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Scientists have developed new light-sensitive chemicals that can radically improve the treatment of aggressive cancers with minimal side effects. In mouse tests, the new therapy completely eradicated metastatic breast cancer tumors.

Scientists have developed new light-sensitive chemicals that can radically improve the treatment of aggressive cancers with minimal side effects. In mouse tests, the new therapy completely eradicated metastatic breast cancer tumors.

Combustion engines, the engines in gas-powered cars, only use a quarter of the fuel's potential energy while the rest is lost as heat through exhaust. Now, a study demonstrates how to convert exhaust heat into electricity. The researchers present a prototype thermoelectric generator system that could reduce fuel consumption and carbon dioxide emissions -- an opportunity for improving sustainable energy initiatives in a rapidly changing world.

Surveys before, early on in and towards the end of the covid-19 pandemic suggest that although older people's well-being dipped in 2020, it increased once virus-related restrictions in England were lifted

We have the transit method to thank for the large majority of the exoplanets we’ve discovered. When an exoplanet transits its star, the dip in starlight tells astronomers that a planet is present. Analyzing the light can tell them about the planet’s size and atmospheric properties. However, a star’s surface isn’t always uniformly heated. There can be hotter, brighter spots and colder, dimmer spots that change over time.

New research says these temperamental stars are distorting our understanding of exoplanets.

The number of confirmed exoplanets is approaching 6,000. Astronomers want to understand these planets better in all their bewildering variety. The only way to do that is to examine light and how it changes in exquisite detail. When an exoplanet transits in front of its host star, astronomers can ‘read’ the starlight as it passes through the planet’s atmosphere.

However, new research shows that the stars that host all these planets can pollute the light signal from their orbiting planets, giving us a distorted view of their sizes, temperatures, and atmospheres.

The research is “A Population Analysis of 20 Exoplanets Observed from Optical to Near-infrared Wavelengths with the Hubble Space Telescope: Evidence for Widespread Stellar Contamination,” and it’s published in The Astrophysical Journal Supplement Series. The lead author is Arianna Saba from the Department of Physics and Astronomy at University College London.

A star’s surface is defined in large part by its temperature, which is influenced by the star’s powerful magnetic fields. Magnetic fields can inhibit the heat flow from a star’s interior to its surface, creating a cooler, dimmer region. Conversely, it can channel more heat into other areas, creating brighter regions.

This extraordinarily detailed image of the Sun’s surface comes from the Solar Orbiter during a recent close encounter. Swirling magnetic fields help create cooler and hotter regions on the surface. Image Credit: ESA – European Space Agency

“Some stars might be described as ‘patchy’ – they have a greater proportion of colder regions, which are darker, and hotter regions, which are brighter, on their surface. This is due to stronger magnetic activity,” said study co-author Alexandra Thompson.

“Hotter, brighter regions (faculae) emit more light, and so, for instance, if a planet passes in front of the hottest part of the star, this might lead researchers to over-estimate how large the planet is, as it will seem to block out more of the star’s light, or they might infer the planet is hotter than it is or has a denser atmosphere,” Thompson explained. “The reverse is true if the planet passes in front of a cold starspot, making the planet appear ‘smaller.’

These temperamental stars can also produce false positives.

“On the other hand, the reduction in emitted light from a starspot could even mimic the effect of a planet passing in front of a star, leading you to think there might be a planet when there is none. This is why follow up observations are so important to confirm exoplanet detections,” said Thompson.

This image shows our Sun during a period of high activity, with multiple hot spots and cool spots. Image Credit: NASA/Goddard Space Flight Center

The question is, how much of our understanding of these exoplanets is polluted by these patchy stars? Is stellar contamination creating a bias in our understanding of the exoplanet population?

To find out, Saba and her co-researchers examined the archival data from 20 exoplanet atmospheres previously observed with the Hubble’s Space Telescope Imaging Spectrograph (STIS) and Wide Field Camera 3 (WFC3) instruments. These workhorse instruments “see” in UV, infrared, and visible light. They wanted to know if observations taken with the same instruments at different times produced different results and if any differences were confined to observations in specific wavelengths.

