Measurements of the cosmic microwave background show that the Hubble constant, which relates a galaxy’s escape velocity to its distance, is 67.31 kilometers per second per megaparsec. At the same time, other methods, including those based on measuring distances to standard candles in galaxies, point to a different value of the Hubble constant – between 73.3 and 76.5 kilometers per second per megaparsec. This is too large a discrepancy, called the Hubble tension.
One likely explanation for the stress is an error in determining distances to standard candles. For example, the period of cepheids differs slightly depending on their metallicity and other factors. In the new study, more than a thousand Cepheids were studied to determine their distances with high accuracy. It turned out that the error scenario is eliminated at the statistical level of eight standard deviations (sigmas). In physics, a result at or above the five sigma level is considered fairly reliable.
