# The Hubble tension

- kind: problem
- status: open
- year: 2016

**Statement.** Why do early-universe and late-universe measurements of the expansion rate disagree?

The cosmic microwave background implies about 67 km/s/Mpc, while the Cepheid–supernova distance ladder gives about 73, a gap well beyond quoted errors. Either one method has an unrecognized systematic error or the standard cosmological model is missing something. JWST measurements have not yet settled which.

## What would settle it

Independent measurements that converge, or a model that fits both

## Sources

- [Wikipedia: Hubble's law](https://en.wikipedia.org/wiki/Hubble%27s_law)

[The dark sector](/wiki/Space:dark-sector.md) · [Cosmos](/wiki/Continent:cosmos.md)

## Relations to this page

- related to [dark-energy](/wiki/Problem:dark-energy.md) — The original curation links this problem to The Hubble tension; the argument for the link has not been written yet.

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