Around 270 BC the Greek astronomer Aristarchus of Samos proposed that the Sun and the stars are fixed and the Earth revolves around the Sun in a circle, while spinning daily on its axis. His book is lost, and we know of the theory through Archimedes in The Sand Reckoner. Aristarchus had also worked out, using the geometry of the half Moon, that the Sun is some 20 times farther than the Moon (it is 400 times), and much larger than the Earth, which probably made him think that the small should go round the big. Few accepted this, and the Earth-centred system of Ptolemy prevailed until Copernicus.
Before and after
- from 280 BCE to 275 BCEPyrrhic War
- from 279 BCE to 1480Construction of Lighthouse of Alexandria
- 276 BCEBirth of Eratosthenes
- from 274 BCE to 168 BCESyrian Wars
- c. 270s BCEAristarchus of Samos proposes that the Earth orbits the Sun
- from 267 BCE to 261 BCEChremonidean War
- from 264 BCE to 146 BCEPunic Wars
- from 264 BCE to 241 BCEFirst Punic War
- 261 BCEBattle of Agrigentum
More in Science & technology
- 370 BCEDeath of Hippocrates
- 190 BCEBirth of Hipparchus
- 141 BCEPaper
- 105 CECai Lun reports the invention of paper
- 170 CEDeath of Ptolemy
- 476 CEBirth of Aryabhata
The era
This moment belongs to the Ancient civilizations (3,200 BCE to 500 CE), writing, cities and empires. You can also browse everything in the 3rd century BCE.