Black Hole

Earth from space The Chinese geostationary satellite FY-4B captured an image of our planet on August 9 🌏.

A “Stranger” Hides Beyond Neptune: Its Orbit Defies Predictions and Goes Against the Flow of the Solar System Imagine this: in 1983 the infrared satellite IRAS “blinked” at a distant cold object, and 23 years later the Japanese AKARI observatory spotted a similar point of light in a different part of the sky. If it’s the same body, it moved roughly one-and-a-half full Moon diameters across the sky in a quarter of a century. And it is not moving the way every “normal” planet in the Solar System does. Astronomers Mike Brown and Konstantin Batygin (the same pair who proposed the Planet Nine hypothesis in 2016) looked at the apparent motion and calculated an orbital inclination of about 120°. That is almost reverse motion — opposite to the direction of all eight known planets. Planet Nine, according to their models, should have a modest inclination of only 15–20°. So this candidate is clearly not the object they have been hunting. Batygin jokingly called the find Planet 8.5 — “another large world, nothing like the one we predicted.” Why it is so hard to see Ordinary telescopes are almost powerless: at distances of tens of billions of kilometres the object reflects almost no sunlight. Even a cold planet, however, still emits its own heat, which infrared instruments can detect. Researchers sifted through hundreds of thousands of sources in the IRAS (1983) and AKARI (2006) archives, narrowed the list to 13 pairs, and then manually reduced it to one. The possible distance is 500–700 astronomical units (75–105 billion km from the Sun), with a mass estimated at 7–17 Earth masses. Exact measurements do not yet exist. Caution is essential Two points of light separated by decades are not yet proof. They could be unrelated objects (variable stars, distant galaxies), measurement errors, or pure coincidence. So far no one has confirmed that the source is the same, and a reliable orbit cannot be reconstructed. Interest is fuelled by the old Kuiper Belt puzzle: the orbits of some distant icy bodies look strangely ordered, as if an unseen massive planet is shepherding them. Some scientists argue this is just an observational bias (telescopes have not surveyed the whole sky equally thoroughly). The archival candidate adds a new, unexpected possibility — an object on a retrograde orbit. What comes next Modern instruments can confirm or rule out the candidate: the DECam camera in Chile and especially the Vera C. Rubin Observatory, which has already begun finding faint moving objects on the outskirts of the Solar System (including the dwarf-planet candidate 2026 ED138). If telescopes catch the body in the predicted location and track its path, we will know whether the old infrared signals belonged to another large planet or were simply a beautiful optical illusion. Neither Planet Nine nor this “stranger” has been officially discovered yet. But the idea that a world spinning “against the flow” might be hiding on the outer edges of the Solar System is already forcing us to rethink the familiar picture.

A Cosmic Odd Couple Caught in a Rare Evolutionary Moment Deep inside the crowded globular cluster NGC 362, about 29,300 light-years away, astronomers have found a striking stellar pair: a rapidly spinning millisecond pulsar and the youngest white dwarf companion ever identified next to one. The pulsar, NGC 362D, rotates once every 5.83 milliseconds—more than 10,000 times per minute. These extreme “cosmic lighthouses” form only in binary systems. A companion star swells, spills material onto the neutron star, and spins it up to incredible speeds in a process called recycling. What makes this system special is the timing. The companion, COM-NGC 362D, is a low-mass helium white dwarf still in its earliest “pre-cooling” phase. Models indicate the mass-transfer phase ended only about 600 million years ago—making it the youngest white dwarf partner to a millisecond pulsar known so far. By combining radio data from the pulsar with a decade of Hubble ultraviolet and near-infrared observations, researchers led by Greta Ettorre found another clue: residual material still surrounding the young white dwarf, left over from the recent mass transfer. This material appears to dim some of its ultraviolet light, offering a rare snapshot of the system right after the recycling process finished. “What makes this system particularly interesting is the possibility of observing it at a very early stage of its evolution,” Ettorre said. These natural clocks, with their ultra-precise pulses, help test gravity and general relativity under extreme conditions. Catching one so soon after it was spun up gives astronomers a valuable laboratory for understanding how these remarkable objects form and evolve.

