5 kilometers per second per megaparsec based on measurements of nearby stars and galaxies. This discrepancy between different measurement methods, called the Hubble tension, has been appearing in numerous studies. According to the researchers, this work effectively rules out explanations that rely on a single overlooked error in local distance measurements.
The authors stated that if the tension is real, as the growing body of evidence suggests, it may point to new physics beyond the standard cosmological model. The discrepancy could stem from unaccounted factors such as dark energy, new particles, or changes to gravity. What specific new physics or cosmological model could explain the Hubble tension remains unknown, as does whether dark energy, new particles, or modified gravity are the actual cause.
How this discrepancy will affect future cosmological theories and measurements is also unclear.