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Close Menu Facebook X (Twitter) Instagram Biology Chemistry Earth Health Physics Science Space Technology Facebook X (Twitter) Pinterest YouTube RSS Home » Space » Galaxies May Be Mimicking the Dark Matter Signals Astronomers Have Been Hunting Space Galaxies May Be Mimicking the Dark Matter Signals Astronomers Have Been Hunting By William Poor, University of Washington September 2, 2026 2 Comments 5 Mins Read Facebook Twitter Pinterest Telegram LinkedIn WhatsApp Email Reddit Share Facebook Twitter LinkedIn Pinterest Telegram Email Reddit Most galaxies are likely surrounded by long filaments of orbiting stars known as stellar streams. In a new study from the University of Washington, astronomers simulated stellar streams — pictured here as multicolored streaks — as they orbited virtual host galaxies to test a leading theory about how dark matter might influence the streams’ shape. The results could help researchers separate true evidence of dark matter from false positives. Credit: Visualization by Arpit Arora and Adrian Price-Whelan. Milky Way image credit: Stefan Payne-Wardenaar Galaxies can create many of the same stellar stream distortions that astronomers have looked to as possible signs of dark matter. Astronomers have long hoped that gaps, bends, and other distortions in long bands of stars around the Milky Way could reveal the hidden influence of dark matter. But new simulations suggest many of those features can arise from the galaxy itself, even without the small dark matter clumps thought to produce them. University of Washington researchers modeled roughly 15,000 of these bands, known as stellar streams, across four Milky Way-sized galaxies. The simulations omitted small dark matter clumps called subhalos. After five billion simulated years, irregularities appeared in nearly every stream, and only 70 remained perfectly smooth. “In our simulations, the host galaxies alone caused the same kinds of irregularities that we observe in real stellar streams,” said lead author Arpit Arora, a UW postdoctoral scholar in astronomy. “Now that we can predict what the host galaxy does on its own, we can start isolating the part that dark matter is responsible for.” The study was published in The Astrophysical Journal . Galaxies alone can disrupt stellar streams The distortions arose from the structure of the galaxies themselves. Stars were distributed somewhat unevenly across each simulated disk, creating regions of greater and lesser density similar to those in a real galaxy. As stellar streams passed through denser areas, the uneven gravitational landscape bent and tore at them. Arora had expected the galaxies to produce some irregularities, but not nearly so many. “We found that almost all of the streams had some sort of structural variation,” Arora said. “So this idea that streams are naturally thin and smooth wasn’t really necessarily true.” The simulations produced wiggles, kinks, spurs, branches, gaps, and clumps. Some streams were completely torn apart by the gravitational froth of their host galaxies. Those orbiting closer to the galactic core encountered dense, clumpy regions more often and developed more irregularities. Stream irregularities may have another source The result complicates efforts to use stellar streams to investigate dark matter, a theorized substance that does not interact with light or normal matter except through gravity. “Dark matter makes up most of the mass in the universe and forms the scaffolding that galaxies grow on, but we still don’t know what it is,” said co-author Nora Shipp, a UW assistant professor of astronomy. “The Milky Way is one of the best laboratories we have for figuring that out, and stellar streams are one of the sharpest tools inside it.” A selection of virtual stellar streams shows the variety of bends, wiggles, kinks and gaps that the simulations produced. Out of roughly 15,000 streams, only 70 were featureless. Credit: Arora et. al/The Astrophysical Journal Most stars in the Milky Way lie in a relatively flat plane, while stellar streams follow different paths around the galaxy. A stream forms when a group of stars crashes into a galaxy and becomes trapped by its gravity. As the stars orbit, the galaxy stretches the cluster into a long, thin filament . Most galaxies host stellar streams, though those around the Milky Way are the most visible to astronomers. Many stellar streams in our galaxy contain gaps and kinks. Astronomers have proposed that some of these features could result from encounters with dark matter subhalos. If so, their distortions could provide information about the composition of dark matter. The new simulations show that astronomers must first account for similar features produced by the host galaxy itself. Dark matter fingerprints remain to be isolated Arora now plans to add dark matter clumps to future simulations and test whether they create patterns that can be distinguished from those caused by the galaxy alone. New observations could help make that distinction. The Simonyi Survey Telescope at the NSF-DOE Vera C. Rubin Observatory is expected to discover many more stellar streams in the Milky Way. Those observations could help astronomers classify stream features and search for signatures that can be more confidently linked to dark matter. “Sadly there’s no magic wand to reveal the structure of dark matter,” said James Davenport, a research assistant professor of astronomy at the UW. “Streams are complex systems, but they’re still the most interesting way to study the dark matter close to home.” Reference: “No Stream Left Unscathed: The Imprint of a Host Galaxy” by Arpit Arora, Peter S. Ferguson, Jacob Nibauer, Nora Shipp, Videep Reddy, Eugene Vasiliev, Jack Kohm, Laurella C. Marin, Adrian M. Price-Whelan, Denis Erkal, Sarah Pearson, Andrew Wetzel, Jeremy Bailin and Robert Feldmann, 27 August 2026, The Astrophysical Journal . DOI: 10.3847/1538-4357/ae89af This research was funded by the Gordon and Betty Moore Foundation. Never miss a breakthrough: Join the SciTechDaily newsletter. 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Facebook Twitter Pinterest LinkedIn Email Reddit Related Articles Dark Matter Dynamics: Exploring the Strange Milky Way Satellite, Crater 2 Galactic Surprise: Milky Way’s Slower Outer Stars Suggest Dark Matter Overestimated Dark Matter and Galactic Collisions: Harvard Astronomers Explain the Milky Way’s Mysterious Warp Strange Galactic Signal Coming From the Center of the Galaxy Has Potential New Explanation Ancient Dwarf Galaxy Shredded in a Collision With the Milky Way May Help in Search for Dark Matter Strangely Massive Black Hole Discovered in Milky Way Satellite Galaxy Dark Matter “Counterweight” Is Slowing the Spin of the Milky Way’s Galactic Bar New All-Sky Map of Milky Way’s Outer Reaches Released – Could Offer a New Test of Dark Matter Theories Milky Way’s Dark Side Revealed by Measurements of Pulsar Acceleration 2 Comments Ralph Johnson on September 2, 2026 2:00 pm For decades, mainstream astrophysics assumed that gaps, kinks, and bends in stellar streams were “fingerprints” left behind by collisions with invisible dark matter. New research proves that ordinary galactic structures produce these exact same features on their own. This discovery highlights a recurring pattern in standard physics: when lower-dimensional or incomplete models fail to explain structural irregularities, science invents invisible placeholders rather than re-examining internal geometry.By updating standard mass-energy assumptions to account for complete 3D rotational geometry ($E = mc^2 \cdot \pi$), these stream distortions are recognized not as chaotic anomalies caused by dark matter, but as the natural uncoiling of Vector Helical Trajectories ($V_h$) through variable spatial impedance ($Z_T$).Whether observing plasma in a tokamak, heat flow across a micro-chip, or stellar streams orbiting a galactic core, energy flow is governed by internal spatial geometry—not hypothetical external patches. The Link , take a look , https://docs.google.com/document/d/1iHSMitywAsr2YbvXBW65bAR9g5bELPSy1meMg_ik7f8/edit?usp=drive_link Reply Jojo on September 2, 2026 8:30 pm Anyone who believes that dark matter exists should be fired. Any grants to look for dark matter should be terminated. We need to put a cork in this subject. Reply Leave A Reply Cancel Reply Save my name, email, and website in this browser for the next time I comment. Facebook Twitter Pinterest YouTube Don't Miss a Discovery Subscribe for the Latest in Science & Tech! 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