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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

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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.

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A planet’s history is told in its ancient rock. Earth’s oldest rocks are in the Canadian Shield, Australia’s Jack Hill, the Greenstone Belts in Greenland, and a handful of other locations. These rocks hold powerful clues to our planet’s history. On Mars, the same holds true.

That’s why NASA’s Perseverance rover is revisiting some of them.

Perseverance is exploring Jezero Crater, an ancient paleolake. Its thick layer of sediments may contain evidence of ancient life on Mars. Every crater has a rim, and Perseverance’s current campaign involves studying the rim. The crater rim is different than the sediments. It’s made of ancient rock uplifted and exposed on the surface by the ancient impact that created Jezero.

On Earth, geologists regularly study rock that has made itself easy to examine by coming up from the deeper crust and presenting itself. The same thing happens on Mars, though impacts do the lifting, not plate tectonics. Perseverance is studying the rocks on the crater rim in its current Crater Rim Campaign. The location it’s exploring is an exposed outcrop named Tablelands.

This image shows Perseverance’s landing ellipse (green circle) and the different regions in the Jezero Crater. The rover is currently exploring the crater rim, shown in purple. Image Credit: NASA/JPL-Caltech/USGS/University of Arizona

One type of rock that can teach us a lot about Mars’ ancient history is serpentine. It’s common on Earth and Mars and forms in the presence of water. Its presence on Mars is some of our strongest evidence that the planet was once wet.

Perseverance sampled Silver Mountain, a rock in the Tablelands. The rover used its abrasion tool on its robotic arm to create a fresh surface it could analyze. That analysis showed Silver Mountain is rich in pyroxene, a type of silicate found in almost every igneous and metamorphic rock. The rover also collected a core.

After that, it visited a rock named Serpentine Lake that showed telltale signs of serpentine. Perseverance used its abrasion tool to clean the rock for a detailed investigation. Serpentine Lake has an intriguing texture, described in a press release as “cookies and cream.” It’s also high in serpentine and other minerals that form in the presence of water.

Perseverance used its Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument to examine the Serpentine Lake rock. The rock shows a high concentration of serpentine, indicating that it was exposed to water for a long time, a hint of Mars’ potential ancient habitability. Its unusual texture also hints at complex geological processes. Image Credit: NASA/JPL-Caltech

After that, Perseverance doubled back to revisit a rock named “Cat Arm Reservoir.”

It was the first rock the rover studied on the canyon rim. The rover analyzed its composition and detected coarse pyroxene and feldspar crystals, indicating an igneous origin. Unfortunately, Perseverance’s sample tube was empty. Sometimes, the rock the rover tries to sample is weak and turns to dust. This is rare, but it did happen during the rover’s very first sampling attempt, and it happened again with Cat Arm Reservoir.

This image from NASA’s Perseverance Location Tracker shows the rover’s convoluted path as it explores the rim of Jezero Crater. Image Credit: NASA/JPL

Perseverance travelled a small distance and tried to collect a core sample from Cat Arm Reservoir again. That attempt also failed. Then the rover chose a different spot nearby named “Green Gardens” and successfully collected a core sample. It’s next to the abrasion patch on Serpentine Lake.

NASA’s Mars Perseverance rover acquired this image of the area in front of it. It shows the Serpentine Lake abrasion patch on the right-hand side of the rock, with the Green Gardens sampling location on the left. The rover used its onboard Front Right Hazard Avoidance Camera A and captured the image on Feb. 16, 2025 (sol 1420, or Martian day 1,420 of the Mars 2020 mission) at the local mean solar time of 16:45:19. Image Credit: NASA/JPL-Caltech

Like the Serpentine Lake rock, Green Garden is also green, which is a characteristic of the mineral serpentine. Serpentine forms in the presence of water when hydrothermal vents alter ultramafic rocks. Scientists are interested in these minerals because their structure and composition can reveal the history of water on Mars. On Earth, serpentine rock also hosts microbial life, so the same may have been true on Mars. Unfortunately, it’s not clear how much evidence of this life can be preserved.

Perseverance’s “Green Garden” core sample was collected on February 17th. Image Credit: NASA/JPL-Caltech

Perseverance will spend some more time exploring the Tablelands outcrop. It may re-examine the Serpentine Lake abrasion patch and analyze the debris from the Green Gardens drilling and coring. This could take a couple of weeks.

Next on its agenda is “Broom Point,” further down the crater rim. Broom Point contains a spectacular formation of layered rock, which is also intriguing to scientists.

Mars’ ancient history is told in its ancient rocks, but it’s impossible to know in advance which rock holds which clues and how everything will fall into place.

We don’t know what Perseverance will discover about Broom Point. But the rock will tell us something. It always does.

• Press Release: Cookies, Cream, and Crumbling Cores
• Press Release: Gardens on Mars? No, Just Rocks!
• Press Release: Assessing Perseverance’s First Sample Attempt
• NASA: Where is Perseverance?

The post Perseverance Takes A Second Look At Some Ancient Rocks appeared first on Universe Today.

Data from the Chinese rover Zhurong is adding to the pile of evidence for oceans on ancient Mars. For a year, this little craft traveled over nearly two kilometers of the Martian surface and made radar scans of buried natural structures that look like ocean shorelines.

