The Hubble constant (H₀) tells us how fast the universe is expanding. Measure it one way — using the early universe (cosmic microwave background) — and you get one number. Measure it another way — using the nearby universe (Type Ia supernovae, Cepheid variables) — and you get a different number.
These two numbers don't agree. And the disagreement has been growing for over a decade.
The units are km/s/Mpc (kilometers per second per megaparsec). The early universe says the expansion rate is about 67. The local universe says it's about 73. That's an 8% gap. In particle physics, 5σ is the threshold for claiming a discovery — the point at which the probability of the result being a statistical fluke drops below 1 in 3.5 million.
Why It Matters
This isn't a minor calibration error. The Hubble constant is calculated from the standard model of cosmology (ΛCDM — Lambda Cold Dark Matter). If the model were correct, both measurements would agree. They don't. Which means one of two things:
Either there's an unknown systematic error in one of the measurements (and teams on both sides have spent years eliminating this possibility), or the standard model is missing something.
What 5σ Means
In physics, confidence levels are measured in sigma (σ). The higher the sigma, the less likely the result is a fluke.
3σ = evidence (1 in 740 chance of being random)
4σ = strong evidence (1 in 31,574)
5σ = discovery threshold (1 in 3,488,555)
The Higgs boson was confirmed at 5σ. The Hubble tension is now at 5σ. By physics' own standard, this is a real discrepancy.
The Theophysics Reading
The standard model assumes a cosmological constant (Λ) — a fixed value that governs the expansion rate uniformly across all time. The Hubble tension suggests this assumption is wrong. The expansion rate appears to change over time in a way the model doesn't predict.
In the Theophysics framework, this is expected. If the Master Equation (χ) describes a universe where coherence is not static but dynamically sustained by an external source, then the expansion rate wouldn't be a fixed constant — it would be modulated by the coherence field. The Hubble tension may be measuring the signature of χ(t) — coherence that varies in time.
The prediction: If Theophysics is correct, the Hubble tension will not be resolved by finding a measurement error. It will be resolved by discovering that the expansion rate is time-dependent in a way that correlates with coherence dynamics — not random variation, but structured modulation from outside the system.
This is a falsifiable prediction. If the tension is resolved by a mundane calibration fix, the Theophysics reading loses support. If it requires new physics involving time-dependent cosmological parameters, the framework gains it.
What the Mainstream Says
The physics community is genuinely split. The Nobel Prize was awarded in 2011 for discovering the accelerating expansion (which led to the tension). Multiple independent teams have confirmed the discrepancy using different methods. Proposed solutions range from "early dark energy" to modified gravity to decaying dark matter — all of which amount to admitting something fundamental is missing from the model.
The honest position is: we don't know why the universe's expansion rate disagrees with itself. The standard model, which has been spectacularly successful for decades, has a 5σ crack in its foundation. What fills that crack will reshape cosmology.