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Skeptics love to bring up one particular topic regarding long-term human space exploration - radiation. So far, all of the research completed on it has been relatively limited and has shown nothing but harmful effects. Long-term exposure has been linked to an increase in cancer, cataracts, or even, in some extreme cases, acute radiation poisoning, an immediate life-threatening condition. NASA is aware of the problem and recently supported a new post-doc from MIT named Robert Hinshaw via the Institute for Advanced Concepts (NIAC) program. Dr. HHinshaw'sjob over the next year will be to study the effectiveness of an extreme type of mitochondria replacement therapy to treat the long- and short-term risks of radiation exposure in space.

The Moon's getting to be a popular place. Firefly's Blue Ghost touched down on March 2nd in Mare Crisium. It's the first privately built lander to land safely and begin its mission. The little spacecraft set down safely in an upright, stable position and sent back an "I'm here" signal right away.

The dividing line between gas giant planets and failed stars is blurry at best. The isolated planetary-mass object SIMP J013656.5+093347.3 could be either one. The distinction is largely semantic. However we choose to label and define it, the object displays a surprisingly complex atmosphere for an isolated object without any stellar energy input.

In an effort to conserve Voyager 2's dwindling energy and extend the spacecraft's mission, NASA has shut down another of its instruments. They did it with the Plasma Spectrometer in October 2024, and it won't be the last. In March, Voyager 2's Low-Energy Charged Particle instrument will be powered down.

There are several well-documented health risks that come from spending extended periods in microgravity, including muscle atrophy, bone density loss, and changes to organ function and health. In addition, astronauts have reported symptoms of immune dysfunction, including skin rashes and other inflammatory conditions. According to a new study, these issues could be due to the extremely sterile environment inside spacecraft and the International Space Station (ISS). Their results suggest that more microbes could help improve human health in space.

The study was led by Rodolfo A. Salido and Haoqi Nina Zhao, a bioengineer and an environmental analytical chemist at the University of California San Diego (UCSD), respectively. They were joined by researchers from multiple UCSD programs and centers, the University of Denver, the Chiba University-UC San Diego Center for Mucosal Immunology Allergy and Vaccines (cMAV), Space Research Within Reach, the Baylor College Center for Space Medicine, the Blue Marble Space Institute of Science (BMSIS), the Biotechnology and Planetary Protection Group at NASA JPL, and the Astronaut Office at NASA Johnson.

The study was a collaborative effort with astronauts aboard the ISS, who swabbed 803 different surfaces – 100 times that of previous surveys – to get a census of microbes aboard the station. The researchers identified which bacterial species and chemicals were present in each sample and created three-dimensional maps to illustrate where each of them was found and how they might be interacting. Their results indicate that the ISS has a much lower diversity of microbes compared to human-built environments on Earth.

NASA astronaut Catherine (Cady) Coleman, Expedition 26 flight engineer, is pictured with a stowage container and its contents in the Harmony node of the International Space Station. Credit: NASA

Overall, the team found that chemicals from cleaning products and disinfectants were ubiquitously throughout the station and that astronauts mostly introduce microbes aboard the ISS through shed human skin cells. They also found that different modules hosted different microbial communities and chemical signatures based on the module’s use. For example, dining and food preparation areas contained more food-related microbes, whereas the ISS’s space toilet contained more urine- and fecal matter-related microbes and bioproducts of metabolism (metabolites).

“We noticed that the abundance of disinfectant on the surface of the International Space Station is highly correlated with the microbiome diversity at different locations on the space station,” said Zhao in a Cell Press release. These results suggest that more microbes from Earth could help improve astronaut health. Said Salido:

“Future built environments, including space stations, could benefit from intentionally fostering diverse microbial communities that better mimic the natural microbial exposures experienced on Earth, rather than relying on highly sanitized spaces. If we really want life to thrive outside Earth, we can’t just take a small branch of the tree of life and launch it into space and hope that it will work out. We need to start thinking about what other beneficial companions we should be sending with these astronauts to help them develop ecosystems that will be sustainable and beneficial for all.” 

The team found that microbial communities were less diverse aboard the ISS than most places on Earth, except where urban, industrialized, and isolated environments (i.e., hospitals) were concerned. They further found that ISS surfaces lacked free-living environmental microbes usually found in soil and water. Similar to the well-documented benefits gardening has for the human immune system, the researchers conclude that incorporating these microbes and their substrates into the ISS could improve astronaut health without sacrificing hygiene.

Astronauts on the International Space Station experience an orbital reboost. Credit: NASA/ESA

“There’s a big difference between exposure to healthy soil from gardening versus stewing in our own filth, which is kind of what happens if we’re in a strictly enclosed environment with no ongoing input of those healthy sources of microbes from the outside,” said co-author Robin Knight, a computational microbiologist and professor at UCSD and leader of the Knight Lab.

Looking to the future, the researchers hope to refine their analyses to detect potentially pathogenic microbes and how environmental metabolites could be used as indicators for astronaut health. The team claims that these methods could also help improve the health of people living and working in similarly sterile environments on Earth.

This research was supported by the National Institute of Health (NIH), the Alfred P. Sloan Foundation, UCSD, the Center for the Advancement of Science in Space (CASIS), and the ISS National Laboratory. The paper detailing their findings, “The International Space Station has a unique and extreme microbial and chemical environment driven by use patterns,” was published on February 27th in the journal Cell.

Further Reading: EurekAlert!

The post For the Sake of Astronaut Health, Should we Make the ISS Dirtier? appeared first on Universe Today.

On December 27th, 2024, the Chilean station of the Asteroid Terrestrial-impact Last Alert System (ATLAS) detected 2024 YR4. This Near-Earth Asteroid (NEA) belongs to the Apollo group, which orbits the Sun with a period of approximately four years. For most of its orbit, 2024 YR4 orbits far from Earth, but sometimes, it crosses Earth’s orbit. The asteroid was spotted shortly after it made a close approach to Earth on Christmas Day 2024 and is now moving away. Additional observations determined it had a 1% probability of hitting Earth when it makes its next close pass in December 2032.

This led the International Asteroid Warning Network (IAWN) – overseen by the United Nations Office for Outer Space Affairs (UNOOSA) – to issue the first-ever official impact risk notification for 2024 YR4. The possibility of an impact also prompted several major telescopes to gather additional data on the asteroid. This included the Subaru Telescope at the Mauna Kea Observatory in Hawaii, which captured images of the asteroid on February 20th, 2025. Thanks to the updated positional data from these observations, astronomers have refined the asteroid’s orbit and determined that it will not hit Earth.

This is not the first time the odds of the asteroid hitting Earth have been reevaluated. Throughout February, refined measurements of the asteroid altered the estimated likelihood multiple times, first to 2.3% and then to 3.1%, before dropping significantly to 0.28%. Thanks to the observations of the Subaru Telescope, which were conducted at the request of the JAXA Planetary Defense Team and in response to the IAWN’s call for improved orbital tracking, the chance of impact has been downgraded to 0.004%.

Monte Carlo modeling of 2024 YR4’s swath of possible locations as of February 23rd, 2025 – 0.004% probability of impact. Credit: iawn.net

The updated estimate was calculated by NASA’s Center for NEO Studies (CNEOS), the ESA’s Near-Earth Objects Coordination Centre (NEOCC), and the NEO Dynamic Site (NEODyS). The Subaru observations were conducted using the telescope’s Hyper Suprime-Cam (HSC), a wide-field prime-focus camera that captured images of 2024 YR4 as it grew dimmer. The observations have since been forwarded to the Minor Planet Center (MPC) of the International Astronomical Union (IAU). Dr. Tsuyoshi Terai of the National Astronomical Observatory of Japan (NAOJ), who led the observations, explained:

“Although 2024 YR4 appeared relatively bright at the time of its discovery, it has been steadily fading as it moves away from the Earth. By late February, observations would have been extremely challenging without a large telescope. This mission was successfully accomplished thanks to the Subaru Telescope’s powerful light-gathering capability and HSC’s high imaging performance.”

Based on these latest observations, the IAWN reports that 2020 YR4 will “pass at a distance beyond the geosynchronous satellites and possibly beyond the Moon.” They also indicate that there is no significant potential that the asteroid will impact Earth in the next century. The IAWN also states that it will continue to track 2024 YR4 through early April. At this point, it will be too faint to image and won’t be observable from Earth again until 2028.

Further Reading: NAOJ

The post Good News! The Subaru Telescope Confirms that Asteroid 2024 YR4 Will Not Hit Earth. appeared first on Universe Today.

There are several well-documented health risks that come from spending extended periods in microgravity, including muscle atrophy, bone density loss, and changes to organ function and health. In addition, astronauts have reported symptoms of immune dysfunction, including skin rashes and other inflammatory conditions. According to a new study, these issues could be due to the extremely sterile environment inside spacecraft and the International Space Station (ISS). Their results suggest that more microbes could help improve human health in space.

