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Fresh distance measurements from the Dark Energy Spectroscopic Instrument (DESI<\/a>) revealed a small mismatch in results<\/a> that otherwise track cosmic history well.<\/p>\n Targeting that tension, Muhammad Ghulam Khuwajah Khan at Indian Institute of Technology Jodhpur, (IIT Jodhpur<\/a>) built a model adding drag.<\/p>\n In a new preprint, Khan at IIT treated expanding space as something that resists stretching, then eases off later.<\/p>\n If the tension holds up, the next step is to explain what kind of physical resistance empty space could have.<\/p>\n What viscosity changes<\/p>\n Resistance in empty space would oppose expansion, making the universe a bit \u201cstickier\u201d than a perfect vacuum.<\/p>\n Physicists call this bulk viscosity<\/a>, resistance to volume change during expansion, and it shows up as extra pressure.<\/p>\n Bulk viscosity pushes back only when space changes size, so faster expansion produced more pressure than slower expansion.<\/p>\n That makes viscosity tempting as a patch for cosmic data, but calling space a \u201csticky fluid\u201d still demands a real cause.<\/p>\n Dark energy assumptions<\/p>\n Most cosmology models explain the universe\u2019s speeding-up by adding a smooth ingredient that behaves the same everywhere.<\/p>\n Cosmologists call it dark energy<\/a>, an unknown source of pressure that speeds cosmic expansion, even as matter pulls inward.<\/p>\n For decades, many analyses assumed this push stayed constant over time, so one number could describe it.<\/p>\n That constant option is the cosmological constant, a fixed energy in empty space, and the tension pressures it.<\/p>\n Space can vibrate<\/p>\n To create that turning-on pressure, Khan gave space an internal way to wobble as it expanded. In materials science, phonons, collective vibrations moving through a solid, carry energy<\/a> without carrying matter.<\/p>\n Khan extended that idea to the vacuum, describing longitudinal ripples that travel through space and create resistance.<\/p>\n As those ripples respond to expansion, the model links small-scale motion inside space to the large-scale speed of galaxies.<\/p>\n When drag turns<\/p>\n Drag in Khan\u2019s universe did not run at full strength forever, and his equations made it temporary.<\/p>\n Instead, pressure lagged behind expansion by a built-in delay, so the resistance peaked during certain eras.<\/p>\n Early on and far in the future, the model settled back toward a near-constant behavior, leaving only a mid-era increase.<\/p>\n Such a time-windowed effect can mimic a changing acceleration, but it also makes the idea easy to falsify.<\/p>\n Matching the pattern<\/p>\n DESI\u2019s strongest clues come from a repeating separation pattern in galaxies, which provides a standard distance scale for cosmic maps.<\/p>\n Cosmologists call that signal baryon acoustic oscillations, a leftover pattern from early-universe sound waves, and DESI measured it across time.<\/p>\n At IIT, the team tuned his fluid equations until that scale landed where DESI saw it, across several eras.<\/p>\n Because the model chased observations rather than building from particle physics, it stands or falls on future surveys.<\/p>\n Predictions in data<\/p>\n Other sky measurements track expansion in different ways, and a viscous universe<\/a> would need to agree with them too.<\/p>\n Supernova distance markers and the growth of galaxy clusters both respond to the expansion rate, so drag changes both.<\/p>\n Light bending by gravitational lensing, warping of images by mass, also depends on how structure grows under drag.<\/p>\n Failing any one of those cross-checks would leave viscosity as a clever curve-fit, not a property of space.<\/p>\n Limits of the idea<\/p>\n Caution matters here because Khan posted the work before peer review, and the idea could fail basic checks.<\/p>\n In ordinary fluids, viscosity comes from particles exchanging momentum, so an empty vacuum needs a believable source.<\/p>\n A recent paper<\/a> laid out how bulk viscosity models can run into internal contradictions when tuned too hard.<\/p>\n Until a physical mechanism explains the drag and other datasets agree, the model remains an interesting placeholder.<\/p>\n Yes. You can keep the focus on the test rather than the instruments. Here is a cleaner version that avoids naming multiple telescopes:<\/p>\n New model for universe expansion<\/p>\n More observing time will decide whether the tension survives, and the next decade offers the clearest verdict.<\/p>\n Ongoing galaxy surveys will keep measuring how fast space<\/a> expands across different eras of cosmic history. Future maps of billions of galaxies will show whether the expansion truly changes in the way a viscous model predicts.<\/p>\n If those independent measurements line up, the case for cosmic drag strengthens, but if they conflict, the idea likely fades.<\/p>\n Khan\u2019s model turns an abstract mismatch into a clear claim that empty space pushes back when it expands.<\/p>\n If upcoming galaxy<\/a> surveys confirm the same drag pattern, cosmologists may replace a fixed dark energy picture with a time-changing one, though only after careful checks.<\/p>\n The study is published in arXiv<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"A new physics model attempts to explain puzzling measurements of how fast galaxies are moving away from us,…\n","protected":false},"author":2,"featured_media":428418,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[2302,90,56,54,55],"class_list":{"0":"post-428417","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-physics","9":"tag-science","10":"tag-uk","11":"tag-united-kingdom","12":"tag-unitedkingdom"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/428417","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=428417"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/428417\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/428418"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=428417"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=428417"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=428417"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}