We’re probably living in the galactic boondocks — and even if aliens have already built a “galactic internet,” we almost certainly can’t join it. Japanese astrophysicist Koji Tsumura from Tohoku University decided to test one of the boldest ideas out there: what if other civilizations in the Milky Way don’t just exist, but have already been searching for each other and built a shared communication network? How realistic is it for our civilization to connect to that network? The answer is pretty grim: almost impossible. Why almost no one can hear us There are billions of Sun-like stars in the Galaxy, and millions of them should have planets in the habitable zone. The classic Drake equation suggests there ought to be a lot of intelligent civilizations. But then we run into the famous Fermi paradox: “So where is everybody?” Tsumura started from the most optimistic scenario — civilizations exist, they’re active, and they’ve already built a galaxy-wide network. Even then, everything depends on location. The galactic habitable zone isn’t the entire Galaxy; it’s a relatively narrow band where three things line up: - enough heavy elements to form planets, - stars that live long enough, - and not too many nearby supernovae sterilizing everything around them. Modeling showed that the most densely populated part of the Galaxy is probably about 3,000 light-years closer to the center than the Solar System. We’re sitting roughly 26,000 light-years from the center — on the rather distant periphery. Out in these “suburbs,” the chances of plugging into a shared network are essentially zero. Either there are simply too few civilizations for a network to exist at all. Can we at least detect anyone? Detecting even one extraterrestrial civilization is theoretically possible, but only if it: - exists at the same time as we do, - is deliberately beaming a signal toward the Sun, - and is doing so in a way we can actually notice. According to Tsumura’s calculations, the fact that we still haven’t heard anyone means there’s a 35–38% chance that there really is nobody within about 6,000 light-years of us. But there’s a 61–65% chance that civilizations do exist — we just can’t detect them for some reason. In other words: our cosmic loneliness is not yet proof that the Milky Way is empty. We might simply be sitting in a quiet neighborhood where signals either don’t reach us or arrive too weakly to notice. The study is available on arXiv (arxiv org/abs/2610.20475).

Worlds Where Alien Astronomers Could Watch Planets Reverse Course On certain nearby rocky planets in the habitable zone, the night sky might regularly show a neighboring world briefly reversing direction against the stars—something visible to the naked eye. A new study identifies two especially promising examples close to Earth. From the surface of GJ 1002 b (about 16 light-years away), an observer could watch the neighboring planet GJ 1002 c loop backward in the sky. Similarly, from Teegarden’s Star c (only 12.5 light-years away), Teegarden’s Star d would display clear retrograde motion. These are not distant, telescope-only phenomena. The geometry of these compact systems around red dwarf stars makes the apparent reversal potentially easy to see with the unaided eye under the right conditions. The paper, published in *Monthly Notices of the Royal Astronomical Society*, explores how such views could shape an alien civilization’s understanding of the cosmos. Just as ancient observers on Earth watched Mars and other planets loop backward—eventually helping spark the Copernican realization that we are not the center of the universe—hypothetical astronomers on these worlds might reach the same insight by simply looking up. The study does not claim that life or civilizations exist on these planets. It simply notes that the conditions for a naked-eye “alien Copernicus” moment are present in at least two nearby systems. In short: if anyone is watching the skies from these rocky worlds, they already have a front-row seat to one of the most important ideas in the history of astronomy.

The Veil Nebula An image of an alien can be seen within this cosmic object 🌌.

Unusual radio signal from a quiet red dwarf just 11.5 light-years away International astronomers have dug an intriguing low-frequency radio signal out of LOFAR archive data, coming from the red dwarf GJ 725A — a relatively calm star in a binary system only 11.5 light-years from Earth. The detection was made on 11 December 2020: the emission lasted about an hour in the 42–50 MHz band (peaking near 45 MHz) and was strongly circularly polarized (up to 74 %). This is the lowest-frequency reliable detection of radio emission from a stellar system. Normally such “quiet” red dwarfs are almost silent at radio wavelengths, so the discovery was unexpected. ### What could it be? The signal is coherent — produced by a synchronized process rather than random noise — similar to the powerful radio bursts generated by Jupiter’s auroras. The brightness temperature reaches on the order of 100 trillion kelvin. That does not mean the material is actually that hot; the number simply reflects extremely high emission intensity. Scientists are considering three main explanations: 1. **The star itself** briefly “woke up” and produced a magnetic flare, even though it is usually quiet. 2. **The known planet** GJ 725Ab (minimum mass ~2.8 Earth masses, orbital period 11.2 days) is interacting with the star’s magnetosphere — energy flows along magnetic field lines and generates radio waves near the star. 3. **An as-yet undetected massive planet** with a strong magnetic field (~18 gauss, comparable to Jupiter). In that case we might have caught the planet’s own polar radio emission. However, matching the observed power would require an extra energy source, so this remains the most speculative idea. The signal has not been seen again in other observations. If future bursts repeat with a period close to 11.2 days, that would strongly support magnetic interaction with the known planet. Additional low-frequency radio data, together with X-ray and ultraviolet observations, should help pin down the origin. Why it matters Such signals offer a rare chance to “listen” to magnetic fields and space weather in exoplanet systems. We are beginning to hear how stars and planets talk to each other through magnetic fields — and even our nearest neighbors can still surprise us. The study has been accepted for publication in *Astronomy & Astrophysics* and is available on arXiv.