On December 3rd, 2018, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) successfully rendezvoused with the Near-Earth Asteroid (NEA) 101955 Bennu. Over the next two years, the mission collected rock and regolith samples from the asteroid’s surface. By September 24th, 2023, the mission’s sample return capsule (SRC) entered Earth’s atmosphere and was collected by NASA scientists. Analysis of these samples is already providing insight into what conditions were like during the early Solar System.

According to a recent study, the known trajectory and timing of the SRC’s return provided a rare opportunity to record geophysical signals produced by the capsule using a new method. Because it was traveling at hypersonic speeds as it flew through the atmosphere, the SRC’s return produced a sonic boom that impacted the ground. Using distributed acoustic sensing (DAS) interrogators and surface-draped fiber-optic cables, the team carried out the first reported recording of an SRC reentry with distributed fiber-optic sensing technology.

The team was led by Dr. Carly M. Donahue and consisted of her colleagues from the Earth and Environmental Sciences Division at the Los Alamos National Laboratory (LANL), as well as the Department of Geosciences at Colorado State University and fiber optic-based distributed sensor developer Silixa LLC. The paper that details their findings, “Detection of a Space Capsule Entering Earth’s Atmosphere with Distributed Acoustic Sensing (DAS),” recently appeared in the journal Seismological Research Letters.

The sample return capsule from the OSIRIS-REx mission is seen shortly after touching down in the Utah desert on September 24th, 2023. Credit: NASA/Keegan Barber

Since the end of the Apollo Era, scientists have studied sample return capsules re-entering Earth’s atmosphere. These studies have helped scientists develop safe and effective methods for sample-return missions and provided insight into the atmospheric entry of meteoroids and asteroids. Until now, these studies employed infrasound and seismic sensors to record the resulting geophysical signals. However, Dr. Donahue and her team saw an opportunity since the trajectory and timing of the OSIRIS-REx mission’s SRC were known in advance.

As Dr. Donahue told Universe Today via email, the reentry was a chance for them to test DAS systems with fiber optic cables to record the geophysical effects produced by the sonic boom. “DAS systems interrogating an optical fiber are still relatively rare,” she said. “Knowing ahead of time the precise trajectory gave us the scarce opportunity to situate multiple DAS interrogators near the point of highest heating and capture the sonic boom as it impacted the ground.”

The team rapidly deployed two DAS interrogators and more than 12 km (7.45 mi) of surface-draped fiber-optic cables. Their network included six collocated seismometer-infrasound sensor pairs, all spread across two sites near the town of Eureka in the Nevada Desert. As Dr. Donahue described:

“Once the team got the hang of rolling out the 4 spools of optical fiber that each weighed over 100 kgs, installing and retrieving the fiber took less time than setting up the six co-located seismic and infrasound stations. Approximately 5 km of the optical fiber was located at the local Eureka airport, along with many other teams deploying sensors such as infrasound, seismic, and GPS.  The other 7 km of fiber was located along a remote dirt road in Newark Valley.”

With the help of this network, the team obtained a stunning profile of the sonic boom as it struck the ground. The DAS interrogators recorded an impulsive arrival with an extended coda that had similar features to those recorded by the seismometers and infrasound sensors. Whereas traditional sensors only measure sonic booms at one point, Dr. Donahue said that her team’s data revealed how the boom’s wavefront transformed as it impacted the irregular terrain of the Nevada landscape.

In addition to being the first time these methods were used to record an SRC reentry, the results of this test could have significant implications when it comes to predicting potential meteor and asteroid strikes. Said Dr. Donahue:

“By having an extremely dense array of sensors, DAS has the possibility of better characterizing the trajectory and size of a meteor. The topology (e.g., hills) of the ground is known to have an influence on wavefront recorded at the surface of the earth. By having a dense line of sensors that span over the changes in the earth’s elevation, these effects could be better accounted for to produce a more accurate characterization of a meteor’s trajectory.”

Following the completion of its primary mission, the OSIRIS-REx, NASA prepped the spacecraft for the next phase of its mission. In 2029, the spacecraft – renamed the OSIRIS-APEX (Apophis Explorer) – will rendezvous with the Near-Earth Asteroid 99942 Apophis and collect another sample.

Further Reading: GeoScienceWorld

The post Detection of a Space Capsule Entering Earth’s Atmosphere with Distributed Acoustic Sensing (DAS) appeared first on Universe Today.

The Andromeda Galaxy, our nearest large neighbour, has 36 identified dwarf galaxies. The Hubble telescope took images of Andromeda and its dwarfs during more than 1,000 orbits, creating a precise 3D map. Astronomers used these observations to reconstruct the dwarf galaxies’ star formation histories.

The results show that their environment plays a critical role in their star formation and their quenching.

When galaxies are quenched, they no longer form stars. It happens because the supply of star-forming gas is diminished or somehow made unavailable. This typically happens because of black hole feedback or when a galaxy moves through a dense galaxy cluster, and its gas is stripped away.

However, the dwarf galaxies around Andromeda (M31) seem to follow an unusual pattern of star formation and quenching. New research shows that the rambunctious environment around M31 is responsible.

The research is “The Hubble Space Telescope Survey of M31 Satellite Galaxies. IV. Survey Overview and Lifetime Star Formation Histories,” published in The Astrophysical Journal. Alessandro Savino from the Department of Astronomy at UC Berkeley is the lead author.

Astronomers aren’t certain how many dwarf galaxies the Milky Way has, but it looks like Andromeda, with its dozens of dwarf galaxies, has had a more active history of mergers and absorptions. M 31 may have merged with another massive galaxy a few billion years ago, and its abundant dwarf galaxies could be from its eventful past and its sheer mass.

“Our knowledge of low-mass galaxy formation has long been anchored by Milky Way (MW) satellite galaxies,” the authors write. “It remains unclear if the insights learned from MW satellites, and their particular formation pathways, are applicable to other satellite systems and low-mass galaxies in general.”

“There’s always been concerns about whether what we are learning in the Milky Way applies more broadly to other galaxies.”

Daniel Weisz, UC Berkeley.

Studying dwarf galaxies is challenging. We’re inside the Milky Way, which makes observing its outskirts difficult. Dwarf galaxies are also dim, adding to their detection difficulty. Detecting them in distant galaxies is likewise difficult. Comparing the MW low-mass dwarf galaxies with those in other galaxies means contending with multiple layers of difficulty. Fortunately, the Andromeda galaxy is wide open to observations.

This large photomosaic of Andromeda is from the Hubble. It’s the largest one ever assembled from NASA/ESA Hubble Space Telescope observations. Click on the image to access the full-size version. Image Credit: NASA, ESA, B. Williams (University of Washington)

“From >1000 orbits of HST imaging, we present deep homogeneous resolved star colour-magnitude diagrams that reach the oldest main-sequence turnoff and uniformly measured star formation histories (SFHs) of 36 dwarf galaxies associated with the M31 halo,” the authors write. They did the same for 10 additional fields in M31, M33, and the Giant Stellar Stream. M33 is the Triangulum Galaxy, the third largest member of the Local Group after M31 and the Milky Way. M33 is also one of M31’s satellites. The Giant Stellar Stream is a long ribbon of stars that are the remnants of a galaxy absorbed by M31.

For context, this image shows some of the main features around Andromeda, including the Giant Stellar Stream, M32, and NGC 205, another of Andromeda’s dwarf galaxies. Image Credit: Ferguson et al. 2000

The observations reveal a tight correlation between a dwarf’s star formation history, its mass, and its proximity to M31.

“We see that the duration for which the satellites can continue forming new stars really depends on how massive they are and on how close they are to the Andromeda galaxy,” said lead author Savino in a press release. “It is a clear indication of how small-galaxy growth is disturbed by the influence of a massive galaxy like Andromeda.”

Astronomers are in a difficult spot when it comes to studying galaxies in detail. Our own Milky Way is the only galaxy that’s open to detailed investigation. The temptation is to draw parallels between our knowledge of the MW and other galaxies.

“There’s always a tendency to use what we understand in our own galaxy to extrapolate more generally to the other galaxies in the universe,” said principal investigator Daniel Weisz of the University of California at Berkeley. “There’s always been concerns about whether what we are learning in the Milky Way applies more broadly to other galaxies. Or is there more diversity among external galaxies? Do they have similar properties? Our work has shown that low-mass galaxies in other ecosystems have followed different evolutionary paths than what we know from the Milky Way satellite galaxies.”

These detailed, 1,000-orbit observations of Andromeda are helping change this. They reveal a more chaotic environment than in the Milky Way.

“Everything scattered in the Andromeda system is very asymmetric and perturbed. It does appear that something significant happened not too long ago,” said Weisz.

One of the research’s surprising findings is that about half of M31’s dwarf galaxies lie along the same plane, called the Great Plane of Andromeda, and are moving in the same direction. “That’s weird. It was actually a total surprise to find the satellites in that configuration, and we still don’t fully understand why they appear that way,” said Weisz.

The galaxies along this plane don’t appear to be any different from those on the plane. “There is no difference between the median SFH (star formation history) of galaxies on and off the great plane of Andromeda satellites,” the authors write.

The researchers used colour-magnitude diagrams (CMDs), an important tool in astronomy, to learn more about the star formation history in Andromeda’s dwarf galaxies. CMDs plot a star’s magnitude, or brightness, with its colour. From these plots, astronomers can learn about the age of a stellar population and when star formation was quenched.

