Olbers's paradox (dark night sky paradox)
Paradoja de Olbers (paradoja del cielo oscuro)
- Date
- c. 1600 · confidence low
- Place
- London, England, United Kingdom
- Credited to
- Thomas Digges (original formulation); named after Heinrich Wilhelm Olbers (1823)
- Field
- Cosmos & Earth
⚠️ Disputed: the sources disagree.
What was discovered
By extending the Copernican model to an infinite universe with infinite stars, around 1600 Digges raised the contradiction that the night sky should be fully lit. Kepler framed it as an explicit problem in 1610, Halley and Cheseaux gave it mature form in the 18th century, and it ended up being called 'Olbers's paradox' after the version he published in 1823, though he was neither the first nor the most rigorous to pose it.
Authorship is diffuse: Digges hinted at it around 1600, Kepler posed it in 1610, Halley and Cheseaux developed it in the 18th century, and the name stuck from Olbers's 1823 version despite not being the most valuable contribution.
What it led to
- Cosmological debate over an infinite, static universe
- Modern explanation via cosmic expansion and redshift (Big Bang)
Built on
- Copernican heliocentric model