Zhurong’s ground-penetrating radar (GPR) looked under the surface to a depth of 80 meters. There, the radar instrument found thick layers of material similar to beach deposits on Earth. The best way to create such formations is by wave action stirring up and depositing sediments along the shore of an ocean. If these findings stand, they’ll provide a deeper look into Mars’s ancient warm, wet past, and the existence of long-gone seas.

Map of Utopia Planitia showing the landing site of the Zhurong rover and four proposed ancient shorelines. The landing site is about 280 kilometers north of and some 500 meters lower in elevation than the northern hypothesized shorelines. In its traverse, Zhurong traveled south from its landing site, toward the ancient shorelines. Courtesy: Hai Liu, Guangzhou University, China Figuring Out Mars Shorelines

“The southern Utopia Planitia, where Zhurong landed on May 15, 2021, is one of the largest impact basins on Mars and has long been hypothesized to have once contained an ancient ocean,” said Hai Liu, a professor with the School of Civil Engineering and Transportation at Guangzhou University and a core member of the science team for the Tianwen-1 mission, which included China’s first Mars rover, Zhurong. “Studying this area provides a unique opportunity to investigate whether large bodies of water ever existed in Mars’ northern lowlands and to understand the planet’s climate history.”

At first, scientists considered lava flows or dunes to explain the structures Zhurong measured. But, their shapes say otherwise. “The structures don’t look like sand dunes. They don’t look like an impact crater. They don’t look like lava flows. That’s when we started thinking about oceans,” said Michael Manga, a University of California, Berkeley, professor of earth and planetary science. He was part of Hai’s team that recently published a paper about Zhurong’s findings. “The orientation of these features are parallel to what the old shoreline would have been. They have both the right orientation and the right slope to support the idea that there was an ocean for a long period of time to accumulate the sand-like beach.”

Digging into the Past

Aside from their meteorological and geological value, the presence of these shoreline structures also implies that Mars’s ancient oceans were ice-free. “To make ripples by waves, you need to have an ice-free lake. Now we’re saying we have an ice-free ocean. And rather than ripples, we’re seeing beaches,” Manga said. That tells us Mars was a warmer world—at least for a while. Rivers could well have flowed across the surface, contributing rocks and sediments along the shorelines. And, of course, there are structures that imply the presence of oceans. On Earth, oceans provide life habitats and there’s no reason to think that Mars oceans couldn’t have done that, too.

“The presence of these deposits requires that a good swath of the planet, at least, was hydrologically active for a prolonged period in order to provide this growing shoreline with water, sediment, and potentially nutrients,” said co-author Benjamin Cardenas, an assistant professor of geosciences at The Pennsylvania State University (Penn State). “Shorelines are great locations to look for evidence of past life. It’s thought that the earliest life on Earth began at locations like this, near the interface of air and shallow water.”

Shoreline Evidence for Changes on Mars

As far back as Viking, scientists had images showing what looked like irregular shorelines and flow features on the surface. Those features implied bodies of water and flowing rivers. Other missions returned images and data showing ponded areas where smaller bodies of water existed. More recent missions returned images of regions scoured and changed by catastrophic floods. The shoreline features imply that oceans existed.

We know today that Mars’s surface no longer hosts bodies of water. In the past, much of it escaped to space along with Mars’ atmosphere. But some water also went underground and remains there as ice deposits. And, some combined with rocks to form new minerals. Other geological features seem to point to the existence of Martian oceans, like the shorelines Zhurong and Viking measured.

Schematic showing how a series of beach deposits would have formed at the Zhurong landing site in the distant past on Mars (left) and how long-term physical and chemical weathering on the planet altered the properties of the rocks and minerals and buried the deposits. Courtesy: Hai Liu, Guangzhou University, China

However, the irregular shape of those shorelines continued to intrigue planetary scientists. That’s because they didn’t exactly look like shorelines like we see along Earth’s oceans, which are level. In 2007, Manga came up with the idea that the shapes of the shorelines were altered by changes in the planet’s rotation. Why did that happen? Blame it on volcanoes in the Tharsis region. Some 4 billion years ago volcanic activity there built up a huge bulge. That eventually messed with the planet’s rotation. “Because the spin axis of Mars has changed, the shape of Mars has changed. And so what used to be flat is no longer flat,” Manga explained.

If the findings hold up, the buried shorelines tell a compelling story of the last days of oceans on Mars. Based on the team’s paper, that water appears to have lasted tens of millions of years. As it disappeared and the climate dried up, wind-blown regolith covered the shorelines that Zhurong measured.

For now, the Zhurong data provides a look into shoreline deposits that are pristine—but buried under the subsurface. “There has been a lot of shoreline work done,” said Cardenas, “but it’s always a challenge to know how the last 3.5 billion years of erosion on Mars might have altered or completely erased evidence of an ocean. But not with these deposits. This is a very unique dataset.”

For More Information

Ancient Beaches Testify to Long-ago Ocean on Mars
Ancient Ocean Coastal Deposits Imaged on Mars

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New information is pushing Asteroid 2024 YR4 off of our front pages. Initial estimates gave it a 2.8% chance of striking Earth in 2032. Now, the European Space Agency says the chance of it striking our planet is down to a paltry 0.001%.

