🔬 Discovery

Expansion of the universe (Hubble-Lemaître law)

Expansión del universo y ley de Hubble-Lemaître

Date: 1927-1929 · confidence high
Place: Mount Wilson Observatory, California, United States
Credited to: Edwin Hubble; Milton Humason (theory: Georges Lemaître, 1927)
People: 👤 Edwin Hubble1889–1953 👤 Milton Humason1891–1972
Field: Cosmos & Earth

⚠️ Disputed: the sources disagree.

What was discovered

The recession velocity of galaxies is proportional to their distance: the universe is expanding. Lemaître had derived this from relativity and proposed an origin in a 'primeval atom'.

Vesto Slipher measured redshifts from 1912 at Lowell; the IAU renamed the law in 2018 to recognise Lemaître.

🌍 View on the globe

What it led to

Big Bang cosmology
Finite age of the universe
Hubble constant and the Hubble tension

🕸️ View in the graph

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Made possible

📄 Original publication

A relation between distance and radial velocity among extra-galactic nebulaeEdwin Hubble · Proceedings of the National Academy of Sciences · 1929