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Global Collaboration Pins Local Hubble Constant at 73.50 ± 0.81 km/s/Mpc With 1% Precision

The cross-checked result challenges simple measurement-error fixes to the Hubble tension.

Overview

  • The H0 Distance Network paper, published April 10 in Astronomy & Astrophysics, reports Ho = 73.50 ± 0.81 km/s/Mpc with just over 1% precision.
  • The team built a Local Distance Network that links many independent yardsticks such as Cepheids, Miras, TRGB stars, Type Ia supernovae, megamasers, surface brightness fluctuations, Tully–Fisher, and the Fundamental Plane.
  • Tests that removed individual methods changed the final value only slightly, showing the measurement does not rely on any single technique.
  • The new value is nearly 10% higher than early‑Universe estimates from the cosmic microwave background under ΛCDM, a gap reported at about 7 standard deviations.
  • The collaboration began at a 2025 ISSI workshop and has released open data and software to enable checks and follow‑ups using inputs that include NOIRLab observations from CTIO and KPNO.