Scientists dislike expressing things in absolute terms because Nature can make fools of us all, so this is as close to zero as it’s likely to get.

2024 YR4 was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Chile a couple of days after Christmas. ATLAS is an early-warning system for smaller asteroids. When it detected the asteroid on December 27th, 2024, it sent out an alert. Follow-up observations indicated the asteroid’s impact probability was greater than 1%, and that triggered our planetary defence response, which at this point consists of a greater effort to understand the rock and its trajectory.

It’s easy to get used to these asteroid warnings. However, it’s a bad idea to ignore the threat they pose. 2024 YR4 is not very large, only between 40 to 90 metres (130 to 300 ft) in diameter. Its small mass doesn’t mean it’s not dangerous. An asteroid that large can cause serious damage in a populated area. Earth has been struck many times in the past, and there are more impacts in its future.

More worryingly, follow-up observations at first showed the asteroid’s impact probability rising. At its highest rating on 18th February, it had a 2.8% chance of striking Earth. The spike of concern was dulled the next day when observations with the ESO’s Very Large Telescope cut that number in half. People unfamiliar with space, Earth, and asteroids have asked why there’s so much uncertainty. The simple answer is that everything in space is moving. The object is also tiny and dark.

The Very Large Telescope is one of the world’s most advanced telescopes and even it could barely see the asteroid, as the GIF below shows.

via GIPHY

In the two months following its detection, the ESA’s Near-Earth Object Coordination Centre—along with other institutions—monitored the asteroid. More data is better data in this case, and observations allowed astronomers to refine its orbit to determine how much of a threat it posed.

2024 YR4 follows an elliptical orbit around the Sun and crosses Earth’s path, making it a near-Earth Object (NEO). It takes almost four years to complete an orbit, and its last perihelion was on 22 November 2024. Its closest approach to Earth was on Christmas, two days before its discovery. At that time, it came to within 830,000 km of Earth. In December 2028, it will make its next closest approach at just more than 8 million km of Earth. Unfortunately, between this April and leading up to the next approach, none of our ground-based telescopes will be able to see it.

One problem in determining the impact threat is that everything in space is moving. Nothing is still. So, each time the asteroid comes near the Earth or the Moon, the gravity from both bodies has a chance of changing 2024 YR4’s orbit. These are called gravitational keyholes, and they complicate efforts to determine its orbit.

This rising and then falling impact probability is an established pattern in asteroid detection and monitoring. At first, there’s more uncertainty, but as astronomers continue to observe it, uncertainty is reduced.

What it boils down to is this: We spotted another small yet potentially dangerous rock with a chance to strike Earth. We watched it and saw that its chance of striking us shrank. Now, the rock will disappear into the blackness of space for three years.

Where does that leave us?

Each time another asteroid approaches, it triggers concern about protecting Earth. Should we launch a nuke and blow it to pieces? How about a kinetic impactor to change its orbit slightly? How about evacuating people from the impact zone?

We’re developing ways to protect the planet. NASA’s DART (Double Asteroid Redirection Test) showed that a relatively small mass can deter an approaching asteroid. Nukes are not needed and, in fact, can create an unpredictable shower of debris.

This artist’s illustration shows the ejection of a cloud of debris after NASA’s DART spacecraft collided with the asteroid Dimorphos. Credit: ESO/M. Kornmesser

One proposal for asteroid redirection envisions kinetic impactors waiting to be launched on short notice. They can be at a Lagrange point or possibly on the lunar surface, on standby until needed. The more advance notice we have, the smaller the kinetic mass needed to deter an asteroid.

The main effort right now is centred on finding all dangerous asteroids and constraining their orbits. The upcoming Vera Rubin Observatory will detect many asteroids and will help us identify which ones are hazardous.

The type of massive asteroid that rocked the dinosaurs is increasingly unlikely. It was between 10 and 15 km in diameter, and large asteroids like it tend to remain stable in the asteroid belt. But the smaller ones in the decameter size range are more likely to be perturbed out of their orbits and become NEOs. It’s those ones we really have to worry about.

NASA’s “Eyes on Asteroids” site maps the known Near-Earth asteroids (NEAs) and shows the population of these objects. Some are parent bodies of meteorites found on Earth. Courtesy NASA.

Asteroids are like pandemics. There’s always another one in the future. It’s simply nature. The danger from this one seems to have diminished, but another one will eventually come close.

Though the danger posed by 2024 YR4 has diminished, the overall threat posed by the asteroid population remains the same. In a sense, it’s not about any individual asteroid. It’s about our understanding of the risks in our space environment and how we can protect ourselves and Earth.

We’re not fully prepared to deflect an incoming asteroid if necessary, but we’re working towards it. In the meantime, get used to the occasional news article about asteroids with tiny yet real chances of striking Earth. 0.001% is tiny, but it’s not zero.

The post As Expected, the Threat from 2024 YR4 has Essentially Dropped to Zero appeared first on Universe Today.