“To obtain spectral information from the near-ultraviolet to the near-infrared, we reanalyzed 16 WFC3 and over 50 STIS archival data sets with our dedicated HST pipeline,” the authors write in their paper. “Across our target sample, we observe significant divergence among multiple observations conducted with the same STIS grating at various epochs, while we do not detect variations in the WFC3 data sets.”

This suggested that stellar contamination is an issue, but the researchers dug deeper to understand how. Using Bayesian tools and other analytic models, they found that stellar activity had contaminated about half of the exoplanet atmospheres in their sample to varying degrees. Six of the exoplanets had pronounced contamination, and six others had lesser degrees of contamination.

“These results were a surprise – we found more stellar contamination of our data than we were expecting,” said lead author Saba. “This is important for us to know. By refining our understanding of how stars’ variability might affect our interpretations of exoplanets, we can improve our models and make smarter use of the much bigger datasets to come from missions including James Webb, Ariel and Twinkle.” Twinkle is a low-cost mission that will study exoplanet atmospheres from Low-Earth Orbit.

This figure from the paper illustrates some of the divergent results from observing exoplanets in different epochs. There was significantly more divergence among STIS observations than among WFC observations. STIS G430 and G750L are different gratings, and G102 and G141 are different WFC grisms. Image Credit: Saba et al. 2025.

Stellar contamination of exoplanet observations is no small matter. It can skew results in very pronounced ways. “Accounting for stellar activity can significantly alter planetary atmospheric parameters like molecular abundances (up to 6 orders of magnitude) and temperature (up to 145%), contrasting with the results of analyses that neglect activity,” the authors write in their paper.

According to the researchers, there are two ways to determine if stellar variability is affecting exoplanet data.

“One is to look at the overall shape of the spectrum – that is, the pattern of light at different wavelengths that has passed through the planet from the star – to see if this can be explained by the planet alone or if stellar activity is needed,” said Saba. “The other is to have two observations of the same planet in the optical region of the spectrum that are taken at different times. If these observations are very different, the likely explanation is variable stellar activity.”

One of the key findings concerns optical and UV observations. Since stellar activity is much more visible in optical and UV, exoplanet observations based on these wavelengths are more likely to reveal the contamination. Conversely, IR observations may overlook the contamination.

“Our results emphasize the importance of considering the effects of stellar contamination in exoplanet transit studies; this issue is particularly true for data sets obtained with facilities that do not cover the optical and/or UV spectral range where the activity is expected to be more impactful but also more easily detectable,” the paper states.

“The risk of misinterpretation is manageable with the right wavelength coverage,” said Thompson. “Shorter wavelength, optical observations such as those used in this study are particularly helpful, as this is where stellar contamination effects are most apparent.”

This issue clearly needs more investigating, and the researchers say they’ve identified stars that need more follow-up. They also explain that previous exoplanet atmosphere studies should be revisited, especially ones that lacked broad optical or UV coverage. By the same token, future exoplanet atmospheric studies should be multi-wavelength.

According to the authors, the active stars identified in this research should also be studied more thoroughly. This will increase astronomers’ understanding of how they influence observations of exoplanet atmospheres. Better models and analytic tools are also needed.

We’re still in the very early days of examining exoplanet atmospheres, so these results aren’t exactly surprising. The JWST is probing some exoplanet atmospheres, and future missions like the ESA’s ARIEL (Atmospheric Remote-Sensing Infrared Exoplanet Large survey) will do the same. ARIEL will perform the first large-scale survey of the chemistry of exoplanet atmospheres, highlighting the significance of these results.

“Our findings demonstrate the significant role that stellar contamination may have in all exoplanet spectra observations,” the authors write in their conclusion. “Therefore, comprehending, modeling, and correcting for the impact of stellar activity is important for a complete characterization of exoplanet atmospheres.”

The post Temperamental Stars are Messing With Our Exoplanet Efforts appeared first on Universe Today.

Critics have been calling for NASA to cancel its extremely pricey Space Launch System rocket for ages, but now that it seems to be facing the axe from Elon Musk’s government efficiency task force, it may be time to think again

During the 1970s, while probing distant galaxies to determine their mass, size, and other characteristics, astronomers noticed something interesting. When examining the rate at which these galaxies rotated (their rotational curves), they found that the outer parts were rotating faster than expected. In short, their behavior suggested that they were far more massive than they appeared to be. This led to the theory that in addition to stars, gas, and dust, galaxies were surrounded by a “halo” of mysterious, invisible mass – what came to be known as Dark Matter (DM).

