Supernova (SN) cosmology is based on the assumption that the luminosity of type Ia SNe, after the luminosity standardization process, remains invariant with progenitor age. However, our comprehensive age measurements of SN host galaxies reveal a significant (5.5σ) correlation between standardized SN luminosity and progenitor age, which is expected to introduce a serious systematic bias with redshift in SN cosmology. After correcting for this age bias with redshift, the SN dataset aligns more closely with the recent DESI BAO result, bringing the updated ’standard candle’ (SNe) into concordance with the ’standard ruler’ (BAO). When the three cosmological probes (SNe, BAO, CMB) are combined, we find a strong (∼9σ) discordance with the ΛCDM model, suggesting a time-varying dark energy equation of state in a currently non-accelerating universe.
Chung et al. (2026) studied this question.