of light that were visible near the center of the galaxies, as nothing similar has been observed in the past”, explains Mélina Poulain.
A thorough analysis of the features has shown that they have similar properties to globular clusters already detected in dwarf galaxies. This suggests that the observations witness the growth of the nuclear star cluster by the dramatic cannibalization of globular clusters at the cores of those galaxies.
Observations reproduced in simulations
To confirm the origin of the faint streams of light, ultra-high resolution complementary simulations were implemented to model the merging process. This portion of the work, led by Dr. Rory Smith at the Universidad Técnica Federico Santa MarÃa in Santiago, Chile, set up various mergers between star clusters with differing masses, dynamics, and numbers of clusters involved. Results confirm that the observed light streams are created with two star clusters with significant mass differences merge. The larger the mass ratio, the longer the stream. The process typically lasts a short amount of time, less than 100 million years, and the features produced are visible for even less time, which explains the difficulty of catching such a phenomenon.
The new study is part of Poulain’s research project, funded by the Research Council of Finland. The study was published on 9 April 2025 in the prestigious journal Nature: Reference
Learn more about space physics and astronomy research at the University of Oulu
Journal
Nature
Article Title
Evidence of star cluster migration and merger in dwarf galaxies
Article Publication Date
9-Apr-2025
