Supernovae Point to a Changing Dark Energy ⚡ экспресс
In supernova cosmology, a core assumption is that the standardization of luminosity is unaffected by the age of the progenitor star. However, extensive direct measurements of host galaxy ages uncover a significant (5.5σ) correlation between the standardized supernova magnitude and age. This is expected to introduce a serious redshift-dependent systematic error, largely unmitigated by the standard mass-step correction, since galaxy age and mass evolve differently with redshift. After correcting for this age-dependent systematic as a function of z, the supernova data align better with the w0waCDM model recently proposed by the DESI baryon acoustic oscillation project, based on a joint analysis of BAO and CMB data alone. The result is supported by a no-evolution test using only supernovae from young galaxies with the same age across all redshifts.
Astronomers use Type Ia supernovae as candles. Their brightness was thought to be unchanging. The discovery of the Universe’s acceleration using them brought a Nobel Prize to Riess, Perlmutter, and Schmidt. But measurements of the parent stars’ ages revealed: the older, the dimmer the explosion (5.5 sigma). The farther we look, the brighter supernovae appear — this distorts the picture of the Universe’s expansion. It’s like old candles giving off less light, and we misjudge distances.
Adding to the analysis the ‘echoes’ of the early Universe (baryon acoustic oscillations) and the cosmic microwave background, the contradiction with a constant dark energy intensifies to a staggering 9 sigma. The most unexpected outcome: the Universe’s acceleration may have already stopped.
🎯 Type Ia supernovae are born when a white dwarf pulls matter from a companion star and, reaching a critical mass, explodes. Despite the ‘Ia’ label, they have nothing to do with stellar classes — it’s a historical classification based on spectra.