Cosmological parameter · σ8
Amplitude of Fluctuations (σ8)
A measure of how clumpy the universe is — the amplitude of matter-density fluctuations averaged over spheres of 8 megaparsecs. It links the smooth early universe to today's web of galaxies, and a mild disagreement between its early-universe and weak-lensing determinations — usually quantified through the related combination S8 — is known as the S8 tension.
Methods, objects & facilities
Knowledge connections
- Associated withStructure Formation
- Associated withLarge-Scale Structure
- Associated withDark Matter
Sources
The primary and reference sources this topic draws on.
- Planck CollaborationESA Planck mission / Planck Collaboration
Cosmic microwave background maps and the cosmological parameters of the ΛCDM model.