Astronomer · 1889 CE – 1953 CE

Edwin Hubble

Biography

Edwin Hubble used the 100-inch telescope at Mount Wilson to settle the greatest question of his day: the spiral 'nebulae' are separate galaxies, vast and distant. In 1929 he showed that the more distant a galaxy, the faster it recedes — the expansion of the universe — laying the observational foundation of modern cosmology.

Scientific contributions

Proved that galaxies exist far beyond the Milky Way
Discovered the expansion of the universe (Hubble's law)
Devised the morphological classification of galaxies

Major discoveries

The Expansion of the Universe1929 CE

Observatories, instruments & objects

Worked at

Mount Wilson Observatory

Observed

Andromeda Galaxy

Knowledge connections

Sources & references

The primary and reference sources this topic draws on.

NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
BritannicaEncyclopaedia Britannica
General reference for the history of astronomy, biographies, and cultural context.

Quick facts

Lifespan: 1889 CE – 1953 CE
Nationality: American
Era: Modern Astronomy
Fields: Extragalactic astronomy, Cosmology
Institutions: Mount Wilson Observatory
Discoveries: 1

Quality & authority

Substantial

Reviewed

Description: Complete
Source coverage: Partial
Relationship coverage: Complete
Review coverage: Complete
Citation coverage: Complete
Image coverage: Not applicable

Curated from authoritative reference sources. See source quality.

Provenance & sources

review 2026.1

Asteria Scientific Review Process · verification: sourced · accurate

Historical evidenceconfirmed
Edwin Hubble demonstrated in the 1920s that galaxies lie far beyond the Milky Way and that their recession velocities increase with distance, foundational evidence for an expanding universe.
Source: Encyclopaedia Britannica

Reviewed by the internal Asteria Scientific Review Process — not an external institutional review. See the evidence framework and authority dashboard.

Scientific citations

Real, source-backed references — primary papers first, then datasets and institutional sources. Formatted through the citation engine; nothing is fabricated.

Peer-reviewed paperA relation between distance and radial velocity among extra-galactic nebulae

Edwin Hubble · PNAS 15 (3), 168–173 · 1929

Proceedings of the National Academy of Sciences · doi:10.1073/pnas.15.3.168

Cite (APA / BibTeX)

Edwin Hubble (1929). A relation between distance and radial velocity among extra-galactic nebulae. PNAS 15 (3), 168–173. Proceedings of the National Academy of Sciences. https://doi.org/10.1073/pnas.15.3.168

@misc{cite:hubble-1929,
  title        = {A relation between distance and radial velocity among extra-galactic nebulae},
  author       = {Edwin Hubble},
  organization = {Proceedings of the National Academy of Sciences},
  howpublished = {PNAS 15 (3), 168–173},
  year         = {1929},
  doi          = {10.1073/pnas.15.3.168},
  url          = {https://doi.org/10.1073/pnas.15.3.168},
  note         = {The velocity–distance relation (Hubble's law).}
}

Historical referenceEdwin Hubble — Encyclopaedia Britannica

Encyclopaedia Britannica

Cite (APA / BibTeX)

Encyclopaedia Britannica (n.d.). Edwin Hubble — Encyclopaedia Britannica. Encyclopaedia Britannica. https://www.britannica.com/biography/Edwin-Hubble

@misc{cite:britannica-astronomer-edwin-hubble,
  title        = {Edwin Hubble — Encyclopaedia Britannica},
  organization = {Encyclopaedia Britannica},
  year         = {n.d.},
  url          = {https://www.britannica.com/biography/Edwin-Hubble},
  note         = {Biographical and background reference for Edwin Hubble (secondary source).}
}