Edge of The Milky Way found

 The edge of the Milky Way is finally found, scientists claim 

Astronomers just found the Milky Way’s true “edge”, and it’s defined not by stars forming, but by stars quietly drifting beyond it. Scientists have uncovered the true boundary of the Milky Way’s star-forming region using stellar “age mapping.” They found a telltale U-shaped pattern showing that star formation drops sharply around 35,000–40,000 light-years from the center. Beyond that, stars are mostly migrants, slowly drifting outward rather than forming in place. The discovery gives a long-sought answer to where our galaxy’s stellar nursery really ends. The question is harder to answer than one might expect. Since we're inside the galaxy itself, it's obviously hard to judge the "edge" to begin with. But it gets even more complicated when defining what the edge even is, the galaxy simply gets less dense the farther away from the center it goes. A new paper by researchers originally at the University of Malta thinks they have an answer. The Milky Way’s star-forming zone ends about 40,000 light-years from its center, revealed by a surprising reversal in star ages. Beyond that edge, stars aren’t born, they’ve migrated there over time like cosmic hitchhikers.

Defining where the Milky Way ends has always been challenging because its disk does not stop abruptly, it gradually fades into space. Now, for the first time, an international team of astronomers has pinpointed the boundary of the Galaxy's star-forming disk by examining the ages of stars. The "edge" can be defined as the star-forming region, and in their paper, they very clearly show that "edge" to be between 11.28 and 12.15 kiloparsecs (or about 40,000 light years) from the center. Even finding that edge was no easy task, though. The researchers had to analyze the ages of over 100,000 giant stars from the data of several different surveys, including APOGEE-DR17, LAMOST-DR3, and Gaia. In the data they found an interesting story about the evolution of the position of stars in the galaxy and their age. That relationship can be thought of as a U curve. In this case, the Y axis is age, and the X axis is the distance from the galaxy's center. In words that simply means that stars closer to the center of the galaxy are older, and get progressively younger out to a certain point, and then start getting older again. This 'certain point', according to the authors, is the end of the galaxy's star-forming region, and hence, the "edge" of the galaxy. To reach this conclusion, researchers combined measurements of the ages of bright giant stars with advanced simulations of galaxy evolution. This approach revealed a distinct "U-shaped" pattern in how stellar ages are distributed, which marks the outer limit of active star formation in our Galaxy. "The extent of the Milky Way's star-forming disc has long been an open question in Galactic archaeology; by mapping how stellar ages change across the disc, we now have a clear, quantitative answer," remarked the paper's lead author, Dr. Karl Fiteni. 

U-shaped curve of the galaxy's age and depiction of its "edge".  So why the U-curve? There are a few reasons. Closer to the black hole at the center of the galaxy, there was much more gas and dust, leading to earlier star formation, and hence older stars. Farther out, gas and dust is more spread out, the gravitational attraction that eventually results in star formation happens more slowly. Hence, stars get younger and younger out to the "edge". But what happens beyond that edge? Why are there still stars, and why are they older? The simple answer is that the outer reaches past the galaxy's "edge" are populated with migrant stars that were formed within the star-forming region and then, for one reason or another, were pushed out past it. The two main causes of that migration are gravitational forces from the spiral arms themselves, or the "central bar" that can cause stars to slingshot out of the star-forming region of the galaxy. Galaxies do not build stars evenly across their disks. Instead, they grow from the center outward. Star formation begins in dense central regions and slowly spreads outward over billions of years, a process known as "inside-out" growth. As a result, stars are generally younger at greater distances from the center, since those outer regions began forming stars more recently. The Milky Way follows this pattern up to a point. The stellar ages decrease with distance from the center, as expected. However, at roughly 35,000 to 40,000 light-years from the Galactic Center, this trend reverses. Beyond this region, stars become older again with increasing distance, forming the characteristic U-shaped age profile.

By comparing this pattern with detailed galaxy simulations, the researchers determined that the point where stellar ages are youngest corresponds to a sharp decline in star formation efficiency. This confirms it as the true boundary of the Milky Way's star-forming disk. "The data now available allow increasingly precise stellar ages to serve as powerful tools for decoding the story of the Milky Way, ushering in a new era of discovery about our home Galaxy," commented Prof. Joseph Caruana, co-author and supervisor of the project based at the University of Malta. "In astrophysics, we use simulations run on supercomputers as a tool to identify the physical mechanisms responsible for creating the features we observe in galaxies, such as the Milky Way. In our current study, for example, these simulations helped us to demonstrate how stellar migration shapes the stellar age profile of galaxies, allowing us to identify the edge of our Galaxy's star-forming disc." said Dr. João A. S. Amarante of Shanghai Jiao Tong University. So while the inner regions of the galaxy are made of older stars, the outer regions are as well, since they have migrated there over billions of years. But why is there a distinct "cut off" of star formation at 40,000 light years? The paper offers three reasons. First is the Outer Lindblad Resonance of the central bar of the galaxy, which can disrupt gas flow, trapping it in the interior of the galaxy. Second is a "galactic warp" of the galactic plane at this distance, further diffusing the gas over a larger area. A third explanation is that the gas itself might simply become too thin to cool down and accrete into star-forming regions.

