{"id":831400,"date":"2026-05-30T02:44:23","date_gmt":"2026-05-30T02:44:23","guid":{"rendered":"https:\/\/www.europesays.com\/us\/831400\/"},"modified":"2026-05-30T02:44:23","modified_gmt":"2026-05-30T02:44:23","slug":"is-dark-energy-unnecessary-mathematicians-challenge-standard-cosmological-model-of-universe","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/831400\/","title":{"rendered":"Is Dark Energy Unnecessary? Mathematicians Challenge Standard Cosmological Model of Universe"},"content":{"rendered":"

Mathematicians from University College London and the University of California, Davis, have published a mathematical proof that the Universe\u2019s accelerating expansion can be explained without dark energy, dealing a serious blow to the Lambda-cold dark matter model \u2014 the standard cosmological model that has stood for nearly 30 years.<\/strong><\/p>\n

\"Alexander<\/p>\n

Alexander et al. provide a mathematical proof that instabilities inherent in the Einstein-Euler equations imply that the current model of the expanding Universe is not viable. Image credit: M. Weiss \/ Harvard-Smithsonian Center for Astrophysics.<\/p>\n

Almost 30 years ago, dark energy was proposed as the force responsible for the accelerating expansion of the Universe.<\/p>\n

The idea harkens back to Albert Einstein\u2019s original 1915, gravity-describing equations for general relativity.<\/p>\n

To produce a static universe, Einstein initially introduced an antigravity factor in his theory. He called this factor the cosmological constant.<\/p>\n

After Edwin Hubble discovered the Universe was expanding in 1929, Einstein famously called the cosmological constant his \u2018biggest blunder\u2019 because without it he could have predicted the expansion.<\/p>\n

However, the cosmological constant, and the idea that it\u2019s interchangeable with dark energy, was reintroduced to explain the Universe\u2019s accelerating expansion in the 1990s.<\/p>\n

\u201cThe Friedmann family of spacetimes has been the starting point for modern cosmology since Lemaitre and Hubble first formulated the theory of an expanding Universe of galaxies emanating from an initial Big Bang singularity,\u201d said University of California, Davis Professor Blake Temple and colleagues.<\/p>\n

\u201cThe theory is based on the explicit solutions of Einstein\u2019s field equations discovered by Alexander Friedmann in the early 1920s.\u201d<\/p>\n

\u201cAs the story goes, in 1922 Friedmann sent his solutions to Einstein, who initially rejected them believing the Universe was static but shortly thereafter accepted them as correct under appeal by Friedmann.\u201d<\/p>\n

\u201cBy 1931, Einstein rejected the static model as unstable and accepting Hubble\u2019s 1929 measurement of the expanding Universe, is famously quoted as describing Lemaitre\u2019s cosmology based on Friedmann spacetimes as the most beautiful and satisfactory explanation of creation.\u201d<\/p>\n

\u201cIn our new paper, we give a theorem stating that the Friedmann spacetimes are in fact all unstable to radial perturbation, at every order.\u201d<\/p>\n

Professor Temple and co-authors pursued alternative explanations for the accelerating expansion of the Universe.<\/p>\n

\u201cOur first idea was that maybe the Universe was expanding because there was a shockwave, and the anomalous acceleration was the expanding wave behind that shockwave,\u201d Professor Temple said.<\/p>\n

\u201cThen we realized there\u2019s a family of self-similar solutions during the radiation epoch of the Big Bang, which might model that expanding wave.\u201d<\/p>\n

Self-similar equations describe physical phenomena that maintains a pattern or structure, regardless of its scale.<\/p>\n

In their paper, the mathematicians use a self-similar version of the Einstein equations, which they derived in prior work, to represent the standard model of cosmology as a rest point of the equations.<\/p>\n

This provides the framework for a complete mathematical characterization of the standard model\u2019s stability, and more generally, the stability all Friedmann spacetimes during the matter-dominated epoch of the Big Bang.<\/p>\n

\u201cWe prove that, like Einstein\u2019s static model, the Friedmann spacetimes are all unstable to radial perturbation at large length scales,\u201d Professor Temple said.<\/p>\n

\u201cThis appears to rule out the Lambda-cold dark matter model as a viable stable solution of the Einstein equations of general relativity, with or without dark energy.\u201d<\/p>\n

\u201cThis means that the Big Bang should generically look exactly like a Friedmann spacetime near the center of symmetry, but generically one should observe accelerations away from Friedmann far from the center.\u201d<\/p>\n

The researchers found that the accelerating expansion of the Universe is a direct consequence of the Einstein-Euler equations without the insertion of a cosmological constant or dark energy.<\/p>\n

The math also calls into question the Copernican principle \u2014 the idea that the Earth\u2019s location does not occupy a special place in the Universe.<\/p>\n

\u201cBoth the Lambda-cold dark matter model and a spherically symmetric spacetime produce a special place where we must lie for the model to be physically plausible,\u201d Professor Temple said.<\/p>\n

\u201cIf this principle rules out one, it has to rule out the other.\u201d<\/p>\n

The paper<\/a> was published this week in the Proceedings of the Royal Society A.<\/p>\n

_____<\/p>\n

C. Alexander et al. 2026. The instability of critical and underdense Friedmann spacetimes at the Big Bang as an alternative to dark energy. Proc. A 482 (2338): 20250912; doi: 10.1098\/rspa.2025.0912<\/p>\n","protected":false},"excerpt":{"rendered":"Mathematicians from University College London and the University of California, Davis, have published a mathematical proof that the…\n","protected":false},"author":3,"featured_media":10200,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[25],"tags":[18187,234788,6570,341101,202893,492,159,11175,111014,67,132,6747,68],"class_list":["post-831400","post","type-post","status-publish","format-standard","has-post-thumbnail","category-physics","tag-big-bang","tag-cold-dark-matter","tag-dark-energy","tag-friedmann-spacetimes","tag-hubble-constant","tag-physics","tag-science","tag-space-time","tag-standard-model","tag-united-states","tag-unitedstates","tag-universe","tag-us"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/116661234505677143","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/831400","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=831400"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/831400\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/10200"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=831400"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=831400"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=831400"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}