That’s no Moon—it’s Venus, wearing its rarest and most dramatic disguise. Every year and a half, Venus slips almost directly between us and the Sun. From Earth it becomes a razor-thin crescent, the kind that can fool you into thinking you’re looking at a new Moon. But Venus refuses to play by lunar rules. Its thick, carbon-dioxide atmosphere bends and scatters sunlight around the planet’s edge, stretching the glowing arc past a perfect half-circle. The tips lengthen into luminous “horns” that curl farther than geometry alone would allow—an ethereal, almost living crescent that seems to wrap itself around the night side. The effect is brief and spectacular. Catch it in the days around inferior conjunction and even a modest telescope (or steady binoculars at twilight) will show you a planet that looks less like a world and more like a glowing scythe suspended in the sky. Next time you spot a delicate crescent near the Sun, look twice. It might not be the Moon at all—it might be Venus, briefly wearing horns.

To Mars in 45 days: nuclear engines could rewrite the rules of spaceflight Imagine a journey to Mars taking not half a year, but just a month and a half. NASA is considering nuclear rocket engines precisely as a way to so radically speed up crewed expeditions. According to specialists’ calculations, such systems could cut the flight to 45–60 days. Less time en route means less radiation, less weightlessness, and lower risk for the crew. Conventional rockets work through a chemical reaction between fuel and oxidizer. Nuclear ones get their energy from a reactor. There are two main approaches. In a nuclear thermal engine, the reactor heats a propellant — usually hydrogen. The hot gas rushes out through a nozzle and creates thrust. Such a system can be roughly twice as efficient as chemical engines in terms of specific impulse: either less fuel for the same task, or more payload. In the nuclear electric variant, the reactor generates electricity that powers ion thrusters. Their thrust is modest, but they can operate for a very long time, gradually accelerating the spacecraft. These systems are especially interesting for robotic missions and delivering heavy equipment. NASA has long used nuclear power sources in space: radioisotope generators have powered Curiosity, Perseverance, and the Voyagers for years. But those are not engines — they produce electricity, not thrust. For interplanetary flights, far more complex challenges must be solved: compact reactors, heat rejection, and safety in the conditions of space. Among the promising directions is the SR-1 Freedom project, a demonstration of a nuclear power system in space. The same technologies are being considered not only for Mars, but also for flights to the moons of Jupiter and Saturn, as well as for faster journeys to the outer reaches of the Solar System. For now, nuclear rocket engines for humans remain a promising development. When they become reality depends on testing and solving safety issues. But if the calculations hold up, the road to Mars will stop being a months-long ordeal and turn into a relatively short flight.

