Astronomers Achieve 1% Precise Hubble Constant of 73.50 km/s/Mpc

An international team of astronomers has produced the most precise direct measurement to date of the universe's expansion rate, reporting a Hubble constant value of 73.50 kilometers per second per megaparsec with an uncertainty of just 0.81, achieving better than 1 percent precision. The findings, published on April 10, 2026, in the journal Astronomy & Astrophysics, stem from the H0 Distance Network Collaboration and intensify a longstanding puzzle in cosmology known as the Hubble tension.

The Hubble constant quantifies how quickly the universe is expanding, with more distant galaxies receding faster than those nearby. For every megaparsec of distance, roughly 3.26 million light-years, the recession speed increases by about 73.5 kilometers per second, according to the new analysis. This local measurement aligns with previous observations of nearby stars and galaxies but conflicts with predictions from the early universe, which suggest a slower rate of 67 to 68 kilometers per second per megaparsec.

To reach this level of accuracy, the collaboration developed a "Local Distance Network," a unified framework that integrates decades of independent observations from multiple...