theory.toys – H₀ Tension Explorer

Systematic Adjustments

Cepheid Systematic (km/s/Mpc): 0.0

CMB Systematic (km/s/Mpc): 0.0

Scenario Explorer

Resolution Scenario: 🔑 Unlock

Statistical Measures

The Hubble Tension

Different measurement methods give inconsistent values of the Hubble constant H₀. Early universe (CMB) measurements yield ~67 km/s/Mpc, while late universe (distance ladder) measurements yield ~73 km/s/Mpc—a discrepancy of ~5σ.

Measurement Methods:

Planck CMB: Sound horizon at recombination
SH0ES Cepheids: Distance ladder calibration
TRGB: Tip of the Red Giant Branch
Megamasers: Geometric distances
Gravitational Waves: Standard sirens (low precision)
BAO + BBN: Baryon acoustic oscillations

This tension may indicate new physics, systematic errors, or modifications to ΛCDM cosmology.