Neutron stars are stellar remnants. Composed of dense nuclear material, they all have strong magnetic fields. But the magnetic fields of some neutron stars can be a thousand times stronger. They are known as magnetars, and we aren’t entirely sure how they generated such powerful magnetic fields. But a new study in Nature Astronomy reveals some clues.

The general thought has been that magnetars create their fields through some type of dynamo process. This is where a flow of magnetic material generates a magnetic field. Since the flow is driven by heat convection, it can power strong fields. Earth’s magnetic field is unusually strong for a planet of its size and is powered by the convection of iron in its core. However, the core of a neutron star is made of nucleons, not atoms, so it is difficult to determine a specific dynamo process for magnetars.

For this study, the team wanted to understand what are known as low-field magnetars. These are magnetars that have weaker magnetic fields than most magnetars, but still generate bursts of X-rays and gamma rays. Most magnetars are identified by their high-energy emissions, since it takes intense magnetic fields to create such powerful bursts. Low-field magnetars shouldn’t have a strong enough field to create such bursts, but they sometimes do. This would suggest that at times their magnetic fields become intense. The question is how.

To answer this question, the team ran computer simulations of several dynamo models, looking for one that best fit the observational data. They found that the best fit involved what’s known as the Tayler–Spruit dynamo. This dynamo is well known in stellar models and involves the differential rotation of a stellar core. Stars don’t rotate as a single rigid object. Instead, different latitudes of a star rotate at slightly different rates. This is likely caused by a fast-rotating core, which can produce the Tayler–Spruit dynamo.

The authors demonstrated that as a low-field magnetar forms, the supernova that created the magnetar transfers angular momentum to its core, thus creating a differential rotation. Through the Tayler–Spruit dynamo, this can create bursts of intense magnetic fields that power the X-rays and gamma rays we observe from these stars. This process is likely unique for low-field magnetars, as opposed to traditional magnetars that generate their magnetic fields in other ways.

Reference: Igoshev, Andrei, et al. “A connection between proto-neutron-star Tayler–Spruit dynamos and low-field magnetars.” Nature Astronomy (2025): 1-11.

The post So This is How You Get Magnetars appeared first on Universe Today.

Well that’s ruined all my lectures! I’ve spent years talking about space and a go to fact is the red colour of Mars. It’s been long believed that it was caused by the same chemical process that creates rust on Earth, a new paper suggests this is not the case! The team of researchers simulated conditions of Mars in a lab and now think a chemical called ferrihydrite, an iron oxide that contains water. It now looks like the planet’s characteristic red colour is due to a time when Mars was covered in water! 

Mars, often called the Red Planet is the fourth planet from the Sun. With a thin atmosphere composed mostly of carbon dioxide, Mars features a stark landscape of vast plains, huge volcanoes including Olympus Mons (the largest in our solar system), and deep canyons like Valles Marineris. Its surface has evidence of ancient rivers and lakes, suggesting Mars once had conditions that could have been suitable for microbial life. Its extreme temperature changes and frequent global dust storms are typical of this harsh world. 

Mars seen before, left, and during, right, a global dust storm in 2001. Credit: NASA/JPL/MSSS

The distinctive red colour goes back centuries; the ancient Egyptians called Mars ‘Her Desher’ which translates to ‘the Red One’, the Romans named it after the God of war and the Chinese called it ‘the fire star.’ Even Babylonian records that go back to 2000 BC noted its red colour. In 1610, when Galileo first observed Mars through a telescope, he confirmed its planetary nature but also noted a more red/brown hue. This was largely due to the poor quality optics of the day and it wasn’t until optics improved that its red colour was observed in all its glory.

A bust of Galileo at the Galileo Museum in Florence, Italy. The museum is displaying recovered parts of his body. Credit Kathryn Cook for The New York Times

A team of researchers led by Dr Adomas Valantinas from Brown University in USA have published a paper in Nature Communications that has analysed the red colouration of Mars and challenge the common view that it’s a rust like material that is responsible. They used data from a number of different Mars missions from NASA’s Reconnaissance Orbiter to ESA’s Mars Express and ExoMars (which has the Colour and Stereo Surface Imaging System onboard.) The data from the orbiters was supported by data from various rovers too and further supplemented by analysis of artificial Mars-like materials in a laboratory.

An artist’s illustration of the Mars Express Orbiter above Mars. Its MARSIS instrument has been updated so it can study the moon Phobos. Image Credit: Spacecraft: ESA/ATG medialab; Mars: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

The analysis, which included experiments and measurements at the University of Grenoble, Brown University and the University of Winnipeg revealed the presence of Ferrihydrite. Not only was it present in the Martian dust, it seemed to be widespread across the Martian landscape. Ferriydrite is an oxyhydroxide mineral (one that contains oxygen, hydrogen and at least one metal.)

The widespread discovery of ferrihydrite on in Martian dust helps us to understand more about the geological history of Mars and its potential habitability. The existence of the ferrihydrite tells us that there were once cooler, wet conditions on Mars since that is a neccessity for the formation of the mineral. It’s an exciting discovery because its one more reason to believe that Mars was once a hospitable world. 