To uncover the boundary, the team analyzed more than 100,000 giant stars. They used spectroscopic data from the LAMOST and APOGEE surveys along with precise measurements from the Gaia satellite, which is mapping stars across the Milky Way in unprecedented detail. By focusing specifically on stars orbiting within the Galaxy's main disk, the researchers were able to isolate the signature of inside-out growth. This allowed them to separate it from other processes which can affect stellar motion and distribution. Prof. Laurent Eyer, a co-author from the University of Geneva, remarked: "Gaia is delivering on its promise: by combining its data with ground-based spectroscopy and galaxy simulations, it allows us to decipher the formation history of our Galaxy." The team then used advanced simulations to confirm their interpretation. These models showed that the U-shaped age pattern naturally arises when star formation drops sharply and older stars migrate outward, reinforcing the idea that this marks the true edge of the star-forming disk. It clearly defines the Milky Way as a Type-II (down-bending) disc galaxy, sharing that profile with around 60% of similar galaxies in the local universe. But perhaps more importantly, it helps us understand a wider part of the story of the Milky Way itself.

If star formation drops off so sharply at this boundary, it raises an obvious question. Why are there still stars beyond it? The answer lies in a process called "radial migration", stars gradually moving outward from their birthplaces by interacting with spiral waves in the Galaxy. Much like surfers riding ocean waves, stars can gain momentum from spiral arms and drift to larger distances over time. Beyond the edge, most stars did not form locally. Instead, they slowly migrated outward. Because this process is gradual and random, it takes longer for stars to reach farther distances. This explains why the most distant stars beyond the boundary tend to be the oldest. Importantly, these stars travel in nearly circular orbits. This rules out the idea that they were thrown outward by collisions with other galaxies. Their presence in the outer disk reflects the steady influence of internal Galactic dynamics. Prof. Victor P. Debattista, co-author and co-supervisor of the study at the University of Lancashire, explained: "A key point about the stars in the outer disc is that they are on close to circular orbits, meaning that they had to have formed in the disc. These are not stars that have been scattered to large radii by an infalling satellite galaxy." We can clearly define where the Milky Way's productive youth ends, and its sprawling, quieter outskirts begin. And simply knowing that makes us more connected to our Solar System's most immediate neighbors, no matter their age.

Although the location of the boundary is now clear, the reason star formation drops off at this distance remains uncertain. One possibility is the Milky Way's central bar, whose gravity may cause gas to accumulate at certain radii. Another is the Galaxy's outer warp, where the disk bends and could disrupt the conditions needed for star formation. While the exact cause is still being investigated, the research confirms that the U-shaped age pattern is a reliable indicator of the Milky Way's star-forming limit. Upcoming surveys such as 4MOST and WEAVE will provide even more detailed observations, helping astronomers refine these measurements and better understand what shapes the Galaxy's structure. The study also highlights how measuring stellar ages, once a major challenge, has become a powerful tool for exploring Galactic history. By tracking how stars formed and moved over billions of years, scientists are gaining a clearer picture of how the Milky Way came to be in our universe.

Muhammad (Peace be upon him) Name

 

ALLAH Names

 

Separation and Purification Technology for rare earth metals

 Extraction of  rare earth metals from water with Magnets

From cell phones to wind turbines and missile defense systems, modern technologies depend on critical minerals like rare earth elements. As demand grows, researchers are exploring more efficient and adaptable methods to recover and reuse these materials. A new study suggests that magnets make the process more efficient. Common solid magnets made from iron-based alloys can help concentrate rare earth elements in underwater environments, where they may accumulate and form crystals. This research provides a groundbreaking and cleaner way to recover materials for modern technology efforts. Inside a liquid cell beside a magnet, rare earth ions gather into concentrated bands, rather than remaining evenly mixed. Researchers show how simple magnets can help solve a complex problem. Waste from coal power plants, mining operations and oil and gas wells contains trace amounts of rare earth elements, such as dysprosium and lanthanum, which are used in electric vehicles, rechargeable batteries and defense technologies. Watching those bands take shape at the Pacific Northwest National Laboratory (PNNL), Giovanna Ricchiuti showed that magnetic gradients alone could be what drives this separation. The effect did more than nudge the ions closer to the magnet, because it created distinct zones where the metals became far more concentrated than the surrounding liquid. This early sorting step is crucial regarding the challenge of separating nearly identical metals.