The CMDs showed that star formation in dwarf galaxies lasts much longer than expected. It started early and continued, albeit more slowly, by drawing from a reservoir of gas. These results are in sharp disagreement with simulations like TNG 50.

“Star formation really continued to much later times, which is not at all what you would expect for these dwarf galaxies,” said Savino. “This doesn’t appear in computer simulations. No one knows what to make of that so far.”

This figure from the team’s research shows the star formation history (SFH) in Andromeda’s halo, the Giant Stellar Stream, and M33. The red region represents the Epoch of Reionization, the black line shows the best-fit SFH and the grey shows systematic uncertainties. It shows that star formation started early and continued for a long time, albeit at a much slower rate. Image Credit: Savino et al. 2025.

The research also shows that the SFH is no different between dwarf galaxies on the Great Plane of Andromeda and those off of it.

This figure from the study shows the median SFH for the GPoA candidate members (blue line, left panel) and out-of-plane candidates (orange line, middle panel). The gray lines show the SFH of individual galaxies. The right panel shows a direct comparison between the median SFH of the two samples. Image Credit: Savino et al. 2025.

The SFH results in Andromeda are not what we see in the MW. This suggests that the environmental histories, tidal forces, and gas stripping experienced by M31 satellites are different than those around the Milky Way, leading to different star formation patterns over cosmic time. This could be the most significant finding and further exemplifies the risk of extrapolating our knowledge of the Milky Way to other galaxies.

“The results of this study represent a significant step forward in our understanding of the M31 satellite system,” the authors write in their conclusion. They point out that the SFHs they’ve developed will only be more valuable when combined with large data sets acquired in the future. Data sets of the spectral abundance of stars and their proper motions in M31 are being acquired, and some already exist.

Maybe they’ll be able to explain Andromeda’s dwarf galaxies’ unusual properties.

“We do find that there is a lot of diversity that needs to be explained in the Andromeda satellite system,” added Weisz. “The way things come together matters a lot in understanding this galaxy’s history.”

• Press Release:

The post Andromeda’s Dwarf Galaxies Reveal Unique Star Formation Histories appeared first on Universe Today.

Rogue planetary-mass objects, also known as free-floating planets (FFPs) drift through space alone, unbound to any other objects. They’re loosely defined as bodies with masses between stars and planets. There could be billions, even trillions of them, in the Milky Way.

Their origins are unclear, but new research says they’re born in young star clusters.

Some free-floating planets (FFPs) form the same way stars form by collapsing inside a cloud. The International Astronomical Union calls them sub-brown dwarfs. But that can’t account for all FFPs, or isolated planetary-mass objects (iPMOs) as they’re sometimes called.

New research in Science Advances shows how FFPs form in young star clusters where circumstellar disks interact with one another.

“This discovery partly reshapes how we view cosmic diversity.”

Lucio Mayer, University of Zurich

The research is titled “Formation of free-floating planetary mass objects via circumstellar disk encounters.” Zhihau Fu from the Department of Physics at the University of Hong Kong and the Shanghai Astronomical Observatory is the lead author, and Lucio Mayer from the University of Zurich is the corresponding author.

“PMOs don’t fit neatly into existing categories of stars or planets,” said corresponding author Meyer. “Our simulations show they are probably formed by a completely different process.”

Astronomers found some of the first evidence of PMOs in the Trapezium Cluster in the year 2,000. The Trapezium is a tight, open cluster of stars in Orion. It’s also relatively young, and half of its stars show dwindling circumstellar disks, a sign that planet formation is taking place. In the research published in 2,000, the authors wrote that “Approximately 13 planetary-mass objects are detected.”

This Hubble Space Telescope image shows the Orion Nebula with the three stars of Orion’s belt prominent. The Trapezium cluster is the bright clump of stars above and to the right of the belt. Most of Trapezium’s stars are obscured by dust. In 2,000, astronomers first found evidence of rogue planets in the Trapezium Cluster. Image Credit: By NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team – http://hubblesite.org/newscenter/newsdesk/archive/releases/2006/01/https://www.spacetelescope.org/news/heic0601/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1164360

Since then, astronomers have found many more PMOs and hundreds more candidates. Scientists have wondered about their origins, but so far, there are no widely accepted explanations.

“The origin of planetary mass objects (PMOs) wandering in young star clusters remains enigmatic, especially when they come in pairs,” the authors write in their new research. “They could represent the lowest-mass object formed via molecular cloud collapse or high-mass planets ejected from their host stars. However, neither theory fully accounts for their abundance and multiplicity.”

The researchers used hydrodynamic simulations to test another origin for PMOs and found that they have a unique origin story. Instead of forming in a collapsing cloud like stars or in a protoplanetary disk around a young star, they form in the dense environments in young star clusters. The densely packed environments provide another pathway for PMO formation.

In their simulations, the researchers recreated some of the conditions inside young star clusters where stars readily interact with one another. During close encounters between two stars, their circumstellar disks interact. They get stretched into a tidal bridge between the pair of stars, and the gas in the bridge is also compressed into a greater density.

In the simulations, these bridges collapse into filaments, and those filaments collapse even further into dense cores. Eventually, these cores form PMOs of about 10 Jupiter masses. This fruitful process produces many pairs and triplets of PMOs. Astronomers observe a high number of PMO binaries in some clusters, so these simulations appear to match observations.

“Many young circumstellar disks are prone to instabilities due to the self-gravity of disk gas, potentially leading to disk fragmentation and the formation of gaseous planets,” the authors explain in their paper. “Circumstellar disks appear even more unstable when perturbed by a stellar or circumstellar disk flyby.”

This figure from the research shows some of the simulation results. The top panel shows a pair of young stars with interacting circumstellar disks. Two dense cores are forming in the interaction. The bottom panel shows four snapshots from the simulation at different elapsed times. The binary PMOs form in the dense filaments generated in the stellar encounter. Image Credit: Fu et al. 2025.

Even stable and isolated disks can form PMOs during flybys. However, the formation of PMOs is dependent on the combined velocity of the interactions. “For high- and low-velocity encounters, the tidal bridge is either stretched too thin or torn apart by the stars, and thus, forming isolated cores becomes impossible,” the authors explain. The interaction velocity has to be in the middle range.

Some of their simulations also showed up to four PMO cores forming in the filaments. “The middle part of the tidal bridge contracts into thin filaments with line mass over the critical value for stability, forming up to four cores in one encounter,” the researchers write. They explain that the exact number of cores is determined by the length of the filaments and is “sensitive to random density fluctuations.” These fluctuations are very difficult to predict from the encounter parameters.

The PMOs display some particular characteristics. They’re likely to have their own disks, and they’re likely to be metal-poor because of where they get their dust from. “In addition, PMOs and their hosts are expected to be metal-poor since they inherit materials in the parent disks’ outskirts that are susceptible to dust drift and, thus, are metal-depleted,” the authors explain.

The authors calculate that in just one million years, which is the approximate age of the Trapezium Cluster, each star will experience 3.6 encounters with other stars. “The highly efficient PMO production channel via encounters can, therefore, explain the hundreds of PMO candidates (540 over 3500 stars) observed in the Trapezium cluster,” the authors write.

It’s important to note that the results only apply to dense clusters that force interactions between circumstellar disks. “This process can be highly productive in dense clusters like Trapezium forming metal-poor PMOs with disks. Free-floating multiple PMOs also naturally emerge when neighbouring PMOs are caught by their mutual gravity,” the authors write.

“This discovery partly reshapes how we view cosmic diversity,” said co-author Lucio Mayer. “PMOs may represent a third class of objects, born not from the raw material of star forming clouds or via planet-building processes, but rather from the gravitational chaos of disk collisions.”

PMOs can be difficult to spot, so their population is based on preliminary estimates and understandings. But they’re out there, and we’ll only get better at identifying them.

This artist’s impression shows an example of a rogue planet with the Rho Ophiuchi cloud complex visible in the background. Rogue planets have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Image Credit: ESO/M. Kornmesser/S. Guisard

The Upper Scorpius Association contains the next highest-known population of PMOs. A 2021 study identified between 70 and 170 candidate PMOs in the region.

The soon-to-see-first-light Vera Rubin Observator (VRO) will significantly grow the number of known PMOs. More data is better data, and the VRO’s observations will lead to a better understanding of how they form.

“Future studies of various young clusters can further constrain the population of PMOs,” the authors conclude.

• Press Release: Young Star Clusters Give Birth to Rogue Planetary-Mass Objects
• New Research: Formation of free-floating planetary mass objects via circumstellar disk encounters

The post Rogue Planets are Born in Young Star Clusters appeared first on Universe Today.

The effects of Climate Change on Earth’s living systems have led to a shift in biological studies, with attention now being focused on the boundaries within which life can survive. Studying life forms that can thrive in extreme environments (extremophiles) is also fundamental to predicting if humans can live and work in space for extended periods. Last, but not least, these studies help inform astrobiological studies, allowing scientists to predict where (and in what form) life could exist in the Universe.

