- Scientists have long believed the universe's expansion is accelerating, a Nobel-winning discovery
- New research suggests the universe's expansion may be slowing down instead of speeding up
- The study indicates dark energy might be weakening over time and changing rapidly
For decades, scientists have believed that the universe is expanding at an ever-accelerating pace, a discovery that earned a Nobel Prize and reshaped modern cosmology. But now, a new study has cast serious doubt on that long-held idea, suggesting instead that the universe's expansion may actually be slowing down, reported the Guardian.
If proven true, this finding could completely change our understanding of the cosmos and its ultimate fate. Rather than expanding forever, the universe could one day stop growing and begin to collapse in a "big crunch," a reverse version of the big bang.
The researchers behind this study also believe that dark energy, the mysterious force thought to drive cosmic acceleration, may be weakening over time.
Professor Young-Wook Lee of Yonsei University in South Korea, who led the research, explained that their observations show the universe has already entered a phase of slower expansion.
He said their results suggest dark energy changes more rapidly over time than previously believed.
According to him, if these findings are confirmed, it would represent a major shift in cosmology since dark energy was first discovered 27 years ago.
This claim is expected to be met with considerable scepticism among scientists Nevertheless, similar findings by the prominent research group Desi Consortium earlier this year have sparked intense debate among astronomers about the true nature of dark energy and the future of the universe.
The latest study calls into question the reliability of earlier measurements of distant supernovae (exploding stars), the very data that led to the discovery of dark energy and the 2011 Nobel Prize.
Professor Li explained that nearly three decades after the discovery of dark energy, astronomers were still relying on an assumption that has now proven to be wrong. He compared it to the first button of a shirt being buttoned incorrectly, causing the rest to fail.
Before the 1990s, it was believed that gravity acted as a "cosmic brake," gradually slowing the expansion of the universe. But this view changed when astronomers began studying Type 1a supernovae. Because the light emitted from these supernovae was assumed to be similar, they were used as "standard candles," and their brightness was used to measure distances in the universe. Observations revealed that distant supernovae appeared dimmer than expected, leading scientists to conclude that the universe's expansion is accelerating, not slowing.
However, new research offers a different explanation. Professor Li's team, by studying 300 host galaxies and estimating their ages using a new method, found that supernovae born from stars in the early universe may be slightly less luminous.
Even after correcting for this discrepancy, the data still shows that the universe is expanding, albeit at a slower rate. The research also suggests that dark energy is weakening, and if it becomes negative, the universe could eventually reach a "Big Crunch."
Professor Carlos Frenk of Durham University, who wasn't involved in the study, called the findings noteworthy. He called them interesting and challenging, adding that even if these conclusions prove wrong, they cannot be ignored.