It was famed astronomer Vera C. Rubin, for whom the Vera C. Rubin Observatory (formerly the LSST) is named, who first proposed that DM played an important role in galactic evolution. Astronomers have since theorized that DM haloes must have existed shortly after the Big Bang and were integral to the formation of the first galaxies. In a recent study, an international team examined the core regions of two galaxies that existed 13 billion years ago. Their observations confirmed that DM dominated the haloes of these quasars, offering fresh insight into the evolution of galaxies in the very early Universe.

The research team was led by Qinyue Fei, a graduate student and visiting researcher from Peking University, and his colleagues from the University of Tokyo’s Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU). They were joined by researchers from Peking University’s Kavli Institute for Astronomy and Astrophysics (KIAA-PKU), the Center for Astrophysical Sciences at John Hopkin’s University, the Kavli Institute for Cosmology, Cambridge (KICC), multiple observatories and universities. Their study was published on February 5th in The Astrophysical Journal.

Using data from the Atacama Large Millimeter/submillimeter Array (ALMA), the team was able to visualize the emission line of ionized carbon (C II) in two galaxies located 13 billion light years away. Like the “hydrogen line” (H I), this refers to the spectral line created by the transition of elemental carbon into ionized carbon. This way, they were able to study the gas dynamics within the Active Galactic Nuclei (AGNs, or quasars) of these very early galaxies. The active nature of these galaxies indicates that they have supermassive black holes (SMBH) at their centers.

They then employed numerous models to determine the velocity of the gases (nonparametric) the mass distribution (parametric) of the galaxies. This was assisted by DysmalPy and 3DBarolo, two software tools specifically designed to measure the rotation curves of galaxies. According to their results, which captured the rotation curves from the inner regions to the outskirts, DM accounted for about 60% of these early galaxies. “Vera Rubin provided the first evidence for dark matter using the rotation curves of nearby local galaxies. We’re using the same technique but now in the early Universe,” said Kavli IPMU Professor (and study co-author) John D. Silverman.

Interestingly, previous studies of galaxies in the early Universe revealed a low mass fraction of DM in their outskirts. However, the data obtained by Fei and his colleagues showed a flat rotational curve, similar to massive disk galaxies observed in the local Universe. The team’s findings shed light on the intricate relationship between DM matter and SMBHs and offer crucial hints as to how galaxies evolved from the early Universe to what we observe today.

Further Reading: IPMU, The Astrophysical Journal

The post A New Study Reveals How Dark Matter Dominated the Early Universe appeared first on Universe Today.

Locomotion makes things move, and certain forms of locomotion make them move better than others. Those more effective types of locomotion change depending on the environment, which is even more true for space exploration. Methods that might work well on Earth or even other planets, such as helicopters, might be utterly useless on others. But, specialized forms of locomotion abound, and the NASA Institute of Advanced Concepts (NIAC) phase I grants for this year include a closer look at one such specialized form – jumping.

The Legged Exploration Across the Plume (LEAP) program would utilize a specially designed jumping robot to explore the lower parts of the massive plumes emitted from Enceladus. The concept is based on the Salto jumping robot, initially developed by a team at UC Berkeley. Justin Yim, now a professor at the University of Illinois and the NIAC Phase I grantee, worked on it as part of his PhD thesis.

In an interview with Fraser, Dr. Yim details what makes Salto unique. For its size, which measures only about 50 centimeters, and weight, which is planned for less than .5 kg, Dr. Yim believes the robot could jump upwards of 100m horizontally on the surface of Enceladus.

Operations of the LEAP robot – launching off from and returning to the Orbilander.
Credit – Justin Yim / NASA

That is a significant advantage over other forms of locomotion on the icy moon. Enceladus has no atmosphere, so flying would have to be powered by a rocket, which will use up fuel, rather than by rotors, like Ingenuity was able to do on Mars. However, the surface is also icy and uneven, making having a rover trundle impractical.

