Thu May 01 00:00:00 UTC 2025: ## New Research Suggests Dark Matter and Dark Energy Key to Universe’s “Clumpiness”

**Pune, India (May 1, 2025)** – A new study utilizing data from the Subaru Telescope’s Hyper-Suprime-Cam has shed light on the “S8 tension” in cosmology, a discrepancy in measurements of the universe’s large-scale structure. The research, published in *Physics*, indicates that the disagreement in estimations of Sigma 8 (S8), a measure of matter clumping, stems from the behavior of dark matter and dark energy.

The standard cosmological model, ΛCDM, suggests that dark matter and dark energy account for approximately 95% of the universe. The study found an S8 value of 0.747, consistent with previous surveys using gravitational lensing. This value, however, differs from higher estimates derived from observations of the cosmic microwave background (CMB).

Professor Surhud S. More, a co-author of the study and astrophysics professor at the Inter-University Centre for Astronomy and Astrophysics in Pune, explained that the discrepancy cannot be attributed to the movement of ordinary matter. The research team probed matter distribution down to small scales, demonstrating that the issue lies within the dark matter and dark energy components.

While reaffirming the validity of the ΛCDM model, the findings don’t resolve the S8 tension. The CMB remains a crucial tool for studying the early universe, but the persistence of the discrepancy suggests the model may require modifications, or that undiscovered systematic errors are affecting the results. Challenges remain, including accurately determining the redshift of faint galaxies in deep surveys.

The upcoming Rubin Legacy Survey of Space and Time (LSST) is expected to provide further insights. This ambitious project, using the largest camera ever built, promises unprecedented data on the universe’s structure, potentially resolving lingering questions regarding the nature of dark matter and dark energy and the evolution of the cosmos. The possibility that dark energy is weakening, potentially leading to a future universe contraction, adds another layer of complexity to this ongoing cosmological investigation.

Read More