The team are keen to learn more and are now waiting for Martian samples to study directly and for that, they are waiting for the Perseverance rover. It has been systematically collecting core samples of Martian soil from the Jezero Crater and storing them in titanium tubes ready for transport home. Once the team has these, they will be able to check whether their theory about ferrihydrite is correct.

Source : Why Mars could be red

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According to Darwin, life on Earth may have first appeared in warm little ponds. This simple idea is also a cornerstone in our search for the origin of life. The ponds were rich in important chemicals, and when lightning struck, somehow, it all got going.

If the idea is correct, the same thing may have happened on Mars. If it did, and if fossilized evidence of microbes on the planet exists, a new laser could find it.

We may never know exactly how life started. It appeared to start about 4 billion years ago on Earth, confined to water for about 3 billion, until our planet developed a UV-blocking ozone layer.

If life ever appeared on Mars, it also likely occurred billions of years ago when the planet was warm and wet. There’s a strong possibility that it was also confined to water for a long time. If it did, then ancient sediments could hold fossilized evidence of microbes.

NASA’s Perseverance rover landed in Jezero Crater, an ancient paleolake with deep sediments, in an attempt to detect evidence of ancient life. Jezero also contains an ancient river delta, an excellent place for sediments to collect and potentially preserve microbial evidence.

Perseverance carries a laser as part of its Supercam instrument, an improved version of MSL Curiosity’s Chemcam instrument and laser. Supercam analyzes rocks and soils and searches for organic compounds that are biosignatures of ancient microbial life.

Now, scientists are working on a new laser that could detect microbial fossils on Mars. The device will examine gypsum deposits for signs of these fossils. The device has already been tested in Mars-analogue gypsum deposits in Algeria.

The method is explained in new research published in Frontiers in Astronomy and Space Sciences. Its title is “The search for ancient life on Mars using morphological and mass spectrometric analysis: an analog study in detecting microfossils in Messinian gypsum.” The lead author is Youcef Sellam, a PhD student at the Physics Institute at the University of Bern.

“Our findings provide a methodological framework for detecting biosignatures in Martian sulfate minerals, potentially guiding future Mars exploration missions,” said Sellam. “Our laser ablation ionization mass spectrometer, a spaceflight-prototype instrument, can effectively detect biosignatures in sulfate minerals. This technology could be integrated into future Mars rovers or landers for in-situ analysis.”

Sellam is referring to sulphate minerals, including gypsum, left behind when bodies of water dry up. The minerals precipitate out and collect as deposits, as has happened repeatedly in the Mediterranean Sea during the Messinian salinity crisis.

“The Messinian Salinity Crisis occurred when the Mediterranean Sea was cut off from the Atlantic Ocean,” said Sellam. “This led to rapid evaporation, causing the sea to become hypersaline and depositing thick layers of evaporites, including gypsum. These deposits provide an excellent terrestrial analog for Martian sulfate deposits.”

We know something similar happened on Mars because gypsum deposits are plentiful. Since these deposits form rapidly, there’s a chance for fossils to be preserved before they can decompose.

“Gypsum has been widely detected on the Martian surface and is known for its exceptional fossilization potential,” explained Sellam. “It forms rapidly, trapping microorganisms before decomposition occurs, and preserves biological structures and chemical biosignatures.”

Gypsum deposits on Earth have been extensively studied for evidence of microbes.

These images, taken from separate research into gypsum deposits on Earth, show different types of microbial colonization in gypsum deposits. Panels B and C, for example, show zones rich in algal cells. More info here. Image Credit: Jehlicka et al. 2025.

“Prokaryotic communities are often found dwelling within modern evaporites, such as gypsum, forming in sabkhas, lacustrine, and marine terrestrial sediments,” the authors explain in their paper. “They mainly participate in carbon, iron, sulphur, and phosphate biogeochemical cycles, extracting water and using various survival strategies to avoid ecological stresses. Consequently, investigating these fossil filaments may enhance our comprehension of the cryptic conditions that led to the formation of the Primary Lower Gypsum unit during the Messinian Salinity Crisis, the biosignature preservation potential of gypsum, and the possible preservation of such fossils in ancient, hydrated sulphate deposits on Mars.”

Detecting evidence in Earth’s gypsum deposits is relatively simple. However, doing it on Mars is rife with challenges. Since scientists already know that Mediterranean gypsum deposits hold evidence of life, Sellam went to test the method there.

Sellam and his co-researchers tested their method at the Sidi Boutbal (SB) quarry in the Lower Chelif basin in Algeria. “The Chelif Basin is one of the largest Messinian peripheral sub-basins, characterized by an elongated and ENE–WSW oriented structure spanning over 260 km in length and 35 km in width,” the authors explain in their paper. The quarry contains gypsum deposits that are tens of meters thick.

These figures from the research show gypsum deposits in the Mediterranean, including the Sidi Boutbal quarry in Algeria, where the researchers tested their method. The black stars in C, D, and E show the sampled gypsum unit. Image Credit: Sellam et al. 2025.

The researchers used several methods in their work, including optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and spatially resolved laser ablation mass spectrometry (LIMS). These aren’t new technologies, but combining them into an instrument that can be carried by a rover is new.