In a recent study, a team of Italian researchers used brine shrimp (Artemia franciscana) in the earliest stage of development (nauplii) and subjected them to Mars-like pressure conditions. Their results indicate that while the nauplii experienced physiological changes, their development remained largely unchanged. This not only demonstrates that extremophiles show great adaptability and can survive in Mars-like conditions. It also indicates that similar life forms could be found elsewhere in the Universe, representing new opportunities for astrobiological research.

Maria Teresa Muscari Tomajoli, an Astrobiology PhD Candidate at the Parthenope University of Naples, led the study. She was joined by Paola Di Donato, a Professor of Organic and Biological Chemistry at Parthenope. They were joined by researchers from the Federico II University, the INAF-Institute of Space Astrophysics and Planetology (INAF-ISAP), the INAF-Osservatorio Astronomico di Capodimonte, and the Italian Institute for Nuclear Physics (INFN). The paper that details their findings was part of a special volume titled Comparative Biochemistry and Physiology A: Molecular & Integrative Physiology.

Brine Shrimp Artemia franciscana. Credit: Wikipedia

On Earth, extremophiles belong to all three domains of life (Archaea, Bacteria, and Eukarya). They are characterized by their ability to withstand pressure, acidity, temperatures, and other conditions that would be fatal to other organisms. After Earth, Mars is considered the most habitable planet after Earth in the Solar System, hence why most of humanity’s astrobiology efforts are focused there. In addition to the low atmospheric pressure (1/100th of Earth’s at sea level), the surface is subject to extreme temperature variations and is contaminated by perchlorites and toxic metals.

Scientists speculate that if life exists on Mars today, it will likely take the form of microbes living in high-salinity briny patches beneath the surface. As Tomajoli told Universe Today via email, this makes extremophiles (like Artemia franciscana) ideal test subjects for predicting what life is like in similar planetary environments:

“The definition of life is crucial, especially when searching for traces of it on other planetary bodies (e.g., Mars), where life might not exist as we traditionally imagine it. Artemia cysts present an interesting case: in their dormant state, they cannot be classified as living but rather as potential life. Studying organisms with such characteristics helps broaden the perspective in astrobiological research.”

In particular, extremophiles present opportunities for researching species adaptation, which has become a major focus of scientific research due to anthropogenic Climate Change. Worldwide, rising carbon emissions and increasing temperatures are leading to changes in weather patterns, increased ocean acidity, drought, wildfires, and the loss of habitats. As a result, countless marine and terrestrial species are forced to adapt to conditions that are becoming more extreme.

In this April 30, 2021, file image taken by the Mars Perseverance rover and made available by NASA, the Mars Ingenuity helicopter, right, flies over the surface of the planet. Credit: NASA/JPL-Caltech/ASU/MSSS

“In the context of climate change, life conditions are shifting toward extreme boundaries, making survival more challenging for many organisms,” Tomajoli added. “Extremophiles, which thrive in Earth’s most remote environments, are valuable models for understanding metabolic adaptations. Their apparent simplicity is, in fact, an advantage, allowing them to adapt better than more complex organisms to extreme environmental constraints.”

Tomajoli and her colleagues chose Artemia franciscana for their study, a species of brine shrimp known to thrive in high-salinity environments. The eggs they produce, known as cysts, are dormant and can be stored indefinitely, making them extremely useful for aquaculture and scientific research. As Tomajoli indicated, they have also been used in previous space missions, including the Biostack experiment on the Apollo 16 and 17 missions and the ESA’s EXPOSE platform mounted on the International Space Station’s (ISS) exterior.

These experiments all tested the resilience of certain life forms and their progeny to cosmic rays. However, as Tomajoli added, no further studies have been conducted regarding the physiological adaptations of Artemia franciscana, and there is currently no scientific literature available on the topic:

“In particular, Artemia brine shrimps are considered halophiles (literally “salt-loving” organisms) and thrive in environments that can be considered Mars analogs (or laboratories for Mars studies) such as temporary lakes that undergo frequent evaporation, prompting Artemia to produce cryptobiotic cysts. Additionally, Artemia is an easily cultivable model, making it suitable for biological and astrobiological experiments. A recent article by Kayatsha et al., 2024  also showed that Artemia franciscana was among all the microinvertebrates that were tested, the more resistant one to perchlorates salts present in the regolith of simulated martian soil.”

Artist’s impression of water under the Martian surface. Credit: ESA

For their experiment, Tomajoli and her colleagues placed dormant cysts in Mars-like pressure conditions. Once they hatched into nauplii, the team analyzed their aerobic and anaerobic metabolism, mitochondrial function, and oxidative stress. As indicated in their paper, brine shrimp born in Martian pressure conditions managed to adapt quite well. They further share how these results could lead to further studies to evaluate the metabolic adaptations of the cysts to longer exposure times, combinations of different Mars-like conditions, or studies of the adaptations of the nauplii in other stages of development:

“Artemia franciscana showed an exciting potential for physiological adaptations, enabling organisms to cope with the environmental challenges they encounter in space… Nauplii’s cells appear to activate responses to avoid mitochondrial dysfunction and continue their growth processes. These adaptation mechanisms highlight Artemia franciscana’s resilience and ability to thrive in hostile environmental conditions. The results reported in this study further support the potential use of Artemia franciscana for astrobiological purposes, highlighting the animals’ metabolic and redox state changes as a response to adaptation to an extreme condition mimicking the space.”

The implications of this research are far-reaching, embracing astrobiology, human space exploration, and mitigating the effects of Climate Change. Not only could it help point the way toward potential life on Mars, in the interior oceans of icy bodies, and other extreme environments. It could also inform future missions to Mars and other deep-space destinations, where astronauts will need to rely on closed-loop bioregenerative life support systems (BLSS), grow their own food, and conduct research into the effects of exposure to lower gravity, elevated radiation, and other harsh conditions.

At home, the study of extremophiles and adaptation mechanisms could provide insight into climate resilience and adaptation, consistent with the goals outlined in the Sixth Assessment Report (AR6) by the Intergovernmental Panel on Climate Change (IPCC). As they summarize in their paper:

“Understanding the mechanisms of Artemia franciscana adaptations to space-simulated conditions could provide new insights into the study of the limits of life, as well as contribute to the search for biosignatures—traces of past life on other planetary bodies. Additionally, it could offer a viable solution for the long-term survival of human space missions, helping establish self-sustaining populations in confined environments. Artemia could serve as a renewable food source for astronauts, given its richness in essential nutrients, including proteins, lipids, and vitamins.”

Tomajoli and her colleagues have also conducted simulations with a full Mars-like atmosphere for longer periods of time. The paper describing this experiment will be released soon. In the meantime, the search for life on Mars and beyond continues. Knowing it can exist out there and under what conditions will help narrow that search and encourage us to keep investigating.

Further Reading: Science Direct

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Our Milky Way Galaxy is rich in dark matter. The problem is, we can’t see where it’s distributed because, well, it’s dark. We also don’t completely understand how it’s distributed—in clumps or what? A team at the University of Alabama-Huntsville has figured out a way to use solitary pulsars to map this stuff and unveil its effect on the galaxy.

A technique developed by Dr. Sukanya Chakrabarti and her team is based on some unique characteristics of pulsars. In addition, it uses the presence of a strange wobble of our galaxy. It seems to be induced by interactions with dwarf galaxies such as the Large Magellanic Cloud. That wobble has a connection to the amount of dark matter in the galaxy, and it turns out that pulsars can help map it.

Dark Matter Mapping and Pulsars

Pulsars are the corpses of massive stars. After they explode as supernovae, what remains is a rapidly spinning compressed stellar core. These beasts sport incredibly strong magnetic fields. Those fields twist and coil up as they spin many times per second and send high-speed particles out to space. That causes the pulsar to lose energy. Combined with friction produced by the motions of the twisted magnetic field, the pulsar slows down ever so slightly in a process called “magnetic braking”. Scientists have worked for years to model this process to understand the behavior of pulsars.

Illustration of a pulsar with powerful magnetic fields. They funnel particles to space, and their twisting characteristics help to slow down a pulsar’s spin. That spin is accelerated by the effect of dark matter distribution. Credit: NASA’s Goddard Flight Center/Walt Feimer

The Milky Way Galaxy’s behavior is another part of the dark matter mapping puzzle. Astronomers know it has a substantial component of dark matter that appears not to be evenly spread out. The actual distribution of that mass of dark matter leads to some interesting effects, according to Chakrabarti. “In my earlier work, I used computer simulations to show that since the Milky Way interacts with dwarf galaxies, stars in the Milky Way feel a very different tug from gravity if they’re below the disk or above the disk,” she said. “The Large Magellanic Cloud (LMC)–a biggish dwarf galaxy–orbits our own galaxy, and when it passes near the Milky Way, it can pull some of the mass in the galactic disk towards it–leading to a lopsided galaxy with more mass on one side, so it feels the gravity more strongly on one side.”

