The Ancient Greeks

Championed by Aristotle, the the theory of a Round Earth began in classical antiquity, contradicting the prevailing belief of a Flat Earth. Aristotle founded his theory on three proofs, which are still in use today. As Greek and Roman influence and culture spread throughout the ages the concept of a Round Earth overthrew the ancient knowledge, establishing itself as the cornerstone of Western civilization.

Aristotle's Round Earth Proofs
Aristotle is credited as being the first to propose that the earth was round based on physical evidence. Around this time the Greek philosophers had begun to believe that the world could be explained by natural processes. The Ancient Greek philosophers rejected the prevailing divine descriptions and processes of the world as absurdities, instead searching for alternative explanations. In this effort the leading philosophers of the day sparked a movement which continues this very day. The Round Earth Theory is hearalded as the bastion of Western Science, which is prided to have been discovered entirely through human reason and intellect.

Aristotle gives three observations for the new world model:

Sinking Ship Effect
Aristotle's first proof is the observation that ships at sea appear to sink as they recede past the horizon, providing demonstration that the Earth is a globe. If the Earth is round, then it stands that bodies will sink as they recede from the observer. In the mid-1800's Samuel Rowbotham demonstrated that this proof of sinking ships was inconsistent, and that one can often see further than should be possible. Beginning in 2012 long duration time-lapse photography of the sinking effect became available, showing that it is an inconsistent optical effect.

See the Sinking Ship Effect

Celestial Sphere
Aristotle said that the southern constellations appear to rise as you traveled southwards. This was another proof that the earth was globular, since if the earth were flat we should see all of the stars at once. This proof relies on certain axioms in nature which the Ancient Greeks did not study or demonstrate. It was assumed that light travels in straight lines at all scales, or that the perspective lines recede infinitely into the distance without merging. Alternatively, if light naturally bends upwards over very long distances it could create the celestial sphere effect.

See Electromagnetic Acceleration

Lunar Eclipse
Aristotle points to the Lunar Eclipse as proof that the Earth is round. Aristotle said that only a round Earth could create a round shadow. Looking further, this is untrue. A slightly concave or flat-sided shadow projected onto the small convex surface of a sphere could also create a convexly curved shadow.

See the section Lunar Eclipse due to EA - Curved Shadow

Eratosthenes' Shadow Experiment
Eratosthenes is famed for his shadow experiment where he determined the circumference of the Round Earth and the distance to the sun. However, this experiment assumes that the earth is a globe and that the sun is far away. The experiment can also be interpreted under a Flat Earth model as well. See:
 * Eratosthenes on Diameter
 * Distance to the Sun

Continuous Universe
The Ancient Greeks believed in a Continuous Universe. This Ancient Greek concept of a perfect universe assumes the following:
 * That perfect circles can exist
 * That one could zoom into a circle forever and see a curve
 * That any length of space can be divided into infinitely smaller parts
 * That the space can be infinitely long
 * Time can likewise be infinitely divided, or infinitely long
 * Light rays travel in perfectly straight lines into infinity
 * The Perspective Lines receded infinitely and continuously into the distance