After a six-year study of 669 million galaxies, dark energya mysterious phenomenon that causes the accelerated expansion of the universe.
This groundbreaking study paints a complex picture of our understanding of the universe, showing that the two major theories of cosmology are both equally compatible with new observations of the expansion of the universe. However, both theories are still insufficient to explain why there are such clumps of matter in the universe, suggesting there is still work to be done.
“These results from the dark energy survey shed new light on our understanding of the universe and its expansion.” Regina LameikaDeputy Director of the U.S. Department of Energy’s High Energy Physics Office, said: statement. “It shows how a combination of long-term investment in research and multiple types of analysis can provide insight into some of the universe’s greatest mysteries.”
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Dark energy is thought to make up about 70% of the total energy in the universe, but astronomers still know little about its true nature. Scientists proposed this concept to explain observations that suggest the universe is expanding at an ever-accelerating rate. DES is one of several collaborations developed to study the phenomenon in more detail.
In a new paper posted to a preprint server arXiv On January 21, DES scientists investigated the expansion of the universe using four different markers. Baryon acoustic oscillations, or fluctuations in the density of ordinary matter throughout the universe. Type Ia supernovae are stellar explosions that help scientists measure the distances of objects in the universe. Galaxy cluster. Weak gravitational lensing occurs when a galaxy cluster warps space-time and distorts the apparent shape of objects behind it. A series of 18 supporting papers delves into the findings.
Overall, the data and analysis are consistent with previous research on dark energy, but the new study places tighter constraints on models of how the universe behaves. The data are broadly consistent with the standard model of cosmology, in which the density of dark energy is constant. The data also agreed with a related model in which the dark energy density changes over time, but it was a less good fit than the standard model.
“Based on all the data and using all four probes that DES had planned, it is an incredible feeling to see results like this,” said the study co-authors. Zhang Yuanyuansaid astronomers at the National Science Foundation’s NOIRLab, which manages the telescope, in a statement. “This was something we were only brave enough to dream about when DES started collecting data, but now that dream has become a reality.”
Although the fit between the data and the standard model is relatively good, several questions remain. The patterns of galaxy clustering still do not match exactly what the Standard Model predicts, but the differences are not large enough to conclude that the Standard Model is wrong, the researchers added.
Still, DES researchers are using this and other dark energy models to Vera C. Rubin Observatory In Chile, to further our understanding of mysterious phenomena.
“Rubin’s unprecedented exploration of the southern sky will enable new experiments in gravity and shed light on dark energy.” chris davissaid NOIRLab’s NSF program director in a statement.
DES Collaboration, TMC Abbott et al. (January 21, 2026). Dark Energy Survey Year 6 Results: Cosmological Constraints Due to Galaxy Clustering and Weak Lensing. arXiv.org. https://arxiv.org/abs/2601.14559