Gaia showed our galaxy’s disk, the dark brown horizontal spanning from one side to the other, has a wave. Gaia also showed that the Milky Way has more than two spiral arms. They aren’t as pronounced as we thought. The galaxy’s distribution of dark matter contributes to the shape. Image Credit: ESA/Gaia/DPAC, Stefan Payne-Wardenaar CC BY-SA 3.0 IGO

Chakrabarti compared this interesting galaxy “wobble” to the way a toddler walks–not entirely balanced yet. That wobble affects stars, including pulsars. And it turns out that the different tugs of gravity caused by the distribution of dark matter affects their spindown rates. “So this asymmetry or disproportionate effect in the pulsar accelerations that arises from the pull of the LMC is something that we were expecting to see,” said Chakrabarti. In other words, those tugs of gravity by dark matter give away its distribution and possibly its density throughout the Galaxy.

Building on Previous Work

Chakrabarti and her team previously pioneered the use of binary pulsars to map dark matter in the Galaxy. It turns out that magnetic braking doesn’t affect the orbits of pulsars in binary systems. That makes them useful to measure the amount and distribution of dark matter in the Milky Way. So, the team measured the acceleration of pulsar spin rates due to the effect of the Milky Way’s gravitational potential. That work showed it’s possible to map the galaxy’s gravitational field with data points from more binary pulsars. That includes clumps of galactic dark matter. However, there’s a problem. There are a lot of singular pulsars. There had to be a way to use them, too. And that brings us back to the team’s modeling of pulsar spindown.

Artist’s impression of a binary pulsar by Michael Kramer, Jodrell Bank Observatory. Binaries help map dark matter’s effect on the gravitational field of the galaxy.

“Because of this spindown, we were initially–in 2021 and in our follow-up 2024 paper–forced to use only pulsars in binary systems to calculate accelerations because the orbits aren’t affected by magnetic braking,” said team member Tom Donlon. “With our new technique, we are able to estimate the amount of magnetic braking with high accuracy, which allows us to also use individual pulsars to obtain accelerations.”

Need More Data

Adding more “point source” measurements with single pulsars, Chakrabarti’s team predicts that it should eventually be possible to determine a much more accurate understanding of the distribution of dark matter in the Milky Way. “In essence, these new techniques now enable measurements of very small accelerations that arise from the pull of dark matter in the galaxy,” Chakrabarti said. “In the astronomy community, we have been able to measure the large accelerations produced by black holes around visible stars and stars near the galactic center for some time now. We can now move beyond the measurement of large accelerations to measurements of tiny accelerations at the level of about 10 cm/s/decade. 10 cm/s is the speed of a crawling baby.”

For More Information

UAH Breakthrough Enables the Measurement of Local Dark Matter Density Using Direct Acceleration Measurements for the First Time
Empirical Modeling of Magnetic Braking in Millisecond Pulsars to Measure the Local Dark Matter Density and Effects of Orbiting Satellite Galaxies
Galactic Structure From Binary Pulsar Accelerations: Beyond Smooth Models

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Neutrinos generated through solar fusion reactions travel effortlessly through the Sun’s dense core. Each specific fusion process creates neutrinos with distinctive signatures, potentially providing a method to examine the Sun’s internal structure. Multiple neutrino detection observatories on Earth are now capturing these solar particles, which can be analysed alongside reactor-produced neutrinos with the data eventually enabling researchers to construct a detailed map of the interior of the Sun.

The Sun is a massive sphere of hot plasma at the centre of our solar system and provides the light and heat to make life on Earth possible. Composed mostly of hydrogen and helium, it generates energy through nuclear fusion, converting hydrogen into helium in its core. This process releases an enormous amount of energy which we perceive as heat and light. The Sun’s surface, or photosphere, is around 5,500°C, while its core reaches over 15 million°C. It influences everything from our climate to space weather, sending out solar wind and occasional bursts of radiation known as solar flares. As an average middle-aged star, the Sun is about 4.6 billion years old and will (hopefully) continue burning for another 5 billion years before evolving into a red giant and eventually becoming a white dwarf.

This image shows our Sun during a period of high activity.

The standard solar model (SSM) is used to understand and predict the Sun’s internal structure and evolution, it’s how we work out what’s going on inside the Sun. It explains how, in the Sun’s core, different nuclear fusion reactions are constantly pumping out neutrinos – tiny, nearly massless particles that travel through almost anything. Each type of reaction creates neutrinos with their own properties. These neutrinos may help us to understand more about the interior of the Sun. Right now, we only know about its internal density structure from theoretical models based on the SSM, matched with what we can see on the Sun’s surface. The neutrinos may hold the information that will gives us more direct data about the solar interior. 

Chinese researchers are working on a new neutrino observatory called TRIDENT. They built an underwater simulator to develop their plan. Image Credit: TRIDENT

In a paper published by Peter B. Denton from the Brookhaven National Laboratory and Charles Gourley from Rensselaer Polytechnic Institute they show how solar neutrinos can help us to look inside the Sun and establish its density structure. In contrast, photons of light only tell us about the surface of the Sun as it is right now, and give us a little information about the Sun’s interior hundreds of thousands of years ago. This delay in photons exiting the Sun is because they bounce around the dense solar interior for centuries before escaping. Neutrinos on the other hand give us up to the minute information because they can zip straight through the Sun without getting stopped. 

It has long since been known that neutrinos change their flavour or type (electron neutrino, muon neutrino or tau neutrino) as they travel through matter and that depends on the local density. This is well documented as the Mikheyev-Smirnov-Wolfenstein effect and, by measuring the flux of the neutrino as observed at Earth, compared to unoscillating  predicted flux, the density where the neutrinos were produced can be calculated. Input is also required from independent measurements from neutrino oscillations  that have been created inside nuclear reactors. 

The team demonstrate that the approach does have its limitations  and that there are constraints on just how much density information can be gleaned from the SSM alone. Further data from projects like JUNO and DUNE are needed to further improve the solar internal density profile and give us a more realistic view of the internal workings of our local star.

Source : Determining the Density of the Sun with Neutrinos

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Innovation is a history of someone trying to build a better mouse trap – or at least that’s how it’s described in business school. But what happens if someone tries to build a better version of something that isn’t even commonly used yet? Maybe we will soon find out, as NASA recently supported an effort to build a better type of solar sail as part of its Institute for Advanced Concepts (NIAC) program.

The project, called “The Ribbon” on its announcement page, is a novel take on a typical solar sail and is being developed by a company called TestGuild Engineering out of Boulder, which seems to be run by a sole proprietor known as Gyula Greschik, who also appears to be a researcher at UC Boulder. The Ribbon consists of a “film strip with a diffractive grating” that uses the same principle as a traditional solar sail to move – light pressure. 

The diffractive grating is the key here – when the Ribbon is oriented towards the light from the Sun, the light effectively “pushes” it, just like a solar sail. But, in this case, the diffractive grating causes the force to be directed toward the “leading end” of the Ribbon. Importantly, it does this with no structure components at all – just the Ribbon itself.

Fraser discusses how awesome solar sails are.

If a payload is attached to the other end, eventually, the force being applied to the front will drag the back along with it. It might not happen immediately, but like an actual ribbon, eventually, the force will be transferred down to the payload. That would allow it to effectively tow the payload, much like a traditional solar sail.

This does have some unique advantages, including its ease of storability and potentially infinite scaling—longer ribbons would simply mean more force, much like a larger solar sail would also mean more force. In theory, at least, there is no limit to the scaling of how large you could make the Ribbon, though practically, eventually, you would hit the physical limits of the material you chose to make it out of.

TestGuild has some experience developing projects for NASA already. Back in 2017, it was given a Small Business Innovation Research grant to work on a type of deployable communications array that uses similar structural engineering techniques to the Ribbon. It’s unclear whether that project is still ongoing, but given the new interest from NASA on a completely separate use case with the same PI, it likely isn’t.

Fraser discusses the basic concept behind solar sails.

 Comparing the Ribbon’s use cases to those of more traditional solar sails will take a long time. NIAC Phase I typically takes about a year. In the press release announcing the project, Dr Greschik notes that most of this round will be focused on simulation and feasibility studies. Special emphasis is placed on how the Ribbon responds to small perturbations and what control system would be necessary to stabilize it. So, it may be some time before we see a giant Ribbon pulling a payload through space. However, new solar sail concepts always pop up, and this one could provide some inspiration for the next generation of designs, or it could see itself manifested one day.

Learn More:
Greschik & NASA – The Ribbon
UT – NASA’s Putting its Solar Sail Through its Paces
UT – Project Helianthus – a Solar Sail Driven Geomagnetic Storm Tracker
UT – Solar Sails Could Reach Mars in Just 26 Days

Lead Image:
Artist’s concept of the Ribbon.
Credit – NASA / Gyula Greschik

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Chemical rockets are loud, noisy and can only get us so far. If we want to reach another star system, we’ll need something better—either super energy-dense fuel to improve the efficiency of chemical rockets or a way to push spacecraft using beams of energy, like a photonic lightsail. A new paper looks at the pros and cons of lightsails, figures out the best setup to carry a small payload to another star while humans are still alive to see it, and checks out what materials might actually work for this kind of mission.

