A new study published in Monthly Notices of the Royal Astronomical Society suggests that a slowly spinning universe could help solve one of astronomy’s biggest puzzles, the Hubble tension. Researchers, led by István Szapudi from the University of Hawaiʻi at Mānoa Institute for Astronomy, propose that the universe may rotate, but extremely slowly.
The current understanding is that the universe expands evenly in all directions with no sign of rotation. However, two different methods of measuring the expansion rate of the universe give conflicting results, known as the Hubble tension. One method uses supernovae to measure distances to galaxies, while the other relies on relic radiation from the Big Bang.
Szapudi’s team developed a mathematical model of the universe that includes a small amount of rotation. To their surprise, this tiny change made a significant difference in resolving the paradox without contradicting current astronomical measurements. The model suggests that the universe could rotate once every 500 billion years, which is too slow to detect easily but enough to affect how space expands over time.
The idea does not break any known laws of physics and may also explain why measurements of the universe’s growth do not agree. Further research is needed to turn this theory into a full computer model and spot signs of this slow cosmic spin.
Source: https://phys.org/news/2025-04-slowly-universe-hubble-tension.html