The Universe Might Be Nearly Twice as Old—and Dark Matter and Dark Energy Might Not Exist What if the “missing” mass and energy that have haunted cosmology for decades are an illusion? What if the universe isn’t a frantic 13.8-billion-year-old rush of galaxies assembling in the dark, but a slower, more deliberate 26.7-billion-year-old process? That’s the claim of the CCC+TL model (covarying coupling constants plus tired light), and a new University of Ottawa study shows it is surviving some of the toughest tests cosmology can throw at it. A different set of rules Rajendra Gupta and postdoctoral researcher Nikolaos Samaras didn’t just tweak the standard ΛCDM model. They rebuilt the relevant equations from the ground up. In their framework, the fundamental constants that govern how forces and particles interact slowly change over cosmic time. The effects we normally attribute to invisible dark matter and mysterious dark energy emerge from those evolving constants instead. Decades of searches have failed to detect dark matter or dark energy directly. At the same time, the James Webb Space Telescope keeps finding surprisingly mature, massive galaxies in the very early universe—objects that seem to have formed too quickly under standard timelines. CCC+TL offers a single mechanism that could address both problems. Passing the tests The model has now been checked against several major pillars of cosmology: - Big Bang nucleosynthesis: It correctly predicts the observed abundances of hydrogen, helium, and other light elements formed in the first minutes after the Big Bang, matching the standard model’s success here. - Cosmic chronometers: Using the ages of galaxies to measure how fast the universe has expanded, the model agrees with the data. - Galaxy rotation curves: Applied to all 175 galaxies in the SPARC database, it reproduces their rotation speeds without any dark matter. - Bullet Cluster: The extra gravitational effect tracks the galaxies rather than the hot gas—consistent with the model’s predictions (though the researchers call this an early proof-of-concept). - Supernova time dilation: A separate study (still under review) also supports the framework. Gupta notes that most alternative models explain only a narrow set of observations. This one, he says, holds up across multiple independent tests—including a cosmic microwave background analysis that is still in preparation. Why early galaxies suddenly make sense In the standard model, the universe was only about 300 million years old at the epoch we call “cosmic dawn.” Under CCC+TL, the same observed redshift corresponds to a universe that is already about 4.6 billion years old. That extra time gives galaxies far longer to grow. In the researchers’ calculations, early galaxies come out roughly 12 times larger in size and mass than ΛCDM predicts. “Impossible early galaxies become predictable galaxies,” Gupta says. The model further predicts that galaxies should exist well beyond the distances JWST has currently reached. The telescope’s upcoming GLIMPSE program, which will hunt for objects at redshifts possibly exceeding 50, could put that prediction to a direct test. Where the standard model struggles to find enough time, CCC+TL has no such limit. A challenge to the standard picture The work doesn’t claim to have overturned ΛCDM. It does argue that a consistent alternative exists—one that removes the need for undetected dark components and simultaneously eases the tension created by unexpectedly mature early galaxies. Whether the broader community will accept the more complicated mathematics remains to be seen, but the model has now cleared several of the high bars any serious contender must clear. As Gupta puts it: the success should encourage astronomers to take the new model seriously. It is challenging to understand and apply, but it may extend the physics of the universe beyond the limits of the current standard framework. (Based on research by Rajendra P. Gupta et al., published in *Universe*, 2026, and related papers.)

NASA’s Bold Shortcut to Mars: Twin Probes Just Pulled Off a First-of-Its-Kind Gravity Slingshot Two small NASA spacecraft have spent the past year looping through a long, bean-shaped “holding pattern” around the Sun. Now they’ve swung back past Earth, fired their engines at the closest possible point, and are finally on a direct path to Mars — using a maneuver no previous NASA mission has ever attempted. The probes are ESCAPADE (Escape and Plasma Acceleration and Dynamics Explorers). Their job is to study how the solar wind interacts with Mars’s thin upper atmosphere and how the planet’s magnetic fields and plasma behave. They launched in November 2025 aboard Blue Origin’s New Glenn rocket, but they missed the ideal 2024 launch window because the rocket wasn’t ready. Instead of waiting another 26 months for the next favorable alignment of Earth and Mars, mission planners invented a detour. They sent the twins onto a large, looping trajectory that brought them back to Earth’s neighborhood in early November 2026. Then came the critical step: each spacecraft had to perform a precise engine burn while deep inside Earth’s gravitational field. The idea is a hybrid of a classic gravity assist and a powered flyby — the planet’s gravity bends and accelerates the trajectory, and the thrusters add extra speed at the exact moment it counts most. The first probe fired on November 7, the second on November 9. Both burns were flawless. “No NASA mission has ever done anything like this before,” said Rob Lillis, the mission’s principal investigator at UC Berkeley. “For most missions it’s simply not necessary.” Asal Naseri, acting deputy flight director for NASA’s Heliophysics Division, added: “For the first time NASA has used a powered Earth flyby to boost a spacecraft toward Mars. And we did it twice, only two days apart, perfectly.” By accepting a longer, more complicated path and then using Earth itself as a launchpad, the team turned a delayed rocket into an opportunity to test a new way of reaching the Red Planet. The two probes are now on course and expected to arrive at Mars in the coming years to begin mapping the invisible forces that shape its atmosphere. The maneuver shows how mission designers can still find creative routes when launch windows close — turning Earth’s gravity and a carefully timed engine burn into a second chance.

