Researchers from the Tata Institute of Fundamental Research and the University of Oxford have published a study questioning whether cosmic acceleration is real or an artifact of observational analysis. The research, led by Professor Subir Sarkar, re-examined data from more than 1,700 Type Ia supernovae contained in the Pantheon+ dataset, which has been central to cosmological studies for over 25 years.
The team incorporated a recently proposed correction accounting for the ages of stars that produce Type Ia supernovae. According to their findings, when this age-related adjustment is applied, the observations no longer support uniform cosmic acceleration. Instead, their analysis suggests the universe’s expansion may be decelerating rather than accelerating. Additionally, the researchers investigated whether any apparent acceleration varies directionally, which would contradict standard cosmological models assuming uniform properties across all directions.
The analysis revealed that the apparent acceleration, if present, appears concentrated along the direction of local cosmic motion indicated by the cosmic microwave background hotspot and diminishes with distance. The researchers argue this directional pattern is incompatible with dark energy, since effects from quantum vacuum phenomena should not vary by direction. Professor Sarkar noted that the stellar age correction transforms the isotropic acceleration component into deceleration, ruling out dark energy independently of whether the correction applies.
However, disagreement persists within the research community. A separate paper in the same journal issue, co-authored by Professor Maria Vincenzi, also at Oxford, maintains that available observational evidence continues to support cosmic acceleration and reinforces the standard cosmological framework developed over recent decades.
Future observations from the Rubin Observatory’s Legacy Survey of Space and Time are expected to resolve the debate through measurements of hundreds of thousands of additional supernovae, providing a definitive test of whether cosmic acceleration is occurring and dark energy’s actual role in the universe’s expansion.
Article Attribution | Read More at Article Source
Article summary produced by Claude AI