A new analysis of DESI’s first year of data provides a rigorous test of general relativity and how gravity behaves on a cosmic scale. Researchers looked at galaxies and their clustering patterns over time to study the growth of cosmic structure, which also informs theories of modified gravity.
The study found that the way galaxies cluster is consistent with our standard model of gravity and the predictions from Einstein’s theory of general relativity. Gravity has shaped the cosmos by turning small differences in matter into the sprawling galaxy structures we see today.
DESI, an international collaboration of over 900 researchers, used nearly 6 million galaxies and quasars to analyze the data. The study provides a precise test of gravity at large scales, validating our current understanding of the universe.
The findings also place new limits on the mass of neutrinos, with the DESI results indicating that their sum should be less than 0.071 eV/c2. This narrow window for neutrino masses is significant, as previous experiments found a sum of at least 0.059 eV/c2.
DESI’s analysis used a “full-shape” technique to extract more information from the data and measure how galaxies and matter are distributed on different scales throughout space. The study was completed after months of additional work and cross-checks, ensuring the accuracy of the results.
The collaboration plans to present updated measurements of dark energy and the expansion history of the universe in spring 2025. DESI’s expanded results add to the anticipation of these analyses, which will help scientists better understand the nature of dark matter and dark energy.
Source: https://newscenter.lbl.gov/2024/11/19/new-desi-results-weigh-in-on-gravity