Jumping, however, offers the best of both worlds. It requires relatively little power and, as such, could be done multiple times without depleting a robot’s battery. But it is also terrain agnostic, soaring above the most challenging parts. It would also allow the robot to jump directly through the lower part of the plumes that Enceladus ejects into the Saturnian system, the remnants of which form one of Saturn’s spectacular rings.

No other form of locomotion would be able to get that close to the source of the plumes, and since those plumes are some of the most interesting parts of Enceladus, studying them up close is appealing for many reasons. One mission in particular, the Enceladus Orbilander, which was a proposed flagship mission that the 2023 Decadal Survey supported, would be able to capture the upper parts of a geyser as it flew through one on its orbital path but would be unable to collect any data on its lower parts. At least as initially envisioned, its lander wouldn’t be capable of moving through a geyser.

CNET video describing Salto, the inspiration for LEAP.
Credit – CNET YouTube Channel

LEAP could potentially hitch a ride with the system, though. Utilizing the lander as a launch platform would save significant design effort of the robot itself. It could even use the Orbilander as a recharging station, allowing it to explore even further afield. 

There are some challenges, though – the original design of Salto only had one reaction wheel, which allowed its engineers to control the robot pitch, allowing it to perform the feet of aligning for multiple jumps off walls, kind of like characters do in video games. However, to truly control itself, LEAP would need two other reaction wheels to control yaw and rolls, giving engineers direct control over all three axes of the robot’s orientation. Dr. Yim added that, as part of the Phase I study, the researchers planned to assess using those reaction wheels to control motion in these three dimensions to assist in righting the robot if it falls over. Inevitably, given Enceladus’s rough and icy slick surface, it will undeniably eventually fall over.

As Dr. Yim discusses with Fraser, there is always a trade-off between size, weight, and capability for robots. Even larger versions of LEAP wouldn’t necessarily be able to travel as far or as efficiently as a smaller one does – though they might be able to carry more payload. One of the limitations of a small jumping robot is the mass limits placed on its ability to jump. Therefore, Dr. Yim expects simple instrumentation, like a flow meter and a camera, to be the extent of what LEAP will be able to carry into the plume, rather than fancier instrumentation like a mass spectrometer that might provide more insight but would be too bulky for jumping.

Dr Yim discusses some of the technical background of Salto.
Credit – BiomimeticMillisys YouTube Channel

Like all NIAC Phase I projects, this one is still very early in development. The outcome of this round is expected to be a case study that shows the parameters that must be considered in any future design or prototyping. Whether or not it ends up on Enceladus, the jumping concept behind LEAP appears to be an important locomotion style for many future robots, so expect to see more jumping around near you sometime soon.

Learn More:
NASA / Justin Yim – LEAP – Legged Exploration Across the Plume
UT – A Hopping Robot Could Explore Europa Using Locally Harvested Water
UT – A Robot Hopper to Explore the Moon’s Dangerous Terrain
UT – Miniaturized Jumping Robots Could Study An Asteroid’s Gravity

Lead Image:
Artist’s depiction of the LEAP robot jumping over a geyser on Enceladus.
Credit – NASA / Justin Yim

The post A Jumping Robot Could Leap Over Enceladus’ Geysers appeared first on Universe Today.

The JWST was never intended to find asteroids. It was built to probe some of our deepest, most demanding questions about the cosmos: how the first stars formed, how galaxies have evolved, how planets like ours take shape, and even how life originated. However, it’s first and foremost a powerful infrared telescope and its unrivalled infrared prowess is helping it contribute to another important goal: defending Earth from dangerous asteroids.

Humanity doesn’t want to share the dinosaurs’ fate. About 66 million years ago, the Chicxulub impact wiped them out. An asteroid 10 to 15 km (6 to 9 mi) wide struck Earth near the Yucatan Peninsula, ending the dinosaurs’ 165-million-year reign. Only avian dinosaurs survived.

With that haunting backdrop, there’s a growing effort to identify dangerous space rocks that could strike Earth. In 2005, the US Congress directed NASA to “establish a Near-Earth Object Survey Program to detect, track, catalogue, and characterize certain near-Earth asteroids and comets.” That effort has paid dividends, especially when it comes to large asteroids that pose an existential threat.