Galaxies of the Universe In the universe, every galaxy is unique and unlike any other. 🌌

The Ring Was Real: Independent Reanalysis Confirms the Famous Black Hole Image In April 2019, the Event Horizon Telescope (EHT) collaboration released the first-ever image of a black hole — a glowing orange ring surrounding a dark shadow at the center of the galaxy M87, about 55 million light-years away. It wasn’t a conventional photograph. It was a reconstruction built from sparse radio signals collected by telescopes scattered across the planet. Hot gas spiraling into the supermassive black hole shines in millimeter radio waves, while the black hole’s gravity bends light paths, forming a bright ring around the event horizon. The image became one of the strongest observational tests of Einstein’s general relativity in extreme gravity. Years later, doubt appeared. Independent teams, notably Japanese researchers led by Makoto Miyoshi, reprocessed the publicly available EHT data in 2022 and 2024. By changing processing settings and widening the field of view, the ring vanished. In its place they recovered an elongated bright spot and scattered clumps. Critics suggested the iconic ring might have been an artifact — the result of algorithms that were given a preferred size and shape from the start, plus a narrow search window that suppressed other possibilities. Why a Black Hole “Photo” Is Always a Reconstruction M87* is tiny on the sky: roughly 40 microarcseconds across. Observing it at the 1.3 mm wavelength used by the EHT would require a single telescope the size of Earth. Instead, astronomers link existing radio observatories on different continents (Chile, Mexico, Hawaii, Spain, and later others) into one virtual Earth-sized telescope. Each pair of antennas captures only a narrow slice of information — specific spatial frequencies. With so few telescopes, most of the information about the object’s appearance is missing. Atmospheric water vapor further distorts the signals. From the same sparse, noisy measurements it is mathematically possible to reconstruct a clean ring, an elongated blob, or streaks. Classical imaging algorithms start with a template (a fuzzy blob of the expected size) and iteratively adjust both the image and atmospheric corrections. Change the template size or the field of view and the result can shift dramatically. That sensitivity is exactly what the critics exploited. How the Australian Team Settled the Debate Researchers from CSIRO and ICRAR (Samuel Lai, Nithyanandan Thyagarajan, Ivy Wong, Foivos Diakogiannis and colleagues) developed a fully independent imaging pipeline. Their results appeared in *Nature*. The first key step was to abandon ordinary pairwise measurements and switch to **closure invariants**. By grouping the telescopes into closed triangles, atmospheric delays and instrumental gain errors cancel out mathematically. What remains is information about the object’s shape that is protected from the usual calibration uncertainties. They then fed these cleaned measurements into a neural network called **GenDIReCT**. It is a diffusion model: it starts from pure noise and gradually “reveals” an image, constrained at every step by the real radio data. Crucially, the network was trained mainly on ordinary everyday photographs (animals, vehicles, household objects from the CIFAR-10 dataset) plus simple geometric shapes — not on simulated black holes. The goal was to avoid teaching the model “black holes look like rings.” A second, purely mathematical Bayesian geometric method (no neural network) produced matching results. What the New Analysis Found - Across all eight observing days in 2017, 2018, and 2021, both methods recovered a compact ring with an average diameter of **42.2 ± 1.5 microarcseconds**. - The ring remains stable even when the field of view is expanded far beyond the point where earlier critical analyses saw it disappear. - The critics’ ring-free images are explained by incomplete or noisy data on certain days (for example, 5 April 2017) and by the temporary loss of a key telescope (the large LMT in Mexico on 25 April 2018). On the best days the ring is robust regardless of field-of-view size. The measured diameter implies a black-hole mass of **6.5 ± 0.5 billion solar masses**, consistent with stellar-dynamics estimates and ruling out the significantly lower mass previously inferred from gas kinematics. The ring is also asymmetric — brighter on the southern and southwestern side — as expected from the relativistic Doppler boost of plasma orbiting at near-light speed.

