Astrophysicists Reject Claims Universe Expansion Is Slowing
This digest was compiled by AI from multiple sources — links to the originals are below.
An international team of astrophysicists says the universe is still expanding at an accelerating rate, rejecting a 2025 study that claimed cosmic expansion may have begun to slow. The new analysis, published in Monthly Notices of the Royal Astronomical Society, argues the earlier work contained a key error in estimating the ages of exploding stars. The team includes two Nobel Laureates and scientists from institutions worldwide.
Key Facts
- The new paper was published in Monthly Notices of the Royal Astronomical Society.
- Lead author Dr. Phil Wiseman is from the University of Southampton.
- The team includes Professor Adam Riess and Professor Brian Schmidt, who shared the 2011 Nobel Prize in Physics with Professor Saul Perlmutter.
- The South Korean study that claimed decelerating expansion was published last year.
Rejection of Slowdown Claim
The study directly responds to research from a South Korean team that claimed the universe may have entered a period of decelerating expansion. That earlier work suggested dark energy, which acts somewhat like anti-gravity, could be weakening with time. Lead author Dr. Phil Wiseman, from the University of Southampton, said the latest analysis supports the measurements that astronomers have relied on for years. The researchers argue that the standard interpretation remains intact: a mysterious force known as dark energy is continuing to drive the universe's accelerating expansion.
Supernova Evidence
The international research group included Professor Adam Riess and Professor Brian Schmidt, who shared the 2011 Nobel Prize in Physics with Professor Saul Perlmutter. Their Nobel-winning work relied on observations of Type Ia supernovae, extremely bright explosions produced by white dwarf stars. By studying these events at different distances, the researchers found that more distant objects appeared to be receding faster. That evidence led to the conclusion that the expansion of the universe is accelerating.
Problems in Earlier Analysis
The University of Southampton-led team says it found a key problem in the way the earlier study estimated the ages of the exploding stars. The South Korean study argued that Type Ia supernovae did not all reach the same peak brightness as the universe aged. If that were true, astronomers could have been misreading the supernova data and incorrectly concluding that cosmic expansion was speeding up when it was actually slowing. Dr. Wiseman said the previous and well-accepted measurements were, in fact, fine and our current understanding of the fate of the universe remains robust.
1 source
Astrophysicists Reject Claims Universe Expansion Is Slowing
