DESI data hints dark energy is weakening, challenging cosmology's standard model

Dynamical dark energy and the week that broke cosmology

New results from the Dark Energy Spectroscopic Instrument (DESI) suggest dark energy may not be constant but weakening over time, a finding that challenges the standard model of cosmology. The analysis, based on DESI's second data release, did not reach the 5-sigma threshold for a discovery but has sent shockwaves through the cosmology community. The results, presented in March 2025, could help resolve tensions like the Hubble tension and the neutrino mass problem.