Finding the largest main-belt asteroids hasn’t been difficult. They practically announce their presence to our powerful telescopes. Large asteroids around 100 kilometres in diameter or greater are potentially devastating, but they tend to follow stable orbits in the main belt.

However, decameter-size impactors are more elusive. These are asteroids tens of meters in diameter, and their smaller masses mean they can more easily become part of the Near-Earth Object (NEO) population due to interactions in the main belt. While these aren’t civilization-ending size rocks, they can reach Earth more frequently and cause megaton-size explosions. They’re behind the Tunguska Event in 1908 and the Chelyabinsk explosion in 2013.

The JWST is helping scientists understand this population of space rocks, and new research illustrates how. It’s titled “JWST sighting of decametre main-belt asteroids and view on meteorite sources.” It’s published in Nature, and the co-lead authors are Julien de Wit and Artem Burdanov, both from the Department of Earth, Atmospheric, and Planetary Sciences at MIT.

“Asteroid discoveries are essential for planetary-defence efforts aiming to prevent impacts with Earth, including the more frequent megaton explosions from decametre impactors,” the authors write. “Although large asteroids (~100 kilometres) have remained in the main belt since their formation, small asteroids are commonly transported to the near-Earth object (NEO) population.” NEOs are objects whose closest approach to the Sun is less than 1.3 AU. This boundary includes objects that can come close enough to cross Earth’s orbit or can be potentially influenced by Earth’s gravity.

This diagram shows the orbits of 2,200 potentially hazardous objects as calculated by JPL’s Center for Near Earth Object Studies (CNEOS). Highlighted is the orbit of the double asteroid Didymos, the target of NASA’s Double Asteroid Redirect Test (DART) mission, launched in 2021. Credit: NASA/JPL-Caltech

Most asteroids are detected with ground-based optical telescopes that sense the sunlight they reflect, which is their albedo. Relying on asteroids’ albedo measurements, though, is fraught with errors. For example, small objects with a high albedo can appear larger than large objects with a small albedo.

Asteroids also give off thermal emissions or infrared energy, and that’s where the JWST comes in. “With an exquisite sensitivity in that wavelength range and a large aperture, JWST is ideal for detecting the thermal emission of asteroids and revealing the smallest main-belt asteroids (MBAs),” the authors write in their paper.

According to the researchers, the JWST’s infrared measurements can constrain an object’s size to within 10% to 20%, while albedo measurements alone can be off by a factor of 3-4x. That’s a huge discrepancy that could lead to a risky misunderstanding of the main asteroid belt’s population.

Burdanov, de Wit, and their co-researchers developed a new way to detect decametre-size impactors with the JWST by using GPUs, Graphics Processing Units, and what the researchers call “synthetic tracking techniques.” These were initially developed to hunt for exoplanets, but the method is bearing fruit in the effort to catalogue asteroids. The researchers’ synthetic tracking method is designed to detect asteroids in data gathered from exoplanet observations. The JWST observed the TRAPPIST-1 star for more than 90 hours in 2022-23, and these results are based on that data.

“After applying our GPU-based framework for detecting asteroids in targeted exoplanet surveys, we were able to detect 8 known and 139 unknown asteroids,” the authors write. “The 139 new detections could not be attributed to any known asteroids.”

They range from the size of a bus to several stadiums wide. They’re the smallest objects ever detected in the main asteroid belt.

This figure from the new research shows the diameter, flux, and distance from the Sun for the new asteroids. “The dash-dot, solid, and dotted lines represent the size-flux relationships for objects at 2.00, 2.50, and 3.25 au, respectively,” the authors explain. Image Credit: Burdanov et al. 2025.

“We have been able to detect near-Earth objects down to 10 meters in size when they are really close to Earth,” said author Artem Burdanov in a press release. “We now have a way of spotting these small asteroids when they are much farther away, so we can do more precise orbital tracking, which is key for planetary defence.”

“For most astronomers, asteroids are sort of seen as the vermin of the sky, in the sense that they just cross your field of view and affect your data,” study co-author Julien de Wit said.

via GIPHY

de Wit explained the background of this research to Universe Today. Their interest in using the JWST in this way preceded the telescope’s launch.

