Supernovae Point to a Changing Dark Energy ⚡ экспресс
Type Ia supernovae are cosmology’s ‘standard candles.’ But a study found their calibrated brightness drops with the age of the parent star (5.5σ correlation). The galaxy mass correction doesn’t fix this, introducing a redshift-dependent systematic shift. After accounting for the age trend, supernova data better fit the w0waCDM model with evolving dark energy, earlier proposed by DESI. Combining with baryon acoustic oscillations and the cosmic microwave background pushes the tension with ΛCDM to >9σ, hinting the universe may not be accelerating now.
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.