In their tests in Algeria, the researchers used a miniature laser-powered mass spectrometer, which can analyze the chemical composition of a sample in detail as fine as a micrometre. They also sampled gypsum and analyzed it using the mass spectrometer and an optical microscope. Many natural rock formations can mimic microbial fossils, so they followed criteria to distinguish between potential microbial fossils and natural rock formations. Microbial fossils display morphology which is irregular, sinuous, and potentially hollow.

In their paper, the authors report finding “a densely interwoven network of brownish, sinuous, and curved fossil filaments of various sizes.”

A is an optical microscope image of permineralized filamentous microfossils, and G is a scanning electron microscope of the same microfossils. Image Credit: Sellam et al. 2025.

Their method also detects the presence of chemical elements necessary for life, carbonaceous material, and minerals like clay or dolomite, which can be influenced by the presence of bacteria. “The inner layer of the filament is morphologically and compositionally distinct from the gypsum, mainly composed of Ca, S, O, and traces of Si,” the authors write.

This is a Scanning Electron Microscope and Energy Dispersive X-ray (SEM-EDX) spectrum of the same area. Red shows the predominant mineral, blue shows clay minerals, and yellow shows the inner layer of the fossil filaments. Image Credit: Sellam et al. 2025.

The authors found not only fossil filaments, but also dolomite, clay minerals, and pyrite surrounding the gypsum they were embedded in. This is important because their presence signals the presence of organic life. Prokaryotes supply elements that clays need to form and also help dolomite form, which often forms in the presence of gypsum. The only way that dolomite can form without life present is under high pressures and temperatures. To scientists’ knowledge, those conditions weren’t present on early Mars.

This is interesting progress, but there’s still lots of work to do.

It starts with identifying clay and dolomite in Martian gypsum. Along with other biosignatures, this indicates that fossilized life is there. If the system can identify other chemical minerals, that would help, too. Ultimately, finding organically formed filaments at the same time would be solid evidence that the planet once supported life.

“While our findings strongly support the biogenicity of the fossil filament in gypsum, distinguishing true biosignatures from abiotic mineral formations remains a challenge,” cautioned Sellam. “An additional independent detection method would improve the confidence in life detection. Additionally, Mars has unique environmental conditions, which could affect biosignature preservation over geological periods. Further studies are needed.”

If this method proves to be reliable, it’ll have to wait a while before being implemented.

The ESA’s Rosalind Franklin rover will launch to Mars in 2028. It will look for subsurface chemical and morphological evidence of life. Its instruments have already been chosen. Other nations and agencies have missions to Mars in the planning and proposal stages, but none of them are full-featured rovers like Curiosity and Perseverance.

However, another rover mission to Mars in the future is almost a certainty. Maybe this technology will be ready to go by then.

“Although the Messinian Salinity Crisis, during which the Primary Lower Gypsum formed, remains only partially understood, future astrobiological investigations on Mars should consider hydrated sulphate deposits as promising indicators of ancient Martian environmental conditions. This contribution underscores that hydrated sulphates serve as archives of biological history on Earth and potentially on Mars, should evidence of past life be found,” the authors conclude.

• Press Release: Laser-powered device tested on Earth could help us detect microbial fossils on Mars
• Published Research: The search for ancient life on Mars using morphological and mass spectrometric analysis: an analog study in detecting microfossils in Messinian gypsum

The post This Laser Could Find Fossil Microbes on Mars appeared first on Universe Today.

The habitable zone of a planetary system is based on a simple idea: if a planet is too close to its star then conditions are too hot for life, and if a planet is too distant then things are too cold. It’s broadly based on the estimated temperature/distance range for liquid water to exist on a planet’s surface, since life as we know it needs liquid water to exist. The problem with this definition is that it’s too crude to be very useful. For example, both Venus and Mars are at the inner and outer edges of the Sun’s habitable zone, but neither are really habitable. But now that we have observed hundreds of planetary systems, we can start to pin down the zone more accurately. One way to do this is to look at sulfur chemistry.

A new paper in Science Advances looks at how sulfur chemistry can better define the inner border of a star’s habitable zone. The authors note that the key is whether a planet can maintain a surface ocean. Many inner planets are warm enough to have liquid oceans early on but lose those oceans over time. Venus is a good example of this. Early Venus was likely very Earth-like, but the lack of a strong magnetic field and water-rich volcanic activity meant Venus’s early oceans boiled away.

Even from light-years away, the difference between Venus and Earth is striking. If alien astronomers were to observe the atmospheres of both, they would see that Earth has a mix of nitrogen and oxygen, while Venus has a mostly carbon dioxide atmosphere rich in sulfur dioxide. From this, they would know that Earth has oceans while Venus does not. Both planets have plenty of sulfur, but Earth’s oceans prevent large amounts of sulfur dioxide from forming. It takes dry surface chemistry to create sulfur dioxide.

The authors show how the presence of atmospheric sulfur is a marker for an oceanless planet. For sunlike stars, this could be used to narrow the habitable zone and select better candidates for alien life. If an inner planet has a sulfur-rich atmosphere, there’s no need to look further. There is, however, a catch.

