--- title: "Dark Energy Might Have Changed Over Time: New Model Challenges Foundations of Cosmology" description: "Researchers at Istanbul Technical University have proposed a model in which dark energy changed properties over time. The hypothesis, based on DESI data, could overhaul key foundations of cosmology." date: 2026-10-19T05:15:50.690Z lang: en url: https://xab.info/en/posts/dark-energy-changed-over-time-new-model tags: [dark-energy, cosmology, desi, teleparallel-gravity, universe-expansion, hubble-tension] author: "Alexander Buran" publisher: "XAB.info" --- # Dark Energy Might Have Changed Over Time: New Model Challenges Foundations of Cosmology ![Observatory with star trails in the night sky](https://xab.info/media/2026/10/19/temnaya-energiya-menyaetsa-so-vremenem-novaya-model-kosmologii/temnaya-energiya-menyaetsa-so-vremenem-novaya-model-kosmologii-1.webp) ## Key Points - A team from Istanbul Technical University led by Özgür Akarsu proposed a dark energy evolution model based on teleparallel gravity. - According to calculations, dark energy density was negative in the early Universe and crossed the zero mark to become positive about 9.5 billion years ago. - The model aligns with DESI data and may help resolve the "Hubble tension" problem. - Further testing will be conducted on a dataset of over 47 million DESI objects. One of the central mysteries of modern cosmology is the nature of dark energy, which, according to generally accepted views, is responsible for the accelerated expansion of the Universe. However, new data, in particular results from observations by the DESI spectrograph, lead scientists to think that this component may not have been constant: its properties may have evolved along with the development of the cosmos. Based on these observations, an international team of researchers from Istanbul Technical University led by Professor Özgür Akarsu has proposed a theoretical explanation for this evolution. The work has been published on the arXiv preprint server, as reported by RBC-Ukraine. ### What alarmed cosmologists in the DESI data The Dark Energy Spectroscopic Instrument (DESI) is mapping millions of galaxies in 3D and capturing subtle signs that dark energy is not a strictly constant value as assumed in the standard model. It is these deviations from the "frozen" constant that became the starting point for the new work: the researchers tried to find a theoretical framework in which the change in dark energy density arises not as an artificial assumption, but as a natural consequence of the equations. ### Teleparallel gravity instead of space curvature To explain the observations, the team turned to an alternative theory known as teleparallel gravity. Unlike Einstein's general theory of relativity, where gravity is described through the curvature of spacetime, this theory represents gravity through the rotation, or "torsion," of space. Previously, one of the mathematical variants of this theory was dismissed because it implied a negative dark energy density. The researchers consciously removed this restriction and calculated a scenario in which the corresponding parameter could vary over time. ### How dark energy density supposedly changed according to calculations The calculations showed that in the first billion years after the Big Bang, dark energy possessed a negative density. Approximately 9.5 billion years ago, this indicator crossed the zero mark and has been positive ever since. The authors emphasize that such a transition arises naturally from the mathematical structure of the equations themselves, without the need to introduce additional artificial variables, making the model attractive from the standpoint of theoretical economy. ### "Hubble tension" and testing on 47 million objects In addition to describing the evolution of dark energy, the proposed approach, according to the researchers, helps resolve the so-called "Hubble tension" problem — the discrepancy between theoretical calculations and actual measurements of the Universe's expansion rate. Now scientists are preparing to test the model on the full DESI dataset, covering more than 47 million cosmic objects. If the hypothesis is confirmed, it will radically change humanity's understanding of fundamental laws of physics and how the Universe developed from the early epoch to the present day. ## Fact-Check & Sources - [Загадка расширения Вселенной: ученые обнаружили доказательства эволюции темной энергии](https://www.rbc.ua/ukr/news/zagadka-rozshirennya-vsesvitu-vcheni-znayshli-1791888257.html) - Primary source: description of work by Istanbul Technical University (Özgür Akarsu), teleparallel gravity, dark energy density transition through zero ~9.5 billion years ago, connection to DESI and "Hubble tension", testing plan on 47 million objects. All facts of the article are taken from this source. - [Загадка красных точек: ученые нашли перекормленные черные дыры](https://www.5-tv.ru/news/5089208/zagadka-krasnyh-tocek-ucenye-nasli-perekormlennye-cernye-dyry-aii/) - Подтверждено по источнику 5-tv.ru ## FAQ ### What is dark energy and why is it important? Dark energy is a hypothetical component of the Universe which, according to modern concepts, is responsible for the accelerated expansion of the cosmos. Its properties determine the long-term fate of the Universe. ### What did Istanbul Technical University researchers propose? They proposed explaining the possible evolution of dark energy using teleparallel gravity — an alternative theory where gravity is described through the "torsion" of space rather than its curvature. ### How did dark energy density change according to their calculations? In the early Universe it was negative, and approximately 9.5 billion years ago it crossed zero and became positive. This transition arises from the equation structure itself without extra variables. ### What problem does the new model help solve? According to the authors, the model helps solve the "Hubble tension" problem — the discrepancy between theoretical calculations and real measurements of the expansion rate of the Universe. ### Is the hypothesis finally confirmed? No. This is a theoretical model published on the arXiv preprint server. Scientists are preparing to test it against the full dataset of DESI covering over 47 million cosmic objects.