Edwin Hubble

July 2026

Who he was

Edwin Hubble (1889–1953) was an American astronomer. His 1929 observation that distant galaxies are receding from us at speeds proportional to their distance — now called Hubble’s law — provided the first direct observational evidence that the universe is expanding, confirming what Friedmann had already derived mathematically seven years earlier.

What he’s known for on this site

Hubble expansion is cited throughout this site as one of the three pillars (alongside the CMB and Big Bang nucleosynthesis) of the proven expansion/thermal-history framework in Standard Cosmology. The site also flags the real, unresolved “Hubble tension” — a genuine ~9% discrepancy between two independent measurement methods for the expansion rate — in Generally Accepted But Unproven.

Catalog status: Proven Systems

The expansion of the universe itself is not in question — Hubble’s basic observation has been confirmed and refined continuously for nearly a century. The precise rate of expansion (the Hubble tension) is the genuinely open part.

Mentioned on this site

• Proven Systems — Hubble expansion listed among the confirmed cosmological framework
• Generally Accepted But Unproven — the Hubble tension
• Friedmann Equation

Where this touches PBT

PBT’s own cosmological claims (Paper 9) are checked against the same real expanding-universe framework Hubble’s observations established — PBT doesn’t dispute the expansion itself, only proposes a different mechanism for the residual energy density driving it.