Current industrial methods for extracting these elements from domestic feedstocks depend on complex processes that are energy-, cost- and time-consuming, and produce significant chemical waste. University of Mississippi doctoral student Ivani Jayalath collaborated with a team of researchers in the Non-Equilibrium Transport Driven Separations initiative at Pacific Northwest National Laboratory to develop new methods for recovering critical minerals. Their results show that magnets streamline this process while reducing energy and chemical consumption as well as waste generation. Coal ash, mine tailings, and produced water, salty wastewater from oil and gas wells, can all carry trace rare earths. Current plants usually rely on liquid solvents or specialty resins, repeated chemical steps, in order to tease similar metals apart. “Traditional separation methods use large amounts of organic solvents,” said Ivani Jayalath. Each extra step raised cost, burned energy, and left more liquid waste before the metal ever reached a factory. Rare earth elements keep phones, turbines, batteries and defense hardware working because their unusual properties enable compact, high-performance parts. “There is an urgent demand for rare earth elements due to recent technological advancements and supply chain disruptions,” said Ricchiuti. Separating many lanthanides, a closely related family of rare earth metals, is hard because they behave almost like chemical twins when placed in solution. The near-twin composition has left valuable material trapped in waste streams which still resist easy, low-cost recovery.

"This presents a challenge as most of these elements have very similar chemical and physical properties. Because of their similarities, it is very difficult to find an efficient way to separate them. We exploit small differences in magnetic susceptibility, or the magnetic moment of these ions. Based on these small differences, we use magnetic field gradients to drive selective transport and separation." said Giovanna Ricchiuti. At PNNL, the team used Mach-Zehnder interferometry, a laser method for tracking tiny density changes in liquid. As ions moved, the instrument recorded enrichment zones near the magnet and depletion zones where the liquid lost those ions. Ricchiuti explained that the magnetic field drives shifting waves of ion concentration, creating regions where ions cluster. Others are pushed away through a balance of magnetic motion, diffusion, and electric forces generated within the liquid. The wave-like patterns showed that the magnet was not merely holding ions in place but constantly redistributing them over time. Despite the similarities between the elements, they respond differently to magnetic field gradients, allowing researchers to use a simple permanent magnet to separate targeted elements from other components in liquid feedstocks. Unlike traditional methods, the process is also faster and produces less chemical waste.

The new approach worked by exploiting magnetic susceptibility, a measure of how strongly a substance responds to a magnetic field. Heavy ions such as dysprosium, a rare earth metal used in high-performance magnets, felt a stronger pull than lighter ones such as lanthanum in the same liquid. A field that changed across space could nudge one group toward the magnet while another lagged or drifted away. The small magnetic contrast gave engineers a new sorting handle. Before, relying upon chemistry alone offered very little separation power. Magnetic pull was only part of the story, because the rearranged ions also built electrochemical potentials, local voltage-like differences inside the liquid. When charge became uneven, self-generated electric fields pushed back on diffusion and helped organize the migrating ions. This model explained how a weak permanent magnet could still create long-range movement without outside power. Electrical feedback turned a simple magnet into an active separation tool rather than an inert object beside the beaker. Traditional separation methods use large amounts of organic solvents. This increases waste disposal costs and can cause harmful environmental effects. Using magnets offers a simple and potentially more sustainable way to assist separation processes. Magnetic fields helped drive selective ion transport and concentration from solution.

The national laboratory developed an imaging system which uses lasers to detect the movement of ions in real time, Ricchiuti said. This system allows the researchers to observe enrichment zones, areas where ions are concentrated in response to the magnet, and depletion zones, or areas where ions are repelled from the magnet. When a common chemical called oxalate was added, the concentrated metal ions began forming a solid compound right at the magnet’s surface, making them easier to collect. Crystallization helped because a solid can be separated more easily than the same metal dissolved across a large liquid volume. Near the magnet, concentrations rose to three to four times the bulk solution, enough to push the system toward that solid state. The result showed that magnets could help move the metal from a dissolved state into a solid form that can be collected. “Using magnets offers a simple and potentially more sustainable way to assist separation processes,” said Jayalath. Because permanent magnets need no continuous electrical input, the method pointed toward lower operating energy than voltage-driven systems. Early technoeconomic estimates suggest that this would result in lower chemical costs. compared to standard methods for magnet-responsive rare earths. The provisional savings still explained why a lab result could attract serious industrial interest.

The magnetic field creates dynamic 'ion concentration waves' and enrichment or depletion zones due to the interplay of magnetic drift, diffusion and self-generated electric fields. When the researchers combined a precipitating agent with a magnetic field, they observed enhanced crystallization of the dissolved rare earth elements, making them easier to extract. This was an initial study, and the team used simplified solutions rather than abstract chemistry found in industrial waste. Real waste streams can contain competing ions, suspended particles and changing acidity, each of which could complicate the magnetic effect. Large systems will also need careful design so magnets, flow paths and crystal collection steps keep working at industrial volumes. The limits align the future agenda for scaling-up instead of undercutting passive magnetic gradients that can drive useful transport. A cheap magnet, in the right geometry, can move scarce metals, reshape the liquid around them, and start converting them into recoverable solids. If future tests handle real waste streams, the approach could build domestic supply chains while wasting far fewer chemicals. Implementing a magnet-based approach is a potentially promising step toward improving current extraction processes. "The world is looking for robust and sustainable energy and supply chains for critical minerals," Jayalath said. "We need these elements for electric cars, batteries and other technologies. So, they are essential for the future. That is why we need to focus on how to extract and recycle these elements efficiently."

Muhammad (Peace be upon him) Name