Gravity That Can Snap and Reconnect: A Hidden Surprise in Einstein’s Equations Gravity feels like the most reliable force in the universe. It keeps our feet on the ground, steers planets in their orbits, and shapes entire galaxies. Yet new calculations suggest it may have a dramatic, almost rebellious side: under the right conditions, the mathematical structures that describe gravitational fields can break their existing connections and snap together in entirely new arrangements. Physicists Luca Comisso of Columbia University and Felipe Asenjo of Adolfo Ibáñez University in Chile found this possibility without inventing any new laws of physics. They simply looked at Albert Einstein’s century-old equations of general relativity from a fresh angle. The Solar Analogy To grasp what they mean, think about the Sun. Its powerful magnetic fields thread through the hot plasma of the corona. Most of the time those field lines stay intact even as the plasma churns and twists. But sometimes the lines snap and reconnect in a different pattern. The process, called magnetic reconnection, releases enormous amounts of stored energy and drives the explosive solar flares we observe. Comisso and Asenjo asked a natural question: if Einstein’s equations can be rewritten in a form that closely resembles the equations of electromagnetism and plasma physics, could gravity do something similar? Sheets Instead of Lines In their earlier work they showed that gravitational fields can preserve certain connections between regions of spacetime, much like magnetic fields frozen into plasma. When those “frozen-in” conditions break down, something new becomes possible. Instead of simple lines, they describe the gravitational field as sheets—mathematical surfaces stretching through four-dimensional spacetime (three dimensions of space plus time). These sheets are not physical objects you could touch; they are a way of visualizing how the field links different regions. As spacetime evolves, the sheets can stretch, bend, and, under specific conditions, sever their old connections and form new ones. The researchers call this gravitational reconnection. Importantly, spacetime itself does not tear. What changes is the connectivity of the gravitational field, and with that change energy can flow from the field into matter. Why It Matters Modern supercomputers can simulate black-hole mergers and stellar collapses in exquisite detail, yet even the most complete simulation does not always reveal the precise mechanisms that transfer energy and momentum. Magnetic reconnection gave solar physicists a clear explanation for why certain configurations suddenly release huge amounts of energy. Gravitational reconnection may offer a similar conceptual key for extreme gravity. The process could, in principle, leave detectable imprints in the gravitational waves produced by colliding black holes or collapsing stars. If numerical models can identify those signatures, existing detectors such as LIGO, Virgo, and KAGRA might one day search for them. For now the result remains theoretical: the equations allow gravitational reconnection, but astronomers have not yet confirmed that it actually happens in nature. Still, the work is a reminder that even after more than a hundred years, Einstein’s equations continue to hide unexpected behaviors—waiting for someone to ask the right question.

A giant solar prominence above the surface of our star, July 12, 2023

Martian wasteland, as seen by the Perseverance rover

Silent Deaths of Stars: How the Universe Creates Black Holes Without Fireworks Most massive stars end their lives with a deafening explosion. The core collapses, a shockwave blasts outward, and for a moment the star outshines an entire galaxy. What’s left is a neutron star or a black hole, while most of the star’s material is hurled into space. But some stars appear to have a very different ending. They simply… vanish. No flash, no shockwave, no bright farewell. The star quietly collapses under its own gravity and turns into a black hole. Astronomers have long suspected that such “failed supernovae” exist, but they are almost impossible to catch: there is no bright event for ordinary telescopes to see. Now gravitational waves have given us an indirect clue. ### A Strange Gap in Masses A team led by Isaac Legred and Katerina Chatziioannou analyzed 257 black hole mergers detected by the LIGO–Virgo–KAGRA network over ten years. Gravitational waves allow fairly accurate estimates of the masses and spin rates of the colliding objects. The picture was unexpected. About three-quarters of all the black holes in this sample have a mass of roughly ten times that of the Sun. But in the range from 12 to 16 solar masses there are noticeably fewer objects — almost a gap. Such a clear break in the distribution had not been highlighted before. “We constantly see mergers of black holes with masses around ten solar masses. But why, for example, are objects of 14 solar masses so rare?” says Legred. A Shared Origin? Black holes around ten solar masses have another common feature: their spin rates are concentrated in a narrower range than the rest of the sample. This suggests they may have formed in the same way. The researchers believe this population could have been born from exactly these “quiet” collapses. When the shockwave inside the star does not gain enough energy to blow off the outer layers, almost all the material falls back onto the core. The star disappears, leaving behind a black hole of about ten solar masses. “The vast majority of merging black holes in the Universe have a mass roughly ten times that of the Sun. Our data show that this group may share a common origin. They may form a separate population of objects that appeared after failed supernovae,” says Chatziioannou. Still Only a Hint The authors emphasize that this is not yet proof. Direct observations of “quiet” stellar deaths are still almost nonexistent (though individual cases, such as a vanished star in Andromeda, are already being discussed). But the statistics of masses and spins from gravitational waves match well with what models of failed supernovae predict. If the hypothesis is confirmed, it would mean that a significant fraction of stellar black holes in the Universe are born not in the roar of an explosion, but in silence. The star simply fades — and a black hole remains in its place.

