A Twist in Space: The Universe Might Be Slowing Its Expansion

For more than two decades, scientists believed the universe was expanding at an ever-accelerating rate, driven by a mysterious force known as dark energy.

That theory, which won the 2011 Nobel Prize in Physics, may now be facing a serious challenge. Astronomers at South Korea’s Yonsei University have published new findings in the Monthly Notices of the Royal Astronomical Society suggesting that the expansion of the universe is no longer speeding up—and may actually be slowing down.

Their research reexamined the light of type Ia supernovae, long used as cosmic “standard candles” to measure distance, and found that their brightness depends on the age of the stars that created them.

Accounting for this, the data no longer supports an accelerating universe. Instead, it points to a weakening dark energy force that could eventually halt cosmic expansion altogether.

If confirmed, the finding could radically change our understanding of the universe’s future—raising the possibility of a “Big Crunch,” where galaxies collapse back into a single point.