Interstellar travel, or journeying between stars, represents one of our most ambitious challenges. While current technology limits us to exploring the solar system, the dream of reaching distant star systems drives scientific innovation and imagination. Such journeys would require advanced propulsion systems, like nuclear fusion engines, solar sails, or theoretical concepts such as warp drives and wormholes (must resist any reference to Star Trek.) The immense distances between the stars present enormous challenges in terms of time, energy, and resource management. Shielding from radiation, life support and the psychological effects of isolation are among the challenges yet still, the pursuit of interstellar travel continues to inspire.

Artistic rendition of an interstellar spacecraft traveling near the speed of light. Credit: Made with ChatGPT

A new paper authored by a team led by Jadon Y. Lin from the University of Sydney explores one possible technology that may get, if not us then our technology, to the stars. They explore the principles of lightsail technology and how the application of photons of light could drive spacecraft the immense distances. Starting with the desired outcome, the team use a computational method which starts with a desired outcome and work backwards to get the best solution to achieve it. 

DALL-E illustration of a light sail

Just what is the problem. Travelling even relatively short distances among the stars, such as to Proxima Centauri ‘just’ 4.2 light years away, a spacecraft would need to travel at over 10% the speed of light to get there in a human lifetime! That’s approximately 30,000 km per second when our fastest probe has only achieved 194 kilometres per second! We need to go faster! According to the Tsiolkovsky rocket equation, chemical propulsion to accelerate a single proton to that speed would require more fuel than the entire observable universe! That means any spacecraft aiming for such enormous speeds needs an external source of momentum and energy. Enter light sail technology which could, according to recent research propel a probe to Proxima Centauri in just 21 years!

This image of the sky around the bright star Alpha Centauri AB also shows the much fainter red dwarf star, Proxima Centauri, the closest star to our Solar System. New research shows that material from Alpha Centauri has reached our Solar System, mostly in the form of tiny rocks. Image Credit: Digitized Sky Survey 2. Acknowledgement: Davide De Martin/Mahdi Zamani

Fundamental to the success of a functional lightsail for interstellar travel hinges on finding the right materials and fabrication methods for the sail itself. There are some promising options available such as silica, silicon nitride and molybdenum disulfide although their full properties in ultra-thin membranes have still to be tested. The team conclude that molybdenum disulfide is currently the best contender but further testing is needed. Shifting the focus to design, the traditional sail shapes show potential but the paper concludes that they are outperformed by nano-structured designs like diffraction gratings, which optimise propulsion, thermal control, and stability. 

Sadly interstellar lightsails might yet take decades to become a reality. The technology isn’t quite there yet, not just in material science but progress is needed in areas like metalenses and high-powered lasers too. We have already seen light sails used successfully in space but, as interest develops and technology advances, slowly, interstellar spacecraft designs may at least one day becoming a reality. 

Source : Photonic Lightsails: Fast and Stable Propulsion for Interstellar Travel

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Any satellite sent to space must be able to deal with the battle with Earth’s gravitational pull, withstanding the harsh conditions of launch before reaching the zero-gravity environment it was designed for. But what if we could send raw materials into orbit and build the satellite there instead? DARPA (the Defence Advanced Research Projects Agency) has formed partnerships with a number of universities to develop 3D printing technology and in-orbit assembly of satellite components. It’s recently put out a new request for proposals to explore biological growth mechanisms in space – the exciting prospect of living organisms that can increase in size, develop structures, and repair themselves.

Satellite launches from Earth began on October 4, 1957, when the Soviet Union successfully launched Sputnik 1, the world’s first artificial satellite. It marked the beginning of the space age and was followed by the U.S. launch of Explorer 1 in 1958. Over the decades that followed, advancements in rocketry culminated in the development of Saturn V capable of delivering humans to the Moon. The 1960s and 1970s saw the rise of communication, weather, and reconnaissance satellites and with the advent of reusable spacecraft like the Space Shuttle in the 1980s space became more economical. 

The Sputnik spacecraft stunned the world when it was launched into orbit on Oct. 4th, 1954. Credit: NASA

One of the biggest challenges facing agencies launching space satellites is the challenge of size and weight. The bigger and heavier it is, the more expensive it is to launch. DARPA’s 2022 NOM4D program aims to solve this by sending lightweight materials to space for on-site construction, rather than build them before launch. This innovative approach enables building much larger, more mass-efficient structures into orbit that would perhaps otherwise be impossible to launch fully assembled. The idea opens new possibilities for optimised designs that aren’t limited by launch vehicle dimensions and lifting capability. 

The partnerships established by DAPRA include Caltech (the California Institute of Technology) and the University of Illinois Urbana-Champaign have already demonstrated wonderful advances in the first two phases. They are now continuing phase 3 with launch companies to undergo in-space testing of the assembly process. In many ways though, the concept is not new, the ISS for example has been built in orbit over many decades, it’s the first time however that the approach is being used for smaller satellites. 

International Space Station. Credit: NASA

The Caltech experiment will operate independently in orbit without human interaction once deployed. It’s going to be fascinating to watch this momentous test. On-board cameras will provide live monitoring of the construction process as an autonomous robot assembles lightweight composite fibre tubes into a circular truss 1.4 meters in diameter, representing an antenna structure. It’s a little bit like popular children’s toys like K’Nex but of course, a little more advanced. 

If successful, the technology could be scaled up to eventually construct space-based antennas exceeding 100 meters in diameter, transforming space exploration with enhanced communicating and monitoring capabilities. It goes much further than this though. DARPA is now exploring the possibility of “growing” large biological structures in space too. 

Recent advances in metabolic engineering, knowledge of extremophile organisms and developments in tunable materials like hydrogels are making space grown organic structures a tantalising possibility. It aims to DAPRA have put out a request for proposals to explore the concept. These biologically manufactured structures could enable projects that are impractical with traditional methods with dreams of space elevator tethers, orbital debris capture nets and expandable commercial space station modules perhaps not so far from being a reality. By harnessing biological growth in the unique conditions of space, entirely new construction possibilities may become feasible. Just imagine!

Source : DARPA demos will test novel tech for building future large structures in space and Large Bio-Mechanical Space Structures

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NASA’s asteroid-studying spacecraft Lucy captured an image of its next flyby target, the asteroid Donaldjohanson. On April 20th, the spacecraft will pass within 960 km of the small, main belt asteroid. It will keep imaging it for the next two months as part of its optical navigation program.

Donaldjohanson is an unwieldy name for an asteroid, but it’s fitting. Donald Johanson is an American paleoanthropologist who discovered an important australopithecine skeleton in Ethiopia’s Afar Triangle in 1974. The female hominin skeleton showed that bipedal walking developed before larger brain sizes, an important discovery in human evolution. She was named Lucy.

NASA named their asteroid-studying mission Lucy because it also seeks to uncover clues about our origins. Instead of ancient skeletal remains, Lucy will study asteroids, which are like fossils of planet formation.

During its 12-year mission, Lucy will visit eight asteroids. Two are in the main belt, and six are Jupiter trojans. Asteroid Donaldjohanson is a main-belt, carbonaceous C-type asteroid—the most common variety—about 4 km in diameter and is Lucy’s first target. It’s not one of the mission’s primary scientific targets. Instead, the flyby will give Lucy mission personnel an opportunity to test and calibrate the spacecraft’s navigation system and instruments.

This image depicts the two areas where most of the asteroids in the Solar System are found: the asteroid belt between Mars and Jupiter and the Trojans, two groups of asteroids moving ahead of and following Jupiter in its orbit around the Sun. Image Credit: NASA

The animation below blinks between images captured by Lucy on Feb. 20th and 22nd. It shows the perceived motion of Donaldjohanson relative to the background stars as the spacecraft rapidly approaches the asteroid.

via GIPHY

The flyby is like a practice run before Lucy visits the Jupiter trojans. These asteroids are clusters of rock and ice that never coalesced into planets when the Solar System formed. These are the “fossils of planet formation,” the most well-preserved evidence from the days of Solar System formation.

Currently, Donaldjohanson is 70 million km away and will remain a tiny point of light for weeks. Only on the day of the encounter will the spacecraft’s cameras capture any detail on the asteroid’s surface. In the images above, the dim asteroid still stands out from the dimmer stars of the constellation Sextans. Lucy’s high-resolution L’LORRI instrument, the Long Lucy LOng Range Reconnaissance Imager, captured the images.

Lucy is following a unique flight pattern. It’s essentially a long figure-eight.

Illustration of the Lucy spacecraft’s orbit around Jupiter, which will allow it to study its Trojan population. Though the image lists 6 flybys, the spacecraft will visit 8 asteroids. One of the listed ones is a binary, and the spacecraft already encountered the asteroid Dinkinesh. Image Credit: SwRI

Even this early in its mission, Lucy has delivered some surprising results. In November 2023, it flew past asteroid 152830 Dinkinesh. The flyby was intended as a test for the spacecraft’s braking system, but instead, it revealed that Dinkinesh has a small satellite. Closer observations showed that the satellite is actually a contact binary, which means it’s composed of two connected bodies. This was a valuable insight into asteroids.

