Overview
- Researchers at the University of Illinois and the University of Chicago detail the method in a paper published in Physical Review Letters.
- The approach infers cosmic expansion by analyzing the unresolved gravitational-wave background from countless black hole mergers.
- Applied to present LVK data, the absence of a detected background rules out very low H0 scenarios favored by slower-expansion models.
- Combining this background constraint with individual standard-siren events shifts the inferred H0 toward the region of the known tension.
- The authors estimate the background will likely be detected within about six years as detector sensitivity improves, with constraints tightening even before a direct detection.