Astronomers have confirmed that the universe is still expanding at an accelerating rate. This finding overturns a recent challenge to dark energy, the mysterious force thought to be behind this expansion.
A new study reinforces one of modern science's most important discoveries. It shows that the universe is behaving as current models predict.
Reaffirming Dark Energy
A controversial claim in late 2025 suggested that dark energy might be weakening. This would have questioned decades of research. However, researchers from the University of Southampton found that the original measurements are reliable.
We're a new kind of news feed.
Regular news is designed to drain you. We're a non-profit built to restore you. Every story we publish is scored for impact, progress, and hope.
Start Your News DetoxThe team's findings were published in the Monthly Notices of the Royal Astronomical Society. Nobel Prize winners Professor Adam Riess and Professor Brian Schmidt were part of this international team.
Lead author Dr. Phil Wiseman explained that the controversy came from a misunderstanding in data analysis. He noted that the previous measurements were correct.
"Our current understanding of the universe's fate remains robust," Wiseman said. "We can now focus on understanding what dark energy is, rather than questioning if it exists."
Professors Riess and Schmidt, along with Saul Perlmutter, first discovered the universe's accelerating expansion. They won the Nobel Prize in Physics in 2011 for this work.
If the 2025 challenge had been correct, it would have undermined nearly 30 years of cosmological research. Professor Riess emphasized the need for careful testing of extraordinary claims.
He said, "When we calibrate these supernovae, accounting for different host environments and populations, the evidence for cosmic acceleration remains remarkably consistent."
Supernova Measurements
The Southampton team reexamined observations of Type Ia supernovae. These are bright explosions of white dwarf stars used to measure vast distances in space.
The 2025 study claimed that these supernovae had different peak brightness levels as the universe aged. This led to the idea that cosmic expansion might be slowing, not accelerating.
However, the new study found issues with that analysis. The earlier work incorrectly assumed that a galaxy's age was the same as the age of the star that became a supernova. This led to inaccurate results.
The researchers also noted that the 2025 paper did not properly account for the mass of the galaxies hosting the supernovae. This correction is standard in modern cosmological studies to improve measurement accuracy.
Lessons for Cosmology
Professor Mark Sullivan highlighted that questioning established ideas is crucial for scientific progress.
He noted, "Although this idea did not turn out correct, it has opened up new ways of thinking about how supernovae explode and how we can measure dark energy more accurately."
Co-author Dr. Brodie Popovic added that the study allowed them to reexamine assumptions in modern cosmology.
He said, "We've recently been really focused on astrophysics of the explosions and how they impact cosmology. This was a good opportunity to go back and go over all of our assumptions – it turns out, yes, we do understand this stuff, and we’re accounting for it in our cosmology measurement."
Deep Dive & References
- Still accelerating: type Ia supernova cosmology is robust to host galaxy age evolution - Monthly Notices of the Royal Astronomical Society, 2026