Chandra has unmasked a "false supernova," AT 2016blu ✨ It is not a terminal explosion, but rather an "imposter" star. Located in the spiral galaxy NGC 4559—about 30 million light-years away—this luminous blue variable (with a mass of ~33 Suns) flares up and fades while remaining intact, which is why it is often mistaken for a supernova. New data from the Chandra X-ray Observatory has detected the object in X-rays for the first time, revealing the underlying mechanism: a companion star in an elongated orbit triggers these outbursts whenever it draws near. Between 2012 and 2026, 27 such flares were recorded, occurring with a period of approximately 113 days—a behavior not characteristic of supernovae.

Comets likely did not deliver the "building blocks of life" to Earth New research by a team led by Richard Anslow (University of Cambridge) models the entry and impact of comets, showing that their organic material almost always vaporized. For such molecules to survive, the impact velocity would need to be below ~15 km/s; however, actual comets travel faster and typically strike at steep, oblique angles. Such "successful" delivery events would be extremely rare. It is more probable that pre-biological chemistry either emerged independently on Earth or that these molecules were brought by asteroids—for instance, the building blocks of RNA have been discovered on the asteroid Bennu. On Mars, the chances of such molecules surviving would be higher, owing to the planet's thin atmosphere.

The Bright Edges of a Black Hole’s Jet: Plasma Simulations Finally Match Centaurus A Twelve million light-years away, the supermassive black hole at the heart of Centaurus A is blasting two colossal jets of plasma into space at nearly the speed of light. In ordinary intuition a jet should shine brightest down its middle, yet the Event Horizon Telescope has shown the opposite: Centaurus A’s jets glow most strongly along their edges while the core stays comparatively dark. For decades the reason remained unclear. A team at the University of Würzburg has now reproduced the pattern with high-resolution plasma simulations. Centaurus A is the nearest active galaxy to Earth and its central black hole weighs roughly 60 million solar masses, so its jets can be studied in exceptional detail. The researchers combined three-dimensional general-relativistic magnetohydrodynamic (GRMHD) simulations of a magnetically arrested accretion disk and the jets it launches with radiative-transfer calculations that include realistic plasma physics. The key lies in the way fast electrons move inside the jet’s powerful magnetic fields. Their radiation depends on the orientation of the field lines. Because the magnetic structure of the jet is helical and complex, electrons along the edges emit more brightly than those nearer the axis—exactly the limb-brightened appearance seen by the EHT at 1.3 mm wavelength. “Cen A is our closest window into the physics of relativistic jets,” said master’s student Felix Glaser, lead author of the study published in *Astronomy & Astrophysics*. “The fact that our plasma-informed model reproduces the observed edge brightening suggests we are capturing an important piece of the underlying physics. These processes may not be unique to Centaurus A, but could be common in relativistic jets throughout the universe.” What makes the result striking is the leap in scale. Microscopic plasma effects—how individual particles gyrate and radiate along magnetic field lines—shape structures that stretch across light-days. The same simulations also match the detailed EHT images, including both total intensity and polarization. Dr. Christian Fromm, who leads the Computational Astrophysics Group, noted: “Microscopic plasma effects can shape structures on vastly larger scales. Future observations will reveal even more of these plasma signatures, making it increasingly important to include realistic plasma physics in our models.” The work also illustrates the approach of the DFG Research Unit “Relativistic Jets in Active Galaxies,” which unites high-resolution observations, numerical simulations, and plasma theory. As new millimeter telescopes come online and arrays such as the next-generation Very Large Array and the Square Kilometre Array deliver sharper data, models that treat the plasma realistically will become essential for understanding how black holes accelerate particles to extreme energies and how those particles light up the jets we observe.