The recent paper on supernova cosmology reveals a significant correlation (5.5 σ) between standardized Type Ia supernova (SN) magnitude and progenitor age, challenging the assumption of luminosity standardization invariance. This correlation introduces a systematic bias in supernova distance measurements that is not adequately corrected by the mass-step correction. After adjusting for progenitor age as a function of redshift, the supernova data aligns more closely with the cold dark matter (CDM) model proposed by the Dark Energy Spectroscopic Instrument (DESI) project. The findings suggest a decelerating universe, contradicting previous conclusions about accelerated expansion.
PREREQUISITESAstronomers, cosmologists, and astrophysicists interested in the evolution of the universe, the role of supernovae in cosmological measurements, and the ongoing debate regarding dark energy and the expansion of the universe.
Ah, thank you! That was basically my guess but I didn't want to assume.PeterDonis said:That shouldn't be possible with a cosmological constant, because the energy density of matter and radiation can only decrease with expansion, so once the universe has expanded to the point where the cosmological constant dominates, it should keep dominating (i.e., expansion should keep accelerating) forever after that.
Yeah that's what I was getting at. Hopefully we'll get some interesting responses/rebuttals in the coming months.PeterDonis said:In other words, IMO that pattern of accelerated expansion starting 7 bya and then stopping 2 bya is a reason to doubt that the findings of this paper are actually valid.