1473 – 1543
During Copernicus’s time, most believed that the earth was at the center of the universe and that the other celestial bodies revolved around it. Copernicus observed that the planets would travel back wards over several nights of observation. Greek astronomer Ptolemy attributed this to the idea that the planets made circles within their orbit but Copernicus was not convinced.
- Copernicus proposed that the planets rotated around the sun rather than the earth
- Showed that the motion of the earth caused the retrograde movement of the other planets
- Suggested that Earth’s rotation accounted for the rising and the setting of the sun
- Proposed that the earth’s revolutions around the sun were responsible for the cycle of the seasons