Spiral nebulae are external galaxies
Naturaleza galáctica de las nebulosas espirales
- Date
- 1924 · confidence high
- Place
- Mount Wilson Observatory, California, United States
- Credited to
- Edwin Hubble
- People
- 👤 Edwin Hubble1889–1953
- Field
- Cosmos & Earth
What was discovered
With the 2.5 m Hooker telescope, Hubble found Cepheids in Andromeda and calculated that it lay far outside the Milky Way. The universe filled with galaxies.
Announced on 1 January 1925 at the AAS meeting; it settled the Great Debate.
What it led to
- Extragalactic astronomy
- Morphological classification of galaxies
- Hubble's law