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.
The seminar announcement called it 'the week that broke cosmology.'
- MarkusQ
> A recent analysis by the Dark Energy Survey Supernova Program also finds a preference for evolving dark energy, in the same direction as DESI DR2, but with a slightly lower statistical significance (bringing the combined significance down from 4.2 sigma to only 3.2).
Is this right? It would seem that adding another finding "in the same direction" should always increase the statistical significance, even if only slightly if the new evidence is week.
Under what circumstances could additional evidence for X reduce the estimated likelihood of X?
- ck2
to be fair, cosmology has been broken every several months lately (Hubble Tension, etc.)
I mean that's how science works, discover something new, rewrite knowledge
not like religion where you make stuff up before you know anything about anything and then force everything new to adapt to the legacy of decisions thousands of years prior