(C) Daily Kos This story was originally published by Daily Kos and is unaltered. . . . . . . . . . . Top Comments: Was a Dark Matter Particle Detected? [1] ['Bill In Portland Maine', 'Sabrina Haake', 'Greg Dworkin'] Date: 2026-09-04 Here at Top Comments we strive to nourish community by rounding up some of the site’s best, funniest, most informative commentary, and we depend on your help!! Here’s how to submit nominations in DK6: If you see a comment by another Kossack that deserves wider recognition, please send it either to topcomments at gmail dot com or via kosmail to topcomments- either search for user @topcomments, or click that link then click “send message”!) by 9:30pm Eastern for inclusion in that day’s diary. Please, please include a few words about why you sent it in as well as your user name (even if you think we know it already :-)), so we can credit you with the find! It’s especially helpful if you include a link to the comment you’re nominating… hover over the comment and you’ll see Share and Report options. Click Share, then choose ”copy url” and paste that into your message to us. Anybody who has read my diaries over the years knows that I am extremely curious about dark matter. When the speed of stars rotating around the centers of galaxies was measured, it was clear that the visible matter in the galaxy was nowhere near enough to account for those speeds, so it was deduced that the motions of the stars were influenced by matter that we couldn’t see, that is, dark matter. Further, in order to explain the observed dynamics, it was determined that dark matter must make up about 80% of all matter, meaning that the stuff that makes up our planet, our Sun, our furniture, and ourselves is actually a minor portion of the total amount of matter in the universe. Particle physicists became excited about the possibility of finding a whole new class of as-yet unknown dark matter particles that are not predicted by the Standard Model, and so discover new physics. Physicists have been searching for evidence of dark matter particles for decades now, by various means. Using particle accelerators, they have looked for new particles at high energies, looking for new and unusual particles, but with no success. The other broad strategy is to place a large vessel full of a cold liquid or solid deep underground, and then look for a flash of light that is caused by a collision of a passing particle of dark matter with atoms in the vessel. [I interject here to address a question that may occur to you: If dark matter only interacts with ordinary matter through gravity, by what means could there ever be a collision? I can’t answer that question, but apparently, physicists have somehow deduced that such collisions can occur, though only very rarely.] So there are many tons of such liquids and solids armed with light detectors where physicists watch patiently for a flash that they can’t explain using known physics. Again, decades have passed without observing any such event… …Until now. In June of 2023, a single event observed in what’s called the LUX-ZEPLIN (LZ) Experiment buried a mile below the surface of South Dakota. The large quantity of liquid is made up of the element xenon, one of the noble gases. If the anomalous event was caused by dark matter, the WIMP that generated it would likely have a mass of at least 200 GeV/c2 (gigaelectronvolts), or more than 200 times the mass of a proton. The LZ results have not reached “5-sigma” significance, the statistical threshold in physics that an event must reach to be considered a discovery. The new analysis is 2.6 sigma, meaning there is approximately a 0.5% chance that the event could be explained by known backgrounds. With additional data, researchers can test whether the finding continues to grow in significance or fades away. LZ has already accumulated the world’s largest dark matter dataset and will continue to accrue WIMP search data at SURF, substantially improving their search statistics. It should come as no surprise that this observation is not definitive. It’s dangerous to build a theory on a single event. There need to be lots of them to take this as a serious advance, and given that in decades of looking, we’ve seen exactly one. Maybe. However, if this observation was of a dark matter particle, physicists will have a better idea of what to expect from possible such events to be observed in the future. Given the rate of observations, I may not live to see the next one, but I can hope that we’ll know something more definitive about dark matter, say, by the end of this century. Maybe. On to the Comments: No nominations tonight. [END] --- [1] Url: https://www.dailykos.com/stories/2026/9/4/800094262/community/top-comments-was-a-dark-matter-particle-detected/ Published and (C) by Daily Kos Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified. via Magical.Fish Gopher News Feeds: gopher://magical.fish/1/feeds/news/dailykos/