These two images from Lucy show the asteroid Dinkinesh and its satellite Selam. The first image (L) shows Selam just coming into view behind Dinkinesh. The second image (R) reveals that Selam is actually two objects, a contact binary. Image Credits: By NASA/Goddard/SwRI/Johns Hopkins APL/NOIRLab – Public Domain, https://commons.wikimedia.org/w/index.php?curid=139996127

There are surprising discoveries in every mission, and Lucy is no exception. As it makes its way through its list of targets, it will almost certainly show us some surprises.

The Trojans are difficult to study from a distance. They’re a long way away. Scientists aren’t certain how many there are; there may be as many Trojans as there are main-belt asteroids. The Trojans exhibit a wide variety of compositions and characteristics, which could indicate that they came from different parts of the Solar System. By studying the Trojans in all their diversity, Lucy will hopefully help scientists reconstruct their origins and how they were captured by Jupiter.

The Solar System has a long history and we’ve only just become a part of it. Some of the clues to our origins are out there among the battered rocks of the asteroid belt and the Jupiter Trojans. Lucy will give us our best look at the Trojans. Who knows what it might reveal?

• Press Release: NASA’s Lucy Spacecraft Takes Its 1st Images of Asteroid Donaldjohanson
• Press Release: NASA Lucy Images Reveal Asteroid Dinkinesh to be Surprisingly Complex
• ASU Institute of Human Origins: Lucy’s Story

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If you’ve ever looked at Mars through a telescope, you probably noticed its two polar ice caps. The northern one is made largely of water ice—the most obvious sign that Mars was once a wetter, warmer world. A team of researchers from the German Aerospace Center (DLR) used that ice cap to make surprising discoveries about it and what it tells us about Mars’s interior.

According to Adrien Broquet and a team of DLR planetary scientists, the northern polar cap on Mars is quite young. They found this out by applying techniques used to measure what ice sheets on Earth do to its surface. The effect that widespread glaciation has is called “glacial isostatic adjustment,” and it’s still happening in places such as Scandinavia. Essentially, it’s a constant movement of land as Earth’s surface deforms in response to the weight of ice. The rate of deformation depends on the specific characteristics of the underlying mantle.

Large areas of our planet have been covered at times by thick glacial sheets. The last time this occurred was during a glacial period that ended about 11,700 years ago. Those sheets “weighed down” the surface, compressing it. As the glaciers melted, the surface began to rise back up in a process called “isostatic rebound”. The rate of both depression and the subsequent rising motion tells something about Earth’s interior, particularly the mantle. Think of pushing down on a sponge and then watching as it expands when you take your hand away.

Mars is permanently covered by water ice at its north pole. The ice sheet here is approximately 1000 kilometres in diameter and up to three kilometres thick, and its load depresses the rocky crust beneath. Credit: ESA/DLR/FU Berlin, NASA MGS MOLA Science Team Studying a Rebounding Ice Cap

Broquet and his team decided to measure glacial isostatic rebound on Mars under the northern ice cap. It’s about 1,000 kilometers wide and three kilometers thick. They studied its formation by combining models of the planet’s thermal evolution with calculations of glacial isostatic adjustment, along with gravity, radar, and seismic observations.

The team concluded that the Martian northern polar cap is quite young, and it’s depressing the ground underneath. “We show that the ice sheet pushes the underlying ground into the mantle at a rate of up to 0.13 millimetres per year,” said Broquet. That’s a fairly small deformation, according to team member Ana-Catalina Plesa. “The small deformation rates indicate that the upper mantle of Mars is cold, highly viscous and much stiffer than Earth’s upper mantle,” she said.

Understanding Planetary Construction

So, how can measurements of ice weighing down planetary surfaces tell us so much? Remember that rocky planets like Earth and Mars are in constant states of change. Those changes can range from short-lived events like volcanic eruptions to long-lived ones like Ice Ages. Each alteration affects the surface, as does the rate at which the surface deforms and “bounces back”. Earth scientists use techniques such as the study of glacial isostatic adjustment to probe deep beneath the surface to understand the characteristics of those layers.

When ice weighs down the surface, the amount of depression depends on the mantle’s viscosity. That’s a measure of how much the mantle’s rocky materials resist flowing. Earth’s mantle rocks are more than a trillion times more viscous than asphalt. They still deform, however, and flow over geological timescales of millions of years. Using radar data and other methods to study the rate of depression and rebound of Earth’s surface, scientists can find the mantle viscosity. As it turns out, when you apply the same methods to Mars, it presents some surprises, including a seemingly cold north pole and the recently volcanically active equatorial regions.

Estimating Mars’s Interior

To understand why the Mars interior is the way it is, you need estimates of Mars’s gravity field (which varies), seismic measurements made by the InSight lander, and other data. They all help to determine rates of depression and rebound on the Red Planet’s surface and interior. The result? It appears that the surface under the Martian north pole has not had nearly enough time to fully deform under the weight of the ice. Broquet’s group estimates that Mars’s north pole surface area is currently subsiding at rates of up to 0.13 millimeters per year. For it to be that slow, the underlying upper mantle viscosity tells us that the Martian interior is quite cold.

The team’s measurements indicate the ice cap is young—well more than any other large-scale feature seen on the planet. It’s most likely to be between 2 and 12 million years.

Artist illustration of Mars Insight Lander. It measured seismic activity on Mars, giving further insight into the subsurface structure. Credit: NASA/JPL

Other places on the planet may not be quite so frigid as the polar regions. “Although the mantle underneath Mars’s north pole is estimated to be cold, our models are still able to predict the presence of local melt zones in the mantle near the equator,” said study co-author Doris Breuer.

These findings represent the first time that scientists found glacial isostatic adjustment operating on another rocky planet. Future missions to Mars could include more instruments to measure the rise and fall of the Martian surface in response to glaciation.

For More Information

Mars’s Northern Ice Cap is Young with a Cold, Stiff Mantle Beneath
Glacial Isostatic Adjustment Reveals Mars’s Interior Viscosity Structure

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Our Solar System is in motion and cruises at about 200 kilometres per second relative to the center of the Milky Way. During its long journey, it has passed through different parts of the galaxy. Research shows that the Solar System passed through the Orion star-forming complex about 14 million years ago.

The Orion star-forming complex, also known as the Orion molecular cloud complex, is part of a larger structure called the Radcliffe Wave (RW). The RW was discovered very recently, in 2020. It’s a large, coherent structure that also moves through the galaxy. It’s a wave-like structure of gas and dust that holds many star-forming regions, including the well-known Orion complex and the Perseus and Taurus molecular clouds. It’s almost 9000 light-years long and is within the Milky Way’s Orion arm.

The environment in the RW and the Orion complex is more dense, and when the Solar System passed through it, the greater density compressed the Sun’s heliosphere. This allowed more interstellar dust to enter the Solar System and reach Earth. According to new research, this affected Earth’s climate and left its mark on geological records.

The research, “The Solar System’s passage through the Radcliffe wave during the middle Miocene,” was published in the journal Astronomy and Astrophysics. The lead author is Efrem Maconi, a doctoral student at the University of Vienna.

“We are inhabitants of the Milky Way.”

João Alves, professor of astrophysics, University of Vienna

“As our Solar System orbits the Milky Way, it encounters different Galactic environments with varying interstellar densities, including hot voids, supernova (SN) blast wavefronts, and cold gas clouds,” the authors write. “The Sun’s passage through a dense region of the interstellar medium (ISM) may impact the Solar System in several ways.”

14 million years ago, Earth was in the Middle Miocene Epoch. Notable events took place in the Miocene. Afro-Arabia collided with Eurasia, mountains were actively building on multiple continents, and the Messinan Salinity Crisis struck the Mediterranean. Overall, the Miocene is known for the Middle Miocene Climatic Optimum (MMCO). During the MMCO, the climate was warm, and the tropics expanded.

However, the Miocene is also known for something else: the Middle Miocene Disruption (MMD). The MMD followed the MMCO and saw a wave of extinctions strike both terrestrial and aquatic life. It happened around 14.8 to 14.5 million years ago, which is in line with when the Solar System passed through the Radcliffe Wave and the Orion complex.

The authors of the new research say the Solar System’s passage through the RW and the Orion complex could be responsible for the MMD.

“Imagine it like a ship sailing through varying conditions at sea,” explains lead author Efrem Maconi in a press release. “Our Sun encountered a region of higher gas density as it passed through the Radcliffe Wave in the Orion constellation.”

The researchers used data from the ESA’s Gaia mission, along with spectroscopic observations, to accurately determine when the Solar System passed through the RW. By tracing the movement of 56 open clusters in the RW, the researchers traced the motion of the RW and compared it with the Solar System’s movement. Their work shows that the two intersected from 18.2 to 11.5 Myr ago. The closest approach occurred between 14.8 and 12.4 Myr ago.

This figure from the study shows an overview of the Radcliffe wave and selected clusters in a heliocentric Galactic Cartesian frame. The Sun is placed at the center, and its position is marked with a golden-yellow ?. The red dots denote the molecular clouds and tenuous gas bridge connections that constitute the Radcliffe wave. The blue points represent the 56 open clusters associated with the region of the Radcliffe wave that is relevant to this study. The size of the circles is proportional to the number of stars in the clusters. Image Credit: Maconi et al. 2025.