While dry, warm planets would tend to generate plenty of sulfur compounds, ultraviolet light tends to break these molecules up. So, the team demonstrates, while the presence of atmospheric sulfur proves a planet is dry, the opposite is not always true. A dry planet orbiting a high-UV star would also lack sulfur compounds. To demonstrate this, the team looked at the red dwarf system TRAPPIST-1, which has at least three potentially habitable planets. They found that the UV levels for these worlds are too high to use the sulfur test. This is a real bummer, since red dwarf planets are the most common home for potentially habitable worlds, and most of those planets are bathed in much more UV than Earth since they orbit their star so closely.

So this study shows that sulfur chemistry is a useful tool for finding life, though not as useful as we’d like. It will take more chemical identifiers to narrow down the habitable zones for red dwarfs.

Reference: Jordan, Sean, Oliver Shorttle, and Paul B. Rimmer. “Tracing the inner edge of the habitable zone with sulfur chemistry.” Science Advances 11.5 (2025): eadp8105.

The post Can We Develop a More Accurate Habitable Zone Using Sulfur? appeared first on Universe Today.

Air travel produces around 2.5% of all global CO2 emissions, and despite decades of effort in developing alternative fuels or more efficient aircraft designs, that number hasn’t budged much. However, NASA, also the US’s Aeronautics administration, has kept plugging away at trying to build a more sustainable future for air travel. Recently, they supported another step in that direction by providing an Institute for Advanced Concepts (NIAC) grant to Phillip Ansell of the University of Illinois Urbana-Champaign to develop a hybrid hydrogen-based aircraft engine.

The grant focuses on developing the Hydrogen Hybrid Power for Aviation Sustainable Systems (Hy2PASS) engine, a hybrid engine that uses a fuel cell and a gas turbine to power an aircraft. Hybrid systems have been tried before, but Hy2PASS’s secret sauce is its use of air handling.

In hybrid aircraft systems, there’s typically a fuel cell and a gas turbine. The fuel cell takes hydrogen as an input and creates electrical energy as output. In a typical hybrid system, this electrical energy would power a compressor, whose output was directly coupled to turning the turbine. However, in Hy2PASS, the compressor itself is decoupled from the turbine, though it still supplies oxygen to it. It then also supplies oxygen to the fuel cell’s cathode, allowing for its continued operation.

AI generated video on the Hy2PASS system.

This method has a few advantages, but the most significant one is the dramatic increase in efficiency it allows. The waste heat created at that mechanical connection is eliminated by uncoupling the compressor directly from the turbine. Also, it allows the compressor to be run at different pressures, allowing an algorithm to optimize its speed while ignoring the necessary speed of the turbine.

Additionally, the emissions from the entire system are essentially just water. So, this hybrid system effectively eliminates the emissions created by this kind of hybrid engine altogether. So, in theory, at least, this type of propulsion system would be the holy grail that NASA and the rest of the aviation industry have been seeking for years.

There’s still a long way to go to make this system a reality. The Phase I NIAC grant will focus on proving the system’s concept. Importantly, it will also require an understanding of another aircraft system and “mission trajectory optimization” to minimize the energy requirements of any future use case for the system. That sounds like there would be some limitations for how the system might be used in practice, though fleshing that out as part of Phase I seems a reasonable use case.

Interview with Dr. Ansell, the PI on the Hy2PASS project.

If the project is successful, and given Dr. Ansell’s track record of consistently meeting NASA design objectives, that seems a good bet. It is possible that someday soon, a hydrogen-powered aircraft could be in the air again. And this time, it will be a key player in eliminating emissions from one of the most important industries in the world.

Learn More:
NASA – Hydrogen Hybrid Power for Aviation Sustainable Systems (Hy2PASS)
UT – Multimode Propulsion Could Revolutionize How We Launch Things to Space
UT – Reaction Engines Goes Into Bankruptcy, Taking the Hypersonic SABRE Engine With it
UT – NASA is Working on Electric Airplanes

Lead Image:
Artist’s concept of the Hy2PASS engine
Credit – NASA / Phillip Ansell

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Researchers study enigmatic asteroid Kamo’oalewa, as China’s first asteroid sample return mission moves toward launch.

China is about to get in to the asteroid sample return game. The CNSA (China National Space Administration) has recently announced that its Tianwen-2 mission has arrived at the Xichang Space Center. The mission will launch this May, on a Long March 3B rocket with the agency’s first solar system exploration mission of the year.

The mission was originally named ZhengHe, after a 15th century explorer. Tianwen-2 is a follow-on to China’s Tianwen-1, the nation’s first successful Mars orbiter-lander mission. Set to launch this coming May, Tianwen-2 will perform an ambitious first: not only will it explore asteroid 469219 Kamo’oalewa, but it will head onward to Comet 311P/PanSTARRS, in a first-ever asteroid-comet exploration mission for the agency.

A Tantalizing Worldlet

Certainly, asteroid Kamo’oalewa is an intriguing space rock. An Apollo Group Near Earth Asteroid, Kamo’oalewa is a rare quasi-satellite of the Earth. Discovered on the night of April 27th, 2016 from the Haleakala Observatory, the asteroid received the provisional designation 2016 HO3. The formal name means ‘oscillating fragment’ in the Hawaiian language. The asteroid currently fluctuates from being a quasi-satellite and horseshoe orbit between the Sun-Earth L1-L2 and L4-L5 Lagrange points, respectively. One day—perhaps a 100 million of years or so in the future—Kamo’oalewa may ultimately strike the Earth or the Moon.

