Overview
- The H0 Distance Network collaboration, in a paper published Friday in Astronomy & Astrophysics, reports H0 = 73.50 ± 0.81 km/s/Mpc with just over 1% precision.
- The value sits nearly 10% above early‑Universe estimates from the cosmic microwave background under the standard ΛCDM model, a difference the team estimates at about 7 sigma.
- The group built a Local Distance Network that combines many independent yardsticks, including Cepheid and Mira variables, TRGB stars, Type Ia supernovae, megamasers, surface brightness fluctuations, Tully–Fisher, and the Fundamental Plane.
- Checks that remove any single technique shift the combined result only slightly, which makes a lone‑method error unlikely and raises the prospect of shared biases or new physics beyond the standard model.
- The team is releasing open data and code for outside review and future use, and the analysis draws on NSF NOIRLab facilities such as CTIO in Chile and Kitt Peak in Arizona to anchor decades of measurements.