This period of time coincides with the MMD. “Notably, this period coincides with the Middle Miocene climate transition on Earth, providing an interdisciplinary link with paleoclimatology,” the authors write. The correlation is striking, and the researchers say that the influx of interstellar dust shifted Earth’s climate.

“This discovery builds upon our previous work identifying the Radcliffe Wave,” says João Alves, professor of astrophysics at the University of Vienna and co-author of the study. Alves was the lead author of the 2020 paper presenting the discovery of the RW.

“Remarkably, we find that the past trajectories of the Solar System closely approached (dSun–cloud within 50 pc) certain selected clusters while they were in their cloud phase, hinting at a probable encounter between the Sun and the gaseous component of the Radcliffe wave,” the researchers write in their paper.

“We passed through the Orion region as well-known star clusters like NGC 1977, NGC 1980, and NGC 1981 were forming,” Alves said in the press release. “This region is easily visible in the winter sky in the Northern Hemisphere and summer in the Southern Hemisphere. Look for the Orion constellation and the Orion Nebula (Messier 42)—our solar system came from that direction!”

This image shows the well-known Orion Nebula in the center and the less well-known NGC 1977 (The Running Man Nebula) on the left. NGC 1977 was still forming when the Solar System passed through this region about 14 million years ago. Image Credit: By Chuck Ayoub – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=57079507

The increased dust that reached Earth during its passage through the RW could have had several effects. The interstellar medium (ISM) contains radioisotopes like 60Fe from supernova explosions, which could have created anomalies in Earth’s geological record. “While current technology may not be sensitive enough to detect these traces, future detectors could make it possible,” Alves suggests.

More critically, the dust could’ve created global cooling.

A 2005 paper showed that Earth passes through a dense giant molecular cloud (GMC) approximately every 100 million years. “Here we show that dramatic climate change can be caused by interstellar dust
accumulating in Earth’s atmosphere during the Solar System’s immersion into a dense GMC,” those researchers wrote. They explained at the time that there was no evidence linking these passages with severe glaciations in Earth’s history.

This new research from Maconi et al. is shedding some light on the issue.

“While the underlying processes responsible for the Middle Miocene Climate Transition are not entirely identified, the available reconstructions suggest that a long-term decrease in the atmospheric greenhouse gas carbon dioxide concentration is the most likely explanation, although large uncertainties exist,” Maconi said.

This figure shows when the Solar System passed through different star-forming clouds in the Radcliffe Wave. Image Credit: Maconi et al. 2025.

“However, our study highlights that interstellar dust related to the crossing of the Radcliffe Wave might have impacted Earth’s climate and potentially played a role during this climate transition. To alter the Earth’s climate the amount of extraterrestrial dust on Earth would need to be much bigger than what the data so far suggest,” says Maconi. “Future research will explore the significance of this contribution.”

With more research to come in the future, there’s most likely more to the story. In any case, one conclusion seems clear: the Earth passed through a region of dense gas that fits in with the Middle Miocene Disruption.

Research like this, when shallowly read, becomes cannon fodder in the tiresome debate about global climate change. The authors are quick to nip that in the bud.

“It’s crucial to note that this past climate transition and current climate change are not comparable since the Middle Miocene Climate Transition unfolded over timescales of several hundred thousand years. In contrast, the current global warming evolution is happening at an unprecedented rate over decades to centuries due to human activity,” Macon said.

Click on the image to explore an interactive tool showing our Solar System’s passage through the Radcliffe Wave. Image Credit: Maconi et al. 2025.

The researchers also point out some weaknesses in their results. “Our results are based on the tracebacks of the orbits of the Solar System and of the clusters associated with the Radcliffe wave. As noted throughout the text, this method requires some approximations due to inherent difficulties in modelling the past structure and evolution of the gas,” they clarify. They explain that their tracebacks should be thought of as a first approximation of their movements.

However, if they’re right, their work draws another fascinating link between our planet, its climate, and life’s struggle to persist with much larger-scale events beyond Earth.

“Notably, our estimated time interval for the Solar System’s potential location within a dense ISM region (about 14.8–12.4 Myr ago for a distance of 20–30 pc from the center of a gas cloud) overlaps with the Middle Miocene climate transition,” the researchers explain. “During this period, the expansion of the Antarctic ice sheet and global cooling marked Earth’s final transition to persistent large-scale continental glaciation in Antarctica.”

“We are inhabitants of the Milky Way,” said Alves. “The European Space Agency’s Gaia Mission has given us the means to trace our recent route in the Milky Way’s interstellar sea, allowing astronomers to compare notes with geologists and paleoclimatologists. It’s very exciting.” In the future, the team led by João Alves plans to study in more detail the Galactic environment encountered by the Sun while sailing through our Galaxy.

• Press Release: The Galactic Journey of our Solar System
• New Research: The Solar System’s passage through the Radcliffe wave during the middle Miocene
• Previous Research: A Galactic-scale gas wave in the solar neighbourhood
• Previous Research: Passing through a giant molecular cloud: ‘‘Snowball’’ glaciations produced by interstellar dust

The post The Solar System is Taking a Fascinating Journey Through the Milky Way appeared first on Universe Today.

Late is better than never for the ‘Blaze Star’ T Coronae Borealis.

It was on track to be the top astronomical event for 2024… and here we are in 2025, still waiting. You might remember around this time last year, when a notice went out that T Coronae Borealis (‘T CrB’) might brighten into naked eye visibility. Well, the bad news is, the ‘Flare Star’ is officially late to the celestial sky show… but the good news is, recent research definitely shows us that something is definitely afoot.

The outburst occurs once every 80 years. First noticed by astronomer John Birmingham in 1866, T Coronae Borealis last brightened in February 1946. That’s 80 years ago, this month. Located about 2,000 light-years distant on the Hercules/Corona Borealis/Serpens Caput constellation junction border, the star spends most of its time below +10th magnitude. Typically during outburst, the star flares and tops out at +2nd magnitude, rivaling the lucida of its host constellation, Alpha Coronae Borealis (Alphecca).

Finding T Corona Borealis in the Sky

We’re fortunate that T CrB currently rises in the east around local midnight. T CrB then rides high in the pre-dawn sky. Late November would be the worst time for the nova to pop, when the Sun lies between us and the star. The situation only improves as early 2025 goes on, and the region moves into the evening sky.

The constellation Corona Borealis and the location of the ‘Blaze Star.’ Credit: Stellarium

The coordinates for T CrB are:

Declination: +25 degrees, 54’ 58”

Right Ascension: 15 Hours 59’ 30”

Looking eastward in early March, two hours after local midnight. Credit: Stellarium Rare Recurrent Novae

T CrB and other recurrent novae are typically part of a two-star system, with a cool red giant star dumping material on a hot white dwarf companion. This accretion builds up to a runaway flash point, and a nova occurs.

A chart of known recurrent novae. Adapted from The Backyard Astronomer’s Deep-Sky Field Guide by David Dickinson.

Two recent notices caught our eye concerning T Coronae Borealis: one titled T CrB on the Verge of an Outburst: H-Alpha Profile Evolution and Accretion Activity and A Sudden Increase of the Accretion Rate of T Coronae Borealis. Both hint that we may soon see some action from the latent flare star.

“My spectral analysis showed a considerable change in the strength of the H-alpha line profile, which could be considered an indicator of the possible eruption of T CrB in the near future. This change posibly resulted from a significant increase in the temperature and accretion rate,” Gesesew Reta (S.N. Bose National Centre for Basic Sciences) told Universe Today. “However, this cannot serve as definitive confirmation of the expected eruption. Novae are inherently unpredictable, and a more detailed analysis, considering broader parameters, is needed for a more accurate prediction.”

An artist’s conception of T Corona Borealis in outburst. Credit: NASA’s Visualization Studio/Adriana Manrique Gutierrez/Scott Wiessinger What to expect in 2025

First, I would manage expectations somewhat; while +2nd magnitude is bright enough to see with the naked eye, it’s not set to be the “Brightest Star…. Ever!” as touted around the web. We get naked eye galactic novae every decade or so, though recurrent novae are a rarity, with only about half a dozen known examples.

Certainly, the familiar ring-shaped northern crown asterism of Corona Borealis will look different for a few weeks, with a new rival star. Certainly, modern astrophysicists and astronomers won’t pass up the chance to study the phenomenon… I would fully expect assets including JWST and Hubble to study the star.

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Variable Star Resources

The American Association of Variable Star Observers (AAVSO) also posted a recent article on current prospects for T CrB… another good quick look for the brightness of flare star is Space Weather, which posts a daily tracker for its magnitude.

Or you could simply step outside every clear March morning, and look up at Corona Borealis with your ‘Mark-1 eyeballs’ and see if anything is amiss. Hey, you might be the very first one to catch the ‘new star’ adorning the Northern Crown, during its current once-in-a-lifetime apparition.

The post Is T Coronae Borealis About to Light Up? appeared first on Universe Today.