c. 3rd century BCE / West Asia & North Africa
Aristarchus imagines a moving Earth
Aristarchus proposed a Sun-centred model, known mainly through other ancient authors because his heliocentric text is lost.
The story
He also used geometry to investigate the sizes and distances of the Sun and Moon. Reports describe a rotating Earth orbiting the Sun, but the proposal cannot be dated precisely. Very distant stars could explain the absence of visible annual parallax; that explanation was not a direct observational demonstration.
Connections and context
An ancient heliocentric proposal does not imply a straight line to Copernicus. Transmission, mathematical models and available evidence all changed.
Dates and precision
c. 3rd century BCE Approximate year
An estimated date from the surviving evidence, not a claim about one exact year.
Representative map location
Alexandrian scholarly world
A representative scholarly location; the model's exact place and year of formulation are uncertain.
Representative coordinates · 31.2°, 29.92°
A marker identifies one representative place, such as a manuscript collection, laboratory or observing site. It does not mean the work happened only there, or assign a shared discovery to one country.
Bibliography
- UCAR, High Altitude Observatory | Aristarchus of Samos
- NASA Goddard | Ask an Astrophysicist: Who discovered that the Earth orbits the Sun?
References are listed as plain bibliography titles. They support particular facts or context; a reference does not certify every interpretation in a story.