When you buy through links on our articles, Future and its syndication partners may earn a commission.Two “fans” representing DESI observations above and below the plane of the Milky Way. | Credit: DESI Collaboration/DOE/KPNO/NOIRLab/NSF/AURA/R. Proctor/ Robert Lea (created with Canva)As if dark energy weren’t already mysterious and baffling enough, new research suggests that this unknown force may not be driving galaxies apart at an accelerating rate anymore.This remarkable result comes from research that suggests that the expansion of the universe has already begun to slow, contrary to the currently favored belief that dark energy is still accelerating the expansion of the cosmos. The discovery also follows results from the Dark Energy Spectroscopic Instrument (DESI) that last year indicated that dark energy is weakening.AdvertisementAdvertisementAdvertisementAdvertisementThis research could not only revolutionize our understanding of the universe as it is today, but also offer clues about how our cosmos will end. If dark energy has already lost the battle against gravity, the next step after slowing cosmic expansion could be the contraction of space, and that could suggest the universe will end in a “Big Crunch” scenario akin to the Big Bang playing in reverse.The researchers behind this discovery are already hailing it as a possible paradigm shift in how we think about the very nature of the universe. “Our study shows that the universe has already entered a phase of decelerated expansion at the present epoch and that dark energy evolves with time much more rapidly than previously thought,” Young-Wook Lee, team leader and researcher at Yonsei University in South Korea, said in a statement. “If these results are confirmed, it would mark a major paradigm shift in cosmology since the discovery of dark energy 27 years ago.”Dark energy evolvesThe existence of dark energy was first suggested in 1998 when two separate teams of astronomers observed distant Type Ia supernovas, also referred to as “standard candles” due to the fact that their uniform light output can be used to measure cosmic distances. This revealed that the further away a galaxy was, the faster it was receding away. This indicated to the two teams, who received the 2011 Nobel Prize in Physics for the discovery, that the speed at which the universe expands is increasing. Dark energy was introduced as a placeholder force to explain this accelerating expansion.Over the following three decades, while scientists have been unable to conclusively determine what dark energy is, they have found that this force is dominant, accounting for approximately 68% of the universe’s total energy-matter budget. Researchers also discovered that dark energy had not always been dominant, appearing to begin its rule and start speeding up the expansion of the universe around 5 billion years ago, or roughly 9 billion years after the Big Bang.AdvertisementAdvertisementAdvertisementAdvertisementThe first indication that dark energy may not be as dominant as previously thought emerged courtesy of the first results from DESI in Spring 2024. This new chink in the armor of dark energy resu …