A reddish object, Kamo’oalewa is either an S- or L-type asteroid, about 40 to 100-meters in size. The asteroid also bears a striking spectral resemblance to Apollo 14 and Luna 24 soil returns, suggesting it may in fact be ejecta from the impact that formed the Giordano Bruno crater on the Moon. The farside crater is thought to be about 4 million years old.

Giordano Bruno crater on the lunar farside. Credit: NASA/LRO Following Asteroid Kamo’alewa

A recent study out of the European Space Agency’s Near-Earth Objects Coordination Centre (NEOCC) entitled Astrometry, Orbit Determination and Thermal Inertia of the Tianwen-2 Target Asteroid (469219) Kamo’oalewa is looking to better understand the tiny world ahead of the mission’s arrival. Specifically, the study looks to refine the orbit of the asteroid, and understand how the Yarkovsky and YORP (Yarkovsky-O’Keefe-Radzievskii-Paddack) effects act on the orbit and rotation of the asteroid over time. The Yarovsky Effect is the result of how sunlight alters the path of small asteroids over time, as they absorb solar energy and re-emit it as heat. YORP is a similar phenomena, but includes the scattering of sunlight due to the shape and surface structure of the asteroid. Kamo’oalewa is a fast rotator, spinning on its axis once every 27 minutes. This will add to the challenge of grabbing a sample.

“We observed Kamo’oalewa and precisely measured its position in the sky,” lead researcher on the study Marco Fenucci (ESA/ESRIN/NEO Coordination Centre) told Universe Today. “Thanks to these new measurements, we were able to determine the Yarkovsky effect with a signal-to-noise ratio of 14, and the overall accuracy of the orbit was improved.”

Our best view yet of asteroid Kamo’oalewa. Credit: ESA/NEOCC/Loiano Astronomical Station

The study used current observations from the Calar Alto Observatory in Spain and Loiano Astronomical Station based in Italy, as well as pre-discovery observations found in the Sloan Digital Sky Survey (SDSS) from 2004. These were especially challenging for the team to incorporate, as SDSS used a unique drift scan method to complete images. Also, an NEO asteroid like Kamo’oalewa has a relatively fast proper motion against the starry background. These two factors presented a challenge to pinning the asteroid’s time and location down in earlier images.

An Enigmatic World

“Thanks to the accurate measurement of the Yarkovsky effect on Kamo’oalewa, we were able to estimate the surface thermal inertia,” says Fenucci. “Our best estimate indicates that the thermal inertia is smaller than that of Bennu and Ryugu (the target for JAXA’s Hayabusa2 mission). A low value of thermal inertia is usually due to the presence of regolith on the surface of the asteroid. The presence of regolith was not expected on such fast rotators.”

Certainly, the tiny world is worthy of further scrutiny. Any information will be handy leading up the Tianwen-2’s arrival. Like NASA’s OSIRIS-REx, which sampled asteroid 101955 Bennu in 2020, Tianwen-2 will use a touch-and-go sample technique, in addition to an anchor-and-attach method to acquire its samples of asteroid Kamo’oalewa.

“Kamo’oalewa will be the smallest asteroid visited by a spacecraft, and also the one with the shortest rotation period,” says Fenucci. “In terms of composition, the spectrum is similar to that of S-type asteroids, for example, Itokawa or Eros.” The reddish aspect of the asteroid in the visible-to-near infrared part of the spectrum, however, remains a mystery. “This is a typical feature of lunar regolith,” says Fenucci. “However, this particular feature can also be caused by space weathering. The Tianwen-2 mission should give an answer to the question of the origin of Kamo’oalewa.”

Tianwen-2 Mission Timeline

Currently rendezvous with the asteroid is set for 2026, with a departure in 2027. The CNSA team hopes to nab about 100 grams of Kamo’oalewa, about the mass of medium-sized apple. After that, the mission will dispatch its return capsule on Earth flyby in late 2027. Then, it will head onward to explore periodic comet 311/P PanSTARRS. The mission will reach the comet in 2034.

The Tianwen-2 spacecraft to carry out a sample-return targeting near-Earth asteroid 469219 Kamo?oalewa has arrived at Xichang spaceport. Launch date not revealed, but expected around May. english.news.cn/20250220/d95…

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— Andrew Jones (@andrewjonesspace.bsky.social) February 20, 2025 at 6:08 AM

China has certainly taken a prudent, incremental path to space exploration. CNSA’s Chang’e program has returned samples of the lunar near and far side. Tianwen-1 was successful at Mars, scoring a combination orbiter, lander and rover on the Red Planet, all in one mission. China also has long term plans to combine these proven techniques in a Mars sample return mission of their own. This could launch as early as 2028.

It will be exciting to see asteroid Kamo’oalewa up close, as Tianwen-2 attempts to unravel the origin story for this elusive world.

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