This intriguing theory changes the geometry of spacetime itself and shows that acceleration can appear even when spacetime<\/a> contains no extra energy component.<\/p>\n The approach keeps the ingredients simple and rewrites the rules for measuring distance and time. <\/p>\n By deriving the large\u2011scale equations within this new setup, the authors show how the universe\u2019s accelerated expansion can arise without inserting a cosmological constant<\/a> into the equations where, in their opinion, it doesn\u2019t belong.<\/p>\n Understanding the Standard Model<\/p>\n Einstein\u2019s general relativity<\/a> links matter and geometry: mass and energy<\/a> curve spacetime, and that curvature guides motion. <\/p>\n Assuming the universe looks the same on large scales leads to the Friedmann equations, which track how the universe\u2019s scale changes with time.<\/p>\n To match the observed acceleration with those equations, cosmologists usually add a constant energy density, often called dark energy<\/a>. It fits the data well, but it extends the model by adding a separate ingredient.<\/p>\n How Finsler geometry differs<\/p>\n The study replaces the usual Riemannian geometry with Finsler geometry<\/a>. In the standard case, measured intervals do not depend on direction or on the state of motion. <\/p>\n In a Finsler spacetime, the metric can depend on both. This direction\u2011 and velocity\u2011dependent structure sits inside the definition of spacetime rather than outside it.<\/p>\n Working in that framework, the authors derive gravitational field equations and then obtain a cosmological analog of the Friedmann equations, the Finsler\u2013Friedmann equation. <\/p>\n It plays the same role as in standard cosmology but reflects the new metric\u2019s dependence on motion and direction.<\/p>\n Matter, geometry, and universe expansion<\/p>\n The treatment of matter changes, too. In general relativity<\/a>, gases and other many\u2011particle systems are summarized by an energy-momentum tensor built from the second moment of a one\u2011particle distribution function.<\/p>\n That summary discards higher moments that describe asymmetries and detailed structure.<\/p>\n Here, geometry and matter live on the same phase space (positions and velocities). Because the metric depends on direction and speed, higher moments naturally contribute to gravity. <\/p>\n The kinetic description stays intact instead of being reduced to a single, second\u2011moment summary. Matter and geometry impact the universe\u2019s expansion by being matched at the same level of detail.<\/p>\n Acceleration without dark energy<\/p>\n Solving the Finsler-Friedmann equation for a homogeneous and isotropic universe (it appears the same when looking in any direction) yields a vacuum solution with exponential growth of the scale factor<\/a>.<\/p>\n In the standard picture, that behavior requires a cosmological constant. In this construction, the acceleration arises from the geometry itself.<\/p>\n This is the central result: by allowing direction\u2011 and velocity\u2011dependent measurements, the expansion accelerates even when the average energy density carries no dedicated dark\u2011energy term.<\/p>\n Causality and local physics<\/p>\n Changing geometry raises questions about cause and effect. The causal structure appears in the shape of light cones, which determine which events can influence others. <\/p>\n The analysis shows only mild deformations of light cones<\/a> relative to the standard case. For observers and particles moving slowly with respect to the cosmic rest frame, the differences remain small.<\/p>\n That behavior helps preserve tested predictions of general relativity at ordinary speeds and scales. This framework offers a way to adjust the large\u2011scale expansion while keeping well\u2011known local physics intact.<\/p>\n Measuring universe expansion<\/p>\n The path forward relies on hard data. Supernova measurements compare brightness and distance to map the expansion history. <\/p>\n Galaxy surveys<\/a> measure a preferred scale set by baryon acoustic oscillations (a regular pattern in galaxy spacing).<\/p>\n The cosmic microwave background<\/a> records early\u2011universe geometry and contents. The growth of structure tracks how small density ripples became galaxies and clusters.<\/p>\n The Standard Model<\/a> performs well across these tests. A Finsler\u2011based model, as proposed in this study, must meet the same benchmarks.<\/p>\n It needs concrete predictions for distance-redshift relations, the BAO scale, the microwave background pattern, and the time dependence of structure growth. <\/p>\n Gravitational lensing<\/a> provides another powerful check because it traces how light follows spacetime geometry near mass.<\/p>\n Many questions left unanswered<\/p>\n Any alternative theory must stay consistent with precision tests in the solar system and with measurements from binary pulsars<\/a>.<\/p>\n It should also fit what we know about the early universe, including a very rapid expansion phase and its later transition to standard behavior. <\/p>\n Stability and the behavior of small disturbances matter as well; the evolution of ripples influences structure, lensing, and tiny directional differences.<\/p>\n These questions set clear targets for theory and observation. They determine whether the geometry\u2011driven mechanism matches the sky as well as or better than the current model.<\/p>\n Universe, expansion rate, and next steps<\/p>\n This work shows two levers in cosmology: the inventory of what fills the universe and the rules that measure it. <\/p>\n The usual path explains acceleration by adding a constant energy density. This study keeps the inventory lean and modifies the metric so that direction and motion influence measured intervals.<\/p>\n Within that framework, the Universe\u2019s accelerated expansion appears without the need for mysterious and elusive dark energy.<\/p>\n \u201cThis is an exciting indication that we may be able to explain the accelerated\u00a0expansion of the universe\u00a0without\u00a0dark energy, based on a generalized spacetime geometry<\/a>,\u201d concludes Christian Pfeifer, ZARM physicist and member of the research team.<\/p>\n \u201cThe new geometry opens up completely new possibilities for better understanding the laws of nature in the cosmos.\u201d<\/p>\n If predictions align with supernovae, galaxy clustering, the microwave background, lensing, and structure growth, then geometry alone could account for the observed acceleration. <\/p>\n If not, the comparison will still sharpen our understanding of how measurement rules shape cosmic dynamics. Either way, the idea is testable.<\/p>\n The full study was published in the Journal of Cosmology and Astroparticle Physics<\/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":"Astronomers know the universe is expanding, and that its rate of expansion is continually accelerating. Most explanations rely…\n","protected":false},"author":2,"featured_media":230393,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[49,48,314,66],"class_list":{"0":"post-230392","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-ca","9":"tag-canada","10":"tag-physics","11":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/230392","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=230392"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/230392\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/230393"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=230392"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=230392"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=230392"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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\n<\/a><\/p>\n