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New BAO Analysis Strengthens Local Void Solution to Hubble Tension

This analysis undermines the ΛCDM assumption of cosmic uniformity, prompting independent validation through cosmic chronometers and other expansion probes.

© Moritz Haslbauer and Zarija Lukic
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Overview

  • Analysis of 20 years of baryon acoustic oscillation data presented at NAM 2025 finds a local void model is roughly 100 million times more likely than a homogeneous ΛCDM fit.
  • Galaxy surveys indicate a matter density about 20% below the cosmic average within a roughly 1–2 billion–light-year region surrounding the Milky Way.
  • In the void scenario, gravitational flows toward denser exterior regions produce locally accelerated expansion that could account for the higher Hubble constant measured nearby.
  • If validated, the local void would shift the interpretation of the Hubble tension from a failure of early-universe physics to a feature of our immediate cosmic environment.
  • Researchers now plan to test the void model against independent chronometric methods and redshift probes to confirm or refute its role in the cosmic expansion history.