Sarkar Challenges 5-6 Billion-Year Cosmic Acceleration, Questions Dark Energy
Updated
Updated · Yahoo! Voices · Aug 4
Sarkar Challenges 5-6 Billion-Year Cosmic Acceleration, Questions Dark Energy
2 articles · Updated · Yahoo! Voices · Aug 4
Summary
Pantheon+ supernova data reanalyzed by Subir Sarkar and colleagues suggest the universe’s apparent acceleration may be an observational artifact rather than evidence for dark energy.
Type Ia supernovae from younger progenitor stars appear systematically fainter after age correction, and because more distant supernovae tend to be younger, they can look farther away and falsely imply faster expansion.
The team says the signal is anisotropic: the strongest apparent acceleration aligns with our local cosmic motion and weakens with distance, fitting a local bulk-flow effect better than an isotropic cosmological constant.
If that holds up, the universe would still be expanding but not speeding up uniformly—and may instead be slowing—undercutting a core assumption of the standard ΛCDM model.
The result also bears on the Hubble tension, because correcting for progenitor age leaves the local dipole unchanged within uncertainties and adds to broader doubts about perfect large-scale isotropy.