De Wit and his co-researchers helped discover the TRAPPIST-1 system in 2016. In exoplanet science, objects like asteroids are considered noise that interferes with attempts to detect exoplanets. These asteroids are basically tossed aside in those efforts. In more recent years, astronomers pointed the JWST at the TRAPPIST-1 system and used its infrared capabilities to measure the temperature of the innermost planet and observe stellar flares. Those observations created what de Wit calls “bonus science.”

“Our main line of work relates to detecting and studying exoplanets like the TRAPPIST-1’s seven terrestrial gems,” de Wit explained. “But over the years, we’ve also been wanting to do more with all the astronomical data gathered by exoplanet surveys, and we started mining these fields of view for “bonus science.” One of them relates to detecting objects crossing the field of view, like asteroids. We perfected our methodology ahead of JWST, knowing that synthetic tracking combined with JWST’s unparalleled capabilities in the infrared (part of the wavelength range where these asteroids are the brightest) would change the game.”

These results are just a beginning. Every time the JWST is trained on something, it creates data. All of that data can be combed through to detect more asteroids and to try to understand what family they belong to. Decameter-size asteroids are likely the result of collisional cascades, and researchers would like to understand some of those relationships.

“There is a LOT more archival data to be used as done here. We are now gearing up to mine all of it,” de Wit explained, though it depends on funding. “This would allow us to study the 3D structure of the main belt and relate different sub-populations of these decameter asteroids to specific families of asteroids (and meteorites)!”

We’re expecting thousands of these asteroids in the existing MIR data!” said de Wit.

The discovery of the potentially dangerous asteroid 2024YR4 has focused peoples’ attention on the asteroid threat. It’s a NEO with a small chance of impacting Earth in 2032, though scientists caution against any panic. It’ll pass close to Earth again in 2028 and will be subjected to more precise observations and a reassessment of its risk.

Observing time with the JWST is a hot commodity. We asked the researchers if they’ll have an opportunity to use the space telescope to purposefully detect more asteroids.

“We did put forth a “catch me if you can” proposal with the intent of demonstrating JWST’s capabilities to detect decameter MBAs and then follow up on them to constrain their orbits as a “performance test” for planetary defence efforts,” de Wit said. He explained that “possible impactors often have their aphelion up in the main belt and constraining their orbit well can use observations all the way out there.” Their proposal is waiting for approval.

The 139 new asteroids detected in the main belt are bonus science. The team’s observation method had limitations and wasn’t dedicated to finding the smallest asteroid. However, there’s a lot more JWST data waiting to be mined, and with a more dedicated effort, de Wit and his co-researchers could detect many more.

“An observational setup that would allow for JWST to “drift” along the expected motion of smaller asteroids in the main belt while performing longer exposures would allow for asteroids below 10 meters to be detected,” de Wit told Universe Today.

“With an observational set up dedicated to detecting the smallest main-belt asteroids, we could go much smaller,” de Wit concluded.

Press Release: MIT astronomers find the smallest asteroids ever detected in the main belt

Research: JWST sighting of decametre main-belt asteroids and view on meteorite sources

The post JWST Finds the Smallest Asteroids Ever Seen in the Main Belt appeared first on Universe Today.

A new study sheds light on how the extreme miniaturization of thin films affects the behavior of relaxor ferroelectrics -- materials with noteworthy energy-conversion properties used in sensors, actuators and nanoelectronics.

The future of manufacturing is not just about machines and AI; it's about re-empowering humans, according to a new study.

The future of manufacturing is not just about machines and AI; it's about re-empowering humans, according to a new study.

Qubits -- the fundamental units of quantum information -- drive entire tech sectors. Among them, superconducting qubits could be instrumental in building a large-scale quantum computer, but they rely on electrical signals and are difficult to scale. In a breakthrough, a team of physicists has achieved a fully optical readout of superconducting qubits, pushing the technology beyond its current limitations.

Qubits -- the fundamental units of quantum information -- drive entire tech sectors. Among them, superconducting qubits could be instrumental in building a large-scale quantum computer, but they rely on electrical signals and are difficult to scale. In a breakthrough, a team of physicists has achieved a fully optical readout of superconducting qubits, pushing the technology beyond its current limitations.

Triple click chemistry has revolutionized chemical synthesis with its simplicity and efficiency, allowing for the quick and selective assembly of complex molecules. Now, in a recent study, researchers developed novel trivalent platforms capable of producing highly functional triazoles in straightforward one-pot reactions. These platforms have significant potential in drug development, materials science, and bioengineering, promising advancements in sustainable chemistry and biomedical innovations.

Researchers have developed an artificial intelligence (AI) tool that will help predict endangered whale habitat, guiding ships along the Atlantic coast to avoid them. The tool is designed to prevent deadly accidents and inform conservation strategies and responsible ocean development.

Rhobo6, a light microscopy probe, gives scientists an unprecedented look at the extracellular matrix -- the collection of organized molecular structures that fills the spaces between cells in our bodies.

A major challenge in self-powered wearable sensors for health care monitoring is distinguishing different signals when they occur at the same time. Researchers addressed this issue by uncovering a new property of a sensor material, enabling the team to develop a new type of flexible sensor that can accurately measure both temperature and physical strain simultaneously but separately to more precisely pinpoint various signals.

Researchers have discovered that superconducting nanowire photon detectors can also be used as highly accurate particle detectors, and they have found the optimal nanowire size for high detection efficiency.

The appearance of the Interstellar Objects (ISOs) Oumuamua and Comet Borisov in 2017 and 2019, respectively, created a surge of interest. What were they? Where did they come from? Unfortunately, they didn’t stick around and wouldn’t cooperate with our efforts to study them in detail. Regardless, they showed us something: Milky Way objects are moving around the galaxy.

We don’t know where either ISO came from, but there must be more—far more. How many other objects from our stellar neighbours could be visiting our Solar System?

The Alpha Centauri (AC) star system is our nearest stellar neighbour and consists of three stars: Alpha Centauri A and Alpha Centauri B, which are in a binary relationship, and Proxima Centauri, a dim red dwarf. The entire AC system is moving toward us, and it presents an excellent opportunity to study how material might move between Solar Systems.

New research to be published in the Planetary Science Journal examines how much material from AC could reach our Solar System and how much might already be here. It’s titled “A Case Study of Interstellar Material Delivery: Alpha Centauri.” The authors are Cole Greg and Paul Wiegert from the Department of Physics and Astronomy and the Institute for Earth and Space Exploration at the University of Western Ontario, Canada.

“Interstellar material has been discovered in our Solar System, yet its origins and details of its transport are unknown,” the authors write. “Here we present Alpha Centauri as a case study of the delivery of interstellar material to our Solar System.” AC likely hosts planets and is moving toward us at a speed of 22 km s?1, or about 79,000 km per hour. In about 28,000 years it will reach its closest point and be about 200,000 astronomical units (AU) of the Sun. According to Greg and Wiegert, material ejected from AC can and will reach us, and some is already here.

AC is considered a mature star system about five billion years old that hosts planets. Mature systems are expected to eject less material, but since AC has three stars and multiple planets, it likely ejects a considerable amount of material. “Though mature star systems likely eject less material than those in their
planet-forming years, the presence of multiple stars and planets increases the likelihood of gravitational scattering of members from any remnant planetesimal reservoirs, much as asteroids or comets are currently being ejected from our Solar System,” the authors write.

We know that macro objects like Borisov and Oumuamua have reached our Solar System, and we also know that interstellar dust has reached our system. The Cassini probe detected some, and researchers reported on it in 2003. Existing models for material ejection from star systems are partly based on what we know about our Solar System and how it ejects material, and Greg and Wiegert based their work on those models.

Artist’s impression of `Oumuamua. While large ISOs like this grab our attention, dust particles from other star systems are also interstellar objects. Credit: ESO/M. Kornmesser

The research shows that there are potentially large quantities of material from AC. The authors write that “the current number of Alpha Centauri particles larger than 100 m in diameter within our Oort Cloud to be 106,” or 1 million. However, these objects are extremely difficult to detect. Most of them are likely in the Oort Cloud, a long distance from the Sun. The pair of researchers explain that “the observable fraction of such objects remains low” and that there is only a one-in-a-million chance that one is within 10 AU of the Sun.

This animation brings some of the research results to life. “Alpha Centauri’s orbit about the Galactic Centre viewed on the xy and yz planes (top row), as well as the orbits of the ejecta from Alpha Centauri viewed in a comoving frame (bottom row). Our Sun (Sol) is marked by a black hexagon, and its orbital path is indicated by a grey solid line (top row only). Alpha Centauri’s location and path are shown by a yellow star and a solid blue line (top row only). In the bottom row, the comoving frame follows Alpha Centauri around its orbit while maintaining its orientation with the y-axis pointing towards the Galactic Centre (blue arrow) and Alpha Centauri’s velocity pointing in the -x direction (black arrow). This still frame is taken at t?3,000 yr (that is, +3,000 years from the current epoch) after ~100 Myr of integration. The colours of the ejecta represent the 3rd dimension of position, except that any particle that will at any point come within 100,000 au of Sol is plotted in red. This shows the time evolution from t? -100 Myr to t? 10 Myr,” the authors write.

The researchers ran simulations to determine how much material can reach us from AC. The simulations ran for 110 million years from t= -100 myr to t= 10 myr. During that span, AC ejected 1,090,000 particles. They were ejected in random directions at different speeds, and only a tiny amount came anywhere near the Sun. “Only a small fraction of the AC ejecta come within the CA (close approach) distance of the Sun. In total, 350 particles had a CA with the Solar System, ~0.03% of the total ejecta,” the authors explain.

This figure from the study focuses on the 360 particles that make close approaches. “The heliocentric equatorial radiant for the 350 close approaches at the time of their closest Solar approach (“Arrival Time”), with the current heliocentric equatorial coordinates of Alpha Cen plotted as a black star and the “effective radiant” corresponding to Alpha Cen’s apparent velocity is plotted as a red star. The purple-shaded region is the combined projection of the effective cross-section of the Solar System (solid angle size as seen from Alpha Cen) from the start of the simulation up to the current time.”

The research shows that there are plausible pathways for particles from AC to reach our Solar System. How large can they be?

According to the authors, small particles that would appear as meteors in Earth’s atmosphere are not likely to reach us. They’re subjected to too many forces on their way, including magnetic fields, drag from the interstellar medium, and destruction through sputtering or collisions. “Small particles travelling through the interstellar medium (ISM) are subject to a number of effects not modelled here,” they explain.

They computed the minimum size of particles that could make the journey. “We extracted the relevant parameters for each of the 350 CAs from our simulation and computed the minimum size needed for a grain travelling along that trajectory to survive all three effects,” the authors write. They found that a particle with a median of 3.30 micrometres can survive the journey.

“At this size and speed, the particle can travel 125 pc in the ISM before grain destruction becomes relevant, 4200 pc for ISM drag, and only 1.5 pc for magnetic forces, and thus our typical particles are effectively magnetically limited,” the researchers explain. “In fact, all of our particles are limited by magnetic forces.” The authors also point out that these tiny grain sizes are undetectable by meteor radar instruments like the Zephyr Meteor Radar Network.

These results are hampered by our poor understanding of our Solar System’s material ejection rate, on which the research is partly based. “Unfortunately, the rate of ejection of material from Alpha Cen is poorly constrained,” write Greg and Wiegert.

However, with that in mind, the research shows that some material can reach us and is already here. Most of it travelled for less than 10 Myr to reach us, but it has to be larger than about 10 microns to survive the journey. It also estimates that about 10 particles from Alpha Centauri become detectable meteors in Earth’s atmosphere currently, with that number increasing by a factor of ten in the next 28,000 years.

This research presents a concrete example of how our Solar System is anything but isolated. If material from star systems can move freely to and from one another, it opens up another window into the planet formation process. If AC does host exoplanets, some of the material reaching us could be from the same reservoir of material that those planets formed from. It could be possible to learn something about those planets directly without having to overcome the vast distance between us and Alpha Centauri.

“A thorough understanding of the mechanisms by which material could be transferred from Alpha Centauri to the Solar System not only deepens our knowledge of interstellar transport but also opens new pathways for exploring the interconnectedness of stellar systems and the potential for material exchange across the Galaxy,” the authors conclude.

Research: A Case Study of Interstellar